berkley 半导体工艺讲义16--干法刻蚀.pdf

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1、EE143F05Lecture16ReactiveIonEtching(RIE)Parallel-PlateRF13.56plasmaReactor~MHzwafersSputteringPlasmagenerates(1)Ions(2)ActivatedneutralsEnhancechemicalreactionProfessorNCheung,U.C.Berkeley1EE143F05Lecture16ProfessorNCheung,U.C.Berkeley2EE143F05Lecture16RemotePlasmaReacto

2、rsPlasmaSourcese.g.quartz(1)TransformerplasmacoilsCoupledPlasma(TCP)wafers(2)Electron-biasCyclotronPressureResonancepump1mTorr10mTorrbias~1kV≤(ECR)ProfessorNCheung,U.C.Berkeley3EE143F05Lecture16•SynergismofionbombardmentANDchemicalreactiongivethehighRIErates.ProfessorNCh

3、eung,U.C.Berkeley4EE143F05Lecture16REMOVALofsurfacefilmandDEPOSITIONofplasmareactionproductscanoccursimultaneouslyProfessorNCheung,U.C.Berkeley5EE143F05Lecture16RIEEtchingSequencegasflow51diffusionofdiffusionofbyproductreactantdesorption234Xchemicalreactiongaseousbyprodu

4、ctsabsorptionSubstrateProfessorNCheung,U.C.Berkeley6EE143F05Lecture16VolatilityofEtchingProduct*Highervaporpressure⇒highervolatility*e.g.Si+4F→SiF↑(highvaporpressure)4e.g.Cu+Cl→CuCl(lowvaporpressure)ExamplemaskDifficulttoRIEAl-CuAl-CuMetalalloywithhighCucontentDonotwantC

5、uClresiduesProfessorNCheung,U.C.Berkeley7EE143F05Lecture16Vaporpressureofby-producthastobehigh−∆HvP=PekT0ExampleP1500oCDifficulttoRIEAl-CualloywithhighCucontentAlCl3CuCl1~2%typical[Al-Cualloy]200oC1/TClasetchinggas.2ProfessorNCheung,U.C.Berkeley8EE143F05Lecture16Professo

6、rNCheung,U.C.Berkeley9EE143F05Lecture16ExamplesForetchingSiUseCFgas4*CF→F+CF43+*CF+e⇔CF+F+2e43*Si+4F→SiF↑4F*areFluorineatomswithelectronsProfessorNCheung,U.C.Berkeley10EE143F05Lecture16ProfessorNCheung,U.C.Berkeley11EE143F05Lecture16Aluminum+*CCl+e⇔CCl++Cl+2e43*Al+3Cl→Al

7、Cl↑3PhotoresistCOCHO+Oxxyz2HOxProfessorNCheung,U.C.Berkeley12EE143F05Lecture16HowtoControlAnisotropy?1)ionicbombardmenttodamageexposesurface.2)sidewallcoatingbyinhibitorpreventssidewalletching.ProfessorNCheung,U.C.Berkeley13EE143F05Lecture16Thisexaggeratedpictureshowsapa

8、ssivationlayersothickthatitcanpeelofffromthesidewallPhotoresistontopofSiSiSidewallpassivationfilmsHCl/O