晶圆制造专题知识市公开课一等奖百校联赛获奖课件.pptx

Chapter 4Wafer Manufacturing and Epitaxy Growing/10/101第1页Crystal StructuresAmorphousNo repeated structure at allPolycrystallineSome repeated structures Single crystalOne repeated structure/10/102第2页Amorphous Structure/10/103第3页Polycrystalline StructureGrainGrain Boundary/10/104第4页Single Crystal Structure/10/105第5页Why Silicon?Abundant,cheapSilicon dioxide is very stable,strong dielectric,and it is easy to grow in thermal process.Large band gap,wide operation temperature range./10/106第6页Source:http:/www.shef.ac.uk/chemistry/web-elements/nofr-key/Si.html/10/107第7页Unit Cell of Single Crystal Silicon/10/108第8页Crystal Orientations:xyz plane/10/109第9页Crystal Orientations:xyz plane plane/10/1010第10页Crystal Orientations:xyz plane/10/1011第11页 Orientation PlaneAtomBasic lattice cell/10/1012第12页 Orientation PlaneSilicon atomBasic lattice cell/10/1013第13页Illustration of the Point DefectsSilicon AtomImpurity on substitutional siteFrenkel DefectVacancy(空位)or Schottky DefectImpurity in Interstitial SiteSilicon Interstitial間隙/10/1014第14页Dislocation Defects/10/1015第15页From Sand to WaferQuartz sand:silicon dioxideSand to metallic grade silicon(MGS)React MGS powder with HCl to form TCSPurify TCS by vaporization and condensationReact TCS to H2 to form polysilicon(EGS)Melt EGS and pull single crystal ingot/10/1016第16页From Sand to Wafer(cont.)Cut end,polish side,and make notch or flatSaw ingot into wafersEdge rounding,lap,wet etch,and CMPLaser scribeEpitaxy deposition/10/1017第17页晶圓形成之步驟From Sand to Silicon Heat(C)SiO2 +2C Si +2CO Sand Carbon MGS Carbon DioxideMGS(poly-silicon)with 98%purity(1)首先由石英砂提煉成冶金級多晶矽/10/1018第18页Silicon Purification ISi+HCl TCS(vapor)Silicon PowderHydrochlorideFiltersCondenserPurifierPure TCS(liquid)with 99.9999999%Reactor,300 C/10/1019第19页Polysilicon Deposition,EGS Heat(1100 C)SiHCl3 +H2 Si +3HCl TCS(liquid)Hydrogen EGS HydrochlorideEGS(Electronic-grade Silicon)is also poly-silicon/10/1020第20页Silicon Purification IILiquid TCSH2Carrier gas bubblesH2 and TCSProcess ChamberTCS+H2EGS+HClEGS/10/1021第21页Electronic Grade SiliconSource:http:/ PullingMake a single-crystal silicon ingotCzochralski(CZ)methodFloating Zone(FZ)method/10/1023第23页 Crystal Pulling:CZ methodGraphite CrucibleSingle Crystal silicon IngotSingle Crystal Silicon SeedQuartz CrucibleHeating Coils1415 CMolten Silicon/10/1024第24页CZ Crystal PullersMitsubish Materials SiliconSource:http:/ Crystal PullingSource:http:/ Zone MethodHeating CoilsPoly Si RodSingle Crystal SiliconSeed CrystalHeating Coils MovementMolten Silicon/10/1027第27页Comparison of the Two MethodsCZ method is more popularCheaperLarger wafer size(300 mm in production)Reusable materialsFloating ZonePure silicon crystal(no crucible)More expensive,smaller wafer size(150 mm)Mainly for power devices./10/1028第28页Ingot Polishing,Flat,or NotchFlat,150 mm and smallerNotch,200 mm and larger/10/1029第29页Wafer SawingOrientation NotchCrystal IngotSaw BladeDiamond CoatingCoolantIngot Movement/10/1030第30页Parameters of Silicon WaferWafer Size (mm)Thickness(mm)Area(cm2)Weight(grams)27920.261.3238145.614.0510052578.659.67125625112.7217.87150675176.7227.82200725314.1652,98300775706.21127.6250.8(2 in)76.2(3in)/10/1031第31页Wafer Edge Rounding(邊緣圓滑化)WaferWafer movementWafer Before Edge RoundingWafer After Edge Rounding/10/1032第32页Wafer Lapping(粗磨拋光)Rough polished conventional,abrasive,slurry-lappingTo remove majority of surface damage To create a flat surface/10/1033第33页Wet EtchRemove defects from wafer surface4:1:3 mixture of HNO3(79 wt%in H2O),HF(49 wt%in H2O),and pure CH3COOH.Chemical reaction:3 Si+4 HNO3+18 HF 3 H2SiF6+4 NO+8 H2O/10/1034第34页Chemical Mechanical Polishing(CMP)SlurryPolishing PadPressureWafer HolderWafer/10/1035第35页200 mm Wafer Thickness and Surface Roughness Changes76 mm914 mmAfter Wafer SawingAfter Edge Rounding76 mm914 mm12.5 mm814 mm 1000 C,N2 can react with silicon SiN on wafer surface affects epi depositionH2 is used for epitaxy chamber purgeClean wafer surface by hydrides formation/10/1055第55页Properties of Hydrogen/10/1056第56页Defects in Epitaxy LayerDislocationStacking Fault from Surface NucleationImpurity ParticleHillockStacking Fault form Substrate Stacking Fault After S.M.Zses VLSI TechnologySubstrateEpi Layer/10/1057第57页Future TrendsLarger wafer sizeSingle wafer epitaxial growLow temperature epitaxyUltra high vacuum(UHV,to 10-9 Torr)Selective epitaxy/10/1058第58页SummarySilicon is abundant,cheap and has strong,stable and easy grown oxide.and CZ and floating zone,CZ is more popularSawing,edging,lapping,etching and CMP/10/1059第59页SummaryEpitaxy:single crystal on single crystalNeeded for bipolar and high performance CMOS,DRAM.Silane,DCS,TCS as silicon precursorsB2H6 as P-type dopantPH3 and AsH3 as N-type dopantsBatch and single wafer systems/10/1060第60页