Ukuthungwa okumanzi kwangaphambili kwakhuthaza ukuphuhliswa kweenkqubo zokucoca okanye uthuthu. Namhlanje, i-etching eyomileyo esebenzisa iplasma iye yaba yeyona nto iphambiliinkqubo etching. I-Plasma iqulethe ii-electron, ii-cations kunye neeradicals. Amandla asetyenziswa kwi-plasma abangela ukuba ii-electron zangaphandle zomthombo wegesi kwindawo engathathi hlangothi zihluthwe, ngaloo ndlela ziguqula ezi electron zibe cations.
Ukongeza, iiathomu ezingafezekanga kwiimolekyuli zinokuhluthwa ngokusebenzisa amandla ukwenza iiradicals zombane ezingathathi hlangothi. I-etching eyomileyo isebenzisa i-cations kunye ne-radicals eyenza i-plasma, apho i-cations i-anisotropic (ifanele ukubethelwa kwicala elithile) kunye ne-radicals i-isotropic (ifanele ukubethelwa macala onke). Inani leeradicals likhulu kakhulu kunenani leecations. Kule meko, i-etching eyomileyo kufuneka ibe yi-isotropic njenge-etching emanzi.
Nangona kunjalo, yi-anisotropic etching ye-etching eyomileyo eyenza ukuba iisekethe ze-ultra-miniaturized zenzeke. Siyintoni isizathu soku? Ukongeza, isantya se-cations kunye neeradicals sicotha kakhulu. Ke singazisebenzisa njani iindlela zokutsala iplasma kwimveliso yobuninzi phambi kolu kusilela?
1. Ubungakanani bobume (A/R)
Umzobo 1. Ingqikelelo yomlinganiso wenkalo kunye nefuthe lenkqubela phambili yezobuchwepheshe kuyo
I-Aspect Ratio ngumlinganiselo wobubanzi obuthe tye ukuya kubude obuthe nkqo (okt, ubude obahlulwe ngobubanzi). Umncinci umlinganiselo obalulekileyo (CD) wesekethe, inkulu i-aspect ratio yexabiso. Oko kukuthi, ukulinganisa ixabiso le-aspect ratio ye-10 kunye nobubanzi be-10nm, ukuphakama komngxuma owenziwe ngexesha lenkqubo yokubhala kufuneka ibe yi-100nm. Ke ngoko, kwiimveliso zesizukulwana esilandelayo ezifuna i-ultra-miniaturization (2D) okanye i-high density (3D), amaxabiso aphezulu kakhulu afunekayo ukuze kuqinisekiswe ukuba ii-cations zinokungena kwifilimu engezantsi ngexesha lokufakwa.
Ukufezekisa itekhnoloji ye-ultra-miniaturization enomlinganiselo obalulekileyo ongaphantsi kwe-10nm kwiimveliso ze-2D, i-capacitor aspect ratio yexabiso le-dynamic access memory (DRAM) kufuneka igcinwe ngaphezulu kwe-100. ukupakisha iileya ezingama-256 okanye ngaphezulu zomaleko wokupakisha iiseli. Nokuba iimeko ezifunekayo kwezinye iinkqubo zihlangatyezwana, iimveliso ezifunekayo azinakuveliswa ukubainkqubo etchingayikho kumgangatho. Kungenxa yoko le nto itekhnoloji ye-etching isiya ibaluleke kakhulu.
2. Isishwankathelo se-plasma etching
Umzobo 2. Ukugqiba umthombo wegesi yeplasma ngokohlobo lwefilimu
Xa kusetyenziswe umbhobho ongenanto, i-diameter yepayipi iyancipha, kulula ukuba i-liquid ingene, into ebizwa ngokuba yi-capillary phenomenon. Nangona kunjalo, ukuba umngxuma (isiphelo esivaliweyo) siza kugrunjwa kwindawo evulekileyo, igalelo lolwelo liba nzima kakhulu. Ke ngoko, kuba ubukhulu besekethe yayiyi-3um ukuya kwi-5um phakathi koo-1970, yoma.etchingngokuthe ngcembe ithathe indawo ye-etching emanzi njengeyona nto iphambili. Oko kukuthi, nangona i-ionized, kulula ukungena kwimingxuma enzulu ngenxa yokuba umthamo we-molecule enye incinci kune-organic polymer solution molecule.
Ngexesha le-plasma etching, ingaphakathi legumbi lokucubungula elisetyenziselwa ukubethelwa kufuneka lihlengahlengiswe kwindawo yokucoca ngaphambi kokutofa igesi yomthombo we-plasma elungele umaleko ofanelekileyo. Xa ufaka iifilimu eziqinileyo zeoksidi, kufuneka kusetyenziswe igesi ezomeleleyo ezisekwe kwikhabhoni fluoride. Kwi-silicon ebuthathaka okanye iifilimu zetsimbi, igesi yomthombo weplasma esekwe kwiklorin kufuneka isetyenziswe.
Ke, umaleko wesango kunye ne-silicon dioxide engaphantsi (i-SiO2) ye-insulating layer kufanele ifakwe njani?
Okokuqala, kuluhlu lwesango, i-silicon kufuneka isuswe ngokusebenzisa i-plasma esekelwe kwi-chlorine (i-silicon + chlorine) kunye ne-polysilicon etching selectivity. Kumaleko wokugquma osezantsi, ifilimu yesilicon dioxide kufuneka imiswe ngamanyathelo amabini kusetyenziswa igesi yomthombo weplasma esekelwe kwikhabhoni fluoride (isilicon dioxide + carbon tetrafluoride) ngokukhetha okunamandla kunye nokusebenza kakuhle.
3. I-ion etching esebenzayo (i-RIE okanye i-physicochemical etching) inkqubo
Umzobo 3. I-advanteji ye-ion etching esebenzayo (i-anisotropy kunye nesantya esiphezulu sokulinganisa)
IPlasma iqulethe zombini iiradicals zasimahla ze-isotropic kunye ne-anisotropic cations, ke iyenza njani i-anisotropic etching?
I-Plasma dry etching yenziwa ikakhulu yi-reactive ion etching (RIE, Reactive Ion Etching) okanye izicelo ezisekelwe kule ndlela. Undoqo wendlela ye-RIE kukwenza buthathaka amandla okubopha phakathi kweemolekyuli ekujoliswe kuzo kwifilimu ngokuhlasela indawo yokuqhafaza nge-anisotropic cations. Ummandla obuthathaka uxutywa ngama-radicals amahhala, adibaniswe kunye neengqungquthela ezenza i-layer, iguqulelwe kwi-gas (i-compound eguqukayo) kwaye ikhululwe.
Nangona i-radicals yamahhala ineempawu ze-isotropic, iamolekyu ezenza umgangatho ophantsi (amandla abo okubopha ayancipha ngenxa yokuhlaselwa kwee-cations) athatyathwa ngokulula ngama-radicals amahhala kwaye aguqulelwe kwiingqungquthela ezintsha kuneendonga zecala ezinamandla okubopha ngamandla. Ke ngoko, i-etching ezantsi iba yeyona nto iphambili. Iingqungquthela ezibanjiweyo ziba yigesi kunye ne-radicals yamahhala, echithwayo kwaye ikhutshwe ebusweni phantsi kwesenzo se-vacuum.
Ngeli xesha, i-cations efunyenwe ngesenzo somzimba kunye ne-radicals yamahhala efunyenwe ngesenzo sekhemikhali idityaniswe kwi-etching ngokomzimba kunye neekhemikhali, kunye nesantya sokulinganisa (i-Etch Rate, i-degree of etching kwixesha elithile) yanda ngamaxesha angama-10. xa kuthelekiswa nemeko ye-cationic etching okanye i-radical etching yasimahla yodwa. Le ndlela ayinako nje ukunyusa izinga lokurhweba kwe-anisotropic ezantsi, kodwa iphinde isombulule ingxaki yentsalela ye-polymer emva kokufakwa. Le ndlela ibizwa ngokuba yi-reactive ion etching (RIE). Isitshixo kwimpumelelo ye-RIE etching kukufumana igesi yomthombo weplasma elungele ukujongwa kwefilimu. Qaphela: I-Plasma etching yi-RIE etching, kwaye ezi zimbini zinokuthathwa njengengcamango efanayo.
4. I-Etch Rate kunye ne-Core Performance Index
Umzobo 4. I-Core Etch Performance Index enxulumene ne-Etch Rate
I-Etch rate ibhekisa kubunzulu befilimu ekulindeleke ukuba ifikelelwe ngomzuzu omnye. Ke kuthetha ukuthini ukuba ireyithi ye-etch iyahluka ukusuka kwinxalenye ukuya kwinxalenye kwi-wafer enye?
Oku kuthetha ukuba ubunzulu be-etch buyahluka ukusuka kwinxalenye ukuya kwinxalenye kwi-wafer. Ngesi sizathu, kubaluleke kakhulu ukuseta indawo yokuphela (EOP) apho ukufakwa kufuneka kuyeke ngokuqwalasela umyinge we-etch rate kunye nobunzulu be-etch. Nokuba i-EOP isetiwe, kusekho iindawo ezithile apho ubunzulu be-etch bunzulu (i-etch-etched) okanye bunzulu (i-under-etched) kunokuba bekucwangcisiwe ekuqaleni. Nangona kunjalo, i-under-etching ibangela umonakalo omkhulu kunokugqithisa kakhulu ngexesha le-etching. Ngenxa yokuba kwimeko ye-etching engaphantsi, inxalenye engaphantsi kwe-etched iya kuthintela iinkqubo ezilandelayo ezifana nokufakelwa kwe-ion.
Okwangoku, ukukhetha (kulinganiswa ngomlinganiselo we-etch) luphawu oluphambili lomsebenzi wenkqubo yokubhala. Umgangatho wokulinganisa usekelwe ekuthelekisweni kwereyithi ye-etch ye-mask layer (ifilimu ye-photoresist, ifilimu ye-oxide, ifilimu ye-silicon nitride, njl. njl.) kunye noluhlu olujoliswe kuyo. Oku kuthetha ukuba ukukhethwa okuphezulu, ngokukhawuleza umaleko ojoliswe kuwo ubhalwa. Inqanaba eliphezulu le-miniaturization, iphezulu imfuno yokukhetha kukuqinisekisa ukuba iipatheni ezintle zinokubonakaliswa ngokugqibeleleyo. Ekubeni ulwalathiso lwe-etching luthe tye, ukhetho lwe-cationic etching luphantsi, ngelixa ukhetho lwe-radical etching luphezulu, oluphucula ukhetho lwe-RIE.
5. Inkqubo etching
Umzobo 5. Inkqubo ye-etching
Okokuqala, i-wafer ifakwe kwi-oxidation oxidation kunye neqondo lokushisa eligcinwe phakathi kwe-800 kunye ne-1000 ℃, kwaye emva koko ifilimu ye-silicon dioxide (SiO2) eneempawu eziphezulu zokugquma yenziwa phezu komphezulu we-wafer ngendlela eyomileyo. Okulandelayo, inkqubo yokubeka ingeniswa ukwenza umaleko wesilicon okanye umaleko oqhubayo kwifilimu ye-oxide ngekhemikhali yomphunga deposition (CVD)/physical vapor deposition (PVD). Ukuba umaleko we-silicon wenziwe, inkqubo yokusabalalisa ukungcola inokwenziwa ukuze kwandiswe i-conductivity ukuba kuyimfuneko. Ngethuba lenkqubo yokusasazwa kokungcola, ukungcola okuphindaphindiweyo kongezwa ngokuphindaphindiweyo.
Ngeli xesha, i-insulating layer kunye ne-polysilicon layer kufuneka idityaniswe ukuze ifakwe. Okokuqala, i-photoresist isetyenziswa. Emva koko, imaski ibekwe kwifilimu ye-photoresist kunye nokuvezwa okumanzi kwenziwa ngokuntywiliselwa ukuprinta ipateni efunwayo (engabonakaliyo ngeso lenyama) kwifilimu ye-photoresist. Xa ulwandlalo lwepateni lutyhilwa ngophuhliso, i-photoresist kwindawo ye-photosensitive iyasuswa. Emva koko, i-wafer ecutshungulwayo yinkqubo ye-photolithography idluliselwa kwinkqubo yokufaka i-etching eyomileyo.
I-Dry etching iqhutywa ikakhulu yi-reactive ion etching (RIE), apho ugcino luphindwa ngokuphindaphindiweyo ngokutshintsha igesi yomthombo efanelekileyo kwifilimu nganye. Zombini i-etching eyomileyo kunye ne-etching emanzi ijolise ekunyuseni umlinganiselo we-aspect ratio (ixabiso le-A / R) le-etching. Ukongezelela, ukucocwa rhoqo kuyadingeka ukususa i-polymer eqokelelwe phantsi komngxuma (i-gap eyenziwe yi-etching). Ingongoma ebalulekileyo kukuba zonke izinto eziguquguqukayo (ezifana nezixhobo, igesi yomthombo, ixesha, ifom kunye nokulandelelana) kufuneka zilungelelaniswe ngokwezinto eziphilayo ukuze kuqinisekiswe ukuba isisombululo sokucoca okanye igesi ye-plasma inokuhamba ukuya phantsi komsele. Utshintsho oluncinci kwi-variable lufuna ukubalwa kwakhona kwezinye izinto eziguquguqukayo, kwaye le nkqubo yokubala iphinda iphindwe ide ihlangabezane nenjongo yesigaba ngasinye. Kutshanje, iileya ze-monoatomic ezifana ne-atomic layer deposition (ALD) ziye zaqina kwaye zaqina. Ke ngoko, itekhnoloji ye-etching ihambela ekusetyenzisweni kwamaqondo obushushu aphantsi kunye noxinzelelo. Inkqubo ye-etching ijolise ekulawuleni umlinganiselo obaluleke kakhulu (CD) ukuvelisa iipatheni ezintle kunye nokuqinisekisa ukuba iingxaki ezibangelwa yinkqubo ye-etching ziyagwenywa, ngakumbi ukucima kunye neengxaki ezinxulumene nokususwa kwentsalela. La manqaku mabini angasentla malunga ne-etching ajolise ekunikeni abafundi ukuqonda ngenjongo yenkqubo yokubhala, imiqobo ekuphumezeni ezi njongo zingasentla, kunye nezalathisi zokusebenza ezisetyenziselwa ukoyisa loo miqobo.
Ixesha lokuposa: Sep-10-2024