微電子工藝17zhang課件

第17章離子注入1摻雜原因：本征硅導(dǎo)電能力很差。在硅中加入少量雜質(zhì)，結(jié)構(gòu)和電導(dǎo)率變化。2本章目標(biāo)1. 解釋摻雜在硅片制造過程中的目的和應(yīng)用.2. 討論雜質(zhì)擴(kuò)散的原理和過程.3. 對(duì)離子注入有整體的認(rèn)識(shí)，包括優(yōu)缺點(diǎn).4. 討論劑量和射程在離子注入中的重要性.5. 列舉離子注入機(jī)的５個(gè)主要子系統(tǒng).6. 解釋離子注入中的退火效應(yīng)和溝道效應(yīng).7. 描述離子注入的各種應(yīng)用.

3具有摻雜區(qū)的CMOS結(jié)構(gòu)n-channelTransistorp-channelTransistorLIoxidep–epitaxiallayerp+siliconsubstrateSTISTISTIn+p+p-welln-wellp+p–p+p–p+n+n–n+n–n+ABCEFDGHKLIJMNOn+nn++p+pp++Figure17.1

5CMOS制作中的一般摻雜工藝6離子注入在硅片流程中UsedwithpermissionfromLanceKinney,AMDImplantDiffusionTest/SortEtchPolishPhotoCompletedwaferUnpatternedwaferWaferstartThinFilmsWaferfabrication(front-end)Hardmask(oxideornitride)AnnealafterimplantPhotoresistmaskFigure17.2

717.2擴(kuò)散1.擴(kuò)散原理三步預(yù)擴(kuò)散推進(jìn)激活雜質(zhì)移動(dòng)固溶度橫向擴(kuò)散2.擴(kuò)散工藝硅片清洗雜質(zhì)源

9硅中的雜質(zhì)擴(kuò)散DisplacedsiliconatomininterstitialsiteSiSiSiSiSiSiSiSiSic)MechanicalinterstitialdisplacementSiSiSiSiSiSiSiSiSia)Siliconlatticestructureb)SubstitutionaldiffusionSiSiSiSiSiSiSiSiVacancyDopantd)InterstitialdiffusionSiSiSiSiSiSiSiSiSiDopantininterstitialsiteFigure17.4

10擴(kuò)散原理

一.

擴(kuò)散流方程1/17/2023擴(kuò)散系數(shù)與溫度有關(guān)D0：擴(kuò)散率，E：擴(kuò)散工藝激活能，k0：玻耳茲曼常數(shù)，T：絕對(duì)溫度。3－613硅中的固溶度極限1100°CTable17.3

14擴(kuò)散工藝擴(kuò)散8個(gè)步驟:1. 進(jìn)行質(zhì)量測試以保證工具滿足生產(chǎn)質(zhì)量指標(biāo).2. 使用批控制系統(tǒng)，驗(yàn)證硅片特性.3. 下載包含所需工藝參數(shù)的工藝菜單.4. 開啟擴(kuò)散爐，包括溫度分布.5. 清洗硅片并浸泡HF，去除自然氧化層.6. 預(yù)淀積：把硅片裝入擴(kuò)散爐，擴(kuò)散雜質(zhì).7. 推進(jìn)：升高爐溫，推進(jìn)并激活雜質(zhì)，然后撤出硅片.8. 測量、評(píng)價(jià)、記錄結(jié)深和電阻.

1517.3離子注入1.概況控制摻雜濃度（數(shù)量、深度）離子注入的優(yōu)點(diǎn)離子注入的缺點(diǎn)2.離子注入?yún)?shù)劑量射程

17控制摻雜濃度、深度a) 低摻雜濃度(n–,p–)淺結(jié)(xj)MaskMaskSiliconsubstratexjLowenergyLowdoseFastscanspeedBeamscanDopantionsIonimplanterb) 高摻雜濃度(n+,p+)和深結(jié)(xj)BeamscanHighenergyHighdoseSlowscanspeedMaskMaskSiliconsubstratexjIonimplanterFigure17.5

18離子注入機(jī)示意圖IonsourceAnalyzingmagnetAccelerationcolumnIonbeamPlasmaProcesschamberExtractionassemblyScanningdisk19離子注入的優(yōu)點(diǎn)1. 精確控制摻雜濃度2. 很好的雜質(zhì)均勻性3. 對(duì)雜質(zhì)深度很好控制4. 產(chǎn)生單一離子束5. 低溫工藝6. 注入的離子能穿過薄膜7. 無固溶度極限Table17.5

21缺點(diǎn)1.輻射損傷。高溫退火修復(fù)。2.設(shè)備復(fù)雜（比擴(kuò)散）注入劑量22射程能量電子阻止Se、核阻止Sn23雜質(zhì)離子的射程和投影射程IncidentionbeamSiliconsubstrateStoppingpointforasingleionRpDRpdopantdistributionFigure17.7

25投影射程圖ImplantationEnergy(keV)ProjectedRange,Rp(mm)101001,0000.010.11.0BPAsSbImplantingintoSiliconFigure17.8

RedrawnfromB.El-Kareh,FundamentalsofSemiconductorProcessingTechnologies,(Boston:Kluwer,1995),p.38826注入雜質(zhì)能量損失SiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiSiX-raysElectroniccollisionAtomiccollisionDisplacedSiatomEnergeticdopantionSiliconcrystallatticeFigure17.9

2717.4離子注入機(jī)離子源引出電極（吸極）和離子分析器加速管掃描系統(tǒng)工藝室退火溝道效應(yīng)顆粒

29離子源和吸極裝配圖UsedwithpermissionfromAppliedMaterialsTechnology,PrecisionImplanter9500

Figure17.11

ExtractionassemblySourcechamberTurbopumpIonsourceinsulatorBernasionsourceassemblyArcchamberExtractionelectrodeExtractionassemblyIonbeam30Bernas離子源裝配圖前板狹縫起弧室燈絲電子反射器氣體入口5V電子反射器Anode+100V起弧室氣化噴嘴電爐氣體導(dǎo)入管DI冷卻水入口摻雜劑氣體入口UsedwithpermissionfromAppliedMaterialsTechnology,PrecisionImplanter9500Figure17.12

31離子源和吸極交互作用裝配圖UsedwithpermissionfromAppliedMaterialsTechnology,PrecisionImplanter9500

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----------NSNS120VArc吸出組件IonSource60kVExtraction2.5kVSuppressionSourcemagnetsupply5VFilamentToPA+IonbeamTerminalreference(PAvoltage)SuppressionelectrodeGroundedelectrodeArcchamberFigure17.13

32分析磁體石墨I(xiàn)onsourceAnalyzingmagnetIonbeamExtractionassemblyLighterionsHeavyionsNeutralsFigure17.14

339.2.1硅片制造廠的分區(qū)概述—離子注入34離子注入機(jī)分析磁體35加速管100MW100MW100MW100MW100MW0kV+100kV+80kV+20kV+40kV+60kV+100kVIonbeamIonbeamToprocesschamberElectrodeFromanalyzingmagnetFigure17.15

36劑量與能量圖鄰近吸收PresentapplicationsEvolvingapplicationsPolydopingSource/drainDamageengineeringBuriedlayersRetrogradewellsTriplewellsVtadjustChannelanddrainengineering0.1110100100010,0001017101110121013101410151016Energy(keV)Dose(atoms/cm2)UsedwithpermissionfromVarianSemiconductorEquipment37高能注入機(jī)的線性加速器SourceAtomicmassanalysismagnetLinearacceleratorFinalenergyanalysismagnetScandiskWaferFigure17.17

38空間電荷中和+++++++++++++++++++++++++Crosssectionofbeamwithspacechargeneutralization+++++++++++++++++++++++++Crosssectionofbeamblow-upDopantionSecondaryelectronFigure17.18

39中性束流陷阱SourceAnalyzingMagnetAcceleratorNeutralbeamtrapFocussinganodeY-axisdeflectionX-axisdeflectionNeutralbeampathWaferIonbeamGroundedcollectorplateUsedwithpermissionfromVarianSemiconductorEquipmentFigure17.19

40硅片的靜電離子束掃描+IonbeamY-axisdeflectionX-axisdeflectionWaferTwistTiltHighfrequencyX-axisdeflectionLowfrequencyY-axisdeflectionFigure17.20

41注入陰影效應(yīng)Resista)MechanicalscanningwithnotiltIonbeamb)ElectrostaticscanningwithnormaltiltResistIonbeamFigure17.21

42離子注入硅片的機(jī)械掃描OuterscanradiusInnerscanradiusImplantarea(calculated)SpillovercupRotationIonbeamUsedwithpermissionfromVarianSemiconductorEquipment,VIISion80IonImplanterFigure17.22

43控制硅片充電的電子噴淋AdaptedfromEatonNV10ionimplanter,circa1983++++++++++++++++++++++++++++++++++++++++++Ionbeam-BiasedapertureElectrongunSecondaryelectrontargetSecondaryelectrons+Ion-electronrecombinationWaferFigure17.23

44控制硅片充電的等離子體噴淋-BiasedapertureIonbeamNeutralizedatomsWaferscandirectionCurrent(dose)monitorPlasmaelectronfloodchamberArgongasinletElectronemissionChamberwall+++++++++++++++++++++++++SNSN++++++++ArArArFigure17.24

45離子注入機(jī)的終端臺(tái)PhotographprovidedcourtesyofInternationalSEMATECHPhoto17.3

46注入工藝腔的硅片傳送器UsedwithpermissionfromVarianSemiconductorEquipment,VIISion200IonImplanterVIISion終端臺(tái)ProcessChamberTerminalSubsystemSourceSubsystem注入子系統(tǒng)Operatorinterface片架真空鎖硅片傳送器ScandiskVideomonitorWallFigure17.25

47法拉第杯電流測量RedraawnfromS.Ghandhi,VLSIFabricatonPrinciples:SiliconandGalliumArsenide,2ded.,(NewYork:Wiley,1994),p.417ScanningdiskwithwafersScanningdirectionFaradaycupSuppressorapertureCurrentintegratorSamplingslitindiskIonbeamFigure17.26

48硅單晶的退火RepairedSilatticestructureandactivateddopant-siliconbondsb)Silatticeafterannealinga)DamagedSilatticeduringimplantIonBeamFigure17.27

49退火1.不退火的害處：擴(kuò)散或注入的雜質(zhì)沒有被激活，不能成為施主或受主。2.退火的好處：激活雜質(zhì)，修復(fù)晶格缺陷。（注入造成的）原理：500°C修復(fù)晶格，950°C激活1.高溫爐退火，800-1000度退火30分鐘，導(dǎo)致雜質(zhì)的再擴(kuò)散。2.快速熱處理RTA：1000°下短暫時(shí)間？瞬時(shí)增強(qiáng)擴(kuò)散：嚴(yán)格控制50沿<110>軸的硅晶格視圖UsedwithpermissionfromEdgardTorresDesignsFigure17.28

51離子入射角與溝道UsedwithpermissionfromEdgardTorresDesigns<111><100><110>Figure17.29

52來自顆粒沾污的注入損傷MaskMaskSiliconSubstrateBeamscanIonimplanterParticlecreatesavoidinimplantedareaFigure17.30

5317.5離子注入的發(fā)展趨勢不同的離子注入工藝深埋層倒摻雜阱穿通阻擋層閾值電壓調(diào)整輕摻雜漏極(LDD)源/漏注入多晶硅柵溝槽電容超淺結(jié)絕緣體上硅(SOI)

541深埋層Figure17.31

n-wellp-wellp-Epilayerp+Siliconsubstratep+Buriedlayer倒摻雜阱552倒摻雜阱RetrogradeWelln-wellp-wellp+Buriedlayerp+Siliconsubstraten-typedopantp-typedopantp++n++Figure17.32

563穿通阻擋層n-wellp-wellp+Buriedlayerp+Siliconsubstraten-typedopantp-typedopantp+p++n+n++Figure17.33

574.閾值電壓調(diào)整n-wellp-wellp+Buriedlayerp+Siliconsubstraten-typedopantp-typedopantp+p++pn+n++nFigure17.34

585.LDD6.源漏注入++++++++----------++++++++++++++++----------------n-wellp-wellp+Buriedlayerp+Siliconsubstratep+S/Dimplantn+S/DimplantSpaceroxideDrainSourceDrainSourceb) p+andn+Source/drainimplants (performedin