Thaum ntxov ntub etching txhawb txoj kev txhim kho ntawm kev ntxuav lossis ashing txheej txheem. Niaj hnub no, qhuav etching siv plasma tau dhau los ua qhov tseem ceebtxheej txheem etching. Plasma muaj cov electrons, cations thiab radicals. Lub zog siv rau lub plasma ua rau cov hluav taws xob sab nraud ntawm cov pa roj hauv lub xeev nruab nrab raug tshem tawm, yog li hloov cov electrons rau hauv cations.
Tsis tas li ntawd, cov atoms tsis zoo hauv cov molecules tuaj yeem raug tshem tawm los ntawm kev siv lub zog los tsim hluav taws xob tsis zoo radicals. Qhuav etching siv cations thiab radicals uas tsim cov ntshav, qhov twg cations yog anisotropic (tsim rau etching nyob rau hauv ib qho kev taw qhia) thiab radicals yog isotropic (tsim rau etching nyob rau hauv tag nrho cov lus qhia). Tus naj npawb ntawm cov radicals ntau dua li cov cations. Hauv qhov no, qhuav etching yuav tsum yog isotropic zoo li ntub etching.
Txawm li cas los xij, nws yog anisotropic etching ntawm qhuav etching uas ua rau ultra-miniaturized circuits tau. Qhov no yog vim li cas? Tsis tas li ntawd, qhov etching ceev ntawm cations thiab radicals qeeb heev. Yog li cas peb tuaj yeem siv plasma etching txoj hauv kev rau cov khoom loj hauv lub ntsej muag ntawm qhov tsis txaus no?
1. Qhov ratio (A/R)
Daim duab 1. Lub tswv yim ntawm nam piv thiab qhov cuam tshuam ntawm kev kawm txuj ci rau nws
Aspect Ratio yog qhov piv ntawm kab rov tav dav rau ntsug qhov siab (piv txwv li, qhov siab muab faib los ntawm qhov dav). Qhov me me ntawm qhov tseem ceeb (CD) ntawm lub voj voog, qhov loj dua qhov sib piv tus nqi. Ntawd yog, piv txwv li tus nqi piv txwv ntawm 10 thiab qhov dav ntawm 10nm, qhov siab ntawm lub qhov drilled thaum lub sij hawm etching yuav tsum yog 100nm. Yog li ntawd, rau cov khoom tiam tom ntej uas yuav tsum tau ultra-miniaturization (2D) los yog siab ceev (3D), tsis tshua muaj siab nam piv qhov tseem ceeb yuav tsum tau xyuas kom meej tias cations tuaj yeem nkag mus rau hauv qab zaj duab xis thaum etching.
Txhawm rau ua tiav cov thev naus laus zis ultra-miniaturization nrog qhov tseem ceeb ntawm qhov tsawg dua 10nm hauv 2D cov khoom lag luam, lub capacitor nam piv tus nqi ntawm dynamic random access memory (DRAM) yuav tsum tau khaws cia siab tshaj 100. Ib yam li ntawd, 3D NAND flash nco kuj yuav tsum muaj qhov sib piv ntau dua. mus stack 256 txheej los yog ntau tshaj ntawm cell stacking txheej. Txawm hais tias cov xwm txheej xav tau rau lwm cov txheej txheem tau ua tiav, cov khoom tsim nyog yuav tsis tuaj yeem tsim tau yog tias covtxheej txheem etchingtsis yog raws li tus qauv. Qhov no yog vim li cas etching tshuab tau dhau los ua qhov tseem ceeb.
2. Txheej txheem cej luam ntawm 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 ntawm cov yeeb nkab txoj kab uas hla, qhov yooj yim dua rau cov kua nkag, uas yog hu ua capillary phenomenon. Txawm li cas los xij, yog tias lub qhov (kaw kawg) yuav tsum tau drilled nyob rau hauv qhov chaw raug, qhov kev nkag ntawm cov kua yuav nyuaj heev. Yog li ntawd, txij li qhov tseem ceeb ntawm lub Circuit Court yog 3um rau 5um nyob rau hauv nruab nrab-1970s, qhuav.etchingtau maj mam hloov ntub etching raws li lub ntsiab. Ntawd yog, txawm hais tias ionized, nws yooj yim dua rau nkag mus rau qhov sib sib zog nqus vim tias qhov ntim ntawm ib qho molecule me dua li ntawm cov organic polymer tov molecule.
Thaum lub sij hawm plasma etching, lub sab hauv ntawm lub chamber uas siv rau etching yuav tsum tau hloov mus rau lub nqus tsev vacuum ua ntej txhaj cov plasma qhov chaw gas haum rau cov txheej txheem. Thaum etching khoom oxide zaj duab xis, yuav tsum tau siv cov pa roj carbon fluoride uas muaj zog dua. Rau cov yeeb yaj kiab silicon lossis hlau tsis muaj zog, chlorine-based plasma gases yuav tsum tau siv.
Yog li, yuav ua li cas lub rooj vag txheej thiab lub hauv paus silicon dioxide (SiO2) insulating txheej yuav tsum tau etched?
Ua ntej, rau lub rooj vag txheej, silicon yuav tsum tau muab tshem tawm siv chlorine-raws li ntshav (silicon + chlorine) nrog polysilicon etching selectivity. Rau hauv qab txheej insulating, silicon dioxide zaj duab xis yuav tsum tau etched nyob rau hauv ob kauj ruam siv cov pa roj carbon fluoride-raws li plasma qhov chaw roj (silicon dioxide + carbon tetrafluoride) uas muaj zog etching xaiv thiab ua tau zoo.
3. Reactive ion etching (RIE lossis physicochemical etching) txheej txheem
Daim duab 3. Qhov zoo ntawm reactive ion etching (anisotropy thiab siab etching tus nqi)
Plasma muaj ob qho tib si isotropic dawb radicals thiab anisotropic cations, yog li nws ua li cas anisotropic etching?
Plasma qhuav etching feem ntau yog ua los ntawm reactive ion etching (RIE, Reactive Ion Etching) los yog daim ntaub ntawv raws li txoj kev no. Lub hauv paus ntawm txoj kev RIE yog ua kom tsis muaj zog ntawm kev sib txuas ntawm lub hom phiaj molecules hauv zaj duab xis los ntawm kev tawm tsam thaj tsam etching nrog anisotropic cations. Qhov chaw tsis muaj zog yog absorbed los ntawm cov dawb radicals, ua ke nrog cov khoom uas ua rau cov txheej txheem, hloov mus rau hauv cov pa roj (ib qho chaw tsis muaj zog) thiab tso tawm.
Txawm hais tias cov dawb radicals muaj cov yam ntxwv ntawm isotropic, cov molecules uas ua rau hauv qab ntawm qhov chaw (uas yog lub zog khi tsis muaj zog los ntawm kev tawm tsam ntawm cations) tau yooj yim dua los ntawm cov dawb radicals thiab hloov mus rau hauv cov tebchaw tshiab dua li cov phab ntsa uas muaj zog binding. Yog li ntawd, downward etching ua lub ntsiab. Cov khoom ntes tau los ua cov pa nrog cov dawb radicals, uas yog desorbed thiab tso tawm ntawm qhov chaw nyob rau hauv qhov kev txiav txim ntawm lub tshuab nqus tsev.
Lub sijhawm no, cov cations tau txais los ntawm lub cev ua haujlwm thiab cov dawb radicals tau los ntawm kev ua tshuaj lom neeg yog ua ke rau lub cev thiab tshuaj etching, thiab tus nqi etching (Etch Rate, degree ntawm etching nyob rau hauv ib lub sij hawm ntawm lub sij hawm) yog nce los ntawm 10 npaug. piv nrog cov ntaub ntawv ntawm cationic etching los yog dawb radical etching ib leeg. Txoj kev no tuaj yeem tsis tsuas yog nce tus nqi etching ntawm anisotropic downward etching, tab sis kuj daws qhov teeb meem ntawm polymer residue tom qab etching. Txoj kev no hu ua reactive ion etching (RIE). Tus yuam sij rau txoj kev vam meej ntawm RIE etching yog nrhiav cov roj plasma uas haum rau etching zaj duab xis. Nco tseg: Plasma etching yog RIE etching, thiab ob qho tib si tuaj yeem suav tias yog tib lub tswv yim.
4. Ech Rate thiab Core Performance Index
Daim duab 4. Core Etch Performance Index ntsig txog Etch Rate
Ech rate yog hais txog qhov tob ntawm zaj duab xis uas xav kom ncav cuag hauv ib feeb. Yog li nws txhais li cas tias tus nqi etch txawv ntawm ib feem mus rau ib feem ntawm ib qho wafer?
Qhov no txhais tau hais tias qhov tob etch txawv ntawm ib feem mus rau ib feem ntawm lub wafer. Vim li no, nws yog ib qho tseem ceeb heev los teeb tsa qhov kawg taw tes (EOP) qhov twg etching yuav tsum nres los ntawm kev xav txog qhov nruab nrab etch tus nqi thiab etch qhov tob. Txawm hais tias EOP tau teeb tsa, tseem muaj qee qhov chaw uas qhov etch qhov tob tob (dhau-etched) lossis ntiav (hauv qab-etched) dua li qhov tau npaj tseg. Txawm li cas los xij, hauv qab-etching ua rau muaj kev puas tsuaj ntau dua li kev etching thaum etching. Vim hais tias nyob rau hauv cov ntaub ntawv ntawm under-etching, qhov under-etched ib feem yuav cuam tshuam cov txheej txheem tom ntej xws li ion implantation.
Meanwhile, selectivity ( ntsuas los ntawm etch tus nqi) yog ib qho tseem ceeb ntawm kev ua tau zoo ntawm cov txheej txheem etching. Cov txheej txheem ntsuas yog raws li kev sib piv ntawm qhov sib piv ntawm qhov etch ntawm lub npog ntsej muag (photoresist zaj duab xis, oxide zaj duab xis, silicon nitride zaj duab xis, thiab lwm yam) thiab lub hom phiaj txheej. Qhov no txhais tau hais tias qhov siab dua qhov kev xaiv, qhov ceev ntawm lub hom phiaj txheej yog etched. Qhov siab dua qib ntawm miniaturization, qhov siab dua qhov yuav tsum tau xaiv yog los xyuas kom meej tias cov qauv zoo tuaj yeem nthuav tawm zoo kawg nkaus. Txij li cov kev taw qhia etching yog ncaj, qhov kev xaiv ntawm cationic etching yog tsawg, thaum lub selectivity ntawm radical etching yog siab, uas txhim kho cov selectivity ntawm RIE.
5. txheej txheem etching
Daim duab 5. Etching txheej txheem
Ua ntej, lub wafer tau muab tso rau hauv lub qhov cub oxidation nrog qhov kub thiab txias ntawm 800 thiab 1000 ℃, thiab tom qab ntawd ib zaj duab xis silicon dioxide (SiO2) nrog cov khoom siv hluav taws xob siab yog tsim rau saum npoo ntawm wafer los ntawm txoj kev qhuav. Tom ntej no, cov txheej txheem tso tawm tau nkag mus rau hauv cov txheej txheem silicon lossis txheej txheej txheej txheej ntawm oxide zaj duab xis los ntawm cov tshuaj vapor deposition (CVD) / lub cev vapor deposition (PVD). Yog tias cov txheej txheem silicon raug tsim, cov txheej txheem impurity diffusion tuaj yeem ua tau kom nce conductivity yog tias tsim nyog. Thaum lub sij hawm impurity diffusion txheej txheem, ntau impurities yog feem ntau ntxiv dua.
Lub sijhawm no, txheej txheej insulating thiab txheej polysilicon yuav tsum tau ua ke rau etching. Ua ntej, siv photoresist. Tom qab ntawd, lub npog ntsej muag tau muab tso rau ntawm cov yeeb yaj kiab photoresist thiab cov dej ntub dej yog ua los ntawm kev immersion rau imprint cov qauv uas xav tau (tsis pom qhov muag liab qab) ntawm cov yeeb yaj kiab photoresist. Thaum cov qauv txheej txheem tau nthuav tawm los ntawm kev txhim kho, lub photoresist hauv thaj chaw photosensitive raug tshem tawm. Tom qab ntawd, lub wafer ua tiav los ntawm cov txheej txheem photolithography yog pauv mus rau txheej txheem etching rau qhuav etching.
Qhuav etching feem ntau yog ua los ntawm reactive ion etching (RIE), nyob rau hauv uas etching yog rov ua dua los ntawm kev hloov cov pa roj uas haum rau txhua zaj duab xis. Ob qho tib si qhuav etching thiab ntub etching aim kom nce qhov sib piv (A / R tus nqi) ntawm etching. Tsis tas li ntawd, kev tu tsis tu ncua yuav tsum tau tshem tawm cov polymer uas muaj nyob rau hauv qab ntawm lub qhov (qhov sib txawv tsim los ntawm etching). Lub ntsiab lus tseem ceeb yog tias txhua qhov sib txawv (xws li cov khoom siv, cov khoom siv roj, lub sijhawm, daim ntawv thiab qhov sib lawv liag) yuav tsum tau kho cov organically kom ntseeg tau tias cov tshuaj ntxuav lossis cov roj plasma tuaj yeem ntws mus rau hauv qab ntawm lub trench. Ib qho kev hloov me ntsis hauv qhov sib txawv yuav tsum tau muab xam los ntawm lwm qhov sib txawv, thiab cov txheej txheem kev suav rov qab no rov qab mus txog thaum nws ua tau raws li lub hom phiaj ntawm txhua theem. Tsis ntev los no, cov txheej txheem monoatomic xws li atomic layer deposition (ALD) txheej tau dhau los ua nyias thiab nyuaj. Yog li ntawd, etching tshuab yog txav mus rau kev siv qhov kub thiab txias. Cov txheej txheem etching lub hom phiaj los tswj qhov tseem ceeb ntawm qhov loj me (CD) los 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 nyob rau hauv-etching thiab cov teeb meem cuam tshuam txog kev tshem tawm cov khoom seem. Ob kab lus saum toj no ntawm etching lub hom phiaj los muab cov neeg nyeem nkag siab txog lub hom phiaj ntawm cov txheej txheem etching, cov teeb meem kom ua tiav cov hom phiaj saum toj no, thiab cov ntsuas kev ua tau zoo siv los kov yeej cov teeb meem no.
Post lub sij hawm: Sep-10-2024