Isingeniso esisodwa
I-Etching kunqubo yokukhiqiza isekethe ehlanganisiwe ihlukaniswe yaba:
- Ukukhipha amanzi;
-Ukoma okomile.
Ezinsukwini zakuqala, i-etching emanzi yayisetshenziswa kakhulu, kodwa ngenxa yokulinganiselwa kwayo ekulawuleni ububanzi bomugqa kanye ne-etching directionality, izinqubo eziningi ngemva kwe-3μm zisebenzisa i-etching eyomile. Ukufakwa okumanzi kusetshenziswa kuphela ukususa izendlalelo ezithile zezinto ezikhethekile nezinsalela ezihlanzekile.
I-etching eyomile isho inqubo yokusebenzisa izinsimbi zamakhemikhali anegesi ukuze kusabelene nezinto eziku-wafer ukuze kucishwe ingxenye yento ezokhishwa futhi yakhe imikhiqizo yokusabela eguquguqukayo, esuke ikhishwe egumbini lokusabela. I-Etchant ivamise ukukhiqizwa ngokuqondile noma ngokungaqondile ku-plasma yegesi ebambayo, ngakho-ke ukufakwa okomile kubizwa nangokuthi i-plasma etching.
1.1 I-Plasma
I-Plasma iyigesi esesimweni se-ionized ebuthakathaka esakhiwe ukuchichima okukhanyayo kwegesi ebambayo ngaphansi kwesenzo senkambu yangaphandle kazibuthe kagesi (njengokukhiqizwe ukunikezwa kwamandla okuvama komsakazo). Kuhlanganisa ama-electron, ama-ion kanye nezinhlayiya ezisebenzayo ezingathathi hlangothi. Phakathi kwazo, izinhlayiya ezisebenzayo zingasabela ngokuqondile ngamakhemikhali ngento eqoshiwe ukuze kuzuzwe ukucwiliswa, kodwa lokhu kusabela kwamakhemikhali okuhlanzekile ngokuvamile kwenzeka kuphela enanini elincane kakhulu lezinto futhi akuqondi; lapho ama-ion enamandla athile, angagxilwa ngokufafaza ngokomzimba okuqondile, kodwa izinga lokuhlaba lalokhu kusabela komzimba okumsulwa liphansi kakhulu futhi ukukhetha kubi kakhulu.
Ukufakwa okuningi kwe-plasma kuqedwa ngokubamba iqhaza kwezinhlayiya ezisebenzayo nama-ion ngesikhathi esifanayo. Kule nqubo, i-ion bombardment inemisebenzi emibili. Enye iwukubhubhisa izibopho ze-athomu ebusweni bento eqoshiwe, ngaleyo ndlela kwandise izinga lapho izinhlayiya ezingathathi hlangothi zisabela ngayo; enye iwukukhipha imikhiqizo yokusabela efakwe kusixhumi esibonakalayo ukuze kube lula ukuthi i-etchant ixhumane ngokugcwele nobuso bento eqoshiwe, ukuze ukushumeka kuqhubeke.
Imikhiqizo yokusabela efakwe ezindongeni eziseceleni zesakhiwo esimisiwe ayikwazi ukususwa ngempumelelo ngamabhomu e-ion aqondisayo, ngaleyo ndlela ivimbele ukuhujwa kwezindonga eziseceleni futhi yenze i-anisotropic etching.
Inqubo ye-etching yesibili
2.1 Ukucwiliswa Okumanzi Nokuhlanza
I-Wet etching ingobunye bobuchwepheshe bakuqala obusetshenziswa ekukhiqizeni isekethe edidiyelwe. Nakuba izinqubo eziningi zokuthunga ezimanzi sezithathelwe indawo yi-anisotropic dry etching ngenxa ye-isotropic etching, isadlala indima ebalulekile ekuhlanzeni izingqimba ezingabalulekile zosayizi abakhulu. Ikakhulukazi ekucushweni kwezinsalela zokususwa kwe-oxide kanye nokuhlubuka kwe-epidermal, kusebenza kahle futhi ukonga kunokuchotshozwa okomile.
Izinto ze-etching ezimanzi ikakhulukazi zifaka i-silicon oxide, i-silicon nitride, i-crystal silicon eyodwa ne-polycrystalline silicon. Ukufakwa okumanzi kwe-silicon oxide kuvame ukusebenzisa i-hydrofluoric acid (HF) njengomthwali wamakhemikhali oyinhloko. Ukuze kuthuthukiswe ukukhetha, i-dilute hydrofluoric acid evinjwe i-ammonium fluoride isetshenziswa kule nqubo. Ukuze kugcinwe ukuzinza kwenani le-pH, inani elincane le-asidi eqinile noma ezinye izakhi zingangezwa. I-silicon oxide edotshiwe igqwala kalula kune-silicon oxide emsulwa. Ukukhumula amakhemikhali amanzi kusetshenziswa ikakhulukazi ukususa i-photoresist kanye nemaski eqinile (i-silicon nitride). I-Hot phosphoric acid (H3PO4) iwuketshezi lwamakhemikhali oluyinhloko olusetshenziselwa ukuhlubula amakhemikhali amanzi ukuze kususwe i-silicon nitride, futhi inokukhethwa okuhle kwe-silicon oxide.
Ukuhlanza okumanzi kufana nokucwiliswa okumanzi, futhi kususa ikakhulukazi ukungcola okungaphezulu kwamawafa e-silicon ngokusabela kwamakhemikhali, okuhlanganisa izinhlayiya, izinto eziphilayo, izinsimbi nama-oxides. Ukuhlanza okumanzi okujwayelekile kuyindlela yamakhemikhali emanzi. Nakuba ukuhlanza okomile kungase kuthathe indawo yezindlela eziningi zokuhlanza ezimanzi, ayikho indlela engashintsha ngokuphelele ukuhlanza okumanzi.
Amakhemikhali asetshenziswa kakhulu ekuhlanzeni okumanzi ahlanganisa i-sulfuric acid, i-hydrochloric acid, i-hydrofluoric acid, i-phosphoric acid, i-hydrogen peroxide, i-ammonium hydroxide, i-ammonium fluoride, njll. Ekusetshenzisweni okungokoqobo, ikhemikhali eyodwa noma amaningi axutshwa namanzi akhishwe nge-deionized ngenani elithile njengoba kudingeka yakha isixazululo sokuhlanza, esifana ne-SC1, SC2, DHF, BHF, njll.
Ukuhlanza kuvame ukusetshenziswa kule nqubo ngaphambi kokufakwa kwefilimu ye-oxide, ngoba ukulungiswa kwefilimu ye-oxide kufanele kwenziwe endaweni ehlanzekile ye-silicon wafer. Inqubo evamile yokuhlanza i-silicon wafer imi kanje:
2.2 I-Dry Etching and Ukuhlanza
2.2.1 I-Dry Etching
Ukufakwa okomile embonini kubhekiselwa ekufakweni kwe-plasma, esebenzisa i-plasma enomsebenzi othuthukisiwe ukuze kufakwe izinto ezithile. Uhlelo lwemishini ezinqubweni zokukhiqiza ezinkulu lusebenzisa i-plasma enezinga eliphansi lokushisa elingalingani.
Ukufakwa kwe-Plasma ikakhulukazi kusebenzisa izindlela ezimbili zokukhipha: ukukhishwa okuhlanganisiwe kwe-capacitive kanye nokukhishwa okuhlanganisiwe okuhambisanayo
Kumodi yokukhipha okuhlanganisiwe okuhlanganisiwe: i-plasma ikhiqizwa futhi igcinwe kuma-plate capacitor amabili ahambisanayo yi-external radio frequency (RF) power supply. Ingcindezi yegesi ngokuvamile i-millitorr eminingana kuya kumashumi emillitorr, futhi izinga le-ionization lingaphansi kuka-10-5. Kumodi yokukhipha okuhambisana ne-inductively: ngokuvamile ekucindezelweni kwegesi okuphansi (amashumi emillitorr), i-plasma ikhiqizwa futhi igcinwe amandla okufakwayo ahlanganiswe nge-inductively. Izinga le-ionization livame ukuba likhulu kune-10-5, ngakho-ke libizwa nangokuthi i-plasma ephezulu kakhulu. Imithombo ye-plasma ephezulu kakhulu ingatholakala ngokusebenzisa i-electron cyclotron resonance kanye ne-cyclotron wave discharge. I-plasma ene-high-density ingakwazi ukuthuthukisa izinga lokushumeka nokukhetha kwenqubo yokunamathisela kuyilapho inciphisa ukulimala kokufakwayo ngokulawula ngokuzimela ukugeleza kwe-ion namandla ebhomu le-ion ngokusebenzisa i-RF yangaphandle noma amandla kagesi we-microwave kanye nokunikezwa kwamandla okuchelela kwe-RF ku-substrate.
Inqubo eyomile ye-etching ingokulandelayo: igesi yokufaka ijojowe ekamelweni lokuphendula i-vacuum, futhi ngemva kokucindezelwa ekamelweni lokuphendula kuzinzile, i-plasma ikhiqizwa ukukhishwa kokukhanya komsakazo; ngemva kokuthonywa ama-electron anesivinini esikhulu, ayabola ukuze akhiqize ama-radicals mahhala, asakazekela ebusweni be-substrate futhi akhangiswe. Ngaphansi kwesenzo se-ion bombardment, ama-radicals mahhala adsorbed ahlangana nama-athomu noma ama-molecule angaphezulu kwe-substrate ukuze akhe izinto ezikhiqizwa yigesi, eziphuma egumbini lokusabela. Inqubo iboniswa emfanekisweni olandelayo:
Izinqubo zokucwilisa okomile zingahlukaniswa zibe izigaba ezine ezilandelayo:
(1)I-sputtering etching ngokomzimba: Incike kakhulu kuma-ion anamandla ku-plasma ukuze ibhomule ebusweni bento eqoshiwe. Inani lama-athomu ahlakazekile lincike emandleni kanye ne-engeli yezinhlayiya zesigameko. Uma amandla ne-engeli kuhlala kungashintshile, izinga lokufafaza lezinto ezihlukene ngokuvamile lihluka izikhathi ezi-2 kuya kwezi-3 kuphela, ngakho-ke akukho ukukhetha. Inqubo yokusabela ngokuyinhloko i-anisotropic.
(2)Ukufakwa kwamakhemikhali: I-Plasma inikeza ama-athomu e-gas-etching etching kanye nama-molecule, asabela ngamakhemikhali nengaphezulu lezinto ukuze akhiqize amagesi ashintshashintshayo. Lokhu kusabela kwamakhemikhali kuphela kunokukhetha okuhle futhi kubonisa izici ze-isotropic ngaphandle kokucabangela isakhiwo se-lattice.
Isibonelo: Si (okuqinile) + 4F → SiF4 (gaseous), photoresist + O (gaseous) → CO2 (gaseous) + H2O (gaseous)
(3)I-ion energy driven etching: Ama-ion yizinhlayiyana zombili ezidala izinhlayiya ezibambayo neziphethe amandla. Ukusebenza kahle kwezinhlayiya ezinjalo eziphethe amandla kungaphezu kokukodwa kobukhulu obungaphezu kokwenyuka okulula okubonakalayo noma kwamakhemikhali. Phakathi kwazo, ukwenziwa kahle kwamapharamitha angokomzimba namakhemikhali enqubo kuwumgogodla wokulawula inqubo yokuqopha.
(4)I-ion-barrier composite etching: Ngokuyinhloko ibhekisela ekukhiqizeni ungqimba oluvikelayo lwe-polymer ngezinhlayiya eziyinhlanganisela phakathi nenqubo yokufaka. I-Plasma idinga ungqimba olunjalo oluvikelayo ukuvimbela ukusabela kwe-etching of the sidewalls ngesikhathi senqubo yokuqopha. Isibonelo, ukungeza u-C ku-Cl kanye ne-Cl2 etching kungaveza ungqimba oluhlanganisiwe lwe-chlorocarbon ngesikhathi sokunamathisela ukuze kuvikelwe izindonga ezisemaceleni ekuqoshweni.
2.2.1 Ukuhlanza okomile
Ukuhlanza okomile kubhekisela ekuhlanzweni kwe-plasma. Ama-ion kuplasma asetshenziselwa ukuqhumisa ibhomu indawo ukuze ihlanzwe, futhi ama-athomu nama-molecule asesimweni esicushiwe asebenzisana nendawo ukuze ahlanzwe, ukuze kukhishwe futhi kuthuthukiswe i-photoresist. Ngokungafani ne-etching eyomile, imingcele yenqubo yokuhlanza okomile ngokuvamile ayifaki ukukhetha kokuqondisa, ngakho umklamo wenqubo ulula. Ezinqubweni zokukhiqiza ezinkulu, amagesi asekelwe ku-fluorine, umoya-mpilo noma i-hydrogen asetshenziswa ngokuyinhloko njengomzimba oyinhloko we-plasma yokusabela. Ngaphezu kwalokho, ukwengeza inani elithile le-argon plasma kungathuthukisa umphumela we-ion bombardment, ngaleyo ndlela kuthuthukise ukusebenza kahle kokuhlanza.
Enqubweni yokuhlanza okomile kwe-plasma, indlela ye-plasma ekude ivame ukusetshenziswa. Lokhu kungenxa yokuthi enqubweni yokuhlanza, kuthenjwa ukuthi kuzonciphisa umphumela wokuqhunyiswa kwamabhomu we-ion ku-plasma ukulawula umonakalo obangelwa ukuqhuma kwe-ion; kanye nokusabela okuthuthukisiwe kwama-radicals mahhala amakhemikhali kungathuthukisa ukusebenza kahle kokuhlanza. I-plasma yesilawuli kude ingasebenzisa ama-microwave ukuze ikhiqize i-plasma ezinzile futhi enomthamo omkhulu ngaphandle kwegumbi lokusabela, ikhiqize inani elikhulu lama-radicals amahhala angena egumbini lokusabela ukuze kuzuzwe ukusabela okudingekayo ekuhlanzeni. Iningi lemithombo yegesi yokuhlanza okomile embonini isebenzisa amagesi asekelwe ku-fluorine, njenge-NF3, futhi ngaphezu kwe-99% ye-NF3 iboliswa ku-microwave plasma. Cishe awukho umphumela we-ion bombardment enqubweni yokuhlanza okomile, ngakho-ke kuyazuzisa ukuvikela iwafa ye-silicon emonakalweni nokwelula impilo yegumbi lokusabela.
Imishini emithathu yokufaka emanzi kanye nokuhlanza
3.1 Umshini wokuhlanza iwafa wohlobo lwethangi
Umshini wokuhlanza i-wafer wohlobo lwe-trough ikakhulukazi wakhiwe imodyuli yokudlulisa ibhokisi le-wafer elivula ngaphambili, imojula yokuhambisa i-wafer / ukulayisha, imojula yokukhipha umoya, imojula yethangi lamakhemikhali amakhemikhali, imojula yethangi lamanzi e-deionized, ithangi lokumisa. module kanye nemojuli yokulawula. Ingakwazi ukuhlanza amabhokisi amaningi wamawafa ngesikhathi esisodwa futhi ingafinyelela amawafa omile futhi ome.
3.2 I-Trench Wafer Etcher
3.3 Isisetshenziswa Sokucubungula Esimanzi Esisodwa
Ngokwezinjongo ezihlukene zenqubo, imishini yenqubo ye-wafer wet eyodwa ingahlukaniswa izigaba ezintathu. Isigaba sokuqala yimishini yokuhlanza i-wafer eyodwa, izinhloso zayo zokuhlanza zihlanganisa izinhlayiya, izinto eziphilayo, ungqimba lwe-oxide yemvelo, ukungcola kwensimbi nokunye ukungcola; isigaba sesibili imishini yokukhuhla eyilucwecwana eyodwa, injongo yayo eyinhloko iwukukhipha izinhlayiya ebusweni bewafa; isigaba sesithathu i-single-wafer etching equipment, esetshenziswa kakhulu ukususa amafilimu amancane. Ngokwezinjongo ezihlukene zenqubo, umshini wokuthunga we-wafer owodwa ungahlukaniswa ube izinhlobo ezimbili. Uhlobo lokuqala luyimishini yokufaka i-mild etching, esetshenziswa kakhulu ukususa izingqimba zokulimala kwefilimu engaphezulu okubangelwa ukufakwa kwe-ion enamandla amakhulu; uhlobo lwesibili yimishini yokususa ungqimba yomhlatshelo, esetshenziswa kakhulu ukususa izingqimba zokuvimbela ngemva kokuncipha kwe-wafer noma ukupholisha ngamakhemikhali.
Ngokombono wesakhiwo somshini wonke, ukwakheka okuyisisekelo kwazo zonke izinhlobo zemishini yenqubo emanzi eyisicwecwana esisodwa iyefana, ngokuvamile ehlanganisa izingxenye eziyisithupha: uhlaka oluyinhloko, uhlelo lokudlulisa oluyisicwecwana, imojula yegumbi, ukuhlinzekwa koketshezi lwamakhemikhali kanye nemojula yokudlulisa, uhlelo lwesofthiwe. kanye nemojula yokulawula ye-elekthronikhi.
3.4 Izisetshenziswa Zokuhlanza Iwafa Eyodwa
Imishini yokuhlanza i-wafer eyodwa iklanyelwe ngokusekelwe endleleni yokuhlanza ye-RCA yendabuko, futhi inhloso yayo yenqubo ukuhlanza izinhlayiya, izinto eziphilayo, ungqimba lwe-oxide yemvelo, ukungcola kwensimbi nokunye ukungcola. Ngokusetshenziswa kwenqubo, imishini yokuhlanza i-wafer eyodwa okwamanje isetshenziswa kabanzi ezinqubweni zangaphambili nangemuva zokwenziwa kwesekethe edidiyelwe, okuhlanganisa ukuhlanza ngaphambi nangemva kokwakhiwa kwefilimu, ukuhlanza ngemva kokucwiliswa kwe-plasma, ukuhlanza ngemva kokufakwa kwe-ion, ukuhlanza ngemva kwamakhemikhali. ukupholisha ngomshini, nokuhlanza ngemva kokufakwa kwensimbi. Ngaphandle kwenqubo yokushisa ephezulu ye-phosphoric acid, imishini yokuhlanza i-wafer eyodwa ngokuyisisekelo iyahambisana nazo zonke izinqubo zokuhlanza.
3.5 Isisetshenziswa Sokuhlanganisa Iwafa Esodwa
Inhloso yenqubo yemishini yokunamathisela isinkwa esilucwecwana esisodwa ikakhulukazi ukuqoshwa kwefilimu emincane. Ngokwenhloso yenqubo, ingahlukaniswa ngezigaba ezimbili, okungukuthi, imishini yokufaka ukukhanya (esetshenziselwa ukususa ungqimba lomonakalo wefilimu obangelwa ukufakwa kwe-ion ene-energy ephezulu) kanye nemishini yokukhipha ungqimba yomhlatshelo (esetshenziselwa ukususa ungqimba oluyisithiyo ngemuva kwe-wafer. ukucwebezela noma ukupholisha amakhemikhali). Izinto ezidinga ukususwa kule nqubo ngokuvamile zihlanganisa i-silicon, i-silicon oxide, i-silicon nitride nezingqimba zefilimu yensimbi.
Imishini yokuhlanza emine eyomile
4.1 Ukuhlelwa kwemishini yokufaka i-plasma
Ngokungeziwe kumishini yokufaka i-ion sputtering eseduze nokusabela okungokoqobo ngokomzimba kanye nemishini yokukhipha amanzi eseduze nokusabela kwamakhemikhali ahlanzekile, ukufakwa kwe-plasma kungahlukaniswa cishe izigaba ezimbili ngokuya ngobuchwepheshe obuhlukahlukene bokukhiqiza i-plasma nokulawula:
-Ukufakwa kwe-Capacitively Coupled Plasma (CCP);
-I-Inductively Coupled Plasma (ICP) etching.
4.1.1 CCP
Ukufakwa kwe-plasma okuhlanganiswe ngokunamandla kuwukuxhuma amandla efrikhwensi yomsakazo eyodwa noma womabili ama-electrode aphezulu naphansi egumbini lokusabela, futhi i-plasma ephakathi kwamapuleti amabili yakha i-capacitor kusekethe efanayo enziwe lula.
Kunobuchwepheshe obunjalo bokuqala ababili:
Enye i-plasma etching yakuqala, exhuma amandla e-RF ku-electrode ephezulu kanye ne-electrode engezansi lapho i-wafer ibekwe khona. Ngenxa yokuthi i-plasma ekhiqizwe ngale ndlela ngeke yakhe umgodla we-ion owugqinsi ngokwanele ebusweni bewafa, amandla e-ion bombardment aphansi, futhi ngokuvamile asetshenziswa ezinqubweni ezifana nokucwiliswa kwe-silicon ezisebenzisa izinhlayiya ezisebenzayo njenge-etchant eyinhloko.
Enye i-etching ion etching (RIE) yokuqala esebenzayo, exhuma amandla e-RF ku-electrode ephansi lapho i-wafer ikhona, futhi igxilise i-electrode engaphezulu ngendawo enkulu. Lobu buchwepheshe bungakha igobolondo le-ion elijiyile, elifanele izinqubo zokufaka i-dielectric ezidinga amandla e-ion aphezulu ukuze abambe iqhaza ekuphenduleni. Ngokwesisekelo sokushumeka kwe-ion esebenzayo kwangaphambi kwesikhathi, inkambu kazibuthe ye-DC eqondane nenkundla kagesi ye-RF yengezwa ukwenza i-ExB drift, engakhuphula ithuba lokushayisana kwama-electron nezinhlayiya zegesi, ngaleyo ndlela kuthuthukiswe ngempumelelo ukugxiliswa kwe-plasma nezinga lokuxhuma. Le etching ibizwa ngokuthi i-magnetic field enhanced reactive ion etching (MERIE).
Ubuchwepheshe obuthathu obungenhla bunobubi obuvamile, okungukuthi, ukugxila kwe-plasma namandla ayo akukwazi ukulawulwa ngokwehlukana. Isibonelo, ukuze kwandiswe izinga lokushaya, indlela yokwandisa amandla e-RF ingasetshenziswa ukukhulisa ukugxila kwe-plasma, kodwa amandla e-RF akhuphukayo azoholela nakanjani ekwenyukeni kwamandla e-ion, okuzodala umonakalo kumadivayisi avuliwe. isicwecwana. Kule minyaka eyishumi edlule, ubuchwepheshe bokuhlanganisa i-capacitive buye bamukela idizayini yemithombo eminingi ye-RF, exhunywe kuma-electrode aphezulu naphansi ngokulandelanayo noma kokubili ku-electrode ephansi.
Ngokukhetha nokumatanisa amafrikhwensi e-RF ahlukene, indawo yama-electrode, isikhala, izinto zokwakha kanye neminye imingcele ebalulekile kuhlanganiswa nomunye nomunye, ukugxiliswa kwe-plasma namandla e-ion kungahlukaniswa ngangokunokwenzeka.
4.1.2 I-ICP
Ukufakwa kwe-plasma okuhlanganiswe ngendlela ehambisanayo ukubeka isethi eyodwa noma amaningi amakhoyili axhunywe kugesi wefrikhwensi yomsakazo phezu noma eduze negumbi lokusabela. Inkambu kazibuthe eshintshanayo ekhiqizwa amaza omsakazo womsakazo ikhoyili ingena egumbini lokusabela ngefasitela le-dielectric ukuze isheshise ama-electron, ngaleyo ndlela ikhiqize i-plasma. Kumjikelezo olinganayo owenziwe lula (i-transformer), ikhoyili iyi-inductance yokumayo eyinhloko, futhi i-plasma iyi-inductance yesibili emazombezombe.
Le ndlela yokuhlanganisa ingakwazi ukuzuza ukuhlushwa kwe-plasma okungaphezu kwe-oda elilodwa lobukhulu ngaphezu kokuhlanganisa i-capacitive ngengcindezi ephansi. Ngaphezu kwalokho, ugesi wesibili we-RF uxhunywe endaweni yewafa njengomthombo wamandla ochemile ukuze unikeze amandla e-ion bombardment. Ngakho-ke, ukugxiliswa kwe-ion kuncike ekunikezeni amandla omthombo wekhoyili namandla e-ion ancike ekunikezeni kwamandla okuchemile, ngaleyo ndlela kuzuzwe ukuhlukaniswa okuphelele kakhulu kokugxila namandla.
4.2 Izisetshenziswa zokuhlanganisa i-Plasma
Cishe wonke ama-etchants ku-etching eyomile akhiqizwa ngokuqondile noma ngokungaqondile kusuka ku-plasma, ngakho ukufakwa okomile kuvame ukubizwa ngokuthi i-plasma etching. I-Plasma etching iwuhlobo lwe-plasma etching ngomqondo obanzi. Emiklamweni emibili yokuqala yokuqala ye-flat-plate reactor, enye iwukugaya ipuleti lapho i-wafer ikhona kanti elinye ipuleti lixhunywe kumthombo we-RF; enye iphambene. Kumklamo wangaphambili, indawo yepuleti eliphansi ngokuvamile inkulu kunendawo yepuleti elixhunywe kumthombo we-RF, futhi umfutho wegesi kureactor uphezulu. Igobolondo le-ion elakhiwe ebusweni be-wafer lincane kakhulu, futhi i-wafer ibonakala "icwiliswe" ku-plasma. I-Etching iqedwa ngokuyinhloko ukusabela kwamakhemikhali phakathi kwezinhlayiya ezisebenzayo ku-plasma kanye nobuso bezinto eziqoshiwe. Amandla e-ion bombardment mancane kakhulu, futhi ukubamba iqhaza kwawo ekucupheni kuphansi kakhulu. Lo mklamo ubizwa nge-plasma etching mode. Komunye umklamo, ngenxa yokuthi izinga lokubamba iqhaza kwe-ion bombardment likhulu uma kuqhathaniswa, libizwa ngemodi yokushumeka kwe-ion esebenzayo.
4.3 Isisetshenziswa Sokuhlanganisa Ion Esisebenzayo
I-Reactive ion etching (RIE) ibhekisela enqubweni yokuhlanganisa lapho izinhlayiya ezisebenzayo nama-ion ashajiwe abamba iqhaza enqubweni ngesikhathi esifanayo. Phakathi kwazo, izinhlayiya ezisebenzayo ikakhulukazi ziyizinhlayiya ezingathathi hlangothi (ezaziwa nangokuthi ama-radicals mahhala), ezinokugxila okuphezulu (cishe u-1% kuya ku-10% wegesi lokuhlushwa), okuyizingxenye eziyinhloko ze-etchant. Imikhiqizo ekhiqizwe ukusabela kwamakhemikhali phakathi kwayo nezinto ezigxilile kungenzeka ivuthelwe amandla futhi ikhishwe ngokuqondile egumbini lokusabela, noma iqoqwe endaweni eqoshiwe; kuyilapho ama-ion akhokhiswayo esezingeni eliphansi lokuhlushwa (10-4 kuya ku-10-3 yokuhlushwa kwegesi), futhi asheshiswa inkambu kagesi ye-ion sheath eyakhiwe ebusweni be-wafer ukuze ibhomule indawo eqoshiwe. Kunemisebenzi emibili eyinhloko yezinhlayiya ezishajiwe. Enye iwukubhubhisa ukwakheka kwe-athomu yento eqoshiwe, ngaleyo ndlela kusheshiswe izinga lapho izinhlayiya ezisebenzayo zisabela ngayo; enye iwukuba ibhomu futhi isuse imikhiqizo yokusabela eqoqiwe ukuze izinto eziqoshiwe zithintane ngokugcwele nezinhlayiya ezisebenzayo, ukuze ukugxila kuqhubeke.
Ngenxa yokuthi ama-ion awabambi iqhaza ngokuqondile ekusabeleni kokuhlaba (noma kulandisa ingxenye encane kakhulu, njengokususwa kwebhomu kanye nokushumeka kwamakhemikhali okuqondile kwama-ion asebenzayo), uma sikhuluma nje, inqubo yokubophela engenhla kufanele ibizwe ngokuthi i-ion-assisted etching. Igama elithi reactive ion etching alinembile, kodwa lisasetshenziswa nanamuhla. Imishini yokuqala ye-RIE yasetshenziswa ngawo-1980. Ngenxa yokusetshenziswa kwamandla kagesi e-RF eyodwa kanye nesakhiwo esilula segumbi lokusabela, inomkhawulo mayelana nesilinganiso sokuhlanganisa, ukufana nokukhetha.
4.4 Isisetshenziswa Sokushumeka Se-Ion Esebenzayo Esithuthukisiwe
Idivayisi ye-MERIE (Magnetically Enhanced Reactive Ion Etching) iyisisetshenziswa sokufaka esakhiwe ngokwengeza indawo kazibuthe ye-DC kudivayisi ye-RIE yephaneli eyisicaba futhi kuhloswe ngayo ukukhulisa izinga lokunamathisela.
Imishini ye-MERIE yasetshenziswa ngezinga elikhulu ngeminyaka yawo-1990, lapho okokunamathisela ngewafa okukodwa kwase kuba amathuluzi ajwayelekile embonini. Ububi obukhulu bezinto zokusebenza ze-MERIE ukuthi ukusatshalaliswa kwe-spapatial inhomogeneity yokugxiliswa kwe-plasma okubangelwa indawo kazibuthe kuzoholela ekwehlukeni kwamanje noma kwe-voltage kudivayisi yesekethe ehlanganisiwe, ngaleyo ndlela kubangele ukulimala kwedivayisi. Njengoba lo monakalo ubangelwa inhomogeneity esheshayo, ukujikeleza kwendawo kazibuthe akukwazi ukukuqeda. Njengoba usayizi wamasekhethi ahlanganisiwe uqhubeka nokuncipha, ukulimala kwedivayisi yabo kuya ngokuya kuzwela ku-plasma inhomogeneity, futhi ubuchwepheshe bokukhulisa izinga lokunamathisela ngokuthuthukisa amandla kazibuthe buye bathathelwa indawo ubuchwepheshe obuhlanganisa amandla kagesi we-RF amaningi asebenzayo we-ion etching, lokho ubuchwepheshe obuhlanganiswe ngokunamandla be-plasma etching.
4.5 Imishini yokuhlanganisa i-plasma ehlanganiswe kahle
I-Capacitively coupled plasma (CCP) imishini yokuhlanganisa i-plasma (CCP) iyithuluzi elikhiqiza i-plasma egumbini lokusabela ngokusebenzisa i-capacitive coupling ngokusebenzisa ifrikhwensi yomsakazo (noma i-DC) amandla okunikezwa kwamandla epuleti lika-electrode futhi isetshenziselwa ukushumeka. Umgomo wayo wokufaka uyafana nalowo wemishini yokushumeka ye-ion esebenzayo.
Umdwebo owenziwe lula we-CCP etching umdwebo uboniswa ngezansi. Ivamise ukusebenzisa imithombo ye-RF emibili noma emithathu yamafrikhwensi ahlukene, kanti eminye isebenzisa amandla kagesi e-DC. Imvamisa yokunikezwa kwamandla e-RF ngu-800kHz~162MHz, futhi asetshenziswa kakhulu ngu-2MHz, 4MHz, 13MHz, 27MHz, 40MHz kanye no-60MHz. Izinsiza zamandla e-RF ezinefrikhwensi engu-2MHz noma 4MHz zivame ukubizwa ngemithombo ye-RF ye-low-frequency. Ngokuvamile zixhunywe ku-electrode ephansi lapho i-wafer ikhona. Zisebenza kahle kakhulu ekulawuleni amandla e-ion, ngakho-ke zibizwa nangokuthi i-bias power supply; Amandla kagesi e-RF ane-frequency engaphezu kuka-27MHz abizwa ngemithombo ye-high-frequency RF. Zingaxhunywa ku-electrode ephezulu noma i-electrode ephansi. Zisebenza kahle kakhulu ekulawuleni ukugxiliswa kwe-plasma, ngakho-ke zibizwa nangokuthi imithombo yamandla omthombo. Ukunikezwa kwamandla kwe-13MHz RF kumaphakathi futhi ngokuvamile kubhekwa njengokunayo yomibili le misebenzi engenhla kodwa ibuthakathaka ngokuqhathaniswa. Qaphela ukuthi nakuba ukugxiliswa kwe-plasma namandla kungalungiswa phakathi kwebanga elithile ngamandla emithombo ye-RF yamafrikhwensi ahlukene (lokho okubizwa ngokuthi umphumela wokuqhafaza), ngenxa yezimpawu ze-capacitive coupling, azikwazi ukulungiswa nokulawulwa ngokuzimela ngokuphelele.
Ukusatshalaliswa kwamandla kwama-ion kunomthelela omkhulu ekusebenzeni okuningiliziwe kokucupha kanye nokulimala kwedivayisi, ngakho-ke ukuthuthukiswa kobuchwepheshe bokuthuthukisa ukusatshalaliswa kwamandla e-ion sekube ngelinye lamaphuzu abalulekile emishini yokuqopha ethuthukisiwe. Njengamanje, ubuchwepheshe obusetshenziswe ngempumelelo ekukhiqizeni buhlanganisa i-multi-RF hybrid drive, i-DC superposition, i-RF ehlanganiswe ne-DC pulse bias, kanye nokuphuma kwe-RF okuhambisanayo kokuphakelayo kwamandla kanye nokunikezwa kwamandla omthombo.
Imishini yokufaka i-CCP ingenye yezinhlobo ezimbili ezisetshenziswa kakhulu zemishini yokuhlanganisa i-plasma. Isetshenziswa kakhulu enqubweni yokufaka izinto ze-dielectric, njengodonga oluseceleni kwesango kanye ne-hard mask etching esigabeni esingaphambili senqubo ye-logic chip, ukushumeka kwembobo yokuxhumana esiteji esiphakathi, i-mosaic kanye ne-aluminium etching ngemuva kwesiteji, kanye ukufakwa kwemisele ejulile, izimbobo ezijulile kanye nezimbobo zokuxhumana zezintambo kunqubo ye-chip memory ye-3D (kuthatha isakhiwo se-silicon nitride/silicon oxide njengesibonelo).
Kunezinselelo ezimbili eziyinhloko kanye nezikhombisi-ndlela zokuthuthukisa ezibhekene nemishini yokubhala ye-CCP. Okokuqala, ekusetshenzisweni kwamandla e-ion aphezulu kakhulu, amandla okuhlanganisa wezakhiwo ze-aspect ratio (ezifana nembobo nokushumeka komgodi wememori ye-3D flash kudinga isilinganiso esiphezulu kuno-50:1). Indlela yamanje yokukhulisa amandla okuchema ukuze kukhuliswe amandla e-ion isebenzise amandla kagesi e-RF afika kuma-watts angu-10,000. Uma kubhekwa inani elikhulu lokushisa okukhiqizwayo, ubuchwepheshe bokupholisa nokulawula izinga lokushisa kwekamelo lokusabela budinga ukuthuthukiswa ngokuqhubekayo. Okwesibili, kudingeka kube nenqubekelaphambili ekuthuthukisweni kwamagesi amasha e-etching ukuze kuxazululwe ngokuyisisekelo inkinga yekhono lokushumeka.
4.6 Izisetshenziswa Zokuhlanganisa I-Plasma Ezihlanganisiwe
I-Inductively coupled plasma (ICP) etching equipment iyisisetshenziswa esihlanganisa amandla omthombo wamandla wefrikhwensi yomsakazo sibe yigumbi lokusabela ngendlela yenkundla kazibuthe ngekhoyili ye-inductor, ngaleyo ndlela ikhiqize i-plasma yokushumeka. Isimiso saso sokufaka i-etching siphinde sibe se-generalized reactive ion etching.
Kunezinhlobo ezimbili eziyinhloko zemiklamo yomthombo we-plasma yemishini yokufaka i-ICP. Enye ubuchwepheshe be-transformer ehlanganisiwe ye-plasma (TCP) eyakhiwe futhi yakhiqizwa yiLam Research. Ikhoyili yayo ye-inductor ibekwe endizeni yefasitela le-dielectric ngaphezu kwegumbi lokusabela. Isiginali ye-RF engu-13.56MHz ikhiqiza inkambu kazibuthe eshintshanayo kukhoyili eqondane newindi le-dielectric futhi ihlukana ngokukhazimulayo nge-eksisi yekhoyili njemaphakathi.
Indawo kazibuthe ingena egunjini lokusabela ngefasitela le-dielectric, futhi inkambu kazibuthe eshintshanayo ikhiqiza inkambu kagesi eshintshanayo ehambisana nefasitela le-dielectric egumbini lokusabela, ngaleyo ndlela kuzuzwe ukuhlukaniswa kwegesi ebambayo futhi ikhiqize i-plasma. Njengoba lesi simiso singaqondwa njengesiguquli esinekhoyili ye-inductor njengokusonga okuyinhloko kanye ne-plasma egunjini lokusabela njengokujika kwesibili, ukufakwa kwe-ICP kuqanjwe ngaleli.
Inzuzo enkulu yobuchwepheshe be-TCP ukuthi isakhiwo kulula ukukhuphula. Isibonelo, kusukela ku-wafer engu-200mm kuya ku-wafer engu-300mm, i-TCP ingagcina umphumela ofanayo wokunamathisela ngokumane ikhulise usayizi wekhoyili.
Omunye umklamo womthombo we-plasma ubuchwepheshe bomthombo we-plasma obuhlanganisiwe (i-DPS) owenziwe futhi wakhiqizwa yi-Applied Materials, Inc. yase-United States. Ikhoyili yayo ye-inductor inamanxeba amathathu-ntathu efasiteleni le-dielectric ene-hemispherical. Umgomo wokukhiqiza i-plasma ufana nobuchwepheshe be-TCP okukhulunywe ngabo ngenhla, kodwa ukusebenza kahle kokuhlukaniswa kwegesi kuphakeme kakhulu, okulungele ukuthola ukuhlushwa okuphezulu kwe-plasma.
Njengoba ukusebenza kahle kwe-inductive coupling ukukhiqiza i-plasma kungaphezulu kwalokho kwe-capacitive coupling, futhi i-plasma ikhiqizwa ikakhulukazi endaweni eseduze nefasitela le-dielectric, ukugxila kwayo ku-plasma kunqunywa ngokuyisisekelo amandla omthombo wamandla oxhunywe ku-inductor. ikhoyili, namandla e-ion emgodleni we-ion ebusweni bewafa ngokuyisisekelo kunqunywa amandla okunikezwa kwamandla okuchemile, ngakho ukugxila namandla ama-ion. ingalawulwa ngokuzimela, ngaleyo ndlela izuze ukuhlukaniswa.
Imishini yokufaka i-ICP ingenye yezinhlobo ezimbili ezisetshenziswa kakhulu zemishini yokufaka i-plasma. Isetshenziselwa ikakhulukazi ukunamathisela imisele ye-silicon engashoni, i-germanium (Ge), izakhiwo zesango le-polysilicon, izakhiwo zesango lensimbi, i-silicon ehlutshiwe (i-Strained-Si), izintambo zensimbi, izinsimbi zensimbi (amaPads), imaski eqinile ye-mosaic kanye nezinqubo eziningi ubuchwepheshe bezithombe eziningi.
Ngaphezu kwalokho, ngokukhuphuka kwamasekethe ahlanganisiwe anezinhlangothi ezintathu, izinzwa zesithombe ze-CMOS kanye nezinhlelo ezincane ze-electro-mechanical (MEMS), kanye nokwanda okusheshayo kokusetshenziswa kwe-silicon vias (TSV), izimbobo ezinkulu ezitshekile kanye i-silicone etching ejulile ene-morphology ehlukene, abakhiqizi abaningi bethule imishini yokufaka eyakhelwe ngokukhethekile lezi zinhlelo zokusebenza. Izici zayo ziwukujula okukhulu kwe-etching (amashumi noma amakhulu ama-microns), ngakho-ke isebenza kakhulu ngaphansi kokugeleza kwegesi ephezulu, ukucindezela okuphezulu nezimo zamandla aphezulu.
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Isikhathi sokuthumela: Aug-31-2024