SEMIdownloads.semi.org/.../$FILE/5270.docx · Web viewDifferences in acoustic impedance at interfaces between different materials cause reflections; since air i.e., a flat free surface)

Background Statement for SEMI Draft Document 5270NEW STANDARD: GUIDE FOR MEASURING VOIDS IN BONDED WAFER STACKSNotice: This background statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this Document.

Notice: Recipients of this Document are invited to submit, with their comments, notification of any relevant patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this context, “patented technology” is defined as technology for which a patent has issued or has been applied for. In the latter case, only publicly available information on the contents of the patent application is to be provided.

BackgroundThis Guide will assist the user in selection and use of bond-void metrology tools based on their application. It also provides a protocol for performing bond-void measurements. 3DS-IC applications, with electrical connections between the wafers, are sensitive to significantly smaller voids than, for example, bonding processes such as are currently used for hermetically sealed MEMS packages.

This Guide is based on experimental results from round robin type experiment with 10 participating laboratories. Each laboratory measured bonded wafers with programmed voids of known size and depth. The wafer pairs, which were fabricated at SEMATECH using oxide bonding, were otherwise unpatterned. The participating laboratories represented a variety of metrology tools, each of which brought specific strengths and weaknesses to the problem of identifying and characterizing the voids. This Guide reports the void detection limits of each of these metrology tools and provides application recommendations with the goal of assisting producers and users in choosing the appropriate tool for their specific metrology needs.

The ballot results will be reviewed and adjudicated at the meetings indicated in the table below. Check www.semi.org/standards under Calendar of Events for the latest update.

Review and Adjudication InformationTask Force Review Committee Adjudication

Group: Inspection & Metrology TF North America 3DS-IC CommitteeDate: Tuesday, November 4, 2014 Tuesday, November 4, 2014Time & Timezone: 8:00 AM to 10:00 AM (U.S. Pacific Time) 3:00 PM to 5:00 PM (U.S. Pacific Time)Location: SEMI Headquarters

3081 Zanker RoadSEMI Headquarters3081 Zanker Road

City, State/Country: San Jose, California 95134 / USA San Jose, California 95134 / USALeader(s): Victor Vartanian (SEMATECH)

David Read (NIST)Richard Allen (NIST)Chris Moore (BayTech-Resor)Sesh Ramaswami (Applied Materials)Urmi Ray (Qualcomm)

Standards Staff: Paul Trio / [email protected]

Paul Trio / [email protected]

http://www.semi.org/standards

DRAFTDocument Number:

Date: 9/15/23

SEMI Draft Document 5270NEW STANDARD: GUIDE FOR MEASURING VOIDS IN BONDED WAFER STACKS1 Purpose1.1 This Guide will assist users in selection and use of bond-void metrology tools and a protocol for performing bond-void measurements based on their application. New bonding processes and applications are sensitive to significantly smaller voids than bonding processes currently used for 3DS-IC package sealing.

2 Scope2.1 This Guide is based on experimental data on 300-mm diameter silicon wafer pairs. The inspection and measurement tools covered include only commercial instruments available in the 2012-2014 time frame. The wafer bonding technique used was oxide bonding. The experimental data were provided by volunteer participants in this study and have not been independently verified.

2.2 This Guide covers the purpose and results of the experimental study. Detailed explanation of the principles of operation and construction of the instruments used is beyond the scope of this Guide.

2.3 The potential and actual effects of bond voids on the performance and reliability of fabricated devices are beyond the scope of this Guide.

2.4 The scope of this study does not extend to recommendations as to which techniques may be less or more appropriate for particular manufacturing processes, and no such recommendations are provided herein.

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 Guide is directly relevant only to the specific materials studied, at the time frame of the experimental study, and to the instruments used by the contributors. As a result of the specimen production process, the bond voids in the specimens used here did not have strong stress fields surrounding them, as might be the case for voids occurring in the manufacture of production devices. Therefore, the present specimens are not appropriate for evaluating measurement techniques that rely on local stress fields. The voids used here were located in arrays of same-sized and same-spaced voids. This may have created interference effects in the signals detected from these arrays. No foreign materials were introduced in the neighborhood of the voids, therefore the present specimens are not appropriate for evaluating techniques that rely on detecting the presence of materials different from silicon. The voids in the present study had flat surfaces parallel to the faces of the bonded wafers. Reflections of probes such as ultrasound or infrared light may be influenced by these flat surfaces.

4 Referenced Standards and Documents 4.1 SEMI Standards and Safety Guidelines

SEMI M1 — Specifications for Polished Single Crystal Silicon Wafers

SEMI 3D4 — Guide for Metrology for Measuring Thickness, Total Thickness Variation (TTV), Warp/Sori, and Flatness of Bonded Wafer Stacks

4.2 Other Documents

SEMI Auxiliary Information — Report on Round Robin Experiment on Bond Void Measurement

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

This is a Draft Document of the SEMI International Standards program. No material on this page is to be construed as an official or adopted Standard or Safety Guideline. Permission is granted to reproduce and/or distribute this document, in whole or in part, only within the scope of SEMI International Standards committee (document development) activity. All other reproduction and/or distribution without the prior written consent of SEMI is prohibited.

Page 1 Doc. jn l SEMI

Semiconductor Equipment and Materials International3081 Zanker RoadSan Jose, CA 95134-2127Phone: 408.943.6900, Fax: 408.943.7943


Date: 9/15/23

5 Terminology5.1 Abbreviations and Acronyms

5.1.1 BWP — bonded wafer pair

5.2 Definitions

5.2.1 cap wafer — standard wafer, oxidized, to be incorporated into a bonded wafer pair.

5.2.2 oxide bonding process – process of applying heat and pressure to a pair of oxidized wafers placed surface-to-surface, with no other material placed between them, to produce a mechanical bond between the wafers.

5.2.3 void wafer — wafer with recesses etched into the surface, to produce voids in the bond when incorporated in a bonded wafer pair. The void wafers used in this study were oxidized after etching the recesses.

6 Specimens6.1 Design of the Experimental Study — Participants were invited to inspect supplied BWP and measure the voids using the equipment of their choice. A report form requested the key data on presence, location, in-plane size, and severity or depth was provided. Bond voids were created by etching square wells in the Void Wafer of each BWP. Each participant received a set of four bonded-wafer pair (BWP) test vehicles to be inspected. Each test vehicle contained two standard thickness 300 mm silicon wafers bonded using an oxide bonding process. In each BWP the Cap Wafer was unpatterned; the Void Wafer was patterned with voids from 0.5 µm to 300 µm wide, and void thicknesses of 4-15 (specimens varied), 400, 900, and 1200 nm. Three different void patterns were used: dense, semi-dense, and isolated.

6.1.1 Artificial bond voids — The design of the artificial bond voids is indicated in Figures 1-3. Within the actual specimens, four different void depths, on separate wafers, were used.

Figure 1Schematic diagram showing the etched wells used to produce voids at the bonded interface between two

wafers





Date: 9/15/23

Figure 2Layout of the voids of different sizes and densities in die-sized arrays





Date: 9/15/23

Figure 3Details of the arrangement of artificial voids at different densities

6.1.2 Data reporting — The protocol supplied to each of the participants is attached to this document as Related Information 1. It describes the specimens and their markings. The guidance to the participants placed an emphasis on quantitative results, particularly how void detectability depended on void size and on capability for measurement of void sizes.

7 Principles of operation of Inspection and Metrology Tools Relevant to Bond Voids7.1 Ultrasonic Techniques — Ultrasonic inspection techniques have been adapted to survey the interface of a bonded wafer pair. In a technique called resonance ultrasonic inspection, vibrations in the 20 kHz to 100 kHz frequency range are induced in the bonded wafer pair. A second acoustic transducer monitors the frequency response. Differences in the frequency response between a void-free bonded pair and a bonded pair under inspection can indicate the presence of bond voids. In scanning acoustic microscopy, a single transducer both serves as the source of the signal and measures the reflected return signal. Differences in acoustic impedance at interfaces between different materials cause reflections; since air (i.e., a flat free surface) reflects 100% of the acoustic signal, the strongest reflected signals are generated by voids between wafers. The presence and size of voids can thus be determined. The propagation characteristics of ultrasonic sound depend strongly on the frequency of the sound waves, which is determined by the transducer that produces the signal. Lower frequencies propagate deeper into the wafer while higher frequencies can give better spatial resolution. The transducers used for acoustic microscopy typically have a resonant frequency somewhere between 5 MH and 500 MH. Since ultrasound does not propagate through air at any of the frequencies used for these inspections, a coupling fluid – typically deionized water – is used to interface the transducer and the wafer pair.

7.2 Infrared (IR) Techniques — A variety of techniques that utilize IR light have been developed for detection and characterization of voids, as silicon wafers are transparent to light with wavelengths longer than approximately 1 µm. Conventional IR microscopy instruments have a field of view much smaller than the full 300-mm diameter of a wafer. Full-wafer IR examination has also been applied. The IR instruments can be further split into those that identify inhomogeneities by direct measurement and those that use interferometry. IR microscopy can be used to measure the amount of light either transmitted or reflected by the bond interface; since voids tend to reflect a significant portion of the light, voids can be readily identified. As with all microscopes, a lower limit on resolution is around the order of the wavelength of the light source. Whole wafer IR uses transmitted light to capture an image of the wafer; it can be used to identify voids no smaller than approximately 50% of the size of a single pixel of the imaging system, which is typically on the order of 50 µm. Infrared interferometry can be used to create an image of





Date: 9/15/23

the interface between the BWP. An additional IR tool, the grey-field polariscope, captures the polarization of IR light transmitted by a bonded wafer pair. This tool has been reported to be useful for identifying voids between wafers. However, because the programmed voids used in this experiment do not produce stress between the wafers, and because observable polarization effects depend on stresses, this observation was not sensitive to the voids used in this experiment.

7.3 X-ray Technique — X-ray tomography has been considered as a possible technique for detecting and characterizing wafer bond voids. However, tomography depends on contrast between the different materials that make up the specimen. The silicon wafers used in this experiment are virtually transparent to x-rays and the voids were not distinguishable to a useful degree.

8 Results8.1 Qualitative Results — Techniques applied by some of the contributing laboratories were capable of producing qualitative results only. These included full wafer ultrasonic resonance and infrared interferometry.

8.1.1 Full wafer ultrasonic resonance — The contributing laboratory concluded that this technique indicated the presence of voids in the specimen wafers with 800 and 1200 nm deep voids.

8.1.2 Infrared Interferometry scanning — The contributing laboratory used an instrument with a spot size of 50 μm. Their experimental result was an image of the BWP interface showing the presence of voids.

Figure 4Result of Infrared Interferometry Scanning of one die on a bond void specimen wafer

8.2 Quantitative Results — Quantitative results for void detection, location, and size measurement were reported by several laboratories.

8.2.1 Infrared microscopy — Two laboratories applied infrared microscopy to measure the bond voids in the supplied specimen wafers.

8.2.1.1 Infrared microscopy, Lab 3 — Laboratory 3 examined all four wafers with an instrument setting of a pixel size of 8 μm and reported quantitative results for detection, location, and void size measurement. This technique produced clear images of many of the voids, as shown in Figure 5.





Date: 9/15/23

Figure 5Infrared microscopy image of 25 um wide, 1200 nm thick voids

8.2.1.1.1 Results for void detection by this technique are summarized in the following two tables.





Date: 9/15/23

Table 1 Results from Laboratory 3 on minimum void sizes for which presence was detected using 8 μm per pixel resolution, μm

Void thickness,

nm

Void densities

Isolated Semi-dense Dense

40 10 10 15400 2.5 5 15800 2.5 5 151200 2.5 5 5

Table 2 Results from Laboratory 3 on minimum void sizes for which presence was detected using 0.8 μm per pixel resolution, μm

Void thickness,

nm

Void densities


800 0.5 0.5 2.5

8.2.1.1.2 Void sizing results are shown in the following three plots.

Figure 6Plot showing Lab 3 void size measurement results for 1200 nm thick voids of three densities





Date: 9/15/23

Figure 7Plot showing Lab 3 results for void size measurements on isolated voids of two thicknesses

Figure 8Plot showing Lab 3 results for void size measurements on dense voids of two thicknesses





Date: 9/15/23

8.2.1.1.3 These results show that quantitative results for void sizing were obtained from 300 μm wide down to 50 μm wide voids for all the thicknesses cases.

8.2.1.2 Infrared microscopy, Lab 8 — Laboratory 8 measured their reported void sizes manually from their infrared microscopy images. A sample image of dense 2.5 μm wide voids with a nominal thickness of 150 nm is shown as Figure 9.

Figure 9Infrared microscopy image by Laboratory 8 showing dense 2.5 μm wide voids with a nominal thickness of 150

nm

8.2.1.1.4 Results for void detection by this technique are summarized in the following table.





Date: 9/15/23

Table 3 Results from Laboratory 8 on minimum void sizes for which presence was detected using a camera with resolution specified as 1024x1280 pixels with pixel size 5 μm

Void thickness,

nm

Void densities


40 1.0 1.0 2.5400 1.0 1.0 2.5800 1.0 1.0 2.51200 1.0 1.0 2.5

8.2.1.1.5 Void sizing results are shown in the following plot for semi-dense voids at the least and greatest thicknesses.

Figure 10Plot showing Lab 8 results for void size measurements on semi-dense voids of two thicknesses

NOTE: Manual measurement of void sizes from images was used

8.2.1.1.6 Laboratory 8 presented results for detection at all the supplied void thicknesses, and reported detection of voids from 300 μm wide down to 1 μm wide for isolated and semi-dense voids of all thicknesses, and from 300 μm wide down to 2.5 μm wide for dense voids. This laboratory presented quantitative results for sizing semi-dense voids at the maximum and minimum supplied void thicknesses, for void widths from 300 μm to 2.5 μm wide.





Date: 9/15/23

Laboratory 8 reported these results were obtained by manually measuring the void sizes from infrared microscopy images.

8.2.2 Ultrasonic microscopy — Multiple contributing laboratories applied ultrasonic microscopy to measure the bond voids in the supplied specimen wafers.

8.2.2.1 Ultrasonic microscopy, Lab 6 — Laboratory 6 used ultrasonic microscopy with a 190 MHz transducer. They provided results on detection of presence of voids and quantitative sizing results in the data sheets. The team tabulated their report on detection of presence in the following table. Their sizing results are shown in the following two plots.

Table 4 Results from Laboratory 6 on minimum void sizes for which presence was detected, μm

Void thickness,

nm

Void densities


40 10 10 15

1200 5 0.5 0.5

Figure 11Plot showing results of bond void size measurements on voids of two thicknesses





Date: 9/15/23

Figure 12Plot showing bond void size measurements by ultrasonic microscopy for 1200 nm thick voids of three

thicknesses

8.2.2.1.1 Quantitative results on void sizes were obtained from 300 μm wide down to 50 μm wide voids for all void densities at the largest and smallest thicknesses.

8.2.2.2 Ultrasonic microscopy, Lab 7 — Laboratory 7 used ultrasonic microscopy with a 200 MHz transducer. They provided results on detection of presence of voids and quantitative sizing results in the data sheets. The team tabulated their report on detection of presence in the following table. Their sizing results are shown in the following two plots.


Void thickness,

nm

Void densities


800 15 15 251200 10 10 15





Date: 9/15/23

Figure 13Ultrasonic microscopy results for bond void size measurement of isolated voids of two thicknesses

Figure 14Plot of measurements of bond void sizes for 1200 nm thick voids of three densities





Date: 9/15/23

8.2.2.2.1 Quantitative results on void sizes were obtained from 300 μm wide down to 75 μm wide voids for all void densities for the 1200 and 800 nm thick voids.

8.2.2.3 Ultrasonic microscopy, Lab 9 — Laboratory 9 used ultrasonic microscopy with a 200 MHz transducer. They provided results on detection of presence of voids and quantitative sizing results in the data sheets. The team tabulated their report on detection of presence in the following table. Their report indicated detection of the dense voids 40 nm thick “…as a whole, not individual…” for void sizes of 15 to 2.5 μm; they also indicated similar detection of dense void arrays for voids 400 nm thick for void sizes of 15 to 1.0 μm. Their sizing results are shown in the following two plots.


Void thickness,

nm

Void densities


40 10 10 25400 10 10 1

Figure 15Ultrasonic microscopy results for bond void size measurement of isolated, semi-dense-and dense voids 40 nm

thick





Date: 9/15/23

Figure 16Ultrasonic microscopy results for bond void size measurement of isolated, semi-dense-and dense voids 400 nm

thick

8.2.2.4 Ultrasonic microscopy, Lab 10 — Laboratory 10 used ultrasonic microscopy with a scan resolution of 20 μm. They provided results on detection of presence of voids and quantitative sizing results for the 400 nm thick voids at all three densities. The team tabulated their report on detection of presence of voids in the following table. Their sizing results are shown in the following plot. The void size results for the three densities were indistinguishable.


Void thickness,

nm

Void densities


400 25 50 50





Date: 9/15/23

Figure 17Plot of measurements of bond void sizes for 400 nm thick voids of three densities by Lab 10

8.2.2.4.1 Figure 18 compares acoustic microscope images of dies containing voids of the two extremes of thickness used here, 15 nm and 1200 nm. The images are very similar, indicating the insensitivity to void thickness of this particular technique. The images also show that the image intensity decreases markedly with decreasing void size.

Figure 18Acoustic microscope images of dies containing voids of the two extremes of thickness used here, 15 nm and

1200 nm.





Date: 9/15/23

9 Summary9.1 New bonding processes and applications are sensitive to significantly smaller voids than bonding processes currently used for 3DS-IC package sealing. This Guide compares detection, in bonded wafer pairs, of programmed voids in several oxide thicknesses. The results can be categorized into those that produced ‘qualitative detection’, meaning, they provided an indication of the presence of voids, and those that produced ‘quantitative detection’, meaning that they provided quantitatively accurate location and sizing of voids. Although imaging of the voids was not requested, several of the participants included images of the voids in their reports.

9.2 Summary for qualitative techniques — One participant applied ultrasonic resonance spectroscopy to the whole wafers. That participant’s report indicated that the presence of the 1200 and 800 nm thick voids was indicated in their application of this technique. Another participant used ultrasonic interferometry to produce an informative image of a bonded interface, showing multiple voids, but did not report the capability of deriving quantitative void sizes.

9.3 Summary for quantitative techniques — The participants that reported quantitative detection of bond voids all used either infrared microscopy (one laboratory) or ultrasonic microscopy (multiple laboratories). Section 8, above, gives plots, generated by the SEMI team from the raw data provided, of measured void sizes against designed sizes. Users of these techniques found little influence of void density and void thickness on their results. All were able to quantitatively detect the largest voids, and the results revealed a smaller void size cutoff ranging from 50 μm down to 2.5 μm in capability for accurate void size measurement. Specific results for each participant have been noted above. The variable of whether the diagonal or the side of the void was reported was omitted from the plotted results, by plotting the design size as the width where the width dimension was reported, and the diagonal where the diagonal dimension was reported.

NOTICE: Semiconductor Equipment and Materials International (SEMI) makes no warranties or representations as to the suitability of the Standards and Safety Guidelines set forth herein for any particular application. The determination of the suitability of the Standard or Safety Guideline is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant literature, respecting any materials or equipment mentioned herein. Standards and Safety Guidelines are subject to change without notice.

By publication of this Standard or Safety Guideline, SEMI takes no position respecting the validity of any patent rights or copyrights asserted in connection with any items mentioned in this Standard or Safety Guideline. Users of this Standard or Safety Guideline are expressly advised that determination of any such patent rights or copyrights, and the risk of infringement of such rights are entirely their own responsibility.





Date: 9/15/23

RELATED INFORMATION 1 PROTOCOL FOR THE EXPERIMENTAL STUDY, AS PROVIDED TO THE PARTICIPANTSNOTICE: This Related Information is not an official part of SEMI [designation number] and was derived from the work of the global [committee name] Technical Committee. This Related Information was approved for publication by full letter ballot procedures on [A&R approval date].

R1-1 Protocol (Version 1.9) for Cooperative Experimental Study on Detection of Voids in the Bondline between Bonded WafersR1-1.1 Thank you for your participation in the Cooperative Experimental Study on Detection of Voids in the Bondline between Bonded Wafers. This study is being conducted by the Bond Void Metrology Working Group under the SEMI 3DS-IC Inspection & Metrology Task Force. Its purpose is to document the capability of different wafer bond inspection systems on bonded wafer pairs representative of current fabrication practice.

R1-1.2 Protocol for participants in the experimental study

R1-1.2.1 Each participant is required to have

a. Access to a system capable of inspecting voids in the bond plane of 300-mm bonded silicon wafers, such as are used in 3-dimensional interconnect and in micro electro mechanical systems (MEMS). Liquid immersion is allowed.

b. This system must be capable of detection and sizing of small voids (diameters 300 micrometers and less) with depths of 4 nm to 1200 nm.

c. For recording and reporting the inspection data, the operator must have capability for data entry in spreadsheet files, and for transferring and writing same.

R1-1.2.2 Each participant will receive

a. A set of four bonded-wafer pair (BWP) test vehicles to be inspected, with a spreadsheet containing their lab’s wafer ID information. Each test vehicle contains two standard thickness 300 mm silicon wafers bonded using an oxide bonding process. In each BWP the Cap Wafer is unpatterned; the Void Wafer is patterned with voids from 0.5 µm to 300 µm wide, and depths ranging from 4 to 1200 nm. Each BWP contains two visible, machine readable alphanumeric codes; one each on the stack top and stack bottom, near the orientation notch. The BWP test vehicles will be in slots 11 – 14 of the FOSB as follows, with the patterned wafer facing down:

i. Slot 11: 1,200 nm deep voids

ii. Slot 12: 800 nm deep voids

iii. Slot 13: 400 nm deep voids

iv. Slot 14: 4-15 nm deep voids

An example of how the wafer shipping information should appear:

Company Void Depth (nm) Wafer ID 1 (Cap)- facing up

Wafer ID 2 (Void)- facing down Slot

Company A

1200 462A3I04SEA6 462A2N4BSEH1 11

800 462ASI08SED0 462A2J3ASEB7 12

400 46FGX031SJB1 462A556USEB7 13

4-15 462A3W85SEG5 462A5198SEG2 14





Date: 9/15/23

b. Spreadsheet file: to be filled in with experimental inspection data: Data Reporting Worksheet v1.8.xlsx.

c. Additional, descriptive information file (e.g., Navigating Bond Voids v 2.0.pptx).

d. This document (Protocol v. 1.9).

e. Cover sheet with a table listing the alphanumeric codes (top and bottom) for your specific wafer set.

f. Please note that electronic copies of the most current versions of all files will be posted on the 3ds-ic committee’s web site in the directory:

https://sites.google.com/a/semi.org/3dsic/3ds-ic-inspection-metrology-tf/5270-bond-void-interlaboratory-experiment

R1-1.2.3 Preliminary Steps

a. Copy the empty data file to a writeable drive. Rename it including unique, particular information such as the company name in the file name so we don’t receive multiple files with the same name.

b. Data from each specimen should be recorded on a separate page of the spreadsheet file.

i. Locate or create a page, fill in the specimen number, test date, operator name, inspection equipment type, and inspection equipment software version.

ii. Record instrument settings and data processing parameters used for final measurement, including, as applicable, adjustments for different specimens. This data can be appended to the spreadsheet or provided as a separate document. If it is more convenient to produce this in hard-copy format, please return these pages experiment coordinator as hard-copy or PDFs of scans.

R1-1.2.4 Setup

R1-1.2.4.1 Place the specimen into the inspection system with its orientation fiducial notch toward the operator and the specimen’s center near the center of the inspection system’s coordinate system (see Figure R1-1). Using the inspection system, locate the fiducial notch at approximately [x = 0 mm, y = -150 mm] from the center of the inspection system. Register the specimen origin at x = 0 mm and y = 150 mm from this fiducial notch.

Figure R1-1Wafer Coordinate System (after SEMI M20)







Date: 9/15/23

R1-1.2.4.2 The attached file describes how to identify the chip on the wafer to be measured; the spreadsheet file named Die_coordinate_worksheet.xls gives the locations of voids with particular sizes within the chips.

R1-1.2.5 Measurement Sequence

a. Position the bonded wafer pair to inspect the Default Die, whose center is located at coordinate position -2, 2.

i. Make certain that the wafer is placed in the tool with the “top” marking towards the sensor.

b. In that die, locate the 300 um bond void region, inspect and record the locations of

i. Isolated voids

ii. Location of one void in a Semi-dense region, and

iii. One void in a Dense region

c. Repeat this procedure within the Default Die for the 15 other bond void sizes from 275 um to 0.5 um.

d. If Default Die Inspection proves impractical, shift to one of the alternate die located at

i. 2,2 or

ii. 2,-2 or

iii. -2,-2

e. Complete die inspection using the above procedure.

R1-1.2.6 Measurement Data Reporting

a. For each nominal void size, three rows are provided in the spreadsheet (except for the 15 µm, 100 µm, and 300 µm voids – see item c). Fill these with data for the I, S, and D voids, as defined above. The procedure for each nominal void size, indicated in column B, is detailed as follows. We request that, if possible, all raw data be saved by the participating laboratory in the event of questions by the project team.

b. For the void size group being investigated, the operator should first attempt to find the isolated (I) void. The approximate locations of the (I) voids are listed in the file Die_coordinate_worksheet.xls. If this void is located, the operator will checkmark column F (Y) indicating yes to the question ‘Void detected?’ , in the spreadsheet corresponding to the specimen being inspected, in the appropriate cell. Otherwise the operator should checkmark column G (N). The operator will next record:

i. The location of the center of the isolated void in xy coordinates in columns H and I, using an origin and units that are appropriate for the equipment being used. If the units are not mm, the operator should so indicate in the worksheet.

ii. The size of the void as the largest diameter, in micrometers, in column N.

iii. The measured thickness of the void, in micrometers by preference, but in other units as appropriate if necessary for the system being used, in column O

Other information such as the area of the void, comments about its shape, or the filename of an image file can be entered in the spreadsheet, in columns T and beyond.

c. For three selected void sizes, 15 µm, 100 µm, and 300 µm diameters, the operator will repeat 5 times the size measurement of the isolated void simply by “pressing the button” of the inspection system to re-measure and re-record the void size of the captured data/image. These data are intended to assess “static repeatability” of the void size measurements.

d. Two additional rows for each nominal void size are provided in the spreadsheet. Fill these with data for the S, and D voids, as defined above. Enter the relevant data for the S or D void in the appropriate row, as indicated by an X in column C, D, or E. For both the S and D voids, the operator will attempt to locate and characterize a row of 3 adjacent voids. Because the die pattern contains arrays of multiple S and D voids, the operator may choose the 3 adjacent voids to be measured at his or her discretion. If such a row of voids is located, the operator will checkmark column F (Y) indicating yes to the question ‘Void (array) detected?’





Date: 9/15/23

in the spreadsheet corresponding to the specimen being inspected, in the appropriate cell. Otherwise the operator should checkmark column G (N).

i. The operator will record the location of the centers of the 3 selected voids in the appropriate row in columns H-M in the data recording sheet, in x,y coordinates using the notch as the origin and units in units of mm. If the metrology tool uses a different origin and/or measurement units, the native values will be stored and the data converted to mm and notch-origin.

ii. The operator will record the measured maximum diameter and the measured thickness, in micrometers, of the 3 selected voids in columns N-S.

iii. Other information such as the regularity of the array or the filename of an image file can be entered in the spreadsheet.

e. Repeat this procedure to acquire one complete set of data for all void sizes in one inspected die on all four specimens.

f. Repeat this procedure to acquire two additional complete sets of data for each void size on all four specimens on different days with the same operator.

R1-1.2.7 Contacts/Data reporting procedure

Questions about the samples, test structure design, and test protocol may be addressed to:

NameCompany/organizationStreet AddressCity, State, Zip Code

Email AddressTelephone Number

Provide the complete data file, containing data from 4 samples, via email to:

NameCompany/organizationStreet AddressCity, State, Zip Code

Email AddressTelephone Number

We ask that you retain and store the 4 samples for 12 months in case additional measurements are desired.

R1-1.2.8 Data analysis

R1-1.2.8.1 The data will be collated and analyzed statistically by the working group team. The results will be publicly announced at a date and location to be determined. Note that the specific results will be published without laboratory names associated with particular data sets.

Thank you for your participation in this cooperative study.





Date: 9/15/23

NOTICE: Semiconductor Equipment and Materials International (SEMI) makes no warranties or representations as to the suitability of the Standards and Safety Guidelines set forth herein for any particular application. The determination of the suitability of the Standard or Safety Guideline is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant literature, respecting any materials or equipment mentioned herein. Standards and Safety Guidelines are subject to change without notice.

By publication of this Standard or Safety Guideline, SEMI takes no position respecting the validity of any patent rights or copyrights asserted in connection with any items mentioned in this Standard or Safety Guideline. Users of this Standard or Safety Guideline are expressly advised that determination of any such patent rights or copyrights, and the risk of infringement of such rights are entirely their own responsibility.


