剪切力实验标准

DIESHEARSTRENGTH1.PURPOSE.Thepurposeofthistestistodeterminetheintegrityofmaterialsandproceduresusedtoattachsemiconductordieorsurfacemountedpassiveelementstopackageheadersorothersubstrates.Thisdeterminationisbasedonameasureofforceappliedtothedie,thetypeoffailureresultingfromthisapplicationofforce(iffailureoccurs)andthevisualappearanceoftheresidualdieattachmediaandsubstrate/headermetallization.2.APPARATUS.Thetestequipmentshallconsistofaload-applyinginstrumentwithanaccuracyof5percentoffullscaleor50grams,whicheveristhegreatertolerance.Acirculardynamometerwithaleverarmoralinearmotionforceapplyinginstrumentmaybeusedtoapplytheforcerequiredfortesting.Thetestequipmentshallhavethefollowingcapabilities:a.Adiecontacttoolwhichappliesauniformdistributionoftheforcetoanedgeofthedie(seefigure2019-1).Acompliant(conforming)material(e.g.,nailpolish,tape,etc.)maybeappliedtothefaceofthecontacttooltoensueuniformforcedistributionontheedgeofthedie.b.Provisionstoassurethatthediecontacttoolisperpendiculartothediemountingplaneoftheheaderorsubstrate.c.Arotationalcapability,relativetotheheader/substrateholdingfixtureandthediecontacttool,tofacilitatelinecontactontheedgeofthedie;i.e.,thetoolapplyingtheforcetothedieshallcontactthedieedgefromend-to-end(seefigure2019-2).d.Abinocularmicroscopewithmagnificationcapabilitiesof10Xminimumandlightingwhichfacilitatesvisualobservationofthedieanddiecontacttoolinterfaceduringtesting.3.PROCEDURE.Thetestshallbeconducted,asdefinedherein,ortothetestconditionsspecifiedintheapplicablespecificacquisitiondocumentconsistentwiththeparticularpartconstruction.Alldiestrengthtestsshallbecountedandthespecificsampling,acceptance,andaddedsampleprovisionsshallbeobserved,asapplicable.3.1Shearstrength.Aforcesufficienttoshearthediefromitsmountingorequaltotwicetheminimumspecifiedshearstrength,whicheveroccursfirst,shallbeappliedtothedieusingtheapparatusof2above.NOTE:Forpassiveelementsonlyattachedattheendterminations,theareausedtodeterminetheforceappliedshallbethetotalareaofthemountingsurfaceoftheendterminations.Anareabetweenandterminationsfilledwithnon-adheringfillershallnotbeusedtodeterminetheforceapplied.However,anyadheringmaterialappliedbetweentheendterminationsshallbeusedintheshearcalculation.Iftheareabetweenendterminationscontainsanadheringmaterial,thentheareaoftheadheringmaterialshallbeaddedtotheareaofthemountingsurfacesoftheendterminationsandthattotalareashallbeusedtodeterminetheforceapplied.a.Whenalinearmotionforce-applyinginstrumentisused,thedirectionoftheappliedforceshallbeparallelwiththeplaneoftheheaderorsubstrateandperpendiculartothediebeingtested.b.Whenacirculardynamometerwithaleverarmisemployedtoapplytheforcerequiredfortesting,itshallbepivotedabouttheleverarmaxisandthemotionshallbeparallelwiththeplaneoftheheaderorsubstrateandperpendiculartotheedgeofthediebeingtested.Thecontacttoolingattachedtotheleverarmshallbeataproperdistancetoassureanaccuratevalueofappliedforce.c.Thediecontacttoolshallapplyaforcegraduallyfromzerotoaspecifiedvalueagainstanedgeofthediewhichmostcloselyapproximatesa90anglewiththebaseoftheheaderorsubstratetowhichitisbonded(seefigure2019-3).Forrectangulardie,theforceshallbeappliedperpendiculartothelongersideofthedie.Whenconstrainedbypackageconfigurations,anyavailablesideofthediemaybetestediftheaboveoptionsarenotavailable.d.Afterinitialcontactwiththedieedgeandduringtheapplicationofforce,therelativepositionofthecontacttoolshallnotmoveverticallysuchthatcontactismadewiththeheader/substrateordieattachmedia.Ifthetoolridesoverthedie,anewdiemaybesubstitutedorthediemayberepositioned,providedthattherequirementsof3.1.caremet.3.2Failurecriteria.Adevicewhichfailsanyofthefollowingcriteriashallconstituteafailure.NOTE:(SeeexamplesfordeterminingDIEAREAfollowingfigure2019-4.)3.2.1Epoxyattach.a.Failsdiestrengthrequirements(1.0X)ofFigure2019-4.b.Separationoccurswithastrengthgreaterthantheminimum(1.0X)specifiedinFigure2019-4,butwithlessthan2.0timesthatstrengthandevidencethatlessthan75percentofthedietosubstratecontactareacontainedattachmediumcoverage.Evidenceofadhesionwillbeintheformofattachmediumtotheintendedareaonthesubstrate,theelementorcombinationofboth.NOTE:Residualelementmaterial(siliconorother)attachedindiscreteareasofthedieattachmediumshallbeconsideredasevidencedofadhesion.3.2.2Eutectic,solder,andotherattach.a.Failsdiestrengthrequirements(1.0X)ofFigure2019-4.b.Separationoccurswithastrengthgreaterthantheminimum(1.0X)specifiedinFigure2019-4,butwithlessthan1.25timesthatstrengthandevidencethatlessthan50percentofthedietosubstratecontactareacontainedattachmediumcoverage.Evidenceofadhesionwillbeintheformofattachmediumtotheintendedareaonthesubstrate,theelementorcombinationofboth.c.Separationoccurswithastrengthgreaterthantheminimum(1.0X)specifiedinFigure2019-4,butwithlessthan2.0timesthatstrengthandevidencethatlessthan10percentofthedietosubstratecontactareacontainedattachmediumcoverage.Evidenceofadhesionwillbeintheformofattachmediumtotheintendedareaonthesubstrate,theelementorcombinationofboth.NOTE:Residualelementmateria