Michael quirk_半導體制造技術-第11章_淀積.ppt

SemiconductorManufacturingTechnologyMichaelQuirk JulianSerda October2001byPrenticeHallChapter11Deposition 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 250 450 C 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