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Parylene coatings for enhanced reliability of electronics
Alan Hardy, Electronics Market Manager
SEMICON Taiwan2011
September 9, 2011
2SEMICON Taiwan2011 – September, 2011
Agenda
•Parylene
- History
- Overview of Specialty Coating Systems
- What is it?
- Why coat with it?
- How is it applied?
- Properties and benefits
- Industries and applications
•Adhesion Technologies
•Advanced Parylene Applications
•Conclusion
•Questions & Answers
SEMICON Taiwan2011 – September, 2011
3SEMICON Taiwan2011 – September, 2011
History of Parylene
• Dr. WM Gorham at Union Carbide Corporation (UCC) in late 1940’s
• Dr. Gorham announced the vapor deposition polymerization (VDP) process
– Coating process that bears his name patented in 1967
• Nova Tran Corp. purchased license agreement from UCC in 1971
– Made Parylene VDP a commercial success
• Union Carbide Corporation purchased Nova Tran Corp. in 1984
• Renamed Specialty Coating Systems in 1991
4SEMICON Taiwan2011 – September, 2011
SCS is the direct descendant of Union Carbide Corporation
– Unbroken transfer of technology and I.P. – Over 40 years of Parylene applications experience
SCS - the global leader in Parylene coating solutions
– Parylene variants, coating center locations, process development, coating technologies, equipment design, regulatory support
• SCS controls its own dimer source, quality and formulation
Specialty Coating Systems
5SEMICON Taiwan2011 – September, 2011
• 11 Worldwide Centers
– North America (5)– Costa Rica– United Kingdom– Ireland– Czech Republic– Japan– Singapore
• All coating centers use global Manufacturing Standard Procedures(MSPs) and quality standards
• Multiple locations enable SCS to react to changes in requirements, volume ramp-up or natural disasters
SCS Around the World
6SEMICON Taiwan2011 – September, 2011
• Dielectric strength
• Electrically conductive
• Antistatic
• Thermal insulation
• Heat dissipating
• Radiation shielding
• Moisture, chemical, fluid barrier
• Anti-stiction, low friction
• Seal or reduce microporosity
• Abrasion resistance
• Stabilizes components and structures
• Biostability and biocompatibility
Why Conformal Coat?
7SEMICON Taiwan2011 – September, 2011
Conformal Coating Material Considerations
• Freedom from byproducts
• Application temperatures
• Cure forces
• Conformability - uniformity
• Control of thickness
• Crevice penetration
• Regulatory/Quality compliance
• Biostability/Biocompatibility
• Properties of the coating
– Barrier capabilities
– Environmental stability
– Sterilizability and bio-acceptability
• Minimization of mechanical loading
8SEMICON Taiwan2011 – September, 2011
• A common generic name for a unique series of polymers based on p-Xylylene
POLY(PARA-XYLYLENE)
• A truly conformal, thin, optically clear, inert coating applied in a vacuum chamber at room temperature
• A non-line-of-sight coating that follows molecular level deposition process
• A chemically pure coating that does not use any catalysts or leachable materials
What is Parylene?
9SEMICON Taiwan2011 – September, 2011
Why Parylene?
• Completely conformal
• Ultra-thin and lightweight
• Free from pinholes and defects
• Moisture & chemical barrier
• High dielectric strength
• Chemical insolubility
• Dry film lubricity
• Particle immobilization
• Hydrophobicity
• Optically clear – colorless
• Biocompatible and biostable
• Chemically pure, inert and free of catalytic, plasticizer and solvent residues
• No outgassing
• No leachable ingredients
• No cure forces/stresses
• Environmentally friendly
• No thermal stresses during room temperature deposition
10SEMICON Taiwan2011 – September, 2011
Parylene Variants
11SEMICON Taiwan2011 – September, 2011
Parylene N
• High dielectric strength … 7,000 V@ 25 μm
• Maximum continuous service temperature … 60°C
• Short term (≤24 hrs.) maximum service temperature … 80°C
• Coefficient of Friction … 0.25
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations
Parylene Variants
12SEMICON Taiwan2011 – September, 2011
Parylene C
• High dielectric strength … 5,600 V@ 25μm
• Maximum continuous service temperature … 80°C
• Short term (≤24 hrs.) maximum service temperature … 100°C
• Excellent chemical resistance
• Lowest permeability to moisture and gases
• Coefficient of Friction … 0.29
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL− USP Class VI and ISO-10993 biological evaluations
Parylene Variants
13SEMICON Taiwan2011 – September, 2011
Parylene Variants
Parylene D
• High dielectric strength … 5,500 V@ 25μm
• Maximum continuous service temperature … 100°C
• Short term (≤24 hrs.) maximum service temperature … 120°C
• Lowest elongation
• Coefficient of Friction … 0.31
14SEMICON Taiwan2011 – September, 2011
Parylene Variants
Parylene HT®
• High dielectric strength … 5,400 V@ 25μm
• UV stable
• Lowest dielectric constant & dissipation factor
• Highest continuous service temperature … 350°C
• Short term (≤24 hrs.) maximum service temperature … 450°C
• Coefficient of Friction … 0.13
• Certifications
− IPC-CC-830, MIL-I-46058C and listed on the QPL
− USP Class VI and ISO-10993 biological evaluations
Parylene HT is a registered trademark of Specialty Coating Systems, Inc.
15SEMICON Taiwan2011 – September, 2011
Parylene Characteristics
Crevice Penetration
Parylene C ≈ 5 times the diameter
Parylene N ≈ 40 times the diameter
Parylene HT ≈ 50 times the diameterResults may vary depending on a number of factors
Acrylics – Spray or brush
Silicones – Spray or brush
Urethanes – Spray or brush
16TECH BRIEFS WEBINAR – DEC. 2010
Parylene Deposition Process
17SEMICON Taiwan2011 – September, 2011
Parylene Deposition
• Film grows one molecule at a time
• Coating thickness is controllable
- 500 angstroms to 75 microns
• Coating thickness is based on dimer quantity and chamber load
• Nominal coating rate is ≈ 5 microns/hour
18SEMICON Taiwan2011 – September, 2011
Parylene Deposition
• No cure forces
– No thermal reactions– No expansion or contraction
• Very high degree of penetration/conformity
– Under, inside, edges and sides
• No liquid phase
– No meniscus, no edge effects– Nothing to leach or outgas
Parylene Coating Liquid Coating
19SEMICON Taiwan2011 – September, 2011
SEMs courtesy of
E.E. Hui, UC Berkeley.
Parylene Characteristics
20SEMICON Taiwan2011 – September, 2011
Parylene Properties
21SEMICON Taiwan2011 – September, 2011
Parylene Electrical Properties
Properties Parylene N Parylene C Parylene HTDieletric Constant6 GHz 2.46 ‐ 2.54 3.06 ‐ 3.10 2.10 ‐ 2.15Dissipation Factor6 GHz 0.0002 ‐ 0.0010 0.0021 ‐ 0.0028 0.0015 ‐ 0.0020
Additional Data
22SEMICON Taiwan2011 – September, 2011
Improvement in Wire Lead & Bond Strength
• A bare 1 mil aluminum wire has a typical bond strength of 3 to 5.5 grams
• With a 1 mil coating of Parylene C over the wire, bond strength increases to between 60 and 70 grams
Wire-bond strength vs. Parylene C coating thickness on a hybrid-to-chip lead
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30
Pull Strength (in gram
s)
Coating Thickness (in microns)
Parylene C
23SEMICON Taiwan2011 – September, 2011
Parylene Barrier Properties
Water Vapor Transmission
Polymer N2 O2 CO2 H2
Parylene N 3 15.4 84.3 212.6
Parylene C 0.4 2.8 3 43.3
Parylene HT 4.8 23.5 95.4 –
Epoxy (ER) 1.6 4 3.1 43.3
Polyurethane (UR) 31.5 78.7 1,181 –
Silicone (SR) – 19,685 118,110 17,717
Gas Permeability at 25°C, (cc•mm)/(m2•day•atm)a
24SEMICON Taiwan2011 – September, 2011
Circuit boards after 144-hour salt fog test, in accordance with ASTM B117- (03).
Parylene Barrier Properties
Uncoated Coated
25SEMICON Taiwan2011 – September, 2011
Parylene Solvent Resistance
Chemical Tested Parylene N Parylene C Parylene HT
10% Nitric Acid, RT 0.1 0.1 0.0
10% Nitric Acid at 75oC 0.2 0.1 0.0
70% Nitric Acid, RT 0.2 0.2 0.0
70% Nitric Acid at 75oC Brittle 1.8 1.2
10% Sulfuric Acid, RT 0.1 0.3 0.0
10% Sulfuric Acid at 75oC 0.2 4.1 0.0
95-98% Sulfuric Acid, RT 0.2 0.4 0.0
95-98% Sulfuric Acid at 75oC 5.3 5.1 2.8
% Swelling
26SEMICON Taiwan2011 – September, 2011
Parylene Properties
0
1
2
3
4
Effe
ctiv
enes
s Ra
ting
Parylene N Parylene C Parylene HT Filter Cotton Duck
Test Samples
7 days14 days21 days28 days
Rating: 0 = None1= Traces of growth (less than 10%)2= Light growth (10-30%)3= Medium growth (30-60%)4= Heavy growth (60% to complete
coverage)
Test Method: ASTM G-21
Microorganism Resistance
Tested in accordance with Mil-STD 202, Method 302, test condition B (Temp: 650C, RH: 90-96%)
Moisture Resistance
27SEMICON Taiwan2011 – September, 2011
0
2
4
6
8
10
12
0 100 250 500 1000 1250 1500 2000
Visua
l color, cha
lk, crack ra
ting
[Scale: 0
‐Ve
ry poo
r, 10
‐Excellent]
UV exposure time (hrs)
Parylene C
Parylene HT
Parylene films were exposed to radiation from a bank of fluorescent lamps using the following test parameters:
- Device used: QUV - Type of test: Accelerated weathering- Test method: ASTM 154 - Irradiance: 0.77 Watts per square meter - Source: UVA 340 lamp
UV Stability
28SEMICON Taiwan2011 – September, 2011
Agenda
•Parylene
- History
- Overview of Specialty Coating Systems
- What is it?
- Why coat with it?
- How is it applied?
- Properties and benefits
- Industries and applications
•Adhesion Technologies
•Advanced Parylene Applications
•Conclusion
•Questions & Answers
29SEMICON Taiwan2011 – September, 2011
Adhesion Considerations
• Adhesion effects all types of applications
− Aerospace− Automotive− Electronics− Medical− Military
• Properties impacted by poor adhesion
− Electrical insulation− Chemical resistance− Corrosion protection− Environmental stress protection − Moisture resistance
30SEMICON Taiwan2011 – September, 2011
• Physical and chemical nature of substrate
• Solder masks
• Cleanliness of substrate
– Manufacturing and human residues
– Particle contamination
Factors Affecting Adhesion
Particle was not removed before Parylene coating and is now “captured”
31SEMICON Taiwan2011 – September, 2011
• Mode of coating - solution, vapor, plasma
• Cure forces
• Stresses in the coating
• Nature of coating material and coating formulation
• Primer and adhesion promotion
– Chemical – Plasma– Abrasion
Factors Affecting Adhesion
32SEMICON Taiwan2011 – September, 2011
Corrosion of a PCB
Delamination, chipping
Blister
Adhesion Issues
33SEMICON Taiwan2011 – September, 2011
Failed assembly with spots of poor adhesion Good assembly with strong adhesion (no spots)
Adhesion Issues
34SEMICON Taiwan2011 – September, 2011
AdPro Plus®
Chemical compound applied to a variety of metallic and plastic substrates (e.g., Stainless Steel, Cobalt-Chromium, Copper, Gold, Iridium, Nitinol, Platinum, Solder, Tin, Titanium, Tungsten, Aluminum, Nickel, Chromium, Brass, Polycarbonate, etc.) as a tie layer prior to the application of Parylene coating.
AdPro Poly®
Chemical compound applied to a variety of polymeric substrates (e.g., Polyimide, Epoxy, Acrylic, EPDM, etc.) as a tie layer prior to the application of Parylene coating.
AdPro Plus and AdPro Poly are a registered trademarks of Specialty Coating Systems, Inc.
Latest Developments in Adhesion Promotion Technologies
35SEMICON Taiwan2011 – September, 2011
Adhesion Promotion Technologies
0
1
2
3
4
5
Stainless Steel(Mirror like finish
#8), 24 hrs@50%RH
Stainless Steel(Mirror like finish
#8), 48 hrs@50%RH
Stainless Steel(Mirror like finish#8), Autoclave125C‐1 hr
Titanium AlloyGrade 5 (MilFinish), 24 hrs@50%RH
Titanium AlloyGrade 5 (MilFinish), 50 hrs@50%RH
Titanium AlloyGrade 5 (Mil
Finish), Autoclave125C‐1 hr
1
2.2
0
4.7 4.7
0
4.8 4.8 4.8 4.8 4.8 4.8
Silane A‐174 AdPro Plus
ASTM D 335
9‐2, M
etho
dB (0=P
oor, 5=Excellent)
36SEMICON Taiwan2011 – September, 2011
Adhesion Promotion Technologies
0
1
2
3
4
5
24 hrs @50%RH Autoclave 125C‐1 hr
0 0
1.9
3.2
4.9 4.9
Silane A‐174 AdPro Plus® AdPro Poly®
ASTM D 335
9‐2, M
etho
dB (0=P
oor, 5=Excellent)
Polyimide (Kapton) Substrate
DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.
37SEMICON Taiwan2011 – September, 2011
• AdPro Plus … solves adhesion challenges for difficult metallic and plastic substrates
• AdPro Poly … a new system that solves adhesion challenges for Polyimide substrates
• Both enhance the reliability of miniaturized and advanced components in all markets
Courtesy of DuPont.
Adhesion Promotion Technologies
DuPont™ and Kapton® are trademarks or registered trademarks of E.I. du Pont de Nemours and Company.
38SEMICON Taiwan2011 – September, 2011
Industries and Applications
39SEMICON Taiwan2011 – September, 2011
Mass air temperature and pressure sensors
Emission sensors
Tire Pressure Monitoring Systems (TPMS)
Diesel fuel heaters
O-rings, seals and engine gaskets
Fuel cell and hybrid electronic systems
Engine electronics
MEMS sensors
Automotive Coating Applications
40SEMICON Taiwan2011 – September, 2011
Wind power
Solar/photovoltaic
Energy harvesting
Hydropower
Geothermal
Renewable Energy Coating Applications
41SEMICON Taiwan2011 – September, 2011
Cardiac assist devices and components
− ICDs, pacemakers, VADs
Drug delivery devices
− Stents, inhalers (MDI, DPI, nasal)
Cochlear and intraocular implants
Catheters
Neurostimulators
Gastric balloons and cuffs
Endotracheal tubes
Laboratory devices
Printed circuit boards
Medical Device Coating Applications
42SEMICON Taiwan2011 – September, 2011
Military/Commercial
MEMS
Sensors
Circuit card assemblies
Motor components
Power supplies
Backplanes
Elastomeric parts
Aerospace
Spacecraft and satellite electronics
Cameras and assemblies
International Space Station remote arm components
Space Shuttle and International Space Station lab equipment
Military/Aerospace Coating Applications
43SEMICON Taiwan2011 – September, 2011
• Video displays
• Electronic billboards
• Marine lighting
• Transportation signage
• Outdoor illumination
• Vehicle lighting
• Commercial refrigeration
• Aviation lighting
LED Coating Applications
44SEMICON Taiwan2011 – September, 2011
• Printed circuit boards
• MEMS wafers
• Probes / pins
• Rotors / stators
• Components
– Metal– Brackets
• Cables
• Ferrite cores
Electronics Coating Applications
45SEMICON Taiwan2011 – September, 2011
Chip integration onto flexible Parylene electrodes
Images courtesy of Dr. Y. C. Tai, Caltech.
Advanced Parylene Applications
Parylene/Platinum retinal implant electrodes
46SEMICON Taiwan2011 – September, 2011
Parylene Etching
Anisotropic profile of 55 µ Parylene
Anisotropic profile of 10 µ Parylene
ICP etch recipes for low temperature (5ºC) Parylene etching
Reference: A HIGH ASPECT RATIO, FLEXIBLE, TRANSPARENT AND LOW-COST PARYLENE-C SHADOW MASK TECHNOLOGY FOR MICROPATTERNING APPLICATIONSBy: S. Selvarasah1, S. H. Chao, C.-L. Chen, D. Mao, J. Hopwood, S. Ryley, S. Sridhar, A. Khademhosseini, A. Busnaina, and M. R. Dokmeci, Shadow Mask Transducers 2007
Etching Method ParylenePlasma (200 mT, 400W) 0.19 µm/min
RIE (100 sccm, 200mT, 400W) 0.56µm/min
DRIE (60 sccm, 23mT, 800W) 0.77µm/min
47SEMICON Taiwan2011 – September, 2011
Conclusion
Parylene ultra-thin conformal coatings are being used more than ever to protect devices and components and enhance the reliability of today’s and tomorrow’s innovative technologies.
• Ultra-thin and conformal• Complete encapsulation• No liquid phase• No cure forces• Excellent moisture, chemical and
electrical properties • Low coefficient of friction• Exceptional thermal stability• Superior UV stability• Biocompatible and biostable
48SEMICON Taiwan2011 – September, 2011
Thank you for attending
49SEMICON Taiwan2011 – September, 2011
Specialty Coating Systems
• Contacts
– Mr. Hoon Keat, SCS, SingaporeTel: 65. 6862. 8687; Email: [email protected]
– Mr. Alan Hardy, SCS, Indianapolis, USA Tel: 317. 244. 1200 x 261; Email: [email protected]
Visit Booth 3040 for more information onParylene and Specialty Coating Systems