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ID:58857717
大小:677.50 KB
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时间:2020-09-30
《专题讲座6:英文 CMOS工艺流程ppt课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、BasicCMOSProcessFlowShallowTrenchFormationWellFormationGateFormationSource/DrainFormationSilicideFormation1stInterconnectLayer2ndthroughNthInterconnectLayerPassivation1BasicCMOSProcessFlowStartingPoint:Puresiliconwafer(heavily-doped)withalightly-dopedepitaxia
2、l(epi)layer.Anepilayerisusedtoprovideacleanerlayerfordeviceformationandtoprevent“latch-up”ofCMOStransistors.SiliconSubstrateP+~2microns~725micronsSiliconEpiLayerP-21.ShallowTrenchFormationGrowPadOxide:Averythin(~200Å)layerofsilicondioxide(SiO2)isgrownonthesur
3、facebyreactingsiliconandoxygenathightemperatures.Thiswillserveasastressrelieflayerbetweenthesiliconandthesubsequentnitridelayer.SiliconSubstrateP+SiliconEpiLayerP-PadOxide3ShallowTrenchFormationDepositSiliconNitride:Alayer(~2500Å)ofsiliconnitride(Si3N4)isdepo
4、sitedusingChemicalVaporDeposition.Thiswillserveasapolishstoplayerduringtrenchformation.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitride4ShallowTrenchFormationPatternPhotoresistforDefinitionofTrenches:Oneofthemostcriticalpatterningstepsintheprocess.0.5-1.0μmo
5、fresistisspun,exposed,anddeveloped.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitridePhotoresist5ShallowTrenchFormationEtchNitrideandPadOxide:Areactiveionetch(RIE)utilizingfluorinechemistryisused.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitridePhotoresist6Sha
6、llowTrenchFormationEtchTrenchesinSilicon:Areactiveionetch(RIE)utilizingfluorinechemistryisused.Definestransistoractiveareas.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitridePhotoresistTransistorActiveAreasIsolationTrenches7ShallowTrenchFormationRemovePhotores
7、ist:Anoxygenplasmaisusedtoburnofftheresistlayer.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitrideTransistorActiveAreasIsolationTrenches8ShallowTrenchFormationFillTrencheswithOxide:ACVDoxidelayerisdepositedtoconformallyfillthetrenches.Theoxidewillprevent“cross
8、-talk”betweenthetransistorsinthecircuit.SiliconSubstrateP+SiliconEpiLayerP-SiliconNitrideFuturePMOSTransistorSiliconDioxideFutureNMOSTransistorNocurrentcanflowthroughhere!9ShallowTrenchFo
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