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JEDECSTANDARDTestMethodforMeasuringWhiskerGrowthonTinandTinAlloySurfaceFinishesJESD22A121.01(RevisionofJESD22A121,May2005)OCTOBER2005JEDECSOLIDSTATETECHNOLOGYASSOCIATIONNOTICEJEDECstandardsandpublicationscontainmaterialthathasbeenprepared,reviewed,andapprovedthroughtheJEDECBoardofDirectorslevelandsubsequentlyreviewedandapprovedbytheJEDEClegalcounsel.JEDECstandardsandpublicationsaredesignedtoservethepublicinterestthrougheliminatingmisunderstandingsbetweenmanufacturersandpurchasers,facilitatinginterchangeabilityandimprovementofproducts,andassistingthepurchaserinselectingandobtainingwithminimumdelaytheproperproductforusebythoseotherthanJEDECmembers,whetherthestandardistobeusedeitherdomesticallyorinternationally.JEDECstandardsandpublicationsareadoptedwithoutregardtowhetherornottheiradoptionmayinvolvepatentsorarticles,materials,orprocesses.BysuchactionJEDECdoesnotassumeanyliabilitytoanypatentowner,nordoesitassumeanyobligationwhatevertopartiesadoptingtheJEDECstandardsorpublications.TheinformationincludedinJEDECstandardsandpublicationsrepresentsasoundapproachtoproductspecificationandapplication,principallyfromthesolidstatedevicemanufacturerviewpoint.WithintheJEDECorganizationthereareprocedureswherebyaJEDECstandardorpublicationmaybefurtherprocessedandultimatelybecomeanANSI/EIAstandard.Noclaimstobeinconformancewiththisstandardmaybemadeunlessallrequirementsstatedinthestandardaremet.Inquiries,comments,andsuggestionsrelativetothecontentofthisJEDECstandardorpublicationshouldbeaddressedtoJEDECattheaddressbelow,orcall(703)907-7559or©JEDECSolidStateTechnologyAssociation20052500WilsonBoulevardArlington,VA22201-3834Thisdocumentmaybedownloadedfreeofcharge;howeverJEDECretainsthecopyrightonthismaterial.Bydownloadingthisfiletheindividualagreesnottochargefororreselltheresultingmaterial.PRICE:PleaserefertothecurrentCatalogofJEDECEngineeringStandardsandPublicationsonlineat!DON’TVIOLATETHELAW!ThisdocumentiscopyrightedbyJEDECandmaynotbereproducedwithoutpermission.Organizationsmayobtainpermissiontoreproducealimitednumberofcopiesthroughenteringintoalicenseagreement.Forinformation,contact:JEDECSolidStateTechnologyAssociation2500WilsonBoulevardArlington,Virginia22201-3834orcall(703)907-7559JEDECStandardNo.22A121.01-i-TestMethodA121.01(RevisionofA121)TestMethodforMeasuringWhiskerGrowthonTinandTinAlloySurfaceFinishesDisclaimerThisdocumentisnotaqualificationstandard.Itcontainsasuiteofrecommendedtinwhiskergrowthtests.Ifthesecommontestsareadopted,thentheindustrycancollectcommonandcomparabledatathatmayimprovetheunderstandingofthefundamentalsofwhiskergrowthandallowscomparisonsbetweentechnologies.Testsinthisdocumentmaybechangedinthefutureasabetterunderstandingofthemechanismscausingtinwhiskergrowthisdeveloped.Basedonavarietyoftestinganddatareviewfromaroundtheglobe,threetestconditionshavebeenidentifiedthatappeartobesuitableformonitoringtinwhiskergrowth.Thethreetestconditionsincludetwoisothermalconditionswithcontrolledhumidityandathermalcyclingcondition.However,thesetestconditionshavenotbeencorrelatedwithlongerenvironmentalexposuresofcomponentsinservice.Thus,thereisatpresentnowaytoquantitativelypredictwhiskerlengthsoverlongtimeperiodsbasedonthelengthsmeasuredintheshort-termtestsdescribedinthisdocument.Atthetimeofwriting,thefundamentalmechanismsoftinwhiskergrowtharenotfullyunderstoodandaccelerationfactorshavenotbeenestablished.Certainapplications,e.g.,militaryoraerospace,mayrequireadditionaland/ordifferenttinwhiskertestsorevaluations.IntroductionThepredominantterminalfinishesonelectroniccomponentshavebeenSn-Pballoys.AstheindustrymovestowardPb-freecomponentsandassemblyprocesses,thepredominantterminalfinishmaterialswillbepureSnandalloysofSn,includingSn-BiandSn-Ag.PureSnandSn-basedalloyelectrodepositsandsolder-dippedfinishesmaygrowtinwhiskers,whichcouldelectricallyshortacrosscomponentterminalsorbreakoffthecomponentanddegradetheperformanceofelectricalormechanicalparts.JEDECStandardNo.22A121.01TestMethodA121.01-ii-(RevisionofA121)JEDECStandardNo.22A121.01Page1-i-TestMethodA121.01(RevisionofA121)TESTMETHODA121TestMethodforMeasuringWhiskerGrowthonTinandTinAlloySurfaceFinishes(FromJEDECBoardBallotJCB-05-58,formulatedunderthecognizanceoftheJC-14.1SubcommitteeonReliabilityTestMethodsforPackagedDevices.)1ScopeThemethodologypresentedinthisdocument,seeAnnexAforprocessflow,isapplicableforstudyingtinwhiskergrowthfromfinishescontainingapredominanceoftin(Sn).Thistestmethodmaynotbesufficientforapplicationswithspecialrequirements,e.g.,militaryoraerospace.Additionalrequirementsmaybespecifiedintheappropriaterequirementsdocument.Thepurposeofthisstandardisto:•Provideanindustry-standardizedsuiteoftestsformeasurementandcomparisonofwhiskerpropensityfordifferentplatingorfinishchemistriesandprocesses.•Provideaconsistentinspectionprotocolfortinwhiskerexamination.•Provideastandardreportingformat.2NormativereferencesJESD22-A104,StandardforTemperatureCyclingIPC7530,Guidelinesfo