关闭

关闭

关闭

封号提示

内容

首页 Process Considerations for Manufacturing 50 μm …

Process Considerations for Manufacturing 50 μm Thinned III-V Wafers.pdf

Process Considerations for Manu…

上传者: kukuka6 2012-07-25 评分 0 0 0 0 0 0 暂无简介 简介 举报

简介:本文档为《Process Considerations for Manufacturing 50 μm Thinned III-V Waferspdf》,可适用于人文社科领域,主题内容包含ProcessConsiderationsforManufacturingμmThinnedIIIVWafersGCobb,HIsom,CSelle符等。

ProcessConsiderationsforManufacturingμmThinnedIIIVWafersGCobb,HIsom,CSellers,VWilliamsTriQuintSemiconductorWRennerRdRichardson,TX,email:hisomtqscomKeywords:μmthinnedIIIVmaterial,backsideprocessing,mount,demount,manufacturability,saw,pickandplaceABSTRACT:DeviceperformancerequirementsforheatdissipationcontinuetodriveproductstothinnersubstratethicknessHowever,processingofwafersthinnedtoμmcreatesnewchallengesforhandlingthesefragilesubstratesBreakageofsubstratesduringmanufacturingcancreatesignificantexpenseandtheriskofdamageisincreasedasthenumberofstepsforbacksideprocessingincreasesTriQuintSemiconductorhassuccessfullydevelopedanddemonstratedaprocessformanufacturingdevicesonμmthinnedIIIVsubstratesThispaperfocusesontheprocesscontrolsandconsiderationsneededtomanufacturedevicesonthinnedsubstratesProcessconsiderationsatseveralpointsinthethinwaferflow(includingwafermounting,backsidemetallization,demountinganddiesingulation)willbediscussedWAFERMOUNT:DuetotheintrinsicbrittlenessofIIIVcompoundsemiconductormaterials,wafersmustbetemporarilybondedtoarigidcarrierwhilebeingprocessedthroughbackgrind,photolithography,metallizationandsubstrateviaetchstepsduringbacksideprocessingBondingcanbeachievedbyvariousmethods,suchasthermalorUVreleasefilm,waxorUVcuredopticaladhesiveWithallofthesebondingmethods,additionalprecautionsmustbetakentoensurethatthedevicesideofthewaferisprotectedfrombothchemicalandmechanicaldamageTriQuintSemiconductorutilizesaUVcurableopticaladhesiveandprotectivenegativeresistcoatingtobondwaferstoasapphirecarriersubstrateThenegativeresistcoatingmustbeofsufficientthicknesstocompletelycoverallfrontsidetopographysothattheopticaladhesivelayerdoesnotcontactanyofthefrontsidemetallizationDebondingisachievedbydissolvingthenegativeresistlayersince,oncecuredtheopticaladhesivebecomesvirtuallyinsolubleinsolventscommonlyusedinsemiconductordeviceprocessingWehavefoundthatthecuredopticaladhesiveisrequiredtokeepthethinnedwafersbondedtothesupportingsapphirecarrierduringthesubstrateviaplasmaprocessingBACKSIDEMETALLIZATION:Wafersthinnedtoμm,μmorlessbecomeincreasinglysusceptibletothestresseffectsofappliedthinfilmsThestressofepitaxialfilmscancausesignificantbowingofIIIVwafersafterthecarriersubstratehasbeendebondedfromthewaferIfnotaccountedandcompensatedfor,thisstresscanleadtoyieldlossduetowaferbreakageduringthewaferdebondingprocessorparametricyieldlossduetopoorthermalcontactduringelectricalprobeFollowingsubstrateviaformation,TriQuintSemiconductorsputtersacoatingofTiWNiAuthatactsastheseedmetalforthegoldplatingonthebacksideofthedeviceThestressinthislayerisadjustedtocompensateforcurvatureofthewaferinducedbytheepitaxiallayersThisadjustmentismadebyvaryingthedepositionpressureasseeninFigureBycarefultuningofthestressintheseedmetallayer,thecurvatureofthethinnedwaferisminimizedTiWStressvsDepositionPressurePressure(mTorr)Stress(mPa)Stress(mPa)FigureTiWfilmstressasafunctionofdepositionpressureWAFERDEMOUNT:Asindicatedbytheterminologyof“temporarybonding”,wafersmustberemovedfromthecarriersubstrateattheconclusionofbacksideprocessingThisdemountstepcanbethesourceofsignificantwaferbreakagewithμmthinnedsubstratesThedemountstepmustcompletelydebondthewafersfromthecarriersubstratewithnoresidueremainingonthewaferTriQuintSemiconductorhasdevelopedademountprocessthatconsistsofamultistepchemicalprocessthatdebondsthewaferfromsubstrateandalsoremovestheprotectiveresistlayeratthesametimeCSMANTECHConference,May,,Austin,Texas,USAAswithanychemicalprocess,thefirstconsiderationmustbetoselectchemicalsthatarecompatiblewiththesubstratewaferused,thematerialsdepositedduringthedevicefabricationprocessandthatcanbesafelyimplementedintothefabricationenvironmentSecondly,theprocessdevelopedmustberobustandminimizecycletimeTriQuintSemiconductorhasdevelopedadebondingprocessthatutilizeschemicalscommonlyfoundinsemiconductorprocessingThesechemicalsareusedtodissolvethesacrificialnegativeresistlayerappliedtothewaferspriortobondingthemtothesupportingsapphireusingtheopticaladhesiveAsstatedpreviously,theopticaladhesiveisnotnormallysolubleinthesechemicalsandremainsonthesapphiresupportswhichmustbecleanedinaseparatecleaningprocessWhendevelopingthedebondingprocessforμmthinnedwafers,itbecameapparentthattheturbulencegeneratedbynormalprocessinginoverflowweirtankswascausingwaferstocrackandbreakduringtheprocessAttemptstoadjusttheturbulencebyadjustingflowratesfailedtoimprovethedebondingresultsWefoundthatbafflingtheincomingflowresultedinasubstantialimprovementtothedebondingprocess(Figure)umDebondProcessRun#UnitsUnitFigureDIESINGULATION:DiesingulationmaybeachievedbyutilizingeitherwaferscribeandbreakmethodsorsawingTriQuintSemiconductorutilizesbothmethodsfordiesingulationforμmthinnedwafersThispaperwillfocusontheprocessconsiderationsforsawingμmthinnedwafersTapeselectionforthesawprocesswasdeterminedtobetheyieldlimitingcharacteristicinachievinghighyieldsatdiepickonμmthinnedIIIVsubstratesGreaterthandieyieldfrompickhasbeenachievedwithexcellentqualityafteroptimizationofthetapeselectionanddiepickprocessIndevelopingasawprocessforμmthinnedwafersitisimportanttoconsiderthephysicalnatureoftheprocessintermsofforcefromthesawblademovingthroughthematerial,thedepthofthecutintothesupportingtapeandthecoolingwaterbeingacceleratedacrossthewaferbythebladeTapemustbeselectedsothatdieareheldsecurelyduringthesingulationprocessbutcanbeeasilyremovedduringthediepickprocessaftersingulationDesignedexperimentswereconductedfocusingontapesfromvariousvendors(Table)tooptimizethediesingulationprocessTable:TapeDesignationAdhesiveThickness(μm)AdhesionaftercureAgmmBgmmCgmmOneexperimentallayoutandtheresultsofthetestarefoundinTableThefigureofmeritusedinthisexperimentwasthepercentageofdieexhibitingdefectsafterdiepickThebestresultswereobtainedusingtapeCwhichhasthethinnestadhesivelayerandlowestadhesionaftercureTable:TheseresultssupportatheorythatduringthesawprocesstheadhesiveispushedupintothesubstrateviaandissubsequentlyprotectedfromtheUVexposuretoreducethetackleveloftheadhesiveWhenattemptsaremadetoremovethedieatthepickprocessthishightackareacausesaplugofadhesivetobeleftinthesubstrateviaThereductioninadhesivethicknessminimizestheamountofhightackmaterialontheinteriorofthesubstrateviaandallowsfordietoberemovedwithoutresidualmaterialCSMANTECHConference,May,,Austin,Texas,USACONCLUSIONSDevelopingprocessesforIIIVsemiconductorwafersthinnedtoμmandbeyondposesanentirelynewrealmofdifficultiesasthinfilmeffectsbegintodominatetheintrinsicstrengthofthesubstratematerialSpecialconsiderationsmustbetakenwithregardstostressmanagementofdepositedfilmsandtothestressinducedbythechemicalandmechanicalprocessingthatmustbedonetoproducethefinaldevicesAsdeviceperformancerequirementscontinuetodrivesubstratethicknesstoprogressivelysmallersizes,newprocessdevelopmentwillfollowtoallowformanufacturabilityofthosedevicesACKNOWLEDGEMENTSTheauthorswouldliketothankthefollowingindividualsfortheirsupportincompletingthetestingandexperimentationrequiredforthisproject:GlenBronson,DrAndrewMacInnes,RodneyBrownandJamesMillerACRONYMSUV:ultravioletCSMANTECHConference,May,,Austin,Texas,USACSMANTECHConference,May,,Austin,Texas,USAOMNIBLANK:

用户评论(0)

0/200

精彩专题

上传我的资料

每篇奖励 +2积分

资料评价:

/4
0下载券 下载 加入VIP, 送下载券

意见
反馈

立即扫码关注

爱问共享资料微信公众号

返回
顶部