納米材料和納米結(jié)構(gòu)第09講-納米圖案化技術(shù)

納米結(jié)構(gòu)和納米材料ArtificialPatterningofNanostructures

納米結(jié)構(gòu)的人工圖案化技術(shù)

第九講

1IntroductionEnormousAchievementObtainedbyMicroelectronics(微電子取得了巨大的成就)????Richfunctionalityinapplications〔應(yīng)用功能廣泛〕Lowenergyconsumptioninoperations〔運(yùn)行過程能耗低〕Lowcostinfabrications〔制作本錢低廉〕Extendedintonon-electricareassuchasmicro-actuators,-sensorsand〔深入微制動(dòng)器、感應(yīng)器和微DNA探測(cè)等非電子領(lǐng)域〕

micro-DNAprobesFabrication:frommicrometertonanometerscale制造：從微米到納米尺寸???Horizontaldevicefeaturesize:0.18μmto35nm〔水平技術(shù)參數(shù)：0.18微米到35納米〕Verticaldevicefeaturesize:lessthan1.5nm〔垂直技術(shù)參數(shù)：小于1.5納米〕Artificiallypatternednanostructureswithreproducibility,suchasquantum〔人工納米結(jié)構(gòu)圖案的可重復(fù)性，如量子點(diǎn)、光子點(diǎn)陣〕 dots,photoniclatticesetc.Promisingtechniques:electronbeamlithography(EBL),X-raylithography(XRL),extremeultravioletlithography(EUVL)〔有前景的技術(shù)：電子發(fā)射平版印刷術(shù)、X射線平版印刷術(shù)、遠(yuǎn)紫外線平版印刷術(shù)〕 Lithography-平版印刷術(shù)〔光刻〕Similartotraditionalopticallithography,nanolithographyalsoconsistsofthreeparts:〔與傳統(tǒng)光學(xué)印刷術(shù)相同的是：納米光刻也包括3局部〕?Atool〔一種工具〕?Aproperresist〔一種適宜的反蝕藥劑〕?Apatterntransferprocess〔一個(gè)圖案轉(zhuǎn)換過程〕Aspecificnanostructurepatterniscarriedbyanilluminatingsourceandbeamedontoaresistlayersensitivetotheparticularsource,andthepatternintheresististhentransferredontoanunderlyingsubstrate〔具體的納米圖案先通過一種照明材料顯現(xiàn)出來，然后發(fā)射到對(duì)照明源反響敏感的防腐層，最終在反蝕劑的圖案轉(zhuǎn)移到襯底〕Differencesbetweennanolithographyandopticallithography〔納米刻錄和光學(xué)刻錄的區(qū)別〕:?Exposingsources〔顯現(xiàn)材料〕?Masks〔面具〕?resists〔反蝕劑〕2Nanolithography〔納米平版印刷術(shù)〕?8nmlinesinAuPdusinga0.5nme-beam(1976)〔用0.5納米的電子束在AuPd刻錄的8納米圖案〕 2-1ElectronBeamLithography(EBL)〔電子書刻蝕〕EBL:amethodthatallowstheoriginaldigitalimagetobetransferreddirectlytotheinterestedsubstratewithouttheuseofmask〔EBL技術(shù)：是一種可以不用面具直接將初始圖案轉(zhuǎn)移到襯底的方法〕Progresshistory: ?50nmlinesintometalfilmusingaresistwitha10nme-beam(1964)〔在某種反蝕劑用10納米電子束金屬薄膜刻錄的50納米圖案〕?FabricationofAharonov-Bohminterferencedevicebye-beam(1984)〔阿哈羅諾夫－玻姆電子干預(yù)儀的制造〕?1-2nmlinesinmetalhalide(1985)〔在金屬鹵化物刻蝕的1-2納米圖案〕?Fabricationofresearchandprototypenanoelectronicdevices,makingmasks forotheradvancedlithographies〔研究標(biāo)準(zhǔn)納米電子儀的制造，專門用于其他先進(jìn)刻蝕技術(shù)面具的生產(chǎn)〕 EBL-電子束直寫技術(shù)InEBLnanofabrication,workingconditionsatwhichelectronscatteringcausesminimalresistexposureshouldbeespeciallynote〔在EBL刻蝕納米產(chǎn)品的制造中會(huì)引起最小反蝕劑的曝光的電子分散的工作環(huán)境應(yīng)該非常注意〕dTwomodes:veryhigh/lowenergyelectrons〔倆種模式：高能量和低能量電子模式〕?Inhighenergycase,thebeambroadeningintheresistthroughelasticscatteringisminimalandthebeampenetratesdeeplyintothesubstrate〔在高能量模式，電子束有小局部通過彈性散射會(huì)大范圍擴(kuò)散到反蝕劑中并深度滲入襯底〕?Inlowenergycase,electronsareunabletoscatteroverlargedistancesintheresistandthereforebemoreeffective〔在低能量模式：電子不能在反蝕劑中大范圍擴(kuò)散，因此更有效率〕Keyfactorsine-beamnanolithography〔電子束刻蝕的關(guān)鍵因素〕?SpeedandPrecision〔速度和精確度〕?YieldandProcessContro〔產(chǎn)量和過程控制〕l?Fundamentallimitsofe-beam/resistinteractions〔電子束和反蝕劑反響的嚴(yán)格限制〕2-1-1EBLMachineThreeessentialpartsofanEBLequipment:anelectrongun,avacuumsystem,andacontrolsystem〔電子刻蝕儀的3個(gè)重要組成：電子槍，真空系統(tǒng)、控制系統(tǒng)〕Electrongun:generates,accelerates,focuses,andprojectsabeamofelectronsontoasubstrate〔電子槍：產(chǎn)生器，加速器，聚集器和把電子束發(fā)射到襯底的工程〕Vacuumsystem:createsavacuumenvironmentintheelectronguncolumnandtheworkingchamber〔真空系統(tǒng)：在電子槍欄和工作室創(chuàng)造真空環(huán)境〕Controlsystem:providesthemanipulationcapabilityfortheelectronbeamgeneration,propagation,andtiming,aswellascontroloverthesubstratetranslation〔控制系統(tǒng)：對(duì)電子束產(chǎn)生量、增值量和時(shí)間的控制以及轉(zhuǎn)移到襯底過程的控制〕TwowaystogenerateactualpatternsbyEBLmachine:〔電子刻蝕儀產(chǎn)生實(shí)際圖案的倆種方式〕?Rasterscanning:byscanningtheexposingbeaminonedirectionatafixedratewhilethesubstratemovingunderthebeambyacontrolledstage〔光柵掃描：通過在電子束下襯底在控制平臺(tái)下移動(dòng)時(shí)掃描某個(gè)方向顯現(xiàn)的一定速率的電子束〕?Vectorscanning:bydeflectingtheexposurebeamonlytothoseregionsofthesubstratethatrequireexposure〔矢量掃描：通過襯底某個(gè)區(qū)域需要顯現(xiàn)的電子束的偏轉(zhuǎn)〕2-1-2E-beamResists〔電子束反蝕劑〕Electronbeamexposurealtersthenatureoftheresistthroughbreakingthechemicalbonds,withtheresultthatasubsequentimmersionofthesampleinachemicalsolutionremovestheexposedparts(positiveresist),ortheunexposedparts(negativeresist),oftheresistfilmUsuallypolymericsolutionsappliedtothesubstratesurfacebyspincoatinganddriedbybakingtoformauniformthinlayerwhosethicknessshouldnotexceedtheminimumfeaturesizerequiredPMMA(聚甲基丙烯酸甲酯)isastandardhigh-resolutionpolymericresistused,withabestresolutionof10nmlinesInorganicresistwithfarsuperiorresolutiontoPMMA:metalhalide,metaloxide,andsemiconductoroxideswhichundergoaradiolysisreactionunderelectronirradiation(1-5nm)電子束反蝕劑電子曝光通過打斷化學(xué)鍵的方式?jīng)Q定了反蝕劑的性質(zhì)，隨后在化學(xué)試劑中對(duì)樣品的滲入消除試劑的反響局部或剩余局部；通常將聚合物粘在襯底外表，并將其烘烤至不超過要求的最小參數(shù)大??；PMMA是一種標(biāo)準(zhǔn)的高溶解度聚合物反蝕劑，最適合大小10納米；比PMMA溶解度大得多的無機(jī)試劑有：金屬鹵化物，金屬氧化物，以及半導(dǎo)體氧化物——因?yàn)樗麄兡軌虺惺?-5納米的電子輻射反響AnecessaryprocesstotransfertheEBL-madepatternfromtheresistontotheunderlyingsubstrateTwobasicpatterntransfermethods?Additiveprocess:addinganewmaterialtothesurfaceofthe substrate,wheretheresisthasbeenremovedthroughthepatterningprocess;includingLift-offprocessandPlatingprocess?Subtractiveprocess:removingsomematerialsfromsubstrateselectivelyonlyintheareaswheretheresisthasbeenremoved2-1-3PatternTransferProcess圖案轉(zhuǎn)移過程將EBL制作的圖案從反蝕劑轉(zhuǎn)移到下面襯底的必要過程；倆種根本的轉(zhuǎn)移方式：1、添加方式：在通過圖案形成過程已經(jīng)出去反蝕劑的襯底外表加一種新材料；包括剝離法和電鍍法；2、抽離方式：去掉襯底已除去反蝕劑區(qū)域局部的材料TheLift-offprocessflowAnundercutprofileinPMMAresistTheElectroplatingProcessflowSubtractivePatternTransferProcessAdvantagesofX-rayenergysourceandXRL?Greatpenetratingpower?Scatteringfreeproperty?Withveryhighresolutionwhileeliminatingdepthoffocus,reflection,andscatteringproblems?Withprecisefeaturesizeandbetteredgecontrol?Beindependentofpatterngeometry,substratetopography,andsubstratereflectivityDifferencesbetweenXRLandotherlithography?Sources(synchrotronradiationandlaserplasma)?Masks?resists2-2X-rayLithography(XRL)X射線刻蝕X射線能量來源和X射線刻蝕的優(yōu)點(diǎn)：1、強(qiáng)大的穿透能；2、自由散射性能；3、在消除聚焦，反射，散射問題深度的同時(shí)有很高的分辨率4、準(zhǔn)確的大小參數(shù)和邊緣控制;5、與圖案形狀、襯底形狀和襯底反射率無關(guān)X射線刻蝕與其他刻蝕的區(qū)別：1源〔同步加速輻射和激光等離子體〕；2、面具；3、反蝕劑TypicalschematicdiagramsofXRLsystem(1)UtilizingapointX-raysourceTypicalschematicdiagramsofXRLsystem(2)ASynchrotron-basedXRLsystemMaskFabrication:themostdifficultchallengeofXRLMesa-臺(tái)面；pyrex-硼硅酸玻璃；attenuation-衰減AgoldadditiveprocessforX-raymaskfabricationResistrequirement〔反蝕劑要求〕?Highsensitivitytoionizingradiation〔對(duì)離子輻射強(qiáng)烈敏感〕?Goodetchresistancei