Michael quirk_半导体制造技术-第11章_淀积.ppt

,SemiconductorManufacturingTechnologyMichaelQuirk&JulianSerdaOctober2001byPrenticeHallChapter11Deposition,Objectives,Afterstudyingthematerialinthischapter,youwillbeableto:1.Describemultilayermetallization.Discusstheacceptablecharacteristicsofathinfilm.Stateandexplainthethreestagesoffilmgrowth.2.Provideanoverviewofthedifferentfilmdepositiontechniques.3.Listanddiscussthe8basicstepstoachemicalvapordeposition(CVD)reaction,includingthedifferenttypesofchemicalreactions.4.DescribehowCVDreactionsarelimited,reactiondynamicsandtheeffectofdopantadditiontoCVDfilms.5.DescribethedifferenttypesofCVDdepositionsystems,howtheequipmentfunctionsandthebenefits/limitationsofaparticulartoolforfilmapplications.6.Explaintheimportanceofdielectricmaterialsforchiptechnology,withapplications.7.Discussepitaxyandthreedifferentepi-layerdepositionmethods8.Explainspinondielectrics.,FilmLayersforanMSIEraNMOSTransistor,Figure11.1,ProcessFlowinaWaferFab,Figure11.2,Introduction,FilmLayeringinWaferFabDiffusionThinFilmsFilmLayeringTerminologyMultilayerMetallizationMetalLayersDielectricLayers,MultilevelMetallizationonaULSIWafer,Figure11.3,MetalLayersinaChip,MicrographcourtesyofIntegratedCircuitEngineering,Photo11.1,FilmDeposition,ThinFilmCharacteristicsGoodstepcoverageAbilitytofillhighaspectratiogaps(conformality)GoodthicknessuniformityHighpurityanddensityControlledstoichiometriesHighdegreeofstructuralperfectionwithlowfilmstressGoodelectricalpropertiesExcellentadhesiontothesubstratematerialandsubsequentfilms,SolidThinFilm,Figure11.4,FilmCoverageoverSteps,Figure11.5,AspectRatioforFilmDeposition,Figure11.6,HighAspectRatioGap,PhotographcourtesyofIntegratedCircuitEngineering,Photo11.2,StagesofFilmGrowth,Figure11.7,TechniquesofFilmDeposition13,Table11.1,ChemicalVaporDeposition,TheEssentialAspectsofCVD1.Chemicalactionisinvolved,eitherthroughchemicalreactionorbythermaldecomposition(referredtoaspyrolysis).2.Allmaterialforthethinfilmissuppliedbyanexternalsource.3.ThereactantsinaCVDprocessmuststartoutinthevaporphase(asagas).,ChemicalVaporDepositionTool,PhotographcourtesyofNovellus,SequelCVD,Photo11.3,CVDChemicalProcesses,1.Pyrolosis:acompounddissociates(breaksbonds,ordecomposes)withtheapplicationofheat,usuallywithoutoxygen.2.Photolysis:acompounddissociateswiththeapplicationofradiantenergythatbreaksbonds.3.Reduction:achemicalreactionoccursbyreactingamoleculewithhydrogen.4.Oxidation:achemicalreactionofanatomormoleculewithoxygen.5.Reduction-oxidation(redox):acombinationofreactions3and4withtheformationoftwonewcompounds.,CVDReaction,CVDReactionStepsRateLimitingStepCVDGasFlowDynamicsPressureinCVDDopingDuringCVDPSGBSGFSG,SchematicofCVDTransportandReactionSteps,Figure11.8,GasFlowinCVD,Figure11.9,GasFlowDynamicsattheWaferSurface,Figure11.10,CVDDepositionSystems,CVDEquipmentDesignCVDreactorheatingCVDreactorconfigurationCVDreactorsummaryAtmosphericPressureCVD,APCVDLowPressureCVD,LPCVDPlasma-AssistedCVDPlasma-EnhancedCVD,PECVDHigh-DensityPlasmaCVD,HDPCVD,CVDReactorTypes,Figure11.11,TypesofCVDReactorsandPrincipalCharacteristics,Table11.2,Continuous-ProcessingAPCVDReactors,Figure11.12,ExcellentStepCoverageofAPCVDTEOS-O3,Figure11.3,PlanarizedSurfaceafterReflowofPSG,Figure11.14,BoundaryLayeratWaferSurface,Figure11.15,LPCVDReactionChamberforDepositionofOxides,Nitrides,orPolysilicon,Figure11.16,OxideDepositionwithTEOSLPCVD,Figure11.17,KeyReasonsfortheUseofDopedPolysiliconintheGateStructure,1.Abilitytobedopedtoaspecificresistivity.2.Excellentinterfacecharacteristicswithsilicondioxide.3.Compatibilitywithsubsequenthightemperatureprocessing.4.Higherreliabilitythanpossiblemetalelectrodes(e.g.,aluminum)5.Abilitytobedepositedconformallyoversteeptopography.6.Allowsforself-alignedgateprocess(seeChapter12).,DopedPolysiliconasaGateelectrode,Figure11.18,AdvantagesofPlasmaAssistedCVD,1.Lowerprocessingtemperature(250450C).2.Excellentgap-fillforhighaspectratiogaps(withhigh-densityplasma).3.Goodfilmadhesiontothewafer.4.Highdepositionrates.5.Highfilmdensityduetolowpinholesandvoids.6.Lowfilmstressduetolowerprocessingtemperature.,FilmFormationduringPlasma-BasedCVD,Figure11.19,GeneralSchematicofPECVDforDepositionofOxides,Nitrides,SiliconOxynitrideorTungsten,Figure11.20,PropertiesofSiliconNitrideforLPCVDVersusPECVD,Table11.3,HighDensityPlasmaDepositionChamber,PhotographcourtesyofAppliedMaterials,UltimaHDPCVDCentura,Photo11.4,Popularinmid-1990sHighdensityplasmaHighlydirectionalduetowaferbiasFillshighaspectratiogapsBacksideHecoolingtorelievehighthermalloadSimultaneouslydepositsandetchesfilmtopreventbread-loafandkey-holeeffects,Dep-Etch-DepProcess,Figure11.21,FiveStepsofHDPCVDProcess,1.Ion-induceddeposition2.Sputteretch3.Redeposition4.HotneutralCVD5.Reflection,HDPCVDwithWaferatThroatofTurboPump,Figure11.22,DielectricsandPerformance,DielectricConstantGapFillChipPerformanceLow-kDielectricHigh-kDielectricDeviceIsolationLOCOSSTI,3-PartProcessforDielectricGapFill,Figure11.23,PotentialLow-kMaterialsforILDofULSIInterconnects,Table11.4,InterconnectDelay(RC)vs.FeatureSize(m),Figure11.24,TotalInterconnectWiringCapacitance,RedrawnwithpermissionfromSemiconductorInternational,September1998,Figure11.25,Low-kDielectricFilmRequirements,Table11.5,GeneralDiagramofDRAMStackedCapacitors,Figure11.26,ShallowTrenchIsolation,PhotographcourtesyofIntegratedCircuitEngineering,Photo11.5,Spin-onDielectrics,Spin-onGlass(SOG)Spin-onDielectric(SOD)EpitaxyEpitaxygrowthmethodsVapor-phaseepitaxyMetalorganicCVDMolecular-beamepitaxyQualityMeasuresCVDTroubleshooting,Gap-FillwithSpin-On-Glass(SOG),Figure11.27,ProposedHSQLow-kDielectricProcessingParameters,Table11.6,Epitaxy,EpitaxyGrowthModelEpitaxyGrowthMethodsVapor-PhaseEpitaxy(VPE)MetalorganicCVD(MOCVD)Molecular-BeamEpitaxy(MBE),SiliconEpitaxialGrowthonaSiliconWafer,