IC工藝技術(shù)2-光刻課件

IC工藝技術(shù)系列講座

第二講PHOTOLITHOGRAPHY光刻講座提要1. General2. Facility(動(dòng)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(lái)的光刻工藝1. GeneralMASKINGProcess(光刻工藝)Photolithography(光學(xué)光刻)----Transferatemporarypattern(resist)

Defectcontrol Criticaldimensioncontrol Alignmentaccuracy Crosssectionprofile

Etch(腐蝕)----Transferapermanentpattern(Oxide,Nitride,Metal…)3.0 Mask(掩膜版)

DesignPGtapeMaskmaking

Plate---quartz,LEglass,SodalineglassCoating---Chrome,Ionoxide,EmulsionEquipment---E-beam,PatterngeneratorMaskstorage---AntistaticBoxPelliclePellicleprotection4.1 PrebakeandHMDStreatment

PurposeofPre-bakeandHMDStreatmentistoimprovetheresistadhesiononoxidewafer.HMDSisadhesionpromoterespeciallydesignedforpositiveresist. HMDS(Hexamethyldisilane)canbeappliedonthewafersby 1. Vaporinabucket 2. vaporinavacuumbox 3. Directlydispenseonwafer 4. YESsystem---inahotvacuumsystem 5. Vaporinahotplate(withexhaust) ToomuchHMDSwillcausepoorspin,viceversawillcauseresistlifting4.2 ResistCoating(涂膠)Resistcoatingspecification(指標(biāo)）Thickness（厚度）0.7u–2.0u(3.0以上forPadlayer)Uniformity（均勻度）+50A–+200ASizeofEBR（去膠邊尺寸）Particle（顆粒）<20perwaferBacksidecontamination(背后污染）三個(gè)主要因數(shù)影響涂膠的結(jié)果Resist Product(產(chǎn)品）

Viscosity（粘度）Spinner Dispensemethod（涂膠方法）

Spinnerspeed(RPM)（轉(zhuǎn)速）

Exhaust（排氣）

Softbaketemperature（烘溫）Facility Temperature（室溫）Humility（濕度）4.2.1 Coater(涂膠機(jī)）EquipmentmoduleandspecialfeaturePre-bakeandHMDS---Hot/ColdplateResistdispense---ResistpumpRPMaccuracy---MotorEBR---Top/bottomHotplate---softbaketemperatureaccuracyExhaustWastecollectionTemperature/HumiditycontrolhoodTransfersystem---ParticleandreliabilityProcessstepandprocessprogram---Flexible4.2.3Coater(涂膠機(jī)）ResistdispensemethodsStaticDynamicRadialReverseradialResistpump(Volumecontrol---2cc/waferanddripping)Barrelpump---TritekDiaphragmpump---MilliporeN2pressurecontrolpump---IDLStepmotorcontrolpump---Cybotsizeofdispensehead4.2.4 Coater(涂膠機(jī)）rpm(轉(zhuǎn)速）andacceleration（加速）

Maximumspeed---Upto10000rpmStability---daytodayAcceleration---controllablenumberofstepsReliability---timetoreplacementEBR(Edgebeadremoval)（清邊）Method---TopEBRorBottomEBRorTopandbottomEBRProblem---DrippingChemical----Acetone,EGMEA,PGMEA,ETHLY-LACTATEResistTypeNegativeresistPositiveresist G-line i–line reverseimage TAC---topanti-reflectivecoating BARLI---bottomanti-reflectivecoatingChemicalamplificationresistXrayresist4.3.2 Exposure(曝光)

AlignerTechnology1. Contactprint(接觸） Softcontact,hardcontact,proximity2. Scanner(掃描）3. Stepper(重復(fù)） 1X,2X,4X,5X,10X4. Step–Scan(重復(fù)掃描) 4X---reticlemove,wafermove,reticle/wafermove5. Xray(X光）1:16. E-beam(電子束）---Directwrite4.3.3 Exposure(曝光)

Contactprint(接觸）1. Mostofusefornegativeresistprocess---for5uprocessandcanbepushto3u.2. Positiveresistcanprintsmallerthan3u,anddeepUVcanpushto1u,butveryhighdefect3. Equipment: ---CanonPLA501 ---Cobilt ---Kasper ---K&SContactprint---Canon501PE240ScannerCanon600Scanner4.3.5 Exposure(曝光)Stepper(重復(fù)）

1. Glinepositiveresist---for<0.8uprocess2. ilinepositiveresist---<0.5uprocess3. ilineresistplusphase-shiftmask---canbepushedto0.354. deepUVresistprocess---0.35uandbelow5. Equipment: ---Ultratech ---Canon ---Nikon ---ASML 4.4.1 Develop(顯影）Developprocess 1. Postexposebake 2. ResistDevelop 3. DIwaterrinse 4. HardBakeDevelopequipment 1. Batchdevelop 2. TrackdevelopDevelopchemical 1.

KOH 2. Metalfree(TMAH)--- Tetramethylamoniahydroxide 3. Wettingagent---with/without 4. Concentration---2.38%TMAHTrackdevelopmethod 1.

Spray 2. Steam 3. Signal-Paddle 4. Double-Paddle4.4.2Develop(顯影）DevelopTrack1. TemperaturecontrolwaterjacketforDevelopline2. Developpump/developpressurecanister3. Exhaust4. Hotplatetemperaturecontrol5. Pre-wet---processprogram4.4.3 Develop(顯影）CDcontrolindeveloping1. Postbakeprocess2. DevelopTime3. Concentrationofdeveloperchemical(Higherfast)4. Developertemperature(lowerfaster~1oC/0.1u)5. Developrecipe---pre-wet,paddle,rotation6. Ageofthedevelopchemical7. Rinse---DIwaterpressure8. Hardbaketemperature4.5.2 DevelopInspection

Inspectionitems1. Layername2. Alignment3. Runin/out4. Patterndistortion5. Patternintegrity6. Defects lifting,particle,discoloration,scumming,bridging,excessresist,scratch7. CD(criticaldimension)

Nanoline---forCDmeasurementHitachi8860---CDSEMLeitzMicroscopeinspectstationAutoloadUVinspectionsystem

5.0 BCD正膠工藝Equipment SSI,SVG8800,SVG90Processstep pre-bake/HMDS/coldplate spin(<5000rpm)---dynamicdispense ---top(bottom)sideEBR(2mm) softbake(100oC)/cold/palteResist/spec Shipley 6112(1.2u) 1818(1.8u1stmetal) 6818(2.4u2ndmetal) 6118(2.9uPad) 6124(3.6u-4.5uST) Everlight 533(1.2) Uniformity---+300AResistcoating升降機(jī)冷板HMDS涂膠熱板冷板升降機(jī)SVG90SVG88005.1.1 PositiveResist(正膠）Component(成分）Resin（樹(shù)脂） Diazonaphthoquinone(DNQ)/novolakPhoto-sensitizer（感光劑）Solvent（溶劑）Dye（染料）Manufacturing(制造商）Kodak–Hunt–Ashchemical(USA)TOK(Japan)JSR(Japan)Shipley(USA)AZ(USA,Germany)Sumitomo(Japan)Everlight(Taiwan)5.1.2 PositiveResist(正膠）ProductNameandfeature(產(chǎn)品稱與特性）以everlight(永光）正膠為例 ProductSeries EPG510Series Exposewavelength G-Line(435nm) Thickness Name 2000rpm5000rpm Viscosity（粘度） EPG510---12cp 1.25u 0.80u EPG512---21.5cp 2.00u 1.25u EPG516---50cp 3.25u 2.00u EPG518---105cp 4.50u 2.75u EPG519---460cp 9.00u 5.5u

Resolution(分辨率） 0.8u(0.55u---thesmallest) DepthofFocus(聚焦深度）+1.4u(1.0uline/space) Sensitivity(感光度） Eth=60mj/cm2

Eop=90mj/cm25.1.4 PositiveResist(正膠）Selectapositiveresist1. Resolution（分辨率）2. Resistthickness---Spincurve（厚度）3. Photospeed (曝光速度)4. Exposelatitude(曝光寬容度)5. Adhesion（粘附性）6. Reflectivenotch（反射缺口）6. Metalliccontent（金屬含量）7. Thermalstability（熱穩(wěn)定性）8. Plasmaresistance（抗腐蝕能力）9. Howeasytoberemoved（清除能力）10. Price（價(jià)格）5.2 ExposeEquipmentUltratechstepper1100–(6”)

Ultratechstepper1500–(6”)

Canon600 –(6”)

PerkinElmer240 –(4”)PositiveResistreactionduringexposePositiveResistreactionduringexpose5.2.1 UltratechStepper

UltratechstepperG-lineN/A---0.24and0.311:1printratio3X5inchreticle---3,4,5,7field4udepthoffocusBlindstepcanbepushto<5u(nospec)Centerofarray<+50uDarkfieldalignmentSitebySitealignmentAlignmenttarget *oat---4mmX4mm *K/T---200uX200uUltratechStepper1100UltratechStepper1500/17005.2.2 UltratchstepperspecificationUTS---ReticleandJobfileGuideFiducialsUTS---primarylensUTSAlignment

OpticUlratechsteppersitebysitealignmentUTalignmentprocedureLoadjobcomputerLoadreticleStartＦiducialsalignment---Guide,rotation(1500)OATalignment OATsize=4mmX4mm Fastandslowscan1000uSidebysidealignment Keyandtargetsize200uX200u shotscan20u longscan100u(80u)Auto-focus GobleorlocalFailurealignment Skip Expose Zmode5.3PerkinElmeralignerMicalignPE100MicalignPE200,220,240MicalignPE300,340,340HTMicalignPE500MicalignPE600MicalignPE700MicalignPE900Micscan100Micscan200Micscan300Micscan400PE240

SpecificationPE240PE240PMCenterofcurvatureParallelismLightintensityFocusDistortionMask/wafercenteringViewopticHPCrebuildCoolingairflowrateVibrationfromHPCFacilityVibrationfromenvironmentTemperaturecontrolhoodProcessReferencewaferApertureselectionResistbuilduponXYOpinsRoofmirrorcleaningMaskheatupduringexposePE---FocuswedgemaskPE---distortionPE---ProjectionopticPEMercurylampPE---AdjustableslitPEalignmentprocedureSetscanLoadmaskLoadwaferSwitchtomaskUsemicroscopeandcarriagemovementtofindthealignmentmarkonmask(Testdie)MovemaskonlytoalignthewaferSwitchtowaferMovewaferaligntomask5.4.1 ResistdevelopEquipment SSI,SVG8800,SVG90Processstep pose-ebake/coldplate develop---doublepaddle ---DIwaterrinse ---backN2/rinse hardbake(110-130oC)/cold/palteDeveloper TMAH2.35%

升降機(jī)冷板熱板冷板升降機(jī)熱板顯影SVG8800SVG905.4.2ResistdevelopEquipment DevelopsinkEquipmentsetup Temperature N2blanket Filtersize Filterchange

Developer TMAH2.38% DevelopchangeProcessstep batchdevelop---immerse(1’&15”) QDRDIwaterrinse(8cycles) hardbake(110-130oC)/cold/palte6.Historyand未來(lái)的光刻工藝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.6.1 History

Lithography,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.6.2Future

IntroductionofnanoimprinttechnologyFabricatingmicrostructuresandnanostructureisimportantinmanyfieldsofscienceandtechnology,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.Theimprintmethodsutilizeheato