硅超大规模集成电路工艺技术金属化

微电子工艺技术第八讲单项工艺金属膜制备-蒸发、溅射、CVD和电镀钱鹤清华大学微纳电子系布线层数和总长度：10层布线，最细线宽在45nm左右，而布线总长度可达到5公里量级；CMOS器件旁的Plug除了金属引线本身的电阻以外，金属与半导体接触界面引入的接触电阻往往对器件特性起重要的作用，通常采用硅化物（Silicide）作为接触材料SpecificContactResistanceMS/CAreaAContactResistancerCSpecificContactResistanceRCDNCRBCRACRCrexpexpSpecificContactResistanceThermionicEmissionTheoryforW5nmTunnelingTheoryforW5nmA*=Richardson’sConstantm*=BarrierHeightRCO=Constant2exp*cmkTBqqTAkCR2*2expcmDNBmsCORCRMetal/MetalAlloyPropertiesMatlrTmaReactionStablemcmCppm/CwithSionSitoCCAl2.7-3.0660-~250250Mo6-1526205400-700~400W6-1534104.5600-700~600Cu1.7108317?NoTiSi213-16154012.5-950MoSi240-10019808.3-1000TaSi238-50~22008.8-10.7-1000WSi230-7021656.3,7.9-1000PtSi28-351398--750CoSi210-18132610.1-950TiN40-1502950-450-500450硅化物的形成温度也是一个重要的考量因素最常用的三种硅化物的性能对比蒸发Evaporation:Simple,straightforward,systemCleanife-gunandgoodvacuumCan’thandlealloysMediocrestepcoverageunlessplanetarydriveisusedMeasurementofthicknessofdepositedfilmrequiresspecialequipment(thicknessmonitor)SputteringPrinciple++Anode(-)TargetSubstrateE(B)IonSputterIonizationDCorRFFieldsVacuump,TNeutralAtomDepositionCathode(+)DiffusionEjectedIonSputtering•Principle•DCBias,IonSputtering•RFSputteringSystem•PressureRange:0.1-1Pa•SputteringModes:RF,DC.Magnetron•Applications:Metals,MetalAlloys,Semiconductors,InsulatorsDCPlasmaGenerationDCGlowDischargeeIonSputterdepositionofconductorsRFsputteringsystemprincipleRFPlasmaDischargeAveragePotentialReversesbiasbeforearepulsivesurfacechargebuildupontheinsulatortobesputteredNoalloyproblem!Goodadhesionoffilm!Metals(DC,RF)aswellasinsulators(RF)PrecisethicknesscontrolviasputteringcurrentxtimemeasurementExpensivesystemsrequiringRFpowersupplyKWofRF,canbepickedupbylonginterconnectsonICchip,damagingtransistors.Radiationdamage(UV)Lotsofvariables,gaspressure,RFpower,plasmapotentialetcetc.ProandConofSputteringVacuumpumpsInthehighpressureregime,vacuumpumpsworkbydilutionpV=RT.Ifthevolumeisexpanded,thepressurefalls.Rotarypumps,RootpumpsetcARootspumpwithapumpingspeedof5500Liters/minuteVacuumPumpsBalzers,1992LeyboldM2000,1999“Clean,LeanVacuumMachine”Turbo’sTheinnardsofaturbopumpAbitlikeajetengineinreverse!电镀工艺原理示意图电镀工艺在Cu线工艺中的应用CVD、PVD和电镀填充性能的比较电镀工艺的填充效果典型的金属化应用场合总结小结:金属与半导体的接触：肖特基接触欧姆接触-或低势垒，或高复合，或高掺杂-利用硅化物已成为通行的做法Cu布线已成为当今IC互连的主流：具有优越的抗电迁移性能和更低的电阻率因刻蚀困难采用大马士革（镶嵌）工艺几种金属膜的制备方法：蒸发、溅射、CVD和电镀孔和深槽填充性能成为一个重要的问题课后请阅读教材第9章的9.3.5-9.3.10节,9.4节,9.5节,以及第11章(下次课讲的内容也与11章相关，可结合着一起看)。作业(下周上课时交!):1.教材中习题9.142.教材中习题11.53.教材中习题11.6