Topography-Aware OPC for Better DOF margin and CD control.ppt

Topography-AwareOPCforBetterDOFmarginandCDcontrolPuneetGupta*,*†‡,Chul-HongPark†,KambizSamadi†,andXuXu‡*Blaze-DFMInc.†,SanDiego‡,SanDiegoMotivationThedepth-of-focusvariationcorrespondingtothicknessvariationseverelyaffectsthemetalpatterningofthesubsequentupperlayerStandardOPC(SOPC)assignszerodefocusforeachlayerwhichwillleadtoCDvariationofthemetalfeaturethatwillbeplacedonthatlayerTopography-awareOPC(TOPC)ordingly(a)Sideviewshowingthicknessvariationoverregionswithdenseandsparselayout.(b)TopviewshowingCDvariationwhenalineispatternedoveraregionwithunevenwafertopography,.,-CMPtopographyvariationisrequiredOriginallayoutandsimulationresultwithzeroDOFmodelOriginallayoutandsimulationresultwith--planartopographyStandardOPClayoutandsimulationresultwithzerodefocusmodelStandardOPClayoutandsimulationresultwith--planartopographySOPCSimulationResults(c)(d)OriginalmetalOPClayerResistImage(b)--(a)pensateCDvariationinducedbytopography!!-AwareOPCandORCOPCMethodORCMethod∆CD()STDSTD0STDT-A>0T-ASTD>0T-AT-AbinationsofOPCandORC(STD,andT-AstandsforStandardandTopography-awaremethodologies,respectively)STDOPC/ORCwillgenerateasmallCDerror,butthepremiseofthismethodisatfaultSTD-OPC/T-A--A-OPC/STD-binationdoesnotmakesense!T-A-OPC/T-A-ORCyieldsasmallCDerrorandconsiderslayerswithuneventopographyK-ordingtoitsheightHowever,assigntwofeatureswithinthedistanceofRtodifferentDMLPartitionwillresultinOpticalErrorObjective:ordingtoheightDistance<RModifiedAssignmentk-putethepost-workflowtopologywithvertexvforeachfeatureandanedgebetweentwocloseverticesfor(i=1;i<k;i++)CalculateedgecapacitancesSolvethemaximumS-TflowproblemAllverticesontheSsideofthecutareassignedtoDMLiST110Maxflow=1Mincut=ordingtoDMLTOPC