Semiconductor manufacturing processes

Semiconductor devices are built up in a series of nanofabrication processes performed on the surface of substrates made from highly pure single crystal silicon. HOMESemiconductormanufacturingprocesses Semiconductormanufacturingprocesses Semiconductormanufacturingprocesses Semiconductordevicesarebuiltupinaseriesofnanofabricationprocessesperformedonthesurfaceofsubstratesmadefromhighlypuresinglecrystalsilicon.Thesesubstratesareusuallyknownaswafers. Commonlyusedwafersincludethe300mmtype,whichofferstheadvancedminiaturizationrequiredforcutting-edgedevices,and200mmtype,whichisbettersuitedtothemixed,smalllotproductionneededfordevicesfortheInternetofThings(IoT). 1.Cleaning Thesiliconwafersformingthebaseofthesemiconductorarecleaned.Evenslightcontaminationofawaferwillcausedefectsinthecircuit.Therefore,chemicalagentsareusedtoremoveallcontamination,fromultra-fineparticlestominuteamountsoforganicormetallicresiduesgeneratedintheproductionprocess,orunwantednaturaloxidelayersgeneratedduetoexposuretoair. WetStation:FC-3100 SingleWaferCleaner:SU-3200,SU-3300 2.FilmDeposition Thinfilmlayersofsiliconoxide,aluminumandothermetalsthatwillbecomethecircuitmaterialsareformedonthewafer. Thereareavarietyofwaystoformthesethinfilms,including"sputtering",inwhichatargetmaterial,suchasaluminumorothermetal,isbombardedwithions,whichknocksoffatomsandmoleculesthatarethendepositedonthewafersurface,"electrodeposition",whichisusedtoformcopperwirelayers(copperinterconnect),chemicalvapordeposition(CVD),inwhichspecialgasesaremixedtocauseachemicalreactionthatformsavaporcontainingthedesiredmaterial,andthenthemole-culesgeneratedinthereactionaredepositedontothewafersurfacetoformafilm,andthermaloxidation,inwhichthewaferisheatedtoformasiliconoxidefilmonthewafersurface. 3.Post-depositionCleaning MinuteparticlesadheringtothewaferafterthefilmdepositionareremovedusingbrushesorNanospraywithdeionizedwater,orotherphysicalcleaningmethods. SpinScrubber:SS-3200 SingleWaferCleaner:SU-3200,SU-3300 4.ResistCoating Thewafersurfaceiscoatedwithresist(photosensitivechemical).Thenthewaferisspun,causingauniformlayerofresisttobeformedonthewafersurfacebycentrifugalforce. Coat/DevelopTrack:DT-3000,SK-60EX/SK-80EX,SC-80EX 5.Exposure Thewaferisexposedusingshortwavelengthdeepultravioletradiationprojectedthroughamaskonwhichthecircuitpatternhasbeenformed.Onlytheareasoftheresistlayerthatareexposedtothelightundergoastructuralchange,therebytransferringthepatterntothewafer.Thereareavarietyofexposureunits,includingsteppers,whichexposeseveralchipsatatime,andscanners,whichexposethewaferusingaslitthroughwhichlightisprojectedontothewafer. 6.Development Developerissprayedontothewafer,dissolvingtheareasexposedtothelightandrevealingthethinfilmonthewafersurface.Theremain-ingresistareasthatarenotexposedatthispointbecomethemaskforthenextetchingprocess,andthatresistpatternbecomesthepatternonthelayerbelow. Coat/DevelopTrack:DT-3000,SK-60EX/SK-80EX 7.Etching Inwetetching,theexposedthinfilmonthesurfacelayerisdissolvedusingchemicals,suchashydrofluoricacidorphosphoricacid,andremoved.Thisformsthepattern.Thereisalsoadryetchingmethodinwhichthewafersurfaceisbombardedwithionizedatomstoremovethefilmlayer. WetStation:FC-3100 SingleWaferCleaner:SU-3200,SU-3300 8.ImplantationofImpurities Inordertogivethesiliconsubstratesemiconductingproperties,impurities,suchasphosphororboronions,areimplantedinthewafers. 9.Activation Heatprocessingisperformedusingflashlampsorlaserradiationtoactivatethedopedionsimplantedinthewafer.Instantaneousactivationisrequiredtocreatethemicrotransistorsonthesubstrate. FlashLampAnnealingSystem:LA-3100 LaserAnnealer:LT-3100 10.ResistStripping WResistcanbestrippedoffatawetstation,whichuseschemicalsthatremovetheresist,orbyashing,whichremovestheresistbyinducingachemicalreactionusinggases.Thewaferiscleanedaftertheashing. WetStation:FC-3100 SingleWaferCleaner:SU-3200,SU-3300 11.Assembly Thewaferisseparatedintoindividualchips(dicing),thechipsareconnectedtoametalframecalledaleadframeusingmetalwire(wirebonding)andthenenclosedinepoxyresinmaterial(packaging).