Ukugrumba kwasekuqaleni ngamanzi kwakhuthaza uphuhliso lweenkqubo zokucoca okanye zokulahla uthuthu. Namhlanje, ukugrumba okomileyo kusetyenziswa iplasma kuye kwaba yinto eqhelekileyoinkqubo yokukrolaI-Plasma inee-electron, ii-cations kunye nee-radicals. Amandla asetyenziswa kwi-plasma abangela ukuba ii-electron ezingaphandle zegesi yomthombo zisuswe kwimeko engathathi cala, ngaloo ndlela ziguqula ezi electron zibe zii-cations.
Ukongeza, iiathom ezingaphelelanga kwiimolekyuli zinokususwa ngokusebenzisa amandla ukwenza iiradicals ezingathathi cala ngombane. I-Dry etching isebenzisa ii-cations kunye neeradicals ezenza i-plasma, apho ii-cations ziyi-anisotropic (zifanelekile ukukrola kwicala elithile) kwaye ii-radicals ziyi-isotropic (zifanelekile ukukrola kuzo zonke iindlela). Inani lee-radicals likhulu kakhulu kunenani lee-cations. Kule meko, i-dry etching kufuneka ibe yi-isotropic efana ne-wet etching.
Nangona kunjalo, kukugcaba kwe-anisotropic kokugcaba okomileyo okwenza ukuba iisekethe ezi-ultra-miniaturized zibe nokwenzeka. Yintoni isizathu soku? Ukongeza, isantya sokugcaba se-cations kunye ne-radicals sicotha kakhulu. Ngoko ke singazisebenzisa njani iindlela zokugcaba ze-plasma kwimveliso enkulu xa sijongene nale ngxaki?
1. Umlinganiselo woBume (A/R)
Umfanekiso 1. Ingcamango yomlinganiselo womda kunye nempembelelo yenkqubela phambili yetekhnoloji kuyo
Umlinganiselo woBume ngumlinganiselo wobubanzi obuthe tye ukuya kubude obuthe nkqo (oko kukuthi, ukuphakama okwahlulwe ngobubanzi). Okukhona ubukhulu obubalulekileyo (CD) besekethe buncinci, kokukhona ixabiso lomlinganiselo woBume likhulu. Oko kukuthi, xa sicinga ukuba ixabiso lomlinganiselo woBume liyi-10 kunye nobubanzi be-10nm, ukuphakama komngxuma ogqojoziweyo ngexesha lenkqubo yokugrumba kufuneka kube yi-100nm. Ke ngoko, kwiimveliso zesizukulwana esilandelayo ezifuna i-ultra-miniaturization (2D) okanye i-high density (3D), kufuneka ixabiso lomlinganiselo woBume obuphezulu kakhulu ukuqinisekisa ukuba ii-cations zinokungena kwifilimu esezantsi ngexesha lokugrumba.
Ukuze kufezekiswe iteknoloji ye-ultra-miniaturization enomlinganiselo obalulekileyo ongaphantsi kwe-10nm kwiimveliso ze-2D, ixabiso le-capacitor aspect ratio ye-dynamic random access memory (DRAM) kufuneka ligcinwe lingaphezulu kwe-100. Ngokufanayo, i-3D NAND flash memory ikwafuna amaxabiso aphezulu e-aspect ratio ukuze kuhlanganiswe iileya ezingama-256 okanye ngaphezulu zeeleya ze-cell stacking. Nokuba iimeko ezifunekayo kwezinye iinkqubo ziyafezekiswa, iimveliso ezifunekayo azinakuveliswa ukubainkqubo yokukrolaayifikeleleki kwimigangatho. Yiyo loo nto iteknoloji yokukrola isiya ibaluleke ngakumbi.
2. Isishwankathelo sokugrumba ngeplasma
Umfanekiso 2. Ukuchonga igesi yomthombo weplasma ngokohlobo lwefilimu
Xa kusetyenziswa umbhobho ongenanto, okukhona ububanzi bombhobho buncipha, kokukhona kulula ukuba ulwelo lungene, nto leyo ebizwa ngokuba yi-capillary phenomenon. Nangona kunjalo, ukuba kuza kugqojozwa umngxuma (isiphelo esivaliweyo) kwindawo evezwe kuyo, ukungena kolwelo kuba nzima kakhulu. Ke ngoko, ekubeni ubungakanani obubalulekileyo besekethe babuyi-3um ukuya kwi-5um phakathi kweminyaka yoo-1970, ukomisaukukrolaiye yathatha indawo yokugrumba okumanzi kancinci kancinci njengesixhobo esiqhelekileyo. Oko kukuthi, nangona yenziwe i-ionized, kulula ukungena kwimingxunya enzulu kuba umthamo wemolekyuli enye umncinci kunowemolekyuli yesisombululo sepolymer yendalo.
Ngexesha lokugrumba ngeplasma, ingaphakathi legumbi lokucubungula elisetyenziselwa ukugrumba kufuneka lilungiswe libe yimeko ye-vacuum ngaphambi kokuba kufakwe igesi yomthombo weplasma efanelekileyo kumaleko ofanelekileyo. Xa kugrumba iifilimu ze-solid oxide, kufuneka kusetyenziswe iigesi zomthombo ezinamandla ezisekelwe kwi-carbon fluoride. Kwiifilimu ze-silicon okanye zesinyithi ezibuthathaka, kufuneka kusetyenziswe iigesi zomthombo weplasma ezisekelwe kwi-chlorine.
Ngoko ke, kufuneka njani ukuba umaleko wesango kunye nomaleko wokugquma we-silicon dioxide (SiO2) ongaphantsi ukrolwe?
Okokuqala, kumaleko wesango, i-silicon kufuneka isuswe kusetyenziswa i-plasma esekelwe kwi-chlorine (i-silicon + i-chlorine) enokukhetha ukugquma kwe-polysilicon. Kumaleko ogqumayo osezantsi, ifilimu ye-silicon dioxide kufuneka igqunywe ngamanyathelo amabini kusetyenziswa igesi yomthombo we-plasma esekelwe kwi-carbon fluoride (i-silicon dioxide + i-carbon tetrafluoride) enokukhetha ukugquma okunamandla nokusebenza kakuhle.
3. Inkqubo yokutshiza ii-ion ezisebenzayo (i-RIE okanye i-physicochemical etching)
Umfanekiso 3. Iingenelo zokutshiza ii-ion ezisebenzayo (i-anisotropy kunye nesantya esiphezulu sokutshiza)
I-Plasma iqulethe zombini ii-isotropic free radicals kunye nee-anisotropic cations, ngoko ke yenza njani i-anisotropic etching?
Ukugrumba okomileyo kwiplasma kwenziwa kakhulu ngokugrumba ii-ion ezisabelayo (RIE, Reactive Ion Etching) okanye usetyenziso olusekelwe kule ndlela. Eyona nto iphambili kwindlela yeRIE kukwenza buthathaka amandla okubopha phakathi kweemolekyuli ezijoliswe kuzo kwifilimu ngokuhlasela indawo yokugrumba ngee-cations ze-anisotropic. Indawo ebuthathaka ifunxwa zii-free radicals, zidityaniswe nee-particles ezenza umaleko, ziguqulwe zibe yigesi (i-compound eguquguqukayo) kwaye zikhutshwe.
Nangona ii-free radicals zineempawu ze-isotropic, iimolekyuli ezenza umphezulu ongaphantsi (omandla azo okubopha abuthathaka kukuhlaselwa kwee-cations) zibanjwa lula zii-free radicals kwaye ziguqulwe zibe ziikhompawundi ezintsha kuneendonga ezisecaleni ezinamandla okubopha. Ke ngoko, ukugrumba okuphantsi kuba yinto ephambili. Amasuntswana abanjiweyo aba yigesi ene-free radicals, ezikhutshwayo kwaye zikhutshwe kumphezulu phantsi kwesenzo se-vacuum.
Ngeli xesha, ii-cations ezifunyenwe ngesenzo somzimba kunye nee-free radicals ezifunyenwe ngesenzo seekhemikhali zidityaniswe ukuze kufakwe i-physical kunye nee-chemical etching, kwaye izinga lokugrumba (i-Etch Rate, inqanaba lokugrumba kwixesha elithile) linyuswa ngamaxesha ali-10 xa kuthelekiswa nemeko yokugrumba kwe-cationic okanye ukugrumba kwe-free radical kuphela. Le ndlela ayinakunyusa kuphela izinga lokugrumba kwe-anisotropic downward etching, kodwa ikwasombulula ingxaki ye-polymer residue emva kokugrumba. Le ndlela ibizwa ngokuba yi-reactive ion etching (RIE). Isitshixo sempumelelo yokugrumba kwe-RIE kukufumana igesi yomthombo we-plasma efanelekileyo yokugrumba ifilimu. Qaphela: Ukugrumba kwe-plasma kukugrumba kwe-RIE, kwaye ezi zimbini zinokuthathwa njengengcamango efanayo.
4. Ireyithi yokuQokelela kunye neSalathiso sokuSebenza okuPhambili
Umfanekiso 4. Isalathisi sokuSebenza kwe-Core Etch esinxulumene ne-Etch Rate
Izinga lokugcagca libhekisa kubunzulu befilimu ekulindeleke ukuba ifikelelwe ngomzuzu omnye. Ngoko ke kuthetha ukuthini ukuba izinga lokugcagca lahluka ukusuka kwinxalenye ukuya kwenye kwi-wafer enye?
Oku kuthetha ukuba ubunzulu be-etch buyahluka ukusuka kwinxalenye ukuya kwenye kwi-wafer. Ngenxa yesi sizathu, kubaluleke kakhulu ukumisela isiphelo (i-EOP) apho ukugrumba kufanele kume khona ngokuqwalasela isantya esiphakathi se-etch kunye nobunzulu be-etch. Nokuba i-EOP isetiwe, kusekho iindawo apho ubunzulu be-etch bunzulu (bugqithisile) okanye bungaphantsi (bungaphantsi kwe-etch) kunokuba bekucwangcisiwe ekuqaleni. Nangona kunjalo, ukugrumba okungaphantsi kwe-etch kubangela umonakalo omkhulu kunokugrumba okungaphezulu ngexesha lokugrumba. Kuba kwimeko yokugrumba okungaphantsi kwe-etch, inxalenye engaphantsi kwe-etch iya kuthintela iinkqubo ezilandelayo ezifana nokufakelwa kwe-ion.
Okwangoku, ukukhetha (okulinganiswe ngesantya se-etch) sisalathisi esiphambili sokusebenza kwenkqubo yokugrumba. Umgangatho wokulinganisa usekwe ekuthelekisweni kwesantya se-etch yomaleko wemaski (ifilimu ye-photoresist, ifilimu ye-oxide, ifilimu ye-silicon nitride, njl.njl.) kunye nomaleko ekujoliswe kuwo. Oku kuthetha ukuba xa ukhetha okuphezulu, kokukhona umaleko ekujoliswe kuwo ugrumba ngokukhawuleza. Okukhona inqanaba le-miniaturization liphezulu, kokukhona imfuneko yokukhetha iphezulu ukuqinisekisa ukuba iipateni ezincinci zinokuboniswa ngokugqibeleleyo. Ekubeni ulwalathiso lokugrumba luthe tye, ukukhetha kwe-cationic etching kuphantsi, ngelixa ukukhetha kwe-radical etching kuphezulu, okuphucula ukukhetha kwe-RIE.
5. Inkqubo yokukrola
Umfanekiso 5. Inkqubo yokukrola
Okokuqala, i-wafer ifakwa kwisithando somlilo esinobushushu obuphakathi kwama-800 nama-1000℃, emva koko ifilimu ye-silicon dioxide (SiO2) eneempawu eziphezulu zokuthintela ubushushu yenziwe phezu komphezulu we-wafer ngendlela eyomileyo. Okulandelayo, inkqubo yokufaka ifakwa ukuze kwenziwe umaleko we-silicon okanye umaleko oqhubayo kwifilimu ye-oxide yi-chemical vapor deposition (CVD)/physical vapor deposition (PVD). Ukuba umaleko we-silicon wenziwe, inkqubo yokusasazwa kokungcola inokwenziwa ukuze kwandiswe ukuhanjiswa komoya ukuba kuyimfuneko. Ngexesha lenkqubo yokusasazwa kokungcola, ukungcola okuninzi kudla ngokufakwa ngokuphindaphindiweyo.
Ngeli xesha, umaleko wokuthintela ubushushu kunye nomaleko we-polysilicon kufuneka zidityaniswe ukuze kugrunjwe. Okokuqala, kusetyenziswa i-photoresist. Emva koko, kufakwa imaski kwifilimu ye-photoresist kwaye ukuvezwa okumanzi kwenziwa ngokuntywiliselwa ukuze kuprintwe ipateni efunekayo (engabonakaliyo emehlweni) kwifilimu ye-photoresist. Xa umphezulu wepateni utyhilwa luphuhliso, i-photoresist kwindawo ebuthathaka kukukhanya iyasuswa. Emva koko, i-wafer ecutshungulwa yinkqubo ye-photolithography idluliselwa kwinkqubo yokugrunjwa ukuze kugrunjwe okomileyo.
Ukugrumba okomileyo kwenziwa kakhulu ngokugrumba i-ion ephendulayo (RIE), apho ukugrumba kuphindaphindwa ikakhulu ngokutshintsha igesi yomthombo efanelekileyo kwifilimu nganye. Ukugrumba okomileyo kunye nokugrumba okumanzi kujolise ekwandiseni umlinganiselo womphezulu (ixabiso le-A/R) lokugrumba. Ukongeza, ukucoca rhoqo kuyadingeka ukususa i-polymer eqokelelwe ezantsi komngxuma (umsantsa owenziwe kukugrumba). Ingongoma ebalulekileyo kukuba zonke izinto eziguquguqukayo (ezifana nezixhobo, igesi yomthombo, ixesha, imo kunye nolandelelwano) kufuneka zilungiswe ngokwendalo ukuqinisekisa ukuba isisombululo sokucoca okanye igesi yomthombo weplasma inokuhla iye ezantsi komsele. Utshintsho oluncinci kwinguquko lufuna ukubalwa kwakhona kwezinye izinto eziguquguqukayo, kwaye le nkqubo yokubala kwakhona iphindaphindwa ide ifezekise injongo yesigaba ngasinye. Kutshanje, iileya ze-monoatomic ezifana neeleya ze-atomic layer deposition (ALD) ziye zaba ncinci kwaye zaba nzima. Ke ngoko, itekhnoloji yokugrumba isiya ekusebenziseni amaqondo obushushu aphantsi kunye noxinzelelo. Inkqubo yokugrumba ijolise ekulawuleni ubukhulu obubalulekileyo (CD) ukuvelisa iipateni ezintle kunye nokuqinisekisa ukuba iingxaki ezibangelwa yinkqubo yokugrumba ziyaphetshwa, ingakumbi ukugrumba okungaphelelanga kunye neengxaki ezinxulumene nokususwa kweentsalela. Amanqaku amabini angentla malunga nokugrumba ajolise ekunikeni abafundi ukuqonda injongo yenkqubo yokugrumba, imiqobo ekufezekiseni iinjongo ezingentla, kunye neempawu zokusebenza ezisetyenziswa ukoyisa loo miqobo.
Ixesha leposi: Septemba-10-2024