面对铜线挑战的劈刀解决方案

CapillarySolutionsforCopperWireBondingChallengesChallenge-CapillaryknowledgeandchallengesforCopperwirebonding2ndbondrelatedchallengesPadDamageCapWearCapCloggingProcessFan-outKnowledge-processinfluenceoncapillarywear,cloggingGoldvs.CopperWirebondingProcessWearshaperelatedtoBallbondvs.WedgeBondByWiretype–Auvs.BareCuvs.PdcoatedByProcesstype–TCvsTSByleadframetype–PPFvsSilverplatedCloggingrootcausefishboneSolution-CurrentcapillarydesignstomeetcopperchallengesK&SITAmaterialK&SGranularmorphologyE-CuPRA3Gcapillarydesign:BasedonlifeperformanceofCuPRA3GdesignLowerUSGBetterprocessportabilityR&DCapabilitiesAgendaChallengeKnowledgeSolution-CONFIDENTIAL-23CapillaryKnowledgeandChallengesforCopperWireBondingDifferencebetweenXandYAxisAlSplash,MetalliftWearoutatCapillarytipCloggingProcessFan-out-CONFIDENTIAL-3CHALLENGEImprovementsinbondercapabilities,capillarydesign,wirematerialandthebondingprocesshavemadethecopperwire2ndbondsignificantlyeasiertooptimizeandincreasesit’sreliabilityandrobustnessBarecopperwireisdifficulttobondcomparedtoPd–coatedcopperwireRoughµPPFleadframesandQFNleadframesarebothchallengingforthecopper2ndbond.TheHardandrelatively“slippery”outeroxidelayerofthecopperwiremakeithardertodeformthestitch.Pd-coatedwirewhilebeingharderthancoppercreateshigherfrictionforceseasingdeformation.Stitchpeelingandprematuretailbreakage(SHTL)bothassociatedwiththecopperwire’stendencytoworkhardenduringstitchdeformationarestillthemostcommonprocesschallenges42ndbondrelatedchallengesUltrasonicDirectionCapillaryelongatesthestitchandtailbondCapillarywidensthestitchandtailbondX-AxisY-AxisX/YprocessdifferencesPd-Coatedvs.BarecopperStitchpullStitchpeelingPd-Coatedvs.BarecopperDragforcecomparisonTailBond-CONFIDENTIAL-CHALLENGE5GoldCopperPadDamageandAluminumsplashFABhardness[Hv]Wire60Gold90CopperCuprocesshaveroughlya25%increaseinthemaximumstresscomparedtoanequivalentAuballbondPadDamageAluminumsplash-CONFIDENTIAL-Wiretype,leadframetypeandprocesstypeallaffectcapillarywear-outincopperWear-outchangesthemorphologyandgeometryoftheoriginalcapillaryresultingin:Machineassists2ndbonddegradation(stitchpull,shape)CHALLENGECapillaryWearout-CONFIDENTIAL-63456789100200400600800100012001400StitchPull[gr]Lifespan[kb]Avg.stitchpullMin.stitchpullFailtomeetspec.BPP:50umWire:Hereaus0.8milMaxsoftCuwireSubstrate:QFP68LSamplesize:40measurementsCHALLENGECloggingMostcustomersconvertingtocopperwireexperiencehigherfrequencyofcapillaryclogging:CuandPd-coatedCuwiremechanicalpropertiesHigherfrequencyofNSOPduetopaddamageandballoxidationHigherFrequencyofSHTLoccurrences-CONFIDENTIAL-NSOPrelatedcloggingSHTLrelatedclogging78ThehardcopperFABincreasesthechallengeofpadpeeling/crackingduring1stbondformation.ThehardcopperFABalsocausesincreasedAluminumsplash,resultinginpadtopadelectricalshortsandleavingnoaluminumunderneaththebondedball.Theresultingsmallerprocesswindowmakelargescaleprocessfan-outacrossmultiple:machines/capillaries/materiallots,aparticularchallengeincopperbondingCopperwireGoldwireCHALLENGEMultipleCapillariesMultiplemachinesTight1stbondprocesswindow–Processfan-out-CONFIDENTIAL-Knowledge–processinfluenceoncapillarywear&cloggingGoldvs.CopperWirebondingProcessWearShaperelatedtoBallbondv.sWedgeBondByWiretype-Auvs.BareCuvs.PdcoatedByProcesstype-USGvalueeffectByProcesstype-TCvs.TSByleadframetype–PPFvs.SilverplatedCloggingrootcausefishbone-CONFIDENTIAL-9KNOWLEDGE10300kb300kbGoldCopperEventhoughbothwireswerebondedusingthesamemachineparameters,whereonlyoccurredwiththeabrasivecopperwire.ConFocalmicroscopeimagery@1000X•Bonder:K&SMaxumultra•Wire:Maxsoft1.0mil•Package:BareQFPDevicePaddle•Capillary:CuPRAplusBondingdirectionBondingdirectionBuildupNobuildupvisibleGoldvs.CopperWireBondingProcessAggressiveacceleratedbondingprocessusedbondingonlyinYaxis.samemachineparameterswereusedforbothwiretypesPropertiesUnitsCopperGoldAluminiumDensityg/cm38.9219.322.7ThermalConductivityCal/cmsecoC0.940.740.21ElectricalResistivity(20oC)-cm1.92.32.7CTE(0-100oC)ppm/oC171424Young'sModulusGPa1208070TensileStrengthMPa290140150PropertiesUnitsCopperGoldAluminiumDensityg/cm38.9219.322.7ThermalConductivityCal/cmsecoC0.940.740.21ElectricalResistivity(20oC)-cm1.92.32.7CTE(0-100oC)ppm/oC171424Young'sModulusGPa1208070TensileStrengthMPa290140150PropertiesUnitsCopperGoldAluminiumDensityg/cm38.9219.322.7ThermalConductivityCal/cmsecoC0.940.740.21ElectricalResistivity(20oC)-cm1.92.32.7CTE(0-100oC)ppm/oC171424Young'sModulusGPa1208070TensileStrengthMPa290140150PropertiesUnitsCopperGoldAluminiumDensityg/cm38.9219.322.7ThermalConductivityCal/cmsecoC0.940.740.21ElectricalResistivity(20oC)-cm1.92.32.7CTE(0-100oC)ppm/oC171424Young'sModulusGPa1208070TensileStrengthMPa290140150300kb300kbNowearwear-CONFIDENTIAL-KNOWLEDGEWearpatternforballbondandstitchbondwearisdifferent.BallbondformsawearringaroundthecapillaryCD.WedgebondwearstheOuterRadius(OR)andCDedgeWearRingaroundCDOuterRadiusandCDedgewearAfter300kbWearShapeRelatedtoBallBondvs.WedgeBondAfter300kb-CONFIDENTIAL-11KNOWLEDG