Electron-Beam Lithography

DevelopmentofaScintillatingReferenceGridforSpatial-Phase-LockedElectron-BeamLithographybyMarkAlanFinlaysonB.S.,UniversityofMichigan(1998)SubmittedtotheDepartmentofElectricalEngineeringandComputerScienceinpartialfulfillmentoftherequirementsforthedegreeofMasterofScienceinComputerScienceandEngineeringattheMASSACHUSETTSINSTITUTEOFTECHNOLOGYSeptember2001c
MassachusettsInstituteofTechnology2001.Allrightsreserved.Author...................................................................................DepartmentofElectricalEngineeringandComputerScienceAugust10,2001Certifiedby...............................................................................HenryI.SmithKeithleyProfessorofElectricalEngineeringThesisSupervisorAcceptedby..............................................................................ArthurC.SmithChairman,DepartmentCommitteeonGraduateStudents2DevelopmentofaScintillatingReferenceGridforSpatial-Phase-LockedElectron-BeamLithographybyMarkAlanFinlaysonSubmittedtotheDepartmentofElectricalEngineeringandComputerScienceonAugust10,2001,inpartialfulfillmentoftherequirementsforthedegreeofMasterofScienceinComputerScienceandEngineeringAbstractSpatial-phase-lockedelectron-beamlithography(SPLEBL)promisessignificantimprovementinthepatternfidelityandplacementaccuracyofelectron-beamlithographybytheintroductionoffeedbackintothewritingloop.IntheplannedformulationofSPLEBL,thefeedbacksignalisproducedbyareferencegridwhichisbleachedintoathinscintillatinglayerintegratedintotheelectron-beamstack.Formulationandtestingofawidevarietyofmaterialforuseasthescintillatinglayeraredescribed,inadditiontoanumberoftechniquestoimprovethecontrastofthebleachedgrid.ProductionoffiducialgratingsimagedinaSPLEBL-compatibleelectronbeamsystemisdescribed,andpossibleresiststacksthatintegratethescintillatorforuseinSPLEBLarediscussed.ThesisSupervisor:HenryI.SmithTitle:KeithleyProfessorofElectricalEngineering34AcknowledgmentsFirst,thankstomyadvisorProfessorHankSmith.WithouthimIdoubtIwouldhavehadtheopportunityordesiretocometoMITandconductgraduatestudies.Hewasgraciousenoughtoextendtomeaninvitationtobeaundergraduateresearcherinhislabinthesummerof1997,andsincethenhasbeenextraordinarilygenerousinhispostiveregardandsupport.Iamexceptionallygratefultohimforthetimeandenergyhehasinvestedinme.Second,thankstoProfessorsRoyClarke,DonaldUmstadter,andDuncanSteelattheUniversityofMichigan,andDrs.TedBloomsteinandMordyRothschildatMITLincolnLaboratories.Thesemenweremymentors,andIcounttheirencouragementandadviceascrucialtomyscientificdevelopment.Third,thankstomymanycolleagesandcollaboratorsattheNanostructuresLabandMITatlarge.HindyBronsteinforguidingmeinthekindestmannerpossiblethroughmyearlyforaysintochemistry.JimDaleyforhisclearandkindhelp,withoutwhichmostofmyeffortswouldhavebeenfutile.ToddHastingsmycloseSPLEBLcollaborator,forcontinuallyprovidedvaluableinsightandadvice,aswellasbeingoneofthenicestguysI’veevermet.BernhardVogeliformanyincrediblyinstructiveconversationsandinsights,aswellasalotoffun.JamesGoodberletforbeingasourceofmanygoodideasandsuggestions.EuclidMoonforbeingindispensiblefontofinformationregardinganythingcomputer,car,orelectronicmusicrelated,andawillingearforproblemslargeandsmall.MikeWalshforbeinganexceptionallyentertaining(nottomentionknowledgableandhelpful)person.JimmyCarterforhelpingoutwheneverneeded.MaithileeKunda,myRSImentee,forbeinginstrumentalinthefinalroundofdataacquisition.JaimeBeersforbeingagreatfriendandaconstantsourceofsupport.ThemanyothermembersoftheNSLforprovidingarich,instructive,andfunenvironmentinwhichtoworkandbeproductive:SolomonAssefa,DaveCarter,MayaFarhoud,DarioGil,JoeHuang,MikeLim,MitchMeinhold,RajeshMenon,MarkMondol,TomMurphy,MarkusPeuker,MinghaoQi,TimSavas,OliverStoltz,ShingoUchiyama,andFengZhang.MymanycollaboratorsatMITandelsewhere:TimLong,ProfessorTimSwager,Dr.JasonHafner,Dr.DavePflug,andProfessorTayoAkinwande.Fourth,thankstomyfamilyandmymanyfriends,girlfriends,andacquaintenceshereinBostonandintheworldgenerally.Theyaretoonumeroustomention,buthavemademylifeworthliving.Fifth,thankstothegreco-romanintellectualtradition,aswellaswesterncultureandcivilizationgenerally,forprovidingasettinginwhichneuroticobsessionwithanalyticalthinkingwouldgiverisetobothmodernsociety’sloveaffairwithscienceaswellasaplacelikeMIT.Finally,thankstoallthosethatIhavefailedtomentionthroughforgetfulnessorwillfulneglect.56ContentsAbstract3Acknowledgments51Introduction&Motivation131.1PlanarFabricationTechniquesforSemiconductorManufacturing................131.2Electron-beamLithography.....................................151.3Spatial-phase-lockedElectron-beamLithography.........................161.4TheScintillatingFiducialGrid...................................172OverviewofScintillators192.1QuantumMechanicsofScintillatingOrganicMolecules......................192.2ElectronInteractionswithPolymerfilms..............................222.3EnergyTransferinPlasticScintilators...............................232.4PhotochemistryofOrganicFluors.................................242.5Solvationand