WET工艺介绍

WET 工艺 钢结构制作工艺流程车尿素生产工艺流程自动玻璃钢生产工艺2工艺纪律检查制度q345焊接工艺规程 介绍LNWetCleaning(Pre-treatment)WetCleaning(Post-treatment)ResistRemovalDiffusionCVDPVDLithographyEtchingDopingWaferInWaferOutICProcessingWetProcess1.FEOLpost-ashclean35%- typicalSPM.- trendistointegrateresiststripingandcleaning.2.Pre-diffusionclean30%- RCAclean- trendistousedilutechemistriestoreducecost,improveequipmentreliabilityandprocessperformance.3.BEOLpost-etchclean20%- issueswithtechnical,cost,environment- trendistousesinglewaferdryclean4.Others(PostCMPandspecialcleaning)15%- SC1basedcleaningChemicalsInvolvedWetbenchPurposeofPre-cleanistoremovethelastunwantedoxidelayerandpreparesurfacefreeofmetalliccontaminantsandgoodPCfornextoxidation.Pre-diffusionclean-RCAcleanSiO2(s)+6HF(l)®H2SiF6(l)+2H2O(l)Theetchrate(orreactionrateofHFwithoxide)canbeslowedbyaddingmorewaterandlowerstheconcentrationofHF.HFwilletchBPSG>>Oxide>>Nit>>SiH2O:HF100:1(50:1,49%)Function:RemoveOxide(SiO2)Mechanism:ReactswithOxideandformasolvablebyproduct.OxideEtchHFEtchingoffnativeoxideleavinghydrophobicSisurface,repelsH2O,thatispronetoH2OmarkAsamethodtopassivatesurface,H2O2/SC1/SC2lastisused.AftercleaningHFonSi,theSiwaferhasH2SiF6=>itischargedupwithSiF62-ions=>thishashighaffinitytoattractdefects,duetostrongpolarity.WhatisH2Omark?ItissomeH2OstainwhichoxidisestheSisurface.ItcanalsobeaconcentrationofH2Ocontaminants.H2Oattractedarea®easytocreateH2OmarkoxoxSiwaferWhatistheimpactofwatermark?Watermarkcancauseproblemswithadhesionoffilms,contactresistance,non-uniformitybetweenconductinglayers,blocketch,gateoxidedefects.Howtopreventit?Treatthewafersurfacewitheg.H2O2,SC1,SC2(someoxidationeffects)toensurehydrophilicsurfacethroughout.EnsuredryersperformanceVaporJetdryerLowpressureDryerSpinDryerMicroMistDryerDIwaterisDe-ionizedwater.WaterRinse:DIWaterDIWtankisforrinsingwaferascleanaspossiblebeforegoingintothenextchemicaltanktopreventcross-contaminationorbeforeleavingthehood.DIWcanoverfloworquickdumprinse(QDR).OverflowisverystableflowofDIWandgivesgoodPCcontrol.Itmakesuseofdiffusionanddilution.QDR,ontheotherhandmakesuseofextradragforcewhenDIWdump&itisfastatremovingacidtrace,butsincethereismoreagitationinthetank,itmayresultinhigherPC.ControloftheDIWtankandsurroundingcleanlinessisimportant.DIWtankoverflowsatalltimeswithby-passflowtopreventbacteria.BacteriawillresultinPC&metalliccontamination.DIWTankDIWcanbehotorcold-dependsonpreviousandnexttanks.HotChemicalwillbefollowedbyHotDIW/ColdDIW;thisistopreventthermalshock.Forhighviscositychemical,HDIWrinsewillimprovesolubilityofthechemical,thusimprovethediffusionofchemicaltobulkofDIW,thisimprovestherinseefficiency.ThereisalsotheDIWMegasonicTank(overfloworwithquickdumprinse).TheextraMegasonicpowerhelpsparticlereductionandimprovesrinsingefficiencyespeciallyforviscouschemical.DIWTankDIWflow-rate.ProcessTime.DumpCycle&ProcessTimeforeachsequence.MegasonicOnSequence.CriticalParameters30C,NH4OH:H2O2:H2O(1:2:50)Function:Particleremoval,LightpolymerremovalMechanism:oxidationandelectricalrepulsionOxidationDissolutionSurfaceetchingElectricalrepulsionOxidationmechanismElectricalrepulsionmechanismParticlecleanSC1(Standardclean1)SC1withMegasonicTransducerTransducerTransducerPartialwettingSolventdiffusingatinterfaceTotalwettingFloatingfreeBenefit:enhancetheparticleremoverate.Drawback:H2O2willbereducedduringoperation,whichcausesurfaceroughness!ThemechanismproducingtheroughsurfaceistheNH4OHactsastheetchantoftheoxidewhileH2O2actsastheoxidant:SurfaceMicro-roughnessSi<>H2SiO42-(H3SiO4-,HSiO43-etc)V1V2HO2-OH-Path-1Path-2OH-V3V1=k1{HO2-}3k1=1.2x1014(65C)V2=k2{OH-}k2=5970(65C)V3=k3{OH-}2k3=2.0x109(65C)Path-1Path-2SiSubstrateMethodsofreducingthemicroroughnesscanbesummarizedas:ReducetheproportionofNH4OH(theetchant)ReducethetemperatureofthebathReducethecleaningtimeConventionalSC1:(1:1:5),70~80CNH4OHevaporate&H2O2decomposeswithusageandtimeNH4OHlostinonehour:32%at50℃;44%at70℃H2O2decompositionisastrongfunctionofmetalioncontentSC1BathLifeProblems:HeaterBurnt-InlineheaterismadeofQuartzandSC1etchesSi,thusinlineheaterhaslifetime.Ifburntandleaking,therecanbemetalcontaminationslikeALandFe.NH4OHandH2O2willdegradeandcausebubbling,mayresultinstreakdefectsonthewaferCommonIssueswithSC1Togetridofbubbles:Tiltwafertofacebackm/c.Slightagitationofwaferstoreleasebubblefromwafersurfacem/c.Bubblecollapser/degaser.PFBubbleDegasserfilterPumpinOuterweirfilteredliquidBubbleDegaserCommonIssueswithSC130C,HCl:H2O2:H2OFunction:IonicandMetallicContaminationRemovalMetalliccleanSC2(Standardclean2)Mechanism:HCLreactswithmetaltoformasolublesaltwhichisremovedfromwafersurfacebydissolvinginH2O.AsfarasH2O2,itpassivitytheactivesurface.HCl&H2O2arenoteasytobeproducedtobeultracleanandassuch,thechemicalitselfhavesomemetallic.WhendilutedSC2isused,metallicfromwafercanstillberemovedandthechemicalalsohaslessmetallictodepositonthewafer.Thisisthebestscenario.Note-Cleanupisnotalwaysremovingdefects/contaminants;itdependson"who'isdirtier-Diffusionprinciple:movementofsolutesfromhigherconcentrationtolowerconcentrationuntilequilibrium.ProblemwithSC2DryerIsopropylAlcohol(IPA)Function:removeswaterfromwafersMechanism:AlcoholvaporsdisplacewaterfromsurfaceThealcoholevaporatesmoreeasilythanwater.ItleavesadrysurfaceCleaningHF+H3PO4(PhosphoricAcid)Function:AAnitridestripaftergrowingisolationoxideNitrideRemoveNitrideetchrateinH3PO4At1600C,H3PO4is87%atboilingpoint.Originalchemicalconcentration=86%Asthechemicalheatsup,DIWspikesintomaintainchemical%->boilsat1600C->optimaletchrateSMSDIWspikeSESBestProcessControl–NISSOSystem.DIWspikeDIWspikeOldDNSMayresultinwafercrossslotduetowatersuperboil.DIWspikingpositionandcontrolarecriticalforoptimalprocess.NitrideRemoveMechanism:Si3N4+6H2O-------->3SiO2+4NH3(H3PO4ascatalyst)ERA/minSiConc.(ppm)Particle(#/ml,@0.2um)SiNSiO2ParticleNitrideRemoveWhentheSiliconcontentisveryhigh,oxideetchratedecreases.Siliconmayevenre-depositonwaferandtrapsomeH3PO4.IfthisPhosisimplanted/drivenintothewafer,itwillgiveextra“n〞typewhichmayleadtoleakyFieldOxideandpoorGOI.Inordertostabilizetheetchlossofoxide,forthe2H3PO4tankprocesstime,Tank1timeissettoremovealltheNitridewhileTank2takescareoftheoveretch.Asaresult,theTank2oxideetchrateismorestablewhichleadstobetteroxideremainscontrol.Oxynitride/oxideAASiN100APadOxideHFdipAASiN100APadOxideHPO1100APadOxideHPO2AASiNStripProcessforCM71DRAMPadOxideRemainedHPOlifetimedependent!(RecipeNLH240AHPO2550ASC1M)SPM(SulfuricPeroxideMixture)98%H2SO4:30%H2O2=5:1,125CCaro’sacid/SPM/PiranhaFunction:Photo-resiststrippingOrganiccontaminationremovalMechanism:H2SO4+H2O2HO-(SO2)-O-OH+H2OHO-(SO2)-O-OH+-(CH2)nCO2+H2OUsehotQDR(QuickDumpRinse)withmega-sonictorinseoffviscousH2SO4onwafersRecipeforPRStripNDH10APRRMM:DHF(100:1)15〞+SPM5’+SPM5’+HQDR(withMega)NPRRM:SPM5’+SPM5’+HQDR(w/oMega)BOE(BufferedOxideEtch)23C,Mixtureof40%NH4Fand49%HFSMICdefineMB:BOE(10:1),LB:BOE(130:1:7),DB:BOE(200:1)SurfactantsareoftenaddedtoimprovewettingBenefitcomparedtoDHF:1)LowselectivityoxideetchforDRAMcontactpre-clean2)PreventphotoresistliftoffforKV,DualgateprocessForBOEetchwithPRonwafers,S/DorMarangoniisusedfordryingSiO2/BPSGetchingmechanismSiO2ismainlyetchedbyHF2-SiO2+2HF2-+2H3O+SiF4+4H2OSiF4+2HFH2SiF6(inHFsolution)SiF4+2NH4F(NH4)2SiF6(inBOEsolution)BPSGismainlyetchedbyHFB2O3+6HF2BF3+3H2OBPSG/SiO2etchingselectivitycontrolNH4F,BPSG/SiO2NH4FNH4++F-HFH++F-K1=[H+][F-]/[HF]=0.00068HF+F-HF2-K2=[HF][F-]/[HF2-]=0.193NH4Fconcentration(mol/Kg)Etchrateat25C(A/min)DHFpre-cleanforPolydepOxideAOxideBOxideCACT940isusedtoremovePlasmacuredphotoresistHardcrestofside-wallpolymerCl-ionstrappedintheside-wallpolymer/photoresistO3/plasmaAshingPRS+PRS(photoresiststrip)PSR(Poststripperrinse)DIW(dryer)PlasmaAshing:removehard-curedphotoresist(95-99%)PRS:removeside-wallpolymerbyreductiveetchwithNH2OH(HDA-HydroxylAmine)*PRS=ACT-690C;ACT-940;EKC-265;EKC-270,etc.PSR:neutralizeamines;minimizeOHinducedcorrosioncausingbyunevenmicro-etchinDIwaterrinse*PSR=NMP,IPA,etc.(PRS)ACT940Solvent(1)MetaletchpostcleanVIAEtchpostcleanOtherWetEtchChemicalsinSMICSC1(NH4OH:H2O2:H2O=1:1:1)/24C30~40min:TiSelectiveEtchSC1(NH4OH:H2O2:H2O=1:1:5)/50C5min+:CoselectiveetchM2(H3PO4:HNO3:CH3COOH~70:2:12)/75C20min49%HF,HF(20:1):OxidereclaimPolyetch(HNO3:HF=6:1)/23C:PolyreclaimSC1(NH4OH:H2O2:H2O=1:1:5)/50C:WMetalreclaimSPM(H2SO4:H2O2)=5:1/125C:Al/Cu,Ti,TiNMetalreclaimDryerIntroductionDryerisusedtoensurethattheDIWonthewaferisnotevaporatedbuteitherdisplacedorphysicallyremoved.PresentlytherearefollowingtypesofdryersinFab7Spindryer(S/D)VJD(VaporJetDryer)LPD(Lowpressuredryer)MMD(MicroMistDryer)SpinDryerOn-CentreTypeOff-CentreTypeCriticalParameters:–TransferTime(On-centrefaster)RampupspeedMaxspeedProcessTimeExhaustIonizerStandardVapourDryerEithermadeofQuartzorStainlessSteel.IPACondensateDrainPlateHeatTransferAdhesiveHeaterBlockIPACriticalParameters:WafertransfertimefromF/Rtobaseofdryer<13sIPArecoverytime<<30sIPAvapourtemp>78oCafter30sec.IPADIW%<0.5%HeaterTempHeatTransferAdhesionF/RtoresistivityRobotarmup/downV/D–mayresultinPCIPAlevelsensorbox–mayresultinPCPrincipleofMarangoni®DryingOperatingtemperatuer:RTProcesstime7-10minIPAconsumptionappr.4-10ml(50Wafers6〞/8〞)DIwater/run80-100lNitrogen/run120-180lIPApeakconcentrationinDIwater~30ppmDiffusionofIPAinWaterIPAConcentrationA>B(MeniscusGeometry)IPADecreasesSurfaceTensionSurfaceTensionA