1、Designation: F459 13 (Reapproved 2018)Standard Test Methods forMeasuring Pull Strength of Microelectronic Wire Bonds1This standard is issued under the fixed designation F459; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year
2、 of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods cover tests t
3、o determine the pullstrength of a series of wire bonds. Instructions are provided tomodify the methods for use as a referee method. The methodscan be used for wire bonds made with wire having a diameterof from 0.0007 to 0.003 in. (18 to 76 m).NOTE 1Common usage at the present time considers the term
4、 “wirebond” to include the entire interconnection: both welds and the interven-ing wire span.1.2 These test methods can be used only when the loopheight of the wire bond is large enough to allow a suitable hookfor pulling (see Fig. 1) to be placed under the wire.1.3 The precision of these methods ha
5、s been evaluated foraluminum ultra-sonic wedge bonds; however, these methodscan be used for gold and copper wedge or ball bonds.21.4 These methods are destructive. They are appropriate foruse in process development or, with a proper sampling plan, forprocess control or quality assurance.1.5 A nondes
6、tructive procedure is described in PracticeF458.1.6 The values in SI units are to be regarded as standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, h
7、ealth, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Inter
8、national Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3F458 Practice for Nondestructive Pull Testing of Wire Bonds3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1
9、.1 For the purposes of these test methods the followingfailure points are defined:3.1.2 bond-wire junction failurea rupture in the wirewithin two wire diameters of the bond and in which more than25 % of the bonded area is left on the pad after the pull test hasbeen applied.3.1.3 weld interface failu
10、rea rupture in which less than25 % of the bonded area is left on the pad after the pull test hasbeen applied. See pad lifting in 6.6.3.1.4 wire span failurea rupture in the wire other than (1)at a point within two wire diameters of either bond, or (2) at thepoint at which the hook contacted the wire
11、.4. Summary of Test Methods4.1 The microelectronic device with the wire bond to betested is held firmly in an appropriate fixture. A hook ispositioned under the wire midway between the two bonds. Thehook is then raised until the wire bond breaks. The forceapplied to the hook in order to cause failur
12、e of the wire bondis recorded. The point of failure is observed and recorded. Inthe referee method, the force in the wire on breaking iscalculated.5. Significance and Use5.1 Failure of microelectronic devices is often due to failureof an interconnection bond.Acommon type of interconnectionbond is a
13、wire bond. These methods can assist in maintainingcontrol of the process of making wire bonds. They can be used1These test methods are under the jurisdiction of ASTM Committee F01 onElectronics and are the direct responsibility of Subcommittee F01.03 on MetallicMaterials, Wire Bonding, and Flip Chip
14、.Current edition approved March 1, 2018. Published April 2018. Originallyapproved in 1976 as F459 76 T. Last previous edition approved in 2013 asF459 13. DOI: 10.1520/F0459-13R18.2Harman, G. G., ”Microelectronic Ultrasonic Bonding,” NBS Special Publica-tion 400-2, pp. 94-95 and “Wire Bonding in Micr
15、oelectronics,” Third Edition,McGraw Hill, 2010. Also Microelectronics Reliability 51 (2011), Special Issue onCopper bonding.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
16、efer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization establ
17、ished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1to distinguish between weak, nonadherent wire bonds andacceptably strong wire bonds. The methods are destr
18、uctive.5.2 These test methods are appropriate for on-line use forprocess control, for purchase specifications, and for research insupport of improved yield or reliability. The referee methodshould be used for quantitative comparison of pull strengths ofwire bonds.6. Interferences6.1 Failure to cente
19、r the hook along the loop between thetwo bonds or pulling in a direction not lying in the planecontaining the undisturbed loop may invalidate the test since anunbalanced distribution of forces between the two bonds mayresult.6.2 Slippage of the hook along the wire span during pullingmay invalidate t
20、he test because an unbalanced distribution offorces between the two bonds may result.6.3 Careless insertion of the hook may damage either bondor wire and thus invalidate the test.6.4 The presence of vibration or mechanical shock maycause the application of an extraneous force and thus invalidatethe
21、test.6.5 Measured bond-pull force is strongly dependent on theheight of the loop (H+h, as defined in 11.1.1) and thebond-to-bond spacing ( d, as defined in 11.1.1).6.6 For fine pitch ball bonds (60 m pitch), the bond padmay tear and lift during pull testing. Current practice is toaccept this if the
22、pull force is acceptably high under agreedupon requirements, but note it as appropriate. In some cases ofbad peeling, it is necessary to move the pulling hook directlyover the top of the ball bond. This should be noted.7. Apparatus7.1 Bond-Pulling MachineApparatus for measuring wire-bond pull streng
23、th with the following components:7.1.1 HookPulling hook made from a rigid wire such astungsten. The diameter of that part of the hook that contacts thewire loop should be approximately 2.5 times the diameter ofthe wire used to make the wire bond. A suggested hookconfiguration is shown in Fig. 1. The
24、 hook should appear undervisual inspection to have a smooth polished surface with nosharp edges in any part of the hook that contacts the wire loop.The hook should be rigidly mounted in the pulling apparatus.7.1.2 Lifting-and-Gaging Mechanism Mechanism for ap-plying a measured vertical force to the
25、hook. The mechanismshall incorporate a means for recording the maximum forceapplied and shall be capable of applying force at a rate constantto within 2 gf/s (20 mN/s) in the range from 1 to 30 gf/s (10 to290 mN/s) inclusive. A mechanism with a single fixed scaleshall have a maximum scale reading no
26、 greater than three timesthe nominal bond pull strength anticipated.NOTE 2Mechanisms of the dynamometer type known as “gramgages” have been found satisfactory, but currently, electronic gauges(properly calibrated using the manufacturers procedures) are morecommon.7.1.3 Microscope with Light Source Z
27、oom microscopewith light source with a magnification range of approximately14 to 60 with the eyepiece not to exceed 10, for viewingthe device under test.7.1.4 Device Holder Mechanism for holding the deviceunder test (1) in a horizontal position, for Method A, or (2) ineither a horizontal or a tipped
28、 position so that both bonds arein the same horizontal plane, for Method B. For the refereeMethod C, the device holder should provide a measurement, towithin 2, of the angle from the horizontal (which may be zero)through which the device has been tipped.7.1.5 Calibration MassesAt least five masses (
29、weights)with mass values known to within 0.5 % sized to cover thelifting-and-gaging mechanism range of force measurement,and suitably configured so that they may be supported by thepulling mechanism for calibration.8. Sampling8.1 Since the pull-test method is destructive, it shall beperformed on a s
30、ampling basis. The sample selected should berepresentative of the wire bonds of interest. The size of thesample and the method of selection shall be agreed upon by theparties to the test.9. Calibration9.1 Calibrate the bond-pulling machine at the beginning ofeach series of tests, or daily if a serie
31、s spans more than one day.9.2 Assemble the bond-pulling machine in the same con-figuration to be used to perform the wire-bond pull test.FIG. 1 Suggested Configuration for a Pulling HookF459 13 (2018)29.3 Calibrate the lifting-and-gaging mechanism.9.3.1 For mechanisms incorporating a calibrationadju
32、stment, either calibrate the mechanism in accordance withthe manufacturers instructions or in accordance with theprocedure of 9.3.2.9.3.2 For mechanisms without a calibration adjustment, usethe following procedure:9.3.2.1 Select masses that will provide at least five calibra-tion points over the mec
33、hanism range.9.3.2.2 Attach a selected calibration mass to the lifting-and-gaging mechanism. If a lever-arm mechanism (dynamometeror gram gage) is used, rotate the body of the gage in a mannerthat maintains the arm (carrying the hook) in a horizontalorientation.9.3.2.3 Observe and record the measure
34、d force in grams-force (millinewtons).9.3.2.4 Repeat 9.3.2.2 and 9.3.2.3 for each calibration mass(or electronic scale) selected.9.3.2.5 Plot the measured force values as a function of theforces applied by the masses. Use these results to construct acalibration curve.10. Procedures10.1 Method ADevic
35、e in Horizontal Plane:10.1.1 Place the device having the wire bond to be tested inthe device holder so that the plane of the device is horizontal,as judged visually.10.1.2 Position the microscope and light source and focusthe microscope so that the wire bond to be tested is clearly seenin the micros
36、cope field.10.1.3 Position the device holder so that the wire formingthe loop of the wire bond to be tested is under the rigidlymounted pulling hook.10.1.4 While viewing the wire bond through themicroscope, maneuver the hook so that it is under the wire loopto be pulled, and adjust the hook so that
37、it is midway betweenthe two bonds and contacting the wire loop, as judged by eye.10.1.5 Activate the pulling mechanism while observing thewire bond and hook through the microscope. Continue pullinguntil there is failure.10.1.6 If the wire fails at the point of contact with the hook,record the test f
38、or that bond as invalid.10.1.7 Measure and record the force required for breakingthe wire bond. Determine and record the corrected force fromthe calibration curve if the calibration procedure of 9.3.2 wasused. Record the identification of the wire bond and theidentification of the device (substrate)
39、.10.1.8 Examine the remaining parts of the bonds and thewire span at appropriate magnification to determine the natureand location of the failure.10.1.9 Record the failure location as being one of thefollowing:10.1.9.1 First bond at the weld interface,10.1.9.2 First bond at the bond-wire junction,10
40、.1.9.3 In the wire span,10.1.9.4 Second bond at the weld interface,10.1.9.5 Second bond at the bond-wire junction, or10.1.9.6 Other (describe: for example, pad lift-off (see 6.6).NOTE 3The operator will normally be supplied information as towhich is the first bond and which is the second bond.NOTE 4
41、If the tester is electronic with optical placement control, thenall hook placement/positioning is set up during the initial machinecalibration. However, failure mode determination will be evaluated by theoperator.10.2 Method BDevice in Tipped Plane:10.2.1 Place the device having the wire bond to be
42、tested ina device holder capable of tipping.10.2.2 Perform steps 10.1.2 and 10.1.3.10.2.3 Tip the holder (if required) until both bonds appear tobe in sharp focus as viewed through the microscope.NOTE 5Care should be taken not to tip the wire bond about thebond-line axis. However, a judgment by eye
43、through the microscope isadequate, as an error of a few degrees will not significantly alter themeasured pull strength. This tipped-plane method is not consideredapplicable to an optical-electronic or other automatic pull tester.10.2.4 Perform steps 10.1.4 10.1.9.10.3 Method CReferee Method (To be d
44、one with a manualpull tester and full operator participation):10.3.1 Measure and record the horizontal distance (d) be-tween the two bonds, the vertical distance (H) between the twobonds, and the loop height (h) as shown in Fig. 2. Use the sameunit of measurement for d, h, and H.10.3.2 Use either Me
45、thod A or Method B, whichever isappropriate.FIG. 2 Diagram of a Typical Wire BondF459 13 (2018)310.3.3 If Method B is used, read and record the tip angle(the angle through which the device has been tipped from thehorizontal) to within 2.11. Calculation (for Method C)11.1 If the substrate was tipped
46、from the horizontal, calcu-late the force in grams-force (or millinewtons) in the wire atfailure.11.1.1 If failure occurs at the higher of the two bond sites,calculate the force in the wire as follows:2Fhi5 F11Sd2hD2S11H2hDF12cos1Sh1HdDsinGwhere:Fhi= force in the wire on the high side, gf (or mN),F
47、= corrected applied pull force, gf (or mN),d = horizontal distance between the two bonds along aparallel to plane of device,H = vertical distance between the two bond sites along aperpendicular to plane of device,h = loop height as defined in Fig. 2, and = angle through which device has been tipped.
48、11.1.2 If failure occurs at the lower bond site, calculate theforce in the wire as follows:Flo5S11HhDS11H2hD11Fd2 H1h!G2F12cos 2hdsinGwhere Flo= force in the wire at the low side in grams-force(or millinewtons) and the other symbols are as indicated in11.1.1.11.2 If the device was not tipped from th
49、e horizontal,calculate Fhiand Floas follows:Fhi5 F11Sd2hD2S21HhDFlo5 FS11HhDS21HhD11Fd2H1h!G2where the symbols have the same meaning as in 11.1.1 and11.1.2.12. Report12.1 Method AThe report for Method A shall contain thefollowing:12.1.1 Name of the person performing the test,12.1.2 Date of the test,12.1.3 Identification of the wire-bond pull tester,12.1.4 Identification of the device,12.1.5 Identification of each wire bond,12.1.6 Corrected force in grams-force (or millinewtons)required to break the wire bond, and12.1.7 Location of failure
