半導體工藝Photo.ppt

1、b,1,IC工藝技術系列講座第二講,PHOTOLITHOGRAPHY光刻,b,2,講座提要,1.General2.Facility(動力環(huán)境)3.Mask(掩膜版)4.Processstephighlight(光刻工藝概述)5.BCD正膠工藝6.Historyand未來的光刻工藝,b,3,1.General,MASKINGProcess(光刻工藝)Photolithography(光學光刻)-Transferatemporarypattern(resist)DefectcontrolCriticaldimensioncontrolAlignmentaccuracyCrosssectionpro

2、fileEtch(腐蝕)-Transferapermanentpattern(Oxide,Nitride,Metal),b,4,2.0Facilityrequirement,Temperature(溫度)70oFHumidity(濕度)45%Positivepressure(正壓)0.02in/H2OParticlecontrol(微粒)Class100Vibration(震動)Yellowlightenvironment(黃光區(qū))DIwater(去離子水)17mhomCompressairandNitrogen(加壓空氣,氮氣)Inhousevacuum(真空管道),b,5,3.0Mask(

3、掩膜版),DesignPGtapeMaskmakingPlate-quartz,LEglass,SodalineglassCoating-Chrome,Ionoxide,EmulsionEquipment-E-beam,PatterngeneratorMaskstorage-AntistaticBox,b,6,Pellicle,b,7,Pellicleprotection,b,8,4.0光刻工藝概述,PrebakeandHMDS(前烘)Resistcoating(涂膠)EBR(去膠邊),softbake,3.Exposure(曝光)Alignment(校正)4.Develop(顯影)Poste

4、-bake,Hardbake,backsiderinse5.Developinspection(顯檢),b,9,4.1PrebakeandHMDStreatment,PurposeofPre-bakeandHMDStreatmentistoimprovetheresistadhesiononoxidewafer.HMDSisadhesionpromoterespeciallydesignedforpositiveresist.HMDS(Hexamethyldisilane)canbeappliedonthewafersby1.Vaporinabucket2.vaporinavacuumbox3

5、.Directlydispenseonwafer4.YESsystem-inahotvacuumsystem5.Vaporinahotplate(withexhaust)ToomuchHMDSwillcausepoorspin,viceversawillcauseresistlifting,b,10,4.2ResistCoating(涂膠),Resistcoatingspecification(指標）Thickness（厚度）0.7u2.0u(3.0以上forPadlayer)Uniformity（均勻度）+50A+200ASizeofEBR（去膠邊尺寸）Particle（顆粒）20perwa

6、ferBacksidecontamination(背后污染）三個主要因數(shù)影響涂膠的結(jié)果ResistProduct(產(chǎn)品）Viscosity（粘度）SpinnerDispensemethod（涂膠方法）Spinnerspeed(RPM)（轉(zhuǎn)速）Exhaust（排氣）Softbaketemperature（烘溫）FacilityTemperature（室溫）Humility（濕度）,b,11,4.2.1Coater(涂膠機）,EquipmentmoduleandspecialfeaturePre-bakeandHMDS-Hot/ColdplateResistdispense-ResistpumpR

7、PMaccuracy-MotorEBR-Top/bottomHotplate-softbaketemperatureaccuracyExhaustWastecollectionTemperature/HumiditycontrolhoodTransfersystem-ParticleandreliabilityProcessstepandprocessprogram-Flexible,b,12,SVG8800,升降機,涂膠,HMDS,熱板,冷板,升降機,升降機,升降機,涂膠,熱板,熱板,升降機,升降機,升降機,升降機,涂膠,熱板,冷板,HMDS,冷板,冷板,冷板,涂膠,熱板,熱板,升降機,升降

8、機,顯影,熱板,熱板,熱板,冷板,4.2.2Coater(涂膠機）combination,b,13,4.2.3Coater(涂膠機）,ResistdispensemethodsStaticDynamicRadialReverseradialResistpump(Volumecontrol-2cc/waferanddripping)Barrelpump-TritekDiaphragmpump-MilliporeN2pressurecontrolpump-IDLStepmotorcontrolpump-Cybotsizeofdispensehead,b,14,4.2.4Coater(涂膠機）,rp

9、m(轉(zhuǎn)速）andacceleration（加速）Maximumspeed-Upto10000rpmStability-daytodayAcceleration-controllablenumberofstepsReliability-timetoreplacementEBR(Edgebeadremoval)（清邊）Method-TopEBRorBottomEBRorTopandbottomEBRProblem-DrippingChemical-Acetone,EGMEA,PGMEA,ETHLY-LACTATE,b,15,ResistType,NegativeresistPositiveresi

10、stG-lineilinereverseimageTAC-topanti-reflectivecoatingBARLI-bottomanti-reflectivecoatingChemicalamplificationresistXrayresist,b,16,4.3.1Exposure(曝光),Transferapatternfromthemask(reticle)toresistGoal1.CriticalDimensioncontrol(CD)條寬2.Alignment校準-Mis-alignment,runin/out3.Patterndistortion圖樣變形-Astigmatis

11、m4.Crosssectionprofile側(cè)面形貌-sidewallangle5.Defectfree無缺陷Equipment/mask/resistselection1.Resolution分辨率-Exposecharacter,Lightsource(wavelength),N/A,2.Auto-alignmentskill自動校準技術-Lightfield,darkfield,laser3.Mask掩膜版-e-beammaster,sub-master,spotsize,quartzplate,defectdensity,CDrequirement4.Resistselection膠選

12、擇,b,17,4.3.2Exposure(曝光),AlignerTechnology1.Contactprint(接觸）Softcontact,hardcontact,proximity2.Scanner(掃描）3.Stepper(重復）1X,2X,4X,5X,10X4.StepScan(重復掃描)4X-reticlemove,wafermove,reticle/wafermove5.Xray(X光）1:16.E-beam(電子束）-Directwrite,b,18,4.3.3Exposure(曝光),Contactprint(接觸）1.Mostofusefornegativeresistpr

13、ocess-for5uprocessandcanbepushto3u.2.Positiveresistcanprintsmallerthan3u,anddeepUVcanpushto1u,butveryhighdefect3.Equipment:-CanonPLA501-Cobilt-Kasper-Kinthisfirstprocess,thepattern,orimage,wastransferredfromastoneplate(thewordlithocomesfrom).Thefirstpracticaltwodimensionaldevicepatterningonasiliconw

14、aferwasactuallycarriedoutinthelate1940sattheBellLab.Atthattime,polyvinylcinnamate,developedbyEastmanKodak,wasusedasaresist.However,deviceyieldswerelowbecauseofthepooradhesionofthepolyvinylcinnamatetothesiliconandoxidesurface.TheKodakchemiststhenturnedtoasyntheticrubberbasedmaterial-apartiallycyclize

15、disopreneandaddedaUVactivesensitizer-abis-aryl-azideintoittocrosslinktherubbermatrixandcreatedanewclassofphotoresistmaterial.Sincetheunexposedareaofthenewmaterialwastheonlypartofthepolymermatrixthatwilldissolveinanorganicsolventandyieldinganegativeimageofthemaskplate,therefore,thenewmaterialwasthenr

16、eferredasthenegativeresist.Thecyclizedrubber/bisazideresistwaswidelyusedinthecontactprintingage.However,thecontactmodeofprintingcreatedseverewearofthemaskplateandthedefectdensityofthephotomaskandthewaferwasveryhigh.Theindustrythereforedecidedtoswitchtocontactlessprojectionprintingin1972forproducingt

17、he16kDRAM.Projectionprinting,however,wascarriedoutintheFraunhofferorthesocalledfarfielddiffractionregionandtheaerialimagewasmuchpoorerthanthecontactorproximitymethodofprinting.Inordertopreservethesamequalityofimagestructure,thecontrastoftheimagematerialmustbeincreased.,b,68,Lithographiclorehasitthat

18、thediazonaphthoquinone/novolakresist(thetermnovolakisderivedfromtheSwedishwordlak,meaninglacquerorresinandprefixedbytheLatinwordnovo,meaningnew)madetheirwayfromtheblueprintpaperindustrytothemicroelectronicthroughfamilyties:atthattimes,theofficesofAzoplate,theAmericanoutletforKalleprintingplate,waslo

19、catedatMurrayHill,NJ,justacrossthestreetfromthefamousBellLabs.ThefatherofatechnicianatAzoplateworkedasatechnicianatBellLabs.ApparentlythefatherhadcomplainedonedayaboutthepoorresolutionqualityofthesolventdevelopedresistsystemusedattheBellLabsandthesonhadboastedthepropertiesoftheAzoplateDNQ/novolakmat

20、erial;anyway,onedaythefathertookabottleofthematerialwithhimtotheBellLabs,andtheageoftheDNQ/novolakresistbegan.ThenewmaterialwasmarketedbyAzoplateunderthetradenameofAZphotoresist.Itwasalwaysreferredasthepositiveresistforapositivetoneofimagewouldbereproducedbythenewmaterial.TheuseofDNQ/novolaksystemin

21、creasedrapidlyaftertheintroductionoftheprojectionlithography.By1980s,theDNQresisthadcompletelysupplantedtheoldnegativeresistastheworkhorseofthesemiconductorindustryinthehigh-endapplications.TheDNQ/novolakresisthasheldswayfor6devicegenerations,fromtheintroductionofthe16KDRAMtothelargescaleproductiono

22、fthe64MDRAMin1994to1995.Thesuccessofsuchmaterialwastheindicativeofitsupremeperformanceandpotential.Today,itappearsthatitisnotreallytheresolutionwhichdefinesthelimitoftheDNQ/novolakresistapplication,butratherthelossinthedepthoffocuswiththeeverincreasingNAofthestepper.DeepUVandchemicalamplificationneg

23、ativetoneresistslowlyerodethemarketplaceoftheDNQ/novolakresist.Bytheendofthe1990s,theDNQ/novolakresistwasnolongerbeusedinthetechnologicallymostadvancedapplications-theprintingofthecriticallevelsofthe256MDRAM.,b,69,6.2Future,IntroductionofnanoimprinttechnologyFabricatingmicrostructuresandnanostructur

24、eisimportantinmanyfieldsofscienceandtechnology,includingelectronics,datastorage,flexibledisplays,microelectromechanicalsystems,microfluidics,photonicsandbiosensors.Traditionally,opticalorelectronbeamlithographysystemsareusedtoprinttherelevantstructures.However,newprintingmethodssuchasimprintlithogra

25、phyandsoftlithographyhaverecentlybeenexploredinsomedetailtolowerthecostsoffabricatinglowvolumesofstructureswithverysmallfeaturesandtoincreasetherangeofprintingapplication.Thesoftlithographyschemes,ingeneral,useasofttemplatepatternmadeofsiliconeelastomer,polydimethylsiloxane(PDMS),whichisplacedintoco

26、ntactwiththesubstrateinavarietyofways,topatternasurfacefilm,totransferamaterial,orfordirectintegrationintothefinalpart,witharangeofinnovativeapplications.ChallengesinthisareaaregenerallyconcernedwiththeinherentlimitationsofthePDMSmaterialincludingresolutionlimitationswhencuringduetodifferencesinther

27、malexpansionbetweenthemasterandmold;adhesiontocommonmastermaterialslikesilicon;significanttime,aboutanhour,tofabricateamold;elasticityofthemold,whichmayimpactmultilevelalignment;insolubilitywithcommonsolvents;contaminationissuesandincompatibilitywithsomeorganicmaterials.,b,70,Theimprintmethodsutiliz

28、eheatorUVcurableliquidstomoldpatternsontoasubstratefromarigidtemplate.Researchgroupshavedemonstratedsub-100nmresolution,somehavedownto10nm.Imprintprocess;however,donottransfermaterialsfromthetemplatetothesubstratelikethesoftlithographyschemes.Anotherhesitationwiththeimprinttechniqueconcernsthelifetimeofthemasterpattern.Theproblemissimilartothatencounteredinthecontactphotolithography,whereithasbeenfoundthatthedefectfreelifetimeisonlylimitedtolessthan1000passes,despitetheapplicationofcoatingsandlubricants.Thisconcernarisesfromtheimportantrequirementsthatthesu