Kudula koyambirira konyowa kunathandizira chitukuko cha njira zoyeretsera kapena kupukuta phulusa. Masiku ano, kudula kouma pogwiritsa ntchito plasma kwakhala njira yodziwika bwino.njira yochekaPlasma imakhala ndi ma elekitironi, ma cations ndi ma radicals. Mphamvu yomwe imagwiritsidwa ntchito pa plasma imapangitsa kuti ma elekitironi akunja kwa mpweya woyambira omwe ali mu mkhalidwe wopanda kulowerera achotsedwe, motero amasintha ma elekitironi awa kukhala ma cations.
Kuphatikiza apo, maatomu osakwanira m'mamolekyu amatha kuchotsedwa pogwiritsa ntchito mphamvu kuti apange ma radicals osalowerera magetsi. Kudula kouma kumagwiritsa ntchito ma cations ndi ma radicals omwe amapanga plasma, pomwe ma cations ndi anisotropic (oyenera kudula mbali ina) ndipo ma radical ndi isotropic (oyenera kudula mbali zonse). Chiwerengero cha ma radicals ndi chachikulu kwambiri kuposa chiwerengero cha ma cations. Pankhaniyi, kudula kouma kuyenera kukhala isotropic ngati kudula konyowa.
Komabe, ndi kupukutira kwa anisotropic kwa kupukutira kouma komwe kumapangitsa kuti ma circuits opangidwa ndi ultra-miniaturized athe. Kodi chifukwa chake ndi chiyani? Kuphatikiza apo, liwiro la kupukutira kwa ma cations ndi ma radicals ndi lochepa kwambiri. Ndiye tingagwiritse ntchito bwanji njira zopukutira plasma popanga zinthu zambiri poyang'anizana ndi vuto ili?
1. Chiŵerengero cha Mawonekedwe (A/R)
Chithunzi 1. Lingaliro la chiŵerengero cha mbali ndi momwe kupita patsogolo kwaukadaulo kumakhudzira
Chiŵerengero cha Mawonekedwe ndi chiŵerengero cha m'lifupi mopingasa ndi kutalika koyima (mwachitsanzo, kutalika kogawidwa ndi m'lifupi). Kagawo kakang'ono ka critical dimension (CD) kamene kali kofunikira, chiŵerengero cha mawonekedwe chikukula. Izi zikutanthauza kuti, poganiza kuti chiŵerengero cha mawonekedwe cha 10 ndi m'lifupi cha 10nm, kutalika kwa dzenje lomwe labowoledwa panthawi yocheka kuyenera kukhala 100nm. Chifukwa chake, pazinthu za m'badwo wotsatira zomwe zimafuna ultra-miniaturization (2D) kapena high density (3D), ma aspect ratio apamwamba kwambiri amafunika kuti zitsimikizire kuti ma cations amatha kulowa mufilimu yapansi panthawi yocheka.
Kuti tikwaniritse ukadaulo wa ultra-miniaturization wokhala ndi gawo lofunikira losakwana 10nm muzinthu za 2D, mtengo wa capacitor aspect ratio wa dynamic random access memory (DRAM) uyenera kusungidwa pamwamba pa 100. Mofananamo, 3D NAND flash memory imafunanso ma aspect ratio apamwamba kuti ipange zigawo 256 kapena kuposerapo za zigawo zosungira maselo. Ngakhale zinthu zofunika pazochitika zina zitakwaniritsidwa, zinthu zofunika sizingapangidwe ngatinjira yochekasichili pamlingo woyenera. Ichi ndichifukwa chake ukadaulo wopaka utoto ukukulirakulira.
2. Chidule cha kupukutira kwa plasma
Chithunzi 2. Kudziwa gwero la mpweya wa plasma malinga ndi mtundu wa filimu
Pamene chitoliro chopanda kanthu chikugwiritsidwa ntchito, m'mimba mwake wa chitoliro chikachepa, zimakhala zosavuta kuti madzi alowe, zomwe zimatchedwa kuti capillary phenomenon. Komabe, ngati dzenje (lotsekedwa) liyenera kubooledwa pamalo owonekera, kulowa kwa madzi kumakhala kovuta kwambiri. Chifukwa chake, popeza kukula kofunikira kwa dera kunali 3um mpaka 5um pakati pa zaka za m'ma 1970, zoumakudulaPang'onopang'ono yalowa m'malo mwa wet etching ngati chinthu chachikulu. Izi zikutanthauza kuti, ngakhale kuti yasinthidwa kukhala ion, n'zosavuta kulowa m'mabowo akuya chifukwa kuchuluka kwa molekyulu imodzi ndi kochepa kuposa kwa molekyulu ya organic polymer solution.
Pakujambula plasma, mkati mwa chipinda chogwiritsira ntchito pojambula pulasitiki muyenera kusinthidwa kuti mukhale ndi mpweya woipa musanalowetse mpweya woipa wa plasma woyenera gawo loyenera. Pojambula mafilimu olimba a oxide, mpweya wamphamvu wochokera ku carbon fluoride uyenera kugwiritsidwa ntchito. Pa mafilimu ofooka a silicon kapena achitsulo, mpweya wochokera ku plasma wochokera ku chlorine uyenera kugwiritsidwa ntchito.
Ndiye, kodi gawo la chipata ndi gawo loteteza la silicon dioxide (SiO2) ziyenera kudulidwa bwanji?
Choyamba, pa gawo la chipata, silicon iyenera kuchotsedwa pogwiritsa ntchito plasma yochokera ku chlorine (silicon + chlorine) yokhala ndi polysilicon etching selectivity. Pa gawo loteteza pansi, filimu ya silicon dioxide iyenera kujambulidwa m'magawo awiri pogwiritsa ntchito mpweya wochokera ku plasma wochokera ku carbon fluoride (silicon dioxide + carbon tetrafluoride) yokhala ndi kusankha kwamphamvu komanso kogwira mtima.
3. Njira yopangira ma ion osinthika (RIE kapena physicochemical etching)
Chithunzi 3. Ubwino wa kuuma kwa ma ion osinthika (anisotropy ndi kuchuluka kwa kuuma kwakukulu)
Plasma ili ndi ma isotropic free radicals ndi ma anisotropic cations, ndiye kodi imagwira ntchito bwanji pochotsa ma anisotropic?
Kudula kouma kwa plasma kumachitika makamaka pogwiritsa ntchito njira yogwiritsira ntchito ma ion etching (RIE, Reactive Ion Etching) kapena kugwiritsa ntchito pogwiritsa ntchito njira iyi. Cholinga chachikulu cha njira ya RIE ndikuchepetsa mphamvu yomangirira pakati pa mamolekyu omwe ali mufilimuyi powukira malo odula ndi ma cations anisotropic. Malo ofookawo amatengedwa ndi ma free radicals, kuphatikiza ndi tinthu tating'onoting'ono tomwe timapanga gawolo, kusandulika kukhala mpweya (chosakaniza chosasunthika) ndikutulutsidwa.
Ngakhale kuti ma free radicals ali ndi mawonekedwe a isotropic, mamolekyu omwe amapanga pansi (omwe mphamvu yake yomangirira imafooka chifukwa cha kuukira kwa ma cations) amagwidwa mosavuta ndi ma free radicals ndikusinthidwa kukhala mankhwala atsopano kuposa makoma am'mbali okhala ndi mphamvu yamphamvu yomangirira. Chifukwa chake, kutsika pansi kumakhala chinthu chachikulu. Tinthu tomwe tagwidwa timakhala mpweya wokhala ndi ma free radicals, omwe amachotsedwa ndikutulutsidwa pamwamba pogwiritsa ntchito vacuum.
Panthawiyi, ma cations omwe amapezeka pogwiritsa ntchito mphamvu ya thupi ndi ma free radicals omwe amapezeka pogwiritsa ntchito mphamvu ya mankhwala amaphatikizidwa kuti agwiritsidwe ntchito pokonza thupi ndi mankhwala, ndipo kuchuluka kwa etching (Etch Rate, kuchuluka kwa etching munthawi inayake) kumawonjezeka ndi nthawi 10 poyerekeza ndi nkhani ya cationic etching kapena free radical etching yokha. Njirayi sikuti ingangowonjezera kuchuluka kwa etching kwa anisotropic downward etching, komanso kuthetsa vuto la ma polymer residue pambuyo pokonza. Njirayi imatchedwa reactive ion etching (RIE). Chinsinsi cha kupambana kwa RIE etching ndikupeza mpweya wochokera ku plasma woyenera etching filimuyo. Dziwani: Plasma etching ndi RIE etching, ndipo ziwirizi zitha kuonedwa ngati lingaliro lomwelo.
4. Etch Rate ndi Core Performance Index
Chithunzi 4. Core Etch Performance Index yokhudzana ndi Etch Rate
Kuchuluka kwa etch kumatanthauza kuzama kwa filimu yomwe ikuyembekezeka kufikidwa mu mphindi imodzi. Ndiye zikutanthauza chiyani kuti kuchuluka kwa etch kumasiyana kuchokera pa gawo limodzi kupita pa wafer imodzi?
Izi zikutanthauza kuti kuya kwa etch kumasiyana kuchokera ku gawo lina kupita ku lina pa wafer. Pachifukwa ichi, ndikofunikira kwambiri kukhazikitsa malo otsiriza (EOP) pomwe etch iyenera kuyima poganizira kuchuluka kwa etch ndi kuya kwa etch. Ngakhale EOP itakhazikitsidwa, pali madera ena omwe kuya kwa etch kuli kozama (kokhala ndi ma etch ambiri) kapena kocheperako (kokhala ndi ma etch ambiri) kuposa momwe adakonzera poyamba. Komabe, etch yochepa imayambitsa kuwonongeka kwakukulu kuposa etch yowonjezera panthawi yocheka. Chifukwa pankhani ya etch yochepa, gawo lokhala ndi ma etch ochepa lidzalepheretsa njira zotsatirazi monga kuyika ma ion.
Pakadali pano, kusankha (komwe kumayesedwa ndi kuchuluka kwa etch) ndi chizindikiro chofunikira cha ntchito yodula. Muyezo woyezera umachokera pakuyerekeza kwa kuchuluka kwa etch kwa chigoba (photoresist film, oxide film, silicon nitride film, ndi zina zotero) ndi gawo lolunjika. Izi zikutanthauza kuti kusankha kwakukulu, gawo lolunjika limadulidwa mwachangu. Mlingo wocheperako wa miniaturization, ndikofunikira kwambiri kuti muwonetsetse kuti mapangidwe abwino azitha kuwonetsedwa bwino. Popeza njira yodula ndi yolunjika, kusankha kwa cationic etching kumakhala kochepa, pomwe kusankha kwa radical etching kumakhala kwakukulu, zomwe zimapangitsa kuti RIE ikhale yabwino.
5. Njira yodulira
Chithunzi 5. Njira yocheka
Choyamba, wafer imayikidwa mu uvuni wa okosijeni ndi kutentha komwe kumasungidwa pakati pa 800 ndi 1000℃, kenako filimu ya silicon dioxide (SiO2) yokhala ndi mphamvu zambiri zotetezera imapangidwa pamwamba pa wafer pogwiritsa ntchito njira youma. Kenako, njira yoyikamo imalowetsedwa kuti ipange silicon layer kapena conductive layer pa oxide film ndi chemical vapor deposition (CVD)/physical vapor deposition (PVD). Ngati silicon layer yapangidwa, njira yogawa zodetsa ikhoza kuchitidwa kuti iwonjezere conductivity ngati pakufunika kutero. Panthawi yogawa zodetsa, zodetsa zambiri nthawi zambiri zimawonjezedwa mobwerezabwereza.
Panthawiyi, gawo loteteza kutentha ndi gawo la polysilicon ziyenera kugwirizanitsidwa kuti zipse. Choyamba, choletsa kuwala chimagwiritsidwa ntchito. Pambuyo pake, chigoba chimayikidwa pa filimu yotsutsa kuwala ndipo kuwala konyowa kumachitika pomiza kuti chithunzi chomwe mukufuna (chosawoneka ndi maso) pa filimu yotsutsa kuwala chikaonekera. Pamene mawonekedwe a chithunzi awonekera ndi chitukuko, choletsa kuwala chomwe chili m'dera losakhudzidwa ndi kuwala chimachotsedwa. Kenako, wafer wokonzedwa ndi njira ya photolithography amasamutsidwira ku njira yochotsera kuwala kuti akapse kuwala kouma.
Kudula kouma kumachitika makamaka ndi reactive ion etching (RIE), momwe kudula kumabwerezedwa makamaka posintha mpweya woyambira woyenera filimu iliyonse. Kudula kouma ndi kudula konyowa cholinga chake ndi kuwonjezera chiŵerengero cha mbali (A/R value) cha kudula. Kuphatikiza apo, kuyeretsa nthawi zonse kumafunika kuti polima yomwe yasonkhanitsidwa pansi pa dzenje (mpata wopangidwa ndi kudula). Mfundo yofunika ndi yakuti zinthu zonse (monga zipangizo, mpweya woyambira, nthawi, mawonekedwe ndi ndondomeko) ziyenera kusinthidwa mwachilengedwe kuti zitsimikizire kuti yankho loyeretsa kapena mpweya woyambira wa plasma ukhoza kuyenda pansi pa ngalande. Kusintha pang'ono kwa chinthu chosinthika kumafuna kuwerengeranso zinthu zina, ndipo njira yowerengeranso iyi imabwerezedwa mpaka itakwaniritsa cholinga cha gawo lililonse. Posachedwapa, zigawo za monoatomic monga atomic layer deposition (ALD) zigawo zakhala zoonda komanso zolimba. Chifukwa chake, ukadaulo wodula ukupita patsogolo pakugwiritsa ntchito kutentha kochepa ndi kupsinjika. Njira yodula ikufuna kuwongolera gawo lofunikira (CD) kuti lipange mapangidwe abwino ndikuwonetsetsa kuti mavuto omwe amabwera chifukwa cha kudula akupewedwa, makamaka kudula pang'ono ndi mavuto okhudzana ndi kuchotsa zotsalira. Nkhani ziwiri zomwe zili pamwambapa zokhudza kudula cholinga chake ndi kupatsa owerenga kumvetsetsa cholinga cha kudula, zopinga zomwe zingalepheretse kukwaniritsa zolinga zomwe zili pamwambapa, ndi zizindikiro za magwiridwe antchito zomwe zimagwiritsidwa ntchito kuthana ndi zopinga zotere.
Nthawi yotumizira: Sep-10-2024