CMP化学机械研磨课件.ppt

HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,1,Chapter12ChemicalMechanicalPolishing,HongXiao,Ph.D.hxiao89www2.austin.cc.tx.us/HongXiao/Book.htm,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,2,Objectives,ListapplicationsofCMPDescribebasicstructureofaCMPsystemDescribeslurriesforoxideandmetalCMPDescribeoxideCMPprocess.Describemetalpolishingprocess.Explainthepost-CMPclean,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,3,Overview,MultilayermetalinterconnectionPlanarizationofdielectriclayersDepthoffocusrequireflatsurfacetoachievehighresolutionTheroughdielectricsurfacecanalsocauseproblemsinmetallization,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,4,ICFab,WaferProcessFlow,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,5,TungstenCMP,TungstenhasbeenusedtoformmetalplugsCVDtungstenfillscontact/viaholesandcoversthewholewafer.NeedtoremovethebulktungstenfilmfromthesurfaceFluorinebasedplasmaetchbackprocessesTungstenCMPreplacedetchback,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,6,P-Epi,P-Wafer,Metal3,AlCuAlloy,IMD3,USG,Metal4,AlCu,USG,SiliconNitride,AlCuAlloy,N-Well,P-Well,BPSG,n,+,n,+,p,+,p,+,STI,USG,W,AlCuAlloy,USG,M1,M2,AlCu,USG,W,IMD1,IMD2,TiSi2,Ti,TiNARC,W,Ti/TiN,Ti/TiN,SidewallSpacer,USG,PMDBarrierNitride,IMD3,Passivation1,Passivation2,PMD,CMPPSG,W,CMPUSG,W,CMPUSG,W,CMPUSG,W,CMPUSG,CMOSIC,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,7,DefinitionofPlanarization,Planarizationisaprocessthatremovesthesurfacetopologies,smoothesandflattensthesurfaceThedegreeofplanarizationindicatestheflatnessandthesmoothnessofthesurface,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,8,DefinitionofPlanarization,CompletelyConformalFilm,NoPlanarization,ConformalandSmooth,NoPlanarization,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,9,DefinitionofPlanarization,PartialPlanarization,GlobalPlanarization,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,10,DegreesofPlanarity,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,11,DefinitionofPlanarity,R,q,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,12,Planarization,SmoothingandlocalplanarizationcanbeachievedbythermalfloworetchbackGlobalplanarizationisrequiredforthefeaturesizesmallerthan0.35mm,whichcanonlybeachievedbyCMP,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,13,OtherPlanarizationMethods,ThermalflowSputteringetchbackPhotoresistetchback,Spin-onglass(SOG)etchback,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,14,ThermalFlow,DielectricplanarizationPre-metaldielectricHightemperature,1000CPSGorBPSG,becomesoftandstarttoflowduetothesurfacetensionSmoothandlocalplanarization,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,15,AsDeposited,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,SiO2,n+,n+,p+,p+,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,16,AfterThermalFlow,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,SiO2,n+,n+,p+,p+,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,17,EtchBack,ReflowtemperatureistoohighforIMDcanmeltaluminumOtherplanarizationmethodisneededforIMDSputteringetchbackandreactiveetchback,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,18,EtchBack,ArgonsputteringetchbackchipoffdielectricatcornerofthegapandtapertheopeningsSubsequentCVDprocesseasilyfillsthegapwithareasonableplanarizedsurfaceReactiveionetchbackprocesswithCF4/O2chemistryfurtherplanarizesthesurface,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,19,CVDUSG,USG,AlCuSi,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,n+,n+,p+,p+,SiO2,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,20,SputteringEtchBackofUSG,USG,AlCuSi,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,n+,n+,p+,p+,SiO2,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,21,CVDUSG,USG,AlCuSi,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,n+,n+,p+,p+,SiO2,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,22,ReactiveEtchBackofUSG,USG,AlCuSi,BPSG,P-typesubstrate,p+,p+,N-well,P-typesubstrate,n+,n+,p+,p+,SiO2,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,23,PhotoresistEtchback,PRspin-coatscanbakingPlanarizedsolidthinfilmonwafersurfacePlasmaetchprocesswithCF4/O2chemistryOxideetchedbyFandPRbyOAdjustingCF4/O2flowratioallows1:1ofoxidetoPRselectivity.Oxidecouldbeplanarizedafteretchback,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,24,AfterOxideDeposited,Oxide,Metal,Metal,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,25,PhotoresistCoatingandBaking,Oxide,Photoresist,Metal,Metal,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,26,PhotoresistEtchback,Oxide,Metal,Metal,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,27,PhotoresistEtchback,Oxide,Metal,Metal,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,28,PhotoresistEtchback,Oxide,Metal,Metal,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,29,PhotoresistEtchback,WhenFetchoxide,OwillbereleasedHigherPRetchrateduetoextraoxygenPRetchbackcantplanarizeverywellAfterthePRetchback,dielectricfilmsurfaceisflatterthanitisjustdeposited.Insomecases,morethanonePRetchbackisneededtoachieverequiredflatness,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,30,SOGEtchback,SOGreplacesPRAdvantage:someSOGcanstayonthewafersurfacetofillthenarrowgapsPECVDUSGlinerandcaplayerUSG/SOG/USGgapfillandsurfaceplanarizationSometimes,twoSOGcoat,cureandetchbackprocessesareused,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,31,SOGEtchback,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,32,NecessityofCMP,PhotolithographyresolutionR=K1l/NAToimproveresolution,NAorlDOF=K2l/2(NA)2,bothapproachestoimproveresolutionreduceDOFDOFisabout2,083for0.25mmand1,500for0.18mmresolution.HereweassumedK1=K2,l=248nm(DUV),andNA=0.6,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,33,NecessityofCMP,0.25mmpatternrequireroughness0.35mm,othermethodscanbeused,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,34,AdvantagesofCMP,PlanarizedsurfaceallowshigherresolutionofphotolithographyprocessTheplanarizedsurfaceeliminatessidewallthinningbecauseofpoorPVDstepcoverage,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,35,MetalLineThinningDuetotheDielectricStep,Metal1,Metal2,IMD1,PMD,SidewallThinning,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,36,PlanarizedDielectricSurface,noMetalLineThinningEffect,Metal1,IMD1,PMD,Metal2,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,37,AdvantagesofCMP,EliminatetherequirementofexcessiveexposureanddevelopmenttoclearthethickerphotoresistregionsduetothedielectricstepsThisimprovestheresolutionofviaholeandmetallinepatteringprocessesUniformthinfilmdepositionReducerequiredoveretchtimeReducechanceofundercutorsubstrateloss,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,38,PR,OverExposureandOverDevelopment,Metal2,Metal2,IMD1,PR,PR,Needsmoreexposureanddevelopment,PossibleCDlossduetomoreexposureanddevelopment,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,39,RoughSurface,LongOverEtch,Metal2,Metal2,IMD1,PR,PR,Needalongoveretchtoremove,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,40,FlatSurface,ShortOverEtch,Metal2,Metal2,PR,PR,Verylitteroveretchisrequired,IMD1,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,41,AdvantagesofCMP,CMPreducedefectdensity,improveyieldReducingtheprocessproblemsinthinfilmdeposition,photolithography,andetch.CMPalsowidensICchipdesignparametersCMPcanintroducedefectsofitsownNeedappropriatepost-CMPcleaning,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,42,ApplicationsofCMP,STIformationDielectriclayerplanarizationPMDandIMDTungstenplugformationDeeptrenchcapacitor,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,43,ApplicationsofCMP,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,44,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,45,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,46,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,47,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,48,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,49,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,50,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,51,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,52,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Polysilicon,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,53,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Polysilicon,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,54,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Polysilicon,Nitride,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,55,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Polysilicon,PadOxide,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,56,DielectricLayer,HeavilydopedSi,SiliconSubstrate,DeepTrenchCapacitor,Polysilicon,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,57,ApplicationsofCMP,Copperinterconnection.Copperisverydifficulttodryetch,Dualdamascene:processofchoiceTungstenplugisadamasceneprocess,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,58,ApplicationsofCMP,Itusestwodielectricetchprocesses,oneviaetchandonetrenchetchMetallayersaredepositionintoviaholesandtrenches.AmetalCMPprocessremovescopperandtantalumbarrierlayerLeavecopperlinesandplugsimbeddedinsidethedielectriclayer,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,59,PECVDNitride,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,Nitride,n+,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,60,PECVDUSG,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,Nitride,n+,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,61,PECVDEtchStopNitride,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,Nitride,n+,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,62,PECVDUSG,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,63,PhotoresistCoating,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,Photoresist,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,64,Via1Mask,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,65,Via1MaskExposureandDevelopment,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,Photoresist,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,66,EtchUSG,StoponNitride,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,Photoresist,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,67,StripPhotoresist,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,68,PhotoresistCoating,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,Photoresist,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,69,Metal1Mask,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,70,Metal1MaskExposureandDevelopment,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,USG,n+,USG,Photoresist,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,71,EtchUSGandNitride,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,Photoresist,USG,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,72,StripPhotoresist,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,USG,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,73,DepositTantalumBarrierLayer,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,USG,USG,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,74,DepositCopper,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,USG,USG,Copper,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,75,CMPCopperandTantalum,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,USG,USG,Cu,M1,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,76,PECVDSealNitride,P-Epi,P-Wafer,N-Well,P-Well,n+,STI,p+,p+,USG,W,PSG,n+,USG,USG,Cu,M1,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,77,CMPHardware,PolishingpadWafercarrierSlurrydispenser,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,78,ChemicalMechanicalPolishing,Slurry,PolishingPad,Pressure,WaferHolder,Wafer,Membrane,Platen,SlurryDispenser,RetainingRing,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,79,LinearPolishingSystem,Slurry,Pressure,WaferCarrier,Wafer,Membrane,SlurryDispenser,RetainingRing,PadConditioner,BeltandPolishingPad,SupportFluidBearing,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,80,OrbitalPolishing,DownForce,Slurry,Wafer,CarrierFilm,wc,OrbitalMotion,wp,PolishPad,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,81,PolishingPad,Porous,flexiblepolymermaterialcast,slicedpolyurethaneorurethanecoatedpolyesterfeltPaddirectlyaffectsqualityofCMPprocessPadmaterials:durable,reproducible,compressibleatprocesstemperatureProcessrequirement:hightopographyselectivitytoachievesurfaceplanarization,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,82,PolishingPadHardness,Harderpolishingpad:higherremovalrateandbetterwithindie(WID)uniformitySofterpad:betterwithinwafer(WIW)uniformity.Hardpadseasiertocausescratches.Thehardnessiscontrolledbypadchemicalcompositionsorbycellularstructure.,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,83,PolishingPad,CellsabsorbpolishingslurryFillerimprovemechanicalpropertiesPolishingpadsurfaceroughnessdeterminestheconformalityrange.Smootherpadhaspoorertopographicalselectivitylessplanarizationeffect.Rougherpadhaslongerconformalityrangeandbetterplanarizationpolishingresult,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,84,HardRoughPad,PolishingPad,Film,Wafer,PadMovement,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,85,SoftSmoothPad,PolishingPad,Film,Wafer,PadMovement,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,86,PadConditioning,PadbecomessmootherduetothepolishingNeedtorecreateroughpadsurfaceIn-situpadconditionerforeachpadTheconditionerresurfacesthepadRemovestheusedslurrySuppliesthesurfacewithfreshslurry,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,87,PolishingPadandPadConditioner,WaferCarrier,SlurryDispenser,PadConditioner,PolishingPad,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,88,PolishingHead,PolishingheadisalsocalledwafercarrierItconsistsofapolishingheadbodyRetainingringCarriermembraneDownforcedrivingsystem,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,89,PolishingHead,PolishingHeadBody,RetainingRing,CarrierMembrane,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,90,SchematicofPolishingHead,VacuumChuck,DownforcePressure,RestrainingRingPositioning,Wafer,RestrainingRing,RestrainingRing,Membrane,CarrierChamber,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,91,PadConditioner,SweepsacrossthepadtoincreasesurfaceroughnessrequiredbyplanarizationandremovestheusedslurryConditionerisastainlesssteelplatecoatedwithnickel-plateddiamondgritsDiabondCMPconditioner:stainlesssteelplatecoatedwithCVDdiamondfilmplateddiamondgrids,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,92,SurfaceofCMPConditioners,StainlessSteelPlate,NickelFilm,DiamondGrits,Conventional,StainlessSteelPlate,DiamondFilm,DiamondGrits(20mm),Diabond,SiliconSubstrate,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,93,CMPSlurries,Chemicalsintheslurryreactwithsurfacematerials,formchemicalcompoundsthatcanberemovedbyabrasiveparticlesParticulateinslurrymechanicallyabradethewafersurfaceandremovematerialsAdditivesinCMPslurrieshelptoachievedesiredpolishingresults,HongXiao,Ph.D.,www2.austin.cc.tx.us/HongXiao/Book.htm,94,CMPSlurries,CMPslurriesworkjustliketoothpasteChemicalskillgems,removetarta