Isimo Samanje kanye Nemikhuba Yobuchwepheshe Bokucubungula I-SiC Wafer

Njengezinto ze-substrate zesizukulwane sesithathu ze-semiconductor,i-silicon carbide (i-SiC)I-crystal eyodwa inamathuba amaningi okusetshenziswa ekukhiqizweni kwamadivayisi kagesi asebenza ngesivinini esikhulu nangamandla aphezulu. Ubuchwepheshe bokucubungula be-SiC budlala indima ebalulekile ekukhiqizweni kwezinto ezisezingeni eliphezulu ze-substrate. Lesi sihloko sethula isimo samanje socwaningo ngobuchwepheshe bokucubungula i-SiC kokubili eShayina nakwamanye amazwe, sihlaziya futhi siqhathanisa izindlela zokusika, ukugaya, kanye nokupholisha izinqubo, kanye nezitayela zokusicaba kwe-wafer kanye nokungalungi kobuso. Siphinde siveze izinselele ezikhona ekucutshungulweni kwe-wafer ye-SiC futhi sixoxe ngeziqondiso zentuthuko yesikhathi esizayo.

I-silicon carbide (i-SiC)Ama-wafer ayizinto ezibalulekile eziyisisekelo zamadivayisi e-semiconductor esizukulwane sesithathu futhi abaluleke kakhulu futhi anamandla emakethe emikhakheni efana ne-microelectronics, i-power electronics, kanye nokukhanyisa kwe-semiconductor. Ngenxa yobunzima obuphezulu kakhulu kanye nokuqina kwamakhemikhaliAmakristalu angawodwa e-SiC, izindlela zokucubungula zendabuko ze-semiconductor azifaneleki ngokuphelele ekusetshenzisweni kwazo. Nakuba izinkampani eziningi zamazwe ngamazwe zenze ucwaningo olunzulu mayelana nokucutshungulwa okudinga ubuchwepheshe kwamakristalu angawodwa e-SiC, ubuchwepheshe obufanele bugcinwa buyimfihlo ngokuphelele.

Eminyakeni yamuva nje, iShayina ikhulise imizamo ekuthuthukiseni izinto namadivayisi e-SiC single crystal. Kodwa-ke, ukuthuthuka kobuchwepheshe bedivayisi ye-SiC ezweni okwamanje kuvinjelwe yimikhawulo yobuchwepheshe bokucubungula kanye nekhwalithi ye-wafer. Ngakho-ke, kubalulekile ukuthi iShayina ithuthukise amakhono okucubungula i-SiC ukuze ithuthukise ikhwalithi ye-SiC single crystal substrates futhi ifeze ukusetshenziswa kwayo okusebenzayo kanye nokukhiqizwa kwayo ngobuningi.

Izinyathelo eziyinhloko zokucubungula zifaka: ukusika → ukugaya okuqinile → ukugaya kahle → ukupholisha okuqinile (ukupholisha ngomshini) → ukupholisha kahle (ukupholisha ngomshini kwamakhemikhali, i-CMP) → ukuhlolwa.

Ukusikwa Kwamakristalu Angawodwa e-SiC

Ekucutshungulweni kweAmakristalu angawodwa e-SiC, ukusika kuyisinyathelo sokuqala nesibaluleke kakhulu. Ukwehluka kobukhulu be-wafer's bow, i-warp, kanye ne-total thickness (TTV) okuvela enkambisweni yokusika kunquma ikhwalithi kanye nokusebenza kahle kwemisebenzi yokugaya nokupholisha elandelayo.

Amathuluzi okusika angahlukaniswa ngesimo sibe ngamasaha edayimane angaphakathi (ID), amasoha edayimane angaphandle (OD), amasoha ebhendi, kanye namasaha ensimbi. Amasaha ensimbi, wona, angahlukaniswa ngohlobo lwawo lokunyakaza abe izinhlelo zensimbi eziphindaphindayo neziyindilinga (ezingenamkhawulo). Ngokusekelwe endleleni yokusika ye-abrasive, amasu okusika ngensimbi angahlukaniswa abe izinhlobo ezimbili: ukusaha ngentambo okukhululekile kanye nokusaha ngentambo yedayimane okuqinile okuqinile.

1.1 Izindlela Zokusika Zendabuko

Ukujula kokusika kwamasaha angaphandle anobubanzi (OD) kunqunyelwe ububanzi be-blade. Ngesikhathi senqubo yokusika, i-blade ithambekele ekudlidlizeni nasekuphambukeni, okuholela emazingeni aphezulu omsindo kanye nokuqina okungekuhle. Amasaha angaphakathi anobubanzi (ID) asebenzisa ama-brasive edayimane engxenyeni yangaphakathi ye-blade njengomphetho wokusika. Lawa ma-blade angaba mancane njengo-0.2 mm. Ngesikhathi sokusika, i-ID blade ijikeleza ngesivinini esikhulu kuyilapho izinto ezizosikwa zihamba ngokushelela maqondana nesikhungo se-blade, zifinyelela ekusikeni ngale ntshukumo ehlobene.

Amasaha e-diamond band adinga ukuma njalo nokuguqulwa, futhi isivinini sokusika siphansi kakhulu—ngokuvamile singadluli ama-2 m/s. Aphinde ahlupheke ngokuguguleka okukhulu kwemishini kanye nezindleko eziphezulu zokulungisa. Ngenxa yobubanzi be-blade yesaha, i-radius yokusika ayikwazi ukuba ncane kakhulu, futhi ukusika izingcezu eziningi akunakwenzeka. Lawa mathuluzi okusaha endabuko anqunyelwe ukuqina kwesisekelo futhi awakwazi ukwenza ukusika okugobile noma abe ne-radii yokujika ekhawulelwe. Akwazi ukusika okuqondile kuphela, akhiqize ama-kerf abanzi, abe nesilinganiso esiphansi sokuvunwa, ngakho-ke awafaneleki ukusika.Amakristalu e-SiC.

1.2 Ukusika Izintambo Eziningi Ezine-Abrasive Wire Saw Yamahhala

Indlela yokusika insimbi e-abrasive yamahhala isebenzisa ukunyakaza okusheshayo kwentambo ukuze ithwale udaka iye e-kerf, okwenza kube lula ukususa izinto. Ngokuyinhloko isebenzisa isakhiwo esibuyiselanayo futhi okwamanje iyindlela evuthiwe nesetshenziswa kabanzi yokusika i-silicon enekristalu elilodwa nge-wafer ephumelelayo. Kodwa-ke, ukusetshenziswa kwayo ekusikeni kwe-SiC akukafundwa kabanzi.

Ama-wire saw abrasive amahhala angacubungula ama-wafer anobukhulu obungaphansi kwama-300 μm. Anikeza ukulahleka okuphansi kwe-kerf, akuvamile ukubangela ukuqhekeka, futhi kuholele ekhwalithini enhle kakhulu ebusweni. Kodwa-ke, ngenxa yendlela yokususa izinto—ngokusekelwe ekugoqweni nasekufakweni kwama-abrasives—ubuso be-wafer buvame ukuthuthukisa ukucindezeleka okukhulu okusele, imifantu emincane, kanye nezendlalelo zomonakalo ojulile. Lokhu kuholela ekugoqweni kwe-wafer, kwenza kube nzima ukulawula ukunemba kwephrofayili yobuso, futhi kwandisa umthwalo ezinyathelweni zokucubungula ezilandelayo.

Ukusebenza kokusika kuthonywa kakhulu yi-slurry; kubalulekile ukugcina ubukhali be-abrasives kanye nokuhlushwa kwe-slurry. Ukwelashwa kwe-slurry kanye nokuvuselela kuyabiza. Lapho usika ama-ingot amakhulu, ama-abrasives anobunzima bokungena ema-kerf ajulile nawade. Ngaphansi kobukhulu obufanayo be-abrasive grain, ukulahlekelwa kwe-kerf kukhulu kunokwamasosi e-wire abrasive aqinile.

1.3 Ukusika Okunezintambo Eziningi Okungaguquki Kwe-Abrasive Diamond Wire Saw

Amasaha ensimbi e-abrasive aqinile ngokuvamile enziwa ngokufaka izinhlayiya zedayimane ku-substrate yensimbi ngokusebenzisa izindlela zokubopha nge-electroplating, sintering, noma resin. Amasaha ensimbi e-diamond ahlanganiswe nge-electroplated anikeza izinzuzo ezifana nama-kerf amancane, ikhwalithi engcono yokusika, ukusebenza kahle okuphezulu, ukungcola okuphansi, kanye nekhono lokusika izinto ezinobulukhuni obukhulu.

I-reciprocating electroplated diamond wire saw okwamanje iyindlela esetshenziswa kakhulu yokusika i-SiC. Isithombe 1 (esingaboniswa lapha) sibonisa ukuthamba komphezulu wama-wafer e-SiC asikiwe kusetshenziswa le ndlela. Njengoba ukusika kuqhubeka, i-wafer warpage iyanda. Lokhu kungenxa yokuthi indawo yokuxhumana phakathi kwentambo nezinto ezisetshenziswayo iyanda njengoba intambo ihla, okwandisa ukumelana nokudlidliza kwentambo. Lapho intambo ifinyelela ububanzi obukhulu be-wafer, ukudlidliza kuba seqophelweni eliphezulu, okuholela ekulweni okuphezulu.

Ezigabeni zakamuva zokusikwa, ngenxa yokuthi ucingo lushesha, luhamba ngesivinini esizinzile, luyancipha, luyeka, futhi lubuyela emuva, kanye nobunzima bokususa udoti nge-coolant, ikhwalithi yobuso be-wafer iyawohloka. Ukuguquguquka kocingo kanye nokuguquguquka kwesivinini, kanye nezinhlayiya ezinkulu zedayimane ocingweni, yizona zimbangela eziyinhloko zokuklwebheka kobuso.

1.4 Ubuchwepheshe Bokuhlukana Okubandayo

Ukuhlukaniswa okubandayo kwamakristalu angawodwa e-SiC kuyinqubo entsha emkhakheni wokucubungula izinto ze-semiconductor zesizukulwane sesithathu. Eminyakeni yamuva nje, kuye kwaheha ukunaka okukhulu ngenxa yezinzuzo zayo eziphawulekayo ekuthuthukiseni isivuno kanye nokunciphisa ukulahleka kwezinto. Ubuchwepheshe bungahlaziywa kusukela ezicini ezintathu: isimiso sokusebenza, ukugeleza kwenqubo, kanye nezinzuzo eziyinhloko.

Ukunqunywa Kokuqondiswa Kwekristalu Nokugaya Ububanzi Bangaphandle: Ngaphambi kokucubungula, ukuqondiswa kwekristalu kwe-SiC ingot kumele kunqunywe. I-ingot ibe isibunjwa ibe yisakhiwo esiyisilinda (esivame ukubizwa ngokuthi i-SiC puck) ngokugaya ububanzi bangaphandle. Lesi sinyathelo sibeka isisekelo sokusika nokusika okulandelayo.

Ukusika Ngezintambo Eziningi: Le ndlela isebenzisa izinhlayiya ezihudulayo ezihlanganiswe nezintambo zokusika ukuze zisike i-ingot esilinda. Kodwa-ke, ihlushwa ukulahlekelwa okukhulu kwe-kerf kanye nezinkinga zokungalingani komphezulu.

Ubuchwepheshe Bokusika Nge-Laser: I-laser isetshenziselwa ukwakha ungqimba oluguquliwe ngaphakathi kwekristalu, lapho izingcezu ezincane zingasuswa khona. Le ndlela inciphisa ukulahleka kwezinto futhi ithuthukisa ukusebenza kahle kokucubungula, okwenza kube yindlela entsha ethembisayo yokusika i-wafer ye-SiC.

Ukuthuthukisa Inqubo Yokusika

Ukusika Okunezintambo Eziningi Okungaguquki: Lobu ubuchwepheshe obujwayelekile njengamanje, obufanelekela kahle izici zobulukhuni obuphezulu be-SiC.

Umshini Wokukhipha Ugesi (i-EDM) kanye Nobuchwepheshe Bokuhlukanisa Okubandayo: Lezi zindlela zinikeza izixazululo ezahlukahlukene ezenzelwe izidingo ezithile.

Inqubo Yokupholisha: Kubalulekile ukulinganisela izinga lokususwa kwezinto kanye nomonakalo womphezulu. I-Chemical Mechanical Polishing (CMP) isetshenziselwa ukuthuthukisa ukufana komphezulu.

Ukuqapha Ngesikhathi Sangempela: Ubuchwepheshe bokuhlola ku-inthanethi buqalwa ukuqapha ukujiya kwendawo ngesikhathi sangempela.

Ukusikwa Nge-Laser: Le ndlela inciphisa ukulahleka kwe-kerf futhi ifinyeza imijikelezo yokucubungula, yize indawo ethintekile ekushiseni isalokhu iyinselele.

Ubuchwepheshe Bokucubungula Okuhlanganisiwe: Ukuhlanganisa izindlela zemishini nezamakhemikhali kuthuthukisa ukusebenza kahle kokucubungula.

Lobu buchwepheshe sebuvele bufinyelele ukusetshenziswa kwezimboni. I-Infineon, isibonelo, ithole i-SILTECTRA futhi manje inama-patent ayisisekelo asekela ukukhiqizwa ngobuningi kwama-wafer angu-8 intshi. E-China, izinkampani ezifana ne-Delong Laser zifinyelele ukusebenza kahle kokukhipha kwama-wafer angu-30 nge-ingot ngayinye yokucubungula i-wafer engu-6 intshi, okumele intuthuko engu-40% kunezindlela zendabuko.

Njengoba ukukhiqizwa kwemishini yasekhaya kushesha, lobu buchwepheshe kulindeleke ukuthi bube yisisombululo esiyinhloko sokucutshungulwa kwe-SiC substrate. Njengoba ububanzi bezinto ze-semiconductor bukhula, izindlela zokusika zendabuko seziphelelwe yisikhathi. Phakathi kwezinketho zamanje, ubuchwepheshe besaha lensimbi yedayimane eliphindaphindayo bubonisa amathuba okusebenza athembisayo kakhulu. Ukusika nge-laser, njengendlela entsha, kunikeza izinzuzo ezibalulekile futhi kulindeleke ukuthi kube yindlela yokusika eyinhloko esikhathini esizayo.

2,Ukugaya Ngekristalu Elilodwa le-SiC

Njengommeleli wama-semiconductor esizukulwane sesithathu, i-silicon carbide (i-SiC) inikeza izinzuzo ezibalulekile ngenxa ye-bandgap yayo ebanzi, insimu kagesi eqhekeka kakhulu, ijubane eliphezulu lokukhukhuleka kwama-electron, kanye nokuqhuba kahle kokushisa. Lezi zakhiwo zenza i-SiC ibe yinzuzo ikakhulukazi ekusetshenzisweni kwe-voltage ephezulu (isb., izindawo ezingu-1200V). Ubuchwepheshe bokucubungula ama-substrate e-SiC buyingxenye eyisisekelo yokwenziwa kwedivayisi. Ikhwalithi yobuso kanye nokunemba kwe-substrate kuthinta ngqo ikhwalithi yesendlalelo se-epitaxial kanye nokusebenza kwedivayisi yokugcina.

Inhloso eyinhloko yenqubo yokugaya ukususa amamaki esaha lobuso kanye nezendlalelo zomonakalo ezibangelwa ngesikhathi sokusika, kanye nokulungisa ukuguquka okubangelwa inqubo yokusika. Njengoba i-SiC ilukhuni kakhulu, ukugaya kudinga ukusetshenziswa kwezinto ezisusayo eziqinile njenge-boron carbide noma idayimane. Ukugaya okuvamile kuvame ukuhlukaniswa ngokugaya okuqinile kanye nokugaya okuncane.

2.1 Ukugaya Okuqinile Nokucolekile

Ukugaya kungahlukaniswa ngezigaba ngokusekelwe kusayizi wezinhlayiya ezihudulayo:

Ukugaya Okuqinile: Kusebenzisa izinto ezinkulu ezisusa amamaki esaha kanye nezendlalelo zomonakalo ezibangelwa ngesikhathi sokusika, okuthuthukisa ukusebenza kahle kokucubungula.

Ukugaya Okuncane: Kusebenzisa izinto zokukhuhla ezincane ukususa ungqimba lomonakalo olushiywe ukugaya okuqinile, ukunciphisa ukugoba kobuso, nokuthuthukisa ikhwalithi yobuso.

Abakhiqizi abaningi be-substrate ye-SiC yasekhaya basebenzisa izinqubo zokukhiqiza ezinkulu. Indlela evamile ihilela ukugaya okunezinhlangothi ezimbili kusetshenziswa ipuleti lensimbi elibunjiwe kanye ne-slurry yedayimane e-monocrystalline. Le nqubo isusa ngempumelelo ungqimba lomonakalo olushiywe ukusaha ngocingo, ilungisa ukuma kwe-wafer, futhi yehlisa i-TTV (Total Thickness Variation), i-Bow, kanye ne-Warp. Izinga lokususa izinto lizinzile, ngokuvamile lifinyelela ku-0.8–1.2 μm/min. Kodwa-ke, ubuso be-wafer obuvelayo abunawo umswakama obunobulukhuni obuphezulu—ngokuvamile cishe ku-50 nm—okufaka izidingo eziphakeme ezinyathelweni ezilandelayo zokupholisha.

2.2 Ukugaya Okuhlangothini Olulodwa

Ukugaya ngohlangothi olulodwa kucubungula uhlangothi olulodwa lwe-wafer ngesikhathi. Phakathi nale nqubo, i-wafer ifakwe nge-wax epuletini lensimbi. Ngaphansi kwengcindezi esetshenziswayo, i-substrate ishintshashintsha kancane, bese indawo engaphezulu iba yi-flat. Ngemva kokugaya, indawo engezansi iyalingana. Lapho ingcindezi isusiwe, indawo engaphezulu ivame ukubuyela esimweni sayo sokuqala, okuthinta futhi indawo engezansi kakade - okubangela ukuthi izinhlangothi zombili zigobe futhi zonakale zibe yi-flat.

Ngaphezu kwalokho, ipuleti lokugaya lingagobeka ngesikhathi esifushane, okubangela ukuthi i-wafer ibe yi-convex. Ukuze kugcinwe i-flat ithambile, kudingeka i-dressing njalo. Ngenxa yokusebenza kahle okuphansi kanye ne-wafer ephansi, ukugaya ohlangothini olulodwa akufaneleki ekukhiqizweni ngobuningi.

Ngokuvamile, amasondo okugaya angu-#8000 asetshenziselwa ukugaya kahle. EJapane, le nqubo ivuthiwe futhi isebenzisa ngisho namasondo okupholisha angu-#30000. Lokhu kuvumela ukuthi ubuso bama-wafer acutshunguliwe bube ngaphansi kuka-2 nm, okwenza ama-wafer alungele i-CMP yokugcina (Chemical Mechanical Polishing) ngaphandle kokucutshungulwa okwengeziwe.

2.3 Ubuchwepheshe Bokunciphisa Ohlangothini Olulodwa

Ubuchwepheshe Bokunciphisa I-Diamond Single-Sided buyindlela entsha yokugaya ohlangothini olulodwa. Njengoba kuboniswe kuMfanekiso 5 (akukhonjisiwe lapha), inqubo isebenzisa ipuleti lokugaya eliboshwe ngedayimane. I-wafer iqiniswa nge-vacuum adsorption, kuyilapho i-wafer kanye nesondo lokugaya ledayimane zijikeleza ngasikhathi sinye. Isondo lokugaya liya ngokuya lihla kancane kancane ukuze linciphise i-wafer libe ugqinsi oluqondiwe. Ngemva kokuba uhlangothi olulodwa seluqediwe, i-wafer iyaphendulwa ukuze icutshungulwe olunye uhlangothi.

Ngemva kokunciphisa, i-wafer engu-100 mm ingafeza:

Umnsalo < 5 μm

I-TTV < 2 μm

Ubulukhuni bomphezulu < 1 nm

Le ndlela yokucubungula i-single-wafer inikeza ukuzinza okuphezulu, ukuhambisana okuhle kakhulu, kanye nesilinganiso esiphakeme sokususa izinto. Uma kuqhathaniswa nokugaya okuvamile okunezinhlangothi ezimbili, le ndlela ithuthukisa ukusebenza kahle kokugaya ngaphezu kuka-50%.

2.4 Ukugaya Okunezinhlangothi Ezimbili

Ukugaya okunezinhlangothi ezimbili kusebenzisa ipuleti lokugaya elingaphezulu nelingezansi ukuze kugaywe izinhlangothi zombili ze-substrate ngasikhathi sinye, okuqinisekisa ikhwalithi ephezulu kakhulu ebusweni kuzo zombili izinhlangothi.

Ngesikhathi senqubo, amapuleti okugaya aqala ngokufaka ingcindezi ezindaweni eziphakeme kakhulu zomsebenzi, okubangela ukuguquka nokususwa kwezinto kancane kancane kulawo maphuzu. Njengoba izindawo eziphakeme zilinganisiwe, ingcindezi engaphansi komhlaba iba yinto efanayo kancane kancane, okuholela ekuguqukeni okuqhubekayo kuyo yonke indawo. Lokhu kuvumela ukuthi izindawo eziphezulu nezingezansi zigaywe ngokulinganayo. Uma ukugaya sekuqediwe futhi ingcindezi ikhishwe, ingxenye ngayinye ye-substrate ilulama ngokulinganayo ngenxa yengcindezi efanayo eyayithola. Lokhu kuholela ekugobeni okuncane kanye nokuba yisicaba okuhle.

Ubulukhuni bomphezulu we-wafer ngemva kokugaya buxhomeke kusayizi wezinhlayiya ezihudulayo—izinhlayiya ezincane ziveza izindawo ezibushelelezi. Uma usebenzisa ama-abrasives angu-5 μm ekugayeni okunezinhlangothi ezimbili, ukuthamba kwe-wafer kanye nokwehluka kobukhulu kungalawulwa ngaphakathi kwama-5 μm. Izilinganiso ze-Atomic Force Microscopy (AFM) zibonisa ubulukhuni bomphezulu (Rq) obungaba ngu-100 nm, kanye nemigodi yokugaya efinyelela ku-380 nm ejulile kanye namamaki aqondile abonakalayo abangelwa isenzo sokuhudula.

Indlela ethuthuke kakhulu ihilela ukugaya okunezinhlangothi ezimbili kusetshenziswa ama-polyurethane foam pads ahlanganiswe ne-polycrystalline diamond slurry. Le nqubo ikhiqiza ama-wafer anobulukhuni obuphansi kakhulu, okwenza kube ne-Ra < 3 nm, okuzuzisa kakhulu ekupholishweni okulandelayo kwe-SiC substrates.

Kodwa-ke, ukuklwebha ubuso kuseyinkinga engaxazululwa. Ngaphezu kwalokho, idayimane le-polycrystalline elisetshenziswa kule nqubo likhiqizwa ngokwenziwa kwezinto eziqhumayo, okuyinto enzima ngokobuchwepheshe, ekhiqiza inani eliphansi, futhi ebiza kakhulu.

Ukupholishwa kwamakristalu angewona ama-SiC

Ukuze kufezwe indawo epholishiwe yekhwalithi ephezulu kuma-wafer e-silicon carbide (SiC), ukupholishwa kumele kususe ngokuphelele imigodi yokugaya kanye nama-undulations ebusweni be-nanometer. Umgomo ukukhiqiza indawo ebushelelezi, engenamaphutha engenakho ukungcola noma ukubola, engenamonakalo ongaphansi komhlaba, kanye nokucindezeleka okusele kobuso.

3.1 Ukupholisha Okwenziwa Ngomshini kanye ne-CMP yama-SiC Wafers

Ngemva kokukhula kwe-SiC single crystal ingot, amaphutha ebusweni ayivimbela ukuthi isetshenziswe ngqo ekukhuleni kwe-epitaxial. Ngakho-ke, kudingeka ukucubungula okwengeziwe. I-ingot iqala ngokubunjwa ibe yisimo esijwayelekile se-cylindrical ngokuyijikeleza, bese isikwa ibe ama-wafer kusetshenziswa ukusika ucingo, kulandelwe ukuqinisekiswa kokuqondiswa kwe-crystallographic. Ukupholisha kuyisinyathelo esibalulekile ekuthuthukiseni ikhwalithi ye-wafer, ukubhekana nomonakalo ongaba khona ebusweni obangelwa amaphutha okukhula kwe-crystal kanye nezinyathelo zokucubungula zangaphambilini.

Kunezindlela ezine eziyinhloko zokususa izendlalelo zomonakalo wobuso ku-SiC:

Ukupholisha ngomshini: Kulula kodwa kushiya imihuzuko; kufanelekile ekupholisha kokuqala.

Ukupholisha Kwamakhemikhali (i-CMP): Kususa imihuzuko ngokuchoboza ngamakhemikhali; kufanelekile ukupholisha ngokunembile.

Ukuchoboza i-hydrogen: Kudinga imishini eyinkimbinkimbi, evame ukusetshenziswa ezinqubweni ze-HTCVD.

Ukupholisha okusiza nge-plasma: Kuyinkimbinkimbi futhi akuvamile ukusetshenziswa.

Ukupholisha okwenziwa ngomshini kuphela kuvame ukubangela imihuzuko, kuyilapho ukupholisha okwenziwa ngamakhemikhali kuphela kungaholela ekuqhekekeni okungalingani. I-CMP ihlanganisa zombili izinzuzo futhi inikeza ikhambi eliphumelelayo nelingabizi kakhulu.

Isimiso Sokusebenza se-CMP

I-CMP isebenza ngokujikeleza i-wafer ngaphansi kwengcindezi ebekwe ngokumelene nephedi yokupholisha ejikelezayo. Lokhu kunyakaza okuhlobene, kuhlanganiswe nokuhuzuka komshini okuvela kuma-abrasives amancane ku-slurry kanye nesenzo samakhemikhali sama-reactive agents, kufeza ukuhleleka kwendawo.

Izinto ezibalulekile ezisetshenzisiwe:

Udaka lokupholisha: Liqukethe izinto zokubhula kanye nezinto zokuvuselela amakhemikhali.

Iphedi yokupholisha: Iyaguga ngesikhathi sokusetshenziswa, kunciphisa usayizi wembobo kanye nokusebenza kahle kokulethwa kwe-slurry. Ukugqoka njalo, ngokuvamile kusetshenziswa i-diamond dresser, kuyadingeka ukuze kubuyiselwe ubulukhuni.

Inqubo Ejwayelekile Ye-CMP

Okukhukhumezayo: 0.5 μm idayimane eliludaka

Ubulukhuni bomphezulu oqondiwe: ~0.7 nm

Ukupholisha Kwemishini Yamakhemikhali:

Imishini yokupholisha: I-AP-810 ipholisha ohlangothini olulodwa

Ingcindezi: 200 g/cm²

Isivinini sepuleti: 50 rpm

Isivinini sokubamba se-ceramic: 38 rpm

Ukwakheka kwe-slurry:

I-SiO₂ (30 wt%, i-pH = 10.15)

0–70 wt% H₂O₂ (30 wt%, izinga le-reagent)

Lungisa i-pH ibe ngu-8.5 usebenzisa i-5 wt% KOH kanye ne-1 wt% HNO₃

Izinga lokugeleza kwe-slurry: 3 L/min, lijikeleziswa kabusha

Le nqubo ithuthukisa ngempumelelo ikhwalithi ye-SiC wafer futhi ihlangabezana nezidingo zezinqubo ezingezansi.

Izinselele Zobuchwepheshe Ekupholisheni Kwemishini

I-SiC, njenge-semiconductor ebanzi ye-bandgap, idlala indima ebalulekile embonini ye-elekthronikhi. Njengoba inezakhiwo ezinhle kakhulu zomzimba nezamakhemikhali, amakristalu e-SiC afanelekela izindawo ezibucayi, njengokushisa okuphezulu, imvamisa ephezulu, amandla aphezulu, kanye nokumelana nemisebe. Kodwa-ke, ukuqina kwayo nokubuthakathaka kwayo kuletha izinselele ezinkulu zokugaya nokupholisha.

Njengabakhiqizi abaphambili emhlabeni wonke abashintsha kusuka kuma-wafer angamasentimitha angu-6 kuya kwangu-8, izinkinga ezifana nokuqhekeka kanye nomonakalo we-wafer ngesikhathi sokucubungula sezivele kakhulu, zithinta kakhulu isivuno. Ukubhekana nezinselele zobuchwepheshe zama-substrate e-SiC angamasentimitha angu-8 manje sekuyisilinganiso esibalulekile sokuthuthuka komkhakha.

Esikhathini samasentimitha angu-8, ukucubungula i-SiC wafer kubhekene nezinselele eziningi:

Ukukala i-wafer kuyadingeka ukuze kwandiswe umkhiqizo we-chip ngebhetshi ngayinye, kuncishiswe ukulahlekelwa yi-edge, futhi kuncishiswe izindleko zokukhiqiza—ikakhulukazi uma kubhekwa ukwanda kwesidingo sezinhlelo zokusebenza zezimoto zikagesi.

Nakuba ukukhula kwamakristalu angama-SiC angama-intshi angu-8 sekuvuthiwe, izinqubo zangemuva ezifana nokugaya nokupholisha zisabhekene nezingqinamba, okuholela ekuvuneni okuphansi (40-50%) kuphela.

Ama-wafer amakhulu abhekana nokusatshalaliswa kwengcindezi okuyinkimbinkimbi kakhulu, okwandisa ubunzima bokuphatha ukucindezeleka kokupholisha kanye nokuqina kwesivuno.

Nakuba ubukhulu bama-wafer angu-8 intshi busondela kobama-wafer angu-6 intshi, avame ukulimala kakhulu ngesikhathi sokuphathwa ngenxa yokucindezeleka nokugoba.

Ukuze kuncishiswe ukucindezeleka okuhlobene nokusika, ukugoba, kanye nokuqhekeka, ukusika nge-laser kusetshenziswa kakhulu. Kodwa-ke:

Ama-laser anobude obude abangela umonakalo wokushisa.

Ama-laser amafushane akhiqiza imfucumfucu esindayo futhi ajulise ungqimba lomonakalo, okwandisa ubunzima bokupholisha.

Ukuhamba Komsebenzi Wokupholisha Kwemishini we-SiC

Ukugeleza kwenqubo evamile kuhlanganisa:

Ukusikwa kokuqondisa

Ukugaya okuqinile

Ukugaya kahle

Ukupholisha ngomshini

Ukupholisha Kwemishini Yamakhemikhali (i-CMP) njengesinyathelo sokugcina

Ukukhetha indlela ye-CMP, ukwakheka komzila wenqubo, kanye nokwenza ngcono amapharamitha kubalulekile. Ekukhiqizweni kwe-semiconductor, i-CMP iyisinyathelo esinqumayo sokukhiqiza ama-wafer e-SiC anezindawo ezibushelelezi kakhulu, ezingenamaphutha, futhi ezingenamonakalo, ezibalulekile ekukhuleni kwe-epitaxial yekhwalithi ephezulu.

(a) Susa i-SiC ingot esitsheni sokubethela;

(b) Yenza ukubumba kokuqala usebenzisa ukugaya ububanzi bangaphandle;

(c) Nquma ukuqondiswa kwekristalu usebenzisa amaflethi noma ama-notches okuqondanisa;

(d) Sika i-ingot ibe ama-wafer amancane usebenzisa ukusaha ngezintambo eziningi;

(e) Finyelela ukushelela kobuso okufana nesibuko ngezinyathelo zokugaya nokupholisha.

Ngemva kokuqeda uchungechunge lwezinyathelo zokucubungula, unqenqema lwangaphandle lwe-SiC wafer luvame ukuba lubukhali, okwandisa ingozi yokuqhekeka ngesikhathi sokuphatha noma ukusebenzisa. Ukuze kugwenywe ubuthakathaka obunjalo, kudingeka ukugaya unqenqema.

Ngaphezu kwezinqubo zokusika zendabuko, indlela entsha yokulungiselela ama-wafer e-SiC ihilela ubuchwepheshe bokubopha. Le ndlela ivumela ukwenziwa kwe-wafer ngokubopha ungqimba oluncane lwe-SiC olulodwa-crystal ku-substrate engafani (i-substrate esekelayo).

Isithombe 3 sibonisa ukugeleza kwenqubo:

Okokuqala, ungqimba lwe-delamination lwakhiwa ekujuleni okucacisiwe ebusweni bekristalu elilodwa le-SiC ngokusebenzisa ukufakwa kwe-hydrogen ion noma amasu afanayo. Ikristalu elilodwa le-SiC elicutshunguliwe libe selihlanganiswa nesisekelo esiyisicaba esisekelayo bese licindezelwa futhi lishiswe. Lokhu kuvumela ukudluliselwa nokuhlukaniswa ngempumelelo kwesendlalelo sekristalu elilodwa le-SiC esisekelweni esisekelayo.

Isendlalelo se-SiC esihlukanisiwe sidlula ekuphathweni kwendawo ukuze kufezwe ukuthamba okudingekayo futhi singasetshenziswa kabusha ezinqubweni ezilandelayo zokubopha. Uma kuqhathaniswa nokusikwa kwendabuko kwamakristalu e-SiC, le ndlela inciphisa isidingo sezinto ezibizayo. Nakuba kusenezinselele zobuchwepheshe, ucwaningo nentuthuko kuyaqhubeka ngenkuthalo ukuze kuvunyelwe ukukhiqizwa kwe-wafer engabizi kakhulu.

Njengoba i-SiC inobulukhuni obukhulu kanye nokuzinza kwamakhemikhali—okwenza imelane nokusabela ekushiseni kwegumbi—ukupholisha ngomshini kuyadingeka ukuze kususwe imigodi yokugaya emincane, kuncishiswe umonakalo womphezulu, kususwe imihuzuko, imigodi, kanye namaphutha esikhumba se-orange, kuncishiswe ukugoba komphezulu, kuthuthukiswe ukuthamba, futhi kuthuthukiswe ikhwalithi yomphezulu.

Ukuze uthole indawo ecwebezelisiwe yekhwalithi ephezulu, kuyadingeka:

Lungisa izinhlobo zokuklwebheka,

Nciphisa usayizi wezinhlayiya,

Lungiselela amapharamitha enqubo,

Khetha izinto zokupholisha nama-pad anobulukhuni obanele.

Isithombe 7 sibonisa ukuthi ukupholisha okunezinhlangothi ezimbili nge-abrasives engu-1 μm kungalawula ukuthamba kanye nokwehluka kobukhulu ngaphakathi kwe-10 μm, futhi kunciphise ukugoba kobuso kube cishe yi-0.25 nm.

3.2 Ukupholisha Kwemishini Yamakhemikhali (i-CMP)

I-Chemical Mechanical Polishing (CMP) ihlanganisa ukuguguleka kwezinhlayiya ezincane kakhulu nokugqwala kwamakhemikhali ukuze kwakhiwe ubuso obubushelelezi, obuhlelekile ezintweni ezicutshungulwayo. Isimiso esiyisisekelo yilesi:

Kwenzeka ukusabela kwamakhemikhali phakathi kodaka olupholishayo kanye nobuso be-wafer, kwakha ungqimba oluthambile.

Ukungqubuzana phakathi kwezinhlayiya ezihuzukayo kanye nongqimba oluthambile kususa izinto.

Izinzuzo ze-CMP:

Inqoba izinkinga zokupholisha ngomshini noma ngamakhemikhali kuphela,

Ifinyelela kokubili ukuhlela komhlaba wonke kanye nokwasendaweni,

Ikhiqiza izindawo ezithambile kakhulu futhi ezilukhuni,

Akushiyi monakalo womphezulu noma womphezulu ongaphansi komhlaba.

Ngokuningiliziwe:

I-wafer iyahamba uma iqhathaniswa nephedi yokupholisha ngaphansi kwengcindezi.

Ama-abrasives esikalini se-nanometer (isb., i-SiO₂) ku-slurry ahlanganyela ekugundeni, ekwenzeni buthaka izibopho ze-Si-C covalent kanye nokuthuthukisa ukususwa kwezinto.

Izinhlobo Zezindlela Ze-CMP:

Ukupholisha Okungahlukumezi Kwamahhala: Ama-Abrasives (isb., i-SiO₂) alenga ku-slurry. Ukususwa kwezinto kwenzeka ngokuhuzuka kwemizimba emithathu (i-wafer-pad-abrasive). Usayizi we-Abrasive (ngokuvamile u-60-200 nm), i-pH, kanye nokushisa kumele kulawulwe ngokunembile ukuze kuthuthukiswe ukufana.

Ukupholisha Okuqinile Okungaguquki: Ama-abrasives afakwa ephepheni lokupholisha ukuze kuvinjelwe ukuhlangana—kufanelekile ekucutshungulweni okunembe kakhulu.

Ukuhlanza Ngemva Kokupholisha:

Ama-wafers acwebezelayo adlula:

Ukuhlanza ngamakhemikhali (kufaka phakathi amanzi e-DI kanye nokususwa kwezinsalela ze-slurry),

Ukuhlanza ngamanzi e-DI, kanye

Ukomisa i-nitrogen eshisayo

ukunciphisa ukungcola okungaphezulu.

Ikhwalithi Yomphezulu Nokusebenza

Ubulukhuni bomphezulu bungancishiswa bube yi-Ra < 0.3 nm, kuhlangatshezwane nezidingo ze-semiconductor epitaxy.

Ukuhlela Komhlaba Wonke: Inhlanganisela yokuthambisa ngamakhemikhali kanye nokususwa ngomshini kunciphisa imihuzuko kanye nokugqwala okungalingani, okwenza kube ngcono kakhulu kunezindlela ezihlanzekile zomshini noma ngamakhemikhali.

Ukusebenza Kahle Okuphezulu: Kufanelekela izinto eziqinile neziphuka kalula njenge-SiC, ngamazinga okususa izinto angaphezu kuka-200 nm/h.

Amanye Amasu Okupholisha Avelayo

Ngaphezu kwe-CMP, kunezinye izindlela eziphakanyisiwe, okuhlanganisa:

Ukupholisha nge-electrochemical, ukupholisha noma ukuchoma okusizwa yi-Catalyst, kanye

Ukupholisha kwe-tribochemical.

Kodwa-ke, lezi zindlela zisesesigabeni sokucwaninga futhi ziye zathuthuka kancane kancane ngenxa yezakhiwo zezinto ezibonakalayo ze-SiC eziyinselele.

Ekugcineni, ukucubungula i-SiC kuyinqubo eqhubekayo yokunciphisa ukugoba kanye nokungalingani ukuze kuthuthukiswe ikhwalithi yomphezulu, lapho ukulawulwa kokugoba kanye nokungalingani kubalulekile kuzo zonke izigaba.

Ubuchwepheshe Bokucubungula

Ngesikhathi sesigaba sokugaya i-wafer, i-slurry yedayimane enobukhulu obuhlukene bezinhlayiya isetshenziswa ukugaya i-wafer ibe yi-flat kanye ne-surface rough edingekayo. Lokhu kulandelwa ukupholisha, kusetshenziswa amasu omshini wokupholisha we-mechanical kanye nowe-chemical mechanical (CMP) ukukhiqiza ama-wafer e-silicon carbide (SiC) angenamonakalo.

Ngemva kokupholisha, ama-wafer e-SiC ahlolwa ngekhwalithi eqinile kusetshenziswa amathuluzi anjenge-optical microscopes kanye nama-X-ray diffractometers ukuqinisekisa ukuthi zonke izilinganiso zobuchwepheshe ziyahlangabezana nezindinganiso ezidingekayo. Okokugcina, ama-wafer apholisha ahlanzwa kusetshenziswa izinto zokuhlanza ezikhethekile kanye namanzi ahlanzekile kakhulu ukuze kususwe ukungcola okungaphezulu. Bese omiswa kusetshenziswa igesi ye-nitrogen ehlanzekile kakhulu kanye ne-spin dryers, kuqedwa yonke inqubo yokukhiqiza.

Ngemva kweminyaka eminingi yomzamo, kwenziwe intuthuko enkulu ekucutshungulweni kwekristalu elilodwa le-SiC eShayina. Ekhaya, amakristalu angama-100 mm afakwe i-semi-insulating angama-4H-SiC athuthukiswe ngempumelelo, kanti amakristalu angama-n-type 4H-SiC kanye namakristalu angama-6H-SiC angakhiqizwa ngamaqoqo. Izinkampani ezifana neTankeBlue kanye ne-TYST sezivele zakha amakristalu angama-150 mm SiC angawodwa.

Ngokuphathelene nobuchwepheshe bokucubungula i-wafer ye-SiC, izikhungo zasekhaya ziye zahlola izimo zenqubo kanye nemizila yokusika, ukugaya, kanye nokupholisha ikristalu. Ziyakwazi ukukhiqiza amasampula ahlangabezana nezidingo zokwenziwa kwedivayisi. Kodwa-ke, uma kuqhathaniswa nezindinganiso zomhlaba wonke, ikhwalithi yokucubungula ubuso be-wafer yasekhaya isasele emuva kakhulu. Kunezinkinga eziningana:

Imibono ye-SiC yamazwe ngamazwe kanye nobuchwepheshe bokucubungula buvikelwe kakhulu futhi abufinyeleleki kalula.

Kukhona ukuntuleka kocwaningo lwethiyori kanye nokusekelwa kokuthuthukiswa kwenqubo kanye nokwenza ngcono.

Izindleko zokungenisa imishini nezingxenye zakwamanye amazwe ziphezulu.

Ucwaningo lwasekhaya mayelana nokuklama imishini, ukunemba kokucubungula, kanye nezinto zokwakha lusabonisa izikhala ezinkulu uma kuqhathaniswa namazinga omhlaba.

Njengamanje, amathuluzi amaningi anembile kakhulu asetshenziswa eShayina angeniswa kwamanye amazwe. Imishini yokuhlola kanye nezindlela nakho kudinga ukuthuthukiswa okwengeziwe.

Ngokuqhubeka nokuthuthukiswa kwama-semiconductor esizukulwane sesithathu, ububanzi be-SiC single crystal substrates bukhula kancane kancane, kanye nezidingo eziphakeme zekhwalithi yokucubungula ubuso. Ubuchwepheshe bokucubungula i-wafer bube ngesinye sezinyathelo eziyinselele kakhulu kwezobuchwepheshe ngemuva kokukhula kwe-SiC single crystal.

Ukuze kuxazululwe izinselele ezikhona ekucubungulweni, kubalulekile ukuqhubeka nokufunda izindlela ezihilelekile ekusikeni, ekugayeni nasekupholisheni, kanye nokuhlola izindlela zenqubo ezifanele kanye nemizila yokukhiqizwa kwe-SiC wafer. Ngesikhathi esifanayo, kubalulekile ukufunda kubuchwepheshe obuthuthukisiwe bokucubungula bamazwe ngamazwe futhi usebenzise amasu okusebenza ngokunemba okuphezulu kanye nemishini yokukhiqiza ukuze kukhiqizwe ama-substrate asezingeni eliphezulu.

Njengoba usayizi we-wafer ukhula, ubunzima bokukhula kwekristalu kanye nokucubungula nakho buyakhula. Kodwa-ke, ukusebenza kahle kokukhiqiza kwamadivayisi angezansi kuthuthuka kakhulu, futhi izindleko zeyunithi ziyancishiswa. Njengamanje, abahlinzeki be-wafer abakhulu be-SiC emhlabeni jikelele banikeza imikhiqizo esukela kumasentimitha angu-4 kuya kwangu-6 ububanzi. Izinkampani ezihamba phambili njengeCree kanye ne-II-VI seziqalile ukuhlela ukuthuthukiswa kwemigqa yokukhiqiza i-wafer ye-SiC engamasentimitha angu-8.