Kev siv cov txheej txheem ntub dej thaum ntxov tau txhawb nqa kev txhim kho cov txheej txheem ntxuav lossis tshauv. Niaj hnub no, kev siv cov txheej txheem qhuav siv plasma tau dhau los ua qhov tseem ceebcov txheej txheem etchingCov plasma muaj cov electrons, cations thiab radicals. Lub zog siv rau cov plasma ua rau cov electrons sab nraud ntawm cov roj qhov chaw nyob rau hauv lub xeev tsis muaj zog raug tshem tawm, yog li hloov cov electrons no mus rau hauv cations.
Ntxiv mus, cov atoms tsis zoo hauv cov molecule tuaj yeem raug tshem tawm los ntawm kev siv lub zog los tsim cov radicals tsis muaj hluav taws xob. Kev etching qhuav siv cov cations thiab radicals uas ua rau plasma, qhov twg cations yog anisotropic (haum rau etching hauv ib qho kev taw qhia) thiab radicals yog isotropic (haum rau etching hauv txhua qhov kev taw qhia). Tus lej ntawm cov radicals yog ntau dua li tus lej ntawm cations. Hauv qhov no, kev etching qhuav yuav tsum yog isotropic zoo li kev etching ntub.
Txawm li cas los xij, nws yog qhov anisotropic etching ntawm qhuav etching uas ua rau ultra-miniaturized circuits ua tau. Vim li cas rau qhov no yog dab tsi? Tsis tas li ntawd, qhov ceev etching ntawm cations thiab radicals qeeb heev. Yog li peb tuaj yeem siv cov txheej txheem plasma etching rau kev tsim khoom loj li cas hauv qhov tsis zoo no?
1. Qhov Sib Piv (A/R)
Daim Duab 1. Lub tswv yim ntawm qhov sib piv thiab qhov cuam tshuam ntawm kev nce qib ntawm thev naus laus zis rau nws
Qhov Sib Piv ntawm Qhov Sib Piv yog qhov sib piv ntawm qhov dav kab rov tav rau qhov siab ntsug (piv txwv li, qhov siab faib los ntawm qhov dav). Qhov me dua qhov tseem ceeb ntawm qhov ntev (CD) ntawm lub voj voog, qhov loj dua qhov sib piv ntawm qhov sib piv. Ntawd yog, xav tias qhov sib piv ntawm qhov sib piv ntawm 10 thiab qhov dav ntawm 10nm, qhov siab ntawm qhov uas tau khawb thaum lub sijhawm etching yuav tsum yog 100nm. Yog li ntawd, rau cov khoom lag luam tiam tom ntej uas xav tau ultra-miniaturization (2D) lossis high density (3D), qhov sib piv ntawm qhov sib piv siab heev yuav tsum tau ua kom ntseeg tau tias cov cations tuaj yeem nkag mus rau hauv zaj duab xis hauv qab thaum lub sijhawm etching.
Yuav kom ua tiav cov thev naus laus zis ultra-miniaturization nrog qhov tseem ceeb ntawm tsawg dua 10nm hauv 2D cov khoom, qhov sib piv ntawm lub capacitor ntawm dynamic random access memory (DRAM) yuav tsum tau khaws cia saum toj no 100. Ib yam li ntawd, 3D NAND flash memory kuj xav tau qhov sib piv siab dua los sib sau ua ke 256 txheej lossis ntau dua ntawm cov txheej txheem sib sau ua ke. Txawm tias cov xwm txheej xav tau rau lwm cov txheej txheem tau ntsib, cov khoom xav tau tsis tuaj yeem tsim tau yog tiascov txheej txheem etchingtsis yog raws li tus qauv. Qhov no yog vim li cas cov thev naus laus zis etching thiaj li tseem ceeb zuj zus.
2. Kev piav qhia txog plasma etching
Daim Duab 2. Kev txiav txim siab cov roj plasma raws li hom zaj duab xis
Thaum siv cov yeeb nkab hollow, qhov nqaim dua ntawm cov yeeb nkab txoj kab uas hla, qhov yooj yim dua rau cov kua nkag mus, uas yog qhov hu ua capillary phenomenon. Txawm li cas los xij, yog tias yuav tsum tau tho qhov (kawg kawg) hauv thaj chaw raug, qhov nkag ntawm cov kua yuav nyuaj heev. Yog li ntawd, txij li qhov loj me tseem ceeb ntawm lub voj voog yog 3um txog 5um thaum nruab nrab xyoo 1970, qhuavkev txiavtau maj mam hloov qhov ntub dej etching ua lub hauv paus tseem ceeb. Qhov ntawd yog, txawm hais tias ionized, nws yooj yim dua rau kev nkag mus rau hauv qhov tob vim tias qhov ntim ntawm ib lub molecule yog me dua li ntawm cov organic polymer solution molecule.
Thaum lub sijhawm plasma etching, sab hauv ntawm lub chamber ua haujlwm siv rau etching yuav tsum tau kho kom haum rau lub xeev nqus tsev ua ntej txhaj cov roj plasma uas haum rau txheej cuam tshuam. Thaum etching cov yeeb yaj kiab oxide khov kho, yuav tsum siv cov pa roj carbon fluoride uas muaj zog dua. Rau cov yeeb yaj kiab silicon lossis hlau uas tsis muaj zog, yuav tsum siv cov pa roj plasma uas muaj chlorine.
Yog li, yuav tsum ua li cas thiaj li kos tau lub rooj vag txheej thiab lub hauv qab silicon dioxide (SiO2) insulating txheej?
Ua ntej, rau lub rooj vag txheej, silicon yuav tsum tau tshem tawm siv cov chlorine-based plasma (silicon + chlorine) nrog polysilicon etching selectivity. Rau cov txheej insulating hauv qab, cov yeeb yaj kiab silicon dioxide yuav tsum tau etched hauv ob kauj ruam siv cov pa roj carbon fluoride-based plasma (silicon dioxide + carbon tetrafluoride) nrog cov etching selectivity thiab ua haujlwm tau zoo dua.
3. Cov txheej txheem reactive ion etching (RIE lossis physicochemical etching)
Daim Duab 3. Cov txiaj ntsig ntawm kev kho cov tshuaj reactive ion etching (anisotropy thiab high etching rate)
Plasma muaj ob qho tib si isotropic free radicals thiab anisotropic cations, yog li nws ua li cas anisotropic etching?
Kev siv plasma qhuav etching feem ntau yog ua los ntawm kev siv reactive ion etching (RIE, Reactive Ion Etching) lossis cov ntawv thov raws li txoj kev no. Lub hauv paus ntawm txoj kev RIE yog ua kom lub zog khi ntawm cov molecule hauv zaj duab xis tsis muaj zog los ntawm kev tawm tsam thaj chaw etching nrog cov cations anisotropic. Thaj chaw tsis muaj zog raug nqus los ntawm cov dawb radicals, ua ke nrog cov khoom me me uas ua rau txheej, hloov mus ua roj (ib qho khoom sib xyaw ua ke) thiab tso tawm.
Txawm hais tias cov free radicals muaj cov yam ntxwv isotropic, cov molecules uas ua rau hauv qab (uas lub zog khi tsis muaj zog los ntawm kev tawm tsam ntawm cations) yooj yim dua los ntawm cov free radicals thiab hloov mus rau hauv cov tshuaj tshiab dua li cov phab ntsa sab nrog lub zog khi muaj zog. Yog li ntawd, downward etching dhau los ua lub hauv paus tseem ceeb. Cov khoom me me uas ntes tau dhau los ua roj nrog cov free radicals, uas raug desorbed thiab tso tawm ntawm qhov chaw nyob rau hauv qhov kev ua ntawm lub tshuab nqus tsev.
Lub sijhawm no, cov cations tau los ntawm kev ua haujlwm lub cev thiab cov dawb radicals tau los ntawm kev ua haujlwm tshuaj lom neeg tau ua ke rau kev siv lub cev thiab tshuaj lom neeg, thiab tus nqi etching (Etch Rate, qib ntawm etching hauv ib lub sijhawm) tau nce 10 npaug piv rau cov ntaub ntawv ntawm cationic etching lossis dawb radical etching ib leeg. Txoj kev no tsis tsuas yog ua rau tus nqi etching ntawm anisotropic downward etching nce ntxiv, tab sis kuj daws qhov teeb meem ntawm cov polymer residue tom qab etching. Txoj kev no hu ua reactive ion etching (RIE). Tus yuam sij rau kev vam meej ntawm RIE etching yog nrhiav cov roj plasma uas tsim nyog rau etching zaj duab xis. Nco ntsoov: Plasma etching yog RIE etching, thiab ob qho tib si tuaj yeem suav tias yog tib lub tswv yim.
4. Tus nqi Etch thiab Core Performance Index
Daim Duab 4. Cov Ntawv Qhia Txog Kev Ua Haujlwm ntawm Core Etch uas cuam tshuam nrog Etch Rate
Tus nqi ntawm kev txhuam yog hais txog qhov tob ntawm zaj duab xis uas xav tias yuav ncav cuag hauv ib feeb. Yog li ntawd, nws txhais li cas tias tus nqi txhuam sib txawv ntawm ib feem mus rau ib feem ntawm ib lub wafer?
Qhov no txhais tau tias qhov tob ntawm etch sib txawv ntawm ib feem mus rau ib feem ntawm lub wafer. Vim li no, nws yog ib qho tseem ceeb heev uas yuav tsum teeb tsa qhov kawg (EOP) qhov twg etching yuav tsum nres los ntawm kev xav txog qhov nruab nrab etch tus nqi thiab etch qhov tob. Txawm tias EOP tau teeb tsa, tseem muaj qee qhov chaw uas qhov tob ntawm etch tob dua (dhau-etched) lossis ntiav dua (tsis-etched) dua li qhov tau npaj tseg thawj zaug. Txawm li cas los xij, under-etched ua rau muaj kev puas tsuaj ntau dua li over-etching thaum lub sijhawm etching. Vim tias nyob rau hauv cov ntaub ntawv ntawm under-etching, qhov under-etched yuav cuam tshuam cov txheej txheem tom ntej xws li ion implantation.
Lub caij no, kev xaiv (ntsuas los ntawm tus nqi etch) yog qhov qhia txog kev ua tau zoo tseem ceeb ntawm cov txheej txheem etching. Tus qauv ntsuas yog raws li kev sib piv ntawm tus nqi etch ntawm txheej npog ntsej muag (photoresist zaj duab xis, oxide zaj duab xis, silicon nitride zaj duab xis, thiab lwm yam) thiab txheej phiaj. Qhov no txhais tau tias qhov siab dua qhov kev xaiv, qhov ceev dua lub hom phiaj txheej yog etched. Qhov siab dua qib ntawm miniaturization, qhov siab dua qhov kev xaiv yuav tsum tau ua kom ntseeg tau tias cov qauv zoo tuaj yeem nthuav tawm zoo meej. Txij li thaum qhov kev taw qhia etching yog ncaj, qhov kev xaiv ntawm cationic etching yog qis, thaum qhov kev xaiv ntawm radical etching yog siab, uas txhim kho qhov kev xaiv ntawm RIE.
5. Cov txheej txheem etching
Daim Duab 5. Cov txheej txheem etching
Ua ntej, lub wafer raug muab tso rau hauv lub cub tawg oxidation nrog qhov kub thiab txias tswj ntawm 800 thiab 1000 ℃, thiab tom qab ntawd ib zaj duab xis silicon dioxide (SiO2) nrog cov khoom rwb thaiv tsev siab tau tsim rau ntawm qhov chaw ntawm lub wafer los ntawm txoj kev qhuav. Tom ntej no, cov txheej txheem deposition raug nkag mus rau hauv los tsim ib txheej silicon lossis ib txheej conductive ntawm zaj duab xis oxide los ntawm kev tso pa tshuaj lom neeg (CVD) / lub cev vapor deposition (PVD). Yog tias ib txheej silicon raug tsim, ib qho txheej txheem impurity diffusion tuaj yeem ua tiav kom nce conductivity yog tias tsim nyog. Thaum lub sijhawm txheej txheem impurity diffusion, ntau yam impurities feem ntau raug ntxiv dua.
Lub sijhawm no, cov txheej insulating thiab cov txheej polysilicon yuav tsum tau ua ke rau kev etching. Ua ntej, siv photoresist. Tom qab ntawd, lub npog ntsej muag raug muab tso rau ntawm zaj duab xis photoresist thiab kev ntub dej raug ua los ntawm kev immersion kom luam tawm cov qauv xav tau (tsis pom rau lub qhov muag liab qab) ntawm zaj duab xis photoresist. Thaum cov qauv qhia los ntawm kev txhim kho, cov photoresist hauv thaj chaw photosensitive raug tshem tawm. Tom qab ntawd, cov wafer ua los ntawm cov txheej txheem photolithography raug xa mus rau cov txheej txheem etching rau kev etching qhuav.
Kev etching qhuav feem ntau yog ua los ntawm kev siv tshuaj reactive ion etching (RIE), uas kev etching rov ua dua feem ntau los ntawm kev hloov cov roj qhov chaw uas haum rau txhua zaj duab xis. Ob qho tib si etching qhuav thiab etching ntub dej tsom mus rau kev nce qhov sib piv (A / R tus nqi) ntawm etching. Tsis tas li ntawd, kev ntxuav tas li yog qhov yuav tsum tau tshem tawm cov polymer sau rau hauv qab ntawm lub qhov (qhov sib txawv tsim los ntawm etching). Lub ntsiab lus tseem ceeb yog tias txhua yam hloov pauv (xws li cov ntaub ntawv, cov roj qhov chaw, lub sijhawm, daim ntawv thiab kab lus) yuav tsum tau kho kom zoo kom ntseeg tau tias cov tshuaj ntxuav lossis cov roj plasma tuaj yeem ntws mus rau hauv qab ntawm qhov av. Kev hloov pauv me ntsis hauv qhov hloov pauv yuav tsum tau rov suav dua ntawm lwm yam hloov pauv, thiab cov txheej txheem rov suav dua no rov ua dua kom txog thaum nws ua tiav lub hom phiaj ntawm txhua theem. Tsis ntev los no, cov txheej monoatomic xws li cov txheej atomic deposition (ALD) tau dhau los ua nyias dua thiab nyuaj dua. Yog li ntawd, cov thev naus laus zis etching tab tom txav mus rau kev siv qhov kub thiab txias qis thiab siab. Cov txheej txheem etching lub hom phiaj yog tswj qhov tseem ceeb (CD) kom tsim cov qauv zoo thiab xyuas kom meej tias cov teeb meem tshwm sim los ntawm cov txheej txheem etching raug zam, tshwj xeeb tshaj yog under-etching thiab teeb meem cuam tshuam nrog kev tshem tawm cov khoom seem. Ob tsab xov xwm saum toj no ntawm etching lub hom phiaj yog muab rau cov nyeem ntawv nrog kev nkag siab txog lub hom phiaj ntawm cov txheej txheem etching, cov teeb meem rau kev ua tiav cov hom phiaj saum toj no, thiab cov ntsuas kev ua tau zoo siv los kov yeej cov teeb meem no.
Lub sijhawm tshaj tawm: Cuaj hlis-10-2024