ASTM F458-84(1995)e1
(Practice)Standard Practice for Nondestructive Pull Testing of Wire Bonds
Standard Practice for Nondestructive Pull Testing of Wire Bonds
SCOPE
1.1 This practice covers nondestructive testing of individual wire bonds made by either ultrasonic, thermal compression or thermosonic techniques. The test is destructive to nonacceptable wire bonds but is designed to avoid damage to acceptable wire bonds.
Note 1--Common usage at the present time considers the term "wire bond" to include the entire interconnection: both welds and the intervening wire span.
1.2 The practice covers wire bonds made with small-diameter (from 0.0007 to 0.003-in. (18 to 76-m)) wire of the type used in integrated circuits and hybrid microcircuits.
1.3 This practice can be used only when the loop height of the wire bond is large enough to allow a suitable hook for pulling to be placed under the wire.
1.4 While the procedure is applicable to wire of any composition and metallurgical state, criteria are given only for gold and aluminum wire.
1.5 A destructive pull test is used on wire bonds of the same type and geometry to provide the basis for the determination of the nondestructive pulling force to be used in this practice. This may only be used if the sample standard deviation, s, of the pulling forces required to destroy at least 25 of the same wire bonds tested by the destructive pull-test method is less than or equal to 0.25 of the sample average, x. If s > 0.25 x, this practice may not be used.
Note 2--If s > 0.25 x, some aspect of the bonding process is out of control. Following corrective action, the destructive pull-test measurements should be repeated to determine if the s 0.25 xcriterion is met.
1.6 The nondestructive wire-bond pull test is to be performed before any other treatment or screening following bonding and at the same point in processing as the accompanying destructive test. Preferably, this is done immediately after bonding.
1.7 The procedure does not ensure against wire-bond failure modes induced after the test has been performed.
1.8 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.9 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 and health practices and determine the applicability of regulatory limitations prior to use.
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e1
Designation: F 458 – 84 (Reapproved 1995)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Nondestructive Pull Testing of Wire Bonds
This standard is issued under the fixed designation F 458; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Unit of measurement statement was added editorially in March 1995.
1. Scope as the standard. The values given in parentheses are for
information only.
1.1 This practice covers nondestructive testing of individual
1.9 This standard does not purport to address all of the
wire bonds made by either ultrasonic, thermal compression or
safety concerns, if any, associated with its use. It is the
thermosonic techniques. The test is destructive to nonaccept-
responsibility of the user of this standard to establish appro-
able wire bonds but is designed to avoid damage to acceptable
priate safety and health practices and determine the applica-
wire bonds.
bility of regulatory limitations prior to use.
NOTE 1—Common usage at the present time considers the term “wire
2. Referenced Documents
bond” to include the entire interconnection: both welds and the interven-
ing wire span.
2.1 ASTM Standards:
1.2 The practice covers wire bonds made with small- F 219 Methods of Testing Fine Round and Flat Wire for
Electron Devices and Lamps
diameter (from 0.0007 to 0.003-in. (18 to 76-μm)) wire of the
type used in integrated circuits and hybrid microcircuits. F 459 Test Methods for Measuring Pull Strength of Micro-
1.3 This practice can be used only when the loop height of electronic Wire Bonds
the wire bond is large enough to allow a suitable hook for
3. Summary of Practices
pulling to be placed under the wire.
3.1 The use of nondestructive wire-bond pull tests is predi-
1.4 While the procedure is applicable to wire of any
cated on data obtained from destructive pull tests on typical
composition and metallurgical state, criteria are given only for
samples selected from a lot. The maximum safe nondestructive
gold and aluminum wire.
pull-force levels are determined as a function of the metallur-
1.5 A destructive pull test is used on wire bonds of the same
gical properties of the wire and from the calculated mean (x)
type and geometry to provide the basis for the determination of
and standard deviation (s) of the destructive pull-test data
the nondestructive pulling force to be used in this practice. This
determined in accordance with Test Methods F 459.
may only be used if the sample standard deviation, s,ofthe
3.2 The maximum safe nondestructive bond-pull force is
pulling forces required to destroy at least 25 of the same wire
then applied as a screen for individual wire bonds to identify all
bonds tested by the destructive pull-test method is less than or
bonds with pull strength below the predetermined level of
equal to 0.25 of the sample average, x¯.If s > 0.25 x¯, this
acceptability.
practice may not be used.
4. Significance and Use
NOTE 2—If s > 0.25 x¯, some aspect of the bonding process is out of
control. Following corrective action, the destructive pull-test measure-
4.1 The nondestructive wire-bond pull test provides a screen
ments should be repeated to determine if the s # 0.25 x¯ criterion is met.
for evaluating wire-bond quality and is capable of detecting
weak or nonadherent bonds.
1.6 The nondestructive wire-bond pull test is to be per-
4.2 The test is not destructive to acceptable wire bonds.
formed before any other treatment or screening following
4.3 This practice provides a procedure for identifying a
bonding and at the same point in processing as the accompa-
bonding situation that requires corrective action.
nying destructive test. Preferably, this is done immediately
4.4 The purpose of this practice is to identify wire bonds
after bonding.
that may fail during subsequent screening procedures or field
1.7 The procedure does not ensure against wire-bond failure
operation.
modes induced after the test has been performed.
4.5 The procedure is to be applied after bonding and before
1.8 The values stated in inch-pound units are to be regarded
any further treatment.
5. Interferences
This practice is under the jurisdiction of ASTM Committee F-1 on Electronics
5.1 As the force levels of the nondestructive wire-bond pull
and is the direct responsibility of Subcommittee F01.07 on Wire Bonding.
Current edition approved May 25, 1984. Published July 1984. Originally
published as F 458 – 76 T. Last previous edition F 458 – 78. Annual Book of ASTM Standards, Vol 10.04.
F 458
n
test depend upon the correct, consistent application of the
2 2 1 2
/
s 5 @ ~x 2 nx¯! #
H ( i J
n 2 1
destructive wire-bond pull test, the same interferences apply as
i 5 1
given in Test Methods F 459.
8.4 Using Table 1, select the wire composition and
elongation (obtainable from the wire manufacturer), and the
6. Apparatus
relation between x¯ and s appropriate to the wire bond to be
6.1 The apparatus used for the procedure is identical to that
tested and de
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