單片集成MEMS技術(shù)中英文翻譯、外文文獻(xiàn)翻譯、外文翻譯

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XXXXXXX設(shè)計(jì)（XX）譯文

姓名學(xué)院專業(yè)班級(jí)指導(dǎo)教師

20XX年

06月15

日MonolithicallyintegratedMEMStechnologyInthepast20years,CMOStechnologyhasbecomeamajorintegratedcircuitmanufacturingtechnology,manufacturingcostsdeclineatthesametime,yieldandproductionhasalsobeengreatlyimproved,COMStechnologywillcontinuetoincreaseintegrationandreducedevelopmentofaspecialsize.Today,CMOSintegratedprocessnotonlybeusedinthedesignofintegratedcircuits,butalsotobeusedinmanymicro-sensorsandmicro-actuator,soitcanbeintegratedcircuitsandmicro-sensorintegratedwithapowerful,intelligentsensors.Withmicro-sensorconstantlyexpandingthescopeofapplicationofthesensorincreasinglyhighdemandsofthefuturemicrosensorthemainrequirementsare:miniaturizationandintegrationoflow-powerandlow-costhigh-precisionandlonglife;-andintelligent.Micromachinedsiliconintegratedcircuitsandtheintegrationofintegration,tomeettheabove-mentionedrequirements.Atpresent,themajorityofproductsintegratedsensorusinghybridintegrated,monolithicintegrationofaverysmallpercentage.Andtherealizationofsingle-chipintegrationisthekeytoachievingintelligentsensors,inparticularmonolithicintegratedMEMSsensortechnologyistoday'ssystem-on-chipcanachieveoneofthekeytechnologies.Clearly,monolithicintegrationofthevarioustechnicaldifficultiesanalysisofMEMSandhavealreadygiventhevariousmonolithicintegrationofMEMStechnologyisessential.1.MonolithicintegrationofMEMStechnologyadvantagesandthechallengesfacing。MEMSandCMOSachieveworkingtogether,theseparatemanufacturingCMOSMEMSsensorsandintegratedcircuits,andthencutfromtheirchips,fixedinacommonsubstrate,and,bondedconnection,therebybringingthetwointegration,Thisistheso-calledmixed(hybrid)method.ThismethoddoesnotproduceMEMSmanufacturingprocessforCMOScircuitspollutionAtthesametime,boththeproductionprocessNoninterference.However,duetosignalbondingpointandfuses,resultinginhigh-frequencyapplications,declineinthequalityofsignaltransmission,andtodeveloptwoproductionlinestoincreasethecostoftheproduct.Inordertoaddresssomeperformanceissues,andlowermanufacturingcosts,andproposedtodointhepartofMEMSandCMOScircuitswithasubstrate,whichisproducedcompatiblewithCMOStechnologyormonolithicintegratedMEMStechnologycalledCMOS-MEMStechnology.Thismethodrelativehybridmethodgenerallyhavethefollowingadvantages:First,theperformancecanbegreatlyimproved,becauseparasiticcapacitanceandcrosstalkphenomenoncanbesignificantlyreduced;second,hybridmethodrequiressophisticatedtechnologytoreducepackagingSensorInterfaceaffected,andmonolithicintegrationrequirespackagingtechnologyisrelativelysimpleandtherefore,lowercostsensors;third,monolithicintegratedsensorarraysensortechnologyistheneedtoovercomethearraysensorandexternaldecodingcircuitaneffectiveinterconnectbottleneck;Fourth,thedevelopmentofmonolithicintegratedmixeddevelopmentofMEMSproductsthanMEMSproductsforashorttime,andtodeveloplowcost.MonolithicintegrationofMEMStechnologyundersomeofMEMSdevicesandCMOScircuitcanbedividedintodifferentorderprocessingbeforeCMOS(pre-CMOS),mixedCMOS(intermediate-CMOS),andaftertheCMOS(post-CMOS)integratedapproach.Post-CMOSapproachisintheprocessingofsiliconCMOScircuitsEnd,throughsomeadditionalMEMSmicro-processingtechnologytoachievemonolithicintegratedMEMSsystem,atpresent,monolithicintegrationofMEMStechnologyinthiswaymainlybased.Post-CMOSapproachisthemainissueonMEMSprocessingtemperatureCMOScircuitperformanceinfrontofanimpactonmoreseriousisthatthetechnologybehindhigh-temperatureMEMSprocessingtemperatureandmetalCMOSprocessaheadofincompatibility.InthepresentstudyasthemostpolysiliconlayerstructureoftheMEMSexample,thedensificationofphosphorusglassannealingtemperatureis950℃duetoastructuralpolysiliconlayerofstressannealingtemperaturereached1050℃,whichwillenableCMOSdevicesjunctiondepthmigrationoccurred.Inparticular800℃shallowjunctiondevicesjunctiondepthmigrationwillaffectdeviceperformance.Ontheotherhand,theconventionalaluminummetallizationprocess,whenthetemperaturereaches400-450℃,thereliabilityofCMOScircuitswillbeseverelyaffected.Fromtheabovewecanseethat:howtoovercomebehindhigh-temperatureMEMSprocessingtemperatureonthemicro-structureofthefrontendprocessinghasbeentheimpactofCMOScircuitsintegratedMEMSsingle-chipsolutioniskeytothesystem.Atpresent,theinternationalcommunityisessentialtoresolvethisissuethroughthreeways:Firstistheinterconnectionofrefractorymetalsinsteadofaluminummetalinterconnect,forexample,theUniversityofBerkeleytoreplacetungstenaluminummetalinterconnectprogrammes,suchfollow-upincreasedtoleranceMEMSprocessingforhightemperature;Thesecondisproducedbyfindinglowtemperaturemechanicalpropertiesandexcellentsubstitutematerialsasstructuralpolysiliconlayer;thirdwayistouseitsexistingstructureCMOSMEMSlayerasalayerstructure.Pre-CMOSintegratedapproachistocreatestructureMEMSmanufacturingCMOScircuits,althoughthisintegratedCMOStechnologytoovercomepost-CMOSmethodofhigh-temperatureMEMSTechnologyonCMOScircuitsaffected,butbecauseoftheexistenceofmicro-verticalstructure,andtherefore,theresensorandcircuitinterconnectionlevelcoverage,butalsointheprocessofCMOScircuitsonthemicro-structureprotectionisalsoaneedtoconsidertheissue.Evenfine-tunetheoptimizationofCMOSprocess,suchas:gateoxidemaybeheavilydopedlayerimpactofthestructure.Inaddition,theMEMStechnologycannotprocessanyofthemetalorothermaterials,suchaspiezoelectricpolymers,andsoon,makesthismethodonlysuitableforsomespecialapplications.Intermediate-CMOScircuitsintheCMOSproductionprocesstoinsertsomeMEMSmicro-processingtechnologytoachievemonolithicintegratedMEMSapproach.Thisapproachhasbeenverymatureandhavealotofcommercializationofproducts,isthefirststudyofasingle-chipintegrationmethodistosolvethepre-andpost-CMOSCMOSmethodeffectivemethodproblems,butduetotheneedfortheexistingstandardCMOSorlargerBiCMOSprocesschanges,therefore,theuseofthismethodislimited.2.ThemainmonolithicintegratedMEMStechnologystatusAtpresent,themonolithicintegrationofMEMStechnologymainlytopost-CMOStechnologies,throughaseriesofcompatiblewithCMOSprocessonthesurfacemicro-machiningandprocessingtoachievemonolithicintegrationofMEMS.Canbedividedintotwokinds:oneisinthetoplayerCMOSstructuretoastructurelayerdepositionmicro-machining;theotherisdirectlyCMOSlayerstructureastheoriginalstructureoftheMEMSmicro-machined.2.1DepositionofnewstructuralmaterialsforthestructureofintegratedMEMStechnology2.1.1Polysiliconlayerstructureasthesurfacemicro-machiningtechnologyintegrationThisprocessistypicalofmodulesdevelopedattheUniversityofBerkeleyIntegratedCMOSandMEMSTechnology(modularintegrationofCMOSwithmicro-structures,MICS),thismethodisforthemicro-structuralpolysiliconlayer,phosphorussiliconglass(PSG)asasacrificiallayerThesurfacemicro-machiningtechnology.Arefractorymetaltungstenmetalinterconnectinsteadofaluminummetalinterconnecttobearbehindthepolysiliconproductionneedsofmicro-structureofhigh-temperature,butat600℃,tungstenandsiliconformeasilyresponsebytheUniversityofBerkeleyintheContactsreleaseaTiNbarrierlayertoaddressthisproblem.MICSprocessisthebasicprocess:thecompletionoftungstenmetalCMOSprocess,thedepositionof300×10-10nmlow-temperatureoxide(LTO),andthen,lowpressurechemicalvapordeposition200×10-10nmprotectionofthesiliconnitridefilmhasbeenproducedCMOScircuits,micro-structureandcorrosionEndCMOScircuitcontacthole,No.1layerdepositionscenedopedpolysilicon(350×10-10),asCMOScircuitsandmicro-structureofinterconnectionlines,intheabovedepositiontoaumPSGthickasasacrificiallayerthicknessanddepositionof2umpolysiliconlayerstructure.No.2throughanotherlayerpolysilicondepositionofalayerof0.5umPSG,aswellasnitrogenenvironmentinthe1000℃rapidthermalannealingfor1minasastructuretoreducestresspolysiliconlayer.Finally,thestructureofgraphicsandpolysiliconetchingoutitscorrosionlayerbelowthesacrifices(PSG)forthereleaseofmicro-structure.2.1.2Othermaterialsforthestructureofthesurfacemicro-machiningtechnologyintegrationPolycrystallinesilicongermaniumpolysiliconnotonlywiththeexcellentmechanicalpropertiessimilar,and,lowtemperaturedepositioncompatiblewiththeCMOSprocess,therefore,isbeingextensivelystudied.DevelopedattheUniversityofBerkeley-basedstructurallayerofsilicongermaniumtechnologyandMICStechnologysimilar.Majortechnologicalinnovations:First,theprotectivelayerusingdifferentmaterials,before835℃MICSprocessistheLPCVDsiliconnitride,andnowitisusingatwo-tierLTOandintermediatefolderisnotastereotypicalsilicon(a-Si)asaCMOScircuitprotectivelayer,inwhichthetwo-stepdepositionofa-Si,thefirststepinthedeposition450℃;stepdepositioninthe410℃,thiswillnotdamagethetemperatureofaluminummetalCMOScircuit;Second,thelowamylinplotstructureasatemperaturepolysiliconlayerofgermaniummaterials,thelowpressurechemicalvapordeposition(LPCVD)temperatureonly400℃usingrapidthermalannealingtemperatureofonly5.5℃for30s.MICSandthetemperaturepolysilicondepositionofmorethan600℃.Fromtheabovetwopoints,wecanseethatthewholefollow-upMEMSprocessingtemperaturedoesnotexceed450℃,therefore,notofaluminummetalinterconnectCMOScircuitshavegreatlyaffected.Aluminumusedasastructuralmaterialwillbeagreatsuccess,themostsuccessfulistheTexasInstrumentsdevelopedcryogenicsurfacemicro-machiningtechnology,andusethistechnologysuccessfullyproduceddigitalmicromirrordevice(DMD).Technicalinnovationintheuseofsputteringperformanceasaluminumstructuralmaterial,andusingphotoresistasasacrificiallayer,whichmakeslow-temperaturepost-processingproductionhasbeenbelowtheSRAMcellswerenotdamaged.Leadzirconatetitanate(PZT)ofthematerialhasanexcellentresultpiezoelectricproperties,pyroelectricpropertiesofferroelectricpropertiesanddielectricpropertiesandiswidelyusedinferroelectricmemory,aswellashigh-dielectricmaterials.Atthesametime,wecanalsouseleadzirconatetitanatepiezoelectriceffectproducedmicro-sensorsandmicro-actuators.PZTthinfilmsilicontechnologyandintegrationtechnologycompatible,suchasthepresentbasedonthemetal-organicchemicalvapordeposition(OCVD)MethodsPZTthinfilmstemperaturehasbeenreducedto430to75℃,thetemperatureislower,therefore,useofsuchmaterialsasstructurallayerisaveryhopefulandCMOSprocessintegration.2.2CMOSstructuretotheoriginallayertothestructureofintegratedMEMStechnology2.2.1Sacrificealuminummicro-machiningtechnologyIfCMOSmetalcompoundsusedfortheexpenseofmaterials,theremaybefullycompatiblewithCMOStechnologyandsurfacemicro-machiningsmallart,thismethodiscalledsacrificealuminumetching(sacrificialaluminumetching,SALE).InmanyCMOSprocess,usetwolayersofaluminumalloybyametallayer.No.1asasacrificiallayerofmetalwasremoved,cancreatemetaldielectriccompounds;Layer2andpassivationofthemetalcomponent,2-layermetalbetweentwodielectricbetweenappropriatestructure,theycouldserveasamirrorelectrodes,heatorelectricresistanceregulator.Thebasicprocessinclude:(1)theprotectionofelectricalcontactsarenotconnectedetching(2)corrosionsacrificealuminumlayer;(3)removalrinsedBoundarystructureinsidetheetchingagent;(4)-dryingbodies.2.2.2Monocrystalsiliconetchingandmetalactivationmethod.Monomersiliconetchingandmetalactivationmethod(singlecrystalreactiveetchingandmetallization,SCREAM)canbeusedformanufacturing,beam,thebridgestructure,andevensiliconcanbeusedtocreatemorecomplexstructures.ThisapproachstartsattheEndmanufacturesiliconCMOScircuits,firstofall,alayerofcoveragedepositioncontactholesiliconoxide,oxidelayertoprotectitfromthebackofCMOScircuitsaffected,andthroughreactiveionetching(RIE)ofthisgraphicsOxidelayershieldinglayer;thenRIEetchingsilicontrench,thedepthofupto10um,siliconoxidethinfilmdepositiondown,andthelevelofcoverageinthesidesurface.Byreactiveionetchingoftheoxidesurfaceleveloffduetoaverticalsurfacetobeprotected,thesecondreactiveionetchingsilicon;Finally,theisotropicetchsilicon,thereleaseofthemicrostructureofasuspension,atthesametime,etchingcontactholeoxides,andSputteringmetal,thislayerofmetaldepositiontotheaspectratioofthebeamintoacapacitiveelementswiththickresistmaskingagentforthegraphicsmodeofmetallayers.AseachstepofSCREAMarebelow300℃underthetemperatureand,therefore,iscompatiblewithCMOScircuits.2.2.3LargeaspectratioofCMOS-MEMSTechnologyGamegleMelloaUniversityandthedevelopmentofCMOS-compatibledryetchingmethod,whichisotropicsiliconetchapplicationshaveinsulationfilm,CMOSdielectricandmetallayersinthisprocess,notonlyforthemetalinterconnect,butalsoasamicro-mechanicalstructuretail.Basicprocess:First,thestandardCMOSprocessusingthree-metalprocesstoachieve0.5upmNWell,secondly,metallayers1and2wereusedaselectricalactivitylayer,andlayer3asamicro-machiningetchingmask.ApplicationofthecompoundCHF3/O2reactiveionetching(RIE),theentirechippassivationlayertoberemoved,inthethree-tierregionaldisconnectmetal,CMOSlaminatedfilmhasbeenetchedtothebasement,andabovecoveredwithLayer3CMOSmetalthinfilmlaminatedretainedintact;Finally,theuseofSP6/O2plasmaetchinginthemicro-structuralwallnotunderisotropicetchsiliconsubstrate.Narrowinsulatinglayerandconductivelayerfusedtocreatebeamsandbridges,suchas:Combdrivethemicro-structure.2.2.4ProcessingCMOS-MEMSTechnologyMainlythroughtheetchingofsiliconsubstrates,suchasprocessingtechnologytoformthenecessaryMEMSstructure,thetechnologymainlytotheUniversityofZurich-based.Canbeviewedinapositiveetchingsiliconsubstrate,butalsofromnegativeetchingsiliconsubstrate,usinganisotropicetching(100)inthedirectionofthecharacteristicsofthesiliconetchingcouldbepositivenotclosedmicro-structure,suchasbeamsandsupportfilm,thechoiceofetchingcanbetetramethylammoniumhydroxidesolution(TMATH)orethylenediaminesolution(EDP).Fromwhathasbeendonethroughthebackofthesiliconwaferofsiliconcanbepittingtheclosureofthedielectricfilm,theneedforadefinitionofadditionalpatchmaskthesizeofthecommonlyusedcandleisengravedonKOH.

XeF2dryetchingusingthepost-CMOStechnologyhasalsomadegreatdevelopment.XeP2isananisotropicetchingofsilicon,etchingathighvelocity,itisaninertgasxenonrarecompounds.XeP2neitherICinsulatinglayeretching,etchingaluminumormetalcompounds,therefore,andCMOScompatible.Aftertheappropriateregionaldesign,connectivityandprocessingmask,openedindesignatedpartsinsulatinglayer,sothatlocalexposuretosiliconsubstrateetchingagent.XeF2becausethatisnotetchedceramic,notplasticetchingandthussuitableforCMOSintegratedmicro-processingsystem.IntheuseofthismethodcanbecompletedwithCMOSchipmicro-etchingmaskinstitutions.3.DevelopmentTrendMonolithicallyintegratedMEMStechnologyhasbeendevelopingformorethan10years,hasbeentherapiddevelopmenthasalsoseentheemergenceofaMEMSmanufacturingservicesorganizationsandenterprises,whichwillbesomespecialorganizationsordirectlyfromtheICmanufacturerstoprovideMEMSprocessing.ICMicrosystemsrepresentativeofthedirectionoftechnologydevelopmentorganizations,includingtheUnitedStatesandEuropeTIMACMPMOSIS.Europractice;NorthKaluonastateCroonsIntegratedMicrosystemsInc.,inadditiontoprovidingthebasicCMOSprocess,thebodyalsoprovidesmicro-machiningandsurfaceemblemprocessing,LIGAprocess,aswellasmulti-userMEMStechnology;theUnitedStatesSandiaNationalLaboratorydevelopmentofthemulti-storeyhyperplanepolysilicontechnologyhasbeencommercializedinEuropeintheapplication-specificintegratedcircuitmanufacturingtechnologyresearch,includingAustriaMicrosystemsandSwitzerland'sEMMicroelectronics.Therearemanyspecialsilicon-basedsensortechnologyhasalsobeenfindingout,forexample,Germany'sLuobaiteboOxfamandtheNorwegianSensoNorcompanies.Judgingfromthecurrentsituation,integratedMEMStechnologywillhavethefollowingtrends:(1)post-CMOSintegratedapproachwillcontinuetobethemainfuturedevelopmentoftechnology,andtheexistinglaboratorieshavedevelopedvariouspost-CMOSsingle-chipintegratedMEMStechnologyindustry;(2)intheintegratedMEMSsystemmorecomplexintegratedcircuitincludingdigitalinterfacesandmicrocontrollers,sothatamorepowerful,cheaperintelligentsystems;(3)thedevelopmentofCMOSchippackagingtechnologyprotectionagainstenvironmentalimpacts,notonlyneedtodevelopasystemtointegratetheMEMSpackage,butalsoneedtoadapttothedevelopmentofthesingle-chippackageintegratedMEMStechnology.4.ConcludingremarksMonolithicIntegratedIntelligentMEMSsensoristhekeytothedevelopmentofICindustryisanimportantdirection.Althoughvariousmethodsaresomeproblemsstillexist,however,withitsconstantresearchandCMOSprocesscompatibilityproblemswillbeallthesolutions.Inthispaper,monolithicintegrationofMEMStechnologytotherequirementswerediscussed,andmonolithicintegrationofvariouscharacteristicsofMEMStechnology,aprocess,atthesametime,alsogivesfuturemonolithicintegrationofMEMStechnologydevelopmenttrendofthefuture.單片集成MEMS技術(shù)在過去的20年中，CMOS技術(shù)已成為集成電路主要制造工藝，制造成本下降的同時(shí)，成品率和產(chǎn)量也得到很大提高，COMS工藝將繼續(xù)以增加集成度和減小特制尺寸向前發(fā)展。當(dāng)今，CMOS集成工藝不僅被利用在集成電路設(shè)計(jì)上，而且，也被利用在很多微傳感器和微執(zhí)行器上，這樣可以把微傳感器與集成電路集成在一起，構(gòu)成功能強(qiáng)大的智能傳感器。隨著微傳感應(yīng)用范圍的不斷擴(kuò)大，對(duì)傳感器的要求也越來越高，對(duì)未來微傳感器的主要要求是：微型化和集成化；低功耗和低成本；高精度和長(zhǎng)壽命；多功能和智能化。硅微機(jī)械和集成電路的一體化集成，可以滿足上述要求。目前，集成傳感器的產(chǎn)品多數(shù)采用混合集成，單片集成的比例很小。而實(shí)現(xiàn)單片集成是實(shí)現(xiàn)傳感器智能化的關(guān)鍵，特別是單片集成MEMS傳感器技術(shù)也是當(dāng)今片上系統(tǒng)芯片能否實(shí)現(xiàn)的關(guān)鍵技術(shù)之一。可見，對(duì)各種單片集成MEMS技術(shù)難點(diǎn)進(jìn)行分析以及給出目前已有的各種單片集成MEMS技術(shù)是非常必要的。1.單片集成MEMS技術(shù)的優(yōu)勢(shì)和面臨的挑戰(zhàn)實(shí)現(xiàn)MEMS和CMOS共同工作是分別制造MEMS傳感器和CMOS集成電路，然后，從各自的晶片切開，固定在一個(gè)共同的襯底上，并且，連線鍵合，這樣就實(shí)現(xiàn)兩者的集成，這就是所謂的混合（hybrid）方法。這種方法不會(huì)產(chǎn)生MEMS制造過程對(duì)CMOS電路的污染，同時(shí)，兩者生產(chǎn)過程互不干擾。但是，由于信號(hào)經(jīng)過鍵合點(diǎn)和引線，導(dǎo)致在高頻應(yīng)用時(shí)，信號(hào)傳輸質(zhì)量下降，并且，開發(fā)兩套生產(chǎn)線增加了產(chǎn)品的成本。為了解決一些性能問題，并降低制造成本，提出把MEMS部分做在和CMOS電路同一塊襯底上，也就是產(chǎn)生了與CMOS工藝兼容單片集成MEMS技術(shù)或叫CMOS-MEMS技術(shù)。這種方法相對(duì)混合方法總的來說有如下優(yōu)勢(shì)：第一，性能能得到很大的提高，因?yàn)榧纳娙莺痛當(dāng)_現(xiàn)象可以顯著減小；第二，混合方法需要復(fù)雜的封裝技術(shù)以減小傳感器接口的影響，而單片集成方法需要的封裝技術(shù)相對(duì)簡(jiǎn)單，所以，降低傳感器成本；第三，單片集成傳感器技術(shù)也是陣列傳感器的需要，是克服陣列傳感器與外圍譯碼電路互連瓶頸的一種有效方法；第四，開發(fā)單片集成MEMS產(chǎn)品比開發(fā)混合MEMS產(chǎn)品所需的時(shí)間短，而且，開發(fā)成本低。單片集成MEMS技術(shù)根據(jù)MEMS器件部分與CMOS電路部分加工順序不同可以分為前CMOS（pre-CMOS）、混合CMOS（intermediate-CMOS）及后CMOS（post-CMOS）集成方法。post-CMOS方法是在加工完CMOS電路的硅片上，通過一些附加MEMS微細(xì)加工技術(shù)以實(shí)現(xiàn)單片集成MEMS系統(tǒng)，目前，單片集成MEMS技術(shù)主要以這種方法為主。post-CMOS方法主要問題是MEMS加工工藝溫度會(huì)對(duì)前面的CMOS電路性能產(chǎn)生影響，更為嚴(yán)重的是后面高溫MEMS加工工藝溫度與前面CMOS工藝金屬化不兼容。以目前研究最多的多晶硅作為結(jié)構(gòu)層的MEMS為例，使磷硅玻璃致密化退火溫度為950℃，而使作為結(jié)構(gòu)層多晶硅的應(yīng)力退火溫度則達(dá)到1050℃，這將使CMOS器件結(jié)深發(fā)生遷移。特別是800℃時(shí)淺結(jié)器件的結(jié)深遷移就會(huì)影響器件的性能。另一方面，采用常規(guī)鋁金屬化工藝時(shí)，當(dāng)溫度達(dá)到400-450℃時(shí)，CMOS電路可靠性將受到嚴(yán)重的影響。從以上可以看出：如何克服后面高溫MEMS微結(jié)構(gòu)加工溫度對(duì)前面的已加工完的CMOS電路影響是解決單片集成MEMS系統(tǒng)關(guān)鍵所在。目前，國(guó)際上解決這個(gè)問題基本是通過3種方式：第一種是以難熔金屬化互連代替鋁金屬化互連，如，伯克利大學(xué)的以鎢代替鋁金屬互連方案，這樣提高容忍后續(xù)加工MEMS所需的高溫；第二種方式是通過尋找低制作溫度且機(jī)械性能優(yōu)良的材料代替多晶硅作為結(jié)構(gòu)層材料；第三種方式是利用CMOS本身已有結(jié)構(gòu)層作為MEMS結(jié)構(gòu)層。pre-CMOS集成方法是先制造MEMS結(jié)構(gòu)后制造CMOS電路，這種集成CMOS技術(shù)雖然克服post-CMOS方法中MEMS高溫工藝對(duì)CMOS電路的影響，但由于存在垂直的微結(jié)構(gòu)，所以，存在傳感器與電路互連臺(tái)階覆蓋性問題，而且，在CMOS電路工藝過程中對(duì)微結(jié)構(gòu)的保護(hù)也是一個(gè)需要考慮的問題。甚至已優(yōu)化微調(diào)的CMOS工藝流程，例如：柵氧化可能被重?fù)诫s的結(jié)構(gòu)層影響。另外，MEMS工藝過程中不能有任何的金屬或其他的材料，如壓電材料聚合物等，使得這種方法只適合一些特殊應(yīng)用。intermediate-CMOS是在CMOS電路生產(chǎn)過程中插入一些MEMS微細(xì)加工工藝來實(shí)現(xiàn)單片集成MEMS的方法。這種方法已很成熟，并已有很多商品化產(chǎn)品，也是研究最早一種單片集成方法，是解決pre-CMOS和post-CMOS方法存在問題有效方法，但是，由于需要對(duì)現(xiàn)有的標(biāo)準(zhǔn)CMOS或BiCMOS工藝進(jìn)行較大的修改，因此，這種方法的使用有一定限制。2.單片集成MEMS的主要技術(shù)現(xiàn)狀目前，單片集成MEMS技術(shù)主要以post-CMOS技術(shù)為主，通過一系列的與CMOS工藝兼容的表面微細(xì)加工和體加工實(shí)現(xiàn)單片集成MEMS。又可分為2種：一種是在CMOS結(jié)構(gòu)層上面再淀積一層結(jié)構(gòu)層的微加工；另一種是直接以CMOS原有的結(jié)構(gòu)層作為MEMS結(jié)構(gòu)層的微加工。2.1淀積新的結(jié)構(gòu)材料作MEMS結(jié)構(gòu)的集成技術(shù)2.1.1多晶硅作為結(jié)構(gòu)層的集成表面微細(xì)加工技術(shù)這種工藝典型代表是伯克利大學(xué)開發(fā)模塊集成CMOS與MEMS工藝（modularintegrationofCMOSwithmicro-structures，MICS），這種方法是以多晶硅為微結(jié)構(gòu)層，磷硅玻璃（PSG）作為犧牲層的表面微細(xì)加工技術(shù)。采用難熔金屬鎢的金屬化互連代替鋁金屬化互連以承受后面的生產(chǎn)多晶硅微結(jié)構(gòu)所需要的高溫，但是，在600℃時(shí)，鎢容易與硅形成反應(yīng)，伯克利大學(xué)是通過在接觸孔上放一層TiN阻擋層來解決這一問題的。MICS工藝基本流程是：完成鎢金屬化的CMOS工藝后，淀積300×10-10nm低溫氧化物（LTO），然后，低壓化學(xué)氣相淀積200×10-10nm的氮化硅薄膜保護(hù)已生產(chǎn)的CMOS電路，腐蝕完微結(jié)構(gòu)與CMOS電路的接觸孔后，淀積第1層現(xiàn)場(chǎng)摻雜多晶硅（350×10-10）作為CMOS電路與微結(jié)構(gòu)的互連線，再在上面淀積1um厚的PSG作為犧牲層以及淀積厚度為2um多晶硅結(jié)構(gòu)層。通過在第2層多晶硅上再淀積一層0.5um的PSG，以及在氮?dú)猸h(huán)境下的1000℃快速退火1min來降低作為結(jié)構(gòu)層的多晶硅應(yīng)力。最后，刻蝕多晶硅結(jié)構(gòu)圖形以及腐蝕掉其下面的犧牲層（PSG）以釋放微結(jié)構(gòu)。2.1.2以其他材料作結(jié)構(gòu)層集成表面微細(xì)加工技術(shù)多晶硅鍺不僅有與多晶硅相似的優(yōu)良機(jī)械性能，而且，淀積溫度低與CMOS工藝兼容，所以，目前被廣泛研究。伯克利大學(xué)開發(fā)的基于硅鍺結(jié)構(gòu)層的工藝與MICS工藝基本相似。主要技術(shù)革新：第一，保護(hù)層采用不同的材料，以前MICS工藝采用835℃的LPCVD氮化硅，而現(xiàn)在則是采用兩層LTO和中間夾一層不定型硅（a-Si）作為CMOS電路保護(hù)層，其中，a-Si分兩步淀積，第一步淀積在450℃；第二步淀積則在410℃，這樣溫度是不會(huì)損壞鋁金屬化CMOS電路；第二，采用低淀積溫度多晶硅鍺作為結(jié)構(gòu)層材料，其低壓化學(xué)氣相淀積（LPCVD）溫度只有400℃，采用快速退火溫度也僅為550℃，時(shí)間為30s。而MICS工藝淀積多晶硅結(jié)構(gòu)溫度則超過600℃。從以上兩點(diǎn)可知，由于整個(gè)后續(xù)MEMS加工溫度不超過450℃，所以，不會(huì)對(duì)鋁金屬化互連CMOS電路產(chǎn)生很大的影響。采用鋁作為結(jié)構(gòu)層材料也會(huì)獲得很大成功，最為成功的是德州儀器開發(fā)低溫表面微細(xì)加工技術(shù)，并用這種技術(shù)成功生產(chǎn)了數(shù)字微鏡設(shè)備（DMD）。技術(shù)革新主要表現(xiàn)在采用濺射鋁作為結(jié)構(gòu)層材料，并且，采用光致抗蝕劑