掩膜版(mask)制造技术

Title:PhotomaskMakingPage1of24Author:RogerRobbins3/6/2007DocumentNumber:SP-07-001TheUniversityofTexasatDallasPhotomaskMakingRogerRobbins3/6/2007TheUniversityofTexasatDallasErikJonssonSchoolofEngineeringTitle:PhotomaskMakingPage2of24Author:RogerRobbins3/6/2007DocumentNumber:SP-07-001TheUniversityofTexasatDallasPhotomaskMakingRogerRobbins3/6/2007TableofContentsPhotomaskMaking..........................................................................................................2TableofContents........................................................................................................2PhotomaskMaking..........................................................................................................3Purpose.......................................................................................................................3Introduction..................................................................................................................3Mask“Color”................................................................................................................3ProcessDescription.....................................................................................................4Step1:PlasmaCleaning..........................................................................................4Step2:HMDSApplication........................................................................................5Step3:ResistApplication........................................................................................6Step4:Pre-Bake......................................................................................................8Step5:LithographicPatterning................................................................................8Step6:PostBake..................................................................................................10Step7:Develop......................................................................................................10Step8:PlasmaDe-scum........................................................................................11Step9:CrEtch.......................................................................................................12Step10:ResistRemovalandMaskClean.............................................................12Step11:FinalInspection........................................................................................14Conclusion.............................................................................................................14AppendixA....................................................................................................................15AppendixB....................................................................................................................18Title:PhotomaskMakingPage3of24Author:RogerRobbins3/6/2007DocumentNumber:SP-07-001TheUniversityofTexasatDallasPhotomaskMakingRogerRobbins3/6/2007PurposeThispaperdescribesastartingprocessformakingphotomaskswiththetoolsintheUTDCleanroom.Specialneedsmaydictatevariationsinthisprocessflow.IntroductionPhotomasksaregenerallyChromecoatedglasslithographictemplatesdesignedtoopticallytransferpatternstowafersorothersubstratesinordertofabricateplanartypedevicesofalltypes.Basicallythepatterninformationiscreatedinadrawingpackageandstoredinadatabase,reformattedandtransferredtoalithographytool–laserwriterore-beamwriterinourcase–thenprintedinalayerofphotoresistcoatedontothephotomaskplate.TheimagedpatternisnextdevelopedtoformatemplateovertheopaqueChromeandthentheChromeisetchedawaywheretheresistisclear.Aftertheetchprocessiscomplete,theremainingphotoresistisremoved,theplatecleaned,andthenstoredforlateruseinanopticalprinter.ThispaperwilldescribeindetailallthefundamentalprocessstepsrequiredtofabricateaphotomaskintheUTDCleanroomLabs.Figure1.Exampleofstandardphotomasks:“Clearfield”onleft,“darkfield”onrightMask“Color”First,therearesomekeydetailstodiscussthatdeterminewhat“color”photomaskyouwillneedtomake,(Figure1).Normally,weuse“positive”photoresisttomakemasks.Thismeansthatwhereverlightexposesthephotoresist,thedeveloperwillwashawaythephotoresist.Thisexposedarea,then,willexposetheChromeandallowittobewashedawayintheacidetchsolution,leavingholesintheChromethroughTitle:PhotomaskMakingPage4of24Author:RogerRobbins3/6/2007DocumentNumber:SP-07-001TheUniversityofTexasatDallaswhichlightwillpasstoexposethesubstrateduringthepatterntransferprocess–(DarkFieldmaskcolor).Followingthatlogic,ifthesubstratealsohaspositivephotoresist,themaskwillallowexposuretothesubstrateinthesamepatternastheclearregionsonthemask.Thedevelopmentofthesubstrateresistwillproduceexposedareasinthesamelocationastheclearareasonthemask.Thiswillallowanetchprocesstotransfertheclearareapatterntoanunderlyingfilmbyetchingawaytheunderlyingfilminthecleararea.Thismayseemsimpletothecasualobserver,butthereisacomplicationwhenyouconsiderthecommon“lift-off”processwhichwillchangethe“color”ofthepatternonthesubstrate.Inthelift-of