IC工艺技术3-刻蚀课件

IC工艺技术系列讲座

第三讲ETCHING刻蚀IC工艺技术系列讲座

第三讲ETCHING1讲座提要1. General 1.1 Isotropic/Anisotropicetch(无定向/定向刻蚀) 1.2 Facility(动力环境)2. Wetetch 2.1 Wetetchmechanism（湿化刻蚀机理） 2.2 BOEetch（氧化硅刻蚀) 2.3 Aluminumetch(铝刻蚀) 2.4 Nitrideetch(氮化硅刻蚀) 2.5 Poly/siliconetch(多晶硅/单晶硅刻蚀) 2.6 DIwaterrinseanddry3. Dryetch 3.1 PlasmaTheoryandapplication(等离子理论和应用) 3.2 Typeofplasmaetch(等离子刻蚀种类) 3.3 Etchinggasesandpressure(刻蚀气体和低压） 3.4 Etchprocesshighlight(刻蚀工艺简介) 3.5 Etchprocessparameter(刻蚀工艺参数) 3.6 Ionmilling(离子铣) 3.7 BCDplasmaetchingequipmentandapplication5. Nextetchprocess未来的刻蚀工艺讲座提要1. General21.1GeneralIsotropicetch(无定向刻蚀)Etchinghasnodirection.Wetetchoraplasmaetchwithoutsidewallpassivationprocess.Itcausesundercutduringtheetchingandchangecriticaldimension.Anisotropicetch(定向刻蚀)EtchwithdirectionorsidewallprotectionIonmilling,RIEortheplasmaetchwithenoughsidewallpassivationprocess.Afteretch,criticaldimensionhasnochangeorveryslightlydifference.1.1GeneralIsotropicetch(无3Isotropicetch(无定向刻蚀)Anisotropicetch(定向刻蚀)ResistIsotropicetch(无定向刻蚀)Anisot41.2 FacilityDIwater(去离子水)17mhomDrain(排水)SpecialchemicaldisposesystemExhaust(排风)CompressairandNitrogen(加压空气,氮气)Inhousevacuum(真空管道)Coolingwater(冷却水)Gascabinet/Gasline(气柜,气体管道)Gasbottle(气瓶)1.2 FacilityDIwater(去离子水)152.0 Wetetch

AdvantageanddisadvantageChemicaletch(化学刻蚀）---isotropyCDloss（线宽变小）Highparticlecontamination（高颗粒）Unableforsmallgeometry(不能用于小尺寸工艺)Higherprocesscost（工艺费用高）Mostofwetetchprocesshavehighselectivitytotheunderlayer（高选择比）Fastthroughput（产量高）Lowequipment(investment)cost（投资少）2.0 Wetetch Advantageand62.1.1 Wetetchmechanism（湿化刻蚀机理）WafersurfacewettingandcontactwithetchchemicalChemicalreactiontakesplace,solublebyproductformation.Removebyproductfromwafersurface

Theetchrate(anduniformity)affectsbyTemperatureThesloweststepofoneofabovestep2.1.1 Wetetchmechanism（湿化刻蚀72.1.2 Wetetchbyproduct(副产物)Partofbyproductwillbeconvertedtowatersolublematerial.(水溶性)Partofbyproductwillconvertedtogasform. Ifthegascannotberemovedfromthewafersurfacesoonenough,theproblemwilloccur * Blocketch---snow(雪花) * Hidingatedgeofresist---lifting(浮胶)2.1.2 Wetetchbyproduct(副产物)82.1.3WetetchimprovementImprovementmethodPre-wet---wettingagent（湿润剂）Agitation（搅动）Circulation（循环）Temperaturecontrol（温度控制）Filtration（过滤）Inavacuum（真空）Sprayetch（喷洒）Vaporetch（蒸发）Selectionofhighpurityofchemical（选择高纯度化学药品）2.1.3Wetetchimprovement92.2.1BOEetch

BOE(Bufferoxideetch) mixedwithHFandNH4FChemicalreaction

SiO2+6HF H2SiF6+2H2O

NH4FNH3+HFNH4F(bufferagent–缓冲剂) keepaconstantHFconcentrationduringreaction

NH3---controlPHvalue

2.2.1BOEetchBOE(Buffer10CDlostinBOEetch（氧化硅刻蚀)

CDlostinBOEetch（氧化硅刻蚀)11BOEetchsink（氧化层刻蚀水槽)

BOEetchsink（氧化层刻蚀水槽)122.3Nitrideetch（氮化硅腐蚀）Phosphoricacid(磷酸）---H3PO4Heatupto140to200oCConstantwatercontain（稳定水含量）Etchrate~50A/minat165oCSelectivitytooxide~10:1Selectivitytoundopedsilicon>30:1SelectivitytoN-siliconismuchpoorer(higherdopingfasteretchrate)2.3Nitrideetch（氮化硅腐蚀）Phosph132.4 AluminumEtch(铝刻蚀)Chemical Phosphoricacid 77% Aceticacid 20% Nitricacid 3%EtchTemperature 30to70oC(keepetchtimefrom3to5min)Etchtime Manual/autoendpointEtchrateaffect Temperature AmountofNitricacidByproduct AluminumAcid-ate HydrogenEquipment Manualetchbath Automaticetchsink Waterflowetch(Watanabe) Vacuumetcher Sprayetcher(Dinippon)2.4 AluminumEtch(铝刻蚀)Chemi14FewspecialissuesinAluminumEtchSnow--- TherearealotofH2arereleasedduring etching.Inthehighviscosityacid,theH2 bubbleiseasilytoattachonthewafersurface butcannotfloattothesurface.Itblocksthe etching. *Agitation---mechanical *Waterflow---mechanical *Spray---mechanical *Vacuum---reducesurfacetensionResidue--- Whenetchaluminumalloyfilm,thesiliconis unabletobeetchedintheacid.Itwillleaveon wafer. *Defeckleetch---mayattackaluminum *Plasmaetch---residueisdifficulttobeetch indenseareaFewspecialissuesinAluminum152.5Poly/siliconetch(硅刻蚀）Chemical 1.HNO3+

HF(8:1) 2.KOHsolution(forsignalcrystalsilicon)Polyetch Polyneedoxidemask DilutetheHF/HNO3withaceticacidorDIH2O

Siliconetch HF/HNO3etchwithnodirection KOHetchwithdirection---alongcrystalline2.5Poly/siliconetch(硅刻蚀）Ch16WetetchtableWetetchtable17DIwaterrinseequipmentCascade---Slow,initialbathcontainweakchemicalQDR(QuickDumpRinser) Fast,CreateESD(particle),Cycletime,numberofcycleSprayrinse---Runwithdryer*HotDIwaterisincreasingtherinseefficiency2.5DIwaterrinseanddryDIwaterrinseequipment2.518Waferdry Mechanicaldry---

(particle,residue)Multiplecassettesspindry FSISinglecassettespindry Semitool

ChemicalDryFreonvaporHotwater/airdry AlcoholvapordryAlcoholdry

Waferdry Mechanicaldry---(193.0Dryetch（干化刻蚀）AdvantageanddisadvantageAnisotropyetch(定向刻蚀)CDlossundercontrol（线宽可控制）Etchsmallgeometry（小尺寸刻蚀）Simpleprocess(dryin–dryout)（简单程序）Lowprocesscost（低成本工艺）Plasmadamage（刻蚀损害)Lowselectivity（低选择比）Lowerthroughput（产量低）Highequipmentcost（投资高）3.0Dryetch（干化刻蚀）Advantag203.1 PlasmaTheoryandapplication

(等离子理论和应用)Definitionofaplasmaisapartiallyionizedgasthatiselectricallyconductive.Plasmaenergycanbeusedtoactivatechemicalreactionsandtoetchordeposituponsurfacesexposedtotheplasma3.1 PlasmaTheoryandapplicat21Often,electricalpoweriscoupledintoaplasmabymeansofparallelmetalelectrodesTheaccelerationofelectronsistheprincipalmeansbywhichenergyiscoupledintotheplasma.TheamountofenergygainedbyaelectronisequaltotheforceonittimesthedistanceOften,electricalpoweriscou22IC工艺技术3--刻蚀课件23Plasmadensity

Inaplasma,wehaveseenthatnewfreeelectronsaregeneratedbyelectron-impactionizationgasatomsandmolecules.Atthesametime,manyofelectronlosttotheelectrodeandothersurroundingsurface.Sotheplasmastabilizeatadensityofelectronsforwhichthegenerationrateisbalancedbythelossrate. Thisstabilizedelectronleveliscalledtheplasmadensity.Plasmadensity24Foragivenreactor,plasmadensityisdeterminedbyfourprincipleinputs:1. Thevoltageappliedtotheelectrode Higherappliedvoltageleadstomoreelectronenergygainbetweencollisions2. Thegascomposition Themoleculethathasweakermoleculebondiseasierigniteplasma3. Thegaspressure Gaspressureaffectsplasmadensitythroughthecollisionrate.Inhigherpressure–shortermeanfreepath.Atlowvoltage,toomuchenergylostinnon-ionizingcollisionandplasmadiesout.Athighvoltage,oneelectroninitialssomanyionizingcollisionsthatanexcessivelyconductpathiscreatethroughtheplasma,itcausearcing.Toolowpressure,gascrosstheelectrodegapbeforetheygenerateenoughionizingcollisions.4. Theapplicationofamagneticfield Amagneticfieldcanbesetupacrossaplasmareactorusingexternalmagnets.Electronattemptingtocrossthemagnetizedplasmawillhaveamuchlongerpathlengthinwhichtoencountercollisionwithgasmoleculesbeforetheyarelosttotheelectrode.Thismeansthatthepressurecanbemuchlowerbeforethecollisionratebecomesinsufficienttosustaintheplasma.Foragivenreactor,plasmade25InhighpressureplasmaAddedamagneticfieldInhighpressureplasmaAdded26Etchtheory---ionbombardment Theelectronaremuchlessmassivethantheions,sotheymovemuchmorerapidly.Theresultinadepletionofelectrodeofelectronsfromthespaceabovethecathode.Theionslefthereconstituteapositivespacecharge.Theregionofpositivespacechargeiscalcathodesheath.Constrictingthevoltagedropinthiswayincreasetheforceontheionsinthesheathandcausethemtobeacceleratedintocathodewheretheyarrivewithconsiderableenergy~500electron-voltsEtchtheory---ionbombardmen27Etchtheory---ionbombardmenteffectElectronemission--- emissionthesecondaryelectrons thathelpsustainthedirect-current plasma.Chemicalactivation--- Chemicalreactiveandphysical bombardmentMomentumtransfer--- Nochemicalreaction,move surfaceatomtoremoveofimpurity atomsbyevaporationEtchtheory---ionbombardmen28ACplasma

TheaboveDCplasmatheoryistobeusedtoillustrateabasicofplasma.TheACplasmaisusedinrealtime.ThecathodeandtheanodeisalternatinginaACpowersource.ThefrequencyoftheACpowerisselectedtobeusedinthisindustry.Thelowestfrequencytomaintainaplasmais100KHz13.56MHzRF(radiofrequency)ismainlyusedinsemiconductorfieldWaferthatsitsonpowerplatereceivesmorebombardmentWaferthatsitsongroundplatehaslessplasmadamageACplasma TheaboveDCplasma29Plasmaetchmechanism(等离子刻蚀机理)

Thepositiveionaredrawntothecathode,andthenegativeionstoanode.Inamediumpressurediodereactor,only1in50,000ofthegasmoleculesareionized.Therefore,ionsarenotthemaindriversintheetchprocess,althoughtheyplayamajorrole. Becausefreeradicalsareneutral,theybehavemuchlikestandardgasmolecules.Whenagasmoleculefragmentsintheplasma,eachfreeradicalformedtakesupasmuchspaceastheoriginalmolecule.(Thisiswhythepressurejumpswhenaplasmaignites)Theyaremorereactivethantheywereintheiroriginalform,andareimportantetchratedrivers.Freeradicalsareverylong-livedinavacuumenvironment.Plasmaetchmechanism(等离子刻30Plasmaetchmechanism(等离子刻蚀机理)Plasmaetchmechanism31PlasmaetchmechanismPlasmaetchmechanism32CF4etchChemicalreaction(CF4刻蚀化学反应)CF4etchChemicalreaction(33Plasmaetchmechanism(等离子刻蚀机理))Plasmaetchmechanism(等离子刻34Plasmaetchmechanism(等离子刻蚀机理)FewnotesinCF4plasmaetch

Theplasmacontainsenergeticionswhichbombardthewafersurface,aswellasothersurfaceinthereactorchamber.Theyareacceleratedacrossthevoltagedropregionatthesurface,andcollidewithitathighspeed..Thisionbombardmentisalsocausesanodizationwear. Duringthesiliconetch,themostprevalentchemicalreactionproceedsasfollows: 4F*+Si---SiF4 AstheSiF4gasforms,itispumpedaway.Thebi-product(CFpolymer)depositsonthewaferaswellasinthechamber.Onlythepolymeronwafersurfacethatreceivebombardmentwillberemoved.Theetchprocesscontinuesaslongasthedepositionrateofthepolymerdosenotexceeditsetchrateduetoionbombardmentandgasreaction.Whenetchhitstheunderlayer,SiF4formationdecrease.ThelightemissionfromtheSiinplasmadecrease.TheetchingcanbesignedtoreachendpointPlasmaetchmechanism(等离子刻353.2 Typeofplasmaetch

(等离子刻蚀种类)

Operating Frequency Pressure EquipmentBarrel 13.56MHz 500mt IPCDownstream 2.45GHz 2torr GasonicA1000Parallelplate 13.56MHz 300mt Lamautoetch, Rainbow4400,4600,4700 Tegal700,800,900Triode 13.56MHz(T) 300mt Tegal1500,1600 100KHz(B) Drytek384TSPRP 400KHz 200mt LamRainbow4500MERIE 13.65MHz 100mt Precision5000RIE 13.56MH 20mt AME8000TCP 13.56MHz(P) 1-5mt Lam 13.56MHz(B)DPS 13.56MHz(P) 1-5mt Centrura 13.56MHz(BMRE 13.56MHz(T) 3mt Tegal6000 800KHz(B)ECR 2.45GHz(T) 0.5-5mt Hitachi 13.56MHz(B)Helicon 0.5-5mt 3.2 Typeofplasmaetch(等离子刻36IPCbarreletcher13.56MHzUseoxygenonlyforresistashingat1torr/500wUseCF4/O2foretchingat0.5torr/250wIPCbarreletcher13.56MHz37Tegal900seriesParallelplateetcherTegal900seriesParallelplate38Lamautoetch490/590ParallelplateetcherLamautoetch490/590Parallelp39Tegal1500/1600seriesTriode-dualfrequencyetcherTegal1500/1600seriesTriode-40AME8300SeriesAME8100seriesisthemanuallywaferloadingsystemAME8300seriesistheautomaticallywaferloadingsystem

AME8310---Oxideetcher AME8330---metaletcher AME8340---polyetcherAME8300SeriesAME8100series41LamRainbowetcherRainbowisthenameofLametchplatform4400isapolyetcherusedRFpower,wafersitsonground.4500isanoxideetcherusedSPRPpowersource4600isametaletcher,wafersitsonpowerelectrode.LamRainbowetcherRainbowist42ECRECR43Gasonic1000UsemicrowavepowerfordisassociateGasGasonic1000Usemicrowavepowe44Trendsinplasmaetchchemistry1MaterialbeingetchedConventionalchemistryNewchemistryBenefitsPolysiliconCL2or/CCL4BCL3/CF4/CHCL3/CHF3/sidewallpassivatinggasesSiCL4/CL2BCL3/CL2HBr/CL2/O2HBr/O2Br2/SF6SF6/25%O2Nocarboncontaminationincreasedselectivitytooxide&resistnocarboncontaminationhighetchratePolycidesCL2+HBrtoclearSinglecrystalSiCL2orBCL3+sidewallpassivatinggasesCF3BrHBr/NF3HICL2/ArHighselectivity-trenchHighselectivity-100:1trenchAlCL2+sidewallBL3passivatinggasesSiCL4SiCL3/CL2BCL3/CL2HBr/CL2BetterprofilecontrolNocarboncontaminationAl-Si(1%)-Cu(0.5%)SameasAlBCL3/CL2+N2N2acceleratesCuetchrate3.3 Etchinggasesandpressure

(腐蚀气体和低压）Trendsinplasmaetchchemistr45Trendsinplasmaetchchemistry2MaterialbeingetchedConventionalchemistryNewchemistryBenefitsAl-Cu(2%)BCL3/CL2/CHF3BCL3/CL2+N2+AlAdditionalAlhelpsetchCuWSF6/CL2/CCL4SF6/ArNF3/CL2CL2/O2EtchstopoverTiWandTiNTiWSF6/CL2/O2SF6+ArorN2TiNAr/CL2WSi2,TiSi2,CoSi2CCL2F2CCL2F2/NF3ControlledetchprofileNocarboncontaminationSiO2(BPSG)&(PSG)CCL2F2CF4C2F6C3F8CCL2F2CHF3/CF4CHF3/O2CH3CHF2CFCalternativesPSGonTiSi210:1Si3N4CCL2F2CF4/O2CF4/H2CHF3CH3CHF2CFCalternatives3.3 Etchinggasesandpressure

(腐蚀气体和低压）Trendsinplasmaetchchemistr463.3 Etchinggasesandpressure

(腐蚀气体和低压）

Pumpsusedinsemiconductorprocess AppliedPressure VacuumRangeMechanicpump 10-2 760-10-3 机械泵Mechanicpump/blower 10-2 760-10-3 机械泵+罗茨泵Diffusionpump 10-5 10-3-10-7 扩散泵Turbomoleculepump 10-5 10-2-10-10 分子泵(50000rpm)Cryopump 10-7 10-6-10-12 冷泵3.3 Etchinggasesandpressur473.3 Etchinggasesandpressure

(腐蚀气体和低压）Pumpsusedinetchprocess

DrypumpstackTurbopumpOilpumpOilpumpStack3.3 Etchinggasesandpressur483.4 Etchprocesshighlight

(腐蚀工艺简介)PolysiliconetchNitrideetchOxideetchAluminum/aluminumalloyetchPolycidesetchSOGetchW/TiW/TiNetchResistetch(ash)Typeofetchprocess3.4 Etchprocesshighlight(腐蚀49Polysilicon&salicidesEtch

PolysiliconcanbeetchedbyCF4,SF6orCl2chemistryinaparallelplateetcher,butonlytheCl2processisananisotropicprocess.

Herearesomemoreadvancepolysiliconetchrecipesandsaliciderecipes:

1.CL2withECRuwaveplasma,875gauss, etchrateincreaseswithCL2flow,etchingby neutrals,lowerstheflowrate,increasesions andincreasesanisotropicprofile; 2.MERIEofsilicideoverpolysilicon(salicide) ongateoxide;CL2at-80Vd.c.biasfor silicide,reduced.c.biasandpowerdensity forpolyetchtoendpoint,switchtoHBrto clearwindowsofstringers,etc.Polysilicon&salicidesEtch 50Silicondioxideanddopedglasses-sidewallspaceretching Useasinglewafersystem,thetypicaletchchemistryisCHF3/C2F6(CF4)/He.Itremovesbulkofoxideintimedcycle,reduceC2F6(CF4)flowpower,increaseselectivitytopolyto11:1toendpoint.Reducetemperatureonwaferelectrodewillincreaseselectivity. TCP,NF3+He,improvedselectivityoxidetopolyof60:1to100:1,--600nm/minforBPSG.Silicondioxideanddopedglas51Aluminumalloysandsandwichmetalsystems ChlorinebasedcompoundsetchAlandAl+Sireadily.Theadditionofcopperisaproblem,becausethevolatilityofCuClxisverylow.Mostmetaletchingisdonebyion-enhancedprotectivewithBCL3+CL2+CHF3,followedbypostetchtreatmentinafluorine-richplasmatoexchangetheadsorbClwithnon-corrosiveF.TheadditionofN2andAlincreasestheetchrateofCu.Aluminumalloysandsandwichm52Photoresist

Oxygenplasmaareastandardmethodforstrippingphotoresistbyashing.Damagecanoccurduringthisrelativelyuncontrolledoperation.Widelyacceptedarethemetalatomsandioniccontaminationpresentintheresist,whicharenotremovedintheplasma.Acombinationofdryandwetstrippingispreferred.Photoresist Oxygenplasmaare533.4 Etchprocesshighlight

(腐蚀工艺简介)Breakthrough Removenaïveoxide---lowerselectivityBulketch(Mainetch) Highetchrate,maximizedselectivity, optimumselectivityOveretch Goodendpointsignal,highselectivityto under-layermaterial* ResistremovalPartiallyorcompletelyremoveresistThemajoretchsteps3.4 Etchprocesshighlight(腐蚀543.5 Etchprocessparameter

(刻蚀工艺参数)Etchrate(everysteps)(刻蚀率）etchuniformity(everysteps)(刻蚀均匀度）Selectivity(tobottomlayermaterial/ resist/impurityinfilm)(选择比）Endpointdetection(终点检测）Loadingeffect（负载效应）Residue（残余）Damage（损伤）Throughput（产量）3.5 Etchprocessparameter(刻55Forward/reflectivepowerBasepressureLeakratePartialpressure(gasflowandpumpspeed)MFCcalibrationWafertransferreliabilityWafertransfercycletimePumpmaintenance* TheusefulparameterdataistakenfromanequipmentthathasbeenproveditsperformancesareinspecificationPreventiveMaintenanceForward/reflectivepower* T56EtchRateUniformitySelectivityEtchRateUniformi57TypeofEndpointdetectionTypeof endpointdetection EquipmentLaser Dryteck,AME8110Emissionspectroscopy MostofdryetherInfra-red VacuumetcherBrightlightreflection SprayaluminumwetetchTypeofEndpointdetectionTyp58EmissionspectroscopyEndpointdetectionInaplasma,excitedatomsandmoleculesemitlightspectrumwhentheirelectronschangeenergystates.Thestrengthoftheemittedlightspectrumindicatetheprogressionandcharacterizationofthechemicalandatomicreaction.EmissionspectroscopystudythespecificlightspectrumanddetectiontheendofaspecialreactionLam590EndpointtraceEmissionspectroscopyEndpoint59TypicalwavelengthsinEPapplicationOxide CO: 482.5nmor520nm SiF: 440nmPoly SiCl2 405nm F 704nmNitride SiN 405nmAluminum AlCl 261.4nm,527nm Al 396nmResist CO 297.7nm,483.5nm520nmSilicon SiCl2 405nmTypicalwavelengthsinEPappl60Loadingeffect

Theloadingeffectisthephenomenonthatetchingunevenlocally.Thisphenomenonisnewandspecialtotheplasmaetchprocesses.Theetchratecanbebeststatedbythisequation: Plasmaetchrate = 1____ exposedsurfaceareaLoadingeffectismoreseveretobehappened * onthechemicalbehaveetchingplasmaprocess. * ontheetchprocessthatreliesonsidewallpassivation. *Waferwithunevenresistpatterndensity. *WaferwithvarioussizeofopeningLoadingeffect Theloadingef61PolyResidue1. Causebyunderetch2. Impurityinthefilm---POCL3contaminationinpoly3. Contaminationinunderlayerfilm4. PolymerleftoverPolyfilmetchedtoendpointinLam490PolyResidue1. Causebyunder62DamageSomeoftheproblemsassociatedwithanisotropicRIEarelistedasfollow:MetallicContamination-Deepleveltraps;Degradedlifetimes;Highcontactresistance;LeakagecurrentPolymerFormation-HighcontactresistanceUVRadiation-TrapgenerationElectroStaticDischarge(ESD)-GateoxidebreakdownPhysicalDamage-DuetoenergeticionbombardmentTheetchingprocessisdirectional;therefore,foreignmaterialonthesurfacecanalsoactasamask,changingthedesiredetchedpattern.Heavymetals(forexample,knockedoffchamberwallsortheelectrodebyionbombardment)maycontaminatethewafers.RadiationdamagecanoccurinthesilicondioxidebythebuildupoftrappedchargeintheoxidelayerDamageSomeoftheproblemsass633.6Ionmilling(离子铣) Ionbeammillingusestheenergyimpartedtoabeamofions.Theionbeamusuallyconsistsofanionizedinertgassuchasargontoperformetching.Theionswithenergiesinthe300-1500eVrangestrikethebondsthatholdthemtoadjacentatoms.Thisprocessdependsonimpactandenergytransfer,notonthechargeoftheincomingion.Thechargeoneachionintheincidentbeammakestheformationofacollimated,singleenergybeampossible.TheschematicofatypicalionmillingsystemisshowninFigure6.3.6Ionmilling(离子铣) Ionbe643.7BCDplasmaetchingequipmentand applicationLam490 Diode Poly,NitrideLam590 Diode OxideAME8330 RIE Metal,MetalalloyAME8310 RIE OxideTegal1611 Triode Poly,NitrideTegal1612 Triode Metal,MetalalloyTegal903 Diode Oxide(4”)GasonicA100 Microwave Resist,DescumTegal915 Diode Resist,DescumIPC Capacitive Resist,Descum3.7BCDplasmaetchingequipm65BCDPolyetchLam490Parallelplateplasmaetcher13.56MHzLoad-lockUserecipemoduleDualendpointchannel(405nm)BelttransferAnodizedaluminumelectrodeCassettetocassetteChlorinechemistryUpgradeHBr---Improveoxide selectivityEtchrate3700-4100(undopepoly)Uniformity<5%Selectivitytooxide40:1SelectivitytoPR2:1BCDPolyetchLam49066Lam490PolyetchloadingeffectinCl2chemistryprocess---improvebyaddingHBr490Cl2process1%resistpattern50%resistpattern1611HBrprocessLam490Polyetchloadingeffe67BCDNitrideetchLam490Parallelplateplasmaetcher13.56MHzLoad-lockUserecipemoduleDualendpointchannel(405)BelttransferAnodizedaluminumelectrodeCassettetocassetteSF6andSF6/O2mixedchemistryUpgradeHBr---Improveoxide selectivityEtchrate1600A(LPCVD)Uniformity<5%Selectivitytooxide3:1SelectivitytoPR>2:1BCDNitrideetchLam49068BCDOxideetchLam590Parallelplateplasmaetcher13.56MHzLoad-lockUserecipemoduleDualendpointchannel(520)BelttransferGraphiteupperelectrodeCassettetocassetteCHF3/CF4mixedchemistryEtchrate3700-4100Uniformity<5%Selectivitytopoly3:1SelectivitytoPR3:1BCDOxideetchLam59069590oxideetchissuesConsumptionofGraphitecausesloweretchrateandreducingetchuniformityInconsistentcontactresistanceMetalstepcoveragedifficultcausebyhigheraspectratioHighpowerdensityplasmahashigherarcingpotentialPolymerformsinthechamber onthechuckneartheedgeofthewafer,endpointviewspot.590oxideetchissuesConsumpti70AluminumalloyetchAME8330RIEetcher13.56MHz1800Wat<50mtorrWallmountingLoad-lockCassettetocassetteUnlimitrecipescapacity4endpointchannel(AlCl396nm)HexagonelectrodeBCl3/Cl2chemistryUpgradeHBr---ImprovePR selectivityEtchrate400(undopepoly)Uniformity<5%Selectivitytooxide4:1SelectivitytoPR1:1AluminumalloyetchAME833071AME8330etchissue11. EtchselectivitytoresistIsverypoorinAME8330duestrongionbombardmentReducepowergascombination(AddingHBr)Hardmask(nitride,SOG…)DeepUVtreatmentbeforeetch2. Etchuniformity Processadjustment,putindummyslotFusion150AME8330etchissue11. Etchs72AME8330etchissue2ResidueReducebulkEtchselectivityReduceBulketchrateIncomealuminumfilmQualityExtentoveretchAME8330etchissue2Residue73AME8330etchissue3

Aluminumalloyfilmsurfacehasholesafterresist/polymerareremoved,thisGalvanicCorrosioncausesinchemicaltreatmentprocess.ThischemicalcontainsAminebasechemistryor/andHydroylamimeinNMPtoacceleratealuminumetchingaroundthecuppernodule.KeepAlgrainsizesmalltominimizeCumigrationbyoptimizingmetaldeposition,minimizingthermalcyclesafterdepositionImmediaterinse(Alcohol…)QuickagitateinDIwaterrinse,andaddingCO2forneutralizationAddARConmetalAME8330etchissue3 Aluminu74AME8330etchissue4Photosweretakenafterresistremoved

MicroscopeSEMCorrosionremovedAME8330etchissue4Photoswe75AME8330etchissue4IncreaselastpumpdownFpassivation(ionexchange)CompletelyresistremovalRinseimmediatelyAME8330etchissue4Increase76ResistashGasonicA1000HighlampturnontimeImplantresistOverashingTemperatureonwaferIPCFinaltemperatureChambertemperaturefordescumQuartzchamberfrostyUniformityfronttoendResistashGasonicA1000IPC775. 未来的刻蚀工艺Polysilicon/PolycideThinnerpolysiliconwillbeused(1500-2000A),therefore,loweretchratecanbetolerated.Undopedpolysiliconwillbeused,theprofilecontrolwillnotbeaissue.(afterpolylineformed,N+dopedforNchannel,andP+dopedforPchannel)Stoponoxintrideorotherexoctichighdielectricconstantmaterialselectivitywillnotbeaissue.(HBreasilyobtaina100:1selectivity.5. 未来的刻蚀工艺Polysilicon/Polycide78OxideHighdensity,lowpressureplasmawillbedormantforthisapplicationEtchstoponSiNwillbeusedforimprovingselectivityC4H8/CO2etchingchemistrywillbeusedextensivelyforSAC(selfaligncontact)andtrenchstructureNeedlowetchrateandlowdamageplasmaforlowKandporousmaterialetch.5. 未来的刻蚀工艺Oxide5. 未来的刻蚀工艺79MetalCupperwillbeusedfornarrowlinetoreplacealuminumalloymaterialUsecupperastheconnectorcannotbeusedtheconventionaletchingprocess,thenewprocessscheme: * etchoxidetrench * sputterseedlayer(TaN) * cupperplating * CMPstoponTaN * etchTaNAluminumalloyfilmforuppermetalonly(thickandwidestructureetching)5. 未来的刻蚀工艺Metal5. 未来的刻蚀工艺80ChemicalMechanicalPolish化学机械抛光 The1stCPMequipmentstartedinproductionsince1990.Nowmostofsubmicronsemiconductorfa