SEMI S2-0818E

ENVIRONMENTAL, HEALTH, AND SAFETY GUIDELINE FOR SEMICONDUCTOR MANUFACTURING EQUIPMENT

This Safety Guideline was technically approved by the Environmental Health & Safety Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 17, 2018. Available at www.semiviews.org and www.semi.org in August 2018; originally published in 1991; previously published March 2017.E This Standard was editorially modified in December 2018 to correct errors. A change was made to §  4 to remove an obsolete reference, and to § 5 to restore the missing definition of gas panel enclosure.

NOTICE: Paragraphs entitled ‘NOTE:’ are not an official part of this Standard or Safety Guideline and are not intended to modify or supersede the official Standard or Safety Guideline. These have been supplied by the global technical committee to enhance the usage of the Standard or Safety Guideline.

Table of Contents1 Purpose.........................................................................................................................................................................3

2 Scope............................................................................................................................................................................3

3 Limitations...................................................................................................................................................................3

4 Referenced Standards and Documents.........................................................................................................................3

5 Terminology.................................................................................................................................................................5

6 Safety Philosophy......................................................................................................................................................11

7 General Provisions.....................................................................................................................................................13

8 Evaluation Process.....................................................................................................................................................13

9 Documents Provided to User.....................................................................................................................................16

10 Hazard Alert Labels.................................................................................................................................................18

11 Safety Interlock Systems..........................................................................................................................................18

12 Emergency Shutdown..............................................................................................................................................20

13 Electrical Design......................................................................................................................................................21

14 Fire Protection..........................................................................................................................................................24

15 Process Liquid Heating Systems..............................................................................................................................30

16 Ergonomics and Human Factors..............................................................................................................................30

17 Hazardous Energy Isolation.....................................................................................................................................30

18 Mechanical Design...................................................................................................................................................31

19 Seismic Protection...................................................................................................................................................38

20 Automated Material Handlers..................................................................................................................................40

21 Environmental Considerations.................................................................................................................................40

22 Exhaust Ventilation..................................................................................................................................................42

23 Chemicals.................................................................................................................................................................44

24 Ionizing Radiation....................................................................................................................................................46

25 Non-Ionizing Radiation and Fields..........................................................................................................................47

1 SEMI S2-0818E © SEMI 1991, 2018

26 Lasers.......................................................................................................................................................................49

27 Sound Pressure Level...............................................................................................................................................50

28 Related Documents..................................................................................................................................................51

Appendix 1 Design Guidelines for Equipment Using Liquid Chemicals — Design and Test Method Supplement Intended for Internal and Third Party Evaluation Use..................................................................................................52

Appendix 2 Ionizing Radiation Test Validation — Design and Test Method Supplement Intended for Internal and Third Party Evaluation Use...........................................................................................................................................54

Appendix 3 Exposure Criteria and Test Methods for Non-Ionizing Radiation (Other Than Laser) and Electromagnetic Fields..................................................................................................................................................55

Appendix 4 Fire Protection: Flowchart for Selecting Materials of Construction.........................................................61

Appendix 5 Laser Data Sheet — SEMI S2...................................................................................................................62

Related Information 1 Equipment/Product Safety Program.........................................................................................65

Related Information 2 Additional Standards That May Be Helpful.............................................................................69

Related Information 3 Emo Reach Considerations.......................................................................................................72

Related Information 4 Seismic Protection....................................................................................................................73

Related Information 5 Continuous Hazardous Gas Detection......................................................................................83

Related Information 6 Documentation of Ionizing Radiation (§ 24 and Appendix 2) Including Rationale for Changes.......................................................................................................................................................................................85

Related Information 7 Documentation of Non-Ionizing Radiation (§ 25 and Appendix 3) Including Rationale for Changes.........................................................................................................................................................................87

Related Information 8 Laser Equipment Safety Features.............................................................................................90

Related Information 9 Laser Certification Requirements by Region of Use................................................................92

Related Information 10 Other Requirements by Region of Use...................................................................................94

Related Information 11 Light Tower Color and Audible Alert Codes.........................................................................96

Related Information 12 Surface Temperature Documentation.....................................................................................97

Related Information 13 Recommendations For Designing and Selecting Fail-to-Safe Equipment Control Systems (FECS) with Solid State Interlocks And Emo............................................................................................................100

Related Information 14 Additional Considerations for Fire Suppression Systems....................................................113

Related Information 15 Remote Operation.................................................................................................................116

Related Information 16 Design Principles and Test Methods for Evaluating Equipment Exhaust Ventilation — Design and Test Method Supplement Intended for Internal and Third Party Evaluation Use...................................118

Related Information 17 Additional Guidance for Safety Functions...........................................................................125

Related Information 18 Design Criteria For Platforms, Steps, and Ladders..............................................................134

SEMI S2-0818E © SEMI 1991, 2018 2

1 Purpose1.1 This Safety Guideline is intended as a set of performance-based environmental, health, and safety (EHS) considerations for semiconductor manufacturing equipment.

2 Scope2.1 Applicability — This Safety Guideline applies to equipment used to manufacture, measure, assemble, and test semiconductor products.

1: The list of section numbers and their titles that were shown in ¶ 2.2 in previous revisions of SEMI S2 have been relocated to the front of the main part of the Document into the Table of Contents.

2.2 Precedence of Sectional Requirements — In the case of conflict between provisions in different sections of this Safety Guideline, the section or subsection specifically addressing the technical issue takes precedence over the more general section or subsection.

NOTICE: SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the Documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.

3 Limitations3.1 This Safety Guideline is intended for use by supplier and user as a reference for EHS considerations. It is not intended to be used to verify compliance with local regulatory requirements.

3.2 It is not the philosophy of this Safety Guideline to provide all of the detailed EHS design criteria that may be applied to semiconductor manufacturing equipment. This Safety Guideline provides industry-specific criteria, and refers to some of the many international codes, regulations, standards, and specifications that should be considered when designing semiconductor manufacturing equipment.

3.3 This Safety Guideline is not intended to be applied retroactively.

3.3.1 Equipment models with redesigns that significantly affect the EHS aspects of the equipment should conform to the latest version of SEMI S2.

3.3.2 Models and subsystems that have been assessed to a previous version of SEMI S2 should continue to meet the previous version, or meet a more recently published version, and are not intended to be subject to the provisions of this version.

3.4 In many cases, references to standards have been incorporated into this Safety Guideline. These references do not imply applicability of the entire standards, but only of the sections referenced.

4 Referenced Standards and Documents4.1 SEMI Standards and Safety Guidelines

SEMI E6 — Guide for Semiconductor Equipment Installation Documentation

SEMI F5 — Guide for Gaseous Effluent Handling

SEMI F14 — Guide for the Design of Gas Source Equipment Enclosures

SEMI S1 — Safety Guideline for Equipment Safety Labels

SEMI S3 — Safety Guideline for Process Liquid Heating Systems

SEMI S6 — Environmental, Health, and Safety Guideline for Exhaust Ventilation of Semiconductor Manufacturing Equipment

SEMI S7 — Safety Guideline for Evaluating Personnel and Evaluating Company Qualifications

SEMI S8 — Safety Guideline for Ergonomics Engineering of Semiconductor Manufacturing Equipment

SEMI S10 — Safety Guideline for Risk Assessment and Risk Evaluation Process

3 SEMI S2-0818E © SEMI 1991, 2018

SEMI S12 — Environmental, Health and Safety Guideline for Manufacturing Equipment Decontamination

SEMI S13 — Environmental, Health and Safety Guideline for Documents Provided to the Equipment User for Use with Manufacturing Equipment

SEMI S14 — Safety Guidelines for Fire Risk Assessment and Mitigation for Semiconductor Manufacturing Equipment

SEMI S22 — Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment

[4.2 ] ANSI ® Standards1

ANSI/RIA® 2 R15.06 — Industrial Robots and Robot Systems – Safety Requirements

ANSI/ISA® 3 84.00.01 — Functional Safety: Safety Instrumented Systems for the Process Industry Sector

4.2 [4.3 ] CEN® /CENELEC® 4 Standards5

CEN EN 775 — Manipulating Industrial Robots – Safety

CEN EN 1050 — Safety of Machinery – Principles of Risk Assessment

CEN EN 1127-1 — Explosive Atmospheres – Explosion Prevention and Protection – Part 1: Basic Concepts and Methodology

4.3 [4.4 ] DIN® Standards6

DIN V VDE® 7 0801 — Principles for Computers in Safety-Related Systems

4.4 [4.5 ] IEC Standards8

IEC 60825-1 — Safety of Laser Products – Part 1: Equipment Classification, Requirements

IEC 61010-1 — Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use – Part 1: General Requirements

IEC 61508 — Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems

4.5 [4.6 ] IEEE® Standards9

IEEE C95.1 — Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz

4.6 [4.7 ] ISO® Standards10

ISO 2415 — Forged Shackles for General Lifting Purposes Dee Shackles and Bow Shackles

ISO 10218-1 — Robots and Robotic Devices – Safety Requirements for Industrial Robots – Part 1: Robots

ISO 13849-1 — Safety of Machinery – Safety-Related Parts of Control Systems – Part 1: General Principles for Design

1 American National Standards Institute, 25 West 43rd Street, New York, NY 10036, USA; Telephone: +1.212.642.4900, Fax: +1.212.398.0023, http://www.ansi.org ANSI trademark is owned by American National Standards Institute2 RIA trademark is owned by Robotic Industries Association.3 ISA trademark is owned by International Society of Automation.4 CENELEC trademark is owned by European Committee for Standardization5 European Committee for Standardization, Avenue Marnix 17, B-1000 Brussels; Telephone: +32.2.550.08.11, Fax: +32.2.550.08.19, http://www.cen.eu CEN trademark is owned by European Committee for Standardization.6 Deutsches Institut für Normung e.V., Available from Beuth Verlag GmbH, Burggrafenstrasse 4-10, D-10787 Berlin, Germany; http://www.din.de DIN trademark is owned by Deutsches Institut für Normung e.V.7 VDE trademark is owned by Verband Deutscher Elektrotechniker e.V.8 International Electrotechnical Commission, 3 rue de Varembé, Case Postale 131, CH-1211 Geneva 20, Switzerland; Telephone: +41.22.919.02.11, Fax: +41.22.919.03.00, http://www.iec.ch IEC trademark is owned by International Electrotechnical Commission9 Institute of Electrical and Electronics Engineers, 3 Park Avenue, 17th Floor, New York, NY 10016-5997, USA; Telephone: +1.212.419.7900, Fax: +1.212.752.4929, http://www.ieee.org IEEE trademark is owned by The Institute of Electrical and Electronics Engineers, Inc.10 International Organization for Standardization, ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland; Telephone: +41.22.749.01.11, http://www.iso.org ISO trademark is owned by International Organization for Standardization

SEMI S2-0818E © SEMI 1991, 2018 4

4.7 [4.8 ] NFPA® Standards11

NFPA 12 — Standard on Carbon Dioxide Extinguishing Systems

NFPA 13 — Standard for the Installation of Sprinkler Systems

NFPA 72® 12 — National Fire Alarm and Signaling Code

NFPA 497 — Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas

NFPA 704 — Standard System for the Identification of the Hazards of Materials for Emergency Response

NFPA 2001 — Standard on Clean Agent Fire Extinguishing Systems

4.8 [4.9 ] Underwriters Laboratories® Standards13

UL® 14 508A — Standard for Industrial Control Panel

4.9 [4.10 ] US Code of Federal Regulations15

21 CFR Parts 1000-1050 — Food and Drug Administration/Center for Devices and Radiological Health (FDA/CDRH), Performance Standards for Electronic Products, Title 21 Code of Federal Regulations, Parts 1000-1050

4.10 [4.11 ] Other Standards and Documents

ACGIH® , Industrial Ventilation Manual16

ASHRAE® Standard 110 — Method of Testing Performance of Laboratory Fume Hoods17

Burton, D.J., Semiconductor Exhaust Ventilation Guidebook18

Uniform Building Code™ (UBC)19

Uniform Fire Code™20

NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

5 Terminology5.1 Abbreviations and Acronyms

[5.1.1 ] ACGIH® — American Conference of Governmental Industrial Hygienists (ACGIH is a registered trademark of the American Conference of Governmental Industrial Hygienists.)

5.1.1 [5.1.2 ] ASHRAE — American Society of Heating, Refrigeration, and Air Conditioning Engineers

5.1.2 [5.1.3 ] IOHA — International Occupational Hygiene Association

5.1.3 [5.1.4 ] LFL — lower flammability limit

5.1.4 [5.1.5 ] MPE — maximum permissible exposure

11 National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02269, USA; Telephone: +1.617.770.3000, Fax: +1.617.770.0700, http://www.nfpa.org NFPA trademark is owned by National Fire Protection Association.12 NFPA 72 trademark is owned by National Fire Protection Association.13 Underwriters LaboratoryLaboratories, 2600 N.W. Lake Road, Camas, WA 98607-8542, USA; Telephone: +1.877.854.3577, Fax: +1.360.817.6278, http://www.ul.com Underwriters Laboratories trademark is owned by Underwriters Laboratories Inc.14 UL trademark is owned by UL LLC.15 United States Food and Drug Administration/ Center for Devices and Radiological Health (FDA/CDRH). Available from FDA/CDRH; http:// www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm 16 ACGIH, 1330 Kemper Meadow Road, Cincinnati, OH 45240, USA. http:// www.acgih.org ACGIH trademark is owned by American Conference of Governmental Industrial Hygienists, Inc.17 ASHRAE, 1791 Tullie Circle, NE, Atlanta, GE 30329, USA. http:// www.ashrae.org ASHRAE trademark is owned by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.18 IVE, Inc., 2974 South Oakwood, Bountiful, UT 84010, USA. http:// www.eburton.com 19 International Conference of Building Officials, 5360 Workman Mill Road, Whittier, CA 90601-2298, USA. http:// www.icbo.org 20 International Fire Code Institute, 5360 Workman Mill Road, Whittier, CA 90601-2298, USA. http:// www.ifci.org

5 SEMI S2-0818E © SEMI 1991, 2018

5.1.5 [5.1.6 ] NIOSH® 21 — National Institute of Occupational Safety and Health – part of United States Centers for Disease Control and Prevention

5.1.6 [5.1.7 ] NOHD — nominal ocular hazard distance

5.1.7 [5.1.8 ] OSHA® 22 — Occupational Safety and Health Administration –an agency of United States Department of Labor

5.1.8 [5.1.9 ] SOC — substance of concern

5.2 Definitions

2: Composite reports using portions of reports based upon earlier versions of SEMI S2 and SEMI S10 may require understanding of the SEMI S2-0703 or SEMI S10-1296 definitions for the terms hazard, likelihood, mishap, severity, and risk.

5.2.1 abort switch — a switch that, when activated, interrupts the activation sequence of a fire detection or fire suppression system.

5.2.2 accredited testing laboratory — an independent organization dedicated to the testing of components, devices, or systems that is recognized by a governmental or regulatory body as competent to perform evaluations based on established safety standards.

5.2.3 anchor point — a location or device which receives the load in a fall arrest or restraint system and to which the other components of that system are connected.

5.2.4 baseline — for the purposes of this Document, ‘baseline’ refers to operating conditions, including process chemistry, for which the equipment was designed and manufactured.

5.2.5 breathing zone — imaginary globe, of 600 mm (2 ft.) radius, surrounding the head.

5.2.6 capture velocity — the air velocity that at any point in front of the exhausted hood or at the exhausted hood opening is necessary to overcome opposing air currents and to capture the contaminated air at that point by causing it to flow into the exhausted hood.

5.2.7 carcinogen — confirmed or suspected human cancer-causing agent as defined by the International Agency for Research on Cancer (IARC) or other recognized entities.

5.2.8 certified anchor point — an anchor point that a qualified person certifies to be capable of supporting the forces foreseen to be applied to it by fall arrest or fall restraint system.

5.2.9 chemical distribution system — the collection of subsystems and components used in a semiconductor manufacturing facility to control and deliver process chemicals from source to point of use for wafer manufacturing processes.

5.2.10 cleanroom — a room in which the concentration of airborne particles is controlled to specific limits.

5.2.11 combustible material — for the purpose of this Safety Guideline, a combustible material is any material that does propagate flame (beyond the ignition zone with or without the continued application of the ignition source) and does not meet the definition in this section for noncombustible material. See also the definition for noncombustible material.

5.2.12 elevated location — a walking or working surface occupancy of which results in the feet being at 500 mm (19.7 in.) or more above an adjacent surface.

5.2.13 equipment — a specific piece of machinery, apparatus, process module, or device used to execute an operation. The term ‘equipment’ does not apply to any product (e.g., substrates, semiconductors) that may be damaged as a result of equipment failure.

5.2.14 face velocity — velocity at the cross-sectional entrance to the exhausted hood.

5.2.15 facilitization — the provision of facilities or services.

5.2.16 fail-safe — designed so that a failure does not result in an increased risk.

21 NIOSH trademark is owned by U.S. Department of Health and Human Services.22 OSHA trademark is owned by Occupational Safety and Health Administration, U.S. Dept. of Labor.

SEMI S2-0818E © SEMI 1991, 2018 6

3: For example, a fail-safe temperature limiting device would indicate an out-of-control temperature if it were to fail. This might interrupt a process, but would be preferable to the device indicating that the temperature is within the control limits, regardless of the actual temperature, in case of a failure.

5.2.17 fail-to-safe equipment control system (FECS) — a safety-related programmable system of control circuits designed and implemented for safety functions in accordance with recognized standards such as ISO 13849-1 (EN 954-1) or IEC 61508, ANSI/ISA 84.00.01. These systems (e.g., safety programmable logic controller (PLC), safety-related input and output (I/O) modules) diagnose internal and external faults and react upon detected faults in a controlled manner in order to bring the equipment to a safe state.

4: A FECS is a subsystem to a programmable electronic system (PES) as defined in IEC 61508-4 Definitions.

5: Related Information RELATED INFORMATION 13 provides additional information on applications of FECS design.

5.2.18 failure — the termination of the ability of an item to perform a required function. Failure is an event, as distinguished from ‘fault,’ which is a state.

5.2.19 fall arrest — stopping a person in free fall.

5.2.20 fall protection — engineered or administrative controls that reduce the risk of a fall.

5.2.21 fall restraint — preventing a person’s center of gravity reaching a fall hazard by use of a harness, lanyard, and connectors.

5.2.22 fault — the state of an item characterized by inability to perform a required function, excluding the inability during preventive maintenance or other planned actions, or due to lack of external resources.

5.2.23 fault-tolerant — designed so that a reasonably foreseeable single point failure does not result in an unsafe condition.

5.2.24 flammable gas — any gas that forms an ignitable mixture in air at 20C (68F) and 101.3 kPa (14.7 psia).

5.2.25 flammable liquid — a liquid having a flash point below 37.8C (100F).

5.2.26 flash point — the minimum temperature at which a liquid gives off sufficient vapor to form an ignitable mixture with air near the surface of the liquid, or within the test vessel used.

5.2.27 gas cylinder cabinet — cabinet used for housing gas cylinders, and connected to gas distribution piping or to equipment using the gas. Synonym: gas cabinet.

5.2.28 gas panel — an arrangement of fluid handling components (e.g., valves, filters, mass flow controllers) that regulates the flow of fluids into the process. Synonyms: gas jungle, jungle, gas control valves, valve manifold.

5.2.29 gas panel enclosure — an enclosure designed to contain leaks from gas panel(s) within itself. Synonyms: jungle enclosure, gas box, valve manifold box.

5.2.30 guardrail system — a physical barrier positioned at a prescribed height to prevent a fall from an elevated location. It consists of posts (vertical supports), a toprail, a midrail, and, in some cases, a toeboard. Synonyms: jungle enclosure, gas box, valve manifold box.

5.2.31 handrail — a horizontal or inclined member designed to be grasped by the hand for support.

6: Unlike a guardrail system, a handrail is not intended to keep personnel from falling from an elevated location.

5.2.32 harm — physical injury or damage to health of people, or damage to equipment, buildings, or environments.

5.2.33 hazard — condition that has the potential to cause harm.

5.2.34 hazardous electrical power — power levels equal to or greater than 240 VA.

5.2.35 hazardous production material (HPM) — a solid, liquid, or gas that has a degree-of-hazard rating in health, flammability, or reactivity of class 3 or 4 as ranked by NFPA 704 and which is used directly in research, laboratory, or production processes that have as their end product materials that are not hazardous.

5.2.36 hazardous voltage — unless otherwise defined by an appropriate international standard applicable to the equipment, voltages greater than 30 volts rms, 42.4 volts peak, 60 volts dc are defined in this Document as hazardous voltage.

7 SEMI S2-0818E © SEMI 1991, 2018

7: The specified levels are based on normal conditions in a dry location.

5.2.37 hinged load — a load supported by a hinge such that the hinge axis is not vertical.

5.2.38 hood — in the context of § 22 of this Safety Guideline, ‘hood’ means a shaped inlet designed to capture contaminated air and conduct it into an exhaust duct system.

5.2.39 incompatible — as applied to chemicals: in the context of § 23 of this Safety Guideline, describes chemicals that, when combined unintentionally, may react violently or in an uncontrolled manner, releasing energy that may create a hazardous condition.

5.2.40 intended reaction product — chemicals that are produced intentionally as a functional part of the semiconductor manufacturing process.

5.2.41 interlock — a mechanical, electrical or other type of device or system, the purpose of which is to prevent or interrupt the operation of specified machine elements under specified conditions.

5.2.42 ionizing radiation — alpha particles, beta particles, gamma rays, X-rays, neutrons, high-speed electrons, high-speed protons, and other particles capable of producing ions in human tissue.

5.2.43 ladder — a fixed or portable means of access with a pitch more than 75° but not more than 90°, whose horizontal elements are steps or rungs.

5.2.44 landing — a horizontal elevated location, not intend by the supplier as a location of work, at the end of a series of steps.

5.2.45 laser — any device that can be made to produce or amplify electromagnetic radiation in the wavelength range from 180 nm to 1 mm primarily by the process of controlled stimulated emission.

5.2.46 laser product — any product or assembly of components that constitutes, incorporates, or is intended to incorporate a laser or laser system (including laser diode), and that is not sold to another manufacturer for use as a component (or replacement for such component) of an electronic product.

5.2.47 laser source — any device intended for use in conjunction with a laser to supply energy for the excitation of electrons, ions, or molecules. General energy sources, such as electrical supply mains, should not be considered to be laser energy sources.

5.2.48 laser system — a laser in combination with an appropriate laser energy source, with or without additional incorporated components.

5.2.49 lifting accessory — a component (e.g., eyehook, shackle, hoist ring, wire rope, chain, or eyebolt) which is part of a lifting fixture or is attached directly between the lifting device and the load in order to lift it.

5.2.50 lifting device — a mechanical or electro-mechanical structure that is provided for the purpose of raising and lowering a load during maintenance or service tasks, and may be capable of moving the load in one or more horizontal directions.

5.2.51 lifting equipment — lifting devices, lifting fixtures and lifting accessories.

5.2.52 lifting fixture — a mechanical device or an assembly of lifting accessories (e.g., hoisting yoke, wire rope sling, webbing sling, or chain assembly) placed between the lifting device (but not permanently attached to it) and the load, in order to attach them to each other.

5.2.53 likelihood — the expected frequency with which harm will occur. Usually expressed as a rate (e.g., events per year, per product, or per substrate processed).

5.2.54 local exhaust ventilation — local exhaust ventilation systems operate on the principle of capturing a contaminant at or near its source and moving the contaminant to the external environment, usually through an air cleaning or a destructive device. It is not to be confused with laminar flow ventilation. Synonyms: LEV, local exhaust, main exhaust, extraction system, module exhaust, individual exhaust.

5.2.55 lower flammable limit (LFL) — the minimum concentration of a flammable substance in air through which a flame will propagate. Synonyms: lower explosive limit (LEL)

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5.2.56 maintenance — planned or unplanned activities intended to keep equipment in good working order. See also the definition for service.

5.2.57 mass balance — a qualitative, and where possible, quantitative, specification of mass flow of input and output streams (including chemicals, gases, water, de-ionized water, compressed air, nitrogen, and by-products), in sufficient detail to determine the effluent characteristics and potential treatment options.

5.2.58 material safety data sheet (MSDS) — written or printed material concerning chemical elements and compounds, including hazardous materials, prepared in accordance with applicable standards.

5.2.59 maximum permissible exposure (MPE) — level of laser radiation to which, under normal circumstances, persons may be exposed without suffering adverse effects.

5.2.60 midrail — the linear element of a guardrail system that is approximately midway between the toprail and the walking or working surface.

5.2.61 nominal ocular hazard distance (NOHD) — distance at which the beam irradiance or radiant exposure equals the appropriate corneal maximum permissible exposure (MPE).

8: Examples of such standards are USA government regulation 29 CFR 1910.1200, and Canadian WHMIS (Workplace Hazardous Material Information System).

5.2.62 noncombustible material — a material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat. Typical noncombustible materials are metals, ceramics, and silica materials (e.g., glass and quartz). See also the definition for combustible material.

5.2.63 non-ionizing radiation — forms of electro-magnetic energy that do not possess sufficient energy to ionize human tissue by means of the interaction of a single photon of any given frequency with human tissue. Non-ionizing radiation is customarily identified by frequencies from zero hertz to 3 × 1015 hertz (wavelengths ranging from infinite to 100 nm). This includes: static fields (frequencies of 0 hertz and infinite wavelengths); extremely low frequency fields (ELF), which includes power frequencies; sub radio-frequencies; radiofrequency/microwave energy; and infrared, visible, and ultraviolet energies.

5.2.64 non-recycling, deadman-type abort switch — a type of abort switch that must be constantly held closed for the abort of the fire detection or suppression system. In addition, it does not restart or interrupt any time delay sequence for the detection or suppression system when it is activated.

5.2.65 occupational exposure limits (OELs) — for the purpose of this Document, OELs are generally established on the basis of an eight hour workday. Various terms are used to refer to OELs, such as permissible exposure levels, Threshold Limit Values, maximum acceptable concentrations, maximum exposure limits, and occupational exposure standards. However, the criteria used in determining OELs can differ among the various countries that have established values. Refer to the national bodies responsible for the establishment of OELs. (Threshold Limit Value is a registered trademark of the American Conference of Governmental Industrial Hygienists.)

5.2.66 operator — a person who interacts with the equipment only to the degree necessary for the equipment to perform its intended function.

5.2.67 parts-cleaning hood — exhausted hood used for the purpose of cleaning parts or equipment. Synonym: equipment cleaning hood.

5.2.68 placed on the market — made physically available, regardless of the legal aspects of the act of transfer (loan, gift, sale, hire).

5.2.69 platform — a horizontal elevated location intended by the supplier to support the weight of personnel, their tools, and equipment while working.

5.2.70 platform stand — a fixed-height, self-supporting, movable unit consisting of one or more platforms on a rigid base (with or without wheels or casters) and a means of ascending or descending between levels.

5.2.71 positive-opening — as applied to electromechanical control devices. The achievement of contact separation as a direct result of a specified movement of the switch actuator through non-resilient members (i.e., contact separation is not dependent upon springs).

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5.2.72 potentially hazardous non-ionizing radiation emissions — for the purposes of this Safety Guideline, non-ionizing radiation emissions outside the limits shown in Appendix APPENDIX 4 are considered potentially hazardous.

5.2.73 pyrophoric material — a chemical that will spontaneously ignite in air at or below a temperature of 54.4°C (130°F).

5.2.74 qualified person (fall arrest and restraint systems) — individual having extensive knowledge, training, and experience designing, analyzing, evaluating and specifying fall arrest and restraint systems.

5.2.75 radio frequency (rf) — electromagnetic energy with frequencies ranging from 3 kHz to 300 GHz. Microwaves are a portion of rf extending from 300 MHz to 300 GHz.

5.2.76 readily accessible — capable of being reached quickly for operation or inspection, without requiring climbing over or removing obstacles, or using portable ladders, chairs, etc.

5.2.77 recognized — as applied to standards; agreed to, accepted, and practiced by a substantial international consensus.

5.2.78 rem — unit of dose equivalent. Most instruments used to measure ionizing radiation read in dose equivalent (rems or sieverts). 1 rem = 0.01 sievert.

5.2.79 reproductive toxicants — chemicals that are confirmed or suspected to cause statistically significant increased risk for teratogenicity, developmental effects, or adverse effects on embryo viability or on male or female reproductive function at doses that are not considered otherwise maternally or paternally toxic.

5.2.80 residual — as applied to risks or hazards: that which remains after engineering, administrative, and work practice controls have been implemented.

5.2.81 risk — the expected magnitude of losses from a hazard, expressed in terms of severity and likelihood.

5.2.82 rung — a horizontal crosspiece of a ladder, intended by the supplier to be used both to support feet and to be gripped by hands.

5.2.83 safe shutdown condition — a condition in which all hazardous energy sources are removed or suitably contained and hazardous production materials are removed or contained, unless this results in additional hazardous conditions.

5.2.84 safety critical part — discrete device or component, such as used in a power or safety circuit, whose proper operation is necessary to the safe performance of the system or circuit.

5.2.85 service — unplanned activities intended to return equipment that has failed to good working order. See also the definition for maintenance.

5.2.86 severity — the extent of potential credible harm.

5.2.87 short circuit current rating — the maximum available current to which an equipment supply circuit is intended, by the equipment manufacturer, to be connected.

9: Short circuit current rating for an electrical system is typically based on the analysis of short circuit current ratings of the components within the system. See UL 508A and Related Information 2 of SEMI S22 for methods of determining short circuit rating.

5.2.88 sievert (Sv) — unit of dose equivalent. Most instruments used to measure ionizing radiation read in dose equivalent (rems or sieverts). 1 Sv = 100 rems.

5.2.89 stair ladder — fixed or portable means of access with a pitch more than 45° but not more than 75°, whose horizontal elements are steps or rungs.

5.2.90 stairs — fixed or portable means of access with a pitch not more than 45°, whose horizontal elements are steps.

5.2.91 standard temperature and pressure — for ventilation measurements, either dry air at 21°C (70°F) and 760 mm (29.92 inches) Hg, or air at 50% relative humidity, 20°C (68°F), and 760 mm (29.92 inches) Hg.

SEMI S2-0818E © SEMI 1991, 2018 10

5.2.92 step — a horizontal surface, other than a rung, landing, or platform, intended by the supplier to support ascent or descent of people.

5.2.93 supervisory alarm — as applied to fire detection or suppression systems; an alarm indicating a supervisory condition.

5.2.94 supervisory condition — as applied to fire detection or suppression systems; condition in which action or maintenance is needed to restore or continue proper function.

5.2.95 supplemental exhaust — local exhaust ventilation that is used intermittently for a specific task of finite duration.

5.2.96 supplier — party that provides equipment to, and directly communicates with, the user. A supplier may be a manufacturer, an equipment distributor, or an equipment representative. See also the definition for user.

5.2.97 task — a group of related job elements directed toward a specific objective.

5.2.98 task analysis — determining the specific actions required of the user when operating, maintaining, or servicing equipment. Within each task, steps are described in terms of the perception, decision-making, memory, posture, and biomechanical requirements as well as the expected errors.

5.2.99 toeboard — a vertical barrier erected along an edge of a walking or working surface to reduce falls of materials.

5.2.100 testing — the term ‘testing’ is used to describe measurements or observations used to validate and document conformance to designated criteria.

5.2.101 toprail — the linear element of a guardrail system that is farthest from the walking or working surface.

5.2.102 trouble alarm — as applied to fire detection or suppression systems; an alarm indicating a trouble condition.

5.2.103 trouble condition — as applied to fire detection or suppression systems; a condition in which there is a fault in a system, subsystem, or component that may interfere with proper function.

5.2.104 user — party that acquires equipment for the purpose of using it to manufacture semiconductors. See also the definition for supplier.

5.2.105 validated method — as applied for the purposes of industrial hygiene chemical exposure testing, is a reviewed documented protocol for the collection and analysis of a sample (e.g., NIOSH sampling method 1300). A validated method includes instructions on collection (media, efficiency, volume, flow rate, etc.), sample handling, analytical method, lower sensitivity and method error statistics. Validated methods are published by agencies or industrial hygiene organizations such as NIOSH, OSHA, IOHA or ACGIH.

5.2.106 velocity pressure (VP) — the pressure required to accelerate air from zero velocity to some velocity V. Velocity pressure is proportional to the kinetic energy of the air stream. Associated equation:

VP = (V/4.043)2 (1)

where:

V = air velocity in m/s

VP = velocity pressure in mm water gauge (w.g.)

U.S. units: VP = (V/4005)2 (2)

where:

V = velocity in feet per second

VP = velocity pressure in inches water gauge (w.g.)

5.2.107 volumetric flow rate (Q) — in the context of § 22 of this Safety Guideline, Q = the volume of air exhausted per unit time. Associated equation:

Q = VA (3)

11 SEMI S2-0818E © SEMI 1991, 2018

where:

V = air flow velocity

A = the cross-sectional area of the duct or opening through which the air is flowing at standard conditions.

5.2.108 walking or working surface — a surface on which the supplier intends personnel to walk, stand, squat, kneel, sit, or lie for work.

5.2.109 wet station — open surface tanks, enclosed in a housing, containing chemical materials used in the manufacturing of semiconductor materials. Synonyms: wet sink, wet bench, wet deck.

5.2.110 yield strength — the stress at which a material exhibits a specified permanent deformation or set. This is the stress at which, the strain departs from the linear portion of the stress-strain curve by an offset unit strain of 0.002.23

6 Safety Philosophy6.1 A primary objective of the industry is to eliminate or control hazards during the equipment’s life cycle (i.e., the installation, operation, maintenance, service, and disposal of equipment).

6.2 The assumption is made that operators, maintenance personnel, and service personnel are trained in the tasks that they are intended to perform.

6.3 The following should be considered in the design and construction of equipment:

regulatory requirements;

industry standards;

this Safety Guideline; and

good engineering and manufacturing practices.

6.4 This Safety Guideline should be applied during the design, construction, and evaluation of semiconductor equipment, in order to reduce the expense and disruptive effects of redesign and retrofit.

6.5 No reasonably foreseeable single-point failure condition or operational error should allow exposure of personnel, facilities, or the community to hazards that could result in death, significant injury, or significant equipment damage.

10: The intent is to control single fault conditions that result in significant risks (i.e., Very High, High, or Medium risks based on the example risk assessment matrix in SEMI S10).

11: The risk category of ‘Very High’ corresponds identically to the risk category, used in previous SEMI Documents (e.g., SEMI S10-1296, SEMI S2, and SEMI S14) of ‘Critical.’ The term was changed to facilitate translation from English.

6.6 Equipment safety features should be fail-safe or of a fault-tolerant design and construction.

6.7 Components and assemblies should be used in accordance with their manufacturers’ ratings and specifications, where using them outside the ratings would create a safety hazard.

6.8 A hazard analysis should be performed to identify and evaluate hazards. The hazard analysis should be initiated early in the design phase, and updated as the design matures.

6.8.1 The hazard analysis should include consideration of:

the application or process;

the hazards associated with each task;

anticipated failure modes;

the probability of occurrence and severity of harm;

the level of expertise of exposed personnel and the frequency of exposure;

the frequency and complexity of operating, servicing and maintenance tasks; and

23 Roark’s Formulas for Stress and Strain, Seventh Edition, McGraw-Hill, 2002, p. 826.

SEMI S2-0818E © SEMI 1991, 2018 12

safety critical parts.

12: CEN EN 1050 contains examples of hazard analysis methods.

13: The term mishap was replaced with the results of harm in the SEMI S10-1103 revision.

14: Related Information RELATED INFORMATION 15 provides some discussion of safety considerations related to equipment remote control.

6.8.2 The risks associated with hazards should be characterized using SEMI S10.

6.9 The order of precedence for resolving identified hazards should be as follows:

6.9.1 Design to Eliminate Hazards — From the initial concept phase, the supplier should design to eliminate hazards.

15: It is recommended that the supplier continue to work to eliminate identified hazards.

6.9.2 Incorporate Safety Devices — If identified hazards cannot be eliminated or their associated risk adequately controlled through design selection, then the risk should be reduced through fixed, automatic, or other protective safety design features or devices.

16: It is recommended that provisions be made for periodic functional checks of safety devices, when applicable.

6.9.3 Provide Warning Devices — If design or safety devices cannot effectively eliminate identified hazards or adequately reduce associated risk, a means should be used to detect the hazardous condition and to produce a warning signal to alert personnel of the hazard.

6.9.4 Provide Hazard Alert Labels — Where it is impractical to eliminate hazards through design selection or adequately reduce the associated risk with safety or warning devices, hazard alert labels should be provided. See § 10 for label information.

6.9.5 Develop Administrative Procedures and Training — Where hazards are not eliminated through design selection or adequately controlled with safety or warning devices or hazard alert labels, procedures and training should be used. Procedures may include the use of personal protective equipment.

6.9.6 A combination of these approaches may be needed.

7 General Provisions7.1 This Safety Guideline should be incorporated by reference in equipment purchase specifications. The user and supplier should agree on deviations from this Safety Guideline. The intent is for the user to purchase equipment conforming with SEMI S2, not to design the equipment.

7.2 The equipment must comply with laws and regulations that are in effect at the location of use. All equipment requiring certification or approval by government agencies must have this certification or approval as required by regulations.

17: It is recommended that the supplier request from the user information regarding local laws and regulations.

7.3 The manufacturer should maintain an equipment/product safety program to identify and eliminate hazards or control risks in accordance with the order of precedence (see § 6.9 ).

7.3.1 The supplier should provide the user’s designated representative with bulletins that describe safety related upgrades or newly identified significant hazards associated with the equipment. This should be done on an ongoing basis as needed.

7.4 Model-specific tools and accessories necessary to operate, maintain, and service equipment safely should be provided with the equipment or specified by the supplier.

18: The official values in this Safety Guideline are expressed in The International System of Units (SI). Values that:

are expressed in Inch-Pound (also known as ‘US Customary’ or ‘English’) units,

are enclosed in parentheses,

directly follow values expressed in SI units, and

are not official, are provided for reference only, and might not be exact conversions of the SI values.

13 SEMI S2-0818E © SEMI 1991, 2018

8 Evaluation Process8.1 This section describes the evaluation of equipment to this Safety Guideline, the contents of the evaluation report, and supporting information needed to perform the evaluation.

8.2 General — The evaluating party (see § 8.4 ) should evaluate the equipment and related end user documentation according to this Safety Guideline and create a written evaluation report.

19: The intent is that the ‘should’ provisions of this Safety Guideline be used as the basis for evaluating conformance. The intent is also that the ‘may,’ ‘suggested,’ ‘preferred,’ ‘recommended,’ and ‘NOTE’ provisions of this Safety Guideline not be used for evaluating conformance.

8.2.1 Conformance to specific paragraphs of SEMI S2 may be achieved by instructions included in the supplier’s equipment installation instructions (reference SEMI E6) or other documentation.

8.3 Evaluation Report Contents: General — The evaluation report should include only the manuals (see § 9.6 ) and the design-specific sections (see §§ 10 through 27 ). The Appendices should be used in the evaluation, and referenced in the report, only as they pertain to the specific application.

8.3.1 For each numbered paragraph, the evaluation report should state one of the following, and provide supporting rationale, according to the criteria in §§ 8.3.3 through 8.3.5 :

‘N/A’

‘Conforms to the Stated Criteria’

‘Conforms to the Performance Goal’

‘Does not Conform’

EXCEPTION 1: If all of a particular section is found to be ‘N/A’, then the report may state the section is ‘N/A’ rather than state ‘N/A’ for each subordinate paragraph.

EXCEPTION 2: If the equipment aspects to which a paragraph pertains are found to be a mix of ‘Conforms to the Stated Criteria’ and ‘Conforms to the Performance Goal’, then both findings should be indicated in the report (with appropriate supporting rationale) instead of only one or the other.

20: ‘Conforms to the Stated Criteria’ and ‘Conforms to the Performance Goal’ are both findings indicating conformance. The findings are differentiated, as the appropriate supporting rationale for these findings differs.

8.3.2 Within § 8.3 , ‘equipment’ means the equipment under evaluation, or the related end user documentation provided with the equipment, as appropriate. (See SEMI S13 for the meaning of ‘end user documentation.’)

8.3.3 Not Applicable — A finding of ‘Not Applicable’ should be given if the evaluator concludes there are no equipment aspects to which the paragraph pertains.

8.3.4 Conformance Findings (‘Conforms to the Stated Criteria’ and ‘Conforms to the Performance Goal’)

8.3.4.1 A finding of ‘Conforms to the Stated Criteria’ should be given if the evaluator concludes the equipment aspects to which the paragraph pertains match the criteria stated in the text of the paragraph.

8.3.4.2 The supporting rationale for ‘Conforms to the Stated Criteria’ should include a description of the equipment aspects, and the objective information demonstrating the conformance of each to the criteria (e.g., testing, measurements, observation).

8.3.4.3 A finding of ‘Conforms to the Performance Goal’ should be given if the evaluator concludes the equipment aspects to which the paragraph pertains do not match the stated criteria, but they do meet the performance goal of the paragraph and they present a Low or Very Low Risk according to the risk assessment method of SEMI S10.

8.3.4.4 The supporting rationale for ‘Conforms to the Performance Goal’ should include:

8.3.4.4.1 a description of the equipment aspects,

8.3.4.4.2 and, to support the conclusion of meeting the performance goal;

a statement of the performance goal as it is understood by the evaluator,

the logical argument which demonstrates the performance goal has been met,

SEMI S2-0818E © SEMI 1991, 2018 14

the objective evidence used to support the argument, and

bibliographic information for references made in the argument (e.g., document title, website, reference number, author, publication date, revision).

8.3.4.4.3 and, to support the risk assessment;

the specific hazards presented by the equipment aspects,

the scenarios in which the hazards are foreseen to cause harm,

the harm foreseen in each scenario, and

the severity and likelihood analyses for each scenario.

8.3.4.5 If a standard is used in whole or in part to support the performance goal argument, the supporting rationale should include information demonstrating why the standard is applicable, the section or sections used for the evaluation, and why the sections are relevant. For the purpose of this paragraph, a standard is applicable if the equipment aspect under consideration is properly within scope, and the sections are relevant if they contain criteria having demonstrable bearing to the equipment aspects (e.g., addressing similar design considerations).

8.3.5 Does Not Conform

8.3.5.1 A finding of ‘Does Not Conform’ should be given if the evaluator concludes that one or more equipment aspects:

to which the paragraph pertains do not conform to the stated criteria and do not conform to the performance goal; or

for which there is insufficient information available to the evaluator to reach a conclusion for these or the ‘N/A’ finding.

8.3.5.2 The supporting rationale for this finding should include a description of the nonconforming equipment aspect(s), a description of the nonconforming characteristics, and a determination per SEMI S10 of the associated risk; or a description of the information needed to reach a conclusion for one of the conformance findings or the ‘N/A’ finding; as appropriate.

21: For example, ‘circuit breaker 42’ is an equipment aspect; ‘circuit breaker 42’ being a supplementary overcurrent protector rather than a circuit breaker is a characteristic.

8.3.5.3 The evaluator may include any information they wish about remaining equipment aspects which conform to the stated criteria or conform to the performance goal. None the less, it should be clear in the report that the overall finding is ‘Does Not Conform.’

8.4 Evaluation Report Contents: Other Information — The evaluation report should also include:

manufacturer’s model number;

serial number of unit(s) evaluated;

the date(s) that the equipment was evaluated;

a system/equipment description including configuration, options, and essential diagrams; and

a statement of the qualifications of the evaluating party. An in-house body, independent laboratory, or product safety consulting firm (‘third party’) meeting the provisions of SEMI S7 may be used to supply testing or evaluation of conformance to this Document.

8.5 Supporting Information Provided to Evaluator — The following documentation should be provided to, or developed by, the evaluator, as necessary to demonstrate conformance to the provisions of this Safety Guideline.

22: It is recommended that the manufacturer’s typical configuration and process be used for evaluation purposes. Alternatively, a process agreed upon between the user and the supplier may be used.

23: Special options or configurations that may pose additional hazards and are not included in the initial evaluation may need a separate review. It is recommended that upgrades, retrofits, and other changes that affect the safety design of the equipment be evaluated for conformance.

15 SEMI S2-0818E © SEMI 1991, 2018

8.5.1 General Information

Written system description, including hardware configuration and function(s), power requirements, power output, and other information necessary to understand the design and operation of the equipment.

Engineering data used to provide the rationale that the equipment and subassembly seismic anchorages are designed to satisfy the applicable design loads (see § 19 , Seismic Protection).

Descriptions of the purpose and function of safety devices, such as: emergency off devices (EMOs), interlocks, pressure relief devices, and limit controls.

A hazard analysis (see § 6.8 ).

Ergonomics evaluation (see § 16 ).

A list of safety critical parts and, for each one, evidence of certification, or documentation showing that the component is suitable for its application.

A residual fire risk assessment as described in § 14.2 .

Tests results, certifications, and design specifications that are necessary to evaluate the equipment with respect to fire safety. Descriptions of the fire detection and suppression equipment and controls should also be provided.

8.5.2 Industrial Hygiene Information

8.5.2.1 An industrial hygiene report, which should include, as applicable:

ventilation assessment (see § 22 );

chemical inventory and hazard analysis (see § 23 );

ionizing radiation assessment (see § 24 );

non-ionizing radiation assessment (see § 25 );

laser assessment (see § 26 ); and

audio sound pressure level assessment (see § 27 ).

8.5.3 Environmental Information (see § 21 ) — Documentation substantiating the following:

consideration or inclusion of features that conserve resources (e.g., energy, water, deionized water, compressed gases, chemicals, and packaging);

consideration of features that would promote equipment and component reuse or refurbishing, or material recycling upon decommissioning;

consideration or inclusion of features for resource recycling or reuse;

chemical selection methods and criteria (see § 21.2.3 );

consideration of integrating effluent and emission controls into the equipment; and

efforts to reduce wastes, effluents, emissions, and by-products.

24: For purposes of § 8.5.3 , documentation may include design notes, metrics (whether normalized or not), meeting minutes, pareto evaluations, or other analyses.

9 Documents Provided to User9.1 This section describes the documents that the supplier provides to the user.

9.2 Evaluation Report — Upon request by the user, the supplier should provide the user with a summary of the SEMI S2 evaluation report (see § 8 ) or the full report.

9.2.1 Nonconformances noted in the report should be addressed by the supplier, by providing either an action plan or a justification for acceptance. The justification should include countermeasures in place and a risk characterization per SEMI S10.

SEMI S2-0818E © SEMI 1991, 2018 16

9.3 Seismic Information — Refer to § 19 of this Document.

9.4 Environmental Documentation — The manufacturer should provide the user with the following environmental documentation as applicable:

9.4.1 Energy consumption information, including idle, average, and peak operating conditions, for the manufacturer’s most representative (‘baseline’) process.

9.4.2 Mass balance, including idle, average, and peak operating conditions, for the manufacturer’s most representative (‘baseline’) process.

25: The mass balance may include resource consumption rates, chemical process efficiencies, wastewater effluent and air emission characterization, solid and hazardous waste generation (quantity and quality), and by-products.

9.4.3 Information regarding routes of unintended release (of effluents, wastes, emissions, and by-products) and methods and devices to monitor and control such releases. This should include information on features to monitor, prevent, and control unintended releases (see § 21.2.4 ).

9.4.4 Information regarding routes of intended release (of effluents, wastes, and emissions) and features to monitor and control such releases (see § 21.2.5 ).

9.4.5 A list of items that become solid waste as a result of the operation, maintenance, and servicing of the equipment, and that are constructed of or contain substances whose disposal might be regulated (e.g., beryllium-containing parts, vapor lamps, mercury switches, batteries, contaminated parts, maintenance wastes).

9.5 Industrial Hygiene and Exhaust Ventilation Information — Refer to §§ 22 through 27 of this Document and to SEMI S6.

26: Documentation criteria appear in various locations in SEMI S6. In SEMI S6-0707, these include ¶ 7.2.3 3.2, ¶ 7.7.3.4.1, § 8, § 9, Appendix 2, Appendix 3, Appendix 4, Appendix 5, and Appendix 6.

9.6 Manuals

9.6.1 The supplier should provide the user with manuals based on the originally intended use of the equipment. The manuals should describe the scope and normal use of the equipment, and provide information to enable safe facilitization, operation, maintenance, and service of the equipment.

9.6.2 The manuals should conform to SEMI S13.

27: Fire suppression agents, and chemicals used to test fire detection or suppression systems, fall under the MSDS provisions of SEMI S13 when they are provided with the equipment.

28: Hazardous energies within fire detection or suppression systems fall under the hazardous energy control provisions of SEMI S13 when fire detection or suppression systems are provided with the equipment.

9.6.3 In addition to the provisions of SEMI S13, the manuals should include:

specific written instructions on routine Type 4 tasks, excluding troubleshooting (refer to § 13.3 );

instructions for energy isolation (‘lockout/tagout’) (refer to § 17.2 );

description of the emergency off (EMO) and interlock functions;

a list of hazardous materials (e.g., lubricants, cleaners, coolants) required for maintenance, ancillary equipment or peripheral operations, including anticipated change-out frequency, quantity, and potential for contamination from the process;

a list of items that become solid waste as a result of the operation, maintenance, and servicing of the equipment, and that are constructed of or contain substances whose disposal might be regulated (e.g., beryllium-containing parts, vapor lamps, mercury switches, batteries, contaminated parts, maintenance wastes);

maintenance and troubleshooting procedures needed to maintain the effectiveness of safety design features or devices (i.e., engineering controls); and

instructions for proper use, maintenance, and inspection of lifting equipment supplied by the SME supplier, including any guidance on specific inspection intervals. For lifting equipment specified or recommended, but

17 SEMI S2-0818E © SEMI 1991, 2018

not supplied, by the SME supplier, the documentation provided by the SME supplier should specify that such instructions be obtained by the user from its lifting equipment supplier.

9.6.4 Information should be provided regarding potential routes of unintended releases (see § 21.2.4 ).

9.6.5 Recommended decontamination and decommissioning procedures should be provided in accordance with SEMI S12, and should include the following information:

identity of components and materials of construction, in sufficient detail to support recycling, refurbishment, and reuse decisions (see § 8.5.3 ); and

residual hazardous materials, or parts likely to become contaminated with hazardous materials, that may be in the equipment prior to decommissioning.

29: It is recommended that the manual state that changes to the typical process chemistry or to the equipment could alter the anticipated environmental impact.

9.6.6 Maintenance Procedures with Potential Environmental Impacts — The supplier’s recommended maintenance procedures should:

identify procedural steps during which releases might occur, and the nature of the releases; and

identify waste characteristics and methods to minimize the volume of effluents, wastes, or emissions generated during maintenance procedures.

9.7 Fire Protection Documentation — The equipment supplier should provide:

a summary fire protection report as described in § 14.3 ;

descriptions of optional fire risk mitigation features (see § 14.3.2 );

30: It is recommended that this be provided prior to purchase.

fire detection system operations, maintenance, and test manuals;

fire suppression system operations, maintenance, and test manuals;

acceptance documents provided by licensed designers and installers (see ¶¶ 14.5.1.12 and 14.5.2.16 ); and

a list of any special apparatus needed to test the fire detection or suppression features of the equipment. The list should note whether the apparatus is included with the equipment, or is sold separately.

10 Hazard Alert Labels10.1 Where it is impractical to eliminate hazards through design selection or to adequately reduce the associated risk with safety or warning devices, hazard alert labels should be provided to identify and warn against hazards.

10.2 Labels should be durable and suitable for the environment of the intended use.

10.3 Labels should conform to SEMI S1.

EXCEPTION: Some hazard label formats and content are dictated by law (e.g., laser labeling and chemical hazard communication labeling in certain countries of use) and may not conform to SEMI S1.

11 Safety Interlock Systems11.1 This section covers safety interlocks and safety interlock systems.

31: If a fire detection or suppression system is provided with the equipment, see § 14 for additional information.

11.2 Where appropriate, equipment should use safety interlock systems that protect personnel, facilities, and the community from hazards inherent in the operation of the equipment.

32: Safety critical parts whose primary function is to protect the equipment (e.g., circuit breakers, fuses) are typically not considered to be safety interlocks.

11.3 Safety interlock systems should be designed such that, upon activation of the interlock, the equipment, or relevant parts of the equipment, is automatically brought to a safe condition.

SEMI S2-0818E © SEMI 1991, 2018 18

33: Timing is relevant to risk; a safe condition includes bringing the equipment to a safe state before the hazard can be accessed by personnel.

11.4 Upon activation, the safety interlock should alert the operator immediately.

EXCEPTION: Alerting the operator is not expected if a safety interlock triggers the EMO circuit (see §  12 ) or otherwise removes power to the user interface.

34: An explanation of the cause is preferred upon activation of a safety interlock.

11.5 Safety interlock systems should be fault-tolerant and designed so that the functions or set points of the system components cannot be altered without disassembling, physically modifying, or damaging the device or component.

EXCEPTION: Components or circuits with adjustable set points or trip functions may be used in safety interlock systems if access is limited by requiring a deliberate action, such as using a tool or special keypad sequences, to access the adjustable devices or to adjust the devices. The justification for the adjustability of the interlock components or circuits should be included in the equipment evaluation report and equipment documentation.

35: The intent is to limit access to the adjustable setpoints to properly trained maintenance and service personnel.

36: This section does not address the defeatability of safety interlocks. See § 11.6.1 for additional information.

11.5.1 Interlock and EMO circuits should remove hazardous energies by de-energizing rather than energizing. Shunt trips are an example of components that do not operate by de-energizing.

EXCEPTION 1: This criterion is considered to be met if a) one part of a redundant circuit operates by de-energizing and the second part operates by energizing, or b) the monitoring circuit operates by energizing as long as the monitored circuit operates by de-energizing.

EXCEPTION 2: Earth Leakage (ground fault) sensing components (e.g., GFI, GFCI, RCD and ELB) often work by energizing within the components and are acceptable if a) the earth leakage sensing component(s) meets ¶ 13.4.3 and b) the rest of the earth leakage interlock or EMO circuit operates by de-energizing.

11.6 Electromechanical devices and components are preferred. Solid-state devices and solid-state components may be used, provided that the safety interlock system, or relevant parts of the system, are evaluated for suitability for use in accordance with appropriate standard(s). The evaluation for suitability should take into consideration abnormal conditions such as overvoltage, undervoltage, power supply interruption, transient overvoltage, ramp voltage, electromagnetic susceptibility, electrostatic discharge, thermal cycling, humidity, dust, vibration, and jarring.

EXCEPTION: Where the severity of a reasonably foreseeable mishap is deemed to be Minor per SEMI S10, a software-based interlock may be considered suitable.

37: Where a safety interlock is provided to safeguard personnel from severe or catastrophic harm as categorized by SEMI  S10, consideration of positive-opening type switches is recommended.

38: Evaluation for suitability for use may also include reliability, self-monitoring, and redundancy as addressed under standards such as NEMA® 24 ICS 1.1 and UL 991.

39: Solid-state devices include operational amplifiers, transistors, and integrated circuits.

11.6.1 If a programmable safety controller or FECS is used, the design should conform to the Safety Interlock Design criteria in SEMI S22.

39: ¶ 13.4.3 states additional assessment criteria for safety-related components and assemblies.

40: A FECS is a subsystem of a (PES) Programmable Electronic System. IEC 61508 is the preferred standard for complex PES.

41: Related Information 13 provides additional information on applications of FECS design.

42: The Safety Interlock Design criteria are in § 13.7.3 of the 0715 version of S22.

11.7 The safety interlock system should be designed to minimize the need to override safety interlocks during maintenance activities.

24 NEMA trademark is owned by National Electrical Manufacturers Association.

19 SEMI S2-0818E © SEMI 1991, 2018

11.7.1 Safety interlocks that safeguard personnel during operator tasks should not be defeatable without the use of a tool.

11.7.2 When maintenance access is necessary to areas protected by interlocks, defeatable safety interlocks may be used, provided that they require an intentional operation to bypass.

11.7.2.1 Upon exiting or completing the maintenance mode, all safety interlocks should be automatically restored.

11.7.2.2 If a safety interlock is defeated, the maintenance manual should identify administrative controls to safeguard personnel or to minimize the hazard.

11.8 The restoration of a safety interlock should not initiate equipment operation or parts movement where this can give rise to a hazardous condition.

11.9 Switches and other control device contacts should be connected to the ungrounded side of the circuit so that a short circuit to ground does not result in the interlocks being satisfied.

11.10 Where a hazard to personnel is controlled through the use of an enclosure, the enclosure should either: require a tool to gain access and be labeled regarding the hazard against which it protects personnel; or be interlocked. In addition to enclosures, physical barriers at the point of hazard should be included where inadvertent contact is likely.

43: Where the removal of a cover exposes a hazard, consider additional labels. See § 10 for guidance.

12 Emergency Shutdown12.1 The equipment should have an ‘emergency off’ (EMO) circuit. The EMO actuator (e.g., button), when activated, should place the equipment into a safe shutdown condition, without generating any additional hazard to personnel or the facility.

EXCEPTION 1: An EMO circuit is not needed for equipment rated 2.4 kVA or less, where the hazards are only electrical in nature, provided that the main disconnect meets the accessibility provisions of § 12.5.2 and that the effect of disconnecting the main power supply is equivalent to activating an EMO circuit.

EXCEPTION 2: Assemblies that are not intended to be used as stand-alone equipment, but rather within an overall integrated system, and that receive their power from the user’s system, are not required to have an emergency off circuit. The assembly’s installation manual should provide clear instructions to the equipment installer to connect the assembly to the integrated system’s emergency off circuit.

44: It is recommended that the emergency off function not reduce the effectiveness of safety devices or of devices with safety-related functions (e.g., magnetic chucks or braking devices) necessary to bring the equipment to a safe shutdown condition effectively.

45: If a fire detection or suppression system is provided with the equipment, see § 14 for additional information.

12.1.1 If the supplier provides an external EMO interface on the equipment, the supplier should include instructions for connecting to the interface.

12.2 Activation of the emergency off circuit should de-energize all hazardous voltage and all power greater than 240 volt-amps in the equipment beyond the main power enclosure.

EXCEPTION 1: A nonhazardous voltage EMO circuit (typically 24 volts) and its supply may remain energized.

EXCEPTION 2: Safety related devices (e.g., smoke detectors, gas/water leak detectors, pressure measurement devices, etc.) may remain energized from a nonhazardous power source.

EXCEPTION 3: A computer system performing data/alarm logging and error recovery functions may remain energized, provided that the energized breaker(s), receptacle(s), and each energized conductor termination are clearly labeled as remaining energized after EMO activation. Hazardous energized parts that remain energized after EMO activation should be insulated or guarded to prevent inadvertent contact by personnel.

EXCEPTION 4: Multiple units mounted separately with no shared hazards and without interconnecting circuits with hazardous voltages, energy levels or other hazardous conditions may have:

separate sources of power and separate supply circuit disconnect means if clearly identified, or

separate EMO circuits, if they are clearly identified.

SEMI S2-0818E © SEMI 1991, 2018 20

12.2.1 The EMO circuit should not include features that are intended to allow it to be defeated or bypassed.

12.2.2 The EMO circuit should consist of electromechanical components.

EXCEPTION 1: Solid-state devices and components may be used, provided the system or relevant parts of the system are evaluated and found suitable for use. The components should be evaluated and found suitable considering abnormal conditions such as over voltage, under voltage, power supply interruption, transient over voltage, ramp voltage, electromagnetic susceptibility, electrostatic discharge, thermal cycling, humidity, dust, vibration and jarring. The final removal of power should be accomplished by means of electromechanical components.

EXCEPTION 2: FECS may be used in conjunction with electromechanical or solid-state devices and components provided the FECS meets the Safety Interlock Design criteria in SEMI S22. The final removal of power should be accomplished by means of electromechanical components.

46: ¶ 13.4.3 states additional assessment criteria for safety-related components and assemblies.

47: A FECS is a subsystem of a PES. IEC 61508 is the preferred standard for complex PES.

12.2.3 All EMO circuits should be fault-tolerant.

12.2.4 Resetting the EMO switch should not re-energize circuits, equipment, or subassemblies.

12.2.5 The EMO circuit should shut down the equipment by de-energizing rather than energizing control components.

12.2.6 The EMO circuit should require manual resetting so that power cannot be restored automatically.

12.3 The emergency off button should be red, mushroom shaped, and self-latching. A yellow background for the EMO should be provided.

12.4 All emergency off buttons should be clearly labeled as ‘EMO,’ ‘Emergency Off,’ or the equivalent and should be clearly legible from the viewing location. The label may appear on the button or on the yellow background.

12.5 Emergency off buttons should be readily accessible from operating and regularly scheduled maintenance locations and appropriately sized to enable activation by the heel of the palm.

12.5.1 Emergency off buttons should be located or guarded to minimize accidental activation.

12.5.2 No operation or regularly scheduled maintenance location should require more than 3 m (10 ft.) travel to an EMO button.

12.5.3 The person actuating or inspecting the EMO switch assembly should not be exposed to hazards with a SEMI S10 risk of Medium or greater. Examples of hazards that could have such risk are:

contacting energized electrical parts,

contacting moving machinery,

contacting surfaces that are at excessively high or low temperatures, and

limited or poor access causing impacts, tripping or falling during rapid movement during an emergency.

12.6 See § 13.5 for additional EMO guidelines when EMOs are used with UPSs.

13 Electrical Design13.1 This section covers electrical and electronic equipment that use hazardous voltages.

13.2 Types of Electrical Work — The following are the four types of electrical work defined by this Safety Guideline:

Type 1 — Equipment is fully de-energized.

Type 2 — Equipment is energized. Energized circuits are covered or insulated.

48: Type 2 work includes tasks where the energized circuits are or can be measured by placing probes through suitable openings in the covers or insulators.

21 SEMI S2-0818E © SEMI 1991, 2018

Type 3 — Equipment is energized. Energized circuits are exposed and inadvertent contact with uninsulated energized parts is possible. Potential exposures are no greater than 30 volts rms, 42.4 volts peak, 60 volts DC or 240 volt-amps in dry locations.

Type 4 — Equipment is energized. Energized circuits are exposed and inadvertent contact with uninsulated energized parts is possible. Potential exposures are greater than 30 volts rms, 42.4 volts peak, 60 volts DC, or 240 volt-amps in dry locations. Potential exposures to radio-frequency currents, whether induced or via contact, exceed the limits in Table AA3-2.5.1.1 Table A3-1 of Appendix APPENDIX 3.

13.3 Energized Electrical Work — The supplier should design the equipment to minimize the need to calibrate, modify, repair, test, adjust, or maintain equipment while it is energized, and to minimize work that must be performed on components near exposed energized circuits. The supplier should move as many tasks as practical from category Type 4 to Types 1, 2, or 3. Routine Type 4 tasks, excluding troubleshooting, should have specific written instructions in the maintenance manuals. General safety procedures (e.g., wearing appropriate Personal Protective Equipment and establishing barriers) for troubleshooting, including Type 4 work, should be provided.

13.4 Electrical Design — Equipment should conform to the appropriate international, regional, national or industry product safety requirements.

13.4.1 Nonconductive or grounded conductive physical barriers should be provided:

Where it is necessary to reach over, under, or around, or in close proximity to hazards.

Where dropped objects could cause shorts or arcing.

Where failure of liquid fittings from any part of the equipment would result in the introduction of liquid into electrical parts.

Over the line side of the main disconnect.

Where maintenance or service tasks on equipment in dry locations are likely to allow inadvertent contact with uninsulated energized parts containing either: potentials greater than 30 volts rms, 42.4 volts peak, or 60 volts DC; or power greater than 240 volt-amps.

49: A dry location can be considered to be one that is not normally subject to dampness or wetness.

50: Removable nonconductive and noncombustible covers are preferred.

13.4.2 Where test probe openings are provided in barriers, the barriers should be located, and the probe openings should be sized, to prevent inadvertent contact with adjacent energized parts, including the energized parts of the test probes.

13.4.3 Where failure of components and assemblies could result in a risk of electric shock, fire, or personal injury, those components and assemblies should be certified by an accredited testing laboratory and used in accordance with the manufacturer’s specifications, or otherwise evaluated to the applicable standard(s).

13.4.4 Electrical wiring for power circuits, control circuits, grounding (earthing) and grounded (neutral) conductors should be color coded according to appropriate standard(s) per § 13.4 , or labeled for easy identification at both ends of the wire. Where color is used for identification, it is acceptable to wrap conductor ends with appropriate colored tape or sleeving; the tape or sleeving should be reliably secured to the conductor.

EXCEPTION 1: Internal wiring on individual components (e.g., motors, transformers, meters, solenoid valves, power supplies).

EXCEPTION 2: Flexible cords.

EXCEPTION 3: Nonhazardous voltage multiconductor cables (e.g., ribbon cables).

EXCEPTION 4: When proper color is not available for conductors designed for special application (e.g., high-temperature conductors used for furnaces and ovens).

13.4.5 Grounding (earthing) conductors and connectors should be sized to be compatible in current rating with their associated ungrounded conductors according to appropriate standard(s) per § 13.4 .

13.4.6 Electrical enclosures should be suitable for the environment in which they are intended to be used.

SEMI S2-0818E © SEMI 1991, 2018 22

13.4.7 Enclosure openings should safeguard against personnel access to un-insulated parts energized to a hazardous voltage or hazardous electrical power. Compliance to this criteria should be demonstrated by compliance to enclosure opening criteria in SEMI S22.

13.4.8 Top covers of electrical enclosures should be designed and constructed to significantly reduce the risk of objects falling into the enclosure. Compliance to this criteria should be demonstrated by compliance to the enclosure opening criteria in SEMI S22.

13.4.9 The short circuit current rating of the equipment or its industrial control panel, for each supply circuit from the facility to the equipment, should be identified in the equipment installation instructions.

13.4.10 The equipment should be provided with main overcurrent protection devices and main disconnect devices rated for at least 10,000 rms symmetrical amperes interrupting capacity (AIC).

51: Some facilities may require higher AIC ratings due to electrical distribution system design.

EXCEPTION: Cord- and plug-connected single phase equipment, rated no greater than 240 volts line-to-line/150 volts line-to-ground and no greater than 2.4 kVA, may have overcurrent protection devices with interrupting capacity of at least 5,000 rms symmetrical AIC.

13.4.11 Equipment should be designed to receive incoming electrical power from the facility to a single feed location that terminates at the main disconnect specified in § 13.4.10 . This disconnect, when opened, should remove all incoming electrical power in the equipment from the load side of the disconnect. The disconnect should also have the energy isolation (‘lockout’) capabilities specified in § 17 .

EXCEPTION 1: Equipment with more than one feed should be provided with provisions for energy isolation (lockout) for each feed and be marked with the following text or the equivalent at each disconnect: “WARNING: Risk of Electric Shock or Burn. Disconnect all [number of feed locations] sources of supply prior to servicing.” It is preferred that all of the disconnects for the equipment be grouped in one location.

EXCEPTION 2: Multiple units mounted separately with no shared hazards and without interconnecting circuits with hazardous voltages, energy levels or other potentially hazardous conditions may have:

separate sources of power and separate supply circuit disconnect means, if they are clearly identified; or

separate EMO circuits, if they are clearly identified.

13.4.12 A permanent nameplate listing the manufacturer’s name, machine serial number, supply voltage, number of phases, frequency, short circuit current rating of the equipment or its industrial control panel, and full-load current should be attached to the equipment where plainly visible after installation. Where more than one incoming supply circuit is to be provided, the nameplate(s) should state the above information for each circuit.

52: Additional nameplate information may be required depending on the location of use.

13.5 Uninterruptable Power Supplies (UPSs) — This section applies to UPSs with outputs greater than: 30 volts rms, 42.4 volts peak; 60 volts DC; or 240 volt-amps.

13.5.1 Whenever a UPS is provided with the equipment, its location and wiring should be clearly described within the installation and maintenance manual.

13.5.2 Power from the UPS should be interrupted when any of the following events occur:

the emergency off actuator (button) is pushed; or

the main equipment disconnect is opened; or

the main circuit breaker is opened.

EXCEPTION: Upon EMO activation, the UPS may supply power to the EMO circuit, safety related devices, and data/alarm logging computer systems as described in the exception clauses of § 12.2 .

13.5.3 The UPS may be physically located within the footprint of the equipment provided that the UPS is within its own enclosure and is clearly identified.

13.5.4 The UPS should be certified by an accredited testing laboratory and be suitable for its intended environment (e.g., damp location, exposure to corrosives).

23 SEMI S2-0818E © SEMI 1991, 2018

13.5.5 The UPS wiring should be identified as ‘UPS Supply Output’ or equivalent at each termination point where the UPS wiring can be disconnected.

13.6 Electrical Safety Tests

13.6.1 Equipment connected to the facility branch circuit with a cord and plug should not exhibit surface leakage current greater than 3.5 milliampere (mA) as determined by testing completed in accordance with ‘Leakage Current Test for Cord-and-Plug Equipment’ in SEMI S22, Testing section.

EXCEPTION: Equipment with leakage current exceeding 3.5 mA is acceptable if documentation is provided to substantiate that the equipment is fully compliant with an applicable product safety standard that explicitly permits a higher leakage current.

13.6.2 Equipment protective grounding circuits should have a measured resistance of one-tenth (0.1) ohm or less as determined by testing in accordance with ‘Earthing Continuity and Continuity of the Protective Bonding Circuit Test’ in SEMI S22.

13.7 Equipment in which flammable liquids or gases are used should be assessed to determine if additional precautions (e.g., purging) in the electrical design are necessary.

53: NFPA 497 and EN 1127-1 provide methods for making this assessment.

14 Fire Protection14.1 Overview — This section applies to fire hazards that are internal to the equipment.

14.1.1 This section provides minimum safety considerations for fire protection designs and controls on the equipment.

14.1.2 This section also provides minimum considerations for fire detection and suppression systems when provided with the equipment.

54: Detailed guidance on fire risk assessment and mitigation for semiconductor manufacturing equipment is provided in SEMI S14.

14.2 Risk Assessment

14.2.1 A documented risk assessment should be performed or accepted by a party qualified to determine and evaluate fire hazards and the potential need for controls. The risk assessment should consider normal operations and reasonably foreseeable single-point failures within the equipment. It should not consider exposure to fire or external ignition sources not within the specified use environment.

55: This risk assessment can be combined with the overall hazard analysis performed for this guideline, provided the risk assessor has the required professional expertise to perform risk assessments for fire hazards. SEMI S7 describes qualifications for such an assessor.

14.2.2 If an accurate risk assessment depends on the user’s adherence to specified procedures or conditions of use, the supplier should describe such procedures or conditions and state their importance.

14.2.3 SEMI S14 should be used to assess and report risks to property and the environment.

14.3 Reporting

14.3.1 A summary report should be provided to the user. The summary should include the following characterizations, per SEMI S10, for each residual fire hazard identified:

the assigned Severity;

the assigned Likelihood; and

the resulting Risk Category.

14.3.2 Optional fire risk reduction features should be described in the pre-purchase information provided to the user.

14.3.3 The scope and effectiveness of the means of fire risk reduction should also be identified and reported, including the expected risk reduction (as described in § 14.3.1 ).

SEMI S2-0818E © SEMI 1991, 2018 24

14.3.4 If, due to fire hazards within the equipment, thermal or non-thermal (e.g., smoke) damage is possible outside of the equipment, then this possibility should be reported to the user. This report should include a qualitative description of the foreseen scenario.

14.4 Fire Risk Reduction (Other than Detection and Suppression)

14.4.1 Materials of Construction — Equipment should be constructed of noncombustible materials wherever reasonable. If process chemicals do not permit the use of noncombustible construction, then the equipment should be constructed of materials, suitable for the uses and compatible with the process chemicals used, that contribute least to the fire risk.

56: Some regional codes (e.g., Uniform Fire Code) may require construction with noncombustible materials.

14.4.1.1 The flowchart in Appendix APPENDIX 4 may be used for the selection of materials of construction for equipment.

14.4.1.2 Any portion of equipment that falls within the scope of SEMI F14 (Guide for the Design of Gas Source Equipment Enclosures) should be designed in accordance with that Guide.

14.4.2 Elimination of Process Chemical Hazards — The option of substituting nonflammable process chemicals for flammable process chemicals should be considered.

14.4.3 Engineering Controls

14.4.3.1 Fire risks resulting from process chemicals may be reduced using engineering controls (e.g., preventing improper chemical mixing, preventing temperatures from reaching the flash point).

14.4.3.2 Fire risks resulting from materials of construction may be reduced using engineering controls (e.g., non-combustible barriers that separate combustible materials of construction from ignition sources).

14.4.3.3 Equipment power and chemical sources that present unacceptable fire risks should be interlocked with the fire detection and suppression systems to prevent start-up of the equipment or delivery of chemicals when the fire detection or suppression is inactive.

57: Some jurisdictions require interlocking.

58: Refer to § 6.5 for criteria for acceptability.

14.4.3.4 Controlling smoke by exhausting it (using the supplier-specified equipment exhaust) from the cleanroom may be used to reduce fire risks from the generation of products of combustion.

59: Where exhaust is used to control the risk of smoke and there is a risk of flame propagation, see §  14.5 regarding combining this risk reduction method with detection or suppression.

60: Controlling smoke may be sufficient when smoke is the only consequence (e.g., smoldering components that generate smoke).

61: For controlling smoke to be effective, the smoke must be removed not only from the equipment, but also from the cleanroom. This is typically accomplished by using ducted exhaust.

62: The use of exhaust to remove smoke may be subject to regulations, such as building and fire codes.

63: The use of exhaust to remove smoke may create hazards within the exhaust system. Therefore, a description of the expected discharge (i.e., anticipated air flow rate, temperature, and rate of smoke generation) into the exhaust system may be important information for installation of equipment.

14.5 Fire Detection and Suppression Systems

14.5.1 Fire Detection — The following criteria apply to any fire detection system determined to be appropriate for fire protection by the fire risk assessment:

64: Heat detectors, smoke sensing devices, and other devices used solely for monitoring equipment status may not need to meet these requirements. Some local jurisdictions, however, may require that all smoke detectors be connected to building systems and be compliant with all applicable fire alarm codes.

14.5.1.1 The fire detection system, which includes detectors, alarms and their associated controls, should be certified by an accredited testing laboratory and suitable for the application and for the environment in which it is to be used.

25 SEMI S2-0818E © SEMI 1991, 2018

65: Such certifications typically require that the components of fire detection systems are readily identifiable and distinguishable from other components in the equipment.

14.5.1.2 The fire detection, alarm and control system should be installed in accordance with the requirements of the certification in § 14.5.1.1 , and in accordance with requirements of the appropriate international or national codes or standards (e.g., NFPA 72).

14.5.1.3 The fire detection system should be capable of interfacing with the facility’s alarm system. It may be preferable for the equipment supplier to specify the location and performance of detectors, but not provide them, so that the user may better integrate the detection in the equipment with that in the facility. This alternative should be negotiated explicitly with the user.

14.5.1.4 The fire detection system should activate alarms audibly and visually at the equipment.

14.5.1.4.1 The audible alarm should be capable of being heard from each operation or maintenance/service location in which personnel are inside or within 2 meters of a portion of the equipment that includes fire detection. This may require more than one audible device.

14.5.1.4.1.1 The audible alarm should be at least 90 dB and 5 dB over maximum equipment noise level prior to the start of the alarm. Conformance to this criterion may be determined by measuring sound levels at representative locations.

66: Upper limits for the sound levels from alarms are imposed by various standards and regulations. At the time of publication of this Document, the lowest of which the originating Task Force was aware is 110 dBA, imposed by NFPA 72-2013, National Fire Alarm and Signaling Code, paragraph 18.4.1.2.

67: Some fire codes require that the audible alarm should be capable of being distinct and differentiable from the building fire alarm audible systems.

68: It is recommended that the documents provided to the end user should include instructions to verify the audible alarm is distinguishable above the ambient noise end-use environment.

14.5.1.4.2 The visual alarms should be capable of being seen from outside the equipment at all entrances to locations that include fire detection. This may require more than one visual device.

69: For protected equipment spaces that can be fully entered, visual alarms inside the equipment may be considered.

14.5.1.5 Manual activation capability for the fire detection system should be considered, for the purpose of providing notification to a constantly attended location.

14.5.1.5.1 It is recommended that no operation or regularly scheduled maintenance location require more than 15 m (50 ft.) travel to a manual activation device. More than one manual activation device may be needed to achieve this.

14.5.1.6 Activation of trouble or supervisory conditions should result in all of the following:

notification of the operator;

allowing the completion of processing of substrates in the equipment;

prevention of processing of additional substrates until the trouble or supervisory condition is cleared; and

providing, through an external interface, a signal to the facility monitoring system or a constantly attended location.

70: Some local jurisdictions require that such alarms signal the building/facility fire alarm systems.

14.5.1.7 The fire detection system should be capable of operating at all times, including when the equipment is inoperable (e.g., equipment controller problems) or in maintenance modes (e.g., some or all of the equipment’s hazardous energies are isolated (‘locked out’). For the purpose of this section, ‘inoperable’ includes the equipment states after an EMO is activated and after the equipment has had its hazardous energies isolated (i.e., has been ‘locked out’). Therefore, the detection system should not require hazardous voltages (e.g., line alternating current) to operate anything other than the equipment within the detection system’s control enclosure. Sensors and other devices outside the detection system’s control enclosure should not require hazardous voltage.

EXCEPTION: Operability is not required during maintenance of the fire detection system.

SEMI S2-0818E © SEMI 1991, 2018 26

14.5.1.7.1 Power at a hazardous voltage may be supplied to the detection system controller enclosure after the equipment EMO is activated or after the equipment has had its hazardous energies isolated only if the wiring providing the hazardous voltage is separated from other wiring and is suitably labeled.

14.5.1.7.2 If the hazardous voltage supply to the detection system controller is not disconnected by the energy isolation method that removes the other hazardous voltages from the equipment, there must also be separate hazardous energy isolation capability for the hazardous voltage supplies to the detection system controller enclosure.

14.5.1.8 A battery or other regulatory agency acceptable emergency power alternative, capable of sustaining the detection system for 24 hours, should be provided.

71: Back-up power must be provided in accordance with local regulations. The requirements for back-up power vary among jurisdictions.

14.5.1.9 The fire detection system should remain active following EMO activation.

14.5.1.10 There may be cases where the internal power supply for a detection system cannot supply power for the full length of extended maintenance procedures (i.e., procedures longer than the expected duration of the back-up power supply). In such cases, the supplier should provide written procedures for either removing the fire hazard or safely supplying power to the fire detection system.

14.5.1.11 Activation of the fire detection system should shut down the equipment within the shortest time period that allows for safe equipment shutdown. This includes shutdown of any fire-related hazard source that could create additional fire risks for the affected module or component.

72: See §§ 14.4.3.3 and 14.4.3.4 for related provisions.

EXCEPTION 1: A non-recycling, deadman abort switch is acceptable on detection systems that are used for equipment shutdown, but not on those used for activation of a suppression system.

EXCEPTION 2: Activation of the fire detection system should not remove power from fire and safety systems.

14.5.1.12 Shutdown or failure of a fire detection or suppression system need not interrupt the processing of product within the equipment by immediately shutting down the equipment, but should prevent additional processing until the fire detection or suppression is restored. Software or hardware may be used for this function.

14.5.1.13 The equipment design and configuration should not prevent licensed parties from certifying the design and installation of fire detection systems.

73: This is not meant to suggest installation by licensed parties; however, some jurisdictions require fire detection and suppression system installers to be licensed as specified by the jurisdiction.

14.5.2 Fire Suppression — The following criteria apply to any fire suppression system determined to be appropriate by the fire risk assessment.

74: As a fire detection system is generally required to provide the initiating sequence for the suppression system, it is the intention of this guideline that this be the same fire detection system described in § 14.5.1 .

14.5.2.1 The fire suppression system, which includes nozzles, actuators, and their associated controls, should be certified by an accredited testing laboratory and suitable for the application and for the environment in which it to be used.

75: Such certifications typically require that the components of fire suppression systems are readily identifiable and distinguishable from other components in the equipment. This includes adequate labeling of piping.

14.5.2.2 The fire suppression agent should be accepted for the application by an accredited testing laboratory. The suppression agent selection process should include an evaluation of the amount and storage location of the suppression agent and of potential damage to a cleanroom and the environment. The least damaging effective agent should be selected. If more than one agent is effective, the options should be specified to the user so that the user may specify which agent should be provided with the equipment. The supplier should also specify if the user may provide the agent.

14.5.2.3 The fire suppression agent and delivery system should be designed and installed in accordance with the appropriate international or national standard (e.g., NFPA 12, NFPA 13, NFPA 2001). It may be preferable for the equipment supplier to specify the location and performance of suppression system components, but not provide

27 SEMI S2-0818E © SEMI 1991, 2018

them, so that the user may better integrate the suppression in the equipment with that in the facility. This alternative should be negotiated explicitly with the user.

14.5.2.4 The assessment of the equipment to SEMI S2 should include the risks associated with the suppression systems.

76: This includes risks (e.g., chemical exposure, noise, and asphyxiation) introduced by the incorporation of the suppression system.

14.5.2.5 Activation of the fire suppression system should alarm audibly and visually at the equipment. This may be done by the same system that initiates activation.

14.5.2.5.1 The audible alarm should be capable of being heard from each operation or maintenance/service location in which personnel are inside or within 2 meters of a portion of the equipment where fire suppression agent is to be discharged. This may require more than one audible device.

14.5.2.5.1.1 The audible alarm should be at least 90 dB and 5 dB over maximum equipment noise level prior to the start of fire suppression discharge. Conformance to this criterion may be determined by measuring sound levels at representative locations.

77: Upper limits for the sound levels from alarms are imposed by various standards and regulations. At the time of publication of this Document, the lowest of which the originating Task Force was aware is 110 dBA, imposed by NFPA 72-2013, National Fire Alarm and Signaling Code, paragraph 18.4.1.2.

78: Some fire codes require that the audible alarm should be capable of being distinct and differentiable from the building fire alarm audible systems.

79: It is recommended that the documents provided to the end user should include instructions to verify the audible alarm is distinguishable above the ambient noise end-use environment.

14.5.2.5.2 The visual alarms should be capable of being seen from outside the equipment at all protected space entrance locations where fire suppression agent is to be discharged. This may require more than one visual device.

80: For protected equipment spaces that can be fully entered, visual alarms inside the equipment may be considered.

14.5.2.6 If the discharge is likely to present a risk to personnel, the alarm should provide adequate time to allow personnel to avoid the hazard of the agent discharge.

14.5.2.6.1 If there is a confined space in the equipment, the asphyxiation hazard posed by the suppression system should be assessed.

14.5.2.7 The fire suppression system should be capable of operating at all times, including when equipment is inoperable and during equipment maintenance.

81: For the purpose of this section, ‘inoperable’ includes the equipment state after the EMO is activated.

EXCEPTION: Most suppression systems contain sources of hazardous energy. These sources should be capable of being isolated (i.e., ‘locked out’) to protect personnel.

14.5.2.8 The fire suppression system should remain active following EMO activation.

14.5.2.9 There may be cases where the internal power supply for a suppression system cannot supply power for the full length of extended maintenance procedures (i.e., procedures longer than the expected duration of the back-up power supply). In such cases, the supplier should provide written procedures for either removing the fire hazard or safely supplying power to the fire suppression system.

14.5.2.10 Allowances can be made to provide for the deactivation of an automatic discharge of the suppression system when in the maintenance mode. Such deactivation switches should be supervised (i.e., if the suppression system is deactivated, there should be an indication to the user and the resumption of production in the equipment should be prevented).

82: Hazardous energies associated with the fire suppression system may be isolated (i.e., ‘locked out’) using an energy isolation procedure (see § 17 ) during equipment maintenance.

83: The permissibility of deactivation of suppression systems varies among jurisdictions.

SEMI S2-0818E © SEMI 1991, 2018 28

14.5.2.11 A back-up power supply, capable of sustaining the suppression system for 24 hours, should be included where the suppression system requires independent power from the detection system used to activate the suppression.

84: The requirements for back-up power vary among jurisdictions.

14.5.2.12 The fire suppression system should be capable of interfacing with the facility’s alarm system. This may be done via the fire detection system.

14.5.2.13 Activation of the fire suppression system should shut down the equipment within the shortest time period that allows for safe equipment shutdown.

85: See §§ 14.4.3.3 and 14.4.3.4 for related provisions.

EXCEPTION: Activation of the fire suppression system should not remove power from fire and safety systems.

14.5.2.14 The fire suppression system should be capable of manual activation, which should shut down the equipment and activate an alarm signal locally and at a constantly attended location.

14.5.2.14.1 No operation or regularly scheduled maintenance location from which a location protected by fire suppression is visible should require more than 15 m (50 ft.) travel to a manual activation device. More than one manual activation device may be needed to achieve this.

14.5.2.15 The fire suppression system should be tested on a representative sample of the equipment. The test procedure should include a suppression agent discharge test, unless precluded for health or environmental reasons. This test may be performed at the equipment supplier’s or other similar facility, but should be performed under conditions that adequately duplicate any factors (e.g., equipment exhaust) that may reduce the effectiveness of the suppression. This representative sample need not be fully operational, but should duplicate those factors (e.g., exhaust, air flow) that could negatively affect the performance of the system.

14.5.2.16 Procedures for controlling access to the suppression agent source (e.g., protecting agent cylinders from disconnection by unauthorized personnel) should be provided.

14.5.2.17 The equipment design and configuration should not prevent licensed parties from certifying the design and installation of fire suppression systems.

86: This is not meant to suggest installation by licensed parties; however, some jurisdictions require fire detection and suppression system installers to be licensed as specified by the jurisdiction.

14.5.2.18 Installation of Piping for Fire Suppression Agent — The fire suppression piping system should be:

made from corrosion-resistant components,

designed to minimize water accumulation around components and control other conditions that promote corrosion, and

designed so mechanical inspections are easily performed.

14.5.2.19 Piping should be designed, installed, and tested to ensure that it is capable of containing the high pressures generated by the discharge of the suppression agent.

14.5.2.20 The supplier should provide information necessary for proper field installation of piping.

14.6 Warnings and Safe Work Practices — Warnings and safe work practices related to fire detection and suppression features of the equipment (e.g., restrictions on using open flames within range of active fire detection systems, hazardous stored energy in pressurized suppression systems) should be part of the documentation provided by the supplier.

14.7 Maintenance and Testing of Fire Detection and Suppression Systems — The equipment supplier should provide detailed maintenance and testing procedures for the fire systems provided with each piece of equipment. These procedures should include testing frequency, as well as details of special equipment required for testing.

14.7.1 Chemical generating test apparatus (e.g., canned smoke) should be avoided for cleanroom applications.

87: Information about UV/IR generating sources used for testing fire detection systems may require consideration of § 25 (Non-Ionizing Radiation).

29 SEMI S2-0818E © SEMI 1991, 2018

14.7.2 The maintenance testing procedure should include testing of the facility interface and verifying that all the equipment fire detection and suppression systems are functional.

14.7.3 The detection and suppression systems should be designed so that preventative maintenance of components does not degrade their performance (e.g., by resulting in displacement or destruction of sensors).

14.7.4 Supplier should document the sound pressure level generated during suppression agent discharge, if the test is performed.

14.7.5 Materials or procedures used for testing and maintenance of the fire detection and suppression system should not degrade the equipment’s ability to perform its intended function.

14.7.6 Suppliers should describe hazardous energies present in fire detection and suppression systems, and provide instructions for their proper isolation (see § 17.2 ).

14.8 Environmental — Suppliers should provide guidance to users regarding the impact on emissions of any fire suppression agents used in the equipment.

15 Process Liquid Heating Systems15.1 Refer to SEMI S3 for the minimum safety design considerations for process liquid heating systems.

88: SEMI S3 defines ‘process liquid’ as a substance that participates, while in the liquid state, in a chemical or physical reaction on the surface of a substrate as part of the manufacturing of semiconductor or flat panel devices and ‘process liquid heating system’ as a heating system comprised of the heater, its power and control systems, the vessel in which the liquid chemical is heater, and, if applicable, the heat transfer liquid and its associated piping.

89: See § 14 for fire protection risk assessment considerations for baths using combustible or flammable chemicals.

16 Ergonomics and Human Factors16.1 General — Ergonomics and human factors design principles should be incorporated into the development of equipment to identify and eliminate or mitigate ergonomics- and human factors-related hazards.

16.2 Provisions for Conformance — Equipment should be assessed to the guidelines set forth in SEMI S8. The Supplier Ergonomic Success Criteria (SESC; see SEMI S8), or the equivalent, should be used to document the assessment.

17 Hazardous Energy Isolation17.1 General

17.1.1 Lockable energy isolation capabilities should be provided for tasks that may result in contact with hazardous energy sources.

17.1.2 Where service tasks may be safely performed on subassemblies, energy isolation devices (e.g., circuit breakers, disconnect switches, manual valves) may be provided for the subassemblies for use as an alternative to shutting down the entire equipment system. The isolation devices should isolate all hazardous energy to the subassemblies and be capable of being locked in the position in which the hazardous energy is isolated.

17.1.3 The person actuating or inspecting an energy isolating device should not be exposed to serious risks of tripping or falling or of coming in contact with energized electrical parts, moving machinery, surfaces or objects operating at high temperatures, or other hazardous equipment.

90: Hazardous energies include electrical, stored electrical (e.g., capacitors, batteries), chemical, thermal/cryogenic, stored pressure (e.g., pressurized containers), suspended weight, stored mechanical (e.g., springs), generated pressure (e.g., hydraulics and pneumatics), and other sources that may lead to the risk of injury.

91: In order to minimize down-time and provide ease of use, it is preferred to have energy isolation devices located in the areas where maintenance or service is performed.

92: Energy isolation devices for incompatible hazardous energy sources (e.g., electrical and water, incompatible gases) are recommended to be separated.

93: Isolation of hazardous energy may include: de-energizing of hazardous voltage; stopping flow of hazardous production material (HPM); containing HPM reservoirs; depressurizing or containing HPM and pneumatic lines; de-energizing or totally

SEMI S2-0818E © SEMI 1991, 2018 30

containing hazardous radiation; discharging of residual energy in capacitors; stopping of hazardous moving parts; and shutting off hazardous temperature sources.

94: Energy isolation devices with integral locking capabilities are preferred, but may not be feasible or commercially available, in which case detachable lockout adapters may be used.

95: See § 14 for information on fire protection hazardous energies.

17.2 Installation and Maintenance Manuals

17.2.1 Installation and maintenance manuals should identify the types of hazardous energies within the equipment.

17.2.2 Installation and maintenance manuals should provide specific instructions for the equipment on how to:

shut down the equipment in an orderly manner;

locate and operate all the equipment’s energy isolating devices;

affix energy isolating (‘lockout/tagout’) devices;

relieve any stored energies;

verify that the equipment has actually been isolated and de-energized; and

properly release the equipment from its isolated state.

17.2.3 Where the manufacturer provides written maintenance procedures for tasks within subassemblies, and intends that these tasks be performed without controlling hazardous energies at the entire equipment level, the installation and maintenance manuals should provide appropriate energy isolation procedures at the subassembly level.

17.3 Electrical Energy Isolation

17.3.1 The main energy isolation capabilities (equipment supply disconnect) should be in a location that is readily accessible and should be lockable only in the de-energized position.

96: For equipment with multiple incoming supply sources, it is recommended that all of the energy isolation devices be located in one area.

17.4 Nonelectrical Energy Isolation

17.4.1 The equipment should include provisions and procedures so that hazardous energy sources, such as pressurized systems and stored energy, can be isolated or reduced to a zero energy state prior to maintenance or service work.

17.4.2 The hazardous energy isolation devices should be in a location that is readily accessible.

17.4.3 The hazardous energy isolation devices should be capable of being locked in the position in which the hazardous energy is isolated.

18 Mechanical Design18.1 This section covers hazards due to the mechanical aspects of the equipment.

97: This is similar to the essential requirements of European Union directives. The supplier has the option of demonstrating compliance by choosing standards that are appropriate to the machine and application.

98: Pressurized vessels must meet applicable codes and regulations.

18.2 All exposed surfaces that personnel are reasonably foreseen to contact should be free of sharp edges and burrs.

18.3 Machine Stability — Equipment, components, and fittings should be designed and constructed so that they are stable under reasonably foreseeable shipping, installation, and operating conditions. The need for special handling devices and anchors should be indicated in the instructions. Unanchored equipment in its installed condition should not overbalance when tilted in any direction to an angle of 10° from its normal position.

99: See IEC 61010-1 for an example of stability tests.

31 SEMI S2-0818E © SEMI 1991, 2018

18.4 Break-Up During Operation — The various parts of the equipment and its linkages should be able to withstand the stresses to which they are subjected when used as designed. Precautions should be taken to control risks from falling or flying objects.

18.4.1 The potential effects of fatigue, aging, corrosion, and abrasion for the intended operating environment should be considered as part of the mechanical hazards risk assessment.

18.4.2 Where a risk of rupture or disintegration remains despite the measures taken (e.g., a substrate chuck that loses its vacuum), the moving parts should be mounted and positioned in such a way that, in case of rupture, their fragments will be contained.

18.4.3 Both rigid and flexible pipes carrying liquids or gases should be able to withstand the foreseen internal and external stresses and should be firmly attached or protected against external stresses and strains. Based on the application, an appropriate factor of safety should be included.

18.5 Moving Parts — The moving parts of equipment should be designed, built, and positioned to avoid hazards. Where hazards persist, equipment should be fitted with guards or protective devices that reduce the likelihood of contact that could lead to injury.

18.5.1 Where the machine is designed to perform operations under different conditions of use (e.g., different speeds or energy supplies), it should be designed and constructed in such a way that selection and adjustment of these conditions can be performed safely.

18.5.2 Selection of Protection Against Hazards Related to Moving Parts — Guards or protective devices used to protect against hazards related to moving parts should be selected on the basis of a risk assessment that includes the:

hazards that are being guarded against;

probability of occurrence and severity of injury of each hazard scenario; and

frequency of removal of guards.

18.5.3 Guards and protection devices. Guards should:

reduce the risk that personnel will contact the mechanical hazard to an acceptable level; and

not give rise to additional risk.

18.6 Lifting Equipment — Lifting equipment used for maintenance and service of semiconductor manufacturing equipment (SME) should conform to each applicable criterion of ¶ 18.6 and its subordinate paragraphs.

100: The purpose of this section is to encourage that the hazards and potential consequences related to lifting operations (e.g., falling loads, collisions, tipping) be given appropriate consideration during design and development of SME.

EXCEPTION: Lifting equipment that has documentation indicating conformance with an applicable standard, code, or regulation need conform to only ¶ 18.6.3 , ¶ 18.6.4 , and their subordinate paragraphs, in addition to the applicable standard, code, or regulation.

18.6.1 Lifting Equipment Design Criteria

18.6.1.1 Mechanical Strength — Lifting equipment should be designed such that it has as a minimum factor of safety of 3, with the factor of safety determined as the ratio of yield strength to stress on each component, in the least favorable condition. For the purposes of § 18.6 , ‘least favorable condition’ is the position and orientation of fixed or moveable elements that places the greatest stress on the components of the lifting equipment. It may be necessary to test more than one condition so that each element is tested in its ‘least favorable’ condition. These elements include:

fixed or removable booms,

end effectors or grippers used in conjunction with fixed or removable booms, and

fixtures designed to provide interconnection between the load and the lifting device, excluding slings.

SEMI S2-0818E © SEMI 1991, 2018 32

101: A minimum factor of safety of 3 appears in several standards (e.g., ASME® 25 B30.20 Below-the-hook Lifting Device subparagraph 20-1.2.2 General Construction26).

102: Other factors of safety are required by codes, laws, and regulations, as they pertain to other types of lifting equipment, these must be met as well (e.g., EN 1492 requires a safety factor (SF) of 7 for webbing slings, MIL-STD-1365 B requires a SF of 5 for hoist rings, and ASME B18.15M requires a SF of 5 for lifting eyes). Conformance with these criteria for things other than the lifting device is typically evaluated separately from lifting equipment used in support of SME.

18.6.1.2 Materials should be appropriate for their intended use. Materials should be chosen with particular consideration to the effects of corrosion, abrasion, impact, and ageing.

18.6.2 Design Verification — The conformance to these criteria should be demonstrated for the particular lifting equipment under consideration, or a representative sample thereof.

18.6.2.1 Lifting equipment should undergo testing and verification that includes the following:

Classical engineering calculations;

Risk Assessment, such as Failure Modes and Effects Analysis (FMEA), and

Physical Testing, as described below for subsequently produced lifting equipment.

18.6.2.2 A written report, including photographs or drawings of how the testing was conducted along with written test specifications and results of all tests should be prepared.

18.6.2.3 Documentation, including the elements in ¶¶ 18.6.1 through 18.6.2.2 , and ¶ 9.6.3 (user documentation) should be prepared and kept for a sufficient time period to support the equipment while in service and for a sufficient period of time (typically a minimum of ten years) after the equipment is placed on the market. Conformance with this criterion may be demonstrated by making the documentation from design verification available to the assessor and providing the assessor evidence that the equipment supplier has a program that will retain the records for an appropriate period.

103: Several standards and directives (e.g., ISO 2415 (forged shackles), and 98/37/EC (Machinery Directive)) require keeping records for 10 years or more beyond the time the last unit was produced, tested and shipped.

18.6.3 Subsequently Produced Lifting Equipment — Each individual piece of lifting equipment should have testing and record keeping specifications in accordance with the criteria for static and dynamic load testing. Test certificates should accompany each unit upon delivery. The supplier should retain a copy of test records for at least 10 years from the date of shipment.

EXCEPTION: Lifting accessories permanently affixed to and tested as a part of a lifting fixture do not need individual testing.

18.6.3.1 Static Load Testing

18.6.3.1.1 Static load testing should be conducted on each lifting device at 150% of the rated load and with the mechanical elements of the structure in their least favorable conditions (see ¶ 18.6.1.1 for guidance as to determining the ‘least favorable condition’).

104: Static load test (proof load testing) of a new design is part of the process of validating the design’s maximum working load.

18.6.3.1.2 The static test should be conducted for a minimum of 2 minutes beyond the time that the test load has stabilized (stopped moving).

18.6.3.1.3 A static test should be considered acceptable if no permanent deformation or other physical damage is found once the test load has been removed and equipment examined. A static test resulting in damage or abnormality should be considered to be a failed test.

18.6.3.2 Dynamic Load Testing

18.6.3.2.1 Dynamic load testing should be performed on each lifting device, as this term is defined within this Document.

25 ASME trademark is owned by The American Society of Mechanical Engineers.26 American Society of Mechanical Engineers, Three Park Avenue, New York, NY 10016-5990, USA; Telephone: +1.973.882.1170, Fax: +1.973.882.1717, https://www.asme.org

33 SEMI S2-0818E © SEMI 1991, 2018

105: Dynamic load testing is conducted to confirm that the lifting equipment has been properly assembled, operated with account taken of the dynamic behavior of the lifting equipment and that all operational features, including mechanical stops, limit switches, brakes (if fitted) and all safety related features are fully adjusted and operational.

18.6.3.2.2 Dynamic load testing should be performed on lifting fixtures or lifting accessories, only if the number of load cycles to which they are foreseen to be subjected is sufficient to make such testing appropriate.

106: The American Welding Society® 27 (AWS® 28) Standard D14.1 Table 3 considers cyclic loading of 20,000 cycles and below to be equivalent to static loading. Thus, there is no need to consider dynamic testing of welded metal lifting fixtures or lifting accessories if the foreseen number of cycles in the fixture’s or accessory’s life is less than 20,000.

18.6.3.2.3 Dynamic load testing should be conducted;

using 110% of the working (rated) load,

and with the mechanical elements of the structure in their least favorable conditions,

for a minimum of two complete cycles at maximum operational speed of each axis of motion, and

if the control circuit allows for a number of simultaneous movements (e.g., rotation and displacement of the load), by combining the movements concerned.

107: For manual actuation of lifting equipment using a crank, it is recommended that the cranking speed be agreed upon by the supplier and evaluator based on the lifting device and the cranking mechanism. Manual cranks are not normally designed to a maximum cranking speed. The intent of this test is to verify that the cranking force is not sufficient to damage the lifting device when the device is exercised throughout its full operational range of motion. It is recommended that an agreed typical person be used to perform the cranking for this evaluation.

18.6.3.2.4 Acceptance Criteria

18.6.3.2.4.1 There should be no noticeable signs of improper assembly.

18.6.3.2.4.2 There should be no noticeable signs of excessive wear.

18.6.3.2.4.3 There should be no noticeable signs improper operation or incorrect adjustment of operational features, including mechanical stops, limit switches, and brakes (if fitted).

18.6.3.2.4.4 There should be no noises that indicate a problem other than that a simple adjustment is required.

18.6.3.2.4.5 All safety features should be operational and perform their intended function.

18.6.3.2.4.6 There should be no permanent set (yielding) of any mechanical or structural member.

18.6.4 Marking Criteria

18.6.4.1 Lifting equipment should be clearly marked in a lasting, and legible manner on a portion of the equipment that cannot be removed.

EXCEPTION: Lifting accessories permanently affixed to and tested as a part of a lifting fixture do not need individual marking.

108: Components of fixtures (e.g., individual components that make-up a larger lifting fixture) that could be used independently of their parent fixtures should be marked.

18.6.4.1.1 There should not be conflicting marks on any piece of lifting equipment. The working (rated) load should be visible and readable from the floor or working position.

18.6.4.1.2 The following minimum information should be included;

name and address of the manufacturer, or registered trade mark,

working (rated) load,

date of construction and initial testing of that unit, and

serial number, if any.

27 American Welding Society trademark is owned by American Welding Society.28 AWS trademark is owned by American Welding Society.

SEMI S2-0818E © SEMI 1991, 2018 34

109: There are additional marking requirements, imposed by various standards and regulations, depending on equipment type (e.g., hoist, slings, and accessories). The supplier must ensure that such additional information be considered and provided as required. This includes any markings required by directives or regional requirements (e.g., the CE mark for the EU).

18.6.5 Ergonomic Considerations

18.6.5.1 Lifting equipment is subject to the ergonomic design and assessment criteria, described elsewhere in this Safety Guideline, that are applicable to the SME. Therefore, ergonomic factors should be considered in the design of lifting equipment.

18.6.5.2 Handles or coupling points should be provided for use on lifting equipment that are to be positioned manually. Handles or coupling points should be positioned such that their use does not promote awkward postures. Postures and space requirements during movement of the lifting equipment should be evaluated as part of the overall ergonomic evaluation of the SME.

18.6.5.3 It is recommended that handles or coupling points be provided or identified for manually driven axes in an effort to discourage the user from grabbing the load itself or the hoisting rope to maneuver the load in the horizontal plane. However, there are conditions where the controlling of a load in order to place the load into a specific location or orientation will require the user to grab the load itself and provide guidance. This is acceptable, but it is recommended that moving a load, more than 5 cm (2 in.), be done using handles or specific coupling points identified on the lifting device for that purpose.

18.7 Mechanisms Supporting and Moving Hinged Loads

18.7.1 Applicability of § 18.7

18.7.1.1 Hinges and mechanisms that are constructed as part of the SME and are intended to support and lift nothing other than their associated hinged loads should conform to each applicable criterion of § 18.7 .

EXCEPTION: Hinged loads having a total mass not more than 5 kg (11 lb.).

18.7.1.2 Other lifting equipment used for maintenance and service of SME and used to lift hinged loads should conform to each applicable criterion of § 18.6 .

18.7.2 There are multiple ways by which the energy for movement of a hinged load can be provided:

18.7.2.1 Direct Human Power — Energy for lifting is supplied by a human and at a rate no greater than that at which it is provided by the human. This type includes simple machines (e.g., a handle mounted opposite a hinge) and complex machines (e.g., a winch driven by a human turning a crank handle which drives, through a series of gears, a drum which retracts a cable which, through a series of pulleys, lifts a load).

18.7.2.2 Stored Energy — At least some of the energy for lifting is supplied from a part of the mechanism in which it was stored, such as a spring (including a ‘gas spring’) or a counterweight.

18.7.2.3 External Power — Energy for lifting is supplied by an external source, such as an electric motor or pneumatic drive cylinder.

18.7.2.4 Combination of direct human power and stored energy.

18.7.2.5 Combination of external power and stored energy.

18.7.3 Design Criteria for Mechanisms Supporting and Moving Hinged Loads

18.7.3.1 Mechanical Strength — Mechanisms supporting hinged loads (including hinges) should be designed such that they have a minimum factor of safety of 3, where the factor of safety is the ratio of yield strength to stress on each component, in the least favorable condition. For the purposes of § 18.7 , ‘least favorable condition’ is the position and orientation of fixed or moveable elements that places the greatest stress on the components of the support mechanism.

110: Mechanisms supporting hinged loads include hinges; support hardware such as springs, gas-filled shocks, and spring dampeners; mounting hardware; and counterbalance mechanisms. This does not mean for example, a gas-filled shock must be ‘sized’ to hold 3 times the mass of the hinged component if it is used only as an ergonomic assist.

111: The ‘least favorable condition’ may differ from component to component. Therefore, more than one position may need to be considered in designing and testing to meet this criterion.

35 SEMI S2-0818E © SEMI 1991, 2018

112: Failure to follow procedural controls (e.g., not venting chamber or removing hardware) may have a significant effect on these structures. It is recommended that such conditions be fully explored using analysis methods listed in ¶  18.7.4.2 or other similar methods designed to identify critical deficiencies within a design or process.

18.7.3.2 Materials should be appropriate for their intended uses. Materials should be chosen with particular consideration to the effects of corrosion, abrasion, impact, and aging.

18.7.4 Design Verification — The conformance to these criteria should be demonstrated for each mechanism supporting a hinged load, or a representative sample of each such design.

18.7.4.1 Ergonomic Considerations — Means of moving hinged loads that use ‘direct human power’ (with or without ‘stored energy’) should be assessed to the applicable sections of Appendix APPENDIX 1 (SESC) of SEMI S8.

18.7.4.2 Mechanisms supporting and moving hinged loads should undergo verification and testing that includes:

classical engineering calculations;

risk assessment, such as failure modes and effects analysis (FMEA), and

physical testing under static and dynamic load.

113: ‘Classical engineering calculations’ are calculations based on: dimensions and masses of the components of the mechanism, dimensions and mass of the load, and typical characteristics of the materials of which they are constructed.

114: Several standards and directives (e.g., ISO 2415 (forged shackles) and 98/37/EC [Machinery Directive]) require keeping records for 10 years or more beyond the time the last unit was produced, tested and shipped.

18.7.4.3 Static Load Testing

18.7.4.3.1 Static load testing should be conducted on mechanisms supporting and moving hinged loads at 150% of the manufacturer’s intended configured load and with the mechanical elements of the structure in their least favorable conditions. This may be done prior to full integration, such as by using a test fixture, or after full integration.

115: The term ‘full integration’ refers to the level of assembly where the moveable part of the hinge is attached to its static hinge portion as required to complete the SME assembly.

18.7.4.3.2 See ¶ 18.7.3.1 for guidance as to determining the ‘least favorable condition.’

18.7.4.3.3 The static test should be conducted for a minimum of 2 minutes beyond the time that the test load has stabilized (stopped moving).

18.7.4.3.4 A static test should be considered acceptable if no permanent deformation or other physical damage is found once the test load has been removed and equipment examined. A static test resulting in damage or abnormality should be considered to be a failed test.

116: Static load test (proof load testing) of a new design is part of the process of validating the design’s maximum working load.

18.7.4.4 Dynamic Load Testing

18.7.4.4.1 Dynamic load testing should be conducted on hinged loads at 100% of the manufacturer’s intended configured load.

117: Dynamic load testing is conducted to confirm that equipment has been properly assembled and that all operational features, including mechanical stops, limit switches, brakes (if fitted) and all safety related features are fully adjusted and operational.

18.7.4.4.2 Dynamic load testing should be conducted for a minimum of five complete cycles at maximum operational speed of each axis of motion.

118: Dynamic testing of a hinged load at 100% of the manufacturer’s intended configured load is a different test than that specified in § 18.6 for lifting equipment. The latter has a more severe load condition than that stated for hinged loads and as such, may likely highlight areas of concern within two cycles of operation. For testing of hinged loads, it was felt that additional operational cycles should be performed, allowing more opportunity for the mechanism to be exercised and areas of concern amply reviewed.

18.7.4.4.3 Dynamic testing using human power should be performed at speeds that do not put the human at unacceptable risk.

SEMI S2-0818E © SEMI 1991, 2018 36

18.7.4.4.4 Acceptance Criteria

18.7.4.4.4.1 There should be no noticeable signs of improper assembly.

18.7.4.4.4.2 There should be no noticeable signs of excessive wear.

18.7.4.4.4.3 There should be no noticeable signs of improper operation or incorrect adjustment of operational features, including mechanical stops, limit switches, and brakes (if fitted).

18.7.4.4.4.4 There should be no noises that indicate a problem other than that a simple adjustment is required.

18.7.4.4.4.5 All safety features should be operational and perform their intended function.

18.7.4.4.4.6 There should be no permanent set (yielding) of any mechanical or structural member.

18.7.4.5 Documentation of Testing

18.7.4.5.1 A written report should be prepared and should include:

written test specifications,

photographs or drawings of how the testing was conducted, and

results of all tests.

18.7.4.5.2 Documentation, including the elements in §§ 18.7.3 through 18.7.4.5.1 , and § 9.6.3 (user documentation), should be prepared and kept for sufficient time to support the equipment while in service and for sufficient time (typically a minimum of ten years) after the equipment is placed on the market. Conformance with this criterion may be demonstrated by making the documentation from design verification available to the assessor and providing the assessor evidence that the equipment supplier has a program that will retain the records for an appropriate period.

18.7.5 Subsequently Produced Lifting Equipment — Each hinged load assembly supporting and moving a hinged load should be tested in accordance with § 18.7.4.4 and have records kept in accordance with § 18.7.4.5 . Test certificates should accompany each unit upon delivery. The supplier should retain a copy of test records for at least 10 years from the date of shipment.

18.8 Provisions for Work at Elevated Locations

119: The performance goal of § 18.8 and Related Information RELATED INFORMATION 18 is to ensure risks associated with performing work at elevated locations are either Low or Very Low, as assessed in accordance with SEMI S10.

18.8.1 Where operation, service or maintenance is required at elevated locations, a task analysis should be performed with risk assessment of the means of gaining access and of the performance of the work from the intended walking or working surface.

18.8.2 If the risk assessment determines a risk greater than Low, as assessed in accordance with SEMI S10, then an appropriate means of fall protection to mitigate the risk to Low or Very Low should be provided or specified.

18.8.3 Fall protection, including walking or working surfaces, and means of gaining access, such as ladders, stair ladders, platform stands, platforms, stairs, guardrail systems and handrails that are provided as standalone pieces or integral to the equipment should be designed in accordance with good engineering practices.

120: Examples of good engineering practices can be found in Related Information RELATED INFORMATION 18, as well as in various international standards. Good engineering practices also include consideration of intended use (e.g., energized electrical work).

121: There are many regional and international codes, as well as various international standards, and regulations with different requirements for the devices covered in Related Information RELATED INFORMATION 18. The selection of criteria for incorporation into Related Information RELATED INFORMATION 18 was based on meeting the majority of the different requirements, using the most conservative of the different requirements or using the most appropriate of the different requirements for the semiconductor industry.

18.8.4 Documents provided to the equipment user should include information (including, at a minimum, height of tasks, number of people required, and rated load) about the means of access that are to be used to perform tasks described in the supplier’s instructions but that are not provided by the supplier.

37 SEMI S2-0818E © SEMI 1991, 2018

18.8.5 Fall Protection

18.8.5.1 If fall protection is needed to mitigate the risk of work required at elevated locations, as assessed in accordance with SEMI S10, to Low or Very Low, fall protection should be specified or provided.

18.8.5.2 Fall protection may be accomplished with guardrail systems, fall arrest systems, fall restraint systems, or other equally effective means (see the definition of fall protection in ¶ 5.2.20 ).

122: Local or regional requirements may differ as to the height at which guarding is required to be provided.

California Code of Regulations, Title 8, Section 3210(b) calls for guarding to be used at heights of 1.2 m (4 ft.) or greater.

29CFR 1910.23(c)(1) requires “every open-sided floor or platform 4 feet or more above adjacent floor or ground level shall be guarded by a standard railing.”

ISO 14122-3, section 7.1.2 calls for guarding if there is a fall hazard above 500 mm (19.7 in.).

IBC® 29 2009, section 1013.1 calls for guarding to be employed at heights of 762 mm (30 in.) or greater.

18.8.5.3 If fall arrest or fall restraint systems are recommended by the equipment supplier, anchor points should be provided as part of the equipment or specified as part of the facility. Each anchor point should be designed or specified to support a static load of at least 22.24 kN (5,000 lbf.).

EXCEPTION: Fall arrest or fall restraint systems that meet the criteria for ‘certified’ (those designed and evaluated by a qualified person) may use two (2) times the arresting force or a static load of at least 8 kN (1,800 lbf.).

18.9 Extreme Temperatures — Surfaces that are accessible to personnel, and that are at high (per temperature limits in Table 1) or very cold temperatures (below −10°C [14°F]), should be fitted with guards or designed out.

18.9.1 Where it is not feasible to protect or design out the exposures to extreme temperature, temperatures exceeding the limits are permitted, provided that either of the following conditions is met:

unintentional contact with such a surface is unlikely; or

the part has a warning indicating that the surface is at a hazardous temperature.

Table 1 Potentially Hazardous Surface Temperatures

Accessible Parts

Maximum Surface Temperature, in °C

Metal Glass, Porcelain, Vitreous Material

Plastic,Rubber

Handles, knobs, grips, etc., held or touched for short periods (5 seconds or less) in normal use.

60 70 85

Handles, knobs, grips, etc. held continuously in normal use. 51 56 60External surfaces of equipment, or parts inside the equipment, that may be touched.

65 80 95

19 Seismic Protection123: Users have facilities located in areas that are susceptible to seismic activity. The specific forces experienced by a piece of equipment during a seismic event will depend largely on building design, installation details, and specific local ground conditions.

124: Preventing all damage to equipment during a particular seismic event is generally considered impractical. Nonetheless, it is useful if the design of the equipment limits the failure of parts that might result in unacceptable risk to personnel and the environment. These criteria are intended to accomplish two things:

1. Guide equipment suppliers to identify and correctly design the internal frame and components critical to controlling risk if the equipment is subject to anticipated seismic forces; and

2. Identify the equipment information needed by users to appropriately secure the equipment within their facility.

29 IBC trademark is owned by International Code Council, Inc.

SEMI S2-0818E © SEMI 1991, 2018 38

125: The user might require more stringent design criteria than what are given here because of increased site vulnerability (e.g., local soil conditions and building design may produce significantly higher accelerations), alternate installation scenarios, or local regulatory requirements.

19.1 General — The equipment should be designed so that if it is anchored as specified in the documentation provided to the equipment user, and it experiences anticipated seismic forces, it will not overturn, and no parts will fail or yield such that there would be a risk of injury to personnel, or adverse environmental impact of Medium or higher per SEMI S10.

126: § 19.2 contains criteria for anticipated seismic forces.

19.1.1 The determination of such parts should include consideration of potential equipment movement and overturning, leakage of chemicals (including fluid lines breaking and liquids splashing), failure of fragile parts (e.g., quartzware, ceramics) or cantilevered parts, hazardous materials release, fire, and projectiles.

19.1.1.1 Such parts should be accessible for visual evaluation of damage.

127: SEMI S8 contains guidelines for maintainability and serviceability; these may be used to estimate sufficient accessibility.

19.1.2 Structurally independent modules are modules which react to seismic forces independently and do not transfer the forces to adjacent modules. They should be assessed independently.

EXCEPTION: When any force that can be transferred to adjacent modules is a negligible level in comparison to the anticipated seismic force, those adjacent modules may be considered structurally independent.

19.1.3 Structurally dependent modules are modules which transfer the forces to each other. They should be assessed together.

128: Because the modules of cluster tools tend to have a complicated support structure, it is recommended that they be assessed for seismic protection and anchoring measures by qualified engineers.

129: SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by: education in mechanical, structural, civil, seismic, or architectural engineering; being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or experience in design, construction, and analysis of such structures.

19.1.4 The equipment should be considered in the condition it is anticipated to be in during normal operation and with all facilities operating normally, when and after the seismic forces are experienced.

19.1.5 The equipment supplier should indicate in the documents provided to the equipment user which utilities are necessary to limit risk to the level stated in ¶ 19.1 .

19.1.6 The seismic forces should be considered acting on the equipment’s center of gravity.

19.2 Anticipated Seismic Forces — The seismic forces anticipated to be experienced by the equipment (see ¶ 19.1 ) should be at least the following:

19.2.1 For equipment containing hazardous production materials (HPMs), a horizontal force equal to 94% of the weight of the equipment.

19.2.2 For equipment not containing HPMs, a horizontal force equal to 63% of the weight of the equipment.

19.2.3 Horizontal forces should be calculated independently on each of the X and Y axes, or on the axis that produces the largest forces on the anchorage points.

19.2.4 When calculating for overturning, a maximum value of 67% of the weight of the equipment for equipment containing HPMs and 74% of the weight of the equipment for equipment not containing HPMs should be used to resist the overturning moment.

130: See Related Information RELATED INFORMATION 4 for a discussion of how the values were selected. The lighter effective weight is the worst case when calculating the overturning moment.

131: Because equipment may be placed into service anywhere in the world, it is recommended that the seismic protection design of the equipment be based upon requirements that allow the equipment, as designed, to be installed in most sites worldwide. It is recommended that interested parties consult a qualified mechanical, civil, or structural engineer to determine building code requirements for a particular location. Related Information 4 contains examples of seismic force criteria in various world regions.

39 SEMI S2-0818E © SEMI 1991, 2018

132: The above minimum anticipated seismic forces are based on requirements for rigid manufacturing or process equipment constructed of high-deformability materials and installed mid height in the fab, and are intended to be sufficient for the basic safety goals of SEMI S2.

19.3 The supplier should provide the following data and procedures to the user. This information should be included in the installation instructions as part of the documentation covered in § 9 .

A drawing of the equipment, its support equipment, its connections (e.g., ventilation, water, vacuum, gases) and the anchorage locations identified in § 19.4 .

The type of feet used and their location on a base frame plan drawing.

The weight distribution on each foot.

Physical dimensions, including width, length, and height of each structurally independent module.

Weight and location of the center of mass for each structurally independent module.

Acceptable locations on the equipment frame for anchorage.

19.4 The locations of the tie-ins, attachments, or anchorage points intended by the supplier to limit equipment motion during a seismic event should be clearly identified by permanently affixed marks or labels (e.g., symbols or text) unique to this purpose on the equipment and a related explanation in the equipment installation documentation provided to the equipment user.

133: It is not the intent of SEMI S2 that the supplier provide the seismic attachment point hardware. Such hardware may be provided as agreed upon between supplier and user.

134: It is the responsibility of the user to verify that the vibration isolation, leveling, seismic reinforcing, and load distribution is adequate.

20 Automated Material Handlers20.1 This section covers automated material handlers, which include:

substrate handlers;

industrial robots and industrial robot systems; and

unmanned transport vehicles (UTVs).

135: Substrate handlers typically handle a single substrate at a time, and are distinguished from industrial robots by their small load capacity.

20.2 General — The means of incorporating personnel safeguarding into automated material handlers should be based on a hazard analysis. The hazard analysis should include consideration of the size, capacity, speed, and spatial operating range of the handler.

20.2.1 Subsystem Stops — If a separate stop button is used for the automated material handler, it should be differentiated from the EMO button.

20.3 Substrate Handlers — See § 20.2 , General.

20.4 Industrial Robots and Industrial Robot Systems — Industrial robots and industrial robot systems should meet the requirements of appropriate national or international standards (e.g., ANSI/RIA R15.06, ISO 10218-1, CEN EN 775). If there are deviations from these standards because of semiconductor applications of the robot, these deviations may be found acceptable based on risk assessments.

20.5 UTVs

136: There are two basic types of UTVs: (1) the floor-traveling (including both rail-guided and rail-independent) UTV, that automatically travels on the floor to a specified destination where it is unloaded or loaded; and (2) the space-traveling UTV, which automatically travels without resting on the floor (e.g., in the space below the ceiling) to a specified destination where it is loaded or unloaded. UTVs do not include rail-guided mechanisms that are attached to equipment (such as in wet benches).

20.5.1 Collision Avoidance — UTVs generally travel in wide areas and are used in a system rather than stand-alone operation. UTVs should be equipped with a noncontact approach sensing device so that they do not inadvertently contact people or other objects.

SEMI S2-0818E © SEMI 1991, 2018 40

20.5.2 UTVs — Loading and Unloading Equipment

20.5.2.1 UTVs should be interlocked with equipment such as semiconductor process equipment, automated load ports, stockers, ground-based conveyors, and automated warehouses as needed to ensure that the load remains secure and that the UTV and transfer components are not in conflict with one another.

20.5.2.2 If loading results in an unsafe condition, the equipment should detect and indicate the condition, and movement of all loading equipment should stop immediately. The system should not reset or restart automatically.

21 Environmental Considerations21.1 This section covers environmental impacts throughout the life of the equipment.

137: It is recommended that environmental impacts be balanced against other factors, including safety and health, legal, and regulatory requirements.

138: It is recommended that the manufacturer maintain awareness of relevant environmental regulations, either internally or through the user.

139: The user is responsible for providing the manufacturer with information regarding any environmental restrictions that are specific to a given site and that may impact equipment design (e.g., cumulative emissions limits, permit requirements, site-specific programs).

140: See § 14 for fire suppression emission issues.

141: References to ‘process’ in this section are meant to refer to the baseline process.

21.2 Design

21.2.1 The following design guidelines apply to all phases of equipment life, from concept to decommissioning and disposal.

142: The documentation described in §§ 8.5.3 and 9.4 provide information that can be used for evaluating conformance to this section.

21.2.2 Resource Conservation

21.2.2.1 The manufacturer should consider resource conservation (i.e., reduction, reuse, recycling) during equipment design, for example:

water reuse or water recycling within the equipment;

reduced chemical consumption, energy use, and water use (e.g., reducing resource use when no process is occurring);

reduced use of resources during maintenance procedures (e.g., parts cleaning procedures could include minimum rinse rates and rinse times);

recycling or reusing chemicals in the equipment, rather than consuming only new materials;

reducing volume of packaging, increasing recycled content of packaging, and/or designing reusable packaging.

21.2.3 Chemical Selection

21.2.3.1 Chemical selection for process, maintenance, and utility uses (e.g., gases, etchants, strippers, cleaners, lubricants, and coolants) should take into account effectiveness, environmental impacts, volume, toxicity, by-products, decommissioning, disposal, and recyclability; use of the least hazardous chemical is preferred . To the extent practicable, the utilities, maintenance, and process should be designed so that the equipment operates without the use of:

ozone depleting substances (ODSs) as identified by the Montreal Protocol, such as chlorofluorocarbons (CFCs), methylchloroform, hydrochlorofluoro-carbons (HCFCs), and carbon tetrachloride, or

perfluorocompounds (PFCs), including CF4, C2F6, NF3, C3F8, and SF6, and CHF3 due to their global warming potential.

21.2.4 Prevention and Control of Unintended Releases

41 SEMI S2-0818E © SEMI 1991, 2018

21.2.4.1 Equipment design, including feed, storage, and waste collection systems, should prevent potential unintended releases. At a minimum:

21.2.4.2 Secondary containment for liquids should be capable of holding at least 110% (see first row of Table AA1-1.3.1.1 Table A1-1 of Appendix APPENDIX 1) of the volume of the single largest container, or the largest expected volume for any single point failure.

143: In some circumstances secondary containment may be specified by the equipment supplier, but provided by the user.

21.2.4.3 Chemical storage containers and secondary containment should be designed for accessibility and easy removal of collected material.

21.2.4.4 Secondary containment should have alarms and gas detection or liquid sensing, as appropriate, or have recommended sensing points identified in the equipment installation instructions.

21.2.4.5 Equipment design should allow personnel to determine all in-equipment container levels conveniently without having to open the containers, where ignorance of the level could result in an inadvertent release.

21.2.4.6 Overfill level detectors and alarms should be provided for in-equipment containers.

21.2.4.7 Secondary containment and other control systems should be designed to ensure that chemicals cannot be combined, where the combination could result in an inadvertent release.

21.2.4.8 Equipment components should be compatible with chemicals used in the manufacturing process. Chemical systems should be designed for the specified operating conditions, and have sufficient mechanical strength and corrosion resistance for the intended use.

21.2.4.9 Equipment should be able to accept a signal from a monitoring device and stop the supply of chemical, at the first nonmanual valve within the affected system.

21.2.4.10 Chemical distribution systems should be capable of automatic shutoff and remote shutdown.

21.2.5 Effluents, Wastes, and Emissions

144: It is recommended that the manufacturer document its efforts to minimize the equipment’s generation of hazardous wastes, solid wastes, wastewater, and air emissions.

145: It is recommended that SEMI F5 be used for guidance in gaseous effluent handling.

21.2.5.1 Equipment design that allows connection to a central waste collection system is preferred, except where collection at the equipment may facilitate recycling or reuse opportunities or otherwise reduce environmental impacts.

146: It is recommended that individual drains and exhausts be kept separate (e.g., separate outlets for acid drain, solvent drain, deionized (DI) water drain; acid exhaust, solvent exhaust).

21.2.5.1.1 Point-of-use collection containers should be designed for accessibility as well as the possible reuse and recycling of the collected materials.

21.2.5.2 Equipment should use partitions, double-contained lines, or other similar design features to prevent the mixing of incompatible waste streams.

21.2.5.3 The manufacturer should evaluate the feasibility of including integrated controls for effluent and emission treatment.

21.2.5.4 Dilution in excess of process or safety requirements should not be used to reduce contaminant discharge concentrations.

21.2.5.5 Segregation of effluents, wastes, and emissions should be provided in the following cases:

where chemically incompatible;

where segregation facilitates recycling or reuse; or

where separate abatement or treatment methods are required.

SEMI S2-0818E © SEMI 1991, 2018 42

147: It is recommended that the equipment design documentation show evidence of consideration of by-products generated during equipment operation, clean-up, maintenance, and repair. By-products can include deposits in drains or ducts, and replaceable parts (e.g., batteries, vapor lamps, contaminated parts).

21.2.6 Decommissioning and Disposal

21.2.6.1 Equipment design should address (see § 8.5.3 for documentation provisions) construction material and component reuse, refurbishment, and recycling.

21.2.6.2 The equipment should be designed to facilitate equipment decontamination and disposal (e.g., by use of removable liners or replaceable modules). This includes minimizing the number of parts that become contaminated with hazardous materials.

148: It is recommended that SEMI S12, Environmental, Health and Safety Guideline for Manufacturing Equipment Decontamination, be used for guidance during equipment decontamination.

22 Exhaust Ventilation22.1 Equipment exhaust ventilation should be designed to prevent potentially hazardous chemical exposures to employees as follows:

22.1.1 As primary control when normal operations present potentially hazardous chemical exposures to employees by diffusive emissions that cannot be otherwise prevented or controlled (e.g., wet decks, spin coaters).

149: In the context of this section, ‘primary control’ means that it is the control of first choice (e.g., rather than personal protective equipment).

22.1.2 As supplemental control when intermittent activities (e.g., chamber cleaning, implant source housing cleaning) present potentially hazardous chemical exposures to employees which cannot reasonably be controlled by other means. Supplemental exhaust hoods or enclosures may be integrated into the equipment design, or supplied completely by the equipment user.

22.1.2.1 When a procedure (e.g., cleaning) specified by the supplier requires exhaust ventilation, the supplier should include the minimum criteria for exhaust during the procedure.

22.1.3 As secondary control when a single-point failure presents the potential for employee exposures to hazardous materials, and this exposure cannot be controlled by other means (e.g., use of all welded fittings).

EXCEPTION: Secondary exhaust control enclosures for non-welded connections (e.g., valve manifold boxes that enclose piping jungles) are not included in this Safety Guideline for those hazardous gases that are transported below atmospheric pressure (e.g., via vacuum piping systems) if it can be demonstrated that equivalent leak protection is provided. Equivalent protection may include such things as equipping the vacuum delivery system with a fail-safe (e.g., to close) valve automatically activated by a loss of vacuum pressure. Loss of vacuum pressure should also activate a visual and audible alarm provided in visual or audible range of the operator.

22.2 Equipment exhaust ventilation should be designed and a ventilation assessment conducted in accordance with both § 23.5 and SEMI S6, to control, efficiently and safely, for potential worst-case, realistic employee exposures to chemicals during normal operation, maintenance, or failure of other equipment components (hardware or software). All design criteria and test protocols should be based on recognized methods. See also § 23.3 .

22.3 Documentation should be developed showing the equipment exhaust parameters and relevant test methods, and should include:

duct velocity (where needed to transport solid particles);

volumetric flow rate Q;

capture velocity (where airborne contaminants are generated outside an enclosure);

face velocity (where applicable);

hood static pressure SPh;

duct diameter at the point of connection to facilities; and

location(s) on the duct or hood where all ventilation measurements were taken.

43 SEMI S2-0818E © SEMI 1991, 2018

22.4 Exhaust flow interlocks should be provided by the manufacturer on all equipment that uses HPMs where loss of exhaust may create a hazard. Flow (e.g., pitot probe) or static pressure (e.g., manometer) switches are the preferred sensing methods.

150: Sail switches (switches that are connected to a lever that relies upon air velocity to activate) are generally not recommended.

151: It is recommended that the pressure or flow measuring point be located upstream of the first damper.

152: § 11 contains provisions for safety interlocks.

22.4.1 When the exhaust falls outside the prescribed limits (i.e., below the minimum or above the maximum specified by the equipment supplier), an alarm should be provided within audible or visible range of the operator, and the process equipment should be placed in a safe stand-by mode. A time delay for the equipment to go into standby mode may be allowable, based on an appropriate risk assessment. The system should be capable of interfacing with the facility alarm system.

153: If exhaust is being monitored by only a flow sensing device, abnormally high flow may well indicate an unacceptable condition. For example, if a door to an enclosure is open, the flow will be abnormally high, but the differential pressure will be abnormally low and the flow pattern will be substantially changed. If such conditions present an unacceptable risk, the equipment supplier needs to specify an upper set point for a flow monitor. However, if excess flow conditions are acceptable, the upper limit can be infinite, thereby making it impossible for the flow to exceed the upper set point and obviating the need for an alarm.

154: It is recommended that non-HPM chemical process exhaust be equipped with audible and visible indicators only.

22.4.2 Exhaust flow interlocks and alarms should require manual resetting.

22.4.3 Exhaust flow interlocks should be fault-tolerant.

22.5 Equipment and equipment components should be designed using good ventilation principles and practices to ensure chemical capture and to optimize exhaust efficiency.

155: It is recommended that exhaust optimization be achieved with total equipment static pressure requirements of −10 to −375 Pa (−1 to −38 mm H2O or −0.05 to −1.5 inches H2O). See also § 6.6 of SEMI S6-0707.

156: Related Information 16 contains recommendations on design.

23 Chemicals23.1 The manufacturer should generate a chemical inventory identifying the chemicals anticipated to be used or generated in the equipment. At a minimum, this should include chemicals in the recipe used for equipment qualification or ‘baseline’ recipe, as well as intended reaction products and anticipated by-products. Chemicals on this list that can be classified as HPMs, or odorous (odor threshold <1 ppm) or irritant chemicals (according to their material safety data sheets), should also be identified.

23.2 A hazard analysis (see § 6.8 ) should be used as an initial determination of chemical risk as well as to validate that the risk has been controlled to an appropriate level.

23.2.1 The hazard analysis, at a minimum, should address the following conditions:

potential mixing of incompatible chemicals;

potential displacement of oxygen;

potential chemical emissions during routine operation;

potential chemical emissions during maintenance activities; and

potential key failure points and trouble spots (e.g., fittings, pumps).

23.2.2 All routes of exposure (e.g., respiratory, dermal) should be considered in exposure assessment.

23.3 The order of preference for controls in reducing chemical-related risks is as follows:

23.3.1 Substitution or elimination (see also § 21.2.2 );

23.3.2 Engineering controls (e.g., enclosure, ventilation, interlocks);

23.3.3 Administrative controls (e.g., written warnings, standard operating procedures);

SEMI S2-0818E © SEMI 1991, 2018 44

23.3.4 Personal protective equipment.

23.4 The design of engineering controls (e.g., enclosure, ventilation, interlocks) should include consideration of (see also Appendix APPENDIX 1):

pressure requirements;

materials incompatibility;

equipment maintainability;

chemical containment; and

provisions for exhaust ventilation (see § 22 ).

23.5 During equipment development, the supplier should conduct an assessment that documents conformance to the following airborne chemical control criteria. All measurements should be made using a method in accordance with § 23.5.1 with documented sensitivities and accuracy. The sample location(s) and conditions should be representative of the reasonably foreseeable, worst-case, personnel breathing zone. A report documenting the survey methods, equipment operating parameters, instrumentation used, method detection limits, calibration data, results, why each industrial hygiene laboratory selected was appropriate and discussion should be provided as part of the SEMI S2 report.

23.5.1 Air Sampling Method Selection

23.5.1.1 When available for the substance of concern (SOC) (also known as ‘analyte’) and concentration being evaluated, one of the following methods should be used:

A sample collected by a time-integrated sampling means (e.g., diaphragm pump with a calibrated flowrate or passive monitor) collected and analyzed per a validated method.

Direct reading instrumentation (real-time) as used per the manufacturer’s specification and guidance.

Collection of an SOC (analyte) in a sample bag (e.g. Tedlar®® 30 air sample bag) or a calibrated (i.e., known sample collection rate) vacuum canister accepted by an industrial hygiene laboratory for analysis using a validated method.

157: The validated method in 1st bullet might contain pump calibration information.

158: Manufacturer’s specification and guidance in 2nd bullet usually include information on calibration, measurement techniques, interferences and analysis limitations.

159: SOCs collected in a vacuum canister or sample bag (3 rd bullet) must be stable (e.g., compatible with container, does not breakdown chemically) in order to be able to forward to an industrial hygiene laboratory without impact to the sample. Contact the industrial hygiene laboratory to determine if the SOC is sufficiently stable.

23.5.1.2 A surrogate material may be used if the SOC has hazardous properties or inadequate detection methods which make the SOC unsuitable for conducting testing in a safe or efficient manner. Use of a surrogate should be conducted in accordance with SEMI S6. If a surrogate is used then the result of the air sample testing should be compared to the SOC OEL/LFL (not the identified surrogate OEL/LFL). An explanation of why the surrogate is used and is still representative of the SOC should be included as part of the S2 report including consideration of the following:

Whether the material has an equal or greater vapor pressure or evaporation rate under stated process conditions for the SOC (e.g., temperature, pressure, relative humidity, air-flow, etc.);

Whether air sampling test conditions (as applicable for material properties and use application) are representative compared to the target SOC. The characteristics of the selected surrogate chemistry may result in a more conservative test or conditions compared to the target SOC.

Whether the sampling method lower detection limit for the surrogate ensures the ability to compare to the SOC OEL.

23.5.1.3 If no method is known that meets the criteria for testing in ¶¶ 23.5.1.1 or 23.5.1.2 , then select an available method with consideration of factors such as the lower detection limit accuracy and cross-sensitivity. An 30 Tedlar trademark is owned by E. I. Du Pont De Nemours And Company.

45 SEMI S2-0818E © SEMI 1991, 2018

explanation of why the method was selected should be included as part of the SEMI S2 report. This clause applies to the ability to measure adequate lower detection levels in order to determine conformance against the criteria detailed in ¶¶ 23.5.3 through 23.5.6 (e.g., 1% and 25% of the OEL).

23.5.1.4 Samples should be analyzed by an industrial hygiene laboratory as required.

23.5.2 Chemical emissions to the workplace environment during normal equipment operation should be at the lowest practical level. Conformance to this section can be shown by demonstrating ambient SOC air concentrations to be less than 1% of the applicable Occupational Exposure Limit(s) (OEL(s)) during normal equipment operation. Measurement locations should be representative of the reasonably foreseeable worst-case exposure in personnel breathing zones.

EXCEPTION: Sampling during normal operations for closed processing equipment (see SEMI S6 for the definition of closed process equipment), is not required.

160: Selection of the lowest applicable OEL based on the target SOC(s) and exposure duration, published by a professional or governmental agency and with consideration of the appropriate OEL category (e.g., time-weighted average [TWA], ceiling [C] and short-term exposure limits [STELs]) is the recommended approach in order to cover all installations and end-user locations. An alternate strategy to selecting the lowest applicable OEL is to select the applicable OEL that relates only to the regions or countries in which the equipment will be used. Two online resources that can help initially identify OELs around the world are:

OSHA annotated Permissible Exposure Limits (PEL) Tables (includes the ACGIH Threshold Limit Values -– TLV® 31s) which can be found at https://www.osha.gov/dsg/annotated-pels/

GESTIS International Limit Values database which can be found at http://limitvalue.ifa.dguv.de/Webform_gw2.aspx

23.5.3 Chemical emissions during maintenance activities should be at the lowest practical level. Conformance to this section can be shown by demonstrating ambient SOC air concentrations to be less than 25% of the applicable OEL(s), during maintenance activities. Measurement locations should be representative of the reasonably foreseeable worst-case exposure in personnel breathing zones.

23.5.4 Chemical emissions during equipment failures should be at the lowest practical level. Conformance to this section can be shown by demonstrating ambient SOC air concentrations to be less than 25% of the applicable OEL(s) during a realistic worst-case failure. Measurement locations should be representative of the reasonably foreseeable worst-case exposure in personnel breathing zones.

23.5.5 Emissions of flammable or combustible chemistries during normal equipment operations, maintenance activities and reasonably foreseeable, worst-case system failure conditions should be controlled to be less than 25% of the lower flammable limit (LFL) on the exterior of the equipment and at the worst case representative potential ignition sources internal to the equipment, as identified as part of a fire risk assessment.

EXCEPTION: Control of emissions does not prohibit the use of combustion modules (e.g., flammable effluent treatment equipment) that use burning a flammable mixture as part of the intended equipment design and normal operations.

[161:] Controlling flammable vapors to less than 25% of the applicable LFL at potential ignition sources is defined in international International fire Fire code Code® 32 (IFC® 33). Refer to SEMI S6 for additional information regarding requirements and tracer gas test methodology for flammable and combustible SOCs.

161:[162:] Assessment of ignition sources can include consideration of engineering controls such as supplying an inert atmosphere, use of intrinsically safe components or ignition source encapsulation when implemented in conformance with the appropriate standard.

23.5.6 The following information should be included in the supporting rationale for the findings related to the above paragraphs in § 23.5 .

SOC(s) considered for the evaluation,

Rationale for the sampling method used,

31 TLV trademark is owned by American Conference of Governmental Industrial Hygienists, Inc. 32 International Fire Code trademark is owned by International Code Council, Inc.33 IFC trademark is owned by International Code Council, Inc.

SEMI S2-0818E © SEMI 1991, 2018 46

The OEL, type of OEL (for example, Time Weighted Average (TWA), Short Term Exposure Limit (STEL), ceiling) and source of the OEL (for example, ACGIH, German MAK, US OSHA) used in the evaluation,

Whether the testing used the SOC or a surrogate, and

The level of detection achieved during testing.

23.6 Equipment that uses hazardous gases may require continuous detection and, if so, should have sample points mounted in the equipment, or have recommended sampling points identified in the equipment installation instructions. Where the gas supply is part of or controlled by the equipment, the equipment should be able to accept a signal from an external monitoring device and shut down the supply of the gas.

23.7 Appropriate hazard alert labels should be placed at all chemical enclosure access openings.

24 Ionizing Radiation24.1 This section covers equipment that produces ionizing radiation (e.g., X-rays, gamma rays) or uses radioactive sources.

24.2 Accessible emissions of ionizing radiation should be designed as low as reasonably achievable. This criteria can be met by demonstrating conformance to the provisions in §§ 24.2.1 , 24.2.2 , and Appendix APPENDIX 2.

24.2.1 Accessible levels of ionizing radiation during normal operations should be less than 2 microsieverts (0.2 millirem) per hour above background. See also Table AA2-1.3.1.1 Table A2-1 of Appendix APPENDIX 2.

24.2.2 Accessible levels of ionizing radiation during maintenance and service procedures should be less than 10 microsieverts (1 millirem) per hour above background. See also Table AA2-1.3.1.1 Table A2-1 of Appendix APPENDIX 2.

24.2.3 Access to radioactive contamination or internal exposure (e.g., inhalation, ingestion) to radioactive materials should be minimized. The hazards and controls for the prevention of personnel contamination and internal exposures should be detailed in the operation and maintenance manuals.

162:[163:] The use of radioactive material is strictly regulated around the world. Import, export, and transportation of radioactive materials is also highly regulated. Licenses may be required to possess, use, and distribute radioactive materials.

163:[164:] Many regions require both user and import licenses, and the timely acquisition of these licenses depends on the information provided by the equipment supplier.

164:[165:] Radiation producing machines are also regulated around the world. Regulations and licensing requirements may cover activities such as importing, exporting, installing, servicing and using radiation producing equipment.

24.2.4 The manufacturer should supply, in the user documentation, a contact phone number and address for the manufacturer’s radiation safety support personnel.

24.3 Equipment should be designed to minimize access or exposure to ionizing radiation during normal operation, maintenance, and service. Potential exposures should be controlled in the following order of preference:

24.3.1 Engineering Controls — Engineering controls (e.g., shielding, interlocks) should be the primary mechanism to minimize emission of ionizing radiation or access to ionizing radiation.

24.3.1.1 Radiation shielding for the equipment facilities connections (e.g., gas and exhaust lines) should be designed such that removal and replacement of the shielding during installation is minimized.

24.3.1.2 Non-defeatable safety interlocks should be provided on barriers preventing maintenance access to radiation fields in excess of 10 microsieverts (Sv) or 1 millirem per hour.

24.3.2 Administrative Controls — When administrative controls (e.g., distance, time, standard operating procedures, labeling) are to be used, the equipment supplier should provide detailed documentation explaining the use of the administrative controls.

24.4 Equipment utilizing or producing ionizing radiation should be labeled appropriately.

165:[166:] Label contents are typically controlled by regulation in the country in which the equipment is to be used.

24.5 The manufacturer should conduct an assessment to document conformance to the criteria specified in ¶¶ 24.2.1 through 24.2.2 during normal equipment operation, maintenance, and service.

47 SEMI S2-0818E © SEMI 1991, 2018

24.5.1 A radiation survey should be used to confirm design compliance and serve as a baseline survey. See also Table AA2-1.3.1.1 Table A2-1 of Appendix APPENDIX 2.

24.5.2 Measurements should be taken using recognized methods with documented sensitivities and accuracy. A report documenting the survey methods, equipment operating parameters, instrumentation used, calibration data, source locations, results, and discussion should be made available.

24.5.3 If supplemental administrative controls are recommended based on survey results or calculations, a discussion should be provided in the operations and maintenance manuals describing the source locations, radiation levels, and recommended control measures.

166:[167:] Ionizing radiation sources must be registered or licensed according to the regulations of the country of destination. These radiation sources must conform to the regulations of central or local government agencies, whichever is stricter.

167:[168:] It is recommended that equipment containing radioactive materials should demonstrate conformance to licensing with local regulatory agencies prior to shipment.

168:[169:] Equipment that uses particle acceleration in its process has the potential for generating ionizing radiation as a result of nuclear interactions between the accelerated particles and various materials. These materials can include materials of construction of the equipment, accumulated residual process materials in the equipment, and the target materials.

25 Non-Ionizing Radiation and Fields25.1 This section covers equipment that produces non-ionizing radiation, except laser sources, in the following categories:

static electric and magnetic (0 Hz),

sub-radio frequency electric and magnetic fields (<3 kHz),

radio frequency (3 kHz to 300 GHz), and

optical radiation (300 GHz to 1,670 THz) (wavelengths of 1 mm to 180 nm).

25.2 Hazardous non-ionizing radiation emissions that are accessible to any personnel should be limited to the lowest practical level. This criterion can be met by demonstrating that the accessible levels of non-ionizing radiation are below the exposure limits set in Appendix APPENDIX 3. Medical device labeling levels are addressed in § 25.5.

25.2.1 When a partial body (e.g., limb) exposure limit is used, the general limit should still be met at the expected location of the head and torso of the person while performing the task. If compliance with both exposure limits places restrictions on the body position for the task (e.g., the static magnetic object must be held a specified distance from the torso) then all of the following should be met:

the restrictions on body position should be clearly described in the manuals both in the general safety or hazard description section and in the specific task instructions, as appropriate (see § 25.6 ),

the restrictions on body position should be clearly indicated in the hazard alert labels (see § 25.5 ),

the restrictions on body position should be included in the ergonomic evaluation.

25.3 Sources of potentially hazardous non-ionizing radiation should be identified in the operation and maintenance manuals, and appropriate parameters listed. Parameters include frequency, wavelength, power levels, continuous wave or pulsed (see also Appendix APPENDIX 3). If pulsed, parameters also include the pulse repetition rate, pulse duration, and description of the pulse waveform.

EXCEPTION: Visible sources which are intended to be viewed or which provide illumination (e.g., display panels, visible alarm indicators), and are not lasers, do not need to be identified.

169:[170:] It is recommended that UV/IR generators that are part of fire protection test apparatus, and are provided with the equipment, be considered as possible sources of potentially hazardous non-ionizing radiation.

25.4 Equipment should be designed to minimize access or exposure to non-ionizing radiation during normal operation, maintenance, and service. Potential exposures should be controlled in the following order of preference:

25.4.1 engineering controls (e.g., enclosure, shielding, guarding, grounding, interlocks);

SEMI S2-0818E © SEMI 1991, 2018 48

25.4.2 administrative controls (e.g., written warnings, standard operating procedures, labeling); and

25.4.3 personal protective equipment.

25.5 Equipment utilizing or producing potentially hazardous non-ionizing radiation should be labeled.

25.5.1 Hazard alert labels should be provided by the manufacturer when emission levels are measured that may impact implanted or wearable medical devices (e.g., cardiac pacemakers or insulin pumps) or implanted ferromagnetic devices. These alert labels should be located where the emissions exceed the medical device labeling limit (see Appendix APPENDIX 3 for medical device labeling levels and references). While ‘implanted medical devices’ is the more generic and preferred term, ‘pacemaker’ is considered an equivalent term for use on the hazard alert labels.

25.5.2 Hazard alert labels should be provided by the manufacturer where static magnetic field levels are measured that may cause tools or parts to move or may dislocate magnetizable prostheses.

EXCEPTION: If the field is small enough that the field strength lines for affecting implanted medical devices and moving ferromagnetic parts are within 2 cm, then the implanted medical device label (see ¶ 25.5.1 ) is sufficient to meet this criterion.

25.6 The manufacturer should conduct an assessment to document conformance to the criteria specified in § 25.2 . Engineering calculations may be used as part of this assessment. All measurements should be taken using recognized methods with documented sensitivities and accuracy. A report documenting the survey methods, equipment operating parameters, instrumentation used, calibration data, source location(s), and discussion should be provided in the evaluation report (see Appendix APPENDIX 3).

25.6.1 If supplemental administrative controls are recommended based on survey results or calculations, a discussion should be provided in the operations and maintenance manuals describing the source location(s), radiation levels, and recommended control measures.

25.6.2 Administrative control procedures recommended for operation, maintenance, or service activities should be documented in the operations and maintenance manuals.

26 Lasers26.1 Equipment containing lasers should be properly identified with a laser product classification. This classification should be based on the laser radiation level accessible during operation, per the applicable standard or regulation. The laser product classification, applicable standard, and the certification file number (where appropriate) should be documented on a Laser Data Sheet (format in Part 1 of Appendix  APPENDIX 5) that is provided to the user.

26.1.1 As an alternative to completing a Laser Data Sheet, the equipment manufacturer may provide the information that is specified on the Laser Data Sheet in another format. The information should be organized so the user can easily read and understand it.

26.1.2 Equipment should not exceed the laser product classification of Class 2; however, individual lasers may exceed this classification prior to integration into the final equipment assembly.

26.1.3 Equipment and lasers should be labeled according to the appropriate standards (e.g., IEC 60825-1, 21 CFR 1040.10).

170:[171:] A Class 1 product label is required in some jurisdictions, but is not currently required in the United States.

171:[172:] The laser product classification for some equipment is Class 1 or 2, even though an embedded laser is of higher hazard classification.

26.1.4 Equipment suppliers should provide maintenance or service task information in the documents provided to users for equipment that requires access to laser radiation in excess of the maximum permissible exposure (MPE).

26.1.4.1 The information for these tasks should be documented on a Laser Data Sheet (see Appendix  APPENDIX5) in the documents provided to users and should include the accessible laser and beam parameters (see § AA5-2 ), laser control measures (see § AA5-3 ) and personal protective equipment (see § AA5-4 ) for each laser or task requiring this access.

49 SEMI S2-0818E © SEMI 1991, 2018

EXCEPTION 1: In the case of proprietary beam parameters, an acceptable alternative is to provide the nominal ocular hazard distance (NOHD) results (according to IEC 60825-1 or its equivalent) for each task requiring access above the MPE.

EXCEPTION 2: If a laser system is a stand-alone laser product delivered as a component or spare for laser equipment, the laser system supplier’s responsibility for Laser Data Sheet information is limited to that which applies specifically to the stand-alone laser product and not the integrated laser equipment.

26.1.5 The physical location of the embedded laser sources and access points within the laser product should be identified in the documents provided to users.

26.2 Equipment, including beam diagnostic or alignment tools, should be designed to prevent injury from all lasers during normal operation, and should minimize risk of injury during maintenance or service. Potential exposures should be controlled in the following order of preference:

26.2.1 Engineering controls (e.g., enclosures, shielding, filters, use of fiber optics to transmit energy, interlocks).

26.2.2 Temporary enclosures or control measures for maintenance, service, and non-routine tasks.

26.2.3 Administrative controls (e.g., written warnings, standard operating procedures, labeling).

26.2.4 Personal protective equipment.

172:[173:] Temporary enclosures and personal protective equipment are considered to be administrative controls, because they require human action to implement.

173:[174:] Certain classes of laser products are regulated around the world. Regulations and licensing requirements may cover activities such as importing, exporting, distributing, demonstrating, installing, servicing, and using these laser products.

26.3 The equipment supplier should provide the following in the operation and maintenance manuals:

a description of laser-related hazards present during operation, maintenance, or service, and methods to minimize the hazard;

justification for any procedures that require a laser controlled area and the dimensions of this hazard zone;

administrative controls used in maintenance and service activities; and

a description of necessary personal protective equipment.

26.4 The following detailed information should be available for the evaluator:

justification for when engineering controls are not feasible to limit exposure during operation or maintenance tasks, and how administrative controls provide equivalent protection (see § 26.2 ); and

documentation showing compliance with an appropriate international laser product safety or industry standard, or the national standard for country of use.

27 Sound Pressure Level27.1 Equipment should be designed to control exposures to sound pressure levels equal to or greater than 80 dBA continuous or intermittent sound pressure level, and 120 dB instantaneous (impulse) sound pressure level.

174:[175:] It is recommended that efforts be made to decrease sound pressure levels as they approach 80 dBA (i.e., 77 to 80 dBA), due to the additive sound pressure level effects of multiple pieces of equipment in the same vicinity.

27.2 The order of preference for controlling exposures is as follows:

27.2.1 Engineering Controls (e.g., source sound pressure level reduction, absorption, enclosures, barriers, acoustic dampening) — At a minimum, the design of the engineering controls should consider the sound pressure levels and type, the frequency, and the appropriate control technologies.

27.2.2 Administrative Controls — Acceptable administrative controls should be limited to supplemental hazard warning labels and operating procedures.

175:[176:] Noise labeling is typically implemented as signs located in the users facility.

SEMI S2-0818E © SEMI 1991, 2018 50

27.3 Sound level surveys should be conducted by the manufacturer during equipment development for equipment that may emit hazardous sound pressure levels.

27.3.1 The survey should be conducted in accordance with a recognized standard. In addition, the following test criteria should be applied:

27.3.1.1 The equipment mode of operation during the sound pressure level tests should simulate as closely as possible the actual modes and operating positions that may be experienced by the equipment user.

27.3.1.2 Measurements should be taken in locations that best simulate actual positions of operators relative to the equipment. As a general guideline, the microphone should be traversed 1 meter from the equipment, 1.2 meters above the ground to simulate seated operators, 1.5 meters above the ground to simulate standing operators, and 3.5 meters (or as far as possible) away from the nearest walls or sound-reflecting objects. Measurements are taken 360° around the equipment wherever possible.

176:[177:] Background level may be subtracted using an accepted method. If the sound pressure level difference is less than 3 dBA, the contribution of the source from the background cannot be adequately distinguished and the survey results would not be valid for values over 80 dBA.

Table 2 Sound Pressure Level Test Criteria

Difference between sound pressure level measured with noise source operating and background sound

pressure level (dBA)

Correction to be subtracted from the sound pressure level measured with the noise source operating to obtain the sound pressure level due to noise

source alone (dBA)

3 34 2.55 1.76 1.37 18 0.89 0.6

10 0.4

27.3.2 If the measured sound pressure level is less than 70 dBA, the manufacturer should provide to the evaluator test data documenting sound pressure levels, survey equipment, equipment calibration, test conditions and results.

27.3.3 If the measured sound pressure level is greater than 70 dBA, the test data should include all of the information in § 27.3.2 , and should also include the expected duration of personnel exposure.

27.3.4 If measured sound pressure level is greater than 75 dBA, information should be provided in the equipment maintenance manual describing the sound pressure level(s) and location(s).

28 Related Documents28.1 The following documents are sources of principles and practices of ventilation design.

28.1.1 ACGIH, “Hazard Assessment and Control Technology in Semiconductor Manufacturing.” (1989): distributed by Lewis Publishers, Chelsea, Michigan.

28.1.2 ANSI/AIHA® 34 Z9.5-1992 Standard — Laboratory Ventilation

28.1.3 Burgess, Ellenbecker, Treitman, “Ventilation for Control of the Work Environment.” John Wiley, NY (1989).

28.1.4 Burton, D.J., IVE, Inc., “Industrial Ventilation Workbook.” 3rd Edition, 1995, Lab Ventilation Workbook, (1994): 2974 South Oakwood, Bountiful, Utah 84010.34 American Industrial Hygiene Association, Suite 777 3141 Fairview Park Drive Falls Church VIRGINIA 22042 AIHA trademark is owned by American Industrial Hygiene Association.

51 SEMI S2-0818E © SEMI 1991, 2018

28.1.5 NFPA 45 — Fire Protection for Laboratories Using Chemicals

28.1.6 Williams, M., and D.G. Baldwin, “Semiconductor Industrial Hygiene Handbook.” Noyes Publications, Park Ridge, NJ (1995): ISBN 0-8155-1369-0.

SEMI S2-0818E © SEMI 1991, 2018 52

APPENDIX 1DESIGN GUIDELINES FOR EQUIPMENT USING LIQUID CHEMICALS — Design and Test Method Supplement Intended for Internal and Third Party Evaluation UseNOTICE: The material in this Appendix is an official part of SEMI S2 and was approved by full letter ballot procedures on December 15, 1999.

A1-1 IntroductionA1-1.1 This Appendix provides specific technical information relating to § 23 . In general, it provides information on potential hazards, recommended control methods, and design considerations.

A1-1.2 This Appendix is not intended to limit hazard evaluation methods or control strategies (e.g., design principles) employed by manufacturers. Alternative methods are acceptable if they provide an equivalent level of hazard control.

A1-1.3 This Appendix is intended to be used as a starting point for reference during equipment design. An example would be during a formal hazard analysis in a brainstorming session.

Table A1-1

Potential Hazard Recommended Control Method Design Considerations

Exposure to operators

Containment, control, and alarm notification for spills, leaks or vapors.

Appropriately sized secondary containment (minimum 110% volume of entire contents).Equipment exhaust.Leak sensors to initiate auto shutdown.

Controlled access to chemical containment areas.

Door/access cover interlocks that automatically depressurize the area of the system being accessed.

Control of access to point-of-operation hazards.

Physical guarding/presence-sensing devices.

Exposure to maintenance personnel

Control of chemical delivery pressure; control of residual chemicals.

Depressurization upon system failure, interlock activation, or normal shutdown.Transparent doors/covers allow visual inspection.

Serviceability Built-in system purge and flush capabilities.System components accessible and easy to service.

General equipment and component failure

Chemical resistance/compatibility Appropriate materials used for equipment construction and components.

Pressure rating Pressurized systems designed to withstand 150% of maximum foreseeable pressure, or provide a suitable relief valve.

Chemical delivery system leak

Durable bulk chemical containers Use of approved (e.g., DOT, UN Dangerous Goods) containers in bulk distribution systems.

Control of pressurized vessels and piping.

Provide visual pressure indicators with or without alarms.Pressurized vessels and piping are designed and built to recognized standards.

Spill control Automatic system pressure check prior to allowing dispense.Use of normally closed valves on distribution lines.

Drum change-out controls Over-fill sensors on chemical baths.Monitoring for excess flow.Keyed and color-coded quick-connects.

53 SEMI S2-0818E © SEMI 1991, 2018

Potential Hazard Recommended Control Method Design Considerations

Fire Control of ignition sources. NFPA 70® 35 (NEC® 36) Class I, Div. 2 wiring methods, intrinsically safe components, or nitrogen-purged enclosures.Physical separation of ignition sources and/or potentially flammable atmospheres.Use of low voltage to reduce the risk for ignition.

Control of static electricity (i.e., one type of ignition source).

Maintain ground continuity.

Heat/fire/chemical detectionLimiting concentrations of fuels and oxidizers.

(No consensus for a specific recommendation at the time of publication of this Safety Guideline.)

35 NFPA 70 trademark is owned by National Fire Protection Association, Inc.36 NEC trademark is owned by National Fire Protection Association, Inc.

SEMI S2-0818E © SEMI 1991, 2018 54

APPENDIX 2IONIZING RADIATION TEST VALIDATION — Design and Test Method Supplement Intended for Internal and Third Party Evaluation UseNOTICE: The material in this Appendix is an official part of SEMI S2 and was approved by full letter ballot procedures on December 15, 1999.

A2-1 IntroductionA2-1.1 This Appendix provides specific technical information relating to § 24 . In general, it provides information on hazard evaluation methods, examples of control strategies, and test validation criteria.

A2-1.2 This Appendix is not intended to limit hazard evaluation methods or control strategies (e.g., design principles) employed by the manufacturers. Alternative methods are acceptable if they provide an equivalent level of hazard control.

A2-1.3 Test validation criteria are generally referenced from the applicable internationally recognized standard. It is the users responsibility to ensure that the most current revision of the standard (or its national equivalent) is used.

Table A2-1

Ionizing Radiation Type

Emission Limitmicrosievert/hour(millirem/hour)

Test Method

X or Gamma Operator2 µSv/hour

(0.2 mrem/hour)

Direct doserate measurement with an Ion Chamber (or equivalent) calibrated to ±10% of true doserate at the surface of the equipment (or at the closest approach) in all areas where the operator may have access with the ionizing radiation source active.

X or Gamma Maintenance and Service10 µSv/hour

(1 mrem/hour)

Direct doserate measurement with an Ion Chamber (or equivalent) calibrated to ±10% of true doserate during simulated maintenance and service procedures. Measurements should be made at the surface emitting the ionizing radiation or the closest approach to the emitting surface with the ionizing radiation source active.NOTE: For these measurements, panels and/or shields should be removed only if removal is required for maintenance or service activities.

A2-2 Basic Radiation Control MethodsA2-2.1 Time — If the radiation field exists and it must be entered, then minimize the time spent in the field to minimize the exposure to the individual. This gives a linear dose reduction.

A2-2.2 Distance — If the radiation field is present, stay as far away from the source as possible to perform the required tasks. Dose is reduced by the square of the distance from the source.

A2-2.3 Shielding — If the radiation field is intense and the source is small, shielding the source is generally the most practical.

A2-2.4 Quantity — If there exists an opportunity to minimize the amount of radiation or radioactive material that is required for the task, then the exposure can be minimized also.

55 SEMI S2-0818E © SEMI 1991, 2018

APPENDIX 3EXPOSURE CRITERIA AND TEST METHODS FOR NON-IONIZING RADIATION (OTHER THAN LASER) AND ELECTROMAGNETIC FIELDSNOTICE: The material in this Appendix is an official part of SEMI S2 and was approved by full letter ballot procedures on December 24, 2011.

A3-1 IntroductionA3-1.1 This Appendix provides exposure criteria and test methods. The test methods are intended to be used for evaluation by and for equipment manufacturers. This Appendix is not attempting to provide field survey methods for semiconductor device manufacturing facilities.

A3-1.2 This Appendix provides specific technical information relating to § 25 . In general, it provides exposure limit criteria and test methods.

A3-1.3 This Appendix is not intended to limit risk control strategies (e.g., design principles) employed by manufacturers. Alternative methods are acceptable if they provide an equivalent level of risk control.

A3-2 Non-Ionizing Radiation SurveysA3-2.1 Non-ionizing radiation surveys should be conducted at the maximum operational power level and at all applicable frequencies (i.e., the frequencies of the non-ionizing emission sources that could approach the emission limits in the following tables). If the limit criteria incorporate a time of exposure aspect that is affected by the configurable process recipe of the equipment, the relevant recipe details should be documented in the evaluation report.

A3-2.1.1 If the equipment has one operating power level for the non-ionizing emission source, then the maximum operational power level is that level. Many types of non-ionizing emission sources on SME can be set at multiple power levels depending on the desired process results on the substrate. The maximum operational power level should then be chosen as the highest power level the equipment can run at, which is often set as a software limit to avoid equipment damage.

A3-2.2 Measurements should be made using the Test Methods as indicated in Table AA3-2.5.1.1 Table A3-1 , at the exterior surfaces of the equipment and at locations in which maintenance and repair personnel could encounter emissions, whenever practical (electric field measurements with paddle-shaped sensors may not be possible in some places due to the size and shape of the sensor).

A3-2.3 Measurements to assess electromagnetic emissions from equipment against the criteria in the following tables should be made in an environment that is reasonably free of energy of the wavelengths/frequencies of interest (i.e., the tool emissions at frequencies that approach the limit values during the measurements can be distinguished from the ambient environment), especially if the energy fluctuates in a manner that is unpredictable. This should be determined by conducting surveys in the test area before the equipment to be tested is set up and emitting for the planned measurements and preferably before the equipment is energized.

A3-2.4 Instruments used for the measurements described in this Appendix should be calibrated at a facility capable of calibrating such instruments using standards traceable to the National Institute of Standards and Technology (NIST) in the USA or an equivalent standards agency elsewhere, and in accordance with the guidance of the instrument manufacturer.

A3-2.5 Measurements taken for evaluation against the criteria of the following tables can be combined with measurements taken to address electromagnetic interference concerns. The specific measurement locations may differ between measurements taken to evaluate electromagnetic interference concerns and the measurements taken to address the concerns of the tables in this Appendix.

A3-2.5.1 The entries in Tables ATable A3-1 and AA3-3.1.1.1 Table A3-1 that begin with an ‘=’ are functions of the frequency (f) of the nonionizing radiation. The units are provided in ‘[]’ to clearly indicate the units for the frequency (f) that are called for by the indicated version of the formula.

SEMI S2-0818E © SEMI 1991, 2018 56

Table A3-1 Non-Ionizing Radiation

Energy Category Physical Quantity Measured

(units)

Operator-, Maintenance- and Service-Accessible

Limit

Medical Device Labeling Level

Testing Methods

Static#4

0 Hz.(e.g., static

magnets in motors or etch/implant

equipment)

Magnetic Flux

Density#1, #2

(Tesla or Gauss)

Head and torso200 mT(2000 G)

Limbs2 T

(20,000 G)#5

0.5 mT(5 G)

Use a Hall effect probe at each location (use three axis probe or make three mutually orthogonal measurements at each location).Measure field 2–3 cm (~1 in.) from the exterior surfaces of equipment and at maintenance and service locations. Locate 0.5 milliTesla line to place a medical device hazard alert label and 3 milliTesla line to identify where there is the risk of flying objects (for example, tools) and dislocations of magnetizable prostheses.

Sub Radio-frequency#1

1 Hz to 3 kHz(e.g., electro-

magnets in etch equipment)

Electric Field Strength#1

(V/m)

1–100 Hz5 kV/m

1 kV/m Use a displacement sensor.Determine the maximum field strength and orientation 2–3 cm (~1 in.) from the surface of the equipment.Remove field perturbations by using a long non-conductive handle extension or remote fiber optic readout.Locate 1 kV/m line to post medical device warnings.

100 Hz to 3 kHz= 500 [kV∙Hz /m] / f

1 kV/m

Sub Radio-frequency#1, #4

1 Hz to 3 kHz(e.g., electro-

magnets in etch equipment)

Magnetic Flux

Density#1, #2 (T or G)

orMagnetic

Field Strength (A/m)

1–300 Hz= 12 [mT∙Hz] / f

0.1 mT(1 G)

Use a loop sensor at each location (use three axis probe or make three mutually orthogonal measurements at each location). The sensor should be 2–3 cm (~1 in.) from the equipment surface.Identify 0.1 milliTesla line to post medical device warnings.

300 < 628.5 Hz0.04 mT (400 mG)

0.1 mT(1 G)

628.5 ≤ 820 Hz= 25.14 [mT∙Hz] / f

0.1 mT(1 G)

820 Hz – 3 kHz0.031 mT (310 mG)

0.1 mT(1 G)

Radio-frequency Field#2

3 kHz to 100 kHz(e.g., RF used to generate plasma)

Induced current#3

(mA)

both feet = 400 [mA/MHz] × f

each foot = 200 [mA/MHz] × f

N/A Contact instrument vendor for suitable instrument based on frequency and emission characteristics.Measurement of induced currents should be made when the electric and magnetic field measurements for these frequencies approach the accessible limits.#4

Radio-frequency Field#2

3 kHz to 100 kHz(e.g., RF used to generate plasma)

Contact current(mA)

= 90 mA/MHz × f N/A Contact instrument vendor for suitable instrument based on frequency and emission characteristics.Measurement of contact currents should be made when the electric field approaches the applicable electric field accessible limit.#4

Radio-frequency Field#2

100 kHz to 100 MHz

(e.g., RF used to generate plasma)

Induced current#3

(mA)

both feet = 40 mAeach foot = 20 mA

N/A Contact instrument vendor for suitable instrument based on frequency and emission characteristics.Measurement of induced currents should be made when the electric and magnetic field measurements for these frequencies approach the accessible limits.#4

57 SEMI S2-0818E © SEMI 1991, 2018

Energy Category Physical Quantity Measured

(units)

Operator-, Maintenance- and Service-Accessible

Limit

Medical Device Labeling Level

Testing Methods

Radio-frequency Field2

100 kHz to 100 MHz

(e.g., RF used to generate plasma)

Contact current(mA)

9 mA N/A Contact instrument vendor for suitable instrument based on frequency and emission characteristics.Measurement of contact currents should be made when the electric field approaches the applicable electric field accessible limit.#4

#1 It is assumed that electric and magnetic fields exist separately at frequencies below 300 MHz. It is assumed that electric and magnetic fields exist as a combined entity (electromagnetic radiation) at higher frequencies. Two measurements are needed at frequencies <300 MHz and only one (usually made by measuring the electric field) at higher frequencies.#2 1 gauss (G) 79.55 amperes per meter (A/m). 1 tesla (T) = 10,000 G, 1 millitesla (mT) = 10 G.#3 Limit values are given for one and both feet as a) the reference standards provide similar limits and b) different types of induced current test equipment measure using both methods.#4 See ¶ 25.2.1 for limitations on using the partial body exposure limit.

A3-3 RF Emission LimitsA3-3.1 The equipment RF emission limits are given in Table AA3-3.1.1.1 Table A3-1 .

Table A3-1 Radiofrequency Emission Limits

Frequency Radiofrequency Emission Limits

E-Field (V/m)#1 H-Field (A/m)#2 S#3 (W/m2)#4

3 kHz to 65 kHz 122.8 24.465 kHz to 3 MHz 122.8 = 1.6 [A∙MHz /m] / f3 MHz to 10 MHz = 368.4 [V∙MHz /m] / f = 1.6 [A∙MHz /m] / f

10 MHz to 20.375 MHz = 368.4 [V∙MHz /m] / f 0.1620.375 MHz to 30MHz = 368.4 [V∙MHz /m] / f = 3.26 [A∙MHz /m] / f30 MHz to 100 MHz 12.28 = 3.26 [A∙MHz /m] / f

100 MHz to 300 MHz 12.28 0.0326300 MHz to 400 MHz 12.28 0.0326 2

400 MHz to 2 GHz = f / (200 [m2∙MHz /W])2 GHz to 100 GHz 10

100 GHz to 122.22 GHz = ((9 [W/GHz]) f − 700 [W])/20 m2

122.22 GHz to 300 GHz 20#1 E-field criteria are derived from the IEEE C95.1-1999 controlled environment criteria. A 20% multiplier has been continued from previous versions of this standard. The 1999 revision was used as it still provides emission criteria for the frequency band between 3 and 100 kHz, which is not provided in the 2005 revision.#2 H-field criteria are derived from a combination of 2004/40/EC EU Worker Protection Directive for Electromagnetic fields and IEEE C95.1-1999 controlled environment criteria, continuing the previously used 20% multiplier for the IEEE criteria. The 1999 revision was used as it still provides emission criteria for the frequency band between 3 and 100 kHz, which is not provided in the 2005 revision.#3 Power Density (S) criteria are derived from the IEEE C95.1-2005 uncontrolled environment (a.k.a. general public) criteria below 122.22 GHz and continuing the 20% multiplier of the IEEE C95.1-2005 controlled environment criteria above 122.22 GHz.#4 At higher frequencies and thus shorter wavelengths, the RF emissions are in the far field, and can be measured in W/m2. This measures the power density of the RF emissions.

SEMI S2-0818E © SEMI 1991, 2018 58

A3-3.1.2 It is recommended that these limit values be used as ceiling values, however, it is acceptable to use these values as average values if adequate documentation of how the average value is calculated is provided in the finding justification. When these are used as average values, the averaging time used should be taken from the Action level /general public/uncontrolled environment table in IEEE C95.1.

177:[178:] Most RF monitoring equipment does not provide an average reading but a relatively instantaneous reading, therefore, the method used to generate these averaged values would need to be documented along with the update frequency of the monitoring equipment and expected time variations of the RF field (for example due to equipment process recipe changes in RF generator output power).

A3-3.2 Measurement Techniques

A3-3.2.1 Near-Field vs. Far-Field — The cost of semiconductor manufacturing cleanroom space forces the equipment to be installed as close as possible to other equipment. Therefore, to accurately measure the potential exposure to personnel within a cleanroom environment for frequencies below 300 MHz, most of the measurements must be made within the near-field or transition zone between the near and far-field. In the far field, the relationship between the E-field and H-field is constant, allowing for one measurement for both fields. In the near field, the relationship between the E and H-fields is not constant, therefore each must be measured. Additionally, the field strength in the near field is more likely to vary significantly within small distances than it does in the far field.

A3-3.2.2 Many meters designed to measure RF emissions reduce cost by including only the capability to measure one field and assume that the measurements are made in the far field to provide the other values based on the constant relationship. Such meters are not generally acceptable for use for measurements of frequencies below 300 MHz against these criteria, unless it can be shown that for the measurements under consideration, the measurement is fully in the far-field (generally considered to be beyond two wavelengths) and thus the constant relationship assumptions are valid.

A3-3.2.3 As much as possible, test the equipment in an environment that is relatively free of other RF emissions in the same frequency bands.

A3-3.2.4 Measurement distance from the edge of the equipment should in general be at least 20 cm (8 in.). Maintenance and service exposure should be evaluated at the locations where the personnel will perform the maintenance and service on the equipment (as can be best approximated with the size of the probe).

178:[179:] The distance is to avoid capacitive coupling of the measurement probe with the source distorting the measurements.

A3-3.2.5 For test personnel safety and to evaluate the highly variable near field region adequately, the measurement probe should be powered on at a distance from the equipment and the fields should be evaluated for variations in three cardinal directions (towards and away from the equipment, laterally and vertically along the equipment) looking for the highest values. This will help both to avoid unsafe levels of RF energy for the test personnel and to determine if there are RF leaks at connections, enclosures or cabling that need to be fixed, as these can cause very localized or strangely-shaped RF fields within and around the equipment.

179:[180:] For equipment using RF generated plasma to etch or deposit materials on the substrate, it is likely that the process requirements for consistent plasma will drive RF control much more stringently than is required to meet the personnel safety criteria. In such cases, this sampling may detect emissions only very close to the equipment or when the equipment is having problems processing the substrates consistently (possibly indicating a bad connection or impedance mismatch in the RF delivery path). The concerns of ¶ AA3-3.2.5 are most relevant when the use of the RF energy is not as strictly controlled as it is in etch or plasma deposition equipment.

A3-3.2.6 For complex testing conditions or where significant harmonics are foreseen (e.g., when the RF cables are warm), it is recommended to conduct the equipment EMC radiated emissions testing (e.g., with an antenna and oscilloscope or spectrum analyzer) to identify the appropriate frequencies to evaluate before doing field strength testing.

A3-3.2.7 For complex testing conditions or additional information, see IEEE C95.3 (as indicated in the references section) for additional information.

A3-4 Optical RadiationA3-4.1 There are multiple safety concerns related to the effects of optical radiation on the skin and multiple tissues in the eyes. This Document is not addressing skin concerns as there is very little exposed skin in a semiconductor

59 SEMI S2-0818E © SEMI 1991, 2018

fabrication cleanroom environment, and the eyes are more sensitive than the skin. The concerns and associated wavelengths are listed in Table AA3-4.3.1.1 Table A3-1 .

A3-4.2 All of the accessible limits are summation limit functions, meaning that they add up the relative contributions of the various wavelengths of the optical energy source. Therefore, the optical source should be evaluated to all of the limits for which the optical energy source has significant emissions.

[A3-4.3 ] The equipment emission limit for this Document are the exposure limit value from the most recent version of the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs®) and Biological Exposure Indices (BEI® 37s®) book with the measurement distance from source and time considerations given below.

180:[181:] The European Union (EU) Worker Protection directive for artificial optical radiation (e.g., 2006/25/EC) provides similar worker exposure criteria for the EU countries. There are some differences in the retinal thermal hazard weighting values [R(λ)], further focusing the criteria towards 380 to 495 nm energy.

Table A3-1 Optical Radiation Concerns

Approximate Wavelengths Safety / Tissue Concern Measurement

180 to 400 nm (Broadband UV)

Corneal and lenticular hazard Effective (weighted by relative Spectral Effectiveness [S(λ)] weighting function) irradiance weighted towards 255 to 295 nm

315 to 400 nm (UV-A)

Lenticular and retinal hazard Irradiance

300 to 700 nm (‘Blue light’, UV-A and

visible)

Photochemical retinal hazard Effective (weighted by blue light hazard [B(λ)] weighting function) irradiance & radiance weighted towards 415 to 475 nm

380 to 1400 nm (visible and IR-A)

Thermal retinal hazard#1 Effective (weighted by retinal thermal hazard [R(λ)] weighting function) radiance weighted towards 415 to 850 nm

775 to 3000 nm (IR-A and IR-B)

Thermal corneal and lenticular hazard

Irradiance

#1 The thermal retinal hazard has different limit criteria depending on whether there is a significant visible light component to cause constriction of the pupil.

A3-4.3 [A3-4.4 ] Measurement Techniques and Limit Value Guidance

A3-4.3.1 [A3-4.4.1 ] Meters and Measuring — There are two viable methods for measuring accessible emissions against the limits.

A3-4.3.1.1 [A3-4.4.1.1 ] One can directly measure radiance or irradiance for the specific frequency bands directly, multiply the irradiance by the weighting function value (see the referenced documents) and sum the exposure values for the bands against the limit value per the functions, or

A3-4.3.1.2 [A3-4.4.1.2 ] Use a meter that has the specific weighting function built-in and taking the emission value directly from the meter.

A3-4.3.1.3 [A3-4.4.1.3 ] While the former method can be more accurate in a controlled laboratory environment, the latter is much more practical and is the recommended method in the evaluation setting that is typical for semiconductor equipment evaluations.

A3-4.3.2 [A3-4.4.2 ] Measurement Distance from Source — As radiance [typical units being W/(m2sr)] is a characteristic of the source and not of the target location, radiance measurements may be made at any convenient location. Irradiance measurements (measurements of radiation striking the target, typical units being W/m 2) (see Table AA3-4.3.1.1 Table A3-1 for which concerns/wavelengths require radiance measurements) should be made at the accessible location closest to the source (e.g., at the view window). If the exposure is reasonably foreseeable only as part of a maintenance or service task, then the emissions should also be measured where the expected exposure will occur (e.g., the expected location of the person performing the maintenance task) if the measurement at the closest location is near or above the referenced accessible limits.

37 BEI trademark is owned by American Conference of Governmental Industrial Hygienists, Inc.

SEMI S2-0818E © SEMI 1991, 2018 60

EXCEPTION: Accessible emission levels per § AA3-4.4.2 for exposures that are only part of maintenance and service tasks and meet the emission limits at the reasonably foreseeable exposure location, but not at locations closer to the source are acceptable if:

a) a good justification that personnel are either unable or have no viable reason to get closer to the emission source is included in the SEMI S2 report,

b) the documents provided to the user describe the distance limit both in the general safety section or equivalent (e.g., a list of equipment locations with emissions that exceed the indicated limits) and in the task specific section(s) where exposure is possible, and

c) the optical radiation hazard alert label (see ¶ 25.5 ) indicates the minimum distance requirement and this label is visible before entering within the area that exceeds the emission limit.

A3-4.3.3 [A3-4.4.3 ] Time Considerations

A3-4.3.3.1 [A3-4.4.3.1 ] If exposure potential is generally present (for example, leakage from an optical radiation source that is on whenever the equipment is energized), then the limit values calculated for an 8 hour exposure should be used. This is also the recommendation for all potential optical radiation exposures.

A3-4.3.3.2 [A3-4.4.3.2 ] If the exposure period occurs during only a portion of the scheduled maintenance task being evaluated, and the maintenance task foreseeably could be repeated during the work day, the total foreseeable exposure time can be calculated adding the actual exposure times over the course of the shift, assuming the same person is performing the task repeatedly during the work shift.

A3-4.3.3.3 [A3-4.4.3.3 ] Service and unscheduled maintenance tasks (e.g., replace when no longer meets the specification) should be evaluated depending on how the task is likely to be completed. Many unscheduled or service tasks (e.g., part replacement upon failure) can reasonably be expected to occur no more than once daily, and could be evaluated as shown in ¶ AA3-4.4.2 with a number of tasks per day equal to 1. Equipment upgrade tasks that can be repeated within a workday can be evaluated using the method of the previous paragraph.

A3-4.3.3.4 [A3-4.4.3.4 ] If an exposure time of less than 8 hours is used in the evaluation, the justification for the shorter exposure time used for the evaluation should be clearly documented in the evaluation report. Additionally, if the exposure rate exceeds the 8-hour exposure criteria, then a) the equipment manuals should describe the time of exposure limit both in the general safety section (e.g., a list of locations with less than an 8-hour allowable exposure) and in the task specific section(s) where exposure is possible, and b) the optical radiation hazard alert label (see ¶ 25.5 ) should indicate the maximum permissible exposure time.

A3-5 ReferencesA3-5.1 2010 TLVs and BEIs Threshold Limit Values for Chemical Substances and Physical Agents Biological Exposure Indices, ACGIH, Cincinnati, OH (republished annually).

A3-5.2 IEEE C95.1-1999 — Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electro-magnetic Fields, 3 kHz to 300 GHz

A3-5.3 Guidelines on Limits of Exposure to Broad-Band Incoherent Optical Radiation (0.38 to 3 µM), Health Physics Vol. 73, No. 3 (September 1997): pp. 539–554.

[A3-5.4 ] Directive 2004/40/EC on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (electromagnetic fields), (30 April 2004), Official Journal of the European JournalUnion, (April 27, 2006): pages L 184/1 through L 184/9.

A3-5.4 [A3-5.5 ] Directive 2006/25/EC on the minimum health and safety requirements regarding exposure of workers to risks arising from physical agents (artificial optical radiation), (5 April 2006), Official Journal of the European Journal, (April 27, 2006): pages L 114/38 through 114/59.

A3-5.5 [A3-5.6 ] IEEE C95.1-2005 — IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electro-magnetic Fields, 3 kHz to 300 GHz

A3-5.6 [A3-5.7 ] IEEE C95.3-2002 — IEEE Recommended Practice for Measurements and Computations of Radio Frequency Electromagnetic Fields with Respect to Human Exposure to Such Fields, 100 kHz to 300 GHz

61 SEMI S2-0818E © SEMI 1991, 2018

APPENDIX 4FIRE PROTECTION: FLOWCHART FOR SELECTING MATERIALS OF CONSTRUCTIONNOTICE: The material in this Appendix is an official part of SEMI S2 and was approved by full letter ballot procedures on December 15, 1999.

SEMI S2-0818E © SEMI 1991, 2018 62

APPENDIX 5LASER DATA SHEET — SEMI S2NOTICE: The material in this Appendix is an official part of SEMI S2 and was approved by full letter ballot procedures.

A5-1 Equipment Information (All Laser Product Classes)Laser Equipment Manufacturer ____________________________________________________

Equipment Model # ________________________

Date Laser Data Sheet Completed ________________

Laser Product Classification ____________ (e.g., 1, 1M, 2, 2M, 3A, 3R, 3B, 4)

Classification Standard(s) ____________ (e.g., IEC, FDA/CDRH, JIS)

Certification File Identification Number ______________(e.g., CDRH accession number, or if CDRH accession number has been applied for, but not yet received, a statement of ‘pending’ along with the submittal date may be used instead). If self-declaring under IEC 60825-1 or if certification is not required (e.g., if class 1 laser product is incorporated without changes, then ‘N/A’ may be used).

A5-2 Laser Information (Greater than Class 2 and embedded Class 3R (3A), 3B and 4)Is access to laser radiation above the maximum permissible exposure (MPE) level YES NOrequired during maintenance or service tasks? ____ _____

If NO, then the information in Parts AA5-2 , AA5-3 and AA5-4 need not be provided.

If YES, complete the information in Parts AA5-2 , AA5-3 and AA5-4 for each task and laser that requires access.

If there are multiple lasers contained within the laser equipment, provide the following for each task/laser combination that meets the above criteria.

Laser Parameters Laser ___1___, ___2___, __etc.__

Laser Manufacturer _______, _______, _______

Laser Model No. _______, _______, _______

A5-2.1 Laser Medium Type (HeNe, Nd:YAG, Argon, KrF, Diode, etc.) _______, _______, _______

A5-2.2 Wavelength(s) in nanometers (nm) _______, _______, _______

A5-2.3 Laser Hazard Classification (individual laser) _______, _______, _______

181:[182:] If a laser is used in both continuous wave and pulsed modes, complete both § AA5-2.4 and § AA5-2.5 .

A5-2.4 Continuous Wave Lasers

A. Power in Watts (W) _______, _______, _______B. Irradiance in Watts/square centimeter (W/cm2 at aperture) _______, _______, _______

A5-2.5 Pulsed Laser Characteristics

A. Pulse Duration in Seconds (s) _______, _______, _______B. Energy per Pulse in Joules (J) _______, _______, _______C. Pulse Repetition Frequency in Hertz (Hz) _______, _______, _______D. Average Power in Watts (W) _______, _______, _______E. Radiant Exposure Joules/square centimeter (J/cm2) _______, _______, _______F. Q-Switch controlled pulses (Yes/No) _______, _______, _______

63 SEMI S2-0818E © SEMI 1991, 2018

A5-2.6 Beam Parameters at Maintenance or Service Access Points

EXCEPTION: In the case of proprietary information, an acceptable alternative to providing the Beam Parameters is to provide NOHD results for each access point according to IEC 60825 or equivalent.

A. Beam shape Circular (C), Rectangular (R), Elliptical (E) _______, _______, _______B. Beam size (mm) Major axis (R/E) or diameter (C) _______, _______, _______

Minor axis (R/E) _______, _______, _______Laser Parameters Laser ___1___, ___2___, __etc.__

C. Beam divergence in milliradians (mr)Major axis (R/E) or diameter (C) _______, _______, _______Minor axis (R/E) _______, _______, _______

D. Focal length in millimeters (mm) (of the emitting lens)Major axis (R/E) or diameter (C) _______, _______, _______Minor axis (R/E) _______, _______, _______

E. Is there a collecting optics hazard? (Yes/No) _______, _______, _______

A5-3 Laser Control MeasuresA5-3.1 Specify maintenance/service tasks requiring access to laser radiation in excess of the MPE and recommended laser control measures.

A. Task 1 ________________________________________________________________B. Task 2 ________________________________________________________________C. Etc. ________________________________________________________________

182:[183:] Suppliers may alternately provide a reference to laser control measures information that is located in a document available to users.

A5-3.2 Of the tasks in § AA5-3.1 , which tasks need a Laser Controlled Area (for Class 3b or 4 lasers)?

_______________________________________________________________________________

A5-3.3 If a nominal ocular hazard distance (NOHD) is used as a control measure, then provide the NOHD calculations and assumptions. See IEC 60825-1 for NOHD calculations.

EXCEPTION: If specific information required by § AA5-2.6 is proprietary, suppliers may provide the NOHD results and an explanation of the assumptions made.

A5-3.4 Include a beam path diagram identifying the accessible points.

183:[184:] A description of the access points from the exterior of the tool can be considered equivalent to a diagram.

A5-4 Personnel Protective Equipment (PPE)Provide information for accessible laser radiation hazards in excess of the Maximum Permissible Exposure (MPE)

Laser Parameters Laser ___1___, ___2___, __etc.__A. Optical Density (OD) of PPE required during maintenance _______, _______, _______B. OD of PPE required during service activities _______, _______, _______C. Other types of PPE (e.g., skin protection) if needed _______, _______, _______

184:[185:] Suppliers may alternately provide a reference to PPE information located in a document available to users.

SEMI S2-0818E © SEMI 1991, 2018 64

185:[186:] The Related Information Index that was shown here following Appendix APPENDIX 5 has been relocated to the front of the main part of the Document into the Table of Contents.

65 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 1 EQUIPMENT/PRODUCT SAFETY PROGRAMNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R1-1 PrefaceR1-1.1 Compliance with design-based safety standards does not necessarily ensure adequate safety in complex or state-of-the-art systems. It is often necessary to perform hazard analyses to identify hazards that are specific to the system, and develop hazard control measures that adequately control the associated risk beyond those that are covered in existing design-based standards. This Document provides guidelines for developing a deliberate, planned equipment/product safety (EPS) program integrating the compliance assessment activities with hazard analyses and other activities needed to provide a safe system throughout the life of equipment or products.

R1-1.2 An effective EPS program reduces the cost, schedule slips, and liability associated with the late identification and correction of hazards. To be most effective, an EPS program should be begun by the manufacturer early during the design phase. Starting early allows safety to be designed into the system and its subsystems, equipment, facilities, processes, procedures, and their interfaces and operations. These guidelines are designed to assist the manufacturer in planning and implementation of an effective EPS program.

R1-1.3 The lowest costs for implementing safety can be achieved when hazards are identified and resolved before hardware is built and firmware or software is coded. This guide is intended to provide the basis for a methodology for implementing a safety program for early and continued hazard identification and the elimination or reduction of associated risks.

R1-1.4 EPS program success depends directly upon management emphasis and support applied during the system design and development process and throughout the life cycle of the product. This emphasis should include the following management controls:

R1-1.4.1 Agreement from management that the EPS program will be maintained and supported throughout the product or facility life cycle;

R1-1.4.2 Clear and early statements of agreement with EPS objectives and requirements;

R1-1.4.3 Understanding of, and participation in, the risk acceptance process; and

R1-1.4.4 Continuing consideration of risk reduction during the management review process.

R1-2 PurposeR1-2.1 This Safety Guideline describes an approach for developing and implementing an EPS program of sufficient comprehensiveness to identify the hazards of a product and to develop design and administrative controls to prevent incidents. The EPS program addresses hazards from many sources to include system design, hazardous materials, advancing technologies, and new techniques. The goal is to eliminate hazards or reduce the associated risk to an acceptable level.

R1-3 ScopeR1-3.1 This Safety Guideline applies to every activity of the product life cycle (e.g., research, technology development, design, test and evaluation, production, construction, checkout/calibration, operation, maintenance and support, modification and disposal).

R1-4 General GuidelinesR1-4.1 EPS Program — The supplier should establish and maintain an EPS program to support efficient and effective achievement of overall EPS objectives. Depending upon the needs of the company, the EPS Program may be a companywide program covering all projects, separate programs for each project, or some combination of the two.

SEMI S2-0818E © SEMI 1991, 2018 66

R1-4.1.1 Management System — The supplier should establish an EPS management system to implement provisions of this Safety Guideline commensurate with the needs of the program. The program manager should be responsible for the establishment, control, incorporation, direction and implementation of the EPS program policies and should assure that risk is identified and eliminated or controlled. The supplier should establish internal reporting systems and procedures for investigation and disposition of product related incidents and safety incidents, including potentially hazardous conditions not yet involved in an incident.

R1-4.2 EPS Design Guidelines

R1-4.2.1 EPS design requirements should be specified after review of pertinent standards, specifications, regulations, design handbooks, safety design checklists, and other sources of design guidance for applicability to the design of the system. The supplier should establish EPS design criteria derived from applicable data including the preliminary hazard analyses. These criteria should be the basis for developing system specification EPS requirements. The supplier should continue to expand the criteria and requirements for inclusion in development specification during the subsequent program phases.

R1-5 Detailed GuidelinesR1-5.1 The purpose of the EPS program is to ensure that the equipment or product is designed and documented in a manner that reduces the safety risk associated with that equipment or product to a level that is acceptable to the customer. This consideration applies to all life cycle phases of the equipment or product. The following sections include detailed elements of a formal EPS program. Management should select or tailor the elements appropriate to their needs.

R1-5.2 EPS Program Plan (EPSPP) — The purpose of a EPS Program Plan (EPSPP) is to describe the tasks and activities of EPS management and engineering required to identify, evaluate, and eliminate/control hazards, or reduce the associated risk to an acceptable level throughout the system life cycle. The plan provides a basis of understanding of how to organize and execute an effective EPS program.

R1-5.2.1 EPS Program Scope and Objectives — Each EPSPP should describe, as a minimum, the following four elements of an effective EPS program:

a planned approach for task accomplishment,

qualified people to accomplish tasks,

authority to implement tasks through all levels of management, and

appropriate commitment of resources (both staffing and funding) to assure tasks are completed.

The scope and objectives should:

Describe the scope of the overall program and the related EPS program.

Identify the tasks and activities of EPS management and engineering functions. Describe the interrelationships between EPS and other functional elements of the program. Identify the other program requirements and tasks applicable to EPS.

Account for major required EPS tasks and responsibilities.

R1-5.2.2 EPS Function — The EPSPP should describe:

R1-5.2.2.1 The EPS function within the organization of the total program, including organizational and functional relationships, and lines of communication. Other functional elements that are responsible for tasks that impact the EPS program should be included. This description should include the integration/management of associate suppliers, subcontractors and engineering firms. Review and approval authority of applicable tasks by EPS should be described.

R1-5.2.2.2 The responsibility and authority of EPS personnel, other supplier organizational elements involved in the EPS effort, subcontractors, and EPS groups. Identify the organizational unit responsible for executing each task and the authority in regard to resolution of identified hazards.

R1-5.2.2.2.1 One highly effective organizational approach to hazard resolution authority is through the use of an EPS Working Group (EPSWG). The activities of the EPSWG could include:

67 SEMI S2-0818E © SEMI 1991, 2018

Identifying safety deficiencies of the program and providing recommendations for corrective actions or prevention of reoccurrence.

Reviewing and evaluating the hazard analyses to develop agreement that the hazards have been properly identified and controlled.

Provide recommendations to the proper level of management concerning the need for additional hazard controls and the acceptability of residual risks.

The staffing of the EPS function.

The procedures by which the supplier will integrate and coordinate the EPS efforts.

The process through which supplier management decisions will be made.

Details of how resolution and action relative to EPS will be affected at the program management level possessing resolution and acceptance authority.

R1-5.2.3 EPS Program Milestones — The EPSPP should include:

Identification of the major EPS program milestones. These should be related to major program milestones, program element responsibility, and required inputs and outputs.

A program schedule of EPS tasks, including start and completion dates, reports, and reviews.

Identification of subsystem, component, software safety activities as well as integrated system level activities (i.e., design analyses, tests, and demonstrations) applicable to the EPS program but specified in other engineering studies and development efforts to preclude duplication.

R1-5.2.4 General EPS Guidelines and Criteria — The EPSPP should:

Describe general engineering requirements and design criteria for safety.

Describe the risk assessment procedures (see SEMI S10). The hazard severity categories, hazard likelihood categories, and the EPS precedence that should be followed to satisfy the safety requirements of the program.

Describe closed-loop procedures for taking action to resolve identified unacceptable risks including those involving nondevelopmental items.

R1-5.2.5 Hazard Analysis — The EPSPP should describe:

The analysis techniques and formats to be used to identify hazards, their causes and effects, hazard elimination, or risk reduction requirements and how those requirements are met.

Recommended techniques for identification of hazards and hazard scenarios include Preliminary Hazard Lists, Preliminary Hazard Analysis, HAZOPs, FMEA, FTA, ‘what if?’ and process control analyses. Other types of hazard analysis techniques are discussed in a variety of sources, such as CEN EN 1050, Annex B. No single method is the best for all types of systems, subsystems, subsystem interaction or facilities. A combination of techniques may be most appropriate.

The integration of subcontractor or supplier hazard analyses and safety data with overall system hazard analyses.

Efforts to identify and control hazards associated with materials used during the system’s life cycle.

R1-5.2.6 System Safety Data — The EPSPP should describe the approach for collecting and processing pertinent historical hazard, incident, and safety lessons learned, data.

R1-5.2.7 Safety Verification — The EPSPP should describe:

The verification (test, analysis, inspection, etc.) methods to be used for making sure that safety are adequately demonstrated. Identify any requirements for safety certification, safety devices or other special safety verification or documentation requirements.

Procedures for transmitting safety-related verification information to the customer or others for review and analysis.

SEMI S2-0818E © SEMI 1991, 2018 68

R1-5.2.8 Audit Program — The EPSPP should describe the techniques and procedures to be employed to make sure the objectives and requirements of the EPS program are being accomplished.

R1-5.2.9 Incident Reporting — The supplier should describe in the EPSPP the incident alerting/notification, investigation and reporting process including notification of the customer.

R1-5.2.10 EPS Interfaces — The EPSPP should identify:

The interface between EPS and all other applicable safety disciplines.

The interface between EPS, systems engineering, and all other support disciplines such as: maintainability, quality control, reliability, software development, human factors engineering, and others as appropriate.

The interface between EPS and product design, integration and test disciplines.

R1-5.3 Hazard Analysis Documentation

R1-5.3.1 The hazard analysis process is used to identify hazards and their controls. This information should be documented in a closed loop tracking system to track the implementation of the controls and may also be required for presentation to management, the customer and others. The safety documentation could include a system description, the identification of hazards and their residual risks, as well as special procedures and precautions necessary for safety.

R1-5.3.2 The documentation should include the following:

R1-5.3.2.1 System Description — This should consist of summary descriptions of the physical and functional characteristics of the system and its components. Reference to more detailed system and component descriptions, including specifications and detailed review documentation should be supplied when such documentation is available. The capabilities, limitations and interdependence of these components should be expressed in terms relevant to safety. The system and components should be addressed in relation to its function and its operational environment. System block diagrams or functional flow diagrams may be used to clarify system descriptions. Software and its role(s) should be included in this description.

R1-5.3.2.2 Data — This should consist of summaries of data used to determine the safety aspects of design features.

R1-5.3.2.3 Hazard Analysis Results — This should consist of a summary or a total listing of the results of the hazard analysis. Contents and formats may vary according to the individual requirements of the program. The following data elements may be used for documenting the results of hazard analyses:

R1-5.3.2.3.1 System/Subsystem/Unit — The particular part of the system that is the concern in this part of the analysis. This is generally a description of the location of the component being considered.

R1-5.3.2.3.2 Component/Phase — The particular phase/component with which the analysis is concerned. This could be a system, subsystem, component, software, operating/maintenance procedure or environmental condition.

R1-5.3.2.3.3 Hazard Scenario Description — A description of the potential/actual hazards inherent in the item being analyzed, or resulting from normal actions or equipment failure, or handling of hazardous materials.

R1-5.3.2.3.4 Effect of Hazard — The detrimental effects that could be inflicted on the subsystem, system, other equipment, facilities or personnel, resulting from this hazard. Possible upstream and downstream effects can also be described.

R1-5.3.2.3.5 Recommended Action(s) — The recommended action(s) that are necessary and sufficient to eliminate or control the hazard. Sufficient technical detail is required in order to permit the design engineers and the customer to adequately develop and assess design criteria resulting from the analysis. Include alternative designs and life cycle cost impact where appropriate.

R1-5.3.2.3.6 Risk Assessment — A risk assessment for each hazard (classification of severity and likelihood). This may include an assessment of the risk prior to taking any action(s) to eliminate or control the hazard and a separate assessment of the risk following implementation of the Recommended Action(s) (see SEMI S10).

R1-5.3.2.3.7 Remarks — Any information relating to the hazard not covered in other blocks; for example, applicable documents, previous failure data on similar systems, or administrative directions.

69 SEMI S2-0818E © SEMI 1991, 2018

R1-5.3.2.3.8 Status — The status of actions to implement the recommended control, or other, hazard controls. The status should include not only an indication of ‘open’ or ‘closed,’ but also reference to the drawing(s), specification(s), procedure(s), etc., that support closure of the particular hazard. The person(s) or organization(s) responsible for implementation of the control should also be recorded.

SEMI S2-0818E © SEMI 1991, 2018 70

RELATED INFORMATION 2 ADDITIONAL STANDARDS THAT MAY BE HELPFULNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

Table R2-1

International Standards Title

IEC 60204-1 Safety of Machinery – Electrical Equipment of Machines – Part 1 General RequirementsIEC 60417 Graphical Symbols for Use on EquipmentIEC 60664 Insulation Coordination for Equipment within Low-Voltage Systems

IEC 60825-1 Safety of Laser Products, Part 1: Equipment Classification, Requirements and User’s Guide

IEC 60950 Safety of Information Technology Equipment, including Electrical Business EquipmentIEC 60990 Methods of measurement of touch current and protective conductor current

IEC 61310-1 Safety of Machinery – Indication, Marking and Actuation – Part 1: Requirements for Visual, Auditory and Tactile Signals

ISO 3461-1 General Principles for the Creation of Graphical Symbols – Part 1: Graphical Symbols for Use on Equipment

ISO 3864 Safety Colours and Safety SignsISO 7000 Graphical Symbols for Use on Equipment – Index and Synopsis

USA Standards Title

ANSI Z535.1–ANSI Z535.5 Labeling and MarkingANSI/UL 94 Tests for Flammability of Plastic Materials for Parts in Devices & AppliancesANSI/UL 499 Electric Heating ApplianceANSI/UL 508 Industrial Control EquipmentANSI/UL 991 Tests for Safety-Related Controls Employing Solid-State

UL 1012 Power Units Other than Class 2ANSI/UL 1778 UPS EquipmentANSI/UL 1950 Information Technology EquipmentANSI/UL 1998 Safety-Related Software

ANSI/UL 3101-1 Electrical Equipment for Laboratory Use; Part 1: General RequirementsANSI Z136.1 American National Standard for Safe Use of Lasers

ASTM® 38 Volume 10.03 Electrical Protective EquipmentISA S82.02 Electrical and Electronic Test and Measuring EquipmentISA S82.03 Electrical and Electronic Process Measuring and Control

Factory Mutual Data Sheet 7-7 Semiconductor Fabrication FacilitiesFMRC 3810 Electrical and Electronic Test, Measuring and Process Control Equipment

NFPA 70 National Electrical CodeNFPA 70E Electrical Safety Requirements for Employee WorkplacesNFPA 79 Electrical Standard for Industrial Machinery

NFPA 318 Standard for the Protection of CleanroomsNEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)

NEMA ICS 1.1 Safety Guidelines for the Application, Installation, and Maintenance of Solid-State Control

38 ASTM trademark is owned by American Society for Testing and Materials.

71 SEMI S2-0818E © SEMI 1991, 2018

USA Standards Title

OSHA 29 CFR 1910.132-138 Personal Protective EquipmentOSHA 29 CFR 1910.147 The control of hazardous energy (lockout/tagout)

OSHA 29 CFR 1910.332-335 Safety Related Work Practices [electrical]1997 Uniform Building Code,

Section 1632Structural Design Requirements – Earthquake Design – Lateral Force on Elements of Structures, Nonstructural Components and Equipment Supported by Structures

UL 73 Motor Operated AppliancesUL 471 Commercial Refrigerators and FreezersUL 698 Industrial Control Equipment for use in Hazardous LocationsUL 1450 Motor-Operated Air Compressors, Vacuum Pumps and Painting EquipmentUL 1740 Robots and Robotic EquipmentUL 1995 Heating and Cooling EquipmentUL 2011 Factory Automation Equipment

UL 3111-1 Electrical Measuring and Test EquipmentUL 3121-1 Process Control Equipment

Canadian Standards Title

CAN/CSA® 39 C22.1 Canadian Electrical Code, Part ICAN/CSA C22.2 No. 0 General Requirements – Canadian Electrical Code, Part II

CAN/CSA C22.2 No. 107.1 Commercial and Industrial Power SuppliesCAN/CSA C22.2 No. 234 Safety of Component Power SuppliesCAN/CSA C22.2 No. 950 Safety of Information Technology Equipment, including Electrical Business Equipment

CAN/CSA C22.2 No. 1010 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory Use

European Standards Title

EN 292-1 Safety of Machinery – Basic terminology and Technical principlesEN 292-2 Safety of Machinery – Technical Principles and SpecificationsEN 294 Safety of Machinery – Safety distance to prevent danger zones being reached by upper

limbsEN 418 Functional Aspects of Machinery Emergency Stop Equipment

EN 626-2 Elimination or reduction of risk to health from hazardous substances emitted by machinery, Part 2: Methodology leading to verification procedures

EN 811 Safety of Machinery – Safety distance to prevent zones being reached by lower limbsEN 953 Safety of machinery – Guards – General requirements for the design and construction of

fixed and moving guardsEN 954-1 Safety of machinery – Safety-related parts of control systems, Part 1: General principle for

designEN 1037 Safety of machinery – Prevention of unexpected start-upEN 1088 Safety of Machinery – Interlocking devices with and without guard locking

EN 1093-1 Evaluation of the emission of airborne hazardous substances, Part 1: Selection of test methods

EN 1093-9 Evaluation of the emission of airborne hazardous substances, Part 9: Pollutant concentration parameter – Room Method

EN 50178 Electronic equipment for use in power installationsEN 60204-1 Safety of Machinery – Electrical equipment of machines, Part 1

39 CSA trademark is owned by Canadian Standards Association.

SEMI S2-0818E © SEMI 1991, 2018 72

European Standards Title

EN 60529 Degree of Protection Provided by Enclosure (IP Codes)EN 60825-1 Safety of Laser Products, Part 1: Equipment Classification, Requirements and User’s

GuideEN 60950 Specifications for Safety of Information Technology Equipment, including Electrical

Business EquipmentEN 61010-1 Safety Requirements for Electrical Equipment for Measurement, Control and Laboratory

Japanese Standards Title

JIS C 0602 General Rules of Color Identification for Protective Conductor and Neutral ConductorJIS C 4610 Circuit breakers for equipmentJIS B 6015 Electrical Equipment of Machine ToolsJIS C 8371 Residual current operated circuit breakers

73 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 3 EMO REACH CONSIDERATIONSNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R3-1 IntroductionR3-1.1 Although SEMI S8 limits EMO button heights to 164 cm, it does not explicitly address the situation where a person must reach over, say, a work surface to reach the EMO button. The calculations shown below show one method of addressing this situation. Other issues, besides those shown below, must also be taken into account when locating EMO buttons; see SEMI S2 and SEMI S8.

Figure R3-1

SEMI S2-0818E © SEMI 1991, 2018 74

RELATED INFORMATION 4 SEISMIC PROTECTIONNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R4-1 Seismic Protection Checklist

Supporting Review Criteria for Seismic Protection of Related Components

If the answer to Questions A.1 or A.2 is ‘No,’ or the answer to any other of these questions in the checklist is ‘Yes,’ then a detailed analysis may need to be performed by a structural or mechanical engineer.A. Equipment Anchorage1. Have lateral force and overturning calculations been performed (see example)?

Yes No Comments:

2. Are all modules fastened at a minimum of four points and can the fasteners support the forces identified in question 1 above? Yes No Comments:

3. Is it possible that there could be excessive seismic anchor movements that could result in relative displacements between points of support or attachment of the components (e.g., between vessels, pipe supports, main headers, etc.)? Yes No Comments:

4. Is there inadequate horizontal support? Yes No Comments:

5. Is there inadequate vertical supports and/or insufficient lateral restraints? Yes No Comments:

6. Are support fasteners inappropriately secured? Yes No Comments:

7. Is there inadequate anchorage of attached equipment? Yes No Comments:

186:[187:] One way of judging whether supports, fasteners, or anchorages are ‘inadequate’ or ‘inappropriately secured’ is to determine whether their stress levels under seismic loading stay below the allowable stress levels set by building code. Such allowable stress levels are typically a fraction <1 of the yield strength.

B. Equipment Assembly, Installation and Operation1. Are the materials of construction of the components susceptible to seismic damage?

Yes No Comments:

2. Are there significant cyclic operational loading conditions that may substantially reduce system fatigue life? Yes No Comments:

75 SEMI S2-0818E © SEMI 1991, 2018

3. Are there any threaded connections, flange joints, or special fittings? Yes No Comments:

4. If answer to Question 4 is ‘Yes,’ are these connections, joints, or special fittings in high stress locations? Yes No Comments:

5. Are there short or rigid spans that cannot accommodate the relative displacement of the supports (e.g., piping spanning between two structural systems)? Is hazardous gas piping provided with a ‘pigtail’ (i.e., spiral) or bent 3 times (z, y, and z direction) to absorb 3-dimensional displacements? Yes No Comments:

6. Are there large, unsupported masses (e.g., valves) attached to components? Yes No Comments:

7. Are there any welded attachments to thin wall components? Yes No Comments:

8. Could any sensitive equipment (e.g., control valves) be affected? Yes No Comments:

C. Seismic Interactions1. Are there any points where seismically induced interaction with other elements, structures, systems, or

components could damage the components (e.g., impact, falling objects, etc.)? Yes No Comments:

2. Could there be displacements from inertial effects? Yes No Comments:

R4-2 Derivation of § 19 , Seismic Force GuidelinesR4-2.1 The horizontal forces (Fp) of 94% and 63% of the equipment weight (Wp), found in §§ 19.2.1 and 19.2.2 , were based on following assumptions for factors in the design lateral force formula 32-2 in §  1632.2 of the 1997 Uniform Building Code (UBC):

ap = 1.0 (i.e., treat the equipment as a rigid structure) Ca = 0.53 (i.e., seismic zone 4, soil profile type SD, and site 5 km from a seismic source type A) Ip = 1.0 and 1.5 for non-HPM and HPM equipment, respectively (see Table 16-K) hx/hr = 0.5 (i.e., equipment attached at point halfway between grade elevation and roof elevation) Rp = 1.5 (i.e., shallow anchor bolts), not from Table 16-K but § 1632.2 explanation of Rp.

FP=a pCa I p

R p (1+3( hx

hr ))W p (R4-1)

R4-2.2 Assumptions Used for Above Derivation

R4-2.2.1 Regarding the selection of 1.0 as the value for ap – Table 16-O of the 1997 UBC assigns values of ap

depending on the type of building component under consideration. Line 3-B is for electrical, mechanical and plumbing equipment which generally describes semiconductor manufacturing equipment, as is assigned an a p value of 1.0. Line 3-C is the only line in the equipment group (3) that is assigned an ap value greater than 1.0. Since this 3-C line is applicable to “Any flexible equipment...” and in structural terms, typical semiconductor equipment was considered to be rigid rather than flexible in structural terms. Per 1997 UBC § 1634.3, rigid structures have a period less than 0.06 seconds (i.e., a natural frequency greater than 16.67 Hz).

SEMI S2-0818E © SEMI 1991, 2018 76

R4-2.2.2 Regarding the selection of 0.53 as the value for Ca – Table 16-Q of the 1997 UBC gives values for Ca

based on Soil Profile Type (selected as SD, Stiff Soil Profile, see Table 16-J), and Seismic Zone Factor (selected as 0.4 - determined from Seismic Zone 4 per the map in Figure 16-2 and Table 16-I). From those values, Table 16-Q indicates the value of Ca to be 0.44Na, where Na, the Near Source Factor, is 1.2, per Table 16-S based on a Seismic Source Type selected as A (“Faults that are capable of producing large magnitude events and that have a high rate of seismic activity” from Table 16-U) and a distance to the seismic source, selected as 5 km. Thus C a = 0.44 × 1.2 = 0.53.

R4-2.2.3 Because typical semiconductor equipment is considered rigid, a frequency response analysis was not considered to be necessary.

R4-2.2.4 Assuming when the ground and building is accelerating downward, the lessened equipment weight load is symmetrical to the additional weight load when the ground is accelerating upward, the worst case (i.e., the least) amount of equipment weight available to oppose an overturning force would, be 67% of W and 74% of W for HPM and non-HPM equipment, respectively.

187:[188:] In 2016 the S2 Seismic task force reviewed the worst case conditions for opposing the overturning force on equipment and decided to assume, that the vertical and horizontal seismic waves will be at their maximum, worst case values at the same time, and to provide values for the HPM and non-HPM cases separately.

R4-3 Examples of Seismic Design Loads Based on Standards and Codes Applicable for Some of the Known Semiconductor Manufacturing Locations188:[189:] The examples in §§ R4-3.1, R4-3.2, and R4-3.3 are only rough approximation of the calculations and analysis required. Refer to the specific standards and codes for a complete understanding of how to apply them.

189:[190:] It was the intention of the Japan Seismic Protection TF to include values of seismic protection design loads and supporting formula applicable in Europe, but they were unable to identify adequate references for this revision.

R4-3.1 United States using American Society of Civil Engineers® 40 (ASCE® 41) 7-10

R4-3.1.1 The horizontal seismic design force, Fp, is derived from the following equations and variables (see ASCE 7-10 Equations 13.3-1, 13.3-2, and 13.3-3). The semiconductor manufacturing equipment is considered a nonstructural building component:

FP=0.4 aP SDSW P

( RP

I P )(1+2 z

h ) (R4-2)

Fp is not required to be taken as greater than:

FP=1.6× SDS × IP× W P (R4-3)

and Fp should not be taken as less than:

FP=0.3× S DS × I P× W P (R4-4)

where:

SDS = design, 5 percent damped, spectral response acceleration parameter at short periods (see ASCE7-10 § 11.4.4).

SDS is given by (see ASCE 7-10 Equations 11.4-1 and 11.4-3)

SDS = 2/3 × Fa × SS

Ss shall be in accordance with 11.4.1, but need not be taken larger than 1.5, according to ASCE 7-10 § 12.14.8.1.

Therefore, the maximum value of SDS becomes ‘SDS = 2/3 × 1 × 1.5 = 1’ from ASCE 7-10 Table 11.4-1.

‘SDS = 1’ is considered to be the most conservative value to be applied for equipment installed in the U.S.

40 American Society of Civil Engineers trademark is owned by American Society of Civil Engineers.41 ASCE trademark is owned by American Society of Civil Engineers.

77 SEMI S2-0818E © SEMI 1991, 2018

ap = component amplification factor. Manufacturing and process equipment is assigned a value of 1.0 (see ASCE7-10 Table 13.6-1).

RP = component response modification factor. Manufacturing and process equipment is assigned a value of 2.5 (see ASCE7-10 Table 13.6-1).

IP = component importance factor. Generally speaking, equipment that contains toxic or explosive substances is assigned a value of 1.5, and a value of 1.0 otherwise (see ASCE 7-10 § 13.1.3).

WP = operating weight of the component.

z = height in structure at point of attachment of component with respect to the base.

h = average roof height of structure with respect to the base.

R4-3.1.1.1 Generally process equipment is considered rigid. For flexible equipment ap would be assigned a value of 2.5 see ASCE7-10 Table 13.6-1). According to ASCE 7-10 § 11.2, a flexible component is a nonstructural component having a fundamental period greater than 0.06 s, and a rigid component is a nonstructural component having a fundamental period less than or equal to 0.06 s.

R4-3.1.1.2 The vertical seismic design force is given in the text of ASCE7-10 § 13.3.1 and should be considered a concurrent force = ±0.2 SDS WP.

R4-3.2 Taiwan Using the Taiwan Building Code (TBC)

R4-3.2.1 The horizontal seismic design force, Fph is derived from the following equations and variables (see equations 4-1a, 4-1b, and 4-1c). The semiconductor manufacturing equipment is considered a nonstructural building component:

F ph=0.4 SDS I p

ap

Rpa∙(1+2 hx /hn)×W p (R4-5)

where Fph is not required to be taken as greater than:

F ph=1.6 ×S DS × I P× W P (R4-6)

and Fph should not be taken as less than:

F ph=0.3× SDS × I P× W P (R4-7)

where:

SDS = design, 5 percent damped, spectral response acceleration parameter at short periods.

ap = component amplification factor. General process equipment is assigned a value of 1.0 (see TBC Table 4-2).

Rpa = allowable seismic response reduction factor.

Ip = component importance factor (1.5 for life safety related equipment or equipment with toxic or flammable materials; 1.0 for others).

WP = component operating weight.

hx = distance between the foundation and the floor on which the component is located.

hn = distance between the foundation and the roof.

R4-3.2.2 SDS is given by:

SDS=Fa× SSD (R4-8)

where:

SSD = design horizontal response acceleration coefficients for site with short natural period from TBC Table 2-1.

Values include: Hsinchu generally 0.6 to 0.8; Hsinchu science park 0.7 to 0.8; Taichung 0.7 to 0.8; Tainan 0.7 to 0.8.

SEMI S2-0818E © SEMI 1991, 2018 78

Fa = amplification factor of site response acceleration spectrum from TBC Table 2-2(a). Values range from 1.0 to 1.2 depending on the site soil profile category (firm, normal, or soft) and the value of SS

D .

R4-3.2.3 Rpa is given by:

Rpa=1+Rp−1

1.5

¿1+(2.5−1)/1.5=2 (R4-9)

where Rp for general process equipment is assigned a value of 2.5 (see TBC Table 4-2).

R4-3.2.4 The vertical seismic force, Fpv is given by:

F pv=12

F ph (R4-10)

for general sites or the Taipei Basin, or:

F pv=23

F ph (R4-11)

for sites near fault zones (e.g., 2 km or less).

R4-3.3 Japan Using “Seismic Design and Construction Guideline for Building Equipment” — In Japan, there are several guidelines for non-structural elements of buildings (also called as ‘building equipment’). One of the more commonly used guidelines is the “Seismic Design and Construction Guideline for Building Equipment” published by Building Center of Japan (BCJ). It conforms to the Building Standard Law of Japan and has been adopted as a jurisdictional requirement for building construction. The sufficiency of the criteria in the Guideline has been field-proven in several large earthquakes in Japan of greater than ‘6-Lower’ intensity per the Japan Meteorological Agency (JMA) seismic intensity scale. This example uses the so-called “Local Earthquake Intensity Method” from the Guideline. The guideline is titled “建築設備耐震設計・施工指針” in Japanese. There is no official English translation available. The translation “Seismic Design and Construction Guideline for Building Equipment” and other translation of terms and descriptions were provided by the Japan Seismic Protection TF. They are intended to be reasonably understandable and adequate.

R4-3.3.1 The design horizontal seismic force FH (acting on the equipment center of gravity) is given by:

FH=K H × W (R4-12)

where:

KH = design horizontal seismic intensity.

W = equipment operational weight (in kilonewton – kN).

When the design vertical seismic force Fv need to be considered:

FV=KV × W (R4-13)

KV =12

KH (R4-14)

where:

KV = the design vertical seismic intensity.

As general building structure other than seismically isolated structure is required of dynamic analysis, Design horizontal seismic intensity (KH) is given by:

K H=Z × K S (R4-15)

where:

79 SEMI S2-0818E © SEMI 1991, 2018

KS =standard design seismic intensity.

Z = regional coefficient (see R4-3.3.2.1 Figure R4-2). For most of semiconductor manufacturing locations in Japan this value is 1.0.

R4-3.3.2 KS is selected based on the location of the equipment in the building, and the desired Class of seismic resistance (see Table RR4-3.3.2.1.1 Table R4-1 ). Generally speaking, users ask semiconductor manufacturing equipment to be Class A. There are also particular values applied when the equipment is a water tank in the basement or on the first floor.

Table R4-1 Standard Design Seismic Intensity (KS)

Floor Location#1Seismic

Resistance Class S#2

Seismic Resistance Class A#2

Seismic Resistance Class B#2

Illustration of Floor Locations#1

Upper Floors,Roof or Penthouse 2.0 1.5 1.0

Middle Floors 1.5 1.0 0.6

First Floor or Basement 1.0 (1.5)#3 0.6 (1.0)#3 0.4 (0.6)#3

#1 Floor Locations‘Upper Floors’ means:・The top floor of a two to six story building.・The top floor and the next to the top floor of a seven to nine story building.‘Middle Floors’ means:・All the floors except for the Basement, First Floor and Upper Floors.#2 Seismic Resistance Class (See Table R4-2 for the meaning of each class) is selected based on the followings:・The Seismic Resistance Class is to be selected for equipment considering its function during or after severe earthquakes.・The Seismic Resistance Class for equipment on vibration isolation devices is to be selected as Class A or Class S.#3 The values within parentheses apply to water tanks.

Table R4-2 Meaning of Seismic Resistance Class

Seismic Resistance Class Meaning

S Human safety is assured and secondary damage prevented after a major earthquake. All functions are maintained securely without major repairs.

A Human safety is assured and secondary damage prevented after a major earthquake. Important functions are maintained securely without major repairs.

B Human safety is assured and secondary damage prevented after a major earthquake.

SEMI S2-0818E © SEMI 1991, 2018 80

PenthouseUpper Floors

Middle Floors

First Floor

Basement

Figure R4-2 Map of Regional Coefficients, Z, in Japan

R4-4 Example Calculation of Lateral Force and Vertical Force on Equipment Anchor BoltsR4-4.1 The following calculations are not a complete seismic analysis. A complete analysis include such things as: stress distribution through a multiple-fastener connection; prying action; bearing stress; simultaneous combined stresses on the fasteners; and a review of weld geometry. A complete seismic analysis should be done by a qualified engineer.

R4-4.2 This is a generic example. It assumes a box shaped piece of equipment anchored by N bolts distributed evenly on two opposite sides of the box, N bolts on each side.

R4-4.3 The maximum anticipated horizontal force (FH) and vertical force (FV) acting simultaneously on the center of gravity of the equipment will come from the selected regional requirement or the minimum values given in §  19.2.

190:[191:] The force values used in the following calculation are the minimum values for equipment containing HPMs given in § 19.2 .

R4-4.4 Figures R4-2 and R4-3 illustrate the key factors of the calculation. Table R4-3 explains the key variables and provides example values for the calculation.

191:[192:] A similar calculation is provided in the 1991 American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) handbook, Chapter 49 “Seismic Restraint Design”.

192:[193:] An explanation of why the effective weight of the equipment can be less than the weight when the equipment is in motion during a seismic event can be found by researching, for example, ‘elevator physics’.

81 SEMI S2-0818E © SEMI 1991, 2018

Table R4-1 Key Variables and Examples

Variable Notes Value for this Example

W The maximum normal operating weight of the equipment. 49,000 Newtons#1

(5000 kg force)FH The maximum anticipated seismic horizontal force acting on the equipment. 0.94W (HPM)FV The vertical seismic force by which the weight is reduced to determine effective

weight used for overturning calculations.0.33W (HPM)

WE The effective weight of the equipment accounting for the vertical seismic force (W – Fv).

0.67W (HPM)

G The center of gravity of the equipment. As indicatedZ The height of the center of gravity. 2 metersR The tensile force on an anchor bolt. to be calculatedr The lateral force on an anchor bolt. to be calculatedN The total number of anchor bolts. 6n The total number of anchor bolts on one side of the equipment. 3X The distance between the two rows of n anchor bolts (= L + L’). 1 meterL The shortest distance from a row of anchor bolts to the horizontal position of G. 0.4 meters

#1 Earth’s surface gravity exerts a force of 9.8 Newton on 1 kilogram of mass.

#1 Dashed lines show the forces which are summed to give WE.Figure R4-2

Illustration of the Key Factors and The Seismic Motions

SEMI S2-0818E © SEMI 1991, 2018 82

X

LSide AL’

Side B

Figure R4-3 Illustration of the Key Factors

R4-4.5 FH may vary depending on whether the equipment contains HPMs or not, and is usually expressed as a portion of the equipment weight. For this example it is taken as 0.94W (The minimum anticipated value from § 19.2 for equipment containing HPMs).

R4-4.6 FV is not necessarily the maximum vertical force that could act on the equipment because of the assumption in ¶ RR4-2.2.4 . This value is also usually expressed as a portion of the equipment weight. For this example it is taken as 0.33W.

R4-4.7 This example uses the length L rather than L’ to calculate the moment due to the effect weight of the equipment (which opposes the overturning moment), because it results in the worst case (smaller) value for the moment.

R4-5 Calculation of Overturning ForceR4-5.1 For the equipment not to begin overturning, the sum of the angular moments (torques) around the line through the bolts on Side B must be zero (taking clockwise as the positive direction):

∑ M=(FH × Z ¿−(R × X × n ) - ( W E × L )=0 (R4-16)

R4-5.2 For the example configuration, the worst case tensile force (R) on a single bolt (on side A) is given by:

R=(F¿¿ H × Z)−(W E × L)

X ×n¿ (R4-17)

Using the example values gives:

R= (0.94 × 49,000 N ×2m )−(0.67 × 49,000 N × 0.4 m )1m ×3

=0.54 × 49,000 N=26,460 Newtons (R4-

18)

R4-5.3 If the worst case tensile stress on the anchor bolts exceeds the tensile strength of the bolts or the strength of the bolt-to-floor bond, then the equipment might overturn.

R4-5.4 If there are no anchor bolts installed, the equipment will begin to overturn if:

( FH × Z ¿> (W E × L ) (R4-19)

but whether the equipment completely overturns or not will depend on the duration and simultaneity of the worst case vertical force and the worst case horizontal force.

83 SEMI S2-0818E © SEMI 1991, 2018

R4-6 Calculation of Lateral ForceR4-6.1 The lateral force on one bolt (r) is derived from the maximum anticipated horizontal force acting on the equipment’s center of gravity as follows:

r=FH /N (R4-20)

Using the example values gives:

r=0.94 W /6=7,677 Newtons (R4-21)

R4-6.2 The lateral force acts as shear on the floor anchor fasteners and shear or tensile loading on the equipment anchor fasteners depending upon their orientation.

SEMI S2-0818E © SEMI 1991, 2018 84

RELATED INFORMATION 5 CONTINUOUS HAZARDOUS GAS DETECTIONNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R5-1 GeneralR5-1.1 Scope — This Related Information provides a list of gases for which continuous monitoring is recommended, and another list of gases for which continuous monitoring may be recommended depending on variables listed below. The list is not intended to be exhaustive (gases that do not appear on the list may need to be continuously monitored).

R5-1.2 Intent — The purpose of this Related Information is to provide equipment manufacturers with an indication as to what gases are currently continuously monitored by device manufacturers, as guidance for when it may be appropriate to provide an interface (see also § 23 ).

R5-1.3 The following variables should be taken into consideration when determining the necessity for continuous monitoring:

Chemical toxicity,

Warning property/OEL ratio,

Delivery pressure,

Lower Flammable Limit (LFL),

Flow rate of potential leak,

Engineering controls in place, and

Concentration.

Monitoring Recommended Monitoring May Be Recommended

ammoniaarsine

boron trifluoridebromine

carbon dioxidecarbon monoxide

carbon tetrabromidechlorinediborane

dichlorosilanedisilanefluorinegermane

germanium tetrafluorideflammable mixtures containing hydrogen

hydrogen bromidehydrogen chloridehydrogen fluoridehydrogen selenide

85 SEMI S2-0818E © SEMI 1991, 2018

Monitoring Recommended Monitoring May Be Recommended

hydrogen sulfidemethane

methyl chloridemethyl fluoride

nitric oxidenitrogen dioxide

nitrous oxidenitrogen trifluoride

ozonephosphine

silanesilicon tetrachloridesilicon tetrafluoride

sulfur dioxidetrichlorosilane

tungsten hexafluoride

SEMI S2-0818E © SEMI 1991, 2018 86

RELATED INFORMATION 6 DOCUMENTATION OF IONIZING RADIATION (§ 24 AND APPENDIX APPENDIX 2) INCLUDING RATIONALE FOR CHANGESNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R6-1 International Background InformationR6-1.1 The International Atomic Energy Agency (IAEA)

Mailing address:

P.O. Box 100Wagramerstrasse 5 A-1400, Vienna, Austria Telephone: (+43-1) 2060-0; Facsimile: (+43-1) 20607: E-mail: Official.Mail@iaea.org

R6-1.2 Basic approaches to radiation protection are consistent all over the world. The International Commission on Radiation Protection (ICRP) recommends that any exposure above the natural background radiation should be kept as low as reasonably achievable, but below the individual dose limits. The total individual dose limit for radiation workers over 5 years is 100 mSv, and for members of the general public, is 1 mSv per year. These dose limits have been established based on a prudent approach by assuming that there is no threshold dose below which there would be no effect. This hypothesis proposes that any additional dose will cause a proportional increase in the chance of a health effect. This relationship has not yet been established in the low dose range where the dose limits have been set.

R6-1.3 The ICRP and the IAEA recommend the individual dose must be kept as low as reasonably achievable and consideration must be given to the presence of other sources that may cause simultaneous radiation exposure to the same group of the public. Also, allowance for future sources or practices must be kept in mind so that the total dose received by an individual member of the public does not exceed the dose limit.

R6-2 How Does This Apply to the Semiconductor Industry?R6-2.1 A person who can potentially be exposed to ionizing radiation during the normal course of business in excess of the annual limit for the general public should be considered a radiation worker. A radiation worker is trained to recognize and protect him or herself from the hazards of ionizing radiation. They may require exposure monitoring to determine compliance with local radiation regulations. Radiation workers are covered by a radiation safety program. A radiation safety program is an administrative control. Engineering controls minimize the need for spending resources in a large scale radiation program.

R6-2.2 The exposure limit for the radiation worker is 20 millisievert (2000 millirem) per year. Based on a 40 hour/week, 50 week/working year basis, the allowable ionizing radiation emissions are 10 microsieverts/hour (1.0 millirem/hour). This exposure rate should be evaluated as an emission rate from any accessible surface of the equipment (the closest approach to the surface that the radiation is penetrating).

R6-2.3 Maintenance technicians for radiation machines should be participants in the radiation safety program as radiation workers. The equipment should be designed to allow maintenance technicians access to areas that do not exceed 10 microsieverts/hour.

R6-2.4 Service technicians for radiation machines should be participants in their employer’s radiation safety program as radiation workers. The equipment should be designed to allow service technicians access to areas that exceed the 10 microsievert per hour level when operating, but not while the radiation is present.

R6-2.5 The person operating radiation producing equipment (Operator) should not be considered a radiation worker. The emission limit for the operator accessible areas is recommended to be 20% of the occupational limit. The maximum allowable ionizing radiation emissions for operator accessible areas are recommended to be

87 SEMI S2-0818E © SEMI 1991, 2018

2 microsieverts/hour (0.2 millirem/hour). This exposure rate should be evaluated as an emission rate from any surface foreseeably accessible by an operator of the equipment, and should be measured as an instantaneous rate.

R6-3 DefinitionsR6-3.1 accessible — a significant part of the whole body, head, or eyes.

R6-3.2 bremsstrahlung — is radiation produced by slowing of charged particles. The term means ‘braking radiation.’

193:[194:] During design of shielding, the properties of the radiation should be considered as well as the properties of the shielding materials. Bremsstrahlung production should be minimized. Some shielding materials are considered hazardous materials. These hazardous properties should be considered and identified.

R6-3.3 radiation machine — means any device capable of producing ionizing radiation except those devices with radioactive material as the only source of radiation.

R6-3.4 radiation producing machine — is a radiation machine that produces ionizing radiation as a by-product of the process it uses (e.g., ion implanter or scanning electron microscope).

R6-3.5 radiation worker — ‘worker’ means an individual engaged in radiation related work under a license or certificate of registration issued by the Agency and controlled by a licensee or registrant, but does not include the licensee or registrant.

R6-3.6 radioactive material — means any material (solid, liquid, or gas) that emits ionizing radiation spontaneously.

R6-3.7 X-ray machine — is a radiation machine that generates X-rays as a primary function of the equipment. This category of radiation machine has a specific limit due to the existence of performance standards against which the equipment is evaluated. The equipment must be below this limit to be sold in some parts of the world.

R6-3.8 X-rays — are produced with electricity and therefore can be turned off. X-rays seem to be the most prevalent radiation type in semiconductor manufacturing equipment. They are produced when charged particles are slowed or stopped. This slowing results in ‘bremsstrahlung.’ The majority of the equipment does not intentionally produce X-rays. This energy is a by-product of the process.

R6-4 Radioactive MaterialsR6-4.1 Gamma radiation is a by-product of atomic transformations (decay) and is a release of energy from the nucleus. This radiation energy must be shielded since there is no off switch.

R6-4.2 Radioactive Materials are controlled by licensing. There are quantities of certain radioactive materials that are exempt from regulation. These sources should be identified.

R6-4.3 External radiation hazards from radioactive materials include gamma rays. These are controlled and evaluated much like the X-rays.

R6-4.4 Internal radiation hazards from radioactive materials include Alpha and Beta particles. Radioactive materials ingested or inhaled can be metabolized or damage surrounding tissue. Allowable levels of airborne radioactivity and radionuclide intakes are specified in regulations. The objective is still to maintain all exposure to ionizing radiation (internal and external) as low as reasonably achievable, but always less than the allowable regulatory limits.

SEMI S2-0818E © SEMI 1991, 2018 88

RELATED INFORMATION 7 DOCUMENTATION OF NON-IONIZING RADIATION (§ 25 AND APPENDIX APPENDIX 3) INCLUDING RATIONALE FOR CHANGESNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on December 24, 2011.

R7-1 Rationale for Revisions Made in 2011 and 2012R7-1.1 General Goals of the Revision

R7-1.1.1 The primary purpose of this revision was to update the published criteria to reflect:

revisions of the referenced standards since initial publication,

standards and regulatory limits published since the initial publication of this criteria such as the EU Worker Protection directives, and

lessons learned and problems found in using the published criteria.

R7-1.1.2 With bay and chase style facilities becoming less common and open ballroom style facilities becoming more common, the distinction between potential operator and maintenance/service exposures became much harder to define and justify. Therefore this revision defines a single emission limit value or function.

R7-1.2 Static Magnetic Emissions — The criteria were revised upward and measurement technique clarified as the task force could find no referenced standard to justify keeping the values at the existing published level. The levels were set to the EU WP directive action level as these are significantly more stringent than any other published standard we could find. Since the higher allowable levels made the possibility that the 30 mT tool movement concern to be more likely, the labeling requirement for this concern was clarified/expanded.

R7-1.3 Sub Radiofrequency Emissions

R7-1.3.1 The power frequency criteria that were provided as deviations from the rest of the sub radiofrequency criteria in the original criteria were eliminated as the agency that recommended them (International Commission on Non-Ionizing Radiation Protection [ICNIRP]) no longer includes the lower recommended values, and no other limits (e.g., ACGIH, EU Worker Protection directives) have adopted these lower limits.

R7-1.3.2 The electric (E) field criteria were left the same as previously published (20% of the ACGIH values).

R7-1.3.3 The magnetic (H) field criteria were reduced above 682.5 Hz in order to align with the EU Worker Protection Directive action levels. Below 682.5 Hz, the values were left at the previously published values (20% of the ACGIH values).

R7-1.4 Induced and Contact Current

R7-1.4.1 The primary changes were to reduce to a single criteria for both operators and maintainers and to clarify the criteria as the previous criteria had some aspects that allowed differing interpretations.

R7-1.4.2 The induced current criteria were set at the previous maintenance and service criteria, which is 20% of the IEEE C95.1 controlled environment value.

R7-1.4.3 The contact current criteria were set at the previously published operators level as the applicable criteria have been decreasing in all of the referenced standards. The new criteria are between 50% of the IEEE C95.1-2005 general population values and 25% of the 2010 ACGIH values.

R7-1.5 Radio Frequency Electric (E) and Magnetic (H) Field and Power Density (S) Emissions

R7-1.5.1 In addition to the general drivers for the revision for this effort, RF frequency (3 kHz to 300 GHz) criteria had another driver, providing criteria that will not become invalid by a revision of the referenced standard (as was done by the 2005 revision of IEEE C95.1 that moved the criteria to different tables than those specified in the previous SEMI S2 criteria).

89 SEMI S2-0818E © SEMI 1991, 2018

R7-1.5.2 The electric (E) field criteria are derived from the 1999 IEEE C95.1 values as the 2005 revision deleted criteria from 3 to 100 kHz. The criteria are the same as the previously published Maintenance and Service criteria (20% of the controlled environment criteria).

R7-1.5.3 The magnetic (H) field criteria were significantly modified (lowered) to align with the EU worker protection directive for EM fields (2004/40/EC) (which hadn’t been published when the SEMI S2 criteria were originally written) up to 20.375 MHz. Above 20.375 MHz, the criteria align with the previously published SEMI S2 Maintenance and Service criteria (20% of the IEEE C95.1 controlled environment criteria).

R7-1.5.4 The power density (S) criteria were modified as they are based upon the IEEE C95.1 uncontrolled environment or general population limit which was significantly reduced with the 2005 revision for frequencies below 122.22 GHz. Above 122.22 GHz, the values remain at the previously published SEMI S2 Maintenance and Service criteria (20% of the IEEE C95.1 controlled environment criteria).

R7-1.6 Optical Radiation Emissions

R7-1.6.1 This section was revised to:

a) define the hazards of optical energy more clearly, as previous criteria seemed to focus in UV concerns,

b) provide additional measurement guidance on the different criteria,

c) align with revisions and additions to the various referenced criteria, and

d) delete the 20% multiplier of the external referenced limits.

R7-1.6.2 The new criteria allow for some flexibility on measurement distance and time of exposure when it can be justified by the foreseen exposure scenarios and is adequately communicated.

R7-2 Rationale for Initial Publication of CriteriaR7-2.1 The user of this table is responsible for obtaining the current revision of the standards cited for occupational exposure limits (OEL).

R7-2.2 The emission values in Appendix APPENDIX 3 that are not to be exceeded were chosen based on a review of all known international standards as well as a consideration for best available control technology (i.e., lowest values currently achievable for each radiation type). Where a general public limit existed, 20% of this value was selected. Where there was no public limit, the value selected is generally 20% of the OEL value (instantaneous field strength measurement peak). The latter case would have the occupational and general public levels the same. Where there was an occupational exposure limit specified in a standard, the maintenance emission limit was set at 20% of this level.

R7-2.3 Most health standards differentiate between ‘occupational’ and ‘general public’ exposure criteria. IEEE C95.1 differentiates between ‘controlled access’ and ‘uncontrolled access’ exposures. According to IEEE C95.1 ‘controlled access’ environments are those where “locations where there is exposure that may be incurred by persons who are aware of the potential for exposure as a concomitant of employment, by other cognizant persons, or as the incidental result of transient passage through areas where analysis shows the exposure levels may be above those shown in Table 2 but do not exceed those of Table 1, and where the induced currents may exceed the values in Table 2, Part B, but do not exceed the values of Table 1, Part B.” According to IEEE C95.1, ‘uncontrolled access’ environments are “locations where there is the exposure of individuals who have no knowledge or control of their exposure. The exposure may occur in living quarters or workplaces where there are no expectations that the exposure levels may exceed those shown in Table 2 and where induced currents do not exceed those in Table 2, Part B.” Task force members advise that IEEE C95.1 ‘controlled access’ and other ‘occupational exposure’ standards should be applied to personnel performing maintenance and service of equipment and that ‘uncontrolled access’ or other ‘general public’ standards should be applied to equipment operators during routine work and to other locations. These IEEE definitions are particularly relevant to broadcast facilities as well as normal industrial environments such as fabs. Task force members recommend that uncontrolled access limits be applied to fetal exposure.

R7-2.4 As with the rationale in the Ionizing section, the operator is considered a member of the general public or to be in an uncontrolled area. Maintenance or service technicians should be trained to know how to control the hazardous energy and protect themselves from the hazard and its adverse effects.

SEMI S2-0818E © SEMI 1991, 2018 90

R7-2.5 References

R7-2.5.1 1996 TLVs and BEIs Threshold Limit Values for Chemical Substances and Physical Agents Biological Exposure Indices, ACGIH, Cincinnati, OH.

R7-2.5.2 Guidelines on Limits of Exposure to Broad-Band Incoherent Optical Radiation (0.38 to 3 M), Health Physics Vol. 73, No. 3 (September 1997): pp.539–554.

R7-2.5.3 ICNIRP 1994 “Guidelines on Limits of Exposure to Static Magnetic Fields.” Health Physics Vol 66 (1) (January 1994): pp. 100–106.

R7-2.5.4 IEEE C95.1-1991 — Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz

R7-2.5.5 Interim Guidelines on the Limits of Exposure to 50/60 Hz Electric and Magnetic Fields, IRPA/ICNIRP Guidelines, Health Physics Vol. 58, No. 1(January 1990): pp. 113–122.

91 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 8 LASER EQUIPMENT SAFETY FEATURESNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on April 22, 2004.

Table R8-1 Equipment Safety Features Reference Table

Reference Number

Equipment Safety Features

(not an inclusive list)#4

USA21 CFR

1040.10#1

EuropeIEC 60825-1#2

JapanJIS C 6802#3

Examples

1 Protective Housing (f)(1) 4.2 4.2.1 Aluminum or steel enclosures, windows that provide adequate attenuation, optical fibers or beam tubes.

2 Safety Interlocks (f)(2) 4.3 4.2.2 See Interlock Section of SEMI S2.3 Remote Interlock

Connector(f)(3) 4.4 4.2.3 Usually a 12–24 volt set of contacts

available to the user to integrate additional room control measures.

4 Key Control (f)(4) 4.5 4.2.4 A key that is not removable in the operations mode.

5 Laser Radiation Emission Warning

(f)(5) 4.6 4.2.5 A light or indicator that warns the user of the emission through the aperture.

6 Beam Attenuator (f)(6) 4.7 4.2.6 Shutters, beam blocks or water-cooled beam dumps.

7 Location of Controls (f)(7) 4.8 4.2.78 Viewing Optics (f)(8) 4.9 4.2.8 Must block all hazardous wavelengths to

acceptable levels.9 Scanning Safeguard (f)(9) 4.10 4.2.9 Shuts down if the scanning mechanism

(such as a rotating mirror or galvanometer) fails.

10 Manual Reset Mechanism

(f)(10) 4.3.1 4.2.2(c) A button or circuit that must be energized before the equipment resumes its functions.

11 Class Designation & Hazard Alert Labels

(g)(1)– (g)(4) 5.1–5.6,5.8–5.11

4.3 Identify which standard was used for each hazard classification.

12 Aperture Label (g)(5) 5.7 4.3.7 Identify the aperture.13 Positioning of Labels (g)(9) 5.1 4.3.1 Conspicuous, but size is not specified.14 User Information (h)(1) 6.1 4.4.1 SOPs, instruction manuals15 Service Information (h)(2) 6.2 4.4.2 Accessible laser radiation levels during

Service.16 Measurements (e) 9 3.417 Classification (c) 8 3.3.318 Certification

Information21 CFR

19 Certification Label 1010.220 Identification Label 1010.3

#1 The US FDA/CDRH makes 21 CFR 1040.10 available, so the latest version should be used. The version used to update this table was dated April 1, 2003.#2 The IEC laser products standard used to update this table was 60825-1 © IEC: 1993+A1:1997+A2:2001(E).

SEMI S2-0818E © SEMI 1991, 2018 92

#3 The Japanese Standards Association® 42 does not offer the current version of JIS C 6802 in English. However, the current version should be used, and the Japanese version is the official version. The sections referenced in the table above are from the 1991 English version of JIS C 6802.#4 This requirement applies only to certain classes of lasers.

194:[195:] Both the IEC and the US FDA/CDRH have published guides to assist manufacturers with laser product conformance.

195:[196:] The FDA/CDRH has published Laser Notice 50. This laser notice provides guidance to manufacturers relating to the FDA/CDRH acceptance of laser products conforming to the IEC 60825-1 standard. There are conditions and additional requirements, so manufacturers should obtain this laser notice for the details.

R8-1 Referenced DocumentsR8-1.1 IEC Standard43

IEC 60825-1 — Safety of Laser Products, Part 1: Equipment Classification, Requirements, and User’s Guide

R8-1.2 US Code of Federal Regulations44

21 CFR Parts 1000–1050 — Food and Drug Administration/Center for Devices and Radiological Health (FDA/CDRH), Performance Standards for Electronic Products, Title 21 Code of Federal Regulations, Parts 1000–1050

42 Japanese Standards Association trademark is owned by Japanese Standards Association.43 International Electrotechnical Commission, 3 rue de Varembé, Case Postale 131, CH-1211 Geneva 20, Switzerland; Telephone: +41.22.919.02.11, Fax: +41.22.919.03.00, http://www.iec.ch 44 United States Food and Drug Administration/ Center for Devices and Radiological Health (FDA/CDRH). Available from FDA/CDRH http:// www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm

93 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 9 LASER CERTIFICATION REQUIREMENTS BY REGION OF USENOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

Table R9-1 Regional Laser Standards

USA Europe Japan Pacific Rim

Classification Standards 21 CFR 1040.10 EN 60825-1 JIS C 6802 IEC 60825-1Certification Standards 21 CFR 1000-1010 TBD TBD TBD

R9-2 USAR9-2.1 Food and Drug Administration (FDA), Center for Devices and Radiological Health (CDRH)

R9-2.1.1 Laser products must comply with the performance requirements of Title 21 of the Code of Federal Regulations Part 1040.10 (21 CFR 1040.10). Manufacturers (including modifiers) of laser products must certify to the FDA/CDRH in writing that the product complies with the requirements of 21 CFR SubChapter J.

R9-2.1.2 The reporting requirements are detailed in 21 CFR 1000–1010. Product report forms and the guidance document are available from the CDRH. These documents should soon be available from the CDRH Web server at: http://www.fda.gov/cdrh.

R9-2.1.3 The CDRH Office of Compliance can be reached by telephone at (301) 594-4654.

R9-2.1.4 The CFR references may be obtained by searching the Web site at: http://www.access.gpo.gov/nara/cfr/cfr-table-search.html, but these documents do not include figures or tables.

R9-2.1.5 When a laser product is imported, the importing company is considered the laser manufacturer and must certify the laser product.

R9-3 EuropeR9-3.1 International Electrotechnical Commission® 45 (IEC)

R9-3.1.1 European governments have adopted IEC 60825-1 as the laser product safety standard. Manufacturers of laser products should comply with § 2 of the IEC 60825-1 document. An IEC committee is currently working on a checklist for laser product manufacturers to follow to assess compliance with the IEC document. Other IEC 60825 series documents may apply to the product either now or in the future.

R9-3.1.2 EN 60825-1 is the normative standard, which has been adopted by the European Union and EFTA countries.

R9-3.1.2.1 The EN 60825-1 should be available through the various European government agencies or government printing offices.

R9-3.1.3 The laser product manufacturer should review ISO 11553 for requirements that apply to laser equipment that processes materials.

R9-3.1.4 The IEC document can be obtained from: International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, 1211 Geneva 20, Switzerland. Telephone: +41.22.919.02.11; Fax: +41.22.919.03.00; or other participating national standards association (available on Web sites).

R9-3.1.5 The ISO document can be obtained from: International Standards Organization (ISO), 1, rue de Varembé, Case postale 56, CH-1211 Genève 20, Switzerland. Telephone: +41.22.749.01.11; Fax: +41.22.733.34.30; or other participating national standards association (available on Web sites).

45 International Electrotechnical Commission trademark is owned by International Electrotechnical Commission Association.

SEMI S2-0818E © SEMI 1991, 2018 94

R9-3.1.6 The IEC Web site is located at http://www.iec.ch.

R9-3.1.7 The ISO Web site is located at http://www.iso.org/.

R9-4 JapanR9-4.1 The Japanese Safety Association published an English version of the Japanese laser safety standard based on the IEC 60825 series document. This standard is Japanese Industrial Standard JIS C 6802. The Japanese version is still the official standard, but the English version has the warning hazards described with the Japanese symbols in the images.

R9-4.2 As in the IEC document the manufacturing requirements are specified in § 2. There is a companion document JIS C 6801 that provides the Glossary of terms and their translations into English.

R9-4.3 The JIS documents can be obtained through the Japanese Safety Association.

R9-4.3.1 Japanese Standards Association, 1-24 Akasaka 4, Minato-Ku, JP-107 TOKYO, Telephone: +81.3.3583.80.03; Fax: +81.3.3586.20.29; http://www.jsa.or.jp/eng/catalog/frame.html is searchable.

R9-4.4 Web sites:

R9-4.4.1 (In English) http://www.hike.te.chiba-u.ac.jp/ikeda/JIS/index.html

R9-4.4.2 (In Japanese) http://www.jsa.or.jp

R9-5 Other (e.g., Pacific Rim)R9-5.1 The manufacturer is responsible to determine the appropriate standard to use in other countries.

R9-5.2 In the absence of any specific standard for a country, the IEC 60825-1 document should be used as the guide for compliance.

R9-5.3 In many countries, prefectures, states, or provinces, local laser safety regulations exist. Much of this regulation is aimed at the user, but may include product performance requirements. The manufacturer has the responsibility to identify these requirements.

R9-5.4 Addresses of many national standards organizations are found at: http://www.iec.ch/cs1sot-e.htm.

95 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 10 OTHER REQUIREMENTS BY REGION OF USENOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R10-1 Japan — Earth Leakage Breaker/Ground Fault Circuit Interrupter/Ground Fault Equipment Protection Circuit Interrupter/Residual Current DevicesR10-1.1 Japanese regulations may require the use of ground fault circuit interrupter (GFCI), ground fault equipment protection circuit interrupter (GFEPCI), residual current devices (RCD), or earth leakage breaker (ELB) with the equipment.

EXCEPTION 1: The rating of the equipment is less than 20 amperes and less than 150 volts rms.

EXCEPTION 2: The equipment is supplied from the ungrounded secondary of an AC mains isolation transformer.

R10-1.2 The GFCI, GFEPCI, RCD or ELB, when required to satisfy Japanese requirements, should have trip ratings of not greater than 30 mA and 0.1 second.

EXCEPTION 1: If there is no accessible live circuit during maintenance tasks, trip ratings of up to 300 mA are acceptable.

EXCEPTION 2: If the equipment satisfies Exception 1 and the earth impedance is less than 50 ohms, a GFCI, GFEPCI, RCD or ELB of 500 mA maximum is acceptable.

EXCEPTION 3: If the equipment is connected to a source of supply that is provided with a GFCI, GFEPCI, RCD or ELB, an additional GFCI, GFEPCI, RCD or ELB is not required for the equipment.

R10-2 USAR10-2.1 Nameplates — In addition to the nameplate criteria noted in the Electrical section of SEMI S2, equipment evaluated as ‘Industrial Machinery’ per NFPA 79 and intended for use in the United States may be required to display additional nameplate information, such as ampere rating of the largest motor or load, short circuit current rating of the control panel, and the electrical diagram number(s) or the number of the index to the electrical diagrams. Furthermore, where overcurrent protection is provided, the equipment must be marked “overcurrent protection provided at machine supply terminals.”

R10-2.2 Hazard Communication — Federal government OSHA regulations, found in 29 CFR 1910.1200, establish various requirements for labeling of containers of hazardous chemicals and providing Material Safety Data Sheets.

R10-3 EuropeR10-3.1 Nameplates — In addition to the nameplate criteria noted in the Electrical section of SEMI S2, equipment evaluated as ‘Industrial Machinery’ per IEC 60204-1 and intended for use in Europe may be required to display additional nameplate information, such as: certification mark, where required; current rating of the largest motor or load; short-circuit rating of the equipment; and the electrical diagram number(s) or the number of the index to the electrical drawings.

R10-3.1.1 Where only a single motor controller is used, this information may instead be provided on the machine nameplate where it is plainly visible.

R10-3.1.2 The full-load current shown on the nameplate shall be not less than the combined full-load currents for all motors and other equipment that can be in operation at the same time under normal conditions of use. Where unusual loads or duty cycles require oversized conductors, the required capacity shall be included in the full-load current specified on the nameplate.

R10-3.2 European Union requires compliance to CE marking.

R10-4 Worldwide — Hazard Alert LabelsR10-4.1 USA — Labels intended for use in the USA should conform to ANSI Z535.4.

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R10-4.2 Other Countries — Labels intended for use in countries other than the USA should conform to ISO 3864.

97 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 11 LIGHT TOWER COLOR AND AUDIBLE ALERT CODESNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R11-1 Colors for Light TowersR11-1.1 Where used for safety, a light tower should have the following characteristics:

Table R11-1 Light Tower Color Code

Color Explanation Examples

Red Hazardous, dangerous or abnormal condition requiring immediate attention

Pressure/temperature out of safe limits;Voltage drop; BreakdownOvertravel of a stop positionIndication that a protective device has stopped the machine (e.g., overload).

Yellow Abnormal, caution/marginal condition;Change or impending change of critical condition requiring monitoring and/or intervention (e.g., by re-establishing the intended function)

Pressure/temperature exceeding normal limitsTripping of protective device Automatic cycle or motors running; some value (pressure, temperature) is approaching its permissible limit. Ground fault indication. Overload that is permitted for a limited time.

Green Normal condition; machine ready Pressure/temperature within normal limitsIndication of safe condition or authorization to proceed. Machine ready for operation with all conditions normal or cycle complete and machine ready to be restarted.

R11-2 Audible Alert (Buzzer) CodeR11-2.1 Where used for safety, audible alert (buzzer) for the light tower should have the following characteristics:

Table R11-1 Light Tower Buzzer Code

Color Audible Alert (Buzzer)

Red ContinuousYellow IntermittentGreen Intermittent/no sound (selectable)

SEMI S2-0818E © SEMI 1991, 2018 98

RELATED INFORMATION 12 SURFACE TEMPERATURE DOCUMENTATIONNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on October 21, 1999.

R12-1 IntroductionR12-1.1 The following is some of the research leading to the values in Table 1 in § 18 of this Safety Guideline.

R12-1.2 The proposed Hazardous Temperature Limits were derived from UL 195046 and IEC 95047 by adding ambient temperature (25°C) to the maximum temperature rise allowed for external parts of information technology equipment. Because several SEMI members have questioned whether these limits might subject operators and maintenance personnel to contact with potentially hazardous temperatures, a review has been done of several other sources of suggested temperature limits.

R12-1.3 The proposed hazardous surface temperatures for handling and touching of metal handles, knobs, etc., for brief periods in normal use is 60°C. Assuming a brief handling time to be 5 seconds or less, this limit is supported in MIL-STD-1472,48 MIL-HDBK-759A,49 and EN 56350 (which are the same or more conservative by 2°C), and is equal to the pain and tissue damage threshold listed in the Human Factors Design Handbook.51 Thus, this temperature limit seems appropriate for momentary (five seconds or less) contact with uncoated metal handles, knobs, etc., and other material with high thermal conductivity.

R12-1.4 The proposed hazardous surface temperatures for handling and touching of glass/porcelain handles, knobs, etc., for brief periods in normal use is 70°C. This temperature limit is supported by MIL-STD-1472 and EN 563. MIL-HDBK-759 is not applicable because it must be assumed that it applies only to material with high thermal conductivity.

R12-1.5 The proposed hazardous surface temperatures for handling and touching of plastic/rubber handles, knobs, etc., for brief periods in normal use is 85°C. This temperature limit is similarly supported by MIL-STD-1472 and EN 563. MIL-HDBK-759 is not applicable.

R12-1.6 The proposed hazardous surface temperatures for continuous handling and touching of metal handles, knobs, etc., during normal usage is 55°C. It is suggested, based on observations of semiconductor equipment in use, that a continuous handling time of one minute be used. With this duration, the limit of the MIL-STD and the MIL-HDBK ranges from 49°C to 52°C. The EN 563 burn threshold limit for contact with metal for one minute is 51°C. The burning heat pain level listed in the Human Factors Design Handbook is 49°C (no time frame given; assume high thermal conductivity material). Thus, the proposed temperature limit appears to be somewhat high for reasonably foreseeable extended handling contact with uncoated metal handles, knobs, etc., and other material with high thermal conductivity. The § 18 Table 1 limit is 51°C, which might be somewhat painful to more sensitive personnel, but should not result in tissue damage.

R12-1.7 The proposed hazardous surface temperatures for extended handling and touching of glass/porcelain handles, knobs, etc., during normal usage (again assuming 1 minute) is 65°C. The limit of MIL-STD-1472D is 59°C for ‘prolonged contact’ with glass. The EN 563 burn threshold limit at 1 minute is 56°C. Thus, the proposed temperature limit appears to be slightly high for reasonably foreseeable extended handling contact with glass/porcelain surfaces of moderate thermal conductivity. The § 18 Table 1 limit is 56°C, which is the more conservative of the recommendations. This limit could be raised based upon the results of the risk assessment for actual and foreseeable normal usage.

46 Underwriters Laboratory, 2600 N.W. Lake Road, Camas, WA 98607-8542, USA; Telephone: +1.877.854.3577, Fax: +1.360.817.6278, http://www.ul.com47 International Electrotechnical Commission, 3 rue de Varembé, Case Postale 131, CH-1211 Geneva 20, Switzerland; Telephone: +41.22.919.02.11, Fax: +41.22.919.03.00, http://www.iec.ch48 United States Military Standards, Available through the Naval Publications and Forms Center, 5801 Tabor Avenue, Philadelphia, PA 19120-5099, USA; Telephone: +1.215.697.3321.49 MIL-HDBK-759A, Handbook for Human Engineering Design Guidelines, 1981 (Military Handbook)50 EN 563, Safety of Machinery – Temperatures of Touchable Surfaces, 1994 (European Normative Standard)51 Human Factors Design Handbook, Second Edition, Woodson, Tillman & Tillman, 1992 (Reference)

99 SEMI S2-0818E © SEMI 1991, 2018

R12-1.8 Similarly, the proposed hazardous surface temperatures for extended handling and touching of plastic/rubber handles, knobs, etc., during normal usage (again assuming 1 minute) is 75°C. The limit of MIL-STD-1472D is 69°C for ‘prolonged contact’ with plastic. The EN 563 burn threshold limit at 1 minute is 60°C. Thus, the proposed temperature limit again appears to be slightly high for reasonably foreseeable extended handling contact with plastic/rubber surfaces of low thermal conductivity. The § 18 Table 1 limit is 60°C, which is the more conservative of the recommendations. This limit could be raised based upon the results of the risk assessment for actual and foreseeable normal usage.

R12-1.9 The proposed hazardous surface temperatures for external surfaces and internal parts which may be touched are 70°C for metal, 80°C for glass/porcelain, and 95°C for plastic/rubber. It is assumed that this limit applies to inadvertent touching by the operator/maintenance person, resulting in the person instantly breaking contact with the hot surface. There are no analogs in either the MIL-STD or the MIL-HDBK for these temperature limits. The EN 563 burn threshold range for one-second contact with uncoated metal is 65°C to 70°C, while the range for one-second contact with glass is 80°C to 86°C. The proposed temperature limit appears to be slightly high for reasonably foreseeable inadvertent contact with external metal surfaces. The § 18 Table 1 limit for contact with external metal surfaces is 65°C, which is the conservative end of the EN 563 range.

R12-1.10 No information was available to support or refute the temperature limits for contact with external plastic/rubber surfaces. With regard to internal parts, the proposed temperature limits may be adequate given the foreseeable cooling which would likely occur prior to handling of internal parts. The actual thermal lag of components likely to be handled could be verified by thermocouple readings on specific equipment during a risk assessment.

Table R12-1 Allowable Surface Temperatures (°C) for Handles, Knobs, Grips, etc., Held for Short Periods Only (5 seconds or less)

Metal Glass, Porcelain, Vitreous Material

Plastic, Rubber

EN 563 58 70 N/AMIL-STD-1472 60 68 85MIL-HDBK-759 60 N/A N/A§ 18 , Table 1 Value 60 70 85

Table R12-2 Allowable Surface Temperatures (°C) for Handles, Knobs, Grips, etc., Held in Normal Use

Metal Glass, Porcelain, Vitreous Material

Plastic, Rubber

EN 563 51 56 60MIL-STD-1472 49 59 69MIL-HDBK-759 52 N/A N/A§ 18 , Table 1 Value 51 56 60

Table R12-3 Allowable Surface Temperatures (°C) for External Surface of Equipment Which May Be Momentarily Touched

Metal Glass, Porcelain, Vitreous Material

Plastic, Rubber

EN 563 65–70 80–86 N/AMIL-STD-1472 N/A N/A N/AMIL-HDBK-759 N/A N/A N/A§ 18 , Table 1 Value 65 80 95

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Table R12-4 Allowable Surface Temperatures (°C) for Parts, Inside the Equipment, Which May Be Momentarily Touched

Metal Glass, Porcelain, Vitreous Material

Plastic, Rubber

EN 563 N/A 68 85MIL-STD-1472 N/A N/A N/AMIL-HDBK-759 N/A N/A N/A§ 18 , Table 1 Value 65 80 95

101 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 13 RECOMMENDATIONS FOR DESIGNING AND SELECTING FAIL-TO-SAFE EQUIPMENT CONTROL SYSTEMS (FECS) WITH SOLID STATE INTERLOCKS AND EMONOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on July 2003.

196:[197:] Determination of the suitability of this material is solely the responsibility of the user.

R13-1 Safety PhilosophyR13-1.1 The following documents should control applicability of criteria in order of precedence as shown:

1. regulatory codes and standards

2. applicable sections of SEMI S2

3. SEMI Safety Guidelines

4. this Related Information

5. other appropriate standards for functional safety

R13-2 PurposeR13-2.1 This Related Information describes approaches to using alternative technology and technical concepts to achieve functional safety in semiconductor manufacturing equipment.

R13-2.2 Who Can Make Use of this Related Information — Recommendations for designing and selecting fail-to safe control systems (FECS) with solid state interlocks and EMO may be used by semiconductor equipment manufacturers, system integrators, end users and suppliers of automation systems as well as independent third parties.

R13-3 ScopeR13-3.1 Applicability — This Related Information applies to facilities, equipment and machinery used to manufacture, measure, assemble and test semiconductor products and therefore need a high level of safety to protect people, machines, the environment and the industrial processes.

R13-3.2 This Related Information is intended for use by semiconductor equipment manufacturers, system integrators, end users and suppliers of automation systems as well as independent third parties as an orientation to design and architecture of automation systems based on safety-related components. The safety-related automation system executes safety functions to bring the equipment into a safe condition or to maintain it in a safe condition when a hazardous event occurs.

R13-3.3 This Related Information specifies a technical concept for equipment control systems, which does not require the exclusive use of hardwired electromechanical safety components.

R13-3.4 Contents — This Related Information contains the following sections:

1. Purpose

2. Scope

3. Limitations

4. Referenced Standards and Documents

5. Terminology and Definitions

6. State-of-the-Art Safety Control System – Comprised of Solid State Electronics

7. Philosophy and General Concepts

SEMI S2-0818E © SEMI 1991, 2018 102

8. Guide to Assessment and Test Methods

9. Safety Performance

10. Application Examples

11. Related Documents

NOTICE: SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the Documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.

R13-4 LimitationsR13-4.1 This Related Information does not contain the technical detail necessary to design equipment control systems.

R13-4.2 This Related Information is not intended to be used to verify compliance to local regulatory requirements.

R13-4.3 It is not the philosophy of this Related Information to give advice on what must be done to achieve a certain safety performance for equipment control systems, but it gives advice on how to achieve a specified level of safety functionality using industrial controllers (e.g., programmable logic controllers), distributed input/output (I/O) functions and network communications.

R13-4.4 Where references to standards have been incorporated into this Related Information. These references do not imply applicability of the entire standards, but only of the sections referenced.

R13-4.5 Because of the variety of uses for FECS described in this Related Information, those responsible for the application and use of FECS must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards. The illustrations, charts and layout examples shown in this Related Information are solely for purposes of example.

R13-5 Referenced Standards and DocumentsR13-5.1 SEMI Standards and Safety Guidelines

SEMI E54 — Specification for Sensor/Actuator Network

SEMI E81 — Provisional Specification for CIM Framework Domain Architecture

SEMI E98 — Provisional Standard for the Object-Based Equipment Model (OBEM)

SEMI S10 — Safety Guideline for Risk Assessment and Risk Evaluation Process

R13-5.2 ANSI Standards52

ANSI/IEEE C95.1 (United States) — Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields

ANSI/ISA S84.01-1996 — Application of Safety Instrumented Systems for the Process Industry

ANSI/RIA R15.06 (United States) — Industrial Robots and Robot System – Safety Requirements

R13-5.3 DIN V VDE Standard53

DIN V VDE 0801 — Principle for Computers in Safety Related Systems

R13-5.4 IEC Standards54

197:[198:] International standards bodies are indicated, with the equivalent national standards shown in parenthesis.

52 American National Standards Institute, 25 West 43rd Street, New York, NY 10036, USA; Telephone: +1.212.642.4900, Fax: +1.212.398.0023, http://www.ansi.org53 VDE-Verlag GmbH, Bismarkstrasse 33, 10625 Berlin, Germany, http://www.vde.de54 International Electrotechnical Commission, 3 rue de Varembé, Case Postale 131, CH-1211 Geneva 20, Switzerland; Telephone: +41.22.919.02.11, Fax: +41.22.919.03.00, http://www.iec.ch

103 SEMI S2-0818E © SEMI 1991, 2018

IEC 60204-1 (EN 60204-1) — Safety of Machinery – Electrical Equipment of Machines – Part 1: General Requirements

IEC 61010-1 (EN 61010-1) — Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use – Part 1: General Requirements

IEC 61508 (EN 61508) — Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems

198:[199:] IEC 61508 consists of 7 parts, IEC 61508-1 through IEC 61508-7.

R13-5.5 ISO Standards55

199:[200:] International standards bodies are indicated, with the equivalent national standards shown in parenthesis.

ISO 10218 (EN 775) — Manipulating Industrial Robots-Safety

ISO 13849-1 (EN 954-1) — Safety of Machinery-Safety-Related Parts of Control Systems

ISO 13849-2 (EN 954-2) — Safety of Machinery-Safety-Related Parts of Control Systems – Part 2 Validation

ISO/IEC 13850 (EN 418) — Safety of Machinery – Emergency Stop – Principles of Design

ISO 14118 (EN 1037) — Safety of Machinery – Prevention of Unexpected Start-Up

ISO 14119 (EN 1088) — Safety of Machinery-Interlocking Devices Associated with Guards – Principles for Design and Selection

ISO 14121 (EN 1050) — Safety of Machinery-Principles of Risk

200:[201:] National and local Codes and Standards must be applied as required by the installation location. Examples of some that might apply are included below.

R13-5.6 National Fire Protection Association56

NFPA 79 (United States) — Electrical Standard for Industrial Machinery

R13-5.7 VDI® 57 Standard58

VDI/VDE 2180 Bl.2 (Germany) — Safety of Process Control Technology

NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

R13-6 TerminologyR13-6.1 Abbreviations and Acronyms

R13-6.1.1 ATL — approved testing laboratory

R13-6.1.2 CAT. 4 — category 4 (according to ISO 13859-1)

R13-6.1.3 CPU — central processing unit

R13-6.1.4 EMO — emergency off

R13-6.1.5 EUC — equipment under control

R13-6.1.6 FD — field device

R13-6.1.7 FECS — fail-to-safe equipment control system

R13-6.1.8 GUI — graphical user interface

R13-6.1.9 I/O — input/output

55 International Organization for Standardization, ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland; Telephone: +41.22.749.01.11, http://www.iso.org56 National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02269, USA; Telephone: +1.617.770.3000, Fax: +1.617.770.0700, http://www.nfpa.org57 VDI trademark is owned by Association of German Engineers eV.58 VDE-Verlag GmbH, Bismarkstrasse 33, 10625 Berlin, Germany. http:// www.vde.de

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R13-6.1.10 IFD — intelligent field device

R13-6.1.11 ISFD — intelligent safety field device

R13-6.1.12 PLC — programmable logic controller

R13-6.1.13 SIL — safety integrity level (according to IEC 61508)

R13-6.1.14 SRM — safety relay module

R13-6.2 Definitions

R13-6.2.1 certified — evaluated and approved for use in a particular intended function in conformance with a recognized standard by an accredited testing laboratory (ATL).

201:[202:] See SEMI S2 for definition of ATL.

R13-6.2.2 combined I/O — I/O systems of an FECS in which non-safety-related and safety-related signal modules are combined (see R13-8.3.1.1 Figure R13-1).

R13-6.2.3 common cause failure — failure, which is the result of one or more events, causing coincident failures of two or more separate channels in a multiple channel system, leading to system failure.

R13-6.2.4 distributed I/O — input/output modules for sensors and actuators interfacing to a network.

R13-6.2.5 electrical/electronic/programmable electronic (adj.) — based on electrical OR electronic OR programmable electronic technology.

202:[203:] The term above is intended to cover any and all devices or systems operating on electrical principles.

R13-6.2.6 fail-to-safe equipment control system (FECS) — a programmable system of control circuits designed and implemented for safety-related functions in accordance with internationally recognized standards such as ISO 13849-1 (EN 954-1) or IEC 61508. These systems (e.g., safety PLC, safety-related I/O modules) diagnose internal and external faults and react upon detected faults in a controlled manner in order to bring the equipment to a safe state.

R13-6.2.7 field device (FD) — sensors and actuators such as valves (electrical or pneumatic), temperature sensors, proximity switches, pumps, motors, etc.

R13-6.2.8 functional safety — the overall safety design related to the EUC and the EUC control system. Effective functional safety includes the correct functioning of the electrical, electronic, or programmable-electronic safety-related systems; or on other-technology safety-related systems and may include risk reduction measures.

R13-6.2.9 industrial controller — general term for controller-technology, which includes PLC and PC-based technology.

R13-6.2.10 intelligent field device (IFD) — sensors and actuators that use local intelligence to perform functions such as communication, diagnosis and interfacing to a network.

R13-6.2.11 network — general term for bus technology, which includes field bus technology used in control applications.

R13-6.2.12 programmable logic controller (PLC) — microprocessor based controller for sequential control; the control logic of which can be changed through a programming device connected to the controller (e.g., programming panel, host computer, handheld terminal) either directly or remotely through a network.

R13-6.2.13 random hardware failure — failure, occurring at a random time, which results from one or more of the possible degradation mechanisms in the hardware.

R13-6.2.14 safety function — function to be implemented by an electrical or electronic or programmable electronic safety-related system, other technology safety-related system or external risk reduction facilities, which is intended to achieve or maintain a safe state for the EUC, in respect of a specific hazardous event.

R13-6.2.15 safety integrity — probability of a safety-related system satisfactorily performing the required safety functions under all the stated conditions within a stated period of time.

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R13-6.2.16 safety integrity level (SIL) — discrete level (one out of a possible four) for specifying the safety integrity requirements of the safety functions to be allocated to the electrical or electronic or programmable electronic safety-related systems, where safety integrity level 4 has the highest level of safety integrity and safety integrity level 1 has the lowest.

R13-6.2.17 safety network — a network certified for safety applications (this can also be a subpart of a standard network).

R13-6.2.18 safety PLC — a programmable logic controller and associated I/O, certified as having the necessary safety integrity to execute the safety-related function.

R13-6.2.19 safety relay (SR) — a positive or force-guided relay, that is used in safety relay modules (SRMs) to achieve a fail-to-safe circuit.

R13-6.2.20 safety relay module (SRM) — redundant self-monitoring electro-mechanical/ solid state device certified for use in safety applications.

R13-6.2.21 safety-related I/O modules — I/O modules capable of diagnosing internal and external faults and configured to be redundant (e.g., a second shutdown path is included for output-circuits).

R13-6.2.22 safety-related programmable system — systems designed and implemented for safety functions in accordance with ISO 13849 or IEC 61508. These system types (e.g., safety PLC, safety-related I/O modules) can diagnose internal and external faults and can react upon detected faults in a controlled manner.

R13-6.2.23 safety requirements specification — specification containing all the requirements of the safety functions that have to be performed by the safety-related systems.

R13-6.2.24 solid state electronics — designation used to describe devices and circuits fabricated from solid materials such as semiconductors, ferrites, or thin films as distinct from devices and circuits making use of electromechanical technology (e.g., solid state relay, micro controller).

R13-6.2.25 systematic failure — failure related in a deterministic way to a certain cause, which can only be eliminated by a modification of the design or of the manufacturing process, operational procedures, documentation or other relevant factors.

R13-7 State-of-the-Art Safety Control System — Comprised of Solid State ElectronicsR13-7.1 Failure to perform normal function (e.g., a failure of a computer or its software) may cause economic loss, but is not necessarily a safety issue. However, failure of a safety-related component to perform its safety function could result in a hazardous condition. A fail-to-safe system should be designed in a manner to ensure that failures do not result in a hazardous situation. It is therefore important to perform a system risk assessment to determine safety-related functions and the safety performance required. The process outlined in following figure should be followed.

SEMI S2-0818E © SEMI 1991, 2018 106

Figure R13-1 Roadmap to Risk Assessment and System Design

R13-7.2 Safety Interlocks — Semiconductor manufacturing equipment requires the use of fast, reliable and efficient means of safety interlocking. Important issues concerning complex machine architectures include availability and diagnostic capabilities for quick troubleshooting.

R13-7.2.1 A FECS should, even in the case of failure, maintain a safe state of the EUC. Therefore, a FECS is able to detect faults and cause the system to go to a safe state. A properly designed FECS—using methods such as self-monitoring for fault detection and subsequent well-defined reaction—can offer high availability and diagnostics.

R13-7.2.2 § 11.6 of SEMI S2 (including exceptions and notes) indicates a preference for electromechanical devices and components, and gives guidance on their use. However, non-electromechanical devices and components are permitted and they can provide necessary risk reduction while maintaining safety performance. § 11.6 , Note 26 of SEMI S2, suggests some tools for investigation of suitability for use. Additionally, IEC 61508, ANSI/ISA S84.01, and ISO 13849-1 (EN 954-1) provide guidance on the safety system design, assessment and maintenance of suitable control systems.

R13-7.2.3 The usage conditions and safety performance should be determined by the finding of a risk assessment as described in SEMI S10. Risk assessment results can then be used to define appropriate SIL levels and Categories.

203:[204:] Emergency Off — § 12.2.2 of SEMI S2 states that the EMO system should consist of electromechanical components. The exceptions give guidance to the design of EMO circuits using alternative technologies. Regional, national or industry standards may have additional requirements (e.g., USA: ANSI/NFPA 79, Europe: EN 60204-1).

R13-7.2.4 Any deviation from the risk level of electromechanical devices must be carefully evaluated (see §  8 of SEMI S2).

R13-7.2.5 Compliance with § 12 of SEMI S2, emergency shutdown will depend on the risk assessment allowed in § 8.3.4.3 of SEMI S2.

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R13-7.3 Software and Programming

R13-7.3.1 The application software or function blocks have to be verified before being used in an FECS. The automation supplier usually provides a range of approved software blocks.

R13-7.3.2 Access for programming of safety-related functions should be restricted within the FECS to trained people.

R13-7.3.3 To program or modify safety-related programs or parts of it, specially trained or qualified personnel are required. Any changes must be documented and stored within the file history.

R13-8 Philosophy and General ConceptR13-8.1 Introduction — An automated machine system mainly comprises components such as industrial controller, drives, I/O, etc. The level of safety performance of equipment can differ depending on the particular application of FECS. However, irrespective of the particular application, the FECS always comprises a series of sensors, logic elements and actuators for safe shutdown or a motion into a safe and stable machine state.

R13-8.1.1 The term FECS according to IEC 61508 Part 2, is equivalent to the terms SIS (safety instrumented system) or SRS (safety related system) in other application areas. The examples in this Related Information show some possible architectures of the logic system. Sensors, final elements and software are discussed in this Related Information. Application handbooks from automation suppliers provide users with valuable information on how to use these components in order to achieve a fail-to-safe, equipment control system.

R13-8.1.2 For traditional semiconductor equipment, non-safety-related and safety-related technology, are separated. In many cases nonsafety-related and safety-related technology are linked, so that signals representing diagnostics, enable, and feedback can be exchanged.

R13-8.1.3 Main Characteristics of Architecture Concepts:

1. Fail-to-safe equipment control system with conventional hardwired safety technology.

2. Fail-to-safe equipment control system with separation between fail-to-safe and standard network technology.

3. Fail-to-safe equipment control systems with combined network technology for transmission of fail-to-safe and standard data on a single medium.

4. Redundancy can be used in all concepts to increase availability. Different redundancy concepts are in use (see Related Information RELATED INFORMATION 13 § RR13-9 ).

5. Visualization on the standard control part and on the fail-to-safe part can be realized with various interfaces on the standard part and on the fail-to-safe part.

R13-8.2 Design of Architecture and Components

R13-8.2.1 Possible Application Areas

1. Semiconductor manufacturing industry

2. Guarding of people, machines, environment and industrial processes

Emergency stop functions,

Emergency off functions,

Emergency shutdown functions,

Light gates,

Guard doors,

Scanners,

Motion control with safety functions,

Motor control with safety functions,

Process valves with safety functions, and

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Process monitoring using safety-related interlocks.

R13-8.2.2 Safety-Related Equipment Control System — The design of FECS should be carried out in accordance with IEC 61508 and applicable parts of the other referenced standards. The safety controller is used to control (open-loop) processes that can immediately achieve a safe condition. An FECS consists of sensors, logic systems and final elements as shown in § RR13-11 . Replacing an existing electromechanical system with a safety controller does not provide a safe system. Sensors and final elements have to be considered as well.

R13-8.2.3 Safety Requirements — The FECS should be suitable for SIL1 to SIL3 safety integrity level in compliance with IEC 61508 or control categories 2 to 4 in compliance with ISO 13849-1 (EN 954-1). The required safety performance requirements will be determined in the system safety risk assessment. For application assessment, local authorities and notified bodies should request a safety handbook and certification according to IEC 61508 or ISO 13849. The safety-related system and its components should be validated to ensure it fulfills the safety requirements (SIL, CAT) determined from the risk analysis.

R13-8.2.4 Principle of the Safety Functions — The FECS executes safety functions to bring the equipment into a safe state or to maintain it in a safe condition when a hazardous event occurs. The safety function for a production process can be realized using a user safety function or a fault response function. The safe state can be achieved by de-energizing the output modules.

R13-8.2.5 Communications — Non-safety-related and safety-related communications between an industrial controller and I/O modules should pass through a standard network system or a safety network system in sequence or through a combined network system (see Figures RR13-8.3.1.1 Figure R13-1 through RR13-8.3.3.1 Figure R13-1). Bridges, routers and repeaters can be used in either standard networks or in safety networks to adapt the network topology to the individual layout of production process and equipment.

R13-8.3 Basic Topologies — §§ RR13-7.3.1 through RR13-7.3.3 describe examples of network-based architectures that are capable of achieving a FECS. The suppliers should take into account performance, timing, ease of use, and other factors when selecting an architecture type.

204:[205:] These examples are not represented to be all-inclusive.

R13-8.3.1 Use of Fail-to-Safe Equipment Control Systems with Conventional Safety Technology — Equipment manufacturers can achieve functional safety by the use of hardwired circuits. Such hardwired circuits are realized with terminals, electromechanical or electronic safety relays, and contactors. The relays would be certified for use in CAT 4 applications according to ISO 13849. In Figure RR13-8.3.1.1 Figure R13-1, a standard industrial controller is used with standard I/O over a standard network to provide for the non-safety aspects of the machine and to provide diagnostics and visualization of the hardwired safety functions.

109 SEMI S2-0818E © SEMI 1991, 2018

Figure R13-1 Fail-to-Safe Equipment Control System with Conventional Safety Technology

R13-8.3.1.2 Use of Fail-to-Safe Equipment Control Systems with Dual Networks for Standard and Fail-to-Safe Communications and Combined Controllers — Figures RFigure R13-1 and RFigure R13-2 are dual network systems with control of the non-safety functions remaining the same as in fail-to-safe equipment control systems (FECS) with Conventional Safety Technology. Safety functions, however, are achieved using FECS with safety-related information and control managed over a separate dedicated safety network.

Figure R13-1 Fail-to-Safe Equipment Control System with Dual Network for Standard and Fail-to-Safe Communication and Separated Standard and Safety Controllers

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Figure R13-2 Fail-To-Safe Equipment Control System with Dual Network for Standard

and Fail-To-Safe Communication and Combined Controller

R13-8.3.2 Fail-to-Safe Equipment Control System with Combined Network for Standard and Fail-to-Safe Communication — In Figures RR13-8.3.2.1 Figure R13-1 and RR13-8.3.2.1 Figure R13-2 the standard network and safety network have been combined into one physical network. The standard controller and the safety controller can physically be consolidated into one single unit. A combined network system is composed of technology that allows the nonsafety-related and safety-related communication to function on the same bus cable. Standard I/O, safety I/O and combined standard/safety I/O can all connect to the network.

Figure R13-1 Fail-to-Safe Equipment Control System with Combined Network for Standard

and Fail-to-Safe Communication and Combined Controller

111 SEMI S2-0818E © SEMI 1991, 2018

Figure R13-2 Fail-to-Safe Equipment Control System with Combined Network for Standard

and Fail-to-Safe Communication and Separated Controller

R13-8.3.3 Fault Tolerant Equipment Control System with High Availability and Redundant Network — In Figures RR13-8.3.1.1 Figure R13-1 through RR13-8.3.2.1 Figure R13-2, the FECS enters a safe-state condition if a failure should occur; however, the production process would be interrupted. In order to increase the availability of the automation system and therefore avoid process downtime resulting from control system faults as well as faults and errors of components such as the power supply, the industrial controller, the network connection, and the I/O modules need to be made redundant. Possible architectures (see R13-8.3.3.1 Figure R13-1) for achieving high availability include 2 oo 2, 2 oo 3, 2 oo 4, etc. (see § RR13-9 ). Using fail-to-safe and high availability systems, injury to people or environmental damage can be prevented and the production process can be continued without interruption.

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Figure R13-1 Fault-Tolerant Equipment Control System with High Availability FECS and Redundant Network

R13-9 Guide to Assessment and Test MethodsR13-9.1 Assessment and testing of an electronic system (especially programmable systems) for safety integrity levels (SIL) according to IEC 61508/ANSI/ISA 84.01 or risk categories according to ISO 13849-1 (EN 954-1) is a complex and time consuming task, requiring a considerable level of knowledge and expertise. The use of components such as safety PLCs and safety networks, that are certified by third parties for use in systems, and include specific SILs and risk categories, simplifies the process of assessing the whole system.

205:[206:] Certified (or listed) components need to be certified for functional safety use in safety critical systems. The final integrated system should be fully assessed; using tools such as IEC 61508/ANSI/ISA 84.01 or ISO 13849-1 (EN 954-1). Assessments can often simplified by using combinations of certified components or FECS.

R13-9.2 Commissioning and Site Approval — Commissioning and site approval as described in IEC 61508 may be confusing and therefore the following criteria are necessary for understanding:

R13-9.2.1 Safety-related components should meet the safety requirements defined during the risk analysis.

206:[207:] Use of Notified Bodies, ATLs or a Professional Engineer to perform system assessment, type approval/site approval/commissioning of electronic components and for machinery with industrial controllers is defined by the jurisdiction of use.

R13-9.2.2 During control system commissioning, all relevant documentation of the pre-inspection should be available. A pre-inspection usually is the first phase of a control system commissioning.

R13-9.2.3 During pre-inspection, control system commissioning protocols should be prepared.

R13-9.2.4 If a safety analysis or safety case has been prepared for the specific installation, all documents regarding this activity should be made available.

R13-9.2.5 Whether a safety analysis or safety case has been prepared or not, a directory of available documents should be generated.

R13-9.2.5.1 This list should include the titles, dates and number of pages of all documents.

R13-9.2.5.1.1 If possible, all documents should also be available in electronic form.

R13-9.2.5.2 The documentation should include:

1. Safety Specification (if possible as formal specification),

2. Top-level diagram of the application (1 or 2 pages),

3. Technical implementation (e.g., block, flow and timing diagrams),

4. Explanation of separation between safety critical and not safety critical parts of the application,

5. Safety handbooks of the system components (safety handbooks of the safety controllers, sensors and actuators),

6. Description of interfaces,

7. Specification of all safety relevant program parts,

8. I/O documentation,

9. Software program documentation,

10. Wiring documents,

11. Diagram and listing of the interaction between input- and output-data (e.g. safety matrix, cause-effect diagrams or comparable documents),

12. Cross reference listing,

13. Source programs on storage medium, and

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14. Description of the procedure to verify, that the documentation, respectively the files on the storage medium, are identical to the programs in the application (upload verify, CRC checksums, or comparable).

R13-10 Safety PerformanceR13-10.1 For details on how to achieve the necessary safety system requirements, see ISO 13849.

207:[208:] An update of document IEC 62061 is currently under preparation, and it should be consulted for further details.

R13-11 Application ExamplesR13-11.1 Safety is important in semiconductor equipment (especially in the area of wafer fabrication) where toxic media (e.g., gases or chemicals), high-speed motion, or lasers may be present. The following are examples of some wafer fabrication equipment which could be adapted to a FECS:

1. CVD

2. Cleaning Equipment

3. CMP

4. Diffusion/Oxidation

5. Dry Etch Systems

6. Epitaxy

7. Ion Implantation

8. Lithography

9. Physical Vapor Deposition

10. Vacuum Deposition

11. Wet Etch Systems

R13-12 Related DocumentsR13-12.1 DIN V VDE Standard59

DIN V VDE 19250 — Control Technology; Functional Safety Aspects to be Considered for Measurement and Control Equipment

59 VDE-Verlag GmbH, Bismarkstrasse 33, 10625 Berlin, Germany. http:// www.vde.de

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RELATED INFORMATION 14 ADDITIONAL CONSIDERATIONS FOR FIRE SUPPRESSION SYSTEMSNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on March 18, 2004.

R14-1 IntroductionR14-1.1 Preventing discharges from occurring accidentally and ensuring that systems are able to fulfill their intended function requires attention to detail from the specification of the system, through design, installation and commissioning and then through on-going maintenance.

R14-1.2 The following information is intended to assist stakeholders involved in the process of designing, installing, and maintaining fire protection of semiconductor manufacturing equipment. Further information can be found in the appropriate fire protection codes and standards applicable to the type of fire protection system and in related documents.

208:[209:] The term ‘fire suppression’ is limited to extinguishing fire, once it has begun. The term ‘fire protection’ incorporates fire suppression and other means of mitigating the risk of fires, including fire detection and materials selection.

R14-1.3 The use of contractors with previous experience in the design and installation of fire protection of cleanrooms and semiconductor manufacturing equipment is desirable.

R14-1.4 Independent third party review of fire protection designs and installations by a fire protection engineer with relevant experience can also help to ensure that systems are correctly designed and installed.

209:[210:] The material in this Related Information is presented as additional guidance in designing, installing, and maintaining fire protection systems in semiconductor manufacturing equipment. Although this information is believed to be useful in optimizing such systems, the material in this Related Information does not comprise additional criteria for determining conformance to the provisions of SEMI S2 or SEMI S14.

R14-2 Design ReviewR14-2.1 Ensure that system proposed uses approved or listed components and that they are used within their listing or approval (e.g., FM Approved® 60 wet bench fire suppression systems should be used for open-faced wet bench whereas an enclosed tool can use a system comprising of FM® 61 approved and compatible components).

R14-2.2 Detection needs to be selected to suit the working environment and the type of fire/smoke that is anticipated (e.g., optical detectors need to have been tested and approved/listed for use with specific flammable liquids or gases). Flames and smoke from burning materials have varying physical characteristics which mean that some detection devices will not always react promptly.

R14-2.3 The location of detection devices in relation to hazards needs to be carefully considered. A detector that is located too close to a heat source may activate when it sees normal process conditions rather than fire conditions.

R14-2.4 Some optical detectors may also be susceptible to accidental activation if they are exposed to welding flashes. Care in detector selection can avoid this, but implementing strict cutting and welding working practices and permissions can also play an important part.

R14-3 Installation ReviewR14-3.1 Once completed by the fire protection installer, the fire protection installation should be inspected and reviewed by a competent and experienced fire protection engineer. This review will:

R14-3.1.1 Verify installation against previously working drawings.

R14-3.2 Ensure that specified equipment has been installed as indicated on the working drawings and in line with equipment approvals and listings.

60 FM Approved trademark is owned by FM Approvals LLC.61 FM trademark is owned by FM Approvals LLC.

115 SEMI S2-0818E © SEMI 1991, 2018

R14-3.3 Distribution pipework networks should be complete (including all connections), properly supported using listed and approved equipment. Frequent failures of piped systems, including CO2 systems, occur due to incorrectly connected pipes or where fittings have not been made or sufficiently tightened.

R14-3.4 Supports for pipework should be able to withstand the expected forces that will be experienced during discharge of the suppression system. This is important to protect personnel and property from moving pipes in high-pressure systems using agents such as carbon dioxide.

R14-3.5 Detection systems should have components installed as per reviewed drawings, however it is not always possible during desktop drawing review to identify that detectors are correctly sited. As a result, the field review should concentrate on ensuring that components are located so that they can see the hazard without obstruction, including clear vision panels, which may prevent detector from ‘seeing’ the flame.

R14-3.6 Similarly, detectors need to be sited so that they will not experience normal process temperatures, radiation or be exposed to chemical, liquid or particles that could result in an accidental activation.

R14-3.7 Where linear heat detection cable is used it should be located where it will not be exposed to levels of ambient or process related heat that could trigger an alarm signal. In addition, the cable should be securely attached to prevent it dislodging and coming into contact with hot surfaces.

R14-3.8 Nozzle locations in many suppression systems can be critical to ensuring functionality, reliability and safety (e.g., CO2 nozzles incorrectly positioned can result in chemical splashing or dislodging product or quartzware). If nozzles are exposed to chemical action including corrosive chemicals, it is important that the materials are resistant to the chemical.

R14-3.9 Where automatic sprinkler heads are used, the fusible link should be adequately protected from chemical and mechanical attack.

R14-4 Commissioning TestsR14-4.1 All installations should undergo a thorough commissioning and acceptance test conducted by the installer and witnessed by the owner or owner’s representative.

R14-4.2 Functional Tests are essential, but not sufficient to ensure that system will operate as intended. The types of problems that can be picked up by functional testing are:

R14-4.2.1 Inability of detection system to detect as intended,

R14-4.2.2 Inability of control system to receive signal from individual detectors, and

R14-4.2.3 Inability of alarm panel to initiate system discharge or send alarm signals to connected devices and safety systems, for example:

local or remote alarm panels,

sounders and warning devices, and

interlocks to equipment shutdown and safety systems, EMO.

R14-4.3 Discharge Testing is the only way that we can ensure that that a system will fulfill its intended function. The types of problems that can be picked up by discharge testing are:

R14-4.3.1 Lack of extinguishing agent.

R14-4.3.2 Inability to transfer agent from supply to nozzles due to:

Blockages arising from incorrect equipment,

Incomplete piping, loose fittings and supports, and

Installation, design problems (e.g., icing up of CO2 pipes or nozzles).

R14-4.4 In many cases discharge testing within the cleanroom environment is not considered acceptable or practical. Accordingly, alternatives such as type testing can prove that the design will provide the necessary protection, but may need to be supplemented by a more rigorous commissioning test of the final systems. Type testing would involve the installation and discharge testing of a system on a tool during manufacture or on a mockup

SEMI S2-0818E © SEMI 1991, 2018 116

of the tool. The aim would be to prove that distribution pipework and nozzles have been correctly designed and that the concentration of agents and distribution patterns from nozzles is acceptable. This would be supplemented by additional tests on each installation, including pressure tests of pipework and ‘puff’ tests to verify pipework integrity.

R14-5 Burn InR14-5.1 In order to avoid unnecessary discharges, a period of burn-in for the detection system is advisable. This involves the detection system operating, enabling detection of fires and initiation of alarms, but the detection is not interlocked to shut down the process equipment or initiate a discharge.

R14-5.2 A period of days or weeks may be appropriate depending on the effect of an accidental activation of the system in terms of interruption to processing, damage to product or contamination of the environment.

R14-6 Maintenance and ServicingR14-6.1 Once systems are installed and commissioned it is important that the routine inspection and maintenance procedures recommended by manufacturers and those required by codes and standards, are adequately implemented.

R14-6.2 The inspection frequencies may need to be modified if the ambient conditions can adversely affect the protection systems (e.g., sprinkler heads protecting corrosive fume exhaust ducts may need to be inspected weekly or monthly until the appropriate frequency for that particular system can be determined).

R14-6.3 Annual and semiannual maintenance should be carried out by competent personnel with adequate training for the tasks in hand.

117 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 15 REMOTE OPERATIONNOTICE: This Related Information is not an official part of SEMI S2 and was derived from practical application by task force members and from SEMATECH® 62 e-Diagnostics Guidebook Version 2.1. This Related Information was approved for publication by full letter ballot procedures on September 5, 2007.

R15-1 Referenced Standards and DocumentsR15-1.1 SEMI Standards and Safety Guidelines

SEMI E30 — Generic Model for Communications and Control of Manufacturing Equipment Model (GEM)

R15-1.2 International SEMATECH Document63

01084153D-ENG — e-Diagnostic Guidebook: Version 2.1

R15-2 Factory AutomationR15-2.1 Semiconductor fabrication facilities have become increasingly automated over the last 10 to 15 years. With the introduction of 300 mm wafer equipment, control by the facility’s manufacturing execution system (MES) is becoming the norm.

R15-2.2 The user interfaces on 300 mm SME are now unattended much of the time. Indications and messages formerly intended for local operators will go unobserved if they are not also directed toward the facilities MES, using the message formats of SEMI E30 and related standards.

R15-3 Equipment Control States in SEMI E30R15-3.1 SEMI E30 describes equipment states relevant to control by the MES. SME can be ON-LINE, OFF-LINE, or HOST OFF-LINE. The transition between ON-LINE and OFF-LINE is controlled by a person at the SME user interface. The transition from ON-LINE to Host OFF-LINE happens in response to a command (command string = ‘S1F15’) from the MES. When the SME is in HOST OFF-LINE state it will transition to ON-LINE when commanded by the MES (command string = ‘S1F17’).

R15-3.2 Equipment that is ON-LINE can either be in a Local substate (ON-LINE/LOCAL) or a Remote substate (ON-LINE/REMOTE). The ON-LINE/REMOTE state is the state for normal automated operation under control of the MES. The transition between Local and Remote substates is controlled by a person at the SME user interface.

R15-3.3 In the ON-LINE/LOCAL state, the SME will not execute many commands from the MES, in particular the SME should not execute host commands to initiate physical movement or to begin processing. Neither using this control nor physically braking the communications link is a form of, or a substitute for, hazardous energy isolation (HEI).

R15-3.4 SEMI E30 provides for a control at the User Interface to disable communication. In order to prevent or stop remote operation the person at the User Interface needs to use this control or physically break the communications link (e.g., disconnect the communications cable).

R15-4 Remote OperationR15-4.1 Remote operation under control of the MES is limited to commands and data transfer described in the Information and Control Standards (SEMI E30, etc.). This is operational control and also includes recipe management, which can change some operational parameters.

R15-4.2 A person remotely controlling the SME from the supplier’s site has the same ability to control transitions between ON-LINE and OFF-LINE states and between LOCAL, and REMOTE substates as a person at the user interface.

62 SEMATECH trademark is owned by SEMATECH, Inc.63 SEMATECH, 257 Fuller Road, Suite 2200, Albany, NY 12203, USA; Telephone: +1.518.649.1000, http://www.sematech.org

SEMI S2-0818E © SEMI 1991, 2018 118

R15-4.3 A technician at the SME user interface has a greater range of control than operation controlled by the MES. Software can be revised and downloaded, operational limits can be changed and alarm set points can be changed. Consequently, there is greater risk of harm to the equipment and its operators.

R15-5 Communication SecurityR15-5.1 The SEMATECH e-Diagnostics Guidebook v2.1 provides for a secure system of communication (called Interface C) between a supplier’s remote location and the equipment within a facility.

R15-6 Exposure to HazardsR15-6.1 From the point of view of a person working on SME, remote operation includes operation controlled by a person on the other side of the world, control by the MES computer on the other side of the facility, and control by a person on the other side of a bulkhead.

R15-6.2 If a person is exposed to a hazard, and a safety feature provided for reducing the risk of the hazard is disabled or defeated, there may be a risk of injury (e.g., due to the equipment starting to operate unexpectedly). Unexpected startup can be initiated by the MES, a local person or a person at a supplier location.

R15-6.3 If an person is exposed to a hazard and a safety feature provided for reducing the risk of the hazard is disabled or defeated, the risk may be reduced by hazardous energy isolation (see § 17 ).

R15-7 SEMATECH E-Diagnostic GuidelinesR15-7.1 Remote operation often provides a person the ability to remotely view and actuate equipment functions as if he or she were present at the SME. This includes the ability to remotely access, load, download, execute, and analyze results from diagnostics, calibrations, recipes, and user programs. Parameters and alarm set points can be changed, and software can be installed or modified.

R15-7.2 The SEMATECH e-Diagnostics Guidebook v2.1 describes safety and security principles for remote equipment operation (REO). Only a few of these principles have been implemented as SEMI Standards or Safety Guidelines.

There should always be a person present at the user interface when control from a supplier location is enabled.

The local person should have the ability to override or stop any remote operation execution.

The local person should be able to terminate remote operation at any time.

The local person should be in communication with the remote location (e.g., by phone, VOIP, video, text messaging).

All interlocks should be enabled.

Remote operation should not have the ability to defeat any interlock or EMO.

Equipment should not be configured so that HPMs can be released under remote operation.

119 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 16 DESIGN PRINCIPLES AND TEST METHODS FOR EVALUATING EQUIPMENT EXHAUST VENTILATION — Design and Test Method Supplement Intended for Internal and Third Party Evaluation UseNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on May 13, 2009.

R16-1 IntroductionR16-1.1 This Related Information provides specific technical information relating to § 22 . In general, it provides guidelines for:

ventilation design for semiconductor manufacturing equipment, and

test validation criteria.

R16-1.2 This Related Information is intended to be used as a starting point for reference during equipment design.

R16-1.3 This Related Information is not intended to limit hazard or test evaluation methods or control strategies (e.g., design principles) employed by manufacturers or users. Many different methods may be employed if they provide a sufficient level of protection.

R16-1.4 This Related Information is not intended to provide exhaustive methods for determining final ventilation specifications. Other methods may be used where they provide at least equivalent sensitivity and accuracy.

R16-1.5 The exhaust velocities, volume flow rates and pressures listed are derived from a mixture of successful empirical testing and regulatory requirements.

R16-1.6 Test validation criteria are generally referenced from the applicable internationally recognized standard. It is the user’s responsibility to ensure that the most current revision of the standard is used.

Table R16-1 Ventilation

Hood Type Recommended Test Methods Typical Design and Test Exhaust Parameters (See #1)

References

Wet Station Primary: vapor visualization, air samplingSupplemental: capture velocity, slot velocity, tracer gas, air sampling

0.28–0.50 m/s (55–100 fpm) capture velocity for non-heated0.36–0.76 m/s (70–150 fpm) capture velocity for heated110–125% of the laminar flow volume flow rate across the top of the deck

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Gas Cylinder Cabinets

Primary: face velocity, tracer gasSupplemental: vapor visualization

1.0–1.3 m/s (200–250 fpm) face velocity

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Equipment Gas Panel Enclosure

Primary: tracer gas, static pressureSupplemental: vapor visualization

4–5 air changes per minute–1.3 to –2.5 mm (–0.05 to –0.1 inch) H2O static pressure

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Diffusion Furnace Scavenger

Primary: face velocity, vapor visualizationSupplemental: tracer gas, air sampling

0.50–0.76 m/s (100–150) fpm face velocityNOTE: Do not use hot wire anemometer.

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

SEMI S2-0818E © SEMI 1991, 2018 120

Hood Type Recommended Test Methods Typical Design and Test Exhaust Parameters (See #1)

References

Chemical Dispensing Cabinets

Primary: static pressureSupplemental: vapor visualization, air sampling where safe, tracer gas where emission rates can be accurately calculated

–1.3 to –2.5 mm (–0.05 to –0.1 in.) H2O static pressure2–3 air changes per minute

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Parts-Cleaning Hoods

Primary: face velocity, vapor visualizationSupplemental: tracer gas, air sampling

0.40–0.64 m/s (80–125 fpm) face velocity

ASHRAE Standard 110Appendix 2 of SEMI S6ACGIH Industrial Ventilation Manual

Pump and Equipment Exhaust Lines

Primary: static pressureSupplemental: tracer gas

–6 to –25 mm (–0.25 to –1.0 in.) H2O static pressure125% maximum volume flow rate from pump

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Glove Boxes Primary: static pressure, tracer gasSupplemental: vapor visualization, air monitoring

No consensus for a reference at the time of publication of this Safety Guideline.

ACGIH Industrial Ventilation ManualAppendix 2 of SEMI S6

Drying/Bake/Test Chamber Ovens

Primary: static pressure, tracer gasSupplemental: vapor visualization, air monitoring

–1.3 to –2.5 mm (–0.05 to –0.1 in.) H2O static pressure

Appendix 2 of SEMI S6ACGIH Industrial Ventilation Manual

Spin-Coater (cup only)

Primary: vapor visualization, velometrySupplemental: air sampling

(see SEMI S2 §§ 23.5.1 through 23.5.3 )

ACGIH Industrial Ventilation Manual

Supplemental Exhaust

Primary: capture velocity, vapor visualization, air sampling

0.50–0.76 m/s (100–150 fpm) capture velocity

ACGIH Industrial Ventilation Manual

#1 All measurements should be within ±20% of average for face velocity, ±10% of average along the length of each slot for slot velocity, and ±10% of average between slots for slot velocity.

R16-2 Exhaust OptimizationR16-2.1 Exhaust optimization is the use of good ventilation design to create efficient equipment exhaust. The design and measurement methods discussed below confirm that equipment exhaust is acting as the manufacturer intended. This information is not meant to prohibit alternate methods of achieving or verifying good ventilation design. References for ventilation design are included at the end of this Related Information.

R16-2.2 Design Recommendations

R16-2.2.1 Equipment exhaust design can attempt to reduce inefficient static pressure losses caused by: friction losses from materials; openings, and duct geometries (elbows, duct expansions or contractions); turbulent air flow; fans; internal fittings such as blast gates and dampers; directional changes in airflow.

R16-2.2.2 Other good design principles can include minimizing distance between the source and hood, and reducing enclosure volumes.

R16-2.2.3 For nonchemical issues such as heat from electrical equipment, heat recapture rather than exhaust may be appropriate.

R16-2.2.4 The possible impact of highly directional laminar airflow found in most fabs should be considered when designing equipment exhaust.

R16-2.3 Recommended Equipment Controls — The location of internal blast gates or dampers inside equipment, and their appropriate settings, should be clearly identified. The number of equipment dampers and blast gates should be minimized. Gates/dampers should be lockable or otherwise securable. Static pressure or flow sensors installed on equipment by the manufacturer should have sufficient sensitivity and accuracy to measure exhaust flowrate fluctuations that place the equipment out of prescribed ranges.

121 SEMI S2-0818E © SEMI 1991, 2018

R16-2.4 Recommended Measurement/Validation Method — Measurements should be made to identify optimal exhaust levels and confirm that safety and process requirements are being addressed. The manufacturer should be able to identify any critical equipment locations for chemical capture, and quantify appropriate exhaust values. Multiple validation/measurement methods may be needed.

R16-2.4.1 Measurements should be done after equipment components are assembled.

R16-2.4.2 Computer modeling can be done to predict exhaust flow and hazardous material transport in equipment by solving fluid mechanics conservation of energy and mass equations. Modeling can be used in the equipment design stage or to improve existing equipment. Computer models should be verified experimentally, using one or more of the methods discussed below.

R16-2.4.3 Tracer gas testing provides a method to test the integrity of hoods by simulating gas emission and measuring the effectiveness of controls. Testing until there is a failure, and then slightly increasing the flow rate until the test is successful can be used to help minimize air flow specifications.

R16-2.4.4 Chemical air or wipe monitoring can be used to confirm that chemical transport is not occurring into unintended areas of the equipment.

R16-2.4.5 Velocity profiling will confirm expected airflows, the direction of flow, and the effect of distance.

R16-2.4.6 Vapor visualization will confirm expected airflows, the direction of flow, and the effect of distance. Vapor visualization is the observation of aerosols (e.g., aerosols generated by using water, liquid nitrogen, or dry ice) so that exhaust flow patterns can be observed. Smoke tubes or aerosols may also be used, however they can produce contamination.

R16-3 Chemical Laboratory Fume Hoods, Parts Cleaning HoodsR16-3.1 Lab fume hoods and part cleaning hoods are designed to control emission by enclosing a process on five sides and containing the emission within the hood.

R16-3.2 Design Recommendations

R16-3.2.1 Fully enclosed on five sides, open on one side for employee access and process/parts placement and removals.

R16-3.2.2 Front (employee access side) should be provided with sliding door and/or sash.

R16-3.2.3 Minimize size of the hood based on process size.

R16-3.2.4 Minimize front opening size based on size of process and employee access needs.

R16-3.2.5 Ensure hood construction materials are compatible with chemicals used.

R16-3.3 Control Specifications — Face velocity is the specification generally used with hoods open on only one side.

R16-3.3.1 Generally acceptable laboratory fume hood face velocities range from 0.40 to 0.60 m/s (80 to 120 fpm) with no single measurement ±20% of average. 0.64 to 0.76 m/s (125 to 150 fpm) is recommended for hoods in which carcinogens or reproductive toxicants may be used.

R16-3.3.2 Air movement in the work area.

R16-3.3.3 An average face velocity of 0.50 m/s (100 fpm) is generally found to be acceptable in most applications.

R16-3.3.4 Face velocities of 0.64 to 0.76 m/s (125 to 150 fpm) may be required when a lab hood is installed in an area with laminar air flow.

R16-3.3.5 Face velocity above 0.76 m/s (150 fpm) should be avoided to prevent eddying caused by a lower pressure area in front of an employee standing at the hood.

R16-3.4 Recommended Measurement/Validation Method

R16-3.4.1 The preferred method is measurement of average face velocity and hood static pressure. Measurements are taken with a velometer or anemometer. Multiple measurements are taken in a grid, at least 10 to 40 per square

SEMI S2-0818E © SEMI 1991, 2018 122

meter (1 to 4 per square foot) of open area, in the plane opening of the hood. This allows representative, evenly spaced measurements to be taken (see also open-surface tanks).

R16-3.4.2 Additional confirmation by visualization check of containment using smoke or vapor testing.

R16-3.4.3 ASHRAE Method 110, or equivalent (use appropriate sections), for tracer gas testing of lab hoods may be used as a supplemental verification provided that an accurate emission rate can be defined. (ASHRAE 110 lists 3 tests: ‘as manufactured,’ ‘as used,’ and ‘as installed.’ The ‘as manufactured’ test is the test that is used most frequently.)

R16-4 Wet StationsR16-4.1 Wet stations are slotted hoods designed to capture laminar air flow while also capturing wet process emissions from the work area. Wet stations can be open on the front, top and both sides (it is usually preferable to enclose as much as possible).

R16-4.2 Design Recommendations

R16-4.2.1 Slots should be provided uniformly along the length of the hood for even distribution of airflow.

R16-4.2.2 Additional lip exhaust slots should be provided around tanks or sinks to control emissions.

R16-4.2.3 The plenum behind the slots should be sized to ensure even distribution of static pressure. These slots should be designed to ensure adequate airflow is provided by the side slots, and to minimize turbulence that could reduce exhaust performance.

R16-4.2.4 Velocity along length of slot should not vary by more than 10% of the average slot velocity.

R16-4.2.5 Additional use of end or side panels/baffles can reduce negative impact of side drafts.

R16-4.2.6 Exhaust volume settings should consider laminar air flow volumes and be balanced to minimize turbulence and to ensure capture.

R16-4.2.7 The station design should consider airflow patterns in the operating zone to minimize turbulent horizontal airflow patterns into and across the work deck.

R16-4.2.8 Additional considerations to reduce exhaust demand include providing covered tanks, and recessing tanks below deck level.

R16-4.3 Control Specifications

R16-4.3.1 Wet station specifications are complicated by the fact that wet stations generally do not have an easily definable face velocity to measure. A number of methods have been used and are all acceptable if used consistently and provided documentation indicates chemical containment meets the 1% of the OEL at distances beyond the plane of penetration at the exterior of the wet station.

R16-4.3.2 Maintain an average capture velocity of 0.33 to 0.50 m/s (65 to 100 fpm) immediately above a bath.

R16-4.3.3 Calculate the total exhaust volume requirement by determining the total volumetric flow of laminar air hitting the deck and increasing this value by 20% to 25%.

R16-4.3.4 For some wet stations that are partially enclosed from the top, an artificial plane opening (‘face’) can be defined where the downward laminar air flow penetrates the capture zone (at ‘face velocity’) of the wet station. Depending on the hood design and laminar air flow provided, average face velocities can range from 0.20 to 0.50 m/s (40 to 100 fpm). The measurement location can greatly influence the measured face velocity; therefore, this method should be supplemented with at least one of the preceding methods for greater accuracy and reproducibility at the user’s facility.

R16-4.4 Recommended Measurement/Validation Method

R16-4.4.1 Confirmation of capture using vapor visualization.

R16-4.4.2 Confirmation of laminar flow of make-up air into the station using vapor visualization.

R16-4.4.3 Tracer gas testing may be used as supplemental verification, provided an emission rate can be accurately defined.

123 SEMI S2-0818E © SEMI 1991, 2018

R16-5 Supplemental ExhaustR16-5.1 Supplemental exhaust, if not designed into the equipment, can be provided by a flexible duct with a tapered hood. This can be placed in the work area to remove potential contaminants before they enter the breathing zone. Supplemental exhaust is frequently used during maintenance or service.

R16-5.2 Design Recommendations

R16-5.2.1 Retractable or movable non-combustible flex ducting for easy reach and placement within 150 to 300 mm (6 to 12 in.) of potential emissions to be controlled.

R16-5.2.2 Manual damper at hood to allow for local control (i.e., shut off when not required).

R16-5.2.3 Tapered hood with a plane opening as a minimum. The additional use of flanges or canopies to enclose the process will result in improved efficiency.

R16-5.3 Control Specifications

210:[211:] This is one equation that is most commonly used. Other equations may be appropriate; see also ACGIH Industrial Ventilation Manual, and Semiconductor Exhaust Ventilation Guidebook.

R16-5.3.1 A minimum capture velocity of 0.50 m/s (100 fpm) is required at the contaminant generation point for releases of vapor via evaporation or passive diffusion. Ventilation should not be relied upon to prevent exposures to hazardous substances with release velocities (e.g., pressurized gases). For a plane open ended duct without a flange, the air flow required at a given capture velocity can be calculated by:

Q = V(10X2 + A) (R17-1)

where:

Q = required exhaust air flow in m3/s (cfm)

V = capture velocity in m/s (fpm) at distance X from hood

A = hood face area in square meters (square feet)

X = distance from hood face to farthest point of contaminant release in meters (feet). NOTE: This is only accurate when X is within 1.5 diameters of a round opening, or within 0.25 circumference of a square opening.

R16-5.4 Recommended Measurement/Validation Method

R16-5.4.1 Measurement of capture velocity at farthest point of contaminant release. Measurements taken with a velometer or anemometer.

R16-5.4.2 Confirmation by visualization check of capture using vapor capture testing.

R16-6 Equipment Gas Panel EnclosuresR16-6.1 Equipment gas panel enclosures, also known as gas boxes, jungle enclosures, gas jungle enclosures, valve manifold boxes, and secondary gas panel enclosures, are typically six-sided fully enclosed enclosures with access panels/doors on at least one side. These ventilated enclosures are designed to contain and remove hazardous gases from the work area in the event of a gas piping failure or leak. Gas panel enclosures are typically of two types, those requiring no access while gas systems are charged, and those that must be opened during processing while gas systems are charged. There is also a distinct difference in control specifications for those with pyrophorics or other flammables vs. other HPMs, specifically in the control of pocketing.

R16-6.2 Design Recommendations

R16-6.2.1 Compartmentalize potential leak points.

R16-6.2.2 Minimize the total size of the panel and its enclosure.

R16-6.2.3 Minimize size and number of openings.

R16-6.2.4 Minimize static pressure requirements of the enclosure; control has been shown to be achievable with –1.3 to –2.5 mm (–0.05 to –0.1 in.) w.g.

SEMI S2-0818E © SEMI 1991, 2018 124

R16-6.2.5 Design for sweep. Minimize the number and size of openings. Seal unnecessary openings (e.g., seams, utility holes).

R16-6.2.6 Where routinely used access doors are required:

Make the access door as small as practical.

Place the openings to the enclosure in the access door to minimize air flow requirements.

Provide baffles behind the door to direct leaks away from the door and openings.

Compartmentalize the enclosure so that access to one area does not affect air flow control in other areas.

R16-6.3 Control Specifications

R16-6.3.1 Exhaust volumes as low as 4 to 5 air changes per minute or less can be specified and meet the SEMI S2 criteria in § 23.5 if the design principles listed above are considered when designing equipment and enclosures.

R16-6.3.2 Where there is potential for chemical exposure during access which can be controlled by face velocity, the enclosure should also provide a minimum face velocity of 0.36 to 0.76 m/s (70 to 150 fpm) when open. Face velocity should not be relied upon to control emissions from a pressurized fitting.

R16-6.3.3 Enclosures for pyrophoric or flammable gases should be designed to ensure adequately uniform dilution (i.e., prevent ‘pocketing’) and to prevent accumulation of pyrophoric and flammable gases above 25% of their lower flammable limit. Uniform dilution can generally be verified through exhaust vapor visualization techniques. Ventilation flow rate should be adequate to maintain concentrations below 25% of the lower flammable limit for the gas with the lowest LFL that is used in the enclosure. This can generally be verified using engineering calculations to verify dilution, and vapor visualization to verify mixing.

R16-6.4 Recommended Measurement/Validation Method

R16-6.4.1 Preferred validation by tracer gas testing per Appendix 2 of SEMI S6.

R16-6.4.2 Additional confirmation by visualization check of air flow, mixing and sweep using smoke or vapor testing.

R16-6.4.3 Measurement of average face velocity at inlet(s), opening(s), or routinely used access doors. Measurements should be taken with a velometer or anemometer. For larger openings, multiple measurements are taken in a grid, at least 10 to 40 per square meter (1 to 4 per square foot) of open area. Useful equation: V = 4.043 (VP/d)0.5, where V = velocity in m/s, VP = velocity pressure in mm H2O, and d = density correction factor (unitless).

R16-7 Equipment Exhaust Ventilation Specifications and MeasurementsR16-7.1 Specifications for equipment exhaust should be provided by the supplier and define:

R16-7.1.1 The control specification or standard for the hood or enclosure (i.e., face velocity or capture velocity if applicable).

R16-7.1.2 The airflow in the duct required to maintain the control volume or flow required. Measurements should be made using the ACGIH pitot traverse method described below.

R16-7.1.3 The location where the pitot traverse measurement in the duct was made.

R16-7.1.4 Static pressure requirements.

R16-8 Duct Traverse MethodR16-8.1 Because the air flow in the cross-section of a duct is not uniform, it is necessary to obtain an average by measuring velocity pressure (VP) at points in a number of equal areas in the cross-section. The usual method is to make two traverses across the diameter of the duct at right angles to each other. Reading is taken at the center of annular rings of equal area. Whenever possible, the traverse should be made 7.5 duct diameters downstream and 3 diameters upstream from obstructions or directional changes such as an elbow, hood, branch entry, etc. Where measurements are made closer to disturbances, the results should be considered subject to some doubt and checked against a second location. If agreement within 10% of the two traverses is obtained, reasonable accuracy can be

125 SEMI S2-0818E © SEMI 1991, 2018

assumed, and the average of the two readings used. Where the variation exceeds 10%, a third location should be selected and the two air flows in the best agreement averaged and used. The use of a single centerline reading for obtaining average velocity is a very coarse approximation and is not recommended. If a traverse cannot be done, then the centerline duct velocity should be multiplied by 0.9 for a coarse estimate of actual average duct velocity. Center line duct velocity should not be used less than 5 duct diameters from an elbow, junction, hood opening, or other source of turbulence.

R16-8.2 For ducts 150 mm (6 in.) and smaller, at least 6 traverse points should be used. For round ducts larger than 150 mm (6 in.) diameter, at least 10 traverse points should be employed. For very large ducts with wide variation in velocity, 20 traverse points will increase the precision of the air flow measurement.

R16-8.3 For square or rectangular ducts, the procedure is to divide the cross-section into a number of equal rectangular areas and measure the velocity pressure at the center of each. The number of readings should not be less than 16. Enough readings should be made so the greatest distance between centers is less than 150 mm (6 in.).

R16-8.4 The following data are required:

R16-8.4.1 The area of the duct at the traverse location.

R16-8.4.2 Velocity pressure at each point in the traverse and/or average velocity and number of points measured.

R16-8.4.3 Temperature of the air stream at the time and location of the traverse.

R16-8.4.4 The velocity pressure readings obtained are converted to velocities, and the velocities (not the velocity pressures) are averaged. Useful equation: V = 4.043 (VP/d)0.5, where V = velocity in m/s, VP = velocity pressure in mm H2O, and d = density correction factor (unitless). Some monitoring instruments conduct this averaging internal to the instrument.

R16-8.5 Flow measurement taken at other than standard air temperatures should be corrected to standard conditions (i.e., 21C [70F], 760 mm [29.92 in.] Hg).

SEMI S2-0818E © SEMI 1991, 2018 126

RELATED INFORMATION 17 ADDITIONAL GUIDANCE FOR SAFETY FUNCTIONSNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures.

R17-1 PurposeR17-1.1 This Related Information provides information on the use of standards of safety functions as it is mentioned in the SEMI S2 § 11.6 related to the use of FECS.

R17-1.2 In the safety function section of SEMI S2, guidelines are given for the design and assessment of safety function. Because new, evolving technologies are used in the semiconductor and related industries, safety functions can be complex. This Related Information provides guidance on additional standards that might be useful for a safety function design and assessment. This Related Information explains how several different standards discuss the design of a safety function or safety related parts of control systems. This Related Information also provides a comparison among the definitions of reliability levels within several standards.

R17-1.3 A safety function as used in this Related Information is a function of the machine whose failure can result in immediate increase of the risks(s) [ISO 13849-1, IEC 62061, ISO 12100].

211:[212:] The term ‘safety function’ as used in SEMI S2 § 11 could be the entire safety related control system or safety related parts of control system as defined in the standards referenced in the following text, or it could be just a portion of these circuits, depending on the design approach chosen.

R17-2 LimitationsR17-2.1 This Related Information does not address calculations to determine the reliability of a safety function or safety related parts of control systems.

R17-3 Referenced Standards and DocumentsR17-3.1 SEMI Standards and Safety Guidelines

SEMI S10 — Safety Guideline for Risk Assessment and Risk Evaluation Process

R17-3.2 IEC Standards64

IEC 61496 — Safety of Machinery – Electro-Sensitive Protective Equipment

IEC 61508 (series) — Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems

IEC 62061 — Safety of Machinery – Functional Safety of Safety-Related Electrical, Electronic and Programmable Electronic Control Systems

R17-3.3 ISO Standards65

ISO 13849-1 — Safety of Machinery – Safety-Related Parts of Control Systems – Part 1: General Principles for Design

ISO 13849-2 — Safety of Machinery – Safety-Related Parts of Control Systems – Part 2: Validation

212:[213:] The ISO 13849 is the successor of EN 954: Safety of Machinery – Safety-Related Parts of Control Systems – Part 1: General Principles for Design. The hardware requirements of EN 954-1 were based on hardware architecture and fault tolerance. Safety function reliability was determined in a decision diagram using severity of possible harm, frequency of exposure, and the possibility of avoiding the harm. The definition of severity of possible harm, frequency of exposure, and possibility of avoiding the harm are identical to those in ISO 13849-1 (see § RR17-7 ).

ISO TR 23849 — Guidance on the Application of ISO 13849-1 and IEC 62061 in the Design of Safety Related Control Systems64 International Electrotechnical Commission, 3 rue de Varembé, Case Postale 131, CH-1211 Geneva 20, Switzerland; Telephone: +41.22.919.02.11, Fax: +41.22.919.03.00, http://www.iec.ch65 International Organization for Standardization, ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland; Telephone: +41.22.749.01.11, http://www.iso.org

127 SEMI S2-0818E © SEMI 1991, 2018

R17-3.4 Other Documents

Directive 94/9/EC of The European Parliament and the Council of 23 March 1994 on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres (commonly known as the ATEX directive)

R17-4 IntroductionR17-4.1 The term used for the circuit under analysis varies among the standards discussed in this Related Information. Some standards use ‘safety related part of control systems’, others use ‘safety function’, and the main term used in SEMI S2 is ‘safety function’. Throughout this Related Information, the term ‘safety function’ will be used for simplicity unless the specific term from a standard is needed for technical reasons.

R17-4.2 Some standards require different levels of reliability for a safety function depending on the risk it is mitigating. The risk level is evaluated from several factors like:

frequency people are expected to be exposed to potential harm,

the potential severity of the harm,

whether there is a possibility to notice the risk and avoid the harm.

R17-4.2.1 There are several standards that describe the reliability of safety functions (see Table RR2-1.1.1.1.1Table R2-1 ), and other standards (e.g., robot standards or machine safety standards) refer to these safety function reliability standards for the consideration of safety function designs and reliability assessment.

R17-4.3 This Related Information is limited to how these standards address the selection of a reliability level for a safety function. Information about how a safety function design can be assessed to see if the desired reliability was actually achieved is not addressed in this Related Information, but can be found in the referenced standards.

R17-4.4 Depending on the safety function standard, the criteria for the safety function may consider only harm to people, or it may also include damage to equipment or installations.

R17-5 SEMI S10 and Safety Function Reliability SelectionR17-5.1 SEMI S10 is used for risk identification, ranking and evaluation. When a risk is identified that a designer would like to mitigate, the SEMI S2 design strategy to eliminate hazards or control risks should be followed. If the mitigation is done by using a safety function, the referenced standards provide guidance that can be used as justification that the safety function design to adequately reduce the risk.

R17-5.2 After the mitigation plan has been designed, a new risk assessment is typically carried out to verify the risk has been sufficiently mitigated.

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#1 * Design requirements for safety functions are based on the risk after other risk mitigation has been implemented. The standards ISO 13849-1 and IEC 62061 are two documents that might be useful ways how to determine the design and

reliability level.Figure R17-1

Relation Between Risk Assessment (e.g., SEMI S10) and Safety Function Selection

R17-6 Selection of a Safety Function StandardR17-6.1 The standards listed in Table RR2-1.1.1.1.1 Table R2-1 have their own scope of application. Due to the many types of safety functions, not all of the standards listed may be applicable to a specific safety function.

Table R17-1 Application of Safety System Related Standards

Standard Typical Use Components/Designs Covered

ISO 13849-1: Safety of machinery – Safety-Related Parts of Control Systems

Calculation of the reliability of individual components and complete safety function

It applies to any type of technology and energy used (electrical, hydraulic, pneumatic, mechanical, and software)

IEC 62061: Safety of machinery – Functional Safety of Safety-Related Electrical, Electronic and Programmable Electronic Control Systems

Calculation of the reliability of complete safety functions

Electromechanical, control system

129 SEMI S2-0818E © SEMI 1991, 2018

Standard Typical Use Components/Designs Covered

IEC 61508 series Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems

Verification of a control system that uses softwareUsed for requirements of a software control system. Most of the time a safety PLC is approved based in this applications.

Programmable logic controller (PLC) controlled system

European ATEX directive: 94/9/EC Defines reliability levels for components that need to be used in explosive atmospheres

Components that need to be used in explosive atmospheres

R17-7 Safety Function Performance Level Based on ISO 13849-1R17-7.1 This Standard uses the term ‘safety related part of control systems’ to describe a safety function. ISO 13849-1 uses a risk estimation decision tree to identify a required performance level (PLr) for a safety function.

R17-7.1.1 Before the risk estimation can be done, it is important to clearly understand the hazard scenario which would exist if the planned safety function was not available.

R17-7.1.2 Risk reduction by other measures (e.g., mechanical guards, administrative controls, hazardous energy isolation, PPE, etc.) independent of the control system can be taken into account in determining PLr.

R17-7.1.3 There are 3 parameters related to the equipment hazards during operation, maintenance and service that contribute to the risk estimation and determination of PLr in ISO 13849-1.

Severity of the injury (S)

S1: Slight (normally reversible injury)

S2: Serious (normally irreversible injury or death)

Frequency or exposure to the hazard (F)

F1: Seldom-to-less-often and exposure time is short

F2: Frequent-to-continuous or exposure time is long

Possibility of avoiding hazard or limiting harm (P)

P1: Possible under specific conditions

P2: Scarcely possible

213:[214:] The original description for F1 and F2 in ISO 13849-1 uses and/or terminology for both F1 and F2 which could lead to conflict when choosing the frequency term. The F1 and F2 text provided is based upon feedback from ISO TC199 members and discussion forums.

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#1 The triangle used in Figure R17-2 is not related to the risk ranking of SEMI S10.Figure R17-1

ISO 13849-1 Decision Tree

R17-7.2 In ISO 13849-1 safety function reliability is expressed in terms of required performance levels (PLr) a, b, c, d and e, with increasing reliability. Once the appropriate required performance level is determined, it is used to specify the minimum reliability requirements for the safety function. This analysis is relevant not just for an electrical safety function, as well as pneumatic, hydraulic and mechanical safety functions.

R17-7.3 The initial estimation (per R17-7.1.3.1 Figure R17-1) of the required performance level for a safety function is the beginning of the total design process. According to ISO 13849-1, designers must also assess three things:

How will the structural layout of the control system be chosen?

Will the safety control system have any monitoring/fault detection?

How will the component reliability requirements be chosen/met?

R17-7.4 ISO 13849-1 provides four parameters that designers need for determining if the required performance level has been achieved. These parameters are:

R17-7.4.1 Control System Category — Classification of the safety architecture based on the structural arrangement of parts, fault detection and the reliability of the components selected (e.g., CAT B, CAT 1, CAT2, CAT 3 and CAT4).

R17-7.4.2 Mean Time to a Dangerous Failure (in years) [MTTFd] — The MTTFd is the average time in which a failure that would lead to a ‘dangerous situation’ occurs in the safety function circuit. The MTTF d has three possible values: Low (between 3 to 10 years), Medium (between 10 and 30 years), and High (more than 30 Years).

R17-7.4.3 Average Diagnostic Coverage (%) [DCavg] — The DCavg is the ratio of the rate of dangerous failures that can be detected in the safety function, compared to rate of all dangerous failures (both detectable and undetectable) in the safety function. It is determined by how frequently and accurately the system undergoes failure-diagnosis, and what actions are taken if a failure is detected. The DCavg has four levels of detection: None (<60%), Low (≥60% – <90%), Medium (≥90% – <99%), and High (≥99%).

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R17-7.4.4 Common Cause Failure (CCF) — CCF is an indicator of whether different items in the safety function can fail from a common event (where these failures are not consequences of each other). ISO 13849-1 uses a PASS/FAIL checklist to help the designer to determine if they have included considerations to prevent common failures. Having technical measures for avoiding CCF is relevant for the multi-channel safety function CAT 2, 3 and 4 architectures, but it is not relevant for single channels architectures CAT B and CAT 1.

R17-7.5 ISO 13849-1 then uses mathematical techniques with grouping to estimate the performance level achieved based on these four basic function design factors. A graphical presentation of the ISO 13849-1 design validation process is shown in Table RR17-8.2.1.1.1 Table R17-1 .

Figure R17-3Overview of ISO 13849-1 Design Validation Process

R17-7.6 The standard provides both a tabular (refer to Table RR17-7.6.1.1.1 Table R17-1 ) and graphical way to estimate the achieved PL of a safety function. A successful design occurs when the achieved PL is greater than or equal to required performance level (PLr). If this is not the case, then a design modification and re-evaluation of the achieved performance level is necessary.

Table R17-1 Simplified Relation Between PL and Category Levels

Simplified View of the PL that Can be Achieved for a Given Category, DCavg and MTTFd

Category (basic architecture) B 1 2 2 3 3 4Average Diagnostic coverage (DCavg)

None None Low Medium Low Medium High

Mean Time To dangerous Failure (MTTFd) in each channel

Low a Not covered a b b c Not covered

Medium b Not covered b c c d Not covered

High Not covered c c d d d e

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214:[215:] More detailed information about comparison between performance levels and the design parameters of the safety function can be found in ISO 13849-1.

R17-8 Functional Safety of Safety Related Electrical, Electronic and Programmable Electronic Control Systems Selection Based on IEC 62061R17-8.1 The IEC 62061 standard uses the terms ‘severity of harm’ (Se), and ‘class of probability of occurrence of harm’ (Cl) in assessing safety function reliability.

R17-8.2 Severity of harm, (Se), is divided in 4 levels, as is shown in Table RR17-8.2.1.1.1 Table R17-1 .

Table R17-1 Severity Levels (Se)

Severity level Consequence

1 Reversible: requiring first aid only.2 Reversible injury, including severe lacerations, stabbing, and severe bruises that require attention from a

medical practitioner.3 Irreversible injury such that it is possible to continue work after healing. Also including a severe, major, but

reversible injury, such as broken limbs.4 Irreversible injury such as death, or losing an eye or limb.

R17-8.2.2 Class of probability of occurrence of harm (Cl) is a function of:

Frequency and duration of the exposure of persons to a hazard (Fr), Table RR17-8.2.3.3.1 Table R17-1 ;

Probability of occurrence of a hazardous event arising from human and machine behavior (Pr), Table RR17-8.2.4.2.1 Table R17-1 ;

Probability of avoiding the risk or limiting the harm (Av), Table RR17-8.2.5.1.1 Table R17-1 .

R17-8.2.3 Frequency and Duration of the Exposure of Persons to the Hazard

R17-8.2.3.1 Frequency and duration of the exposure of persons to the hazard, (Fr), is based on how often persons are exposed, and the duration for which they are exposed. Table RR17-8.2.3.3.1 Table R17-1 provides the values of Fr for various frequencies and durations.

R17-8.2.3.2 The frequency of exposure is divided into 5 levels of time between exposures.

R17-8.2.3.3 The duration of exposure to the hazard is divided into 2 levels: less than 10 minutes per occurrence, and greater than or equal to 10 minutes per occurrence.

Table R17-1 Frequency and Duration of Exposure (Fr)

Frequency (time between exposures) Duration < 10 Min. Duration ≥ 10 min

≤1 time per hour 5 5<1 time per hour to >= 1 time per day 4 5

<1 time per day to >=1 time per 2 weeks 3 4<1 time per 2 weeks to >= 1 time per year 2 3

<1 year 1 2

R17-8.2.4 Probability of Occurrence of a Hazardous Event Arising from Human and Machine Behavior (Pr) — This factor is an estimation on the behavior of the machine and foreseeable characteristics of human behavior.

R17-8.2.4.1 The machine behavior will vary from very predictable to not predictable. Unexpected events cannot be discounted. Predictability of the behavior of component parts of the machine relevant to the hazard in different modes of use (e.g., normal operation, maintenance, fault finding) must also be considered.

133 SEMI S2-0818E © SEMI 1991, 2018

R17-8.2.4.2 Characteristics of human behavior must also be taken in account such as stress and lack of awareness. These characteristics are influenced by factors such as skills, training, experience and complexity of the machine.

215:[216:] It is recommended that supplier-expected skills and training for user personnel be stated in the documentation provided to the user.

Table R17-1 Probability Classification

Probability of Occurrence Probability of Occurrence Factor (Pr)

Very High 5Likely 4

Possible 3Rarely 2

Negligible 1

R17-8.2.5 Probability of Avoiding or Limiting the Harm (Av) — This factor can be estimated by taking into account aspects of the machine such as sudden, fast or slow appearance of the hazardous event, clearances to withdraw from the hazard, nature of the system (e.g., a cutting machine will have a sharp edge, a heating system will have hot surfaces), and the possibility of recognition of the hazard (e.g., electrical hazards can only be recognized by using a meter, noise hazards may only be apparent when a motor starts).

Table R17-1 Probability of Avoiding or Limiting Harm

Probability of Avoiding or Limiting Harm Probability of Avoiding or Limiting Harm Factor (Av)

Impossible 5Rarely 3

Probable 1

R17-8.2.6 The final probability rating, the class of probability of occurrence of harm (Cl), is the sum of frequency and duration (Fr), probability of occurrence (Pr), and possibility of avoidance (Av).

R17-8.2.7 C1 = Fr + Pr + Av

R17-8.2.8 These values are used to determine a safety integrity level (SIL) requirement for the safety function as shown in Table RR17-8.2.8.1.1 Table R17-1 .

Table R17-1 SIL Requirement

SeverityClass of Probability of Occurrence of Harm (Cl)

3–4 5–7 8–10 11–13 14–15

4 SIL 2 SIL 2 SIL 2 SIL 3 SIL 33 #1 SIL 1 SIL 2 SIL 32 #1 SIL 1 SIL 21 #1 SIL 1

#1 For these levels, other measures may be appropriate (e.g., performance level (PL) ‘a’ as per ISO 13849-1).

R17-8.3 The calculation of the actual SIL level of a proposed safety function is based on the architecture of the design and the reliability data of the chosen components. Details can be found in IEC 62061.

SEMI S2-0818E © SEMI 1991, 2018 134

R17-9 Other Standards and Regulations that Might be UsefulR17-9.1 The European legislation for Equipment Intended for Use in Potentially Explosive Atmospheres (ATEX) defines reliability levels for equipment which is intended to be used in areas with a potential explosion risk. The reliability levels are based on an assessment of substances that comprise the potentially explosive atmosphere and time the atmosphere is expected to be present. Details on the requirements can be found in the ATEX directive.

R17-9.2 The IEC 61508 series standards provide information and requirements if programmable logic controllers or logic devices are used to make up a safety function. It is recommended that a software dependent safety function be assessed and approved by a NRTL to this standard.

R17-9.3 ISO TR 23849 provides information on electro-sensitive protective equipment that might be used in a safety function (e.g., light curtains), and their relation with ISO 13849-1 and IEC 62061.

R17-10 Comparison Between the Different Reliability LevelsR17-10.1 IEC document, TR 62061-1, provides more information comparing ISO 13849-1 and IEC 62061, and provides an introduction to the calculation of reliability levels. One concept discussed is ‘PFH d’, an estimated data point (parameter) of a subsystem that takes into account the contribution of factors such as diagnostics, proof of test interval, resistance to common cause failure, and control system architecture (structure). Besides the Average Probability of a Dangerous Failure per Hour (PFHd); some additional estimations are necessary to determine an achieved performance level

Table R17-1 Relationship Between SIL’s and Performance Levels

Performance Level (PL) Average Probability of a Dangerous Failure per Hour (1/h); PFHd

Safety Integrity Level (SIL)

a 10−5 to < 10−4 Not definedb 3 × 10−6 to < 10−5 1c 10−6 to < 3 × 10−6 1d 10−7 to < 10−6 2e 10−8 to < 10−7 3

135 SEMI S2-0818E © SEMI 1991, 2018

RELATED INFORMATION 18 DESIGN CRITERIA FOR PLATFORMS, STEPS, AND LADDERSNOTICE: This Related Information is not an official part of SEMI S2 and was derived from the work of the Environmental Health & Safety Global Technical Committee. This Related Information was approved for publication by full letter ballot procedures on December 4, 2015.

R18-1 PurposeR18-1.1 This Related Information provides good engineering practices for the design of ladders, stair ladders, platform stands, platforms, stairs, guardrail systems and handrails.

R18-2 ScopeR18-2.1 The scope of this Related Information is ladders, stair ladders, platform stands, platforms, stairs, guardrail systems and handrails that are provided, by the supplier, as standalone pieces or integral to the equipment.

NOTICE: SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the Documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.

R18-3 Terminology216:[217:] These terms and their definitions are in addition to those in § 5 of SEMI S2.

R18-3.1 alternating tread stair ladder — stair ladder on which the treads are approximately one-half the width of the stair ladder and alternate in right and left alignment for the length of the stair ladder. (See R18-3.1.1.1 FigureR18-1.)

Figure R18-1 Example of Alternating Tread Stair Ladder

R18-3.2 dead load — the static force exerted on a structure or object.

R18-3.3 horizontal guardrail system — a guardrail system, such as those erected along the exposed sides and ends of platforms, in which the toprail, midrail, and toeboard are approximately horizontal.

R18-3.4 inclined guardrail system — a guardrail system, such as those erected along the exposed sides of stairs, in which the toprail, midrail, and toeboard are approximately parallel to the direction of travel, rather than being horizontal.

R18-3.5 live load — the force exerted on a structure or object as a consequence of its anticipated environment and normal use (e.g., load from personnel and transient materials such as tool boxes).

217:[218:] ‘Live load’ can be contrasted with ‘dead load’, which is essentially the non-variable load, exerted by materials and installation conditions of the structure.

R18-3.6 pitch — the angle between the plane passing through the front edges of consecutive steps or rungs and the horizontal surface. Pitch is defined mathematically by:

pitch = arctangent (rise/run) (R18-1)

SEMI S2-0818E © SEMI 1991, 2018 136

R18-3.7 rise — vertical distance between the treads of successive steps or rungs.

R18-3.8 run — horizontal distance between the front edges of successive steps or rungs.

R18-3.9 span — the usable width (right to left) of a step or rung perpendicular to the direction of travel.

R18-3.10 step or platform depth — the dimension of a step or platform, measured in the direction of travel (e.g., from front to back).

R18-3.11 test load — a load applied to demonstrate compliance with criteria.

R18-3.12 tread — the walking surface of a step.

R18-4 Materials of ConstructionR18-4.1 Selection of materials of construction should consider their intended use, such as during energized electrical work or with extreme temperatures.

R18-5 Walking or Working Surfaces, Including Platforms but Excluding Rungs and StepsR18-5.1 The design of walking or working surfaces should take into account the area required for, and loads presented by, personnel, tools and parts for tasks intended by the supplier.

218:[219:] There are two types of loading criteria specified in this Related Information; a distributed stress load such as ¶  RR18-5.4 which increases with an increasing surface area, and point stress load such as ¶ RR18-5.5 , which remains constant regardless of the overall walking or working surface area. The distributed load minimum addresses the general structural support for the walking or working surface; the point load minimum addresses the ability of the walking or working surface to support the foreseen localized loads.

R18-5.2 The tests outlined in this Related Information are to be performed by trained and qualified personnel who have knowledge of the techniques and the test apparatus described herein.

R18-5.3 Walking or working surfaces should be made of material either solid or with openings such that a 10 mm (0.38 in.) sphere cannot pass through for surfaces at a height of 3 meters or greater above another walking or working surface, and such that a 25 mm (1 in.) sphere cannot pass through regardless of height.

R18-5.4 Walking or working surfaces should be able to support at least 3.6 kN/m2 (75 lbf/ft2) evenly distributed over the entire surface.

R18-5.5 At locations where a person can stand or walk, the platform or walking or working surface should be able to support at least 1.3 kN (300 lbf.) concentrated load placed in each position that would cause maximum stress to one or more structural members. The concentrated load should be assumed to be on a 90 mm (3.5 in.) by 90 mm (3.5 in.) square.

R18-5.6 The height difference between the loaded and an adjoining, unloaded walking or working surface should not exceed 4 mm (0.16 in.).

R18-5.7 Conformance with ¶¶ RR18-5.4 and RR18-5.5 should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with ¶ RR18-5.5 , the following test method should be used.

219:[220:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-5.7.1 Preload walking or working surface for one minute with a 200 N (45 lbf.) load placed in each location described in ¶ RR18-5.7.2 . After removal of the preload, the position of the walking or working surface should be used as the origin for measurement in the next part of the test.

R18-5.7.2 Walking or working surface should withstand a test load of at least 1.3 kN (300 lbf.) concentrated load placed at each of:

137 SEMI S2-0818E © SEMI 1991, 2018

center of walking or working surface,

midpoint of the longest unsupported edge,

in a corner of a cantilevered surface, and

locations that would cause maximum stress

for one minute without failure or permanent deformation in excess of 1/200 of its span or 3 mm (0.12 in.) (whichever is larger) once the test load has been removed. The test load includes the rigid plate specified in ¶ RR18-5.7.3 . ‘Unsupported edge’ and the deformation criteria pertain to both individual plates and other components comprising the walking surface and the span of the continuous walking surface.

R18-5.7.3 Tests should be conducted using a rigid plate at least 12 mm (0.5 in.) thick by not more than 90 mm (3.5 in.) by 90 mm (3.5 in.) square. An elastomeric pad (rubber or polyurethane, with a Shore hardness of 80 ± 10 Durometer ‘A’) at least 12 mm (0.5 in.) thick, the same size as the rigid plate should be adhered to the plate’s underside.

R18-5.8 Means of Ascent and Descent — Walking or working surfaces should be specified or provided with a fixed or portable means of ascent and descent (e.g., steps, stairs, ladders).

EXCEPTION 1: Walking or working surface height is less than or equal to 230 mm (9 in.) above the adjacent walking or working surface;

EXCEPTION 2: Walking or working surface height is greater than 230 mm (9 in.) and not greater than 380 mm (15 in.) above the adjacent walking or working surface and the walking or working surface is intended by the supplier to be accessed (regardless of duration of use) by the same individual less than an average of once an hour, and no more than an average of 4 times, per 12 hours; or

EXCEPTION 3: Walking or working surface height is greater than 380 mm (15 in.) and not greater than 715 mm (28 in.) above the adjacent walking or working surface and the walking or working surface is intended by the supplier to be accessed (regardless of duration of use) by the same individual less than an average of 4 times per 12 hours, and hand coupling points are present to assist in ascending and descending.

220:[221:] The 380 mm (15 in.) height limit for walking or working surfaces without a means of ascent and descent are based upon biomechanical modeling using the 50th percentile male and not relying on any hand coupling. The height limit will accommodate the strength of the 25th percentile female.

221:[222:] The 715 mm (28 in.) limit is based upon the hip height of the 5th percentile Hong Kong female (bare footed).

222:[223:] There are generally two movements (up/down) each time a walking or working surface is accessed. The 4 times corresponds to 4 round trip movements within 12 hours.

R18-6 Guardrail SystemsR18-6.1 All Guardrail Systems

R18-6.1.1 Posts should be spaced not more than 2.4 m (8 ft.) center to center.

R18-6.1.2 Posts, toprails and midrails should be 38 mm (1.5 in.) in its minimum outside dimension.

223:[224:] There are no requirements for posts, toprails, and midrails to be round.

R18-6.1.3 The toprails of guardrail systems should also meet the criteria in § RR18-7.1 for handrails.

R18-6.1.4 Stairs ascending more than 500 mm (19.7 in.) above the adjacent floor or standing level, should have inclined guardrail systems on open sides where there is a lateral space exceeding 50 mm (2 in.). ( R18-6.1.4.1 FigureR18-1 illustrates the gap.)

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Gap

Figure R18-1 Lateral space between Stair and Wall

224:[225:] The 500 mm criterion is based upon ISO 14122-3 as to when guarding is required, but IBC section 1009.12 requires railings on all stairs. The 50 mm lateral spacing is based on the 5th percentile Chinese female foot breadth being 81 mm (3.2 in.).

R18-6.2 Toeboards

R18-6.2.1 Toeboards should be at least 100 mm (4 in.) high and should be placed not more than 6.35 mm (0.25 in.) above the platform, walking, or working surface.

225:[226:] ISO 14122-3 notes 10 mm (0.38 in.) as the gap between toeboard and walking surface.

R18-6.2.2 Inclined and horizontal guardrail systems should have toeboards if they would reduce the risk of falling objects striking personnel to Low or Very Low Risk (according to the risk assessment method of SEMI S10) in the area expected (during work tasks intended by the supplier) to be occupied.

226:[227:] ISO 14122-3 requires toeboards to be used if the gap is greater than 30mm (1.2 in.) from the adjacent structure.

R18-6.2.3 Toeboards should be made of material either solid or with openings such that a 10 mm (0.38 in.) sphere cannot pass through.

R18-6.3 Strength

R18-6.3.1 Guardrail systems should support, without permanent deformation exceeding 3 mm (0.12 in.), a load equal to 890 N (200 lbf.), applied in any direction at the least favorable points along the toprail. Conformance may be verified by applying loads upward, downward, and horizontally (perpendicular to the toprail, toward and away from the walking or working surface). The maximum loaded deflection should not exceed 30 mm (1.2 in.).

R18-6.3.2 Midrails or functionally equivalent structural members should be capable of withstanding, without permanent deformation exceeding 3 mm (0.12 in.), a force of 667 N (150 lbf.) applied in any downward or outward direction at any point along the midrail or functionally equivalent structural member. The maximum loaded deflection should not exceed 30 mm (1.2 in.).

R18-6.3.3 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing.

227:[228:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-6.4 Horizontal Guardrail Systems

R18-6.4.1 Toprails — the height of the top edge of toprail should be no less than 1.09 m (43 in.) and no more than 1.15 m (45 in.) above the walking or working surface. (See R18-6.4.2.1 Figure R18-1.)

139 SEMI S2-0818E © SEMI 1991, 2018

Midrail

Height of toprail measured from walking/working surface to top edge of railMinimum: 1090 mm (43 in.)Maximum: 1150 mm (45 in.)

Post

Toeboard

Vertical gap between horizontal membersMaximum: 500 mm (19.7 in.)

Toprail

Height of toeboardMinimum: 100 mm (4 in.)

Vertical gap between bottom of toeboard and walking/ standing surface Maximum: 6 mm (0.25 in.)

Minimum610 mm (24 in.) clearance

Minimum 508 mm (20 in.)

clearance

Minimum610 mm(24 in.)

clearance

Swinging gate

Swinginggate

Minimum 610 mm (24 in.) clearance

R18-6.4.2 Midrails — midrails or functionally equivalent structural members should be provided such that there is not a vertical gap more than 500 mm (19.7 in.) between elements of the guardrail system. (See R18-6.4.2.1 FigureR18-1.)

Figure R18-1 Horizontal Guardrail System

R18-6.4.3 Access Through Horizontal Guardrail Systems

R18-6.4.3.1 Where access through the guardrail system is required, the passage through it should either be provided with a self-closing gate or be offset so that a person cannot walk directly through the opening. A gate should have its toprail and midrail positioned at the same levels as those of the guardrail system.

R18-6.4.3.2 All gates should close against a firm stop to prevent users from pushing against them and falling through the opening. Gates are subject to the same strength criteria, when closed, as guardrail systems.

R18-6.4.3.3 Gates should be sized to provide a passage width not less than 610 mm (24 in.) when open. (See R18-6.4.3.6 Figure R18-1.)

R18-6.4.3.4 Operating forces of gates should not exceed 44.5 N (10 lbf.) as measured at the end of the gate farther away from the hinge.

R18-6.4.3.5 Operating forces of sliding gates should not exceed 31 N (7 lbf.).

R18-6.4.3.6 If swinging, gates should be designed to open onto the platform or floor. Obstruction of the area behind the gate, when the gate is opened, is acceptable as long as there is sufficient space available to allow personnel to pass through and to allow the gate to close. (See Figure R18-1, including dimensions.)

Figure R18-1 Gates in Horizontal Guardrail Systems

SEMI S2-0818E © SEMI 1991, 2018 140

Guardrail heightMinimum: 900 mm (35.5 in)Maximum: 1000 mm (39.4 in)

Gap between inclined membersMaximum 500 mm (19.7 in.)

Toprail

Midrail

R18-6.5 Inclined Guardrail Systems

R18-6.5.1 It is preferred that an inclined guardrail system be continuous for the full length of the incline. In the case of an interrupted inclined guardrail, the clear space between the two segments should not be less than 75 mm (3 in.) (to prevent hand traps), and not greater than 120 mm (4.7 in.).

R18-6.5.2 The height of an inclined guardrail should be 900 mm (35.5 in.) to 1m (39.4 in.) from the upper surface of the toprail to the surface of the tread in line with the leading edge of the tread. (See R18-6.5.2.1 Figure R18-1.)

228:[229:] ISO 14122-3 requires 900 to 1000 mm (35.5 to 39.4 in.) and OSHA regulations require 762 mm to 864 mm (30 to 34 in.) however, a review of letters of interpretation within OSHA’s website indicates that OSHA will accept compliance to published standards.

Figure R18-1 Inclined Guardrail System

R18-7 HandrailsR18-7.1 Size and Shape

R18-7.1.1 Each handrail should be mounted so as to offer no obstruction to a smooth surface along the top and both sides.

R18-7.1.2 The handrail should be of rounded or other section that will furnish an adequate handhold for anyone grasping it to avoid falling.

R18-7.1.3 The portions of handrails that are intended to be grasped should have a horizontal and vertical cross-sectional dimensions of not less than 33 mm (1.3 in.) or more than 56 mm (2.2 in.) each.

R18-7.1.4 Handrail ends should be arranged (e.g., turned toward a wall or downward) to reduce risks due to bodily impact to the end of the handrail.

R18-7.2 The length of the handrail should be clear of obstacles within a distance of 100 mm (3.9 in.), except on the underside of the handrail at its support points.

R18-7.3 The height should be 900 mm (35.5 in.) to 1 m (39.4 in.) from the upper surface to the surface of the tread in line with the leading edge of the tread.

R18-7.4 Strength

R18-7.4.1 Handrails should support, without permanent deformation exceeding 3 mm (0.12 in.), a load equal to 890 N (200 lbf.), applied in each direction at the least favorable point(s) along the rail. Conformance may be verified by applying loads upward, downward, and horizontally (perpendicular to the rail, toward and away from the walking or working surface). The maximum loaded deflection should not exceed 30 mm (1.2 in.).

R18-7.4.2 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing.

141 SEMI S2-0818E © SEMI 1991, 2018

229:[230:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-8 Stairs230:[231:] Stairs are defined as having a pitch of not more than 45 degrees. Means of ascent having a pitch of more than 45 degrees but not more than 75 degrees are stair ladders. Means of ascent having a pitch of more than 75 degrees but not more than 90 degrees are ladders.

R18-8.1 The span of each step should be at least 559 mm (22 in.).

R18-8.2 Tread surfaces should not have a slope greater than 6 mm in 300 mm (0.25 in. in 1 ft.) from horizontal.

R18-8.3 The uppermost step nearest to a landing should be level with the landing, or meet the criteria in ¶  RR18-8.8.

R18-8.3.1 If the uppermost step aligns level with the landing, its vertical misalignment to the top surface of the landing should not exceed 12 mm (0.5 in.).

R18-8.4 If the upper step is part of a landing, that portion of the landing that serves the function of the upper step should meet the step criteria with regard to structure and dimensions.

R18-8.5 The walking or working surfaces of all treads should be slip-resistant.

R18-8.6 The horizontal overlap of steps to steps and steps to landings should be at least 10 mm (0.38 in.). (See R18-8.6.1.1 Figure R18-1).

Figure R18-1 Stairs

R18-8.7 Vertical clearance above each stair tread to an overhead obstruction should be at least 2134 mm (7 ft.) measured from the leading edge of the tread.

R18-8.8 Rise and run should be uniform throughout any set of consecutive steps. The variation of the rise or of the run should not exceed 6 mm (0.25 in.).

R18-8.9 The rise should be a maximum of 229 mm (9.0 in.) and the run should be a minimum 229 mm (9.0 in.).

R18-8.10 Landings that are between sets of steps should be at least as wide as the narrower set of steps and have a minimum depth (dimension in the direction of travel) of 559 mm (22 in.).

231:[232:] OSHA 29 CFR 1910.20(g) requires 762 mm (30 in.) in the direction of travel.

SEMI S2-0818E © SEMI 1991, 2018 142

Applied Load12 mm (0.5 in.) Thick elastomeric pad

R18-8.11 Stairs should have a handrail on each side enclosed by a wall.

EXCEPTION: If each side is enclosed by a wall and the stairs are less than 1118 mm (44 in.) wide, one handrail is sufficient.

232:[233:] Stairs allow the user to descend while facing in the direction of travel.

R18-8.12 Strength

R18-8.12.1 The minimum rated live load of stairs should be the greater of 1.3 kN (300 lbf.) and the load intended by the supplier.

233:[234:] The load of 1.3 kN (300 lbf.) is based on the mass of a person being 113.4 kg (250 lb.) plus an additional 23 kg (50 lb.) for equipment.

R18-8.12.2 Stairs should be designed to support a minimum of 4 times the rated live load.

234:[235:] 29 CFR 1910.24 specifies stairs are to be constructed to carry a load five times the normal live load anticipated.

R18-8.12.3 The deflection of a step under the anticipated live load should not exceed 1/300 of the span or 6 mm (0.25 in.), whichever is less.

R18-8.12.4 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with §  RR18-8.12 , the following test method should be used.

235:[236:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-8.12.4.1 Preload step with a 200 N (45 lbf.) load placed on the center of the step for one minute. After removal of the preload, the position of the step should be used as the origin for measurement in the next part of the test.

R18-8.12.4.2 Stairs should withstand a test load of four times the rated load placed on the center of each step for one minute without failure or permanent deformation in excess of 1/200 of its span once the test load has been removed. The test load includes the rigid plate specified in ¶ RR18-8.12.4.3 .

EXCEPTION: All steps within a series do not need to be tested if engineering rationale can show that worst case(s) have been tested. The engineering rationale should be documented in the test report.

R18-8.12.4.3 Test should be conducted using a rigid plate at least 12 mm (0.5 in.) thick by not more than 90 mm (3.5 in.) by the step depth plus 25 mm (1 in.). An elastomeric pad (rubber or polyurethane, with a Shore hardness of 80 ± 10 Durometer ‘A’) at least 12 mm (0.5 in.) thick, the same size as the rigid plate should be adhered to the plate’s underside. (See Figure R18-1.)

Figure R18-1 Stairs Load Testing

143 SEMI S2-0818E © SEMI 1991, 2018

θx

Starting point of rail measured from floor to hand positionMaximum: 1000 mm(39.4 in.) above floor

236:[237:] The rigid plate is based on the standard loading block as defined in Figure 6 of ANSI A14.2-2000.

R18-8.12.4.4 Any damage or visible weakening of other components (siderails, legs, bracing, etc.) as a result of a test should constitute a failed test.

R18-9 Stair Ladders237:[238:] Stairs are defined as having a pitch of not more than 45 degrees. Means of ascent having a pitch of more than 45 degrees but not more than 75 degrees are stair ladders. Means of ascent having a pitch of more than 75 degrees but not more than 90 degrees are ladders.

R18-9.1 Stair ladders should have a run of not less than 76 mm (3 in.) nor more than 190 mm (7.5 in.) and a rise of not less than 190 mm (7.5 in.) nor more than 279 mm (11 in.).

238:[239:] Steps are preferred at pitches between 45 degrees and 60 degrees.

R18-9.2 Steps or rungs should be slip-resistant. It is recommended that steps or rungs be constructed of corrugated, serrated, knurled, textured or dimpled materials.

239:[240:] Surface treatments such as abrasion strips, (e.g., adhesive-backed sandpaper) are less desirable, as they tend to wear or become damaged more easily than integral means.

R18-9.3 Stair ladders reaching 500 mm (19.7 in.) or more above the floor should have handrails positioned where the distance from the line through the front edge of the steps on a stair ladder to the bottom of the handrail are as shown in Table RR18-9.3.1.1.1 Table R18-1 , with the handrail beginning at a vertical distance of no more than 1 m (39.4 in.) from the floor or walking surface. Interpolate between stated values for intermediate pitches. (See R18-9.3.1.1 Figure R18-1.)

Figure R18-1 Stair Ladder

Table R18-1 Distances from the Pitch-Line on a Stair Ladder to the Bottom of the Handrail

θ (degrees) X (linear dimension perpendicular to the pitch-line) (mm)

46° 625 ± 1050° 500 ± 1055° 375 ± 1060° 250 ± 1065° 200 ± 1070° 150 ± 1075° 100 ± 10

SEMI S2-0818E © SEMI 1991, 2018 144

R18-9.4 Each end of the stair ladder handrail should connect to the horizontal guardrail system (if present) at the top or bottom of the handrail. In the case of a gap, the clear space between the two segments should not be less than 75 mm (3 in.) (to prevent hand traps), and not greater than 120 mm (4.7 in.).

R18-9.5 For handrail size, shape, and strength use the criteria in § RR18-7 .

R18-9.6 The documentation provided to the user should instruct personnel to face stair ladders (except alternating tread stair ladders, see R18-9.6.1.1 Figure R18-1) while ascending and descending.

Figure R18-1 Descending an Alternating Tread Stair Ladder While Facing the Direction of Travel

R18-9.7 Strength

R18-9.7.1 The minimum rated live load of a stair ladder should be the greater of 1.3 kN (300 lbf.) and the intended load.

R18-9.7.2 Stair ladders should be designed to support a minimum of 4 times the rated live load.

R18-9.7.3 Live loads imposed on a stair ladder should be considered to be concentrated at such point or points as will cause maximum stress in the structural member being considered.

R18-9.7.4 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with § RR18-9.7 , the following test method should be used.

240:[241:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-9.7.4.1 Preload step with a 200 N (45 lbf.) load placed on the center of the step for one minute. After removal of the preload, the position of the step should be used as the origin for measurement in the next part of the test.

R18-9.7.4.2 Stair ladders should withstand a test load of four times the rated load placed on the center of each step for one minute without failure or permanent deformation in excess of 1/200 of its span once the test load has been removed. The test load includes the rigid plate specified in ¶ RR18-9.7.4.3 .

EXCEPTION: Not all steps within a series need to be tested if engineering rationale can show that worst case(s) have been tested. The engineering rationale should be documented in the test report.

145 SEMI S2-0818E © SEMI 1991, 2018

R18-9.7.4.3 Test should be conducted using a rigid plate at least 12 mm (0.5 in.) thick by not more than 90 mm (3.5 in.) by the step depth plus 25 mm (1 in.). An elastomeric pad (rubber or polyurethane, with a Shore hardness of 80 ± 10 Durometer ‘A’) at least 12 mm (0.5 in.) thick, the same size as the rigid plate should be adhered to the plate’s underside. (See R18-8.12.4.3 Figure R18-1.)

R18-9.7.4.4 Any damage or visible weakening of other components (siderails, legs, bracing, etc.) as a result of the test should constitute a failed test.

R18-10 Platform StandsR18-10.1 The steps or rungs of platform stands should be slip-resistant. It is recommended that steps or rungs be constructed of corrugated, serrated, knurled, textured or dimpled materials.

R18-10.2 Steps or rungs should be uniformly spaced with differences between the largest and smallest rise and between the largest and smallest run to be no greater than 6 mm (0.25 in.).

R18-10.3 It is preferred that the pitch not exceed 75°.

R18-10.4 Where the pitch of steps for platform stands is no more than 45°, the steps should conform to the criteria for stairs.

R18-10.5 Where the pitch of steps or rungs for platform stands is greater than 45° and not more than 75°, the steps or rungs should conform to the criteria for stair ladders.

R18-10.6 Where the pitch of steps or rungs for platform stands is greater than 75 degrees, the steps or rungs should conform to the criteria for ladders.

R18-10.7 Protection against overturning of the unit during use intended by the supplier should be provided.

241:[242:] This criterion is not intended to replace criteria in ¶ 18.3 .

R18-10.8 Platform stands where the walking or working surface extends beyond the stand’s supporting structure (is cantilevered) should be designed so that a 2× rated load can be applied downward no farther than 50 mm (2 in.) from each edge of the platform or step without overturning.

242:[243:] The general stability criteria (i.e., those that apply whether or not there is a cantilever) are contained in ¶  RR18-10.15.1 .

R18-10.9 Joints comprised of threaded fasteners should be designed to be vibration tolerant (e.g., using a lock-nut or thread locking compound).

R18-10.10 Platform stands with wheels or casters should be equipped with a system to stop horizontal movement while occupied.

R18-10.11 Each wheel or caster should be able to support four times its anticipated load.

R18-10.12 Each unit should be marked with:

Supplier’s or manufacturer’s name or logo,

Month and year of manufacture, and

Maximum rated live load

R18-10.13 Product documentation should include instructions regarding:

Visual inspection,

Proper use, and

Maintenance

R18-10.14 Strength

R18-10.14.1 The minimum rated live load of a platform stand should be the greater of 1.3 kN (300 lbf.) times the number of persons and the load intended by the supplier.

R18-10.14.2 All platform stands should be designed to support a minimum of 4 times the rated live load.

SEMI S2-0818E © SEMI 1991, 2018 146

R18-10.14.3 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with § RR18-10.14 , the following test method should be used.

243:[244:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-10.14.3.1 Preload step or rung with a 200 N (45 lbf.) load placed on the center of the step or rung for one minute. After removal of the preload, the position of the step or rung should be used as the origin for measurement in the next part of the test.

R18-10.14.3.2 Treads should withstand a test load of four times the rated load placed on the center of each step or rung for one minute without failure or permanent deformation in excess of 1/200 of its span once the test load has been removed. The test load includes the rigid plate specified in ¶ RR18-10.14.3.3 .

EXCEPTION: Not all steps or rungs within a series need to be tested if engineering rationale can show that worst case(s) have been tested. The engineering rationale should be documented in the test report.

R18-10.14.3.3 Test should be conducted using a rigid plate at least 12 mm (0.5 in.) thick by not more than 90 mm (3.5 in.) by the step depth plus 25 mm (1 in.). An elastomeric pad (rubber or polyurethane, with a Shore hardness of 80 ± 10 Durometer ‘A’) at least 12 mm (0.5 in.) thick, the same size as the rigid plate should be adhered to the plate’s underside. (See R18-8.12.4.3 Figure R18-1.)

244:[245:] The rigid plate is based on the standard loading block as defined in Figure 6 of ANSI A14.2-2000.

R18-10.14.3.4 Any damage or visible weakening of other components (siderails, legs, bracing, etc.) as a result of the test should constitute a failed test.

R18-10.15 Stability — Platform stands should be stable under all anticipated load conditions with their rated live load uniformly distributed on the top step or platform.

R18-10.15.1 Side Stability — With a load of 890 N (200 lbf.) evenly distributed on the top step or platform, platform stands should withstand a sideward horizontal force of not less than 98 N (22 lbf.) applied perpendicular to the side of the unit at the handrail or guardrail above the center of the top step or platform without the unit tipping over. For units without handrails or guardrails, the force should be applied to the top step or platform at its center.

R18-10.15.2 Rear Stability — This criterion is the same as for the side stability criterion except that a rearward horizontal force of 98 N (22 lbf.) applied perpendicular to the rear handrail or guardrail. For units without handrails or guardrail, the force should be applied to the top step or platform at its center.

R18-10.15.3 Conformance with stability criteria should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with ¶ RR18-10.15 , the following test method should be used.

245:[246:] SEMI S7 Related Information 2 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to review or validate such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-10.15.3.1 The test unit should be placed on a level surface with the movement prevention system engaged. Units with wheels or casters should be blocked to prevent movement.

R18-10.15.3.2 A load of 890 N (200 lbf.) should be evenly distributed on the top step or platform.

R18-10.15.3.3 The unit under test should be subjected to a sideward horizontal force of 98 N (22 lbf.) applied perpendicular to the handrail, guardrail, top step or platform as shown in R18-8.12.4.3 Figure R18-1.

147 SEMI S2-0818E © SEMI 1991, 2018

Rearward pull without handrail or guardrail

Rearward pull with handrail or guardrail

Sideward pull without handrail or guardrail

Sideward pull with handrail or guardrailApplied weight

R18-10.15.3.4 The unit under test should be subjected to a rearward horizontal force of 98 N (22 lbf.) applied perpendicular to the handrail, guardrail, top step or platform as shown in R18-8.12.4.3 Figure R18-1.

R18-10.15.3.5 The platform stand tipping over with a force of 98 N (22 lbf.) or less should constitute a failed test.

Figure R18-1 Stability Test Locations

R18-10.16 Dimensions

R18-10.16.1 The minimum width of the base of platform stands should be 508 mm (20 in.), or the width of the top step or platform, whichever is greater.

R18-10.16.2 The maximum work level height of a platform stand should not exceed four (4) times its minimum base dimension. The minimum base dimension may be considered to include outriggers or other structural members.

R18-10.16.3 The Platform of Platform Stands

R18-10.16.3.1 The uppermost flat surface of a platform should have a depth of not less than 241 mm (9.5 in.).

R18-10.16.3.2 The minimum width should be 508 mm (20 in.).

R18-10.16.3.3 Platforms intended by the supplier for use by more than one person at a time should have a depth of more than 813 mm (32 in.) or a surface area of more than 0.62 m2 (6.7 ft2).

R18-10.16.3.4 Platforms should allow work to be performed in orientations as intended by the supplier and meet the appropriate dimensional criteria within Appendix 1 of SEMI S8.

R18-11 Ladders246:[247:] Stairs are defined as having a pitch of not more than 45 degrees. Means of ascent having a pitch of more than 45 degrees but not more than 75 degrees are stair ladders. Means of ascent having a pitch of more than 75 degrees but not more than 90 degrees are ladders.

R18-11.1 All Ladders

R18-11.1.1 Rungs and steps of ladders should be spaced not less than 178 mm (7 in.) apart, nor more than 304.8 mm (12 in.) apart, as measured between consecutive treads of the rungs or steps and the spacing should be uniform throughout the length of the ladder. The variation of the spacing should not exceed 6 mm (0.25 in.).

R18-11.2 Rungs should have a horizontal cross-sectional dimension between 19 mm (0.75 in.) and 40 mm (1.5 in.).

R18-11.3 Steps of ladders should have a depth of not less than 76 mm (3 in.) nor more than 190 mm (7.5 in.).

247:[248:] Rungs are preferred.

R18-11.3.1 The steps or rungs of ladders should be slip-resistant. It is recommended that steps or rungs be constructed using corrugated, serrated, knurled, textured or dimpled materials.

R18-11.3.2 Each ladder should be marked with its maximum rated live load.

R18-11.3.3 The documents provided to the equipment user should include instructions for the ladder regarding:

SEMI S2-0818E © SEMI 1991, 2018 148

Visual inspection

Proper use

Maintenance

R18-11.3.4 Strength

R18-11.3.4.1 The minimum rated live load of a ladder should be the greater of 1.3 kN (300 lbf.) and the load intended by the supplier.

R18-11.3.4.2 Ladders should be designed to support a minimum of 4 times the rated live load.

R18-11.3.4.3 Live loads imposed by persons occupying a ladder should be considered to be concentrated at such point or points as will cause maximum stress in the structural member being considered.

R18-11.3.5 Conformance with strength criteria should be verified either by calculations performed by a qualified engineer or by testing. If testing is used to verify conformance with § RR18-11.3.4 , the following test method should be used.

248:[249:] SEMI S7 § 8 highlights qualifications of personnel capable of reviewing and validating calculations or test results. A person may be qualified to perform such calculations by:

education in mechanical, structural, civil or architectural engineering;

being licensed or certified as PE (USA), Chartered (UK), or Eur Ing (EU) or equivalent; or

experience in design, construction, and analysis of such structures.

R18-11.3.5.1 Preload step or rung with a 200 N (45 lbf.) load placed on the center of the step or rung for one minute. After removal of the preload, the position of the step or rung should be used as the origin for measurement in the next part of the test.

EXCEPTION: Not all steps or rungs within a series need to be tested if engineering rationale can show that worst case(s) have been tested. The engineering rationale should be documented in the test report.

R18-11.3.5.2 Ladders should withstand a test load of four times the rated load placed on the center of the each rung or step for one minute without failure or permanent deformation in excess of 1/200 of its span once the test load has been removed. The test load includes the rigid plate specified in ¶ RR18-11.3.5.3 .

R18-11.3.5.3 Test should be conducted using a rigid plate at least 12 mm (0.5 in.) thick by not more than 90 mm (3.5 in.) by 25 mm (1 in.) plus the contact depth of the step or rung. An elastomeric pad (rubber or polyurethane, with a Shore hardness of 80 ± 10 Durometer ‘A’) at least 12 mm (0.5 in.) thick, the same size as the rigid plate should be adhered to the plate’s underside. (See R18-8.12.4.3 Figure R18-1.)

R18-11.3.5.4 Any damage or visible weakening of other components (siderails, legs, bracing, etc.) as a result of the test should constitute a failed test.

R18-11.4 Additional Criteria for Fixed Ladders

R18-11.4.1 The minimum span for fixed ladders should be 406.4 mm (16 in.).

R18-11.4.2 The minimum perpendicular distance from the center line of the rungs to the nearest permanent object on the climbing side of the ladder should be 915 mm (36 in.) for a pitch of 76 degrees, and 762 mm (30 in.) for a pitch of 90 degrees, with minimum clearances for intermediate pitches varying between these two limits in proportion to the slope. (See R18-11.4.2.1 Figure R18-1.)

149 SEMI S2-0818E © SEMI 1991, 2018

90° degrees 76° degrees

915 mm (36 in.)762 mm (30 in.)

Rung spacing, measured tread surface to tread surfaceMinimum: 178 mm (7 in.)Maximum: 305 mm (12 in.) Minimum side clearance to any permanent obstruction:

381 mm (15 in.) measured from centerline of rungs to each side

Minimum clearance between ladder rails406 mm (16 in.)

Figure R18-1 Ladder Climbing Side Clearance

R18-11.4.3 A clear width of at least 381 mm (15 in.) should be provided each way from the center line of the ladder in the climbing space. (See R18-11.4.3.1 Figure R18-1.)

Figure R18-1 Ladder Clearances and Dimensions

R18-11.4.4 The distance from the center line of rungs or steps, to the nearest fixed obstruction in back of the ladder should be as shown in R18-11.4.4.1 Figure R18-1. Only the indicated clearances above, below or away from the obstruction are normative in this illustration. Other aspects of the illustration such as the obstruction type, rung cross-section, and ladder angle are only demonstrative and are not intended to limit the application of this paragraph.

Figure R18-1 Ladder Clearances Opposite to Climbing Side

SEMI S2-0818E © SEMI 1991, 2018 150

249:[250:] This criterion is related only to distances to objects that are in back of the ladder and not distances within the ladder unit.

R18-11.4.5 The step-across distance from the nearest edge of ladder to the nearest edge of equipment or structure should be not more than 305 mm (12 in.).

R18-11.4.6 If the platform is being accessed from a ladder, one rung of the ladder should be located at the level of the platform. (See R18-11.4.4.1 Figure R18-1.)

R18-11.4.7 The side rails of step-through or side-step ladder extensions should extend 1.1 m (3.5 ft.) above obstructions and platforms. For step-through ladder extensions, the rungs should be omitted from the extension and the ladder should have not less than 610 mm (24 in.), nor more than 762 mm (30 in.) clearance between rails. (See R18-11.4.7.1 Figure R18-1.)

Figure R18-1 Step-Through and Side Step Ladders

R18-11.4.8 Grab Bars

R18-11.4.9 The distance from the center line of the grab bars (individual handholds placed adjacent to or as an extension above ladders for the purpose of providing access beyond the limits of the ladder) to the nearest permanent object in back of the grab bars should be not less than 102 mm (4 in.). Grab bars should not protrude on the climbing side beyond the rails of the ladder which they serve.

R18-11.4.9.1 Horizontal grab bars should be spaced by a continuation of the rung spacing.

R18-11.4.9.2 Vertical grab bars should have the same spacing as the ladder side rails.

R18-11.4.9.3 Grab bar diameters should be 19 to 40 mm (0.75 to 1.5 in.).

R18-11.5 Additional Considerations for Portable Ladders

R18-11.5.1 The minimum span for portable ladders should be 304.8 mm (12 in.).

R18-11.5.2 Each portable ladder should also be marked with:

Supplier’s or manufacturer’s name or logo

Month and year of manufacture

151 SEMI S2-0818E © SEMI 1991, 2018

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SEMI S2-0818E © SEMI 1991, 2018 152 Copyright by SEMI®, 673 S. Milpitas Blvd., Milpitas, CA 95035. Reproduction of the contents in whole or in part is forbidden without express written consent of SEMI.