ASTM F1269-13(2018)
(Test Method)Standard Test Methods for Destructive Shear Testing of Ball Bonds (Withdrawn 2023)
Standard Test Methods for Destructive Shear Testing of Ball Bonds (Withdrawn 2023)
SIGNIFICANCE AND USE
5.1 Failure of microelectronic devices is often due to the failure of an interconnection bond. The most common type of interconnection bond is the thermosonic gold or copper wire bond. A very important element of this interconnection is the first bond or ball bond. These test methods can assist in maintaining control of the process for making ball bonds. They can be used to distinguish between weak and nonadherent ball bonds, of both, and bonds that are acceptably strong.
5.2 These test methods are appropriate for on-line use in process control, for process development, for purchase specifications, and for research in support of improved yield and reliability. Since the ball shearing method tests only the first bond in a microelectronic wire bond interconnection system, it must be used in a complementary fashion5 ,6 with the wire bond pull test.3
SCOPE
1.1 These test methods cover tests to determine the shear strength of a series of ball bonds made by either thermosonic or thermal compression techniques using either gold or copper wires.
Note 1: Common usage at the present time considers the term “ball bond'' to include the enlarged spheriodal or nailhead portion of the wire, (produced by the flameoff/spark [EFO] and first bonding operation in the thermosonic [or thermal compression] process), and the ball bond-bonding pad interfacial-attachment area or weld interface.
1.2 These test methods cover ball bonds made with small diameter (from 18 to 76-μm (0.0007 to 0.003-in.)) gold or copper wire of the type used in integrated circuits and hybrid microelectronic assemblies, system on a chip, and so forth.
1.3 These test methods can be used only when the ball height and diameter are large enough and adjacent interfering structures are far enough away to allow suitable placement and clearance (above the bonding pad and between adjacent bonds) of the shear test ram.
1.4 These test methods are destructive. They are appropriate for use in process development or, with a proper sampling plan, for process control or quality assurance.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
WITHDRAWN RATIONALE
These test methods covered tests to determine the shear strength of a series of ball bonds made by either thermosonic or thermal compression techniques using either gold or copper wires.
Formerly under the jurisdiction of F01 on Electronics, these test methods were withdrawn in November 2023. This standard is being withdrawn without replacement because Committee F01 was disbanded.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F1269 − 13 (Reapproved 2018)
Standard Test Methods for
Destructive Shear Testing of Ball Bonds
This standard is issued under the fixed designation F1269; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 These test methods cover tests to determine the shear 2.1 ASTM Standards:
strength of a series of ball bonds made by either thermosonic F458PracticeforNondestructivePullTestingofWireBonds
or thermal compression techniques using either gold or copper F459Test Methods for Measuring Pull Strength of Micro-
wires. electronic Wire Bonds
2.2 NIST Documents:
NOTE 1—Common usage at the present time considers the term “ball
bond’’ to include the enlarged spheriodal or nailhead portion of the wire, NBS Handbook 105-1Specification and Tolerances for Ref-
(produced by the flameoff/spark [EFO] and first bonding operation in the
erence Standards and Field Standards, Weights and Mea-
thermosonic [or thermal compression] process), and the ball bond-
sures
bonding pad interfacial-attachment area or weld interface.
IOLM Class M2-Circular 547-1 Precision Laboratory Stan-
1.2 These test methods cover ball bonds made with small
dards of Mass and Laboratory Weights
diameter (from 18 to 76-µm (0.0007 to 0.003-in.)) gold or
2.3 Military Standard:
copper wire of the type used in integrated circuits and hybrid
MIL-STD 883,Method2010
microelectronic assemblies, system on a chip, and so forth.
1.3 These test methods can be used only when the ball
3. Terminology
height and diameter are large enough and adjacent interfering
3.1 Definitions of Terms Specific to This Standard:
structuresarefarenoughawaytoallowsuitableplacementand
3.1.1 ball lift—a separation of the ball bond at the bonding
clearance(abovethebondingpadandbetweenadjacentbonds)
pad interface with little or no residual (less than 25% of the
of the shear test ram.
bond deformation area) ball metallization remaining on the
1.4 Thesetestmethodsaredestructive.Theyareappropriate
bonding pad (that remains essentially intact). In the case of
foruseinprocessdevelopmentor,withapropersamplingplan,
gold ball bonds on aluminum pad metallization, a ball lift is
for process control or quality assurance.
defined as a separation of the ball bond at the bonding pad
interface with little or no intermetallic formation either present
1.5 The values stated in SI units are to be regarded as the
or remaining (area of intermetallic less than 25% of the bond
standard. The values given in parentheses are for information
deformation area).
only.
3.1.1.1 Discussion—Intermetallic refers to the aluminum
1.6 This standard does not purport to address all of the
gold alloy formed at the ball bond pad metallization interfacial
safety concerns, if any, associated with its use. It is the
area where a gold ball bond is attached to an aluminum pad
responsibility of the user of this standard to establish appro-
metallization. If the wire/ball is of copper, then the aluminum
priate safety, health, and environmental practices and deter-
intermetallic is normally much thinner and may not be opti-
mine the applicability of regulatory limitations prior to use.
cally observable.
1.7 This international standard was developed in accor-
3.1.2 ball shear (weld interface separation)— an appre-
dance with internationally recognized principles on standard-
ciable intermetallic (in the case of the aluminum-gold system)
ization established in the Decision on Principles for the
and ball metallization, or both, (in the case of the gold-to-gold
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
These test methods are under the jurisdiction of ASTM Committee F01 on Standards volume information, refer to the standard’s Document Summary page on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic the ASTM website.
Materials, Wire Bonding, and Flip Chip. Available from the National Technical Information Service, 5285 Port Royal
Current edition approved March 1, 2018. Published April 2018. Originally Rd., Springfield, VA 22161.
approved in 1989. Last previous edition approved in 2013 as F1269–13. DOI: AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
10.1520/F1269-13R18. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1269 − 13 (2018)
system) remains on the bonding pad (area of remaining metal specifications, and for research in support of improved yield
or intermetallic greater than 25% of the bond deformation and reliability. Since the ball shearing method tests only the
area). first bond in a microelectronic wire bond interconnection
5,6
system,itmustbeusedinacomplementaryfashion withthe
3.1.3 bonding pad lift (substrate metallization removal)—a
wire bond pull test.
separation between the bonding pad and the underlying sub-
strate.Theinterfacebetweentheballbondandtheresidualpad
6. Inferences
metallization attached to the ball remains intact.
6.1 The most common interference is wire shear in which
3.1.4 cratering—bonding pad lifts taking a portion of the
the ball is sheared too high or offline. Only a minor fragment
underlying substrate material with it. Residual pad and sub-
oftheballisattachedtothewire.Themajorportionoftheball
strate material are attached to the ball. The interface between
remains on the pad with the bond-pad weld interface region
the ball and this residual material remains intact.
intact. Wire shear is illustrated in Fig. 1, View B.
3.1.4.1 Discussion—It should be noted that cratering can be
caused by several factors including the ball bonding operation,
6.2 Many of the common interference modes (such as wire
the post-bonding processing, and even the act of shear testing
shear)arecausedbyimproperpositioningoftheramduringthe
itself. If cratering occurs, chemically etch off the ball bonds
ball shear operation as shown in Fig. 3. Rams that are too high
and bond pads of untested units and microscopically check for
(Fig. 3, View B) or angled upward (Fig. 3, View D) result in
cratering. Cratering caused prior to the shear test operation is
lower than normal shear strength values. Rams that are angled
unacceptable.
downward (Fig. 3, View C and Fig. 4) or positioned too low
Variousaspectsofthefailuremodedefinitionsareillustrated
(Fig. 3, ViewA) will strike the bonding pad and the substrate,
in Fig. 1.
or both, (chip) and cause inordinately high shear strength as
well as potentially damage the shearing ram.
4. Summary of Test Methods
6.3 Shearing gold ball bonds on gold metallization pads or
4.1 The microelectronic device with the ball bond (wire
substratescanleadtofrictionreweldingasillustratedinFig.4.
bond (see Practice F458 and Test Methods F459)) to be tested
Asastronglyweldedgoldbondissheared,theballtendstotip
is held firmly in an appropriate fixture. A shearing ram is
away from the ram and contact the substrate as it moves. The
positionedparalleltothesubstrateandapproximately25µm(1
ball smears against the pad metallization and rewelds itself
mil) above the substrate metallization (except for the case of
often several times before it finally clears the metallization.
fine pitch bond bonds and pads, where the ram height can be
6.4 In bonding systems in which excessive intermetallic
lower, depending on the pitch, final ball height, and so forth.
growthhasformedaroundtheballbond,theshearingrammay
Atypical shearing configuration is shown in Fig. 2.The ram is
contact the intermetallic rather than the ball bond and thus the
then moved into the ball until the ball separates from the
shear readings can be in error (that is, weak ball bond shear is
substrate. The force applied to the ram, in order to cause the
maskedbytheshearstrengthofthestrongintermetallicwreath
failure of the ball bond, is recorded. The mode of failure (for
surrounding it.
example, ball lift, weld-interface separation, cratering, etc.) is
observed and recorded.
6.5 When the bond pad pitch becomes too small to practi-
cally shear test (which appears to be around ≤30 µm pitch with
NOTE 2—Bonds made with larger or smaller diameter wire may require
current equipment) then the only alternative is to use the
thattherambeplacedfurtherabovethesubstrate,orlower,butinallcases
the ram should be located below the ball’s horizontal centerline. The destructive bond pull test, Test Methods F459, and accept that
distance below the center should be at least half the distance between the
resultant value, even if the ball lifts or pulls up the bond pad,
center line and the substrate.
assuming that value is acceptable by pull test criteria.
NOTE 3—Besides ball separation from the substrate, other modes of
failure are possible and will be described in Section 6.
7. Apparatus
5. Significance and Use
7.1 Ball Bond Shearing Machine—Apparatus for measuring
5.1 Failure of microelectronic devices is often due to the the ball bond shear strength are required with the following
components:
failure of an interconnection bond. The most common type of
interconnection bond is the thermosonic gold or copper wire 7.1.1 Shearing Ram—Various shearing tools or rams have
been recommended in the technical literature, but the ones that
bond. A very important element of this interconnection is the
first bond or ball bond. These test methods can assist in appear the most effective have a flat chisel shape with a
shearing edge dimension equal to approximately 1 to 2-ball
maintainingcontroloftheprocessformakingballbonds.They
can be used to distinguish between weak and nonadherent ball diameters as shown in Fig. 5. For 25.4-µm (1-mil) diameter
wire this dimension would be approximately 0.152 mm (6
bonds, of both, and bonds that are acceptably strong.
mils).
5.2 These test methods are appropriate for on-line use in
process control, for process development, for purchase
Harman,G.G.“TheMicroelectronicBall-BondShearTest—ACriticalReview
Charles, Jr., H. K. and Clatterbaugh, G. V., “Ball Bond Shearing—AComple- and Comprehensive Guide to its Use’’, International Journal of Hybrid
menttotheWireBondPullTest,” International Journal of Hybrid Microelectronics, Microelectronics, Vol 6, No. 1, 1983, p. 127; also Harman, G. G., Wire Bonding in
Vol 6, No. 1, 1983, p. 171. Microelectronics, Third Edition, McGraw Hill, 2010, pp. 110-118.
F1269 − 13 (2018)
FIG. 1 Ball Shear Failure Modes
NOTE 4—It has been shown that the shear force is independent of force
7.1.2 Shearing and Gaging Mechanism—Mechanism for
application rate in the range from 0.25 to 6.0 mm/s.
applying a measured vertical (or horizontal) force to the
NOTE 5—Electronic-strain gage-force reading mechanisms are the
shearing is needed. The mechanism shall incorporate a means
industry standard; however, the dynamometer type mechanisms known
for recording maximum force applied and shall be capable of
as“ gram gages’’ may be used satisfactorily providing careful calibration
applyingtheshearforceatauniformrateoframmotion.Force
test procedures are employed.
application rate can be variable (either continuously or in fixed
7.1.2.1 The range of the force reading gage/sensor shall be
steps) to accommodate different shearing conditions and
selected so that the maximum scale reading will be no greater
configurations,orboth.Innocaseshouldtheramspeedexceed
6.0 mm/s. than three times the expected average ball bond shear strength.
F1269 − 13 (2018)
NOTE 1—Schematic diagrams of the ball shear test. (A) Horizontal sample and horizontal ram. (B) Horizontal sample and vertical ram.
FIG. 2 Ball Shear Test Configurations
FIG. 3 Ball Shear Interferences
Anticipated force ranges for the various wire sizes and mate- 7.1.4 Device Holder—A clamping mechanism for rigidly
rials covered by these test methods are summarized in Fig. 6. holding the device under test in either a horizontal or vertical
position depending upon shear tester configuration is required
NOTE 6—The maximum scale range of the electronic strain gage with
(see 7.2).
digital readout may be larger than three times the expected average shear
strength providing the accuracy specified in 10.7.6 is maintained over the
7.1.5 Calibration Masses—At least five masses (weights)
entire range of the load cell.
with mass values known to an accuracy of 0.5% (or better,
7.1.3 Microscope and Light Source—Zoom microscope such as NBS Class T or IOLM Class M2 (NBS Handbook
with a light source for viewing the device under test is needed. 105-1 and Circular 547. IOLM) ) sized to cover the shearing
The minimum magnification shall be at least 60×. and gaging mechanism range of force measurements and
F1269 − 13 (2018)
FIG. 4 Gold-to-Gold Friction Rewelding
suitably configured so that they may be supported by the shear representative of the ball bonds of interest. The size of the
mechanismforcalibration,areneeded.Inthecaseofhorizontal sampleandthemethodofselectionshallbeagreeduponbythe
shearingrammotion,thetestermechanismshouldrotate90°to parties to the test. The sample space should be as large as
allow the weights to be hung from the shearing ram. Other practical (nominally 35 bonds) to ensure the proper statistical
indirect methods of calibration may also be possible for this inferences from quantities such as the mean shear force ¯( X)
configuration. and its standard deviation (σ).
7.1.6 Shear Test Tolerances—The shear test sample holder
orthesheartestrammustbeabletobepositionedtotolerances 9. Calibration
better than 610 µm (6 0.4 mils) and the X and Y directions
9.1 Calibrate the ball bond shearing machine at the begin-
(plane of the bonding pad) and 5.0 µm (60.2 mils) in the Z or
ning and of each series of tests, or at the beginning and end of
the above substrate direction. The shearing rams over travel
each day if the test sequence spans more than one day.
(distance it proceeds from the point of ball contact) should be
9.2 For multifunction wire test machines, set up the test
limited to 2-bal
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F1269 − 13 (Reapproved 2018)
Standard Test Methods for
Destructive Shear Testing of Ball Bonds
This standard is issued under the fixed designation F1269; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 These test methods cover tests to determine the shear 2.1 ASTM Standards:
strength of a series of ball bonds made by either thermosonic F458 Practice for Nondestructive Pull Testing of Wire Bonds
or thermal compression techniques using either gold or copper F459 Test Methods for Measuring Pull Strength of Micro-
wires. electronic Wire Bonds
2.2 NIST Documents:
NOTE 1—Common usage at the present time considers the term “ball
bond’’ to include the enlarged spheriodal or nailhead portion of the wire,
NBS Handbook 105-1 Specification and Tolerances for Ref-
(produced by the flameoff/spark [EFO] and first bonding operation in the
erence Standards and Field Standards, Weights and Mea-
thermosonic [or thermal compression] process), and the ball bond-
sures
bonding pad interfacial-attachment area or weld interface.
IOLM Class M2-Circular 547-1 Precision Laboratory Stan-
1.2 These test methods cover ball bonds made with small
dards of Mass and Laboratory Weights
diameter (from 18 to 76-µm (0.0007 to 0.003-in.)) gold or
2.3 Military Standard:
copper wire of the type used in integrated circuits and hybrid
MIL-STD 883, Method 2010
microelectronic assemblies, system on a chip, and so forth.
1.3 These test methods can be used only when the ball
3. Terminology
height and diameter are large enough and adjacent interfering
3.1 Definitions of Terms Specific to This Standard:
structures are far enough away to allow suitable placement and
3.1.1 ball lift—a separation of the ball bond at the bonding
clearance (above the bonding pad and between adjacent bonds)
pad interface with little or no residual (less than 25 % of the
of the shear test ram.
bond deformation area) ball metallization remaining on the
1.4 These test methods are destructive. They are appropriate
bonding pad (that remains essentially intact). In the case of
for use in process development or, with a proper sampling plan,
gold ball bonds on aluminum pad metallization, a ball lift is
for process control or quality assurance.
defined as a separation of the ball bond at the bonding pad
interface with little or no intermetallic formation either present
1.5 The values stated in SI units are to be regarded as the
or remaining (area of intermetallic less than 25 % of the bond
standard. The values given in parentheses are for information
deformation area).
only.
3.1.1.1 Discussion—Intermetallic refers to the aluminum
1.6 This standard does not purport to address all of the
gold alloy formed at the ball bond pad metallization interfacial
safety concerns, if any, associated with its use. It is the
area where a gold ball bond is attached to an aluminum pad
responsibility of the user of this standard to establish appro-
metallization. If the wire/ball is of copper, then the aluminum
priate safety, health, and environmental practices and deter-
intermetallic is normally much thinner and may not be opti-
mine the applicability of regulatory limitations prior to use.
cally observable.
1.7 This international standard was developed in accor-
3.1.2 ball shear (weld interface separation)— an appre-
dance with internationally recognized principles on standard-
ciable intermetallic (in the case of the aluminum-gold system)
ization established in the Decision on Principles for the
and ball metallization, or both, (in the case of the gold-to-gold
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
These test methods are under the jurisdiction of ASTM Committee F01 on Standards volume information, refer to the standard’s Document Summary page on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic the ASTM website.
Materials, Wire Bonding, and Flip Chip. Available from the National Technical Information Service, 5285 Port Royal
Current edition approved March 1, 2018. Published April 2018. Originally Rd., Springfield, VA 22161.
approved in 1989. Last previous edition approved in 2013 as F1269–13. DOI: Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
10.1520/F1269-13R18. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1269 − 13 (2018)
system) remains on the bonding pad (area of remaining metal specifications, and for research in support of improved yield
or intermetallic greater than 25 % of the bond deformation and reliability. Since the ball shearing method tests only the
area). first bond in a microelectronic wire bond interconnection
5 ,6
system, it must be used in a complementary fashion with the
3.1.3 bonding pad lift (substrate metallization removal)—a
wire bond pull test.
separation between the bonding pad and the underlying sub-
strate. The interface between the ball bond and the residual pad
6. Inferences
metallization attached to the ball remains intact.
6.1 The most common interference is wire shear in which
3.1.4 cratering—bonding pad lifts taking a portion of the
the ball is sheared too high or offline. Only a minor fragment
underlying substrate material with it. Residual pad and sub-
of the ball is attached to the wire. The major portion of the ball
strate material are attached to the ball. The interface between
remains on the pad with the bond-pad weld interface region
the ball and this residual material remains intact.
intact. Wire shear is illustrated in Fig. 1, View B.
3.1.4.1 Discussion—It should be noted that cratering can be
caused by several factors including the ball bonding operation,
6.2 Many of the common interference modes (such as wire
the post-bonding processing, and even the act of shear testing
shear) are caused by improper positioning of the ram during the
itself. If cratering occurs, chemically etch off the ball bonds
ball shear operation as shown in Fig. 3. Rams that are too high
and bond pads of untested units and microscopically check for
(Fig. 3, View B) or angled upward (Fig. 3, View D) result in
cratering. Cratering caused prior to the shear test operation is
lower than normal shear strength values. Rams that are angled
unacceptable.
downward (Fig. 3, View C and Fig. 4) or positioned too low
Various aspects of the failure mode definitions are illustrated
(Fig. 3, View A) will strike the bonding pad and the substrate,
in Fig. 1.
or both, (chip) and cause inordinately high shear strength as
well as potentially damage the shearing ram.
4. Summary of Test Methods
6.3 Shearing gold ball bonds on gold metallization pads or
4.1 The microelectronic device with the ball bond (wire
substrates can lead to friction rewelding as illustrated in Fig. 4.
bond (see Practice F458 and Test Methods F459)) to be tested
As a strongly welded gold bond is sheared, the ball tends to tip
is held firmly in an appropriate fixture. A shearing ram is
away from the ram and contact the substrate as it moves. The
positioned parallel to the substrate and approximately 25 µm (1
ball smears against the pad metallization and rewelds itself
mil) above the substrate metallization (except for the case of
often several times before it finally clears the metallization.
fine pitch bond bonds and pads, where the ram height can be
6.4 In bonding systems in which excessive intermetallic
lower, depending on the pitch, final ball height, and so forth.
growth has formed around the ball bond, the shearing ram may
A typical shearing configuration is shown in Fig. 2. The ram is
contact the intermetallic rather than the ball bond and thus the
then moved into the ball until the ball separates from the
shear readings can be in error (that is, weak ball bond shear is
substrate. The force applied to the ram, in order to cause the
masked by the shear strength of the strong intermetallic wreath
failure of the ball bond, is recorded. The mode of failure (for
surrounding it.
example, ball lift, weld-interface separation, cratering, etc.) is
observed and recorded.
6.5 When the bond pad pitch becomes too small to practi-
cally shear test (which appears to be around ≤30 µm pitch with
NOTE 2—Bonds made with larger or smaller diameter wire may require
current equipment) then the only alternative is to use the
that the ram be placed further above the substrate, or lower, but in all cases
the ram should be located below the ball’s horizontal centerline. The destructive bond pull test, Test Methods F459, and accept that
distance below the center should be at least half the distance between the
resultant value, even if the ball lifts or pulls up the bond pad,
center line and the substrate.
assuming that value is acceptable by pull test criteria.
NOTE 3—Besides ball separation from the substrate, other modes of
failure are possible and will be described in Section 6.
7. Apparatus
5. Significance and Use
7.1 Ball Bond Shearing Machine—Apparatus for measuring
the ball bond shear strength are required with the following
5.1 Failure of microelectronic devices is often due to the
failure of an interconnection bond. The most common type of components:
7.1.1 Shearing Ram—Various shearing tools or rams have
interconnection bond is the thermosonic gold or copper wire
bond. A very important element of this interconnection is the been recommended in the technical literature, but the ones that
appear the most effective have a flat chisel shape with a
first bond or ball bond. These test methods can assist in
maintaining control of the process for making ball bonds. They shearing edge dimension equal to approximately 1 to 2-ball
diameters as shown in Fig. 5. For 25.4-µm (1-mil) diameter
can be used to distinguish between weak and nonadherent ball
bonds, of both, and bonds that are acceptably strong. wire this dimension would be approximately 0.152 mm (6
mils).
5.2 These test methods are appropriate for on-line use in
process control, for process development, for purchase
Harman, G. G. “The Microelectronic Ball-Bond Shear Test—A Critical Review
Charles, Jr., H. K. and Clatterbaugh, G. V., “Ball Bond Shearing—A Comple- and Comprehensive Guide to its Use’’, International Journal of Hybrid
ment to the Wire Bond Pull Test,” International Journal of Hybrid Microelectronics, Microelectronics, Vol 6, No. 1, 1983, p. 127; also Harman, G. G., Wire Bonding in
Vol 6, No. 1, 1983, p. 171. Microelectronics, Third Edition, McGraw Hill, 2010, pp. 110-118.
F1269 − 13 (2018)
FIG. 1 Ball Shear Failure Modes
NOTE 4—It has been shown that the shear force is independent of force
7.1.2 Shearing and Gaging Mechanism—Mechanism for
application rate in the range from 0.25 to 6.0 mm/s.
applying a measured vertical (or horizontal) force to the
NOTE 5—Electronic-strain gage-force reading mechanisms are the
shearing is needed. The mechanism shall incorporate a means
industry standard; however, the dynamometer type mechanisms known
for recording maximum force applied and shall be capable of
as“ gram gages’’ may be used satisfactorily providing careful calibration
applying the shear force at a uniform rate of ram motion. Force
test procedures are employed.
application rate can be variable (either continuously or in fixed
7.1.2.1 The range of the force reading gage/sensor shall be
steps) to accommodate different shearing conditions and
configurations, or both. In no case should the ram speed exceed selected so that the maximum scale reading will be no greater
6.0 mm/s. than three times the expected average ball bond shear strength.
F1269 − 13 (2018)
NOTE 1—Schematic diagrams of the ball shear test. (A) Horizontal sample and horizontal ram. (B) Horizontal sample and vertical ram.
FIG. 2 Ball Shear Test Configurations
FIG. 3 Ball Shear Interferences
Anticipated force ranges for the various wire sizes and mate- 7.1.4 Device Holder—A clamping mechanism for rigidly
rials covered by these test methods are summarized in Fig. 6. holding the device under test in either a horizontal or vertical
position depending upon shear tester configuration is required
NOTE 6—The maximum scale range of the electronic strain gage with
(see 7.2).
digital readout may be larger than three times the expected average shear
strength providing the accuracy specified in 10.7.6 is maintained over the
7.1.5 Calibration Masses—At least five masses (weights)
entire range of the load cell.
with mass values known to an accuracy of 0.5 % (or better,
7.1.3 Microscope and Light Source—Zoom microscope such as NBS Class T or IOLM Class M2 (NBS Handbook
with a light source for viewing the device under test is needed. 105-1 and Circular 547. IOLM) ) sized to cover the shearing
The minimum magnification shall be at least 60×. and gaging mechanism range of force measurements and
F1269 − 13 (2018)
FIG. 4 Gold-to-Gold Friction Rewelding
suitably configured so that they may be supported by the shear representative of the ball bonds of interest. The size of the
mechanism for calibration, are needed. In the case of horizontal sample and the method of selection shall be agreed upon by the
shearing ram motion, the tester mechanism should rotate 90° to parties to the test. The sample space should be as large as
allow the weights to be hung from the shearing ram. Other practical (nominally 35 bonds) to ensure the proper statistical
indirect methods of calibration may also be possible for this inferences from quantities such as the mean shear force (¯ X)
configuration. and its standard deviation (σ).
7.1.6 Shear Test Tolerances—The shear test sample holder
or the shear test ram must be able to be positioned to tolerances
9. Calibration
better than 610 µm (6 0.4 mils) and the X and Y directions
9.1 Calibrate the ball bond shearing machine at the begin-
(plane of the bonding pad) and 5.0 µm (60.2 mils) in the Z or
ning and of each series of tests, or at the beginning and end of
the above substrate direction. The shearing rams over travel
each day if the test sequence spans more than one day
...
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