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ID:34933370
大小:1.98 MB
页数:7页
时间:2019-03-14
《SOS Wafer Cu Pillar Bumping Process Development for Flip Chip Package Application .pdf》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、SOSWaferCuPillarBumpingProcessDevelopmentforFlipChipPackageApplicationJohn,ZhiyuanYangPeregrineSemiconductor9380CarrollParkDrive,SanDiego,CA92121,USAjyang@psemi.comAbstractI/OMetalPadCupillarbumpingprocesshasbeendevelopedonSOSGlassSealing(SilicononSapphire)waferforflipchippackageapplicationSa
2、pphirewaferSapphirewhileintheinitialpackagingexperimentopenfailurehasbeenfound.Voidinginbumppadmetalhasbeenfoundinpackagefailureanalysis.ThecracksinitiatedfromtheBCBlayervoidinghavealsobeencaptured.Furtherinvestigationhasconfirmedthatthesurfaceroughnessofbumppadmetaliscloselyrelatedtothisfail
3、ure.ThevoidingwasformedforDepositandpatternalayerofBCBthatthebumppadmetalwasetchedawaybyplatingsolventUBMinbumpingprocess.Solutionsonprocessandbumpmetalstructuredesignhavebeendiscussedandpresentedwithevaluationexperimentresultsinthispaper.DepositUBM(UnderBumpMetallization)IntroductionTheCupil
4、larbumpingforSOSwaferisbasedonelectricalplatingprocess.(figure2).Sapphirewaferisre-passivatedbyBCBcoatingthenTi/CuisspatteredonasUBM(underbumpmetallization)aswellastheseedlayerforelectricalplating.Afterpatternedbythickphotoresister,theDepositandpatternalayerofphoto-resistwaferisplacedinelectr
5、icalplatingprocessforthefabricationofCupillarandSnAgsoldercapsection.Cuisfirstplatedandcontrolledtotheheightcloseto50umthenfollowedbyathinlayerofNiplatingthenfilledupwithSnAgsolderplating.Afterthephotoresiststrippingthewaferwillgothroughthereflowforsoldercapformation,thenfollowedbyCupillarand
6、LeadfreesolderplatingtheprocessofUBMmetalstrippingwithchemicaletching[1].ThisCupillarbumpingprocesscanalsobeusedforsolderbumpingbychangingtheheightofCupillarfrom50umtoabout10umandletthisshortpillarfunctionasUBMmetal.Therestsectionwillbefilledwithplatedsolder.Afterreflowsolderbumpingcanbeobtai
7、ned.TheinitialpackagingexperimentwascarriedoutbasedReflowandUBMmetalstriponflipchipontwolayerBTsubstratepackage.Fig2.CupillarbumpingprocessflowInpackagereliabilityevaluationtestfortheflipchipon2layerBTsubstratepackage,someopenfailureshavehapp
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