KLA测量设备.pdf

KLA测量设备.pdf

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July28,2008CS20SystemOverview2confidentialSystemoverviewTheCS20isadefectinspectionsystemtargetedforunpatternedwafersotherthanmainstreamsilicon.Itincludesbothdarkfield（scatteredlight）andbrightfield（reflectedlight）modes,whichcanbeusedsimultaneously.Sometypicalsubstratesusedbyourcustomersare:

GaAssapphiresiliconcarbideGaNlayersonsapphireorSiCglassforimagersordisplayssilicon,forsmalldiametersormixeddiameters3confidentialOutline1.Systemoverview2.Datacollection3.Dataanalysis4.Applicationsrecipesa）Recipesforsavingimagesb）Defectsrecipesc）Roughnessrecipesd）Filmthicknessrecipes4confidentialSystemOverview5confidentialSystemoverviewapplicationsPrimaryapplications:

Imagecaptureforengineeringtroubleshooting-rawdata（imagefiles）canbeeasilysaved,unlikemostscatterometers.Particlemeasurements（countandsize）DefectdetectionandclassificationwithcustomdefectcategoriesSecondaryapplications:

SurfaceroughnessFilmthicknessuniformity（singlelayerfilmsonly）6confidentialKLA-TencorCandelaCS-SeriesProductsCS10ManualloadingCS20Cassette-to-cassetteXBeamDualLaser（405nm）forbestsensitivity;alsoofferedwithasingle632nmredlaserforuseonsensitivefilms7confidentialSystemoverviewhardwarelayoutAnopticalheadcontainingalasermovesfromwaferedgetowafercenter,whilethesampleisspinningupto5000rpm.Datafromoneormoredetectorsiscollectedatahighrate,thensavedand/oranalyzeddependingontherecipeinuse.Vacuumchucksandcenteringringsareavailablefordifferentwafersizes,andcanbechangedinabout15minutes.ThetopphotoisfromaCS10system,inwhichtheusermanuallyplacesthewaferontothecenteringringwithavacuumwand.TheCS20systems（bottomphoto）containaseparateflatfindingstationandtwocenteringringsonmoveablepaddles.Duringsequences,whileonewaferisbeingscanned,thenextwaferistakenfromthecassetteandalignedformoreefficientoperation.8confidentialSystemoverviewcircumferentiallaserpathThelaseranddetectorsaremountedinasinglemodulecalledtheopticalhead.Theheadisusuallyabout80to100umabovethewafersurfaceduringmeasurements.Fourtypesofdetectorsareavailable,andmultiplesignalscanbecollectedsimultaneously.PatentspendingScatteredLightTopographySpecular（reflectedlight）PhaseshiftPolarizerLaserDiode9confidentialDataAcquisition10confidentialDatacollectionsignalsEach“signal”isacombinationofonelasersettingandonedetectoroutput.Thesignalnamingconventionistousethelasersettingfollowedbythedetectorchoice.LasersettingsFilterscanbeplacedinthebeampathtochangethepolarizationofeitherlaser:

S,PorQ（electricfieldorientedinthewaferplane,perpendiculartoit,oralinearcombination）.DetectorchoicesSymbolDescriptionApplicablelasersettingScScatteredlightdetectorS,P,orQZcCircumferentialtopographyS,P,orQZrRadialtopographyS,P,orQSpSpecularreflectionintensitySorPSp2IntensityfromZdetector（similartoSp）SorPPh,qPhaseshiftbetweenSandP,orforeitherQFourA/Dchannelsareavailableforsimultaneoussignalcollection.Inasinglescan,onlyonelasercanbeselected,andonlyonepolarizationsetting.11confidentialDatacollectionsignalsSpecularandphaseshiftdetectorsReflectedintensityorphaseshiftZchanneldetectorQuadPSDyieldsZc,Zr,andSp2signalsScatteredlightdetectorPhotomultipliertube（PMT）directlyabovespotLaserSourceS,P,orQpolarizationTheangleofincidenceisabout60degreesfromnormal.Detectoroutputisreportedinpercentofdetectorrange.Theoutputinpercentcanbethoughtofasadetectorvoltage,orsimplyasignalstrength.Zsignalscanbenegativeorpositive.Othersignalsarealwayspositive.12confidentialDatacollectionZchannelsThepositionofthereflectedbeamisconstantforaflatsurface,butdeflectswhenthesurfacehastopography.Forpits,thesignallevelgoesbelowthebackgroundlevel,thenabovethenreturnstothebackgroundlevel.Forbumps,thesignalfirstgoesup,thendown,thenbacktothebackgroundlevel.13confidentialDatacollectionZchannelsTheZchanneldetectorworksbysensingchangesinthepositionofthereflectedbeam.NominalbeampositionDeflectedbeamposition1Deflectedbeamposition2Zcsignal2（0）Zcsignal1（0）Zrsignal2（0）14confidentialDatacollectionsamplingplanScanparametersdictatewhereonthewafermeasurementswillbemade.Thestepsizedeterminestheradialresolution.Eachcircularpathiscalledatrack.Inreality,thescanmovesinaspiralpath,buttheterminologyofstepsandtracksisretained.Thedatasamplingratedeterminestheangularresolution.Thesamenumberofmeasurementsaremadeoneachtrack.Thechoicesrangefrom1X（1024samplespertrack）to64X（65536samplespertrack）.Theusermayalsoselectthestartradiusandstopradiuspositionstolimitthemeasurementtoaportionofthewafer.Stepsize10umRadialresolutionAngularresolution15confidentialDatacollectionimagereconstructionOncecollected,signaldatamaybeviewedandsavedintheformofimages.Eachmeasurementpointbecomesapixelintheimage,andcanbeviewedinblackandwhiteorwithfalsecolorschemestoenhancethedisplay.Lowsignals（morenegativesignals）aredark,andhighsignalsarebright.Thisisasapphirewafer,withimagesoftheSp2signalandSScsignals.NotehowthechuckvacuumringscanbeseenintheSScsignal,butnotintheSp2signal.Sp2signalSScsignal16confidentialDatacollectionimagecloseupsThesoftwarecontainstoolsforengineeringuseinviewingimagefiles.Theimagescanbesynchronizedwhenviewingmorethanonesignalatatime.Theimagescanbemagnified.Contrastandcolorsettingscanbechangedwithoutaffectingunderlyingdata.Onthissapphirewafer,manydarkspotsareseenintheSp2signal.Defectsusuallydeflectthebeamawayfromthedetector,causingthesignaltobecomelower,ordarker.ThereforeparticlesarealwaysdarkdefectsintheSp2orSSpsignals.TheSZcsignalshowstwodistinctscratches.Whilenotthesameasmicroscopeviewing,theimagesareinsomewayssimilar.Theyareusefulforengineeringtroubleshooting,andtheimagescanbearchivedasrawdataorpublished（asjpegorbitmapfiles）.SZcsignalSp2signal17confidentialDataAnalysis18confidentialDataanalysisThesignaldatacollectedbytheCS20canbeanalyzedforseveraldifferentpurposes;theanalysisisdefinedbyarecipe.Recipesusuallyspecifybothscanconditionsandanalysisparameters.Anexceptiontothisisaspecialtypeofrecipeusedtocollectandsaveimageswithoutperforminganyanalysis.Analysisrecipescanbeusedtore-analyzepreviouslystoredimages.Thisiscommonlydonewhendevelopingandtestingnewrecipes.SaveimageswithRecipe1（ExpertMode）AnalyzeimageswithRecipe2View/saveanalysisoutput（usuallyalogfileandajpegfileofthescreendisplay）ScanandanalyzewaferwithRecipe2Scan,saveimages,andanalyzewaferwithRecipe219confidentialAnalysisreportResultsfromananalysisrecipearepresentedintheformofareport.Eachapplicationtypehasaslightlydifferentreport.Thisreportisfromadefectrecipe.Thelogfileisascrollablefilethatincludesasummaryaswellasthelocationsandsizesofindividualdefects.Itcanbesavedinseveralformats.Thedefectmapshowsallofthedefectlocationsgraphically.Theparetochartshowseitherdifferentdefecttypesordifferentparticlesizes.Thescreendisplaycanbecapturedasajpegfile.DefectlogfileParetochartDefectmap20confidentialAnalysisreportwithdieLogfileContainsatextbaseddiemapshowingcountsofalldefectsorselecteddefectsDefectMapControllimitscanbeappliedtothediebasedondefectcountswithinthedie21confidentialSoftwareoverviewengineeringmodeThisistheengineeringmodescreen,whichisusedforrecipedevelopmentandengineeringmeasurements.Functionscanbeselectedthroughpull-downmenusfromthemenubar,asshownhere.Somearealsoavailablefromthetoolbar.Recipesareselectedthroughapull-downlistontherightsideofthescreen.Scansoranalysisrunsareinitiatedthroughbuttonsontherightsideaswell.RecipeselectionToolbarMenubar,withonepull-downmenushownScanstartbuttonAnalysisstartbuttonPrintscreenbutton22confidentialSoftwareoverviewproductionmodeThisistheproductionmodescreen,whichisusedforcassette-to-cassettemeasurementsusingexistingrecipes,whicharespecifiedinsequences.Functionsonthisscreenarelimited,andincludeselectingsequences,accessingthesequenceeditor,changingwaferselections,andenteringlotidentificationinfo.23confidentialDefectAnalysisRecipes24confidentialDefectinspection?

DefectInspectionisamulti-stepprocess.?

Step1:

Scan?

Step2:

Detect?

Step3:

Classify?

Step4:

ReportUsethresholdingandstitchingtoseparatedefectsfrombackground.Usedefectparametersandteststoclassifydetectedfeaturesintodefecttypes.Choosebestdetectionchannelsandresolutiontocapturedefect.Displaysimplemap,counthistogram,andlogfile.25confidentialDefectdetectionDefectdetectedwithasinglechanneloracombinationofchannels;basedonthresholdsappliedtobackgroundlevels.OpticalSizePixelareacoveredbythedefectdetermined.OpticalShapeAspectratioandotherparametersofthepixelareaisdetermined.ReportSimplemapshowingdefecttypes,locations.SummaryreportofdefectcountsbinnedintouserdefinedS,M,Lsizeranges.Detailedreportofindividualdefects,sizesandlocations.OpticalSignatureClassificationdeterminedbycomparingappearanceinoneormoredetectorchannels.PositiveThresholdNegativeThresholdEventSignalintensityDefectanalysisoverview26confidentialHowdoyousetthedefectparameters?

Thisisonedefectinfourdifferentsignals,collectedsimultaneously.Adefecttypecanbedefinedtoclassifyalldefectsthataresimilar