IC工藝技術(shù)3-刻蝕課件

IC工藝技術(shù)系列講座

第三講ETCHING刻蝕IC工藝技術(shù)系列講座

第三講ETCHING1講座提要1. General 1.1 Isotropic/Anisotropicetch(無(wú)定向/定向刻蝕) 1.2 Facility(動(dòng)力環(huán)境)2. Wetetch 2.1 Wetetchmechanism（濕化刻蝕機(jī)理） 2.2 BOEetch（氧化硅刻蝕) 2.3 Aluminumetch(鋁刻蝕) 2.4 Nitrideetch(氮化硅刻蝕) 2.5 Poly/siliconetch(多晶硅/單晶硅刻蝕) 2.6 DIwaterrinseanddry3. Dryetch 3.1 PlasmaTheoryandapplication(等離子理論和應(yīng)用) 3.2 Typeofplasmaetch(等離子刻蝕種類(lèi)) 3.3 Etchinggasesandpressure(刻蝕氣體和低壓） 3.4 Etchprocesshighlight(刻蝕工藝簡(jiǎn)介) 3.5 Etchprocessparameter(刻蝕工藝參數(shù)) 3.6 Ionmilling(離子銑) 3.7 BCDplasmaetchingequipmentandapplication5. Nextetchprocess未來(lái)的刻蝕工藝講座提要1. General21.1GeneralIsotropicetch(無(wú)定向刻蝕)Etchinghasnodirection.Wetetchoraplasmaetchwithoutsidewallpassivationprocess.Itcausesundercutduringtheetchingandchangecriticaldimension.Anisotropicetch(定向刻蝕)EtchwithdirectionorsidewallprotectionIonmilling,RIEortheplasmaetchwithenoughsidewallpassivationprocess.Afteretch,criticaldimensionhasnochangeorveryslightlydifference.1.1GeneralIsotropicetch(無(wú)3Isotropicetch(無(wú)定向刻蝕)Anisotropicetch(定向刻蝕)ResistIsotropicetch(無(wú)定向刻蝕)Anisot41.2 FacilityDIwater(去離子水)17mhomDrain(排水)SpecialchemicaldisposesystemExhaust(排風(fēng))CompressairandNitrogen(加壓空氣,氮?dú)?Inhousevacuum(真空管道)Coolingwater(冷卻水)Gascabinet/Gasline(氣柜,氣體管道)Gasbottle(氣瓶)1.2 FacilityDIwater(去離子水)152.0 Wetetch

AdvantageanddisadvantageChemicaletch(化學(xué)刻蝕）---isotropyCDloss（線寬變小）Highparticlecontamination（高顆粒）Unableforsmallgeometry(不能用于小尺寸工藝)Higherprocesscost（工藝費(fèi)用高）Mostofwetetchprocesshavehighselectivitytotheunderlayer（高選擇比）Fastthroughput（產(chǎn)量高）Lowequipment(investment)cost（投資少）2.0 Wetetch Advantageand62.1.1 Wetetchmechanism（濕化刻蝕機(jī)理）WafersurfacewettingandcontactwithetchchemicalChemicalreactiontakesplace,solublebyproductformation.Removebyproductfromwafersurface

Theetchrate(anduniformity)affectsbyTemperatureThesloweststepofoneofabovestep2.1.1 Wetetchmechanism（濕化刻蝕72.1.2 Wetetchbyproduct(副產(chǎn)物)Partofbyproductwillbeconvertedtowatersolublematerial.(水溶性)Partofbyproductwillconvertedtogasform. Ifthegascannotberemovedfromthewafersurfacesoonenough,theproblemwilloccur * Blocketch---snow(雪花) * Hidingatedgeofresist---lifting(浮膠)2.1.2 Wetetchbyproduct(副產(chǎn)物)82.1.3WetetchimprovementImprovementmethodPre-wet---wettingagent（濕潤(rùn)劑）Agitation（攪動(dòng)）Circulation（循環(huán)）Temperaturecontrol（溫度控制）Filtration（過(guò)濾）Inavacuum（真空）Sprayetch（噴灑）Vaporetch（蒸發(fā)）Selectionofhighpurityofchemical（選擇高純度化學(xué)藥品）2.1.3Wetetchimprovement92.2.1BOEetch

BOE(Bufferoxideetch) mixedwithHFandNH4FChemicalreaction

SiO2+6HF H2SiF6+2H2O

NH4FNH3+HFNH4F(bufferagent–緩沖劑) keepaconstantHFconcentrationduringreaction

NH3---controlPHvalue

2.2.1BOEetchBOE(Buffer10CDlostinBOEetch（氧化硅刻蝕)

CDlostinBOEetch（氧化硅刻蝕)11BOEetchsink（氧化層刻蝕水槽)

BOEetchsink（氧化層刻蝕水槽)122.3Nitrideetch（氮化硅腐蝕）Phosphoricacid(磷酸）---H3PO4Heatupto140to200oCConstantwatercontain（穩(wěn)定水含量）Etchrate~50A/minat165oCSelectivitytooxide~10:1Selectivitytoundopedsilicon>30:1SelectivitytoN-siliconismuchpoorer(higherdopingfasteretchrate)2.3Nitrideetch（氮化硅腐蝕）Phosph132.4 AluminumEtch(鋁刻蝕)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(鋁刻蝕)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(硅刻蝕）Chemical 1.HNO3+

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

Siliconetch HF/HNO3etchwithnodirection KOHetchwithdirection---alongcrystalline2.5Poly/siliconetch(硅刻蝕）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（干化刻蝕）AdvantageanddisadvantageAnisotropyetch(定向刻蝕)CDlossundercontrol（線寬可控制）Etchsmallgeometry（小尺寸刻蝕）Simpleprocess(dryin–dryout)（簡(jiǎn)單程序）Lowprocesscost（低成本工藝）Plasmadamage（刻蝕損害)Lowselectivity（低選擇比）Lowerthroughput（產(chǎn)量低）Highequipmentcost（投資高）3.0Dryetch（干化刻蝕）Advantag203.1 PlasmaTheoryandapplication

(等離子理論和應(yīng)用)Definitionofaplasmaisapartiallyionizedgasthatiselectricallyconductive.Plasmaenergycanbeusedtoactivatechemicalreactionsandtoetchordeposituponsurfacesexposedtotheplasma3.1 PlasmaTheoryandapplicat21Often,electricalpoweriscoupledintoaplasmabymeansofparallelmetalelectrodesTheaccelerationofelectronsistheprincipalmeansbywhichenergyiscoupledintotheplasma.TheamountofenergygainedbyaelectronisequaltotheforceonittimesthedistanceOften,electricalpoweriscou22IC工藝技術(shù)3--刻蝕課件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(等離子刻蝕機(jī)理)

Thepositiveionaredrawntothecathode,andthenegativeionstoanode.Inamediumpressurediodereactor,only1in50,000ofthegasmoleculesareionized.Therefore,ionsarenotthemaindriversintheetchprocess,althoughtheyplayamajorrole. Becausefreeradicalsareneutral,theybehavemuchlikestandardgasmolecules.Whenagasmoleculefragmentsintheplasma,eachfreeradicalformedtakesupasmuchspaceastheoriginalmolecule.(Thisiswhythepressurejumpswhenaplasmaignites)Theyaremorereactivethantheywereintheiroriginalform,andareimportantetchratedrivers.Freeradicalsareverylong-livedinavacuumenvironment.Plasmaetchmechanism(等離子刻30Plasmaetchmechanism(等離子刻蝕機(jī)理)Plasmaetchmechanism31PlasmaetchmechanismPlasmaetchmechanism32CF4etchChemicalreaction(CF4刻蝕化學(xué)反應(yīng))CF4etchChemicalreaction(33Plasmaetchmechanism(等離子刻蝕機(jī)理))Plasmaetchmechanism(等離子刻34Plasmaetchmechanism(等離子刻蝕機(jī)理)FewnotesinCF4plasmaetch

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

(等離子刻蝕種類(lèi))

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(等離子刻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

(腐蝕氣體和低壓）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

(腐蝕氣體和低壓）Trendsinplasmaetchchemistr463.3 Etchinggasesandpressure

(腐蝕氣體和低壓）

Pumpsusedinsemiconductorprocess AppliedPressure VacuumRangeMechanicpump 10-2 760-10-3 機(jī)械泵Mechanicpump/blower 10-2 760-10-3 機(jī)械泵+羅茨泵Diffusionpump 10-5 10-3-10-7 擴(kuò)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

(腐蝕氣體和低壓）Pumpsusedinetchprocess

DrypumpstackTurbopumpOilpumpOilpumpStack3.3 Etchinggasesandpressur483.4 Etchprocesshighlight

(腐蝕工藝簡(jiǎn)介)PolysiliconetchNitrideetchOxideetchAluminum/aluminumalloyetchPolycidesetchSOGetchW/TiW/TiNetchResistetch(ash)Typeofetchprocess3.4 Etchprocesshighlight(腐蝕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

(腐蝕工藝簡(jiǎn)介)Breakthrough Removena?veoxide---lowerselectivityBulketch(Mainetch) Highetchrate,maximizedselectivity, optimumselectivityOveretch Goodendpointsignal,highselectivityto under-layermaterial* ResistremovalPartiallyorcompletelyremoveresistThemajoretchsteps3.4 Etchprocesshighlight(腐蝕543.5 Etchprocessparameter

(刻蝕工藝參數(shù))Etchrate(everysteps)(刻蝕率）etchuniformity(everysteps)(刻蝕均勻度）Selectivity(tobottomlayermaterial/ resist/impurityinfilm)(選擇比）Endpointdetection(終點(diǎn)檢測(cè)）Loadingeffect（負(fù)載效應(yīng)）Residue（殘余）Damage（損傷）Throughput（產(chǎn)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(離子銑) Ionbeammillingusestheenergyimpartedtoabeamofions.Theionbeamusuallyconsistsofanionizedinertgassuchasargontoperformetching.Theionswithenergiesinthe300-1500eVrangestrikethebondsthatholdthemtoadjacentatoms.Thisprocessdependsonimpactandenergytransfer,notonthechargeoftheincomingion.Thechargeoneachionintheincidentbeammakestheformationofacollimated,singleenergybeampossible.TheschematicofatypicalionmillingsystemisshowninFigure6.3.6Ionmilling(離子銑) 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. 未來(lái)的刻蝕工藝Polysilicon/PolycideThinnerpolysiliconwillbeused(1500-2000A),therefore,loweretchratecanbetolerated.Undopedpolysiliconwillbeused,theprofilecontrolwillnotbeaissue.(afterpolylineformed,N+dopedforNchannel,andP+dopedforPchannel)Stoponoxintrideorotherexoctichighdielectricconstantmaterialselectivitywillnotbeaissue.(HBreasilyobtaina100:1selectivity.5. 未來(lái)的刻蝕工藝Polysilicon/Polycide78OxideHighdensity,lowpressureplasmawillbedormantforthisapplicationEtchstoponSiNwillbeusedforimprovingselectivityC4H8/CO2etchingchemistrywillbeusedextensivelyforSAC(selfaligncontact)andtrenchstructureNeedlowetchrateandlowdamageplasmaforlowKandporousmaterialetch.5. 未來(lái)的刻蝕工藝Oxide5. 未來(lái)的刻蝕工藝79MetalCupperwillbeusedfornarrowlinetoreplacealuminumalloymaterialUsecupperastheconnectorcannotbeusedtheconventionaletchingprocess,thenewprocessscheme: * etchoxidetrench * sputterseedlayer(TaN) * cupperplating * CMPstoponTaN * etchTaNAluminumalloyfilmforuppermetalonly(thickandwidestructureetching)5. 未來(lái)的刻蝕工藝Metal5. 未來(lái)的刻蝕工藝80ChemicalMechanicalPolish化學(xué)機(jī)械拋光 The1stCPMequipmentstartedinproductionsince1990.Nowmostofsubmicronsemiconductorfa