介電化學(xué)氣相沉積

PDCVDReactorsFutureTrendsofDCVDPAprocessinwhichthegaseousprecursorhasachemicalreactiononthewafersurface,depositingasolidbyproductonthesurfaceasalayerofthethinfilmTheotherbyproductsaregasesthatleavethesurface(referredtoaspyrolysis).Allmaterialforthethinfilmissuppliedbyanexternalsource.ThereactantsinaCVDprocessmuststartoutinthevaporphase(asagas).AmaterialthatconductsnocurrentwhenvoltageisappliedtoacrossOxide(SiO2)andNitridesare P PTypesofCVDChemicalPDielectricsinULSIPDielectricsin0.15umULSIMicrographcourtesyofIntegratedCircuitPMultiLayerPDielectricformulti-metal-connect(PMDorIMD).Electricalisolationbetweentransistors.(shallowtrenchisolation,STI)GatespacerforLDDimplantation.(TEOS/SiNcompositePassivationdielectriccap(Si3N4)Anti-reflectivecoating-ARC(SiON).DielectricsinULSIWCVD(thermalCVD)PlasmaPMD(ILD),IMD,TEOS-Spacer,PE-SiNP CVD(ChemicalVaporCVDCVDfilmsandtheirgassourceinIC WSi2WF6,SIH4, PCVDFilmsin Si(OC2H5)4(TEOS);TEOS+O2;TEOS+O3; SiOxNySiH4+N2O+N2+NH3;SiH4+N2+NH3 Si3N4SiH4+N2+NH3;C8H22N2Si(BTBAS)Epi-SiSiHCl3(TCS);SiCl4;SiH4+O3;SemiconductorPoly-SiSiH4;DCS PFundamentalofPSiliconThinfilmsareverythininPPGaseousbyproductsdiffuseacrosstheboundaryonthesurfaceonthesurfaceReactontheNucleation:PSchematicofSchematicofCVDTransportandReactionStepsofreactantsDiffusionofintosubstrate6)Surface PGasFlowinGasReactionDepositedSiliconPGasGasFlowDynamicsattheWaferGasGasBoundaryStagnantPBoundaryLayeratWaferContinuousgasDepositedSiliconPXiulanCheng/FigurePGoodelectricalGoodthicknessControlledstoichiometries(化學(xué)計(jì)量ThinFilmPThemovabilityofReactiveradicalonsubstratePrecursorsgaschemicalperformance.WafersurfacetemperaturePlasmaEffectofsurfaceHighmobilityperfectstepcoverageandgapfillingSurfaceMobilityofPHigherarrivingSidewallcoverage=b/aBottomcoverage= Aspectratioh/wHigherarrivingangleθandsurfacemoreperfectthegapfillingcapability,thestepcoverageandUniformPConformalstepNonconformalstepStepCoverageandAspectAspectRatio500 AspectRatio250 250PAspectRatioforFilmBadgapfillingcapabilityvoidP(Phigharrivingangle.PlasmaenhancementhighersurfacePrecursorswithhighersurfacemobility,suchasO3-TEOS,W-CVD.Deposit/etch/depositprocessorHDP-CVDprocess:Ar+sputteringetcheliminatetheoverhangimprovethearrivingangle.PWhenprecursorspassthroughboundarylayerandarriveatsubstratesurface,theycanbeabsorbedonthesurface.SurfaceabsorptionChemisorption(chemicalChemicalbondwillbeformedbetweenthemolecularofsubstratesurfaceandthemolecularofTheabsorptionenergyofthechemicalbondisaboutGenerally,forIMDCVDdeposit,thedeposittemperaturecannot>450C(~400C0.06eV)duetothelimitationofAllinecannotbreakthechemicalbondtoreleasetheprecursors.But,inplasma(e.g.PECVD),ionbombardmentinplasmacanprovide10~20eVenergytobreakthechemicalbondandthenreleasetheprecursorstomoveonthesurfaceofsubstrate.Physisorption(PhysicalPrecursorsareabsorbedonthesurfaceofsubstratebytheforce(suchasVanDerWaalsforce,Dipole-dipoleforce,)whichismuchlowerthanthatofchemicalabsorption,Theabsorptionenergyofphysisoptionislowerbothlowerthermalenergy(~400eV)orplasamenhancementcandesorbtheprecursorstomoveonthesurfaceofsubstrate.BondingBondingThedistancefromthePrecursorswithphysicalPrecursorswithchemicalPPTEOS(正硅酸乙脂，SiSiH4MainDCVDPC.R.=Ae-E/EaisactivatingDepositrateofCVDDependonthechemicalreactionrate(C.R.),diffusionrateofprecursorinboundarylayer(D),andtheabsorptionratio.TheKineticsofCVD(CVD動(dòng)力學(xué)D.R.C.R.[B].[C][B]and[C]istheabsorbedprecursors’s(reactiononsurfaceinnotenough.).D.R.Ddn/dxThedepositionrateismainlycontrolledbythemasstransportofprecursorsintheboundarylayer.Willcreatealargeamountofparticlestocontaminatethewaferandreactionchamber.Gas-phasenucleatonIPPFormostofCVDprocessofsingle-waferreactive–Mass-transport-limitedregion.SinceflowrateismucheasiertobecontrolledthanHelptogeneratemorereactiveEffectofPlasmainPrefractiveindex,n=lightspeedinlightspeedintheFor633nmPRRRRe=tanye=tanycosn,k,n2,kcost,n,PFor2layerI(l)=f(n1,k1,t1,n2,k2,t2,ns,PThicknessMeasurementPDepositionrateDepositionPWERCVDWERthermal-growthSiO2WetEtchingRateandWetEtchingRateRatioGaussianGaussian(orNormal) PPShrinkage=ThicknesschangeafterthermalP-NU(%)=Gaussian(orNormal)NU(%)=Non-uniformity(x-x)2+(x-x)2++(x-Standardnx=x+x++BasicAverageofmeasuredP49PointContour7315 9Point-Quick TestDiameter5Point-QuickDifferentPrometrixMapping PPWhatdoes4%non-uniformityPradiusofcurvatureafterdepositionsubstratethickness(mm)filmthicknessradiusofcurvaturebefore1tR2RYoung’sModulusofthesubstrateEh6t1-1= Measurementofstressin MeasurementMeasurementofstressinNeedmeasurePPDCVDMainMainTypesofDCVDP CVDReactorContinuousCold-wallPressure(Torr)Temp.(℃)Pressure(Torr)Temp.(℃)Pressure(Torr).PDCVDProcessP–Especially:O3-TEOSdepositSiO2:UsedinSTIandPMDfor0.25~0.35umN2 ProcessN2TranfrrinCleaningassemblyOftransferringPAPCVDAPCVDAPCVDReactantgasInertReactantgas(a)Gas-injectionNN(b)PlenumPPComparisonwithPE-P45-28nmTEOS+O3SACVDAR10:1 AssistedEtchSub65nm(<65nm,e.g.45nm)Sub65nmSTIPApplication:usedinFEOLduetohigherPressure:0.1~1Torr;midtemperature.Equipment:Furnaceformassproduction.Reactionmode:LowPressureCVDOxideOxideDepositionwithTEOSNPofOxides,Nitrides,orPolysiliconThree-zoneheatingPressureExhausttoGasSpikethermocouples(external,PPlasmaPlasmaAssistedLowerprocessingtemperature(250–450°C).Excellentgap-fillforhighaspectratiogaps(withhigh-densityplasma).Goodfilmadhesiontothewafer.Highdepositionrates.HighfilmdensityduetolowpinholesandLowfilmstressduetolowerprocessingP1)ReactantsenterRF2)Dissociation7)Desorptionof8)By-productareformed5)Precursordiffusion6)SurfacePPMass-transport-limitedRFShowerPPECVDPXiulanCheng/FigureGeneralSchematicofPECVDDeposition-SiO2Si3N4SiONDepositiontemperature(700–300–StepStressat23Consilicon12–18x1–8x(tensileorPHighDensityPlasma(HDP)isatypeofadvancedchemicalvapordeposition(CVD)technologyinwhichthedensityofplasma(~10-10n/cm3)ishigherthanthatusedtheinconventionalplasma-enhanced(PE)CVDtechnology.HDP-CVDisconsideredaleadingtechnologyforthemostadvancedgap-requirementsin<0.35μmdesignPrincipleofHDPSilaneoxidedepositingandargonionetchingbackatthesameWhendepositionandsputterrateareproperlyadjusted,theHDPchamberandprocessiscapableoffillingnarrowgapsfromthebottomupwithoxideofhighqualityandspatialuniformity.Gap-fillingcapabilitydependentonratioofdepositiontosputtering.Deposition/sputterratio:HighDensityPlasmaCVD(HDP-PEffectofD/SonthedepositionToollittlesputtering(toolargefillingresultinginvoid.Oversputtering(toosmallEquilibriumbetweendepositonandsputteringatthecornerPHDPCVDPPhotographcourtesyofAppliedMaterials,UltimaHDPCVDHighDensityPlasmaDepositionEffectofEffectofRespectRatioonHDP-CVDPPControltheplasmaenergyadjuststressinNovellusC2-SpeedHDPAMATUltimaHDPControltheplasmaHDP-CVDReactionPNovellusC2-PDCVDThermalsaline-baseThermalsaline-baseCMPstoplayerforSTIpocessSiH42O2SiO23SiH44NH3Si3N4PThermalCVDPPMD:mainlyuseO3-TEOSmode.Spacer:mainlyuseO3-TEOSmodeThermalTEOS-baseSi(OC2H5)4O2SiO2byproductsorSi(OC2H5)4O2SiO2Doping:B(OCH3)3O2B2O3byproductsP(OCH3)3O2P2O5byTEOSO3SiO2byproducts(perfectconformabilitygpgpy)Doping:O3TEBTEPOTEOSBPSGbyproductsThermalCVDLinerPPFSGAexampleofPECVDSiO2withSiH4 2TotallyforSiOdeposition,SiH+NOplasmaSiOH+HO+N+NHSaline-baseGas:SiH4+N2OSiO2,SiH4+NH3+N2e-+NOfie-+O+e-+SiHfie-+SiH+HSiH+OfiSiO2+PlasmaEnhancedCVDPProcessPSi-HcouldabsorbUV.LetUVpassthrough.(n=1.7~1.8)PMDbottomSi3N4barrierForsmallerandsmallerIC,itismorediffcultforLPCVDSiNtousenPMDbottombarrierlayerduetothermalbudgetlimitation.(700~900CitisgraduallysubstitutedbyPECVDSiNwithlowtemperature(550C).(butwillinduceplasmadamage)remoteplasmaCVDprocess.DARClayer(dielectricanti-reflectivecoating)SiOxNy(~300A)forAlCulinephotolithography.SiH4/N2Oration;RFpowerandpressureabsorptionratiokPPE-TEOSHasperfectstepcoverageandconformability.PPSTIPPALDisaCVDprocessbasedonsequential,self-limitingreactionsLayerEpitaxy)90’ssemiconductorexceptionalconformalityonhigh-aspectratiostructures,thicknesscontrolattheAngstromlevelunablefilmPSelflimitingOnecyclerestorestheoriginalALDPALDPALDPALDDepositingPALDPALDPFastvalvesforgaspulseswitchingFastSeparationofthereactantsSeparationoftheUHV:pumpsawayunreactedprecursorandby-productsbymolecularflow;slow,allowsLEED,AES,XPSetc.PurgeGas:theviscousflowofaninertgaspullsawaytheunreactedprecursorsandby-products.Itisusedforproductionpurpose.GasflowreactorALDPNewConceptsofPALDvs.CVD/PPSiH4-basePECVDPPPofPDelaytime(10-9PSi3N4(k~7.0)orSiOxNy(k=3.9~7.0)withNeedsuperthinoxidebufferTiO2:k~80BST:HighkdielectricPReductionRCRCRCDelayandLowkPLowkForUSG:k=40~42;FSG:k=35~38Advancedlowk Amorphousα-FCWhatarestepcoverage,conformability,aspectratio,andTheeffectofarrivingangleandsurfacemobilityonstepcoverageinDCVD.PlsgivefewmethodstoavoidvoidinDCVDprocess.Fromsurfaceabsorptiontypeandstickingcoefficient,explainthedifferenceofgapfillingcapabilitybetweenSiH4-baseandTEOS-basereactantinDCVD.BrieflyexplaintheeffectoftemperatureondepositionrateofDCVD(threeexplanations)andthereasonwhyplasmawidelyusein