晶圓制造專題知識(shí)

Chapter4

WaferManufacturingandEpitaxyGrowing2025/1/41CrystalStructuresAmorphousNorepeatedstructureatallPolycrystallineSomerepeatedstructuresSinglecrystalOnerepeatedstructure2025/1/42AmorphousStructure2025/1/43PolycrystallineStructureGrainGrainBoundary2025/1/44SingleCrystalStructure2025/1/45WhySilicon?Abundant,cheapSilicondioxideisverystable,strongdielectric,anditiseasytogrowinthermalprocess.Largebandgap,wideoperationtemperaturerange.2025/1/46Source:2025/1/47UnitCellofSingleCrystalSilicon2025/1/48CrystalOrientations:<100>xyz<100>plane2025/1/49CrystalOrientations:<111>xyz<100>plane<111>plane2025/1/410CrystalOrientations:<110>xyz<110>plane2025/1/411<100>OrientationPlaneAtomBasiclatticecell2025/1/412<111>OrientationPlaneSiliconatomBasiclatticecell2025/1/413IllustrationofthePointDefectsSiliconAtomImpurityonsubstitutionalsiteFrenkelDefectVacancy(空位)orSchottkyDefectImpurityinInterstitialSiteSiliconInterstitial間隙2025/1/414DislocationDefects2025/1/415FromSandtoWaferQuartzsand:silicondioxideSandtometallicgradesilicon(MGS)ReactMGSpowderwithHCltoformTCSPurifyTCSbyvaporizationandcondensationReactTCStoH2toformpolysilicon(EGS)MeltEGSandpullsinglecrystalingot2025/1/416FromSandtoWafer(cont.)Cutend,polishside,andmakenotchorflatSawingotintowafersEdgerounding,lap,wetetch,andCMPLaserscribeEpitaxydeposition2025/1/417晶圓形成之步驟

FromSandtoSilicon

Heat(2023°C)SiO2

+2C

?

Si+2CO

SandCarbonMGSCarbonDioxideMGS(poly-silicon)with98%purity(1)首先由石英砂提煉成冶金級(jí)多晶矽

2025/1/418SiliconPurificationISi+HCl

TCS(vapor)

SiliconPowderHydrochlorideFiltersCondenserPurifierPureTCS(liquid)with99.9999999%Reactor,300

C2025/1/419PolysiliconDeposition,EGS

Heat(1100°C)SiHCl3+H2

?

Si+3HCl

TCS(liquid)HydrogenEGSHydrochlorideEGS(Electronic-gradeSilicon)isalsopoly-silicon2025/1/420SiliconPurificationIILiquidTCSH2CarriergasbubblesH2andTCSProcessChamberTCS+H2EGS+HClEGS2025/1/421ElectronicGradeSilicon2025/1/422CrystalPullingMakeasingle-crystalsiliconingotCzochralski(CZ)methodFloatingZone(FZ)method2025/1/423CrystalPulling:CZmethodGraphiteCrucibleSingleCrystalsiliconIngotSingleCrystalSiliconSeedQuartzCrucibleHeatingCoils1415°CMoltenSilicon2025/1/424CZCrystalPullersMitsubishMaterialsSilicon2025/1/425CZCrystalPulling2025/1/426FloatingZoneMethodHeatingCoilsPolySiRodSingleCrystalSiliconSeedCrystalHeatingCoilsMovementMoltenSilicon2025/1/427ComparisonoftheTwoMethodsCZmethodismorepopularCheaperLargerwafersize(300mminproduction)ReusablematerialsFloatingZonePuresiliconcrystal(nocrucible)Moreexpensive,smallerwafersize(150mm)Mainlyforpowerdevices.2025/1/428IngotPolishing,Flat,orNotchFlat,150mmandsmallerNotch,200mmandlarger2025/1/429WaferSawingOrientationNotchCrystalIngotSawBladeDiamondCoatingCoolantIngotMovement2025/1/430ParametersofSiliconWaferWaferSize(mm)Thickness(mm)Area(cm2)Weight(grams)27920.261.3238145.614.0510052578.659.67125625112.7217.87150675176.7227.82200725314.1652,98300775706.21127.6250.8(2in)76.2(3in)2025/1/431WaferEdgeRounding(邊緣圓滑化)WaferWafermovementWaferBeforeEdgeRoundingWaferAfterEdgeRounding2025/1/432WaferLapping(粗磨拋光)Roughpolishedconventional,abrasive,slurry-lappingToremovemajorityofsurfacedamageTocreateaflatsurface2025/1/433WetEtchRemovedefectsfromwafersurface4:1:3mixtureofHNO3(79wt%inH2O),HF(49wt%inH2O),andpureCH3COOH.Chemicalreaction:3Si+4HNO3+18HF

3H2SiF6+4NO+8H2O2025/1/434ChemicalMechanicalPolishing(CMP)SlurryPolishingPadPressureWaferHolderWafer2025/1/435200mmWaferThicknessandSurfaceRoughnessChanges76mm914mmAfterWaferSawingAfterEdgeRounding76mm914mm12.5mm814mm<2.5mm750mm725mmVirtuallyDefectFreeAfterLappingAfterEtchAfterCMP2025/1/436EpitaxyGrow(磊晶成長(zhǎng))DefinitionPurposesEpitaxyReactorsEpitaxyProcess2025/1/437Epitaxy:DefinitionGreekoriginepi:upontaxy:orderly,arrangedEpitaxiallayerisasinglecrystallayeronasinglecrystalsubstrate.2025/1/438Epitaxy:PurposeBarrierlayerforbipolartransistorReducecollectorresistancewhilekeephighbreakdownvoltage.Onlyavailablewithepitaxylayer.ImprovedeviceperformanceforCMOSandDRAMbecausemuchloweroxygen,carbonconcentrationthanthewafercrystal.2025/1/439EpitaxyApplication,BipolarTransistorn-Epipn+n+P-substrateElectronflown+BuriedLayerp+p+SiO2Al?Cu?SiBaseCollectorEmitter2025/1/440EpitaxyApplication:CMOSP-WaferN-WellP-WellSTIn+n+USGp+p+Metal1,Al?CuBPSGWP-typeEpitaxySilicon2025/1/441SingleCrystalSiliconEpitaxialLayerUseChemicalVaporDeposition(CVD)ChoosegasphaseepitaxyCanbedopedusingdopantgassource2025/1/442SiliconSourceGasesSilane

SiH4Dichlorosilane DCS SiH2Cl2Trichlorosilane TCS SiHCl3Tetrachlorosilane SiCl42025/1/443DopantSourceGasesDiborane B2H6Phosphine PH3Arsine AsH32025/1/444DCSEpitaxyGrow,ArsenicDoping

Heat(1100°C)SiH2Cl2

?

Si+2HClDCS EpiHydrochlorideAsH3?As+3/2H2

Heat(1100°C)2025/1/445SchematicofDCSEpiGrowandArsenicDopingProcessSiH2Cl2SiAsH3AsAsH3HHClH22025/1/446EpitaxialSiliconGrowthRateTrendsGrowthRate,micron/min1000/T(K)Temperature(°C)0.70.80.91.01.10.010.020.050.10.20.51.01300120011001000900800700SiH4SiH2Cl2SiHCl3SurfacereactionlimitedMasstransportlimited2025/1/447BarrelReactor

RadiationHeatingCoilsWafers2025/1/448VerticalReactorHeatingCoilsWafersReactantsReactantsandbyproducts2025/1/449HorizontalReactorHeatingCoilsWafersReactantsReactantsandbyproducts2025/1/450EpitaxyProcess,BatchSystemHydrogenpurge,temperaturerampupHClcleanEpitaxiallayergrowHydrogenpurge,temperaturecooldownNitrogenpurgeOpenChamber,waferunloading,reloading2025/1/451SingleWaferReactorHydrogenambientCapableformultiplechambersonamainframeLargewafersize(to300mm)Betteruniformitycontrol2025/1/452SingleWaferReactorHeatingLampsHeatRadiationWaferQuartzWindowReactantsReactants&byproductsQuartzLiftFingersSusceptor2025/1/453EpitaxyProcess,SingleWaferSystemHydrogenpurge,clean,temperaturerampupEpitaxiallayergrowHydrogenpurge,heatingpoweroffWaferunloading,reloadingIn-situHClclean2025/1/454WhyHydrogenPurgeMostsystemsusenitrogenaspurgegasNitrogenisaverystableabundantAt>1000

C,N2canreactwithsiliconSiNonwafersurfaceaffectsepidepositionH2isusedforepitaxychamberpurgeCleanwafersurfacebyhydridesformation2025/1/455Pro