JESD22-B116A Wire Bond Shear Test

JEDECSTANDARDWireBondShearTestMethodJESD22-B116A(RevisionofJESD22-B116,July1998)AUGUST2009JEDECSOLIDSTATETECHNOLOGYASSOCIATIONNOTICEJEDECstandardsandpublicationscontainmaterialthathasbeenprepared,reviewed,andapprovedthroughtheJEDECBoardofDirectorslevelandsubsequentlyreviewedandapprovedbytheJEDEClegalcounsel.JEDECstandardsandpublicationsaredesignedtoservethepublicinterestthrougheliminatingmisunderstandingsbetweenmanufacturersandpurchasers,facilitatinginterchangeabilityandimprovementofproducts,andassistingthepurchaserinselectingandobtainingwithminimumdelaytheproperproductforusebythoseotherthanJEDECmembers,whetherthestandardistobeusedeitherdomesticallyorinternationally.JEDECstandardsandpublicationsareadoptedwithoutregardtowhetherornottheiradoptionmayinvolvepatentsorarticles,materials,orprocesses.BysuchactionJEDECdoesnotassumeanyliabilitytoanypatentowner,nordoesitassumeanyobligationwhatevertopartiesadoptingtheJEDECstandardsorpublications.TheinformationincludedinJEDECstandardsandpublicationsrepresentsasoundapproachtoproductspecificationandapplication,principallyfromthesolidstatedevicemanufacturerviewpoint.WithintheJEDECorganizationthereareprocedureswherebyaJEDECstandardorpublicationmaybefurtherprocessedandultimatelybecomeanANSIstandard.Noclaimstobeinconformancewiththisstandardmaybemadeunlessallrequirementsstatedinthestandardaremet.Inquiries,comments,andsuggestionsrelativetothecontentofthisJEDECstandardorpublicationshouldbeaddressedtoJEDECattheaddressbelow,orcall(703)907-7559orwww.jedec.orgPublishedby©JEDECSolidStateTechnologyAssociation20093103North10thStreetSuite240SouthArlington,VA22201-2107Thisdocumentmaybedownloadedfreeofcharge;howeverJEDECretainsthecopyrightonthismaterial.Bydownloadingthisfiletheindividualagreesnottochargefororreselltheresultingmaterial.PRICE:PleaserefertothecurrentCatalogofJEDECEngineeringStandardsandPublicationsonlineathttp://www.jedec.org/Catalog/catalog.cfmPrintedintheU.S.A.AllrightsreservedPLEASE!DON’TVIOLATETHELAW!ThisdocumentiscopyrightedbyJEDECandmaynotbereproducedwithoutpermission.Organizationsmayobtainpermissiontoreproducealimitednumberofcopiesthroughenteringintoalicenseagreement.Forinformation,contact:JEDECSolidStateTechnologyAssociation3103North10thStreetSuite240SouthArlington,VA22201-2107orcall(703)907-7559JEDECStandardsNo.22-B116APage1TestMethodB116ARevisionofTestMethodB116TESTMETHODB116AWIREBONDSHEARTEST(FromJEDECBoardBallotJCB-09-62,formulatedunderthecognizanceoftheJC-14.1SubcommitteeonReliabilityTestMethodsforPackagedDevices.)1ScopeThistestprovidesameansfordeterminingthestrengthofagoldballbondtoadiebondingsurfaceoranaluminumwedgeorstitchbondtoadieorpackagebondingsurface,andmaybeperformedonpre-encapsulationorpost-encapsulationparts.Thismeasureofbondstrengthisextremelyimportantindeterminingtwofeatures:1)theintegrityofthemetallurgicalbondwhichhasbeenformed.2)thequalityofgoldandaluminumwirebondstodieorpackagebondingsurfaces.Thesetestmethodscoverballbondsmadewithsmalldiameter(from18to76µm,orfrom0.7to3mil)wireandwedgebondsmadewithlargerdiameter(minimumof3mil)wire,ofthetypeusedinintegratedcircuitsandhybridmicroelectronicassemblies.Thesetestmethodscanbeusedonlywhentheballheight(atleast10.16µmor0.4mil)anddiameterforballbonds,orthewireheight(atleast1.25milsinheightatthecompressedbondedarea)ofthewedgebond,arelargeenoughandadjacentinterferingstructuresarefarenoughawaytoallowsuitableplacementandclearance(abovethebondingpadorleadframepostandbetweenadjacentbonds)ofthesheartestchisel.Thistestmethodmayalsoapplytogoldwedgeorstitchbondsifthewireisthickenoughtoallowshearingofthewirefromthebondingsurfacewithoutsmearingsimilartoashearingskip.Thewirebondsheartestisdestructive.Itisappropriateforuseinprocessdevelopment,processcontroland/orqualityassurance.2TermsanddefinitionsForthepurposesofthisstandard,thefollowingtermsanddefinitionsapply:2.1ballbond:Theadhesionorweldingofathinwire,usuallygold,toadiepadmetallization,usuallyanaluminumalloy,usingathermosonicwirebondprocess.NOTETheballbondincludestheenlargedspherical,ornail-head,portionofthewire(providedbytheflame-offandfirstbondingoperationinthethermalcompressionandthermosonicprocess,orboth),theunderlyingbondingpadandtheballbond-bondingpadintermetallicweldinterface.2.2bondfootprint(ofawedgebond):Theareaofthewirethathasaphysicalbondinterface(intermetallicorrecrystallized)withrespecttothecompressedareaofthewire.JEDECStandardsNo.22-B116APage2TestMethodB116ARevisionofTestMethodB1162Termsanddefinitions(cont’d)2.3bondingsurface:Either1)thediepadmetallizationor2)thepackagesurfacemetallizationtowhichthewireisball-,wedge-,orstitch-bonded.2.4bondshear:Aprocessinwhichaninstrumentusesachisel-shapedtooltoshearorpushaballorwedgebondoffthebondpad(seeFigure1).NOTETheforcerequiredtocausethisseparationisrecordedandisreferredtoasthebondshearforce.Thebondshearforceofagoldballbond,whencorrelatedtothediameteroftheballbond,isanindicatorofthequalityofthemetallurgicalbondbetweenthegoldballbondandthebondpadmetallization.Thebondshearforceofanaluminumwedgebond,whencomparedtothemanufacturer'stensilestrengthofthewire,isanindicatoroftheintegrityoftheweldbetweenthealuminumwireandthebondpadorpackagesurfacemetallization.Figure1—Bondshearset-up2.5bondshearcodesforballandwedgebonds(seeFigure2)2.5.1Type1-bondlift:Aseparationoftheentirewirebondfromthebondingsurfacewithonlyanimprintbeingleftonthebondingsurfaceandverylittleevidenceofintermetallicformationorweldingorofdisturbanceofthebondingsurfacemetallization.NOTEAbondliftmayrequireanassessmentofthebondersettings.2.5.2Type2-bondshear:Aseparationofthewirebondwhere1)athinlayerofthebondingsurfacemetallizationremainswiththewirebondandanimpressionisleftinthebondingsurface,2)intermetallicsremainonthebondingsurfaceandwiththewirebond,or3)amajorportionofthewirebondremainsonthebondingsurface.JEDECStandardsNo.22-B116APage3TestMethodB116ARevisionofTestMethodB1162Termsanddefinitions(cont’d)2.5bondshearcodesforballandwedgebonds(seeFigure2)(cont’d)2.5.3Type3–cratering:Aconditionunderthediepadmetallizationinwhichtheinsulatinglayer(oxideorinterlayerdielectric)andthebulkmaterial(silicon)separateorchipout.NOTE1Separationinterfacesthatshowpitsordepressionsintheinsulatinglayer(notextendingintothebulk)arenotconsideredcraters.NOTE2Crateringcanbecausedbyseveralfactorsincludingthewirebondingoperation,thepost-bondingprocessing,andeventheactofsheartestingitself.NOTE3Crateringpresentpriortothesheartestoperationdenotesapre-existingconditionthatmustbeaddressed.Anybondswithpreexistingcrateringareinvalidforthistestmethodandshallnotbeincludedwiththesheardata.2.5.4Type4-armcontactsspecimen(bondingsurfacecontact):Thesheartoolcontactsthebondingsurfacetoproduceaninvalidshearvalue.NOTEThisconditionmaybeduetoimproperplacementofthespecimen,alowshearheight,orinstrumentmalfunction.Thisbondsheartypeisaninvalidresultandshallbeeliminatedfromthesheardata.2.5.5Type5-shearingskip:Thesheartoolremovesonlythetopmostportionoftheballorwedgebond.NOTEThisconditionmaybeduetoimproperplacementofthespecimen,ahighshearheightorinstrumentmalfunction.Thisbondsheartypeisaninvalidresultandshallbeeliminatedfromthesheardata.2.5.6Type6-bondpad(orbondingsurface)lift:Aseparationbetweenthebondingsurfacemetallizationandtheunderlyingsubstrateorbasematerialwithevidenceofbondingsurfacemetallizationremainingattachedtotheballorwedgebond.JEDECStandardsNo.22-B116APage4TestMethodB116ARevisionofTestMethodB1162TermsandDefinitions(cont’d)2.5DefinitionofBondShearCodesforBallandWedgeBonds(seeFigure2)(cont’d)BondingsurfaceWirebondseparatedfrombondingMajorportionofwirebondBallorWedgebondingweldareaintact.Residualbondingsurfaceandattachedtowirebond.Bondingsurfaceliftedtakingportionofsubstrate(bulk)material.ArmcontactedbondingsurfacemetallizationBondingsurfaceseparatedfromdiesurface.Bondingsurfacemetallizationseparatedfromdiesurface.Minorportionofwirebondattachedtowire.Wirebondshearedtoohigh.OnlyportionofTYPE1:BondLiftTYPE2:BondShear-Gold/AluminumTYPE4:BondingSurfaceContactTYPE3:CrateringTYPE5:ShearingSkipTYPE6:BondingSurfaceLiftsurface.LittleorNOintermetallicwirebondremoved.onbondingsurface.intact.attachedtowire.substrate(bulk)materialinsteadofwirebond.Underlyingbondingpad,andtheballbond-bondingpadintermetallicweldinterfaceFigure2—BondShearCodesExamplesshownhereareforballbonds.Thesesamemodesalsoapplytowedge[stitch]bonds.JEDECStandardsNo.22-B116APage5TestMethodB116ARevisionofTestMethodB1162TermsandDefinitions(cont’d)2.6sheartool;sheararm:Atungstencarbide,orequivalent,chiselwithspecificanglesonthebottomandbackofthetooltoensureashearingaction.2.7wedgebond;stitchbond:Theadhesionorweldofathinwire,usuallyaluminum,toapackagebondingsurface,usuallyaplatedleadframepostorfinger,usinganultrasonicwirebondingprocess.NOTEThewedgebondincludesthecompressed(ultrasonicallybonded)areaofthewireandtheunderlyingbondingsurface.Forbondingtoanaluminumalloydiebondpad,thereisnowedgebond-bondpadintermetallicbecausethetwomaterialsareofthesamecomposition,butthetwomaterialsarerecrystallizedtogetherbytheultrasonicenergyoftheweldingprocess.3ApparatusandmaterialTheapparatusandmaterialsrequiredforbondshearshallbeasfollows:3.1InspectionEquipmentAnopticalmicroscopesystemorscanningelectronmicroscopeprovidingaminimumof70Xmagnification.3.2MeasurementEquipmentAnopticalmicroscope/measurementsystemcapableofmeasuringthebonddiametertowithin±0.0001inch(0.1mil).3.3WorkholderFixtureusedtoholdthepartbeingtestedparalleltotheshearingplaneandperpendiculartothesheartool.Thefixtureshallalsoeliminatepartmovementduringbondsheartesting.Ifusingacalipercontrolledworkholder,placetheholdersothattheshearmotionisagainstthepositivestopofthecaliper.Thisistoensurethattherecoilmovementofthecalipercontrolledworkholderdoesnotinfluencethebondsheartest.3.4BondShearEquipmentThebondshearequipmentmustbecapableofprecisionplacementoftheshearingtool(±2.54µmor±0.10mil)abovethesubstrate.Thespecifieddistance(h)abovethetopmostpartofthebondingsurfaceshallensurethesheartooldoesnotcontactthesurfaceofthedieandshallbelessthanthedistancefromthetopmostpartofthebondingsurfacetothecenterline(CL)oftheballorwedgebond.3.5BondShearToolRequiredsheartoolparametersincludebutarenotlimitedto:flatshearface,sharpshearingedge,shearingwidthofaminimumof1.2Xthebonddiameter,orbondlength.Theshearingtoolshouldbedesignedsoastopreventploughinganddragduringtesting.Thetoolshouldbecleanandfreeofchipsorotherdefectsthatwillinterferewiththeshearingtest.JEDECStandardsNo.22-B116APage6TestMethodB116ARevisionofTestMethodB1164Procedure4.1CalibrationBeforeperformingthebondsheartest,itmustbedeterminedthattheequipmenthasbeencalibratedinaccordancewithmanufacturer'sspecificationsandispresentlyincalibration.Recalibrationisrequirediftheequipmentismovedtoanotherlocation.4.2VisualExaminationofBondstobeTestedAfterDecapsulationIfperformingbondsheartestingonapartwhichhasbeenopenedusingwetchemicaland/ordryetchtechniques,thebondpadsshallbeexaminedtoensurethereisnoabsenceofmetallizationonthebondingsurfaceareaduetochemicaletching,andwirebondsareattachedtothebondingsurface.Thoseballorwedgebondsonbondpadswithsignificantchemicalattackorabsenceofmetallizationshallnotbeusedforballsheartesting.Itispossiblethatwirebondsonbondingsurfaceswithoutdegradationfromchemicalattackmaynotbeattachedtothebondingsurfaceduetoothercauses(e.g.,packagestress).Thesewirebondsareconsideredvalidandshallbeincludedinthesheardataasazero(0)gramvalue.Bondsmustalsobeexaminedtodetermineifadjacentinterferingstructuresarefarenoughawaytoallowsuitableplacementandclearance(abovethebondingsurfaceandbetweenadjacentbonds)forthesheartesttool.4.3SampleSizesSamplesizesshallbeaminimumspecifiedbySPCcontrolsineffectforspecificprocesses,orasspecifiedintheapplicableprocurementdocument4.4MeasurementoftheBallBondDiametertoDeterminetheBallBondShearFailureCriteriaOncethebondingsurfaceshavebeenexaminedandbeforeperformingbondsheartesting,thediameterofallballbondstobetestedshallbemeasuredandrecorded.Forasymmetricalbonds,determinetheaverageusingboththelargest(dlarge)andthesmallest(dsmall)diametervalues(seeFigure3).Theseballbonddiametermeasurementsshallbeusedtodeterminethemean,oraverage,diametervalue.Theresultingmean,oraverage,ballbonddiametershallthenbeusedtoestablishthefailurecriteriaasdefinedinFigure4andTable1.Ifprocessmonitordatahasestablishedthenominalballbonddiameter,thenthatvaluemaybeusedtodeterminethefailurecriteriaasdefinedinFigure4andTable1.JEDECStandardsNo.22-B116APage7TestMethodB116ARevisionofTestMethodB1164Procedure(cont’d)4.4MeasurementoftheBallBondDiametertoDeterminetheBallBondShearFailureCriteria(cont’d)SYMMETRICALASYMMETRICALFigure3—Ballbondmeasurement(symmetricalvs.asymmetrical)MINIMUMSHEARVALUESBALLBONDDIAMETER(mils)2.252.53.03.253.53.754.254.54.755.05.252.0SHEARSTRENGTH(grams)1.7501020304050607080901001102.754.0MinimumIndividualShearReadingMinimumSampleAverageFigure4—Minimumrecommendedindividualandaverageballbondshearvalues(seeTable1forexactbondshearvalues)JEDECStandardsNo.22-B116APage8TestMethodB116ARevisionofTestMethodB1164Procedure(cont’d)Table1—MinimumrecommendedindividualandsampleaverageballbondshearvaluesDiameter(mils)MinimumShearAverage(grams)MinimumIndividualShearReading(grams)2.012.65.72.114.06.82.215.58.12.317.19.52.418.810.92.520.612.42.622.414.02.724.415.62.826.517.42.928.619.23.030.821.13.133.223.13.235.625.13.338.127.23.440.729.43.543.431.73.646.234.13.749.136.53.852.139.13.955.241.74.058.344.34.161.647.14.265.050.04.368.452.94.471.955.84.575.659.04.679.362.14.783.165.34.887.068.64.991.072.05.095.175.5NOTETheseshearvaluesareapplicabletogoldwireballbondsonaluminumalloybondingsurfacesJEDECStandardsNo.22-B116APage9TestMethodB116ARevisionofTestMethodB1164Procedure(cont’d)4.PerformingtheBondShearTestThebondshearequipmentshallpassallselfdiagnostictestsbeforebeginningthetest.Thebondshearequipmentandtestareashallbefreeofexcessivevibrationormovement.Examinethesheartooltoverifyitisingoodconditionandisnotbentordamaged.Checkthesheartooltoverifyitisintheupposition.Adjusttheworkholdertomatchthepartbeingtested.Securetheparttotheworkholder.Makesurethesurfaceofthedieisparalleltotheshearingplaneofthesheartool.Itisimportantthatthesheartooldoesnotcontactthesurfaceofthedieoradjacentstructuresduringtheshearingoperationasthiswillgiveincorrecthighreadings.Positionthepartsothatthebondtobetestedislocatedadjacenttothesheartool.Lowerthesheartool,orraisethepartdependinguponshearequipmentused,toapproximatelythesurfacefromwhichthebondistobeshearedbutnotcontactingthesurface(approximatelythethicknessofthebondabovethesurface).Positiontheballbondtobetestedsothattheshearmotionwilltravelperpendiculartothesurfaceedge.Positionthewedgebondtobetestedsothattheshearmotionwilltraveltowardthelongsideofthewedgebondandisfreeofanyinterference(i.e.sheartheoutsidebondfirstandthensheartowardtheshearedwedgebond).Positionthesheartoolwithinapproximatelyoneball(forballbonds)orwirediameter(forwedge/stitchbonds)ofthebondtobesheartestedandshearthebond.4.6ExaminationofShearedBondsAllbondsshallbeshearedinaplanned/definedsequencesothatlatervisualexaminationcandeterminewhichshearvaluesshouldbeeliminatedbecauseofanimpropershear.Thebondsshallbeexaminedusingatleast70Xmagnificationtodetermineifthesheartoolskippedoverthebond(type5)orthetoolscrapedorplowedintothesurfaceofthedie(type4).Type4and5defectiveshearconditionsareinvalid,andshallbeeliminatedfromthesheardata(seeFigure2).Shearedbondsinwhichatype3crateringconditionhasoccurredshallbeinvestigatedfurthertodeterminewhetherthecrackingand/orcrateringisduetothebondingprocessortheactofsheartesting.Crateringcausedpriortothesheartestoperationisinvalidandshallbeeliminatedfromthesheardata.Crateringresultingfromtheactofsheartestingshallbeconsideredvalidandincludedinthesheardata.4.7FootprintInspectionofAluminumWedgeBondsAllwirebondingprocessestoboththediebondpadandtheleadframepostshallhaveabondfootprintinspectionperformed.Forwirestoosmallforbondsheartesting(lessthan1.25milsinheightatthecompressedbondedarea),thewireshallberemovedatthebondlocationusingasmallsharpblade.Theremovalofthewireshallbesufficientsuchthatthebondinterfacecanbevisuallyinspectedandthemetallurgicalbondareadetermined.Forlargerwiresafterbondsheartesting,alldevicesshallbeinspectedtoexaminethefailuremodeandtodeterminethebondfootprintcoverage.JEDECStandardsNo.22-B116APage10TestMethodB116ARevisionofTestMethodB1164Procedure(cont’d)4.8BondShearDataDatashallbemaintainedforeachbondsheared.Thedatashallidentifythebond(location,bonddiameter,wirematerial,methodofbonding,andmaterialbondedto),theshearstrength,andtheshearcodenumber.4.9ShearCodesForeachbondsheared,acodeasdefinedinFigure2shallberecorded.5FailurecriteriaThefollowingfailurecriteriaarenotvalidfordevicesthathaveundergoneenvironmentalstresstesting,havebeendesolderedfromcircuitboards,orwerepreconditionedpriortodecapsulation(ifprocurementorqualificationdocumentsrequiredthatthesamplesbepreconditionedpriortotheperformingofthistestmethod).5.1FailureCriteriaforBallBondsTherecommendedminimumindividualandsampleaveragebondshearvaluesareshowninFigure4andTable1.Thesecriteriaareapplicabletogoldwireballbondsonaluminumalloybondpads.Othermaterialcombinationsmayrequireanewsetoffailurecriteria.Alternateminimumbondshearvaluesmaybeproposedbythesupplierifsupportingdatajustifiestheproposedminimumvalues.5.2FailureCriteriaforAluminumWedgeBondsThewedgebondsonapartshallbeconsideredacceptableiftheminimumshearvaluesareequaltoorgreaterthanthemanufacturer'stensilestrengthofthebondwire.Inaddition,thepercentofthebondfootprintinwhichbondingshouldoccurshallbenolessthan50%.IfitisnecessarytocontrolthewirebondingprocessusingSPCforpercentcoverage,aCpkvaluecanbecalculatedtothislimit.6SummaryThequalitylevelandtestconditionsarecontainedwithinthisdocumentunlessotherwisespecifiedintheapplicablePartSpecificationand/orPartDrawing.JEDECStandardsNo.22-B116APage11TestMethodB116ARevisionofTestMethodB116AnnexA(informative)DifferencesbetweenJESD22-B116AandJESD22-B116Thistablebrieflydescribesmostofthechangesmadetoentriesthatappearinthisstandard,JESD22-B116A,comparedtoitspredecessor,JESD22-B116(July1998).Ifthechangetoaconceptinvolvesanywordsaddedordeleted(excludingdeletionofaccidentallyrepeatedwords),itisincluded.Somepunctuationchangesarenotincluded.Page-ClauseDescriptionofchange1-2Addeddefinitionfortheterm‘bondfootprint’renumberedremainingclauses,editorialchangestoalldefinitionstomeetJEDECStyleManual.2-2Addednotetostatethatatype1shearmayrequireevaluationofbondersettings3-2Changedreferencetopre-existingbondcraterintoanote3-2Changedterminologyfrom‘unacceptable’to‘invalid’forsheartypesthatshouldnotbeincludedinsheartestresults4-2Addedtexttofigure6thatwasomittedinoriginalreleaseofstandard.Textwasincorrectlyaddedtoendofclause2.65-2Addeddefinitionfor‘BondFootprint’7-4CorrectederrorsinFigure39-4Changedterminologyfrom‘unacceptable’to‘invalid’forsheartypesthatshouldnotbeincludedinsheartestresults10-5AddedstatementregardingpreconditioningofsamplespriortoperformingthistestmethodJEDECStandardsNo.22-B116APage12TestMethodB116ARevisionofTestMethodB116StandardImprovementFormJEDECJEDS22B116AThepurposeofthisformistoprovidetheTechnicalCommitteesofJEDECwithinputfromtheindustryregardingusageofthesubjectstandard.IndividualsorcompaniesareinvitedtosubmitcommentstoJEDEC.Allcommentswillbecollectedanddispersedtotheappropriatecommittee(s).Ifyoucanprovideinput,pleasecompletethisformandreturnto:JEDECAttn:PublicationsDepartment3103North10thStreet,Suite240SArlington,VA22201Fax:703.907.75831.Irecommendchangestothefollowing:Requirement,clausenumberTestmethodnumberClausenumberThereferencedclausenumberhasproventobe:UnclearTooRigidInErrorOther2.Recommendationsforcorrection:3.Othersuggestionsfordocumentimprovement:SubmittedbyName:Phone:Company:E-mail:Address:City/State/Zip:Date: