功能材料4：半導(dǎo)體材料制造

第三章：晶體材料與半導(dǎo)體加工技術(shù)

CrystalMaterialsandSemiconductor

ProcessingTechnology3.1單晶材料的基本物性3.2晶體缺陷3.3半導(dǎo)體晶體制備3.4半導(dǎo)體芯片加工技術(shù)

§3.1單晶材料的基本物性

BasicPropertiesofCrystalMaterials3.1.1晶體的宏觀通性GerneralMacro-properties

晶面角守恒性Constancyofinterfacialangles均勻性homogeneity各向異性anisotropy解理性cleavage對(duì)稱性

symmetry3.1.2晶體物理性質(zhì)與微觀對(duì)稱性的關(guān)系

Relationshipbetweenthephysicproperties

andmicro-symmetryofcrystals

晶體壓電性：不具有中心對(duì)稱的點(diǎn)群（20個(gè)）晶體熱釋電：有唯一極軸、存在自發(fā)極化，受熱后正負(fù)離子相對(duì)移動(dòng)晶體鐵電性：在外電場(chǎng)作用下，可以自發(fā)極化3.2晶體的缺陷Defectsofcrystals

3.2.1微觀缺陷3.2.2

宏觀缺陷

【微觀缺陷】偏離理想晶體0維:點(diǎn)缺陷1維:線缺陷2維:面缺陷3維缺陷原子缺陷電子缺陷:能級(jí)躍遷本征缺陷:熱缺陷非本征缺陷:雜質(zhì)缺陷(固溶體)非化學(xué)計(jì)量缺陷韌形位錯(cuò)固溶體多晶(陶瓷)非晶態(tài)表面界面晶界表面↑↑↑納米粉體納米結(jié)構(gòu)螺旋位錯(cuò)晶?！揪€缺陷】linedislocations

韌形位錯(cuò)edgedislocation

螺旋位錯(cuò)screwdislocation特點(diǎn)：

1.非平衡缺陷

2.位錯(cuò)單位均為一個(gè)格矢，即b

(BurgersVector)韌形位錯(cuò)edgedislocationEdgedislocation(linedefect)位錯(cuò)的移動(dòng)：滑移螺旋位錯(cuò)screwdislocation單晶硅中觀察到的螺旋位錯(cuò)缺陷表面（對(duì)真空）surface界面interface

【面缺陷】Planardislocations面缺陷（固體）普通晶粒間界小角度晶界孿晶界相界固－氣界面固－液界面固－固界面

（晶界）

孿晶界小角度晶界高分辨率點(diǎn)電鏡：螺旋位錯(cuò)和小角度晶界1HRTEMofScrewDislocationsinaSmallAngleGrainBoundaryDislocationsformattheinterfacebetweenthefirstlayerofgalliumnitridetobedepositedandthesapphiresubstrate.Thedislocationscanthreadtheirwayintotheactivelayerofthedevice,butdonotseemtodegradethedeviceproperties.【宏觀缺陷】Macrocopicdefects:

開裂splitting,

包裹體inclusion生長(zhǎng)層growthlayer

生長(zhǎng)條紋growthstriation胞狀組織cellularstructrue

楔化wedging包裹體開裂生長(zhǎng)條紋

生長(zhǎng)層生長(zhǎng)層生長(zhǎng)條紋

Siliconsinglecrystalsweregrownbythefloating-zonemethodusinganinfraredimagefurnaceinthewiderangeofoxygenpartialpressuredefinedattheinletofthefurnace§3.3半導(dǎo)體晶體及晶片制備技術(shù)

ProcessingTechnologyofSemiconductor

Crystal&itsWaferFromsandtowafer3.3.1概述

IntroductionTheoutercrustofthisplanetconsistsofallkindsofsilicates(Si+O+somethingelse).Si,infact,accountsforabout26%ofthecrust,whileOabout49%.LiquidSiindeeddoesreactwithallsubstancesknowntoman-itisanuniversalsolvent.ThismakescrystalgrowthfromliquidSisomewhattricky,becausehowdoyoucontainyourliquidSi?Fortunately,somematerials-especiallySiO2-dissolveonlyveryslowly.But(!!!)therewillalwaysbesomedissolvedSiO2andthereforeoxygeninyourliquidSi,andthatmakesithardtoproduceSicrystalswithverylowoxygenconcentrations.3.3.2

硅原料處理和提純

Producing"Raw"Siliconanditspurifying

SiO2

+

2C=Si+2CO2000oC

【生硅的制備】【硅提純】Purifyingofsi

WhatwedohavetodoistopurifytheMG-Si-about109fold!

（a）First,SiisconvertedtoSiHCl3ina"fluidbed"

Si

+

3HCl

=SiHCl3

+

H2（b）Second,theSiHCl3isdistilled(likewodka),resultinginextremelypureTrichlorosilane（三氯硅烷）（c）Third,high-puritySiisproducedbya"ChemicalVaporDeposition"(CVD)processCVDSchematicdiagram以SiHC3(8N)為原料，通過CVD，得到超純的多晶硅。（hyperpure

poly-Si）

1000oC

SiHCl3

+

H2＝

Si

+

3HClMoreinformationThechemistryisextremelydangerous:AsH3andPH3areamongthemostpoisonoussubstancesknowntomankind;PH3wasactuallyusedasatoxicgasinworldwarIIwithdisastrouseffects.H2andSiHCl3areeasilycombustibleifnotoutrightexplosive,andHCl(ingaseousform)isevenmoredangerousthantheliquidacidandextremelycorrosive.Handlingthesechemicals,includingthesafeandenvironmentallysounddisposal,isneithereasynorcheap.·Still,itworksandabut10.000tonsofpoly-Siareproducedatpresent(2000)withthistechnology,whichwaspioneeredbySiemensAGinthesixties.Itisnotcheap,however,andhasnopotentialtoobecomeverycheapeither.Thelinkprovidestodaysspecificationsfortheproduct,andhereisanexample:·Whilethisisnotextremelyimportantforthemicroelectronicsindustry(wheretheaddedvalueofthechipbyfarsurpassesthecostsoftheSi),itpreventsotherSiproducts,especiallycheapsolarcells(inconnectionwithalltheotherexpensiveprocessesbeforeandafterthepoly-Siprocess).Startingwiththefirstoilcrisisin1976,manyprojectsintheUSAandEuropetriedtocomeupwithacheapersourceofhighpuritypoly-Si,sofarwithoutmuchsuccess3.3.3單晶制備

SingleCrystalGrowth

【CZ法】Czochrolskiprocess

又稱：直拉法或喬赫拉斯法

·Essentially,acrystalis"pulled"outofavesselcontainingliquidSibydippingaseedcrystalintotheliquidatasurfacetemperatureofthemeltjustabovethemeltingpoint.·Everythingelsedeterminesthequalityandhomogeneity-crystalgrowingisstillasmuchanartasascience!Hereweonlylookatonemajorpoint,the

segregationcoefficient

ksegofimpurityatoms·"Equilibrium"referstoagrowthspeedof0mm/minor,morepractically,verylowgrowthrates.·Onthepositiveside,thecrystalwillbecleanerthantheliquid,crystalgrowingissimultaneouslyapurificationmethod.·Thenegativeside:Thedistributionofimpurities-andthatincludesthedopingelementsandoxygen-willchangealongthelengthofacrystal-ahomogeneousdopingetc.isdifficulttoachieve.ThisisWhypracticallyonlyAs,P,andBareusedfordoping?Theirsegregationcoefficientiscloseto1.(ButBidifficultorimpossible).Moreinformation【區(qū)熔法

】FloatZoneCrystalGrowth

原理：Themethodwasfirstusedforpurificationtakingadvantageofthesmallsegregationcoefficientsofmanyimpurities.Theimpuritiescontainedinthefeedmaterialwouldthenprefertoremaininthemeltandthuscouldbeswepttotheendofthefeedstock.

特點(diǎn)：Sincethemeltnevercomesintocontactwithanythingbutvacuum(orinertgases),thereisnoincorporationofimpuritiesthatthemeltpicksupbydissolvingthecruciblematerialasintheCZcrystalgrowthmethod.Thisisespeciallytrueforoxygen,whichcannotbeavoidedinCZcrystalgrowth.FZcrystalsthereforearealwaysusedwhenverylowoxygenconcentrationsareimportant.區(qū)熔法原理圖區(qū)熔法提純?cè)韴D3.3.4晶片技術(shù)WaferTechnology

晶片拋光(lapping)3.4半導(dǎo)體芯片加工技術(shù)

TechnologiesforProcessingSemiconductor

(FromWafertoChip)平板印刷技術(shù)Si氧化技術(shù)濺射技術(shù)CVD技術(shù)外延技術(shù)分子束外延技術(shù)離子注入技術(shù)等離子腐蝕技術(shù)化學(xué)腐蝕技術(shù)蒸發(fā)技術(shù)旋式涂布技術(shù)半導(dǎo)體芯片相關(guān)制造技術(shù)CMOSProcessSequence

CosmeticCAPSDepositionSi(P)TINN-WellSiO2N+P+D1A1D2CAPSA2CMOSProcessSequence

CosmeticFirstOxideSi(P)SiO2CMOSProcessSequence

CosmeticN-WellSi(P)SiO2SurfacepictureCMOSProcessSequence

CosmeticDrivingWellSi(P)SiO2SurfacepictureN-WellCMOSProcessSequence

N-WellCosmeticDepositNitrideSi(P)SiO2Si3N4SurfacepictureCMOSProcessSequence

CosmeticSDGetchSi(P)N-WellSiO2Si3N4SurfacepictureCMOSProcessSequence

CosmeticFieldOxidationN-WellSiO2Si(P)Si3N4SurfacepictureCMOSProcessSequence

CosmeticSi3N4StrippingN-WellSiO2Si(P)SurfacepictureCMOSProcessSequence

N-WellCosmeticPolysiliconDepositionSiO2Si(P)SurfacepicturePolyCMOSProcessSequence

CosmeticN-WellSi(P)SurfacepicturePolyetchSiO2PolyCMOSProcessSequence

CosmeticLPTEOSDepositionN-WellSi(P)SiO2SurfacepictureLPTEOSCMOSProcessSequence

CosmeticSpaceretchN-WellSi(P)SiO2PolySpacerSurfacepictureCMOSProcessSequence

CosmeticN-SDN-WellSi(P)SiO2PolySurfacepictureCMOSProcessSequence

CosmeticSi(P)P-SDN-WellSiO2PolySurfacepictureCMOSProcessSequence

CosmeticDepositD1N-WellSi(P)SiO2SurfacepictureN+P+D1CMOSProcessSequence

CosmeticW1etchN-WellSi(P)SiO2SurfacepictureN+P+D1W1CMOSProcessSequence

CosmeticTINN-WellSi(P)SiO2SurfacepictureN+P+D1TINCMOSProcessSequence

CosmeticSputterALN-WellSi(P)SiO2SurfacepictureN+P+D1TINALCMOSProcessSequence

CosmeticALetchN-WellSi(P)SiO2SurfacepictureN+P+D1TINALCMOSProcessSequence

CosmeticDepositD2N-WellSi(P)SiO2SurfacepictureN+P+D1TINALD2CMOSProcessSequence

CosmeticVIAetchSi(P)SurfacepictureTINN-WellSiO2N+P+D1ALVIAD2CMOSProcessSequence

CosmeticA2etchSi(P)SurfacepictureTINN-WellSiO2N+P+D1ALA2D2CMOSProcessSequence

CosmeticCAPSDepositionSi(P)TINN-WellSiO2N+P+D1A1D2CAPSA2CMOSProcessSequence

CAPSPETEOSTEOSSurfacepictureCosmeticPADetch

A2A1SiO2SEMpicture

----VIA平板印刷技術(shù)Si氧化技術(shù)濺射技術(shù)CVD技術(shù)外延技術(shù)分子束外延技術(shù)離子注入技術(shù)等離子腐蝕技術(shù)化學(xué)腐蝕技術(shù)蒸發(fā)技術(shù)旋式涂布技術(shù)半導(dǎo)體芯片相關(guān)制造技術(shù)【平板印刷技術(shù)】LithographyTechniques掩模層光阻層曝光抗蝕膜顯影圖案轉(zhuǎn)移去除光阻層去除掩模層圖案層完成圖案電磁波光頻部分：紫外、可見、紅外5~0.2eV能量eV極遠(yuǎn)紫外光刻技術(shù)

EUVlithographyTechniquesThermaloxidation.Thismeansthatasolidstatereaction(Si+O2=SiO2)isused:JustexposeSitoO2atsufficientlyhightemperaturesandanoxidewillgrowtoathicknessdeterminedbythetemperatureandtheoxidationtime.【Si氧化技術(shù)】【外延技術(shù)】Epitaxy

Aprecisecontinuationofthesubstratelattice.Thereshouldbenowaytoidentifytheinterfaceaftertheepitaxiallayerhasbeendeposited.Thismeansthat

nolatticedefectsshouldbegenerated.單晶襯底+單晶膜

———外延生長(zhǎng)

Points:Dopingoftheepitaxiallayerwithhighprecision(e.g.5Wcm±5%),andthedopingisusuallyverydifferentfromthatofthesubstrate.Thepictureontherightsymbolizesthatbythetwodifferentlycoloreddopingatoms.Precisethicknesscontrol,e.g.d=1,2μm±10%overtheentirewafer,fromwafertowaferandfromdaytoday.Nowthereisachallenge:Ifyoumetthefirstpointandthuscan'ttellwheretheinterfaceis-howdoyoumeasurethethickness?(Theanswer:Onlyelectronically,e.g.byfindingthepositionofthepn-junctionproduced).Cleanliness:Nocontaminantsdiffusingintothesubstrateandtheepitaxiallayerareallowed.【分子束外延技術(shù)】MBE

(MolecularBeamEpitaxy).背景：超晶格材料要求，是CVD外延技術(shù)的延伸。特點(diǎn)：每層10nm精度1個(gè)原子層MBE:1μm/h(CVD1-10μm/min).

Everyatomreachingthesurfaceoftheheatedsubstratehasenoughtimetomigratearoundandfindhisplacetobuildupanewcrystallattice.超晶格

superlattice

Inthelate1960s,EsakiandTsusuggestedthatitshouldbepossibletogrowalternatinglayersofGaAsandAluminum-Gallium-Arsenide(AlGaAs)inaperiodicarraytoformasuperlatticestructurewhichwouldhaveremarkablydifferentelectronicpropertiesfromthoseofbulkGaAsorAlGaAs.Thesewouldbeman-madecrystalswithasuper-periodicity,overandaboveatomicperiodicityofcrystallinematerials,correspondingtothelayerthicknessofd=dGaAs+dAlGaAs,withabinarymodulationofthematerialcompositionalongthecrystalgrowthdirection.超晶格

superlattice

【濺射技術(shù)】SputteringorSputterDeposition

(物理氣相沉積-1)

屬物理氣相沉積主要用于金屬層的沉積Thetargetatomshitthesubstratewithanenergylargeenoughsothey"getstuck",butnotsolargeastoliberatesubstrateatoms.Sputteredlayersthereforeusuallystickwelltothesubstrate(incontrasttoothertechniques,mostnotablyevaporation).Allatomsofthetargetwillbecomedeposited,inprettymuchthesamecompositionasinthetarget.Itisthuspossible,e.g.,todepositasilicideslightlyoffthestoichiometriccomposition(advantageousforallkindsofreason).Inotherwords,ifyouneedtodeposite.g.TaSi2-xwithx?0,01-0,1,sputteringisthewaytodoitbecauseitiscomparativelyeasytochangethetargetcomposition.Thetargetatomshitthesubstratecomingfromalldirections.Inagoodapproximation,thefluxofatomsleavingthetargetatanangleFrelativetothenormalonthetargetisproportionaltocosF.Thishasprofoundimplicationsforthecoverageoftopographicstructures.Homogeneouscoverageofthesubstrateisrelativelyeasytoachieve-justmakethesubstrateholderandthetargetbigenough.Theprocessisalsorelativelyeasilyscaledtolargersizesubstrates-simplymakeeverythingbigger.Moreinformation【離子注入技術(shù)】IonImplantation

(物理氣相沉積-2)

Whatisionimplantation?

Ionsofsomematerial-almostalwaysthedopants

As,B,P-areimplanted,i.e.shotintothesubstrate.原理圖離子注入技術(shù)在高技術(shù)陶瓷用于表面改性Howisitdone?Obviouslyyouneedanionbeam,characterizedbythreebasicparameters:Thekindoftheions.Almosteverythingfromtheperiodictablecouldbeimplanted,butinpracticeyouwillfindthatonlySb(asdopant)andoccasionallyGeandOarebeingusedbesidesthecommondopants

As,B,andP.TheenergyoftheionsineV.Thisisdirectlygivenbytheacceleratingvoltageemployedandissomewhereintherangeof(2-200)kV,alwaysallowingforextremesinbothdirectionsforspecialapplications.TheenergyoftheiontogetherwithitsmassdeterminehowfaritwillbeshotintoaSisubstrate.ThefollowinggraphgivesanideaofthedistributionofBatomsafterimplantationwithvariousenergies.ThecurvesforAsorP