Kuyika konyowa koyambirira kumalimbikitsa chitukuko cha kuyeretsa kapena phulusa. Masiku ano, kuyanika kowuma pogwiritsa ntchito plasma kwakhala kofalaetching process. Plasma imakhala ndi ma elekitironi, ma cations ndi ma radicals. Mphamvu yogwiritsidwa ntchito ku plasma imapangitsa kuti ma elekitironi akunja a gasi omwe salowerera ndale achotsedwe, motero amatembenuza ma electron kukhala ma cations.
Kuphatikiza apo, maatomu opanda ungwiro m'mamolekyu amatha kuchotsedwa pogwiritsa ntchito mphamvu kuti apange ma radicals osalowererapo pamagetsi. Dry etching imagwiritsa ntchito ma cations ndi ma radicals omwe amapanga plasma, pomwe ma cations ndi anisotropic (oyenera kumangirira mbali ina) ndipo ma radicals ndi isotropic (oyenera kuyika mbali zonse). Chiwerengero cha ma radicals ndi chachikulu kwambiri kuposa kuchuluka kwa ma cations. Pachifukwa ichi, kuyanika kowuma kuyenera kukhala isotropic ngati kunyowa konyowa.
Komabe, ndi anisotropic etching of dry etching yomwe imapangitsa mabwalo a Ultra-miniaturized kukhala zotheka. Chifukwa chiyani? Kuphatikiza apo, kuthamanga kwa ma cations ndi ma radicals ndikochepa kwambiri. Ndiye tingagwiritse ntchito bwanji njira zopangira plasma popanga anthu ambiri pomwe tili ndi vuto ili?
1. Chigawo (A/R)
Chithunzi 1. Lingaliro la chiŵerengero cha gawo ndi zotsatira za kupita patsogolo kwaukadaulo pa izo
Aspect Ratio ndi chiyerekezo cha m'lifupi mwake chopingasa ndi utali wolunjika (ie, kutalika kugawidwa ndi m'lifupi). Kuchepa kwa gawo lofunikira (CD) la dera, ndikokulirapo kwa chiyerekezo cha mtengo. Ndiko kuti, potengera chiyerekezo cha 10 ndi m'lifupi mwake 10nm, kutalika kwa dzenje lobowoleredwa panthawi yolumikizira kuyenera kukhala 100nm. Chifukwa chake, pazogulitsa zam'badwo wotsatira zomwe zimafunikira ultra-miniaturization (2D) kapena kachulukidwe kwambiri (3D), ziwopsezo zapamwamba kwambiri zimafunikira kuwonetsetsa kuti ma cation amatha kulowa mufilimu yapansi panthawi yolowera.
Kuti mukwaniritse ukadaulo wa Ultra-miniaturization wokhala ndi gawo lofunikira lochepera 10nm muzinthu za 2D, kuchuluka kwa capacitor gawo la dynamic random access memory (DRAM) kuyenera kusungidwa pamwamba pa 100. kuti muwunjike zigawo 256 kapena kuposerapo kwa ma cell stacking layers. Ngakhale zikhalidwe zofunika panjira zina zikwaniritsidwa, zinthu zofunika sizingapangidwe ngatietching processsizili mulingo. Ichi ndichifukwa chake teknoloji ya etching ikukhala yofunika kwambiri.
2. Chidule cha plasma etching
Chithunzi 2. Kuzindikira gwero la mpweya wa plasma malinga ndi mtundu wa filimu
Pamene chitoliro chopanda kanthu chikugwiritsidwa ntchito, kucheperachepera kwa chitolirocho, kumakhala kosavuta kuti madzi alowe, chomwe chimatchedwa capillary phenomenon. Komabe, ngati dzenje (lotsekedwa kumapeto) liyenera kubowoleredwa pamalo owonekera, kulowetsa kwamadzimadzi kumakhala kovuta. Chifukwa chake, popeza kukula kofunikira kwa dera kunali 3um mpaka 5um pakati pa zaka za m'ma 1970, youma.etchingwasintha pang'onopang'ono etching yonyowa ngati mainstream. Ndiko kuti, ngakhale ionized, ndikosavuta kulowa m'mabowo akuya chifukwa kuchuluka kwa molekyulu imodzi ndi yaying'ono kuposa molekyulu ya organic polymer solution.
Pa etching ya plasma, mkati mwa chipinda chopangiramo chomwe chimagwiritsidwa ntchito popangira etching chiyenera kusinthidwa kukhala malo opanda mpweya musanayike mpweya woyambira wa plasma woyenera wosanjikiza wofunikira. Mukayika mafilimu olimba a oxide, mipweya yamphamvu yochokera ku carbon fluoride iyenera kugwiritsidwa ntchito. Kwa mafilimu ofooka a silicon kapena zitsulo, mpweya wochokera ku plasma wa chlorine uyenera kugwiritsidwa ntchito.
Ndiye, kodi wosanjikiza pachipata ndi silicon dioxide (SiO2) insulating layer iyenera kukhazikitsidwa bwanji?
Choyamba, pachipata, silicon iyenera kuchotsedwa pogwiritsa ntchito plasma yochokera ku chlorine (silicon + chlorine) yokhala ndi polysilicon etching selectivity. Kwa wosanjikiza wapansi, filimu ya silicon dioxide iyenera kuzikika mu magawo awiri pogwiritsa ntchito mpweya wa plasma wopangidwa ndi mpweya wa fluoride (silicon dioxide + carbon tetrafluoride) yokhala ndi kusankha kwamphamvu komanso kuchita bwino.
3. Njira yowonongeka ya ion etching (RIE kapena physicochemical etching).
Chithunzi 3. Ubwino wa reactive ion etching (anisotropy ndi high etching rate)
Plasma imakhala ndi ma isotropic free radicals ndi ma anisotropic cations, ndiye imachita bwanji etching ya anisotropic?
Etching youma ya plasma imachitika makamaka ndi reactive ion etching (RIE, Reactive Ion Etching) kapena kugwiritsa ntchito njira iyi. Pakatikati pa njira ya RIE ndikufooketsa mphamvu yomangirira pakati pa mamolekyu omwe amawatsata mufilimuyo powononga malo ozungulira ndi ma anisotropic cations. Malo ofooka amatengedwa ndi ma radicals aulere, ophatikizidwa ndi tinthu tating'onoting'ono tomwe timapanga wosanjikiza, amasinthidwa kukhala gasi (gawo losakhazikika) ndikumasulidwa.
Ngakhale ma radicals aulere ali ndi mawonekedwe a isotropic, mamolekyu omwe amapanga pansi (omwe mphamvu yake yomangiriza imafooka chifukwa cha kuukira kwa ma cations) amagwidwa mosavuta ndi ma radicals aulere ndikusinthidwa kukhala zinthu zatsopano kuposa makoma am'mbali okhala ndi mphamvu zomangira zolimba. Chifukwa chake, kutsika kwapansi kumakhala kofala. The anagwidwa particles kukhala mpweya ndi ma free radicals, amene desorbed ndi kumasulidwa padziko pansi pa zochita za vacuum.
Panthawiyi, ma cations omwe amapezedwa ndi machitidwe a thupi ndi ma radicals aulere omwe amapezedwa ndi mankhwala amaphatikizidwa kuti agwirizane ndi thupi ndi mankhwala, ndipo mlingo wa etching (Etch Rate, mlingo wa etching mu nthawi inayake) umawonjezeka ndi 10 nthawi. poyerekeza ndi nkhani ya cationic etching kapena free radical etching yokha. Njira imeneyi si kuonjezera etching mlingo wa anisotropic pansi etching, komanso kuthetsa vuto la zotsalira polima pambuyo etching. Njirayi imatchedwa reactive ion etching (RIE). Chinsinsi cha kupambana kwa RIE etching ndikupeza mpweya woyambira wa plasma woyenera kuyika filimuyo. Chidziwitso: Plasma etching ndi RIE etching, ndipo ziwirizi zitha kuwonedwa ngati lingaliro lomwelo.
4. Etch Rate ndi Core Performance Index
Chithunzi 4. Core Etch Performance Index yokhudzana ndi Etch Rate
Etch rate imatanthawuza kuya kwa filimu yomwe ikuyembekezeka kufika mphindi imodzi. Ndiye zikutanthawuza chiyani kuti mtengo wa etch umasiyana kuchokera ku gawo limodzi kupita ku gawo pa chophika chimodzi?
Izi zikutanthauza kuti kuya kwa etch kumasiyanasiyana kuchokera ku gawo kupita ku gawo pa chophika. Pachifukwa ichi, ndikofunikira kukhazikitsa pomaliza (EOP) pomwe etching iyenera kuyima poganizira kuchuluka kwa etch ndi kuya kwa etch. Ngakhale EOP itakhazikitsidwa, pali madera ena omwe kuya kwa etch kumakhala kozama (kukhazikika) kapena kutsika (kutsika) kuposa momwe adakonzera poyamba. Komabe, kuchepa pang'onopang'ono kumabweretsa kuwonongeka kochulukirapo kuposa kukomoka kwambiri panthawi yolowera. Chifukwa pakakhala pansi-etching, gawo losakhazikika limalepheretsa njira zotsatila monga kuyika ion.
Pakadali pano, kusankha (kuyezedwa ndi etch rate) ndichizindikiro chachikulu chakuchitapo kanthu. Muyezo woyezera umatengera kuyerekeza kwa etch rate ya chigoba wosanjikiza (photoresist film, oxide film, silicon nitride film, etc.) ndi chandamale chandamale. Izi zikutanthauza kuti kusankha kwapamwamba kwambiri, ndikothamanga kwambiri komwe chandamale chimakhazikika. Kukwera kwapamwamba kwa miniaturization, kumapangitsa kuti pakhale kufunikira kosankha ndikuwonetsetsa kuti mawonekedwe abwino atha kuwonetsedwa bwino. Popeza mayendedwe etching ndi molunjika, selectivity wa cationic etching ndi otsika, pamene selectivity wa etching kwambiri ndi mkulu, amene bwino selectivity wa RIE.
5. Etching ndondomeko
Chithunzi 5. Etching ndondomeko
Choyamba, chophatikizikacho chimayikidwa mu ng'anjo ya okosijeni ndi kutentha komwe kumasungidwa pakati pa 800 ndi 1000 ℃, ndiyeno filimu ya silicon dioxide (SiO2) yokhala ndi zinthu zambiri zotsekemera imapangidwa pamwamba pa mtandawo ndi njira youma. Kenaka, ndondomekoyi imalowetsedwa kuti ipange silicon layer kapena conductive layer pa filimu ya oxide ndi chemical vapor deposition (CVD)/physical vapor deposition (PVD). Ngati wosanjikiza wa silicon wapangidwa, njira yofalitsa zonyansa imatha kuchitidwa kuti muwonjezere kuwongolera ngati kuli kofunikira. Panthawi ya kufalitsa zonyansa, zonyansa zambiri zimawonjezeredwa mobwerezabwereza.
Panthawi imeneyi, wosanjikiza insulating ndi wosanjikiza polysilicon ayenera pamodzi etching. Choyamba, photoresist imagwiritsidwa ntchito. Kenako, chigoba amaikidwa pa photoresist filimu ndi chonyowa kukhudzana ikuchitika ndi kumizidwa kusindikiza ankafuna chitsanzo (wosaoneka ndi maso) pa photoresist filimu. Pamene ndondomeko yachiwonetsero imawululidwa ndi chitukuko, photoresist m'dera la photosensitive imachotsedwa. Kenako, chophwanyika chophwanyika chomwe chimakonzedwa ndi ndondomeko ya photolithography imasamutsidwa ku ndondomeko ya etching kuti ikhale yowuma.
Dry etching imachitika makamaka ndi reactive ion etching (RIE), momwe etching imabwerezedwa makamaka m'malo mwa gasi woyenera filimu iliyonse. Zowuma zowuma komanso zonyowa zimafuna kukulitsa chiŵerengero (mtengo wa A/R) wa etching. Kuphatikiza apo, kuyeretsa nthawi zonse kumafunika kuchotsa polima yomwe idasonkhanitsidwa pansi pa dzenje (mpata wopangidwa ndi etching). Mfundo yofunika ndi yakuti zosintha zonse (monga zipangizo, gasi, nthawi, mawonekedwe ndi ndondomeko) ziyenera kusinthidwa mwakuthupi kuti zitsimikizire kuti njira yoyeretsera kapena mpweya wa plasma ukhoza kutsika pansi pa ngalandeyo. Kusintha pang'ono pakusintha kumafuna kuwerengeranso zosinthika zina, ndipo kuwerengeranso kumeneku kumabwerezedwa mpaka kukwaniritse cholinga cha gawo lililonse. Posachedwapa, zigawo za monoatomic monga atomic layer deposition (ALD) zakhala zoonda komanso zolimba. Chifukwa chake, ukadaulo wa etching ukupita kukugwiritsa ntchito kutentha kochepa komanso kupanikizika. Njira yolumikizira ikufuna kuwongolera gawo lofunikira (CD) kuti lipange mawonekedwe abwino ndikuwonetsetsa kuti zovuta zomwe zimayambitsidwa ndi njira yolumikizira zimapewedwa, makamaka zocheperako komanso zovuta zokhudzana ndi kuchotsa zotsalira. Zolemba ziwiri zomwe zili pamwambazi zokhuza etching zikufuna kupereka owerenga chidziwitso cha cholinga cha etching, zopinga zomwe zili pamwambazi, komanso zisonyezo zantchito zomwe zimagwiritsidwa ntchito kuthana ndi zopinga zotere.
Nthawi yotumiza: Sep-10-2024