Lithography-Training-Materials

LithographySystemPhotolithographySystem&ProcessChienMingWangLithographySystemOutline•Introduction•ExposureSystem•CoatingandDevelopmentSystem•Metrologysystem•SummaryLithographySystemICfabricationProcessLithographySystemSolventH+H+Diffusion&reactionDissolutionPrebakeAerialimagePEBDevelopment(Softbake)(postexposurebake)Lithography:Transferthepatternsonmasktowafertoactmaskduringetchorimplantprocess1.CoatingPhotoresist2.Stepperexposure3.DevelopmentLithographySystemOutlineoftheLithographyProcessSubstratePretreatmentSpinCoatSoftBake(Pre-bake)ExposePostExposureBake(PEB)DevelopADICDmeasurementOverlayEtchLithographySystemLithographyProcess•ProcessFlowwaferHMDSExposureresistDevelopingInspection相紙前處理上銀膠(相紙)曝光顯影檢查(表面處理)(上感光物質)(曝光系統)(顯影化學劑)底片光罩ETCHLithographySystemSystemsinPHOTOFabcontactMetalTrack:resistcoating,baking,development.Stepper:exposure.(深紫外光步進曝光機)CD-SEM:CD(criticaldimension)measurement.(掃瞄式電子顯微鏡).OMorOST(opticalstation):Inspection.Overlay:overlaymeasurement.(疊對量測儀)DefectInspection(KLA2138)LithographySystemTwoCriterions:CDv.s.Overlay0.30um0.30um0.25um0.30um0.30um0.30um0.25um0.25um0.25um0.25um0.18um0.18um0.20um0.20um0.18um0.20um0.20um0.50um0.70um0.70um0.50um0.20um0.50umLithographySystemWhatarerequiredforLithography•Fordesignrule:L/S=180/200nm(Pitch=0.38um)–Resolution–ExposureLatitude–DepthofFocus(DOF)–ProximityBias–Linearity–Line-edgeRoughness–LineEndshortening–AspectRatio–Resistfilmloss–CDuniformity–EtchSelectivityPRSiONPolyLSPitch=L+SLithographySystemResolutionexampleLithographySystemDepthofFocus(DOF)•Ingeneral,DOFcanbethoughtoftherangeoffocuserrorsthataprocesscantolerateandstillgiveacceptancelithographicresults.•AsampledefinitionofDOF:therangeoffocusthatkeepthelinewidth,sidewallangleandresistlosswithintheirstatedspecifications.20253035-0.6-0.4-0.20.00.2Dose(mJ/cm2)FocusOverlapProcessWindowdm-L15im-L15OverlapF-0.26E29.53PWSet1Doc:ProDATA1LithographySystemDOFLithographySystemOpticalProximityEffect(OPE)Line-endShorteningPitchEffectCornerRoundingCDapproachesexposurewave-length,patternsonthemasknolongerprintedfaithfullyLithographySystemProximityEffect012345678910130140150160170180190200210220beforeOPCafterOPCCD(nm)DutyratioLithographySystem1999ITRSRoadmapLithographySystemRoadmapAccelerationYear95969798990001020304050607NTRS’94NTRS’97ITRS’98Technologynode350250180150130100Metalhalfpitch350250180150130100Via360260180140•Dimensionsareinnm.LithographySystemCopyright©1998NumericalTechnologies,Inc.LithographySystemTheProblemofImagingThetypeofphotoresistpatternthatonewantstoproduceisthesmallestonewith:•Clearlydefinededges.•Verticalprofiles(usually).•Smalldeviationinwidthfromtarget.LithographySystemStepperApproach–Reducingtheexposingwavelengthofthelightsource,l–Increasingthenumericalapertureoftheobjectivelens,NAProcessApproach–Reducingtheempiricaldeterminedprocesscoefficient,K1–Increasingtheempiricaldeterminedprocesscoefficient,K2Howtopushthelimitsofopticallithography?ResolutionDepthofFocusR=k1lDOF=k2l2l2Rk1k2=DOFR=k1k2DOFlLithographySystemExposureToolfor130nmand100nmTechnologyNodeLithographySystemKeyTechnologiesofMicrolithographyOff-AxisIllumination(OAI)AdvancedResistProcessAnti-ReflectionCoatingThinFilmImagingPhaseShiftMaskOpticalProximityCorrectionLightSource:KrF248nmArF193nm•l,resolution•OAI-obliqueillumination-0th/1stordercollected-enhancedensefeatures-combinedw/SBOPCtoimproveisolatedfeatures•PSM-180ophaseinterference-HTPSMandLevensonPSM•OPC-CD+processwindow•Resist-dependonpatternandilluminationcondition•Reflection-importantforgoodCDcontrolPupilFilteringFLEXLithographySystemOutline•Introduction•ExposureSystem•CoatingandDevelopmentSystem•Metrologysystem•SummaryLithographySystemOpticalImageSystemFeatures•ResolutionImproves1.IncreaseNA2.Shortenwavelength3.Decreasek1-factor4.Toreduceaberrations•DOF:DependingontheNA,Wavelength,k1,k2LithographySystemCurrentstatusofExposureToolPAS5500/100DPAS5500/250CPAS5500/300CPAS5500/400BPAS5500/550DPAS5500/700DPAS5500/950Bl365nm365nm248nm365nm248nm248nm193nmStepperorScannerStep&RepeatStep&RepeatStep&RepeatStep&ScanStep&ScanStep&ScanStep&ScanNAVariable0.48to0.60Variable0.48to0.60Variable0.4to0.57Variable0.48to0.65Variable0.48to0.63Variable0.50to0.70Variable0.45to0.63LensResolution0.40m0.30m0.25m0.28m0.18m0.15m0.150-130mFieldSizeDiameter31.1mm31.1mm31.1mm26*33mm26*33mm26*33mm26*33mmOverlay2pt.GlobalAlignment60nm45nm45nm45nm40nm35nm40nmThrupt200mmwafers72wph70Exp.200mJ/cm293wph70Exp.200mJ/cm288wph70Exp.30mJ/cm2104wph46Exp.200mJ/cm2115wph46Exp.30mJ/cm2120wph46Exp.30mJ/cm260wph46Exp.10mJ/cm2*DatacollectedfromASMLLithographySystemI-lineStepper•IlluminationSource•IlluminationSystem•DoseControlSystem•ReticleHandlingSystem•ReductionLens•WaferHandlingSystem•WaferStage•AlignmentSystem•FocusandLevelingSystemSub-systemsLithographySystemIlluminationSystemLithographySystemOAI-apertureStopAnnularQuadrupoleConventionalLithographySystemReductionLensDioptricDesignCatadioptricDesignLithographySystemTheImplicationofNAAsmallerobjectspreadslightmore.Alargercap