Litho-Process-Training教学讲解课件

LithographyProcessTraining5.Lithoprocesssetupandevaluation4.LithoOptics3.MaskIntroduction2.LithoProcess

keyparameterintroduction1.GeneralintroductionOutline

GeneralintroductionMaterialneededforLitho？ 1.PhotoMask(Reticle） 2.Scanner/Stepper 3.Track(Coating,Developing) 4.Lightsource（DUV,I-line,g-line） 5.PhotoResist6.DeveloperInspectionandmetrologytool：1.CD:(Hitachi9220/9260)2.Overlay:(KLAArcher5/Archer10)3.ADI:(Nidek800/Nikon)4.DefectScan:(KLA2351/2360)Scanner/StepperModelExposureStepMethod1.StepperMachine: Nikoni112.Scanner

Machine: ASML700/850

LightSource：1.I-Line: 365nm(Hg-Arc)Machine:

Nikoni112.DUV: 248nm(KrFLaser),193nm(ArFLaser)

Machine: ASML700/850

AT1250/1400

ScannerOverview:(ASML)optionalQuadrupole

bladeANNULARITYCONTROLZOOMLensinoutZOOMlens:CoherenceSIGMAModule:Annularityin,outIlluminator

AERIAL’sZoomAxiconFixedpartMovingpartouterinnerco-axial

conics‘wedges’‘planeplate’AERIAL’sZoomAxicon64ProjectionLensStepperandScannerStepperScannerStepperScannerExposurePrinciple

StepperScannerShot:scanner/stepperstandardexposurefiledDie:minimumeffectivecircuitchipMask(Reticle)SideViewWaferStageandReticleStageLightSource:

DUV=248nm,I-line=365nm,g-line=436nmCymerlaserLambdaphysikMercurylampLightsourceoverviewTrackOverview(TELACT-8)TrackUnitOverviewCoaterUnitDeveloperUnitE2E3HSHDevelopNozzleType2.LithoProcess

keyparameterintroductionStandardLithoProcessWaferFlow(1)StandardLithoProcessWaferFlow(2)PRDeveloping52sPuddle,45sRinse

HardBake110ºC60SCooling23ºCSiBaseIMDFilmSiBaseIMDFilmSiBaseIMDFilmEtchingSiBaseIMD+++++++e-e-e-e-e-IonPlasmaSiBaseIMDFilmSiBaseIMDFilmCDMeasurementCDCuCuIMD1

SiBaseIMD2PRPROVLMeasurementADIinspectionFor

designrule:L/S=130/140nm(Pitch=0.27um)ResolutionExposureLatitudeDepthofFocus

(DOF)ProximityBiasLinearityLine-edgeRoughnessLineEndshorteningAspectRatioResistfilmlossCDuniformityEtchSelectivityMicro-lithographyKeyparameterPRSiON

FSGLSPitch=L+SLithoOpticsSiN

LithoChemistryMicro-lithographyKeyTechnologies

,resolutionOAI-obliqueillumination-0th/1stordercollected-enhancedensefeatures-combinedw/SBOPCtoimproveisolatedfeaturesPSM-180ophaseinterference-HTPSMand

LevensonPSMOPC-CD+processwindowResist-dependonpatternandilluminationcondition

Reflection-importantforgoodCDcontrol

CD（CriticalDimension）:LineWidth,SpaceWidthorHoleDiameterofspecifieddesignedpatterntomonitorphotoprocessconditionandresolutioncapability.ToshrinkCDsizeIncreaseNADecrease

RETisnecessaryRET(ResolutionEnhancementTechnology)OAI,PSM,OPC…AsCDsizesmaller,theprocesswindowisnarrow,itmakeprocesscontrolmoredifficultEquipmentOptimizeCD

ITRSRoadMap

OverlayOverlayOuterMarkOverlayInnerMarkTwoCriterions:CDv.s.Overlay3.MaskIntroductionMaskBlankComponent

BinaryBlankPSMBlankPhotoResistChromeOxideChromeQuartzPhotoResistChromeOxideChromeQuartzMoSiFilmSubstrateOpaqueMetalFilmPhotoResistSubstratePhaseShiftLayerOpaqueMetalFilmPhotoResistPellicleComponent

PellicleMembraneMaterialWaveLengthN.C.350~450C.E.365,436F.C.248,365;193,248Frame(AluminumAlloy)AdhesiveTapePellicleMembrane(2~5um)PellicleFrameDoubleSideAdhesiveTapeCrGlassPellicleContributionTopContaminantObjectPlanePellicleFilmBottomContaminantContaminantonPatternPlaneLenSystemUnfocusedTopContaminantImageUnfocusedBottomContaminantImageImagePlaneFocusedContaminantImageonWaferMaskPatternWaferSurfaceLightTransferDesigntoMaskWriterProcessMetrologyVis-InspectClean/MountAIMSRepair1stInspectThr-InspectSTARlightShippingDevelopStripEtchReticle

FrameReticleEngineeringSpecification4.LithoOpticsIlluminationtheoryRETtechnologyOpticalProcessErrorIlluminationtheoryResolution

DepthofFocusk1andk2areprocessdependent,andNAisDefinedintheimageside(waferside)TradeoffmustbemadewhenincreasingNA.NA(NumericalAperture)andSigmaKöhlerilluminationExampleofResolution

DepthofFocus(DOF)Ingeneral,DOFcanbethoughtoftherangeoffocuserrorsthataprocesscantolerateandstillgiveacceptancelithographicresults.AsampledefinitionofDOF:therangeoffocusthatkeepthelinewidth,sidewallangleandresistlosswithintheirstatedspecifications.0.40.3Linewidth[µm]-1.5-1.0-0.50.00.51.01.5Focus[µm]DOFdoseE1:1Projectiondesignequations-BossungCurve(UDOF)EL=2.Emax-EminEmax+EminExposuredose[%]EmaxEminE1:Linewidth[µm]8090100110120nom.CD+10%nom.CD-10%stronglyFocusdependentLinewidthvs.Exposure,atdifferentfocussettingsFocus1Focus2Focus3Projectiondesignequations-ExposureLatitudeProjectiondesignequations-Exposure-Defocus(E-D)WindowDOFexampleDoFOptimizeConventionalillumination:

3beaminterferencelowDOFPhaseShiftMask:

2beaminterferencehighDOFOff-axilIllumination:

2beaminterferencehighDOF(atoptimizedfeaturesizeonly!!)

Imaging=1.lightdiffractedatreticle=split-upinFouriercomponents;smallstructures givewidesplit-up2.transmittingdiffractionordersthroughthelens:resolutioninformationisin +1diffractionorders(gratings)ImprovingImage=1.keeping+1ordersinlensmethods: a)decrease b)increaseNA c)increase d)offaxisillumination2.OptimizingcontrastandDOF:

findbestcombinationofNA,,forgivenfeature(s)IlluminationTheorySummaryRETTechnology1.ApplicationofPSM(Phaseshiftmask)Physicalphenomena:PhaseshifterElectricFieldDirectionofLightPropagationan1n2PhasedelayoftransmittancelightisproportionaltomaterialthicknessWithgoodthicknesscontrol,thephasedelaycanbecontrolledtobeπ

d=λ

/2(n-1)

Φ

=2π

(n-1)d/λ

PhaseAngledPhaseShifterTheprincipleofPhase-ShiftMask2.Off-axisilluminationTypeofoff-axisilluminationAnnularQuasarwafer-2order-1order+2order+1order0orderreticlelens-1/-2

order+1/+2

order0/+1

order0/-1

orderwaferIlluminationdifferenceonaxisoffaxisResolutionenhancementofoff-axisilluminationDepthoffocusisincreasedbyreducingtheangleoftheordersthatcarrytheimagetothewafer.onaxisoffaxisDoFincreaseofoff-axisilluminationSwingCurve3.Anti-reflectiveCoatingAnti-reflectiveCoatingReduceswingratioSignificantlyimprovesline-widthuniformityovertopographyIncreasedepthoffocusoflinesprintedovertopographySignificantlyimproves“across-wafer“line-widthuniformityBenefitsofARCReduceswingratioSignificantlyimproveslinewidthuniformityovertopographyIncreasedepthoffocusoflinesprintedovertopographySignificantlyimproves“across-wafer“linewidthuniformityOpticalProcessErrorResistToplossResisttoplossisthefailurethatthetopofresistlinetobemeasuredismoreorlesrounded.i.e.developedaway

Itoccursonlywithpositivedefocusing.MousebitingMousebitingiscausedbyalensdefect.Thisisaphenomenonwherea“bite”istakenawayoutofaline.T-Top/FootingT-TopisaprocessfailurewherethelinebecomesthinnerunderthetopT-Topismainlycausedbybakingtemperaturenotoptimization.Footingistheeffectthatthelineisthickeratthebottom.FootingismainlycausedbyammoniacontaminationandPEBtemperaturenotoptimization.Scumming

Itistheeffectthatthelinegraduallybecomeswideratthebottom.Itmayoccurswiththenegativedefocusing.Italsomaycausedbyammoniacontaminationorpoordeveloping/rinse.PatternCollapsePatterncollapsewillhappenifFnet

islargerthantheadhesionforcebetweensubstrateandresistandcohesionforceintheresist.Optimizebaking/PEBtemperatureandtimecanreduceandsolvethisissueResistpeelingItisaprocesserrorwherethelinebecomesothinorpooradhesionthatthestartfallingoverorpeelingout.Itmayoccurwithnegativedefocusing.ItalsomayoccurwithpooradhesionwhichcausedbyHMDSprimingissueorammoniacontamination.LineEdgeRoughness(LER)LineedgeroughnessqualifiesCDvariationoverasmallareaofaline.TheprecisedefinitionofLERvariesbetweendifferentSEMmeasurementtoolsandoperators.CDImpactwithLER5.LithoprocesssetupandevaluationLithoprocesssetupprocedureDARC(SiON)/BARCSwingCurve,n,kvalueSimulation.PhotoResistSwingCurveSimulation.Lithoilluminationcondition(NA/Sigma)Simulation.Photoresistthicknesstuning,post-etchPRremaincross-sectionconfirm.Processcommonwindowcheck,proximityeffectcheckonsplitilluminationcondition.ADICDtarget,pitch,maskbiasandilluminationconditionfinaldecision.Pre-OPCproximity,linearityandLES(line-endshorteningdatacollection.OPCoptic/resistmodelsetupandlithostandardSSAtableprovide.OPCModelfinalprocessingwithprovidedilluminationandproximity.OPCmodelperformanceverificationonpost-OPCverificationpattern.FinalLithoprocessconditionandOPCmodelimplementation.ScannerType:ASML850CDARC:SION600ÅPRTK:

4150Å(P6119)SB:115C/80SPEB:110C/115SReticleID:160AA(Binary)IlluminationMode:HalfAnnularNA:0.70

(K1=0.42)SIGMA:0.80/0.40ADIDesignRule:0.15um/0.30um

(Trench/Pitch)Metal/PolyLayerOPCmodelSetupcondition:IMD/BARCFilmStackSimulationDARC/BARCn.kvalueVSreflectivity2-DplotThk=600ÅDARC/BARC

filmreflectivitycurven=2.01k=1.02SwingCurveSwingTop:3450Å,4150Å,4800ÅSwingBottom:3800Å,4500Å,5200ÅSwingRatio:700ÅSwingCurve