半导体工艺ppt课件

IC工艺技术系列讲座第二讲PHOTOLITHOGRAPHY光刻.讲座提要1.General2.Facility(动力环境)3.Mask(掩膜版)4.Processstephighlight(光刻工艺概述)5.BCD正胶工艺6.Historyand未来的光刻工艺.1.GeneralMASKINGProcess(光刻工艺)Photolithography(光学光刻)----Transferatemporarypattern(resist)DefectcontrolCriticaldimensioncontrolAlignmentaccuracyCrosssectionprofileEtch(腐蚀)----Transferapermanentpattern(Oxide,Nitride,Metal…).2.0FacilityrequirementTemperature(温度)70oFHumidity(湿度)45%Positivepressure(正压)>0.02in/H2OParticlecontrol(微粒)Class100Vibration(震动)Yellowlightenvironment(黄光区)DIwater(去离子水)17mhomCompressairandNitrogen(加压空气,氮气)Inhousevacuum(真空管道).3.0Mask(掩膜版)DesignPGtapeMaskmakingPlate---quartz,LEglass,SodalineglassCoating---Chrome,Ionoxide,EmulsionEquipment---E-beam,PatterngeneratorMaskstorage---AntistaticBox.Pellicle.Pellicleprotection.4.0光刻工艺概述PrebakeandHMDS(前烘)Resistcoating(涂胶)EBR(去胶边),softbake,3.Exposure(曝光)Alignment(校正)4.Develop(显影)Poste-bake,Hardbake,backsiderinse5.Developinspection(显检).4.1PrebakeandHMDStreatmentPurposeofPre-bakeandHMDStreatmentistoimprovetheresistadhesiononoxidewafer.HMDSisadhesionpromoterespeciallydesignedforpositiveresist.HMDS(Hexamethyldisilane)canbeappliedonthewafersby1.Vaporinabucket2.vaporinavacuumbox3.Directlydispenseonwafer4.YESsystem---inahotvacuumsystem5.Vaporinahotplate(withexhaust)ToomuchHMDSwillcausepoorspin,viceversawillcauseresistlifting.4.2ResistCoating(涂胶)Resistcoatingspecification(指标）Thickness（厚度）0.7u–2.0u(3.0以上forPadlayer)Uniformity（均匀度）+50A–+200ASizeofEBR（去胶边尺寸）Particle（颗粒）<20perwaferBacksidecontamination(背后污染）三个主要因数影响涂胶的结果ResistProduct(产品）Viscosity（粘度）SpinnerDispensemethod（涂胶方法）Spinnerspeed(RPM)（转速）Exhaust（排气）Softbaketemperature（烘温）FacilityTemperature（室温）Humility（湿度）.4.2.1Coater(涂胶机）EquipmentmoduleandspecialfeaturePre-bakeandHMDS---Hot/ColdplateResistdispense---ResistpumpRPMaccuracy---MotorEBR---Top/bottomHotplate---softbaketemperatureaccuracyExhaustWastecollectionTemperature/HumiditycontrolhoodTransfersystem---ParticleandreliabilityProcessstepandprocessprogram---Flexible.SVG8800升降机涂胶HMDS热板冷板升降机升降机升降机涂胶热板热板升降机升降机升降机升降机涂胶热板冷板HMDS冷板冷板冷板涂胶热板热板升降机升降机显影热板热板热板冷板4.2.2Coater(涂胶机）combination.4.2.3Coater(涂胶机）ResistdispensemethodsStaticDynamicRadialReverseradialResistpump(Volumecontrol---2cc/waferanddripping)Barrelpump---TritekDiaphragmpump---MilliporeN2pressurecontrolpump---IDLStepmotorcontrolpump---Cybotsizeofdispensehead.4.2.4Coater(涂胶机）rpm(转速）andacceleration（加速）Maximumspeed---Upto10000rpmStability---daytodayAcceleration---controllablenumberofstepsReliability---timetoreplacementEBR(Edgebeadremoval)（清边）Method---TopEBRorBottomEBRorTopandbottomEBRProblem---DrippingChemical----Acetone,EGMEA,PGMEA,ETHLY-LACTATE.ResistTypeNegativeresistPositiveresistG-linei–linereverseimageTAC---topanti-reflectivecoatingBARLI---bottomanti-reflectivecoatingChemicalamplificationresistXrayresist.4.3.1Exposure(曝光)Transferapatternfromthemask(reticle)toresistGoal1.CriticalDimensioncontrol(CD)条宽2.Alignment校准---Mis-alignment,runin/out3.Patterndistortion图样变形---Astigmatism4.Crosssectionprofile侧面形貌---sidewallangle5.Defectfree无缺陷Equipment/mask/resistselection1.Resolution分辨率---Exposecharacter,Lightsource(wavelength),N/A,2.Auto-alignmentskill自动校准技术---Lightfield,darkfield,laser3.Mask掩膜版---e-beammaster,sub-master,spotsize,quartzplate,defectdensity,CDrequirement4.Resistselection胶选择.4.3.2Exposure(曝光)AlignerTechnology1.Contactprint(接触）Softcontact,hardcontact,proximity2.Scanner(扫描）3.Stepper(重复）1X,2X,4X,5X,10X4.Step–Scan(重复扫描)4X---reticlemove,wafermove,reticle/wafermove5.Xray(X光）1:16.E-beam(电子束）---Directwrite.4.3.3Exposure(曝光)Contactprint(接触）1.Mostofusefornegativeresistprocess---for5uprocessandcanbepushto3u.2.Positiveresistcanprintsmallerthan3u,anddeepUVcanpushto1u,butveryhighdefect3.Equipment:---CanonPLA501---Cobilt---Kasper---K&S.Contactprint---Canon501.4.3.4Exposure(曝光)Scanner(扫描）1.MostofuseforG–linePositiveresistprocess---for3uprocessandcanbepushto2u.2.Negativeresistcanprintsmallerthan4u3.Equipment:---CanonMPA500,600---PerkinElmer100,200,300,600,700,900.PE240Scanner.Canon600Scanner.4.3.5Exposure(曝光)Stepper(重复）1.Glinepositiveresist---for<0.8uprocess2.ilinepositiveresist---<0.5uprocess3.ilineresistplusphase-shiftmask---canbepushedto0.354.deepUVresistprocess---0.35uandbelow5.Equipment:---Ultratech---Canon---Nikon---ASML.4.3.6Exposure(曝光)6ASMLStepperlistModelWavelengthResolutionASML2500g0.8ASML5000ASML5500–20,22,25,60,60B,80,80Bi0.55ASML5500–100,100C,100D,150i0.45ASML5000–200,200B,250,250BUV0.35ASML5500–300,300B,C,D,TFHUV0.25ASML5500-900Step-ScanUV.4.4.1Develop(显影）Developprocess1.Postexposebake2.ResistDevelop3.DIwaterrinse4.HardBakeDevelopequipment1.Batchdevelop2.Trackdevelop　Developchemical1.KOH2.Metalfree(TMAH)---Tetramethylamoniahydroxide3.Wettingagent---with/without4.Concentration---2.38%TMAHTrackdevelopmethod1.Spray2.Steam3.Signal-Paddle4.Double-Paddle.4.4.2Develop(显影）DevelopTrack1.TemperaturecontrolwaterjacketforDevelopline2.Developpump/developpressurecanister3.Exhaust4.Hotplatetemperaturecontrol5.Pre-wet---processprogram.4.4.3Develop(显影）CDcontrolindeveloping1.Postbakeprocess2.DevelopTime3.Concentrationofdeveloperchemical(Higherfast)4.Developertemperature(lowerfaster~1oC/0.1u)5.Developrecipe---pre-wet,paddle,rotation6.Ageofthedevelopchemical7.Rinse---DIwaterpressure8.Hardbaketemperature.4.5.1DevelopInspectionToolforinspection1.MicroscopeManuallyloadingAutomaticloading2.UVlampManuallyloadingAutomaticloading3.CDmeasurementequipmentManuallymeasuringsystem---Vicker,Automaticmeasuringsystem---NanolineCDSEM.4.5.2DevelopInspectionInspectionitems1.Layername2.Alignment3.Runin/out4.Patterndistortion5.Patternintegrity6.Defectslifting,particle,discoloration,scumming,bridging,excessresist,scratch7.CD(criticaldimension).Nanoline---forCDmeasurement.Hitachi8860---CDSEM.LeitzMicroscopeinspectstation.AutoloadUVinspectionsystem.5.0BCD正胶工艺EquipmentSSI,SVG8800,SVG90Processsteppre-bake/HMDS/coldplatespin(<5000rpm)---dynamicdispense---top(bottom)sideEBR(2mm)softbake(100oC)/cold/palteResist/specShipley6112(1.2u)1818(1.8u1stmetal)6818(2.4u2ndmetal)6118(2.9uPad)6124(3.6u-4.5uST)Everlight533(1.2)Uniformity---+300AResistcoating升降机冷板HMDS涂胶热板冷板升降机.SVG90.SVG8800.5.1.1PositiveResist(正胶）Component(成分）Resin（树脂）Diazonaphthoquinone(DNQ)/novolakPhoto-sensitizer（感光剂）Solvent（溶剂）Dye（染料）Manufacturing(制造商）Kodak–Hunt–Ashchemical(USA)TOK(Japan)JSR(Japan)Shipley(USA)AZ(USA,Germany)Sumitomo(Japan)Everlight(Taiwan).5.1.2PositiveResist(正胶）ProductNameandfeature(产品称与特性）以everlight(永光）正胶为例ProductSeriesEPG510SeriesExposewavelengthG-Line(435nm)ThicknessName2000rpm5000rpmViscosity（粘度）EPG510---12cp1.25u0.80uEPG512---21.5cp2.00u1.25uEPG516---50cp3.25u2.00uEPG518---105cp4.50u2.75uEPG519---460cp9.00u5.5uResolution(分辨率）0.8u(0.55u---thesmallest)DepthofFocus(聚焦深度）+1.4u(1.0uline/space)Sensitivity(感光度）Eth=60mj/cm2Eop=90mj/cm2.5.1.4PositiveResist(正胶）Selectapositiveresist1.Resolution（分辨率）2.Resistthickness---Spincurve（厚度）3.Photospeed(曝光速度)4.Exposelatitude(曝光宽容度)5.Adhesion（粘附性）6.Reflectivenotch（反射缺口）6.Metalliccontent（金属含量）7.Thermalstability（热稳定性）8.Plasmaresistance（抗腐蚀能力）9.Howeasytoberemoved（清除能力）10.Price（價格）.5.2ExposeEquipmentUltratechstepper1100–(6”)Ultratechstepper1500–(6”)Canon600–(6”)PerkinElmer240–(4”).PositiveResistreactionduringexpose.PositiveResistreactionduringexpose.5.2.1UltratechStepperUltratechstepperG-lineN/A---0.24and0.311:1printratio3X5inchreticle---3,4,5,7field4udepthoffocusBlindstepcanbepushto<5u(nospec)Centerofarray<+50uDarkfieldalignmentSitebySitealignmentAlignmenttarget*oat---4mmX4mm*K/T---200uX200u.UltratechStepper1100.UltratechStepper1500/1700.5.2.2Ultratchstepperspecification.UTS---ReticleandJobfileGuideFiducials.UTS---primarylens.UTSAlignmentOptic.Ulratechsteppersitebysitealignment.UTalignmentprocedureLoadjobfileintocomputerLoadreticle　　　　StartＦiducialsalignment---Guide,rotation(1500)OATalignmentOATsize=4mmX4mmFastandslowscan1000uSidebysidealignmentKeyandtargetsize200uX200ushotscan20ulongscan100u(80u)Auto-focusGobleorlocalFailurealignmentSkipExposeZmode.5.3PerkinElmeralignerMicalignPE100MicalignPE200,220,240MicalignPE300,340,340HTMicalignPE500MicalignPE600MicalignPE700MicalignPE900Micscan100Micscan200Micscan300Micscan400.PE240Specification.PE240.PE240PMCenterofcurvatureParallelismLightintensityFocusDistortionMask/wafercenteringViewopticHPCrebuildCoolingairflowrateVibrationfromHPCFacilityVibrationfromenvironmentTemperaturecontrolhoodProcessReferencewaferApertureselectionResistbuilduponXYOpinsRoofmirrorcleaningMaskheatupduringexpose.PE---Focuswedgemask.PE---distortion.PE---Projectionoptic.PEMercurylamp.PE---Adjustableslit.PEalignmentprocedureSetscanLoadmaskLoadwaferSwitchtomaskUsemicroscopeandcarriagemovementtofindthealignmentmarkonmask(Testdie)MovemaskonlytoalignthewaferSwitchtowaferMovewaferaligntomask.5.4.1ResistdevelopEquipmentSSI,SVG8800,SVG90Processsteppose-ebake/coldplatedevelop---doublepaddle---DIwaterrinse---backN2/rinsehardbake(110-130oC)/cold/palteDeveloperTMAH2.35%升降机冷板热板冷板升降机热板显影.SVG8800.SVG90.5.4.2ResistdevelopEquipmentDevelopsinkEquipmentsetupTemperatureN2blanketFiltersizeFilterchangeDeveloperTMAH2.38%DevelopchangeProcessstepbatchdevelop---immerse(1’&15”)QDRDIwaterrinse(8cycles)hardbake(110-130oC)/cold/palte.6.Historyand未来的光刻工艺Willimprinttechnologyreplacephotolithography?In1798,imagewastransferredbystoneplate1940,BellLabusedresistdevelopedbyEastmanKodak1960,SanFranciscobayareabecomesthesiliconvalley---AT&T,Raytheon,Fairchild,Negativeresist–contactprintprocesswildlywasused.Endof1970-earlyof1980,positiveresist–Projectionprint(PerkinElmerMicalign)startedtobeusedinproduction.Bayareabecamecloudy---National,IntelandAMD.OutsidebayareahadMotolora,TI,IBM.From1970toearly2000,thetechnologyofsemiconductorisdevelopedveryfast.Thesmallestfeaturesizefrom10ureducedto0.09u.0.25uand0.35uproductswererunningmassproductioneverywhere---USA,Europe,Japan,Taiwan,Korea…i-line,anddeepUV---5Xstepperandstep-scan(4X)alignerbecamethemajortools.Now,0.09utechnologybecomemature.0.065u,0.045uand0.035utechnologyarebeingdeveloped.Immersionlithographyandimprinttechnologywillbeusedtoprintthesenanofeature.Imprinttechnologyclaimsthatitisabletoprint0.01u(10nm)---Itmaybethefuturemasking..6.1HistoryLithography,asusedinthemanufactureoftheintegratedcircuit,istheprocessoftransferringgeometricshapesonamasktothesurfaceofasiliconwafer.Theseshapesmakeupthepartsofthecircuit,suchasgateelectrodes,contactwindows,metalinterconnections,andsoon.Althoughmostlithographytechniquesusedtodayweredevelopedinthepast40years,theprocesswasactuallyinventedin1798;inthisfirstprocess,thepattern,orimage,wastransferredfromastoneplate(thewordlithocomesfrom).Thefirstpracticaltwodimensionaldevicepatterningonasiliconwaferwasactuallycarriedoutinthelate1940sattheBellLab.Atthattime,polyvinylcinnamate,developedbyEastmanKodak,wasusedasaresist.However,deviceyieldswerelowbecauseofthepooradhesionofthepolyvinylcinnamatetothesiliconandoxidesurface.TheKodakchemiststhenturnedtoasyntheticrubberbasedmaterial---apartiallycyclizedisopreneandaddedaUVactivesensitizer---abis-aryl-azideintoittocrosslinktherubbermatrixandcreatedanewclassofphotoresistmaterial.Sincetheunexposedareaofthenewmaterialwastheonlypartofthepolymermatrixthatwilldissolveinanorganicsolventandyieldinganegativeimageofthemaskplate,therefore,thenewmaterialwasthenreferredasthenegativeresist.Thecyclizedrubber/bisazideresistwaswidelyusedinthecontactprintingage.However,thecontactmodeofprintingcreatedseverewearofthemaskplateandthedefectdensityofthephotomaskandthewaferwasveryhigh.Theindustrythereforedecidedtoswitchtocontactlessprojectionprintingin1972forproducingthe16kDRAM.Projectionprinting,however,wascarriedoutintheFraunhofferorthesocalledfarfielddiffractionregionandtheaerialimagewasmuchpoorerthanthecontactorproximitymethodofprinting.Inordertopreservethesamequalityofimagestructure,thecontrastoftheimagematerialmustbeincreased..Lithographiclorehasitthatthediazonaphthoquinone/novolakresist(thetermnovolakisderivedfromtheSwedishwordlak,meaninglacquerorresinandprefixedbytheLatinwordnovo,meaningnew)madetheirwayfromtheblueprintpaperindustrytothemicroelectronicthroughfamilyties:atthattimes,theofficesofAzoplate,theAmericanoutletforKalleprintingplate,waslocatedatMurrayHill,NJ,justacrossthestreetfromthefamousBellLabs.ThefatherofatechnicianatAzoplateworkedasatechnicianatBellLabs.ApparentlythefatherhadcomplainedonedayaboutthepoorresolutionqualityofthesolventdevelopedresistsystemusedattheBellLabsandthesonhadboastedthepropertiesoftheAzoplateDNQ/novolakmaterial;anyway,onedaythefathertookabottleofthematerialwithhimtotheBellLabs,andtheageoftheDNQ/novolakresistbegan.ThenewmaterialwasmarketedbyAzoplateunderthetradenameofAZphotoresist.Itwasalwaysreferredasthepositiveresistforapositivetoneofimagewouldbereproducedbythenewmaterial.TheuseofDNQ/novolaksystemincreasedrapidlyaftertheintroductionoftheprojectionlithography.By1980s,theDNQresisthadcompletelysupplantedtheoldnegativeresistastheworkhorseofthesemiconductorindustryinthehigh-endapplications.TheDNQ/novolakresisthasheldswayfor6devicegenerations,fromtheintroductionofthe16KDRAMtothelargescaleproductionofthe64MDRAMin1994to1995.Thesuccessofsuchmaterialwastheindicativeofitsupremeperformanceandpotential.Today,itappearsthatitisnotreallytheresolutionwhichdefinesthelimitoftheDNQ/novolakresistapplication,butratherthelossinthedepthoffocuswiththeeverincreasingNAofthestepper.DeepUVandchemicalamplificationnegativetoneresistslowlyerodethemarketplaceoftheDNQ/novolakresist.Bytheendofthe1990s,theDNQ/novolakresistwasnolongerbeusedinthetechnologicallymostadvancedapplications---theprintingofthecriticallevelsofthe256MDRAM..6.2FutureIntroductionofnanoimprinttechnologyFabricatingmicrostructuresandnanostructureisimportantinmanyfieldsofscienceandtechnology,includingelectronics,datastorage,flexibledisplays,microelectromechanicalsystems,microfluidics,photonicsandbiosensors.Traditionally,opticalorelectronbeamlithographysystemsareusedtoprinttherelevantstructures.However,newprintingmethodssuchasimprintlithographyandsoftlithographyhaverecentlybeenexploredinsomedetailtolowerthecostsoffabricatinglowvolumesofstructureswithverysmallfeaturesandtoincreasetherangeofprintingapplication.Thesoftlithographyschemes,ingeneral,useasofttemplatepatternmadeofsiliconeelastomer,polydimethylsiloxane(PDMS),whichisplacedintocontactwiththesubstrateinavarietyofways,topatternasurfacefilm,totransferamaterial,orfordirectintegrationintothefinalpart,witharangeofinnovativeapplications.ChallengesinthisareaaregenerallyconcernedwiththeinherentlimitationsofthePDMSmaterialincludingresolutionlimitationswhencuringduetodifferencesinthermalexpansionbetweenthemasterandmold;adhesiontocommonmastermaterialslikesilicon;significanttime,aboutanhour,tofabricateamold;elasticityofthemold,whichmayimpactmultilevelalignment;insolubilitywithcommonsolvents;contaminationissuesandincompatibilitywithsomeorganicmaterials..TheimprintmethodsutilizeheatorUVcurableliquidstomoldpatternsontoasubstratefromarigidtemplate.Researchgroupshavedemonstratedsub-100nmresolution,somehavedownto10nm.Imprintprocess;however,donottransfermaterialsfromthetemplatetothesubstratelikethesoftlithographyschemes.Anotherhesitationwiththeimprinttechniqueconcernsthelifetimeofthemasterpattern.Theproblemissimilartothatencounteredinthecontactphotolithography,whereithasbeenfoundthatthedefectfreelifetimeisonlylimitedtolessthan1000passes,despitetheapplicationofcoatingsandlubricants.Thisconcernarisesfromtheimportantrequirementsthatthesubstratemustundergosignificantcontactandremovalforces,thatarigidmasterpatternisusedandthatatoolisrequiredtoachievegoodimprints.InStanfordUniversity,anewclassofhighresolutionpatternformationandmaterialstransferprintingstrategyhasbeendeveloped.Thisnewmethodiscollectivelyreferredtoasmoleculartransferlithography.Thenewapproachisbasedontheroomtemperaturefabricationofwatersolublepolymertemplatesbyspincastingapolyvinylalcoholfilmformingsolutiontoreplicatesurfacepatterns.Itisdifferentthantheimprintlithographyandsoftlithographybyemployingawatersolubletemplate.Thetemplatedissolvesattheconclusionoftheimagetransfer,whereasinthealternativeapproaches,thetemplateisreused.Theuseofthewatersolubletemplateforpatterningmicrostructureandnanostructurefeaturesenablesatruecontactprintingmethodwhereinthemastertemplatedoesnotactuallycontactthesubstrateandthepossibilityofsubstratetomaskdamageiseliminatedandtheintegrityofthemasterpatternispreservedduringthereplicationprocess..