Imeko yangoku kunye neendlela zobuchwepheshe bokucubungula i-SiC Wafer

Njengesixhobo se-semiconductor substrate sesizukulwana sesithathu,i-silicon carbide (i-SiC)I-single crystal inamathuba amaninzi okusetyenziswa ekuveliseni izixhobo ze-elektroniki ezinamandla aphezulu kunye namandla aphezulu. Itekhnoloji yokucubungula ye-SiC idlala indima ebalulekileyo ekuveliseni izixhobo ze-substrate ezikumgangatho ophezulu. Eli nqaku lizisa imeko yangoku yophando malunga netekhnoloji yokucubungula i-SiC eTshayina nakwamanye amazwe, lihlalutya kwaye lithelekisa iindlela zokusika, ukugaya, kunye nokupolisha, kunye neendlela zokusila, ukugungqa kwe-wafer kunye noburhabaxa bomphezulu. Likwabonisa imingeni ekhoyo ekucubungulweni kwe-wafer ye-SiC kwaye lixoxa ngezikhokelo zophuhliso lwexesha elizayo.

I-silicon carbide (i-SiC)Iiwafers zizinto ezibalulekileyo ezisisiseko kwizixhobo ze-semiconductor zesizukulwana sesithathu kwaye zibaluleke kakhulu kwaye zinamandla emarike kwimimandla efana ne-microelectronics, i-power electronics, kunye nezibane ze-semiconductor. Ngenxa yobunzima obuphezulu kakhulu kunye nokuzinza kweekhemikhaliIikristale ezingatshatanga zeSiC, iindlela zemveli zokucubungula ii-semiconductor azifanelekanga ngokupheleleyo kwimishini yazo. Nangona iinkampani ezininzi zamazwe ngamazwe zenze uphando olubanzi malunga nokucubungula okuyimfuneko kwe-SiC single crystals, ubuchwepheshe obufanelekileyo bugcinwa buyimfihlo kakhulu.

Kwiminyaka yakutshanje, iTshayina inyuse imizamo ekuphuhlisweni kwezinto zekristale enye yeSiC kunye nezixhobo. Nangona kunjalo, ukuqhubela phambili kwetekhnoloji yesixhobo seSiC kweli lizwe ngoku kuthintelwe yimida kwitekhnoloji yokucubungula kunye nomgangatho we-wafer. Ke ngoko, kubalulekile ukuba iTshayina iphucule amandla okucubungula iSiC ukuze kuphuculwe umgangatho we-substrates zekristale enye yeSiC kwaye kufezekiswe ukusetyenziswa kwayo okusebenzayo kunye nemveliso eninzi.

Amanyathelo aphambili okucubungula aquka: ukusika → ukugaya okurhabaxa → ukugaya okucolekileyo → ukupolisha okurhabaxa (ukupolisha ngoomatshini) → ukupolisha okucolekileyo (ukupolisha ngoomatshini beekhemikhali, i-CMP) → ukuhlolwa.

Ukusikwa kweekristale zeSiC eziSinye

Ekuqhutyweni kweIikristale ezingatshatanga zeSiC, ukusika linyathelo lokuqala nelibaluleke kakhulu. I-wafer's bow, i-warp, kunye ne-total thickness variation (TTV) ezivela kwinkqubo yokusika zimisela umgangatho kunye nokusebenza kakuhle kwemisebenzi yokugaya nokupolisha elandelayo.

Izixhobo zokusika zingahlulwa ngokwemilo zibe ziisarha zedayimani yangaphakathi (ID), iisarha zedayimani zangaphandle (OD), iisarha zebhendi, kunye neesarha zentambo. Iisarha zentambo, zona, zinokuhlulwa ngohlobo lwazo lokuhamba zibe ziinkqubo zentambo ezijikelezayo nezijikelezayo (ezingenasiphelo). Ngokusekelwe kwindlela yokusika ye-abrasive, iindlela zokusika i-wire saw zinokwahlulwa zibe ziintlobo ezimbini: ukusarha intambo erhabaxa yasimahla kunye nokusarha intambo yedayimani erhabaxa esisigxina.

1.1 Iindlela Zokusika Zemveli

Ubunzulu bokusika kweesarha zedayamitha zangaphandle (OD) bunqunyelwe bububanzi beblade. Ngexesha lenkqubo yokusika, iblade idla ngokungcangcazela nokuphambuka, nto leyo ebangela amazinga aphezulu engxolo kunye nokuqina okungekuhle. Iisarha zedayamitha zangaphakathi (ID) zisebenzisa ii-diamond abrasives kumjikelezo wangaphakathi weblade njengomphetho wokusika. Ezi blade zinokuba ncinci njenge-0.2 mm. Ngexesha lokusika, i-ID blade ijikeleza ngesantya esiphezulu ngelixa izinto eziza kunqunyulwa zihamba ngokujikelezayo ngokumalunga nombindi weblade, ziphumelela ekunqumleni ngale ntshukumo ihambelanayo.

Iisarha zebhandi yedayimani zifuna ukumisa rhoqo kunye nokubuyela umva, kwaye isantya sokusika siphantsi kakhulu—ngesiqhelo asidluli kwi-2 m/s. Zikwanengxaki yokuguguleka okukhulu koomatshini kunye neendleko eziphezulu zokulungisa. Ngenxa yobubanzi beblade yesarha, irediyasi yokusika ayinakuba ncinci kakhulu, kwaye ukusika izilayi ezininzi akunakwenzeka. Ezi zixhobo zemveli zokusarha zithintelwe bubulukhuni besiseko kwaye azinakwenza ukusika okugobileyo okanye zinemitha yokujika ekhawulezileyo. Ziyakwazi ukusika ngokuthe tye kuphela, zivelise ii-kerfs ezibanzi, zinezinga eliphantsi lesivuno, kwaye ke ngoko azifanelekanga ukusika.Iikristale zeSiC.

1.2 Ukusika iintambo ezininzi ezirhabaxa zasimahla

Indlela yokusika i-free abrasive wire saw isebenzisa intshukumo ekhawulezileyo yentambo ukuze ithwale udaka iye kwi-kerf, nto leyo evumela ukuba izinto zisuswe. Ngokuyintloko isebenzisa isakhiwo esiphinda-phindayo kwaye okwangoku yindlela evuthiweyo nesetyenziswa kakhulu yokusika i-silicon ye-single-crystal ene-wafer eninzi. Nangona kunjalo, ukusetyenziswa kwayo ekusikeni i-SiC akukafundwa kakhulu.

Iisarha zentsimbi ezirhabaxa zasimahla zinokucubungula ii-wafer ezinobukhulu obungaphantsi kwe-300 μm. Zinika ilahleko ephantsi ye-kerf, azifane zibangele ukuqhekeka, kwaye zikhokelela kumgangatho olungileyo womphezulu. Nangona kunjalo, ngenxa yendlela yokususa izinto—esekelwe ekuqengqelekeni nasekuvalekeni kwee-abrasives—umphezulu we-wafer udla ngokuphuhla uxinzelelo olukhulu olushiyekileyo, ii-microcracks, kunye neeleya zomonakalo onzulu. Oku kukhokelela ekugobeni kwe-wafer, kwenza kube nzima ukulawula ukuchaneka kweprofayili yomphezulu, kwaye kwandisa umthwalo kumanyathelo okucubungula alandelayo.

Ukusebenza kokusika kuchaphazeleka kakhulu yi-slurry; kuyimfuneko ukugcina ubukhali be-abrasives kunye noxinzelelo lwe-slurry. Unyango lwe-slurry kunye nokurisayikilisha kuyabiza. Xa kusikwa ii-ingots ezinkulu, ii-abrasives zinobunzima bokungena kwii-kerfs ezinzulu nezinde. Phantsi kobukhulu obufanayo be-abrasive grain, ilahleko ye-kerf inkulu kuneyee-fixed-abrasive wire saws.

1.3 I-Fixed Abrasive Diamond Wire Saw Multi-Wire Cutting

Iisarha zentsimbi yedayimani ezirhabaxa ezilungisiweyo zihlala zenziwa ngokufaka amasuntswana edayimani kwi-substrate yentsimbi ngokusebenzisa iindlela zokubopha nge-electroplating, sintering, okanye resin. Iisarha zentsimbi yedayimani ezifakwe nge-electroplated zibonelela ngeenzuzo ezifana nee-kerfs ezincinci, umgangatho ongcono wesilayi, ukusebenza kakuhle, ungcoliseko oluphantsi, kunye nokukwazi ukusika izinto ezinobunzima obuphezulu.

Isarha yentsimbi yedayimani ephinda-phindanayo yeyona ndlela isetyenziswa kakhulu yokusika iSiC. Umfanekiso 1 (awuboniswanga apha) ubonisa ukuba umphezulu we-wafers zeSiC ezisikiweyo usebenzisa le ndlela. Njengoko ukusika kuqhubeka, i-wafer warpage iyanda. Oku kungenxa yokuba indawo yoqhagamshelwano phakathi kwentambo nezinto ezisetyenzisiweyo iyanda njengoko intambo isiya ezantsi, nto leyo enyusa ukumelana nokungcangcazela kwentambo. Xa intambo ifikelela kububanzi obuphezulu be-wafer, ukungcangcazela kufikelele kwincopho yayo, nto leyo ebangela i-warpage ephezulu.

Kwizigaba zokugqibela zokusikwa, ngenxa yokuba ucingo lukhawuleziswa, luhamba ngesantya esizinzileyo, lucotha, luyeka, kwaye lubuyela umva, kunye nobunzima bokususa inkunkuma ngesixhobo sokupholisa, umgangatho womphezulu we-wafer uyawohloka. Ukuguqulwa kwentambo kunye nokuguquguquka kwesantya, kunye namasuntswana amakhulu edayimani kwintambo, zezona zinto ziphambili zokukrweleka komphezulu.

1.4 Iteknoloji Yokwahlulwa Okubandayo

Ukwahlulwa kwekristale enye yeSiC ngokubandayo yinkqubo entsha kwicandelo lokucubungula izinto ze-semiconductor zesizukulwana sesithathu. Kwiminyaka yakutshanje, itsale ingqalelo enkulu ngenxa yeenzuzo zayo eziphawulekayo ekuphuculeni isivuno kunye nokunciphisa ukulahleka kwezinto. Le teknoloji ingahlalutywa kwiinkalo ezintathu: umgaqo wokusebenza, ukuhamba kwenkqubo, kunye neenzuzo eziphambili.

Ukumiselwa koBume beCristal kunye nokuGriwa koBude obuNgaphandle: Ngaphambi kokuba kusetyenzwe, kufuneka kumiselwe ubume beCristal ye-SiC ingot. Emva koko i-ingot ibunjwa ibe yisakhiwo esisilinda (esibizwa ngokuba yi-SiC puck) ngokugrinda ngobubanzi obungaphandle. Eli nyathelo libeka isiseko sokusika nokusika okulandelayo.

Ukusikwa kweeNtambo ezininzi: Le ndlela isebenzisa amasuntswana arhabaxa adityaniswe neentambo zokusika ukusika i-ingot esilinda. Nangona kunjalo, inengxaki yokulahleka okukhulu kwe-kerf kunye neengxaki zokungalingani komphezulu.

Iteknoloji Yokusika NgeLaser: Ilaser isetyenziselwa ukwenza umaleko oguquliweyo ngaphakathi kwikristale, apho izilayi ezincinci zinokususwa khona. Le ndlela inciphisa ukulahleka kwezinto kwaye iphucula ukusebenza kakuhle kokucubungula, okwenza kube yindlela entsha ethembisayo yokusika i-wafer yeSiC.

Ukulungiswa kweNkqubo yokusika

Ukusikwa kwe-Abrasive Multi-Wire okuQinisekisiweyo: Le yiteknoloji eqhelekileyo okwangoku, efanelekileyo kwiimpawu zobunzima obuphezulu be-SiC.

Umatshini wokukhupha umbane (i-EDM) kunye neTekhnoloji yoKwahlula uBumdaka: Ezi ndlela zibonelela ngezisombululo ezahlukeneyo ezenzelwe iimfuno ezithile.

Inkqubo yokuPolisha: Kubalulekile ukulinganisela izinga lokususwa kwezinto kunye nomonakalo womphezulu. I-Chemical Mechanical Polishing (CMP) isetyenziselwa ukuphucula ukufana komphezulu.

Ukubeka iliso ngexesha langempela: Iiteknoloji zokuhlola kwi-intanethi ziqaliswa ukujonga uburhabaxa bomphezulu ngexesha langempela.

Ukusikwa ngeLaser: Le ndlela inciphisa ukulahleka kwe-kerf kwaye inciphisa imijikelo yokucubungula, nangona indawo echaphazelekileyo kubushushu isengumngeni.

IiTekhnoloji zoLungiselelo lweHybrid: Ukudibanisa iindlela zoomatshini nezekhemikhali kuphucula ukusebenza kakuhle kokucubungula.

Le teknoloji sele ifikelele kwisicelo semizi-mveliso. Umzekelo, i-Infineon ifumene i-SILTECTRA kwaye ngoku ineepatenti eziphambili ezixhasa ukuveliswa ngobuninzi kwee-wafers ze-intshi ezi-8. E-China, iinkampani ezifana ne-Delong Laser zifikelele kwimveliso esebenzayo yee-wafers ezingama-30 nge-ingot nganye yokucubungula ii-wafers ze-intshi ezi-6, nto leyo ebonisa uphuculo lwe-40% kuneendlela zemveli.

Njengoko ukwenziwa kwezixhobo zasekhaya kukhawulezisa, le teknoloji kulindeleke ukuba ibe sisisombululo esiphambili sokucubungula i-SiC substrate. Ngokwanda kobubanzi bezinto ze-semiconductor, iindlela zokusika zendabuko ziye zaphelelwa lixesha. Phakathi kweendlela ezikhoyo ngoku, iteknoloji yesarha yedayimani ephinda-phindayo ibonisa amathuba okusetyenziswa athembisayo. Ukusika nge-laser, njengendlela entsha, kunika iingenelo ezibalulekileyo kwaye kulindeleke ukuba ibe yindlela ephambili yokusika kwixesha elizayo.

2,Ukusila ngeSiC Single Crystal

Njengommeli wee-semiconductors zesizukulwana sesithathu, i-silicon carbide (i-SiC) inika iingenelo ezibalulekileyo ngenxa ye-bandgap yayo ebanzi, intsimi yombane eqhekekileyo kakhulu, isantya esiphezulu sokuntywila kwe-electron, kunye nokuqhuba kakuhle kobushushu. Ezi mpawu zenza i-SiC ibe luncedo ngakumbi kwizicelo ze-voltage ephezulu (umz., iindawo ze-1200V). Itekhnoloji yokucubungula ii-substrates ze-SiC yinxalenye ebalulekileyo yokwenziwa kwesixhobo. Umgangatho womphezulu kunye nokuchaneka kwe-substrate kuchaphazela ngokuthe ngqo umgangatho womaleko we-epitaxial kunye nokusebenza kwesixhobo sokugqibela.

Injongo ephambili yenkqubo yokusila kukususa amabala omphezulu wesarha kunye neengqimba zomonakalo ezibangelwe ngexesha lokusikwa, kunye nokulungisa ukuguquka okubangelwa yinkqubo yokusila. Ngenxa yobunzima obuphezulu kakhulu beSiC, ukusila kufuna ukusetyenziswa kwezinto ezilukhuni ezifana ne-boron carbide okanye idayimani. Ukusila okuqhelekileyo kudla ngokwahlulwahlulwa kube kukusila okurhabaxa kunye nokusila okucolekileyo.

2.1 Ukusila Okurhabaxa Nokucolekileyo

Ukusila kunokwahlulwahlulwa ngokusekelwe kubukhulu beentwana ezirhabaxa:

Ukusila Okurhabaxa: Kusebenzisa izinto ezinkulu ezirhabaxa ngokuyintloko ukususa amabala esarha kunye nomonakalo obangelwe ngexesha lokusika, nto leyo ephucula ukusebenza kakuhle kokusila.

Ukusila Okuncinci: Kusebenzisa izinto ezicothayo ukususa umaleko womonakalo oshiywe kukusila okuqinileyo, ukunciphisa uburhabaxa bomphezulu, kunye nokuphucula umgangatho womphezulu.

Abavelisi abaninzi be-substrate ye-SiC yasekhaya basebenzisa iinkqubo ezinkulu zemveliso. Indlela eqhelekileyo ibandakanya ukugaya okumacala amabini kusetyenziswa ipleyiti yesinyithi esityhidiweyo kunye ne-monocrystalline diamond slurry. Le nkqubo isusa ngempumelelo umaleko womonakalo oshiywe kukusarha ucingo, ilungisa imo ye-wafer, kwaye inciphisa i-TTV (Total Thickness Variation), i-Bow, kunye ne-Warp. Izinga lokususa izinto lizinzile, lidla ngokufikelela kwi-0.8–1.2 μm/min. Nangona kunjalo, umphezulu we-wafer ophumayo awunamatheli kwaye unoburhabaxa obuphezulu—ngesiqhelo malunga ne-50 nm—obangela iimfuno eziphezulu kumanyathelo alandelayo okupholisha.

2.2 Ukusila Okunecala Elinye

Ukusila ngacala linye kusetyenziswa icala elinye kuphela le-wafer ngexesha. Ngeli xesha le nkqubo, i-wafer ifakwe i-wax kwipleyiti yentsimbi. Xa isetyenziswa ngoxinzelelo, i-substrate itshintsha kancinci, kwaye umphezulu ophezulu uyasicaba. Emva kokusila, umphezulu ongezantsi uyalingana. Xa uxinzelelo lususiwe, umphezulu ongaphezulu udla ngokubuyela kwimo yawo yokuqala, nto leyo echaphazela nomphezulu osezantsi osele usemhlabeni—nto leyo ebangela ukuba omabini amacala ajijeke aze awe.

Ngaphezu koko, ipleyiti yokusila inokuba yingqukuva ngexesha elifutshane, nto leyo ebangela ukuba i-wafer ibe yingqukuva. Ukuze ipleyiti ihlale ithambile, kufuneka idityaniswe rhoqo. Ngenxa yokusebenza kancinci kunye nokuba yingqukuva ethambileyo, ukusila ngacala linye akufanelekanga ukuba kwenziwe ngobuninzi.

Ngokwesiqhelo, amavili okugaya angama-#8000 asetyenziselwa ukugaya kakuhle. EJapan, le nkqubo ikhulile kwaye isebenzisa amavili okucoca angama-#30000. Oku kuvumela ukuba uburhabaxa bomphezulu weewafers ezicutshungulweyo bufikelele ngaphantsi kwe-2 nm, nto leyo eyenza iiwafers zilungele i-CMP yokugqibela (iChemical Mechanical Polishing) ngaphandle kokulungiswa okongezelelweyo.

2.3 Ubuchwepheshe bokuThintsa obunecala elinye

Iteknoloji yokuThintsa iDayimane kwicala elinye yindlela entsha yokusila icala elinye. Njengoko kubonisiwe kuMfanekiso 5 (awuboniswanga apha), le nkqubo isebenzisa ipleyiti yokusila enedayimani. I-wafer iqiniswa nge-vacuum adsorption, ngelixa zombini i-wafer kunye nevili lokusila ledayimani zijikeleza ngaxeshanye. Ivili lokusila liyahamba kancinci kancinci ukuze linciphise i-wafer ibe bubukhulu obujoliswe kuyo. Emva kokuba elinye icala ligqityiwe, i-wafer iyajikwa ukuze icutshungulwe kwelinye icala.

Emva kokunciphisa, i-wafer eyi-100 mm inokufezekisa oku kulandelayo:

Ibhombo < 5 μm

I-TTV < 2 μm

Uburhabaxa bomphezulu < 1 nm

Le ndlela yokucubungula i-single-wafer inika uzinzo oluphezulu, ukuhambelana okuhle kakhulu, kunye nesantya esiphezulu sokususa izinto. Xa kuthelekiswa nokugaya okuqhelekileyo okumacala omabini, le ndlela iphucula ukusebenza kakuhle kokugawula ngaphezulu kwe-50%.

2.4 Ukusila Okumacala Amabini

Ukugaya okumacala mabini kusebenzisa ipleyiti yokusila ephezulu nesezantsi ngaxeshanye ukugaya amacala omabini esiseko, ukuqinisekisa umgangatho ophezulu womphezulu kumacala omabini.

Ngexesha lenkqubo, iipleyiti zokusila ziqala ngokufaka uxinzelelo kwiindawo eziphezulu zomsebenzi, nto leyo ebangela ukuguquka nokususwa kwezinto kancinci kancinci kwezo ndawo. Njengoko iindawo eziphakamileyo zilingana, uxinzelelo olukwi-substrate luya lufana kancinci kancinci, nto leyo ebangela ukuguquka okulinganayo kuwo wonke umphezulu. Oku kuvumela ukuba iindawo eziphezulu nezisezantsi zigaywe ngokulinganayo. Nje ukuba ukusila kugqityiwe kwaye uxinzelelo lukhululwe, inxalenye nganye ye-substrate ibuyela kwimeko yayo efanayo ngenxa yoxinzelelo olulinganayo ebelinalo. Oku kukhokelela ekugobeni okuncinci kunye nokuthamba okuhle.

Uburhabaxa bomphezulu we-wafer emva kokugaywa buxhomekeke kubukhulu be-particle erhabaxa—amasuntswana amancinci avelisa iindawo ezithambileyo. Xa usebenzisa ii-abrasives ze-5 μm zokugaywa ngamacala amabini, uburhabaxa be-wafer kunye nokuguquguquka kobukhulu kunokulawulwa ngaphakathi kwe-5 μm. Ukulinganiswa kwe-Atomic Force Microscopy (AFM) kubonisa uburhabaxa bomphezulu (Rq) obumalunga ne-100 nm, kunye nemigodi yokugaywa efikelela kwi-380 nm nzulu kunye namanqaku acacileyo abangelwa yintshukumo erhabaxa.

Indlela ephucukileyo ngakumbi ibandakanya ukugaywa okumacala omabini kusetyenziswa ii-polyurethane foam pads ezidityaniswe ne-polycrystalline diamond slurry. Le nkqubo ivelisa ii-wafers ezinoburhabaxa obuphantsi kakhulu, nto leyo efikelela kwi-Ra < 3 nm, nto leyo eluncedo kakhulu ekupolishweni kwe-SiC substrates kamva.

Nangona kunjalo, ukukrwela umphezulu kusengumba ongasombululwanga. Ukongeza, idayimani ye-polycrystalline esetyenziswa kule nkqubo iveliswa ngokusebenzisa i-explosive synthesis, ekunzima kakhulu kwezobuchwepheshe, ivelisa ubungakanani obuphantsi, kwaye ibiza kakhulu.

Ukupholishwa kweekristale eziSinye zeSiC

Ukuze kufunyanwe umphezulu ocoliweyo osemgangathweni ophezulu kwii-wafers ze-silicon carbide (SiC), ukupolisha kufuneka kususe ngokupheleleyo imingxuma yokugaya kunye nee-undulations zomphezulu we-nanometer. Injongo kukuvelisa umphezulu ogudileyo, ongenaziphene ongenangcoliseko okanye ukubola, ongenamonakalo ongaphantsi komhlaba, kwaye ongenaxinzelelo lomphezulu olushiyekileyo.

3.1 Ukupholisha ngoomatshini kunye ne-CMP yee-SiC Wafers

Emva kokukhula kwe-SiC single crystal ingot, iziphene zomphezulu ziyayithintela ukuba isetyenziswe ngokuthe ngqo ekukhuleni kwe-epitaxial. Ke ngoko, kufuneka ukucubungula okungakumbi. I-ingot iqala ngokuyilwa ibe yimo eqhelekileyo ye-cylindrical ngokuyijikeleza, ize inqunyulwe ibe zii-wafers kusetyenziswa ukusika ucingo, kulandele ukuqinisekiswa kokujonga kwe-crystallographic. Ukupolisha linyathelo elibalulekileyo ekuphuculeni umgangatho we-wafer, ukulungisa umonakalo onokubakho womphezulu obangelwa ziziphene zokukhula kwe-crystal kunye namanyathelo okucubungula kwangaphambili.

Kukho iindlela ezine eziphambili zokususa iileya zomonakalo kumphezulu kwiSiC:

Ukupholisha ngoomatshini: Kulula kodwa kushiya imikrwelo; kufanelekile xa kupholisha okokuqala.

Ukupolishwa Kweekhemikhali (i-CMP): Kususa imikrwelo ngokugrumba iikhemikhali; kufanelekile ukupolishwa ngokuchanekileyo.

Ukugrumba i-hydrogen: Kufuna izixhobo ezintsonkothileyo, ezisetyenziswa rhoqo kwiinkqubo ze-HTCVD.

Ukupholisha okuncediswa yiplasma: Kunzima kwaye akusetyenziswa rhoqo.

Ukupholisha oomatshini kuphela kudla ngokubangela imikrwelo, ngelixa ukupholisha okwenziwa ngamakhemikhali kuphela kunokukhokelela ekugrumbeni okungalinganiyo. I-CMP idibanisa zombini iingenelo kwaye inikezela ngesisombululo esisebenzayo nesingabizi kakhulu.

Umgaqo-nkqubo wokusebenza we-CMP

I-CMP isebenza ngokujikelezisa i-wafer phantsi koxinzelelo olubekiweyo ngokuchasene nephedi yokupolisha ejikelezayo. Olu tshintsho, ludibene nokukrazulwa koomatshini okuvela kwii-abrasives ezinobukhulu obuncinci kwi-slurry kunye nesenzo seekhemikhali see-reactive agents, lufezekisa ukucwangciswa komphezulu.

Izixhobo eziphambili ezisetyenzisiweyo:

Udaka lokupholisha: Luneziqholo kunye neekhemikhali ezisetyenziswa njengezinto ezisusa ukungcola.

Iphedi yokupolisha: Iyaphela xa isetyenziswa, nto leyo enciphisa ubungakanani bemingxuma kunye nokusebenza kakuhle kokuhambisa uthuli. I-dressing eqhelekileyo, edla ngokusetyenziswa kwi-diamond dresser, iyafuneka ukuze kubuyiselwe uburhabaxa.

Inkqubo eqhelekileyo ye-CMP

I-Abrasive: I-0.5 μm yedayimani eludaka

Uburhabaxa bomphezulu ekujoliswe kuwo: ~0.7 nm

Ukupholisha oomatshini beKhemikhali:

Izixhobo zokupolisha: I-AP-810 ipolisha icala elinye

Uxinzelelo: 200 g/cm²

Isantya sepleyiti: 50 rpm

Isantya sokubamba seCeramic: 38 rpm

Ukwakheka kodaka:

I-SiO₂ (30 wt%, i-pH = 10.15)

0–70 wt% H₂O₂ (30 wt%, uhlobo lwe-reagent)

Lungisa i-pH ibe yi-8.5 usebenzisa i-5 wt% KOH kunye ne-1 wt% HNO₃

Izinga lokuhamba kodaka: 3 L/min, lijikeleziswa kwakhona

Le nkqubo iphucula ngokufanelekileyo umgangatho we-SiC wafer kwaye ihlangabezana neemfuno zeenkqubo ezisezantsi.

Imingeni yoBugcisa kwiMechanical Polishing

I-SiC, njenge-semiconductor ebanzi ye-bandgap, idlala indima ebalulekileyo kushishino lwe-elektroniki. Ngeempawu zomzimba nezekhemikhali ezibalaseleyo, iikristale ze-SiC ezizodwa zilungele iindawo ezishushu kakhulu, ezinje ngobushushu obuphezulu, amaza aphezulu, amandla aphezulu, kunye nokumelana nemisebe. Nangona kunjalo, ubume bayo obuqinileyo nobubuthathaka buzisa imingeni emikhulu yokusila nokupolisha.

Njengabavelisi abaphambili kwihlabathi liphela abatshintsha ukusuka kwii-wafers ezi-6-intshi ukuya kwii-8-intshi, imiba efana nokuqhekeka kunye nomonakalo we-wafer ngexesha lokucubungula iye yabonakala ngakumbi, nto leyo echaphazela kakhulu isivuno. Ukujongana nemingeni yobuchwephesha yee-substrates ze-SiC ezi-8-intshi ngoku luphawu oluphambili lokuqhubela phambili kweli shishini.

Kwixesha le-8-intshi, ukucutshungulwa kwe-SiC wafer kujongana nemingeni emininzi:

Ukulinganisa i-wafer kuyimfuneko ukwandisa imveliso ye-chip ngebhetshi nganye, ukunciphisa ilahleko yomphetho, kunye nokunciphisa iindleko zemveliso—ingakumbi xa kujongwa ukunyuka kwemfuno kwizicelo zezithuthi zombane.

Nangona ukukhula kweekristale zeSiC eziziisentimitha ezi-8 kuye kwakhula, iinkqubo zangasemva ezifana nokusila nokupolisha zisajongene nemiqobo, nto leyo ebangela isivuno esiphantsi (ngama-40–50%) kuphela.

Iiwafer ezinkulu zifumana usasazo olunzima ngakumbi loxinzelelo, nto leyo eyonyusa ubunzima bokulawula uxinzelelo lokupholisha kunye nokuhambelana kwemveliso.

Nangona ubukhulu bee-wafers eziziisentimitha ezi-8 busondela kobo be-wafers eziziisentimitha ezi-6, zisengozini enkulu yokonakala xa ziphathwa ngenxa yoxinzelelo kunye nokugoba.

Ukunciphisa uxinzelelo olunxulumene nokusika, ukuqhekeka, kunye nokuqhekeka, ukusika nge-laser kusetyenziswa ngakumbi. Nangona kunjalo:

Iilaser ezinde zibangela umonakalo kubushushu.

Iilaser ezimfutshane zamaza zivelisa inkunkuma enzima kwaye ziyenza ibe nzulu umaleko womonakalo, nto leyo eyandisa ubunzima bokupolisha.

Ukuhamba komsebenzi wokuPolisha oomatshini kwiSiC

Ukuhamba kwenkqubo ngokubanzi kuquka:

Ukusikwa kolwazi

Ukugaya okurhabaxa

Ukusila kakuhle

Ukupholisha ngoomatshini

I-Chemical Mechanical Polishing (CMP) njengenyathelo lokugqibela

Ukukhethwa kwendlela ye-CMP, uyilo lwendlela yenkqubo, kunye nokwenza ngcono iiparameters kubaluleke kakhulu. Kwimveliso ye-semiconductor, i-CMP linyathelo elibalulekileyo lokuvelisa ii-wafers ze-SiC ezineendawo ezigudileyo kakhulu, ezingenasiphako, kwaye ezingenamonakalo, ezibalulekileyo ekukhuleni kwe-epitaxial esemgangathweni ophezulu.

(a) Susa ingot yeSiC kwisikrucible;

(b) Yenza ukubumba kokuqala usebenzisa ukugrinda okungaphezulu kobubanzi;

(c) Chonga indlela i-crystal orientation ehambelana ngayo usebenzisa ii-alignment flats okanye ii-notches;

(d) Sika i-ingot ibe zii-wafers ezibhityileyo usebenzisa i-multi-wire sawing;

(e) Fumana ubuthambile bomphezulu obufana nesipili ngokuwugaya nokuwupholisha.

Emva kokugqiba uthotho lwamanyathelo okucubungula, umphetho wangaphandle we-SiC wafer uhlala ubukhali, nto leyo eyonyusa umngcipheko wokuqhekeka ngexesha lokuphathwa okanye ukusetyenziswa. Ukuze kuthintelwe ubuthathaka obunjalo, kufuneka ukugaywa komphetho.

Ukongeza kwiinkqubo zemveli zokusika, indlela entsha yokulungiselela ii-wafer ze-SiC ibandakanya iteknoloji yokubopha. Le ndlela ivumela ukwenziwa kwee-wafer ngokubopha umaleko omncinci we-SiC one-crystal kwi-substrate eyahlukileyo (i-substrate exhasayo).

Umfanekiso 3 ubonisa ukuhamba kwenkqubo:

Okokuqala, umaleko we-delamination wenziwa kubunzulu obuthile kumphezulu wekristale enye ye-SiC ngokusebenzisa ukufakelwa kwe-hydrogen ion okanye iindlela ezifanayo. Ikristale enye ye-SiC ecutshungulwayo emva koko ibotshelelwa kwi-substrate exhasayo ethe tyaba kwaye iphantsi koxinzelelo kunye nobushushu. Oku kuvumela ukudluliselwa kunye nokwahlulwa ngempumelelo komaleko wekristale enye ye-SiC kwi-substrate exhasayo.

Umaleko weSiC owahlulweyo uphathwa ngaphezulu ukuze kufezekiswe ukuthamba okufunekayo kwaye unokuphinda usetyenziswe kwiinkqubo ezilandelayo zokubopha. Xa kuthelekiswa nokusika iikristale zeSiC ngokwesiko, le ndlela inciphisa imfuno yezinto ezibizayo. Nangona imingeni yobugcisa isekho, uphando nophuhliso luyaqhubeka ngamandla ukuze kuvumeleke ukuveliswa kwe-wafer engabizi kakhulu.

Ngenxa yobunzima obuphezulu kunye nokuzinza kweekhemikhali zeSiC—ezenza ukuba imelane neempendulo kubushushu begumbi—ukupholisha ngoomatshini kuyadingeka ukususa imingxunya emincinci yokusila, ukunciphisa umonakalo womphezulu, ukususa imikrwelo, ukuqhekeka, kunye neziphene zamaxolo eorenji, ukunciphisa uburhabaxa bomphezulu, ukuphucula ubuthe tyaba, kunye nokuphucula umgangatho womphezulu.

Ukuze ufumane umphezulu ocoliweyo osemgangathweni ophezulu, kufuneka:

Lungisa iintlobo ze-abrasive,

Nciphisa ubungakanani bamasuntswana,

Lungiselela iiparameter zenkqubo,

Khetha izinto zokupholisha kunye neepads ezinobunzima obaneleyo.

Umfanekiso 7 ubonisa ukuba ukupolisha okumacala omabini nge-1 μm abrasives kunokulawula ukuthamba kunye nokuguquguquka kobukhulu ngaphakathi kwe-10 μm, kwaye kunciphise ukurhabaxa komphezulu ukuya malunga ne-0.25 nm.

3.2 Ukupholisha oomatshini beKhemikhali (i-CMP)

I-Chemical Mechanical Polishing (CMP) idibanisa ukukrazulwa kwamasuntswana acwebezelayo kunye nokugrumba kwamasuntswana ukuze kwenziwe umphezulu ogudileyo, ocwangcisiweyo kwizinto ezicutshungulwayo. Umgaqo osisiseko ngulo:

Kwenzeka i-chemical reaction phakathi kwe-polishing slurry kunye nomphezulu we-wafer, nto leyo eyenza umaleko othambileyo.

Ukungqubana phakathi kwamasuntswana arhabaxa kunye nomaleko othambileyo kususa izinto.

Iingenelo ze-CMP:

Iyayoyisa imiqobo yokupholisha ngoomatshini okanye ngeekhemikhali kuphela,

Ifezekisa ucwangciso lwehlabathi kunye nolwasekuhlaleni,

Ivelisa iindawo ezithe tyaba kakhulu nezirhabaxa,

Ayishiyi monakalo kumphezulu okanye ngaphantsi komhlaba.

Ngokweenkcukacha:

I-wafer ihamba ngokumalunga nephedi yokupolisha phantsi koxinzelelo.

Ii-abrasives zesikali se-nanometer (umz., i-SiO₂) kwi-slurry zithatha inxaxheba ekuchebeni, zenze buthathaka ii-Si-C covalent bonds kunye nokuphucula ukususwa kwezinto.

Iintlobo zeeNdlela ze-CMP:

Ukupholisha Okungarhawuzelelwanga Kwasimahla: Ii-Abrasives (umz., i-SiO₂) zixhonywe kwi-slurry. Ukususwa kwezinto kwenzeka ngokurhawuzelelwa kwemizimba emithathu (i-wafer-pad-abrasive). Ubungakanani be-Abrasive (ngesiqhelo yi-60–200 nm), i-pH, kunye nobushushu kufuneka kulawulwe ngokuchanekileyo ukuphucula ukufana.

Ukupholisha Okungaguqukiyo: Ii-Abrasives zifakwa kwiphedi yokupholisha ukuthintela ukuhlangana—zilungele ukusetyenzwa ngokuchanekileyo.

Ukucoca Emva kokuPolisha:

Iiwafers ezikhazimlisiweyo ziya kudlula:

Ukucoca ngamakhemikhali (kubandakanya amanzi e-DI kunye nokususwa kwentsalela ye-slurry),

Ukuhlamba ngamanzi e-DI, kunye

Ukomisa i-nitrogen eshushu

ukunciphisa ungcoliseko lomphezulu.

Umgangatho woMphezulu kunye nokusebenza

Uburhabaxa bomphezulu bunokwehliswa bube yi-Ra < 0.3 nm, nto leyo ehlangabezana neemfuno ze-semiconductor epitaxy.

Ukucwangciswa kweHlabathi: Ukudibanisa ukuthambisa iikhemikhali kunye nokususwa ngoomatshini kunciphisa imikrwelo kunye nokugrumba okungalinganiyo, okuphumelela ngaphezu kweendlela ezicocekileyo zoomatshini okanye zeekhemikhali.

Ukusebenza kakuhle okuphezulu: Ifanelekile kwizinto eziqinileyo nezibuthathaka ezifana neSiC, kunye namazinga okususa izinto angaphezu kwe-200 nm/h.

Ezinye iindlela zokuCoca ezisakhasayo

Ukongeza kwi-CMP, kuye kwacetyiswa ezinye iindlela, kuquka:

Ukupholisha nge-electrochemical, ukupholisha okanye ukukrola okuncediswa yiCatalyst, kunye

Ukupholisha nge-tribochemical.

Nangona kunjalo, ezi ndlela zisesekwinqanaba lophando kwaye ziye zaphuhliswa kancinci kancinci ngenxa yeempawu zezinto eziluncedo zeSiC.

Ekugqibeleni, ukucubungula i-SiC yinkqubo ethatha kancinci yokunciphisa i-warpage kunye noburhabaxa ukuphucula umgangatho womphezulu, apho ulawulo loburhabaxa kunye noburhabaxa lubaluleke kakhulu kulo lonke inqanaba.

Itekhnoloji yokucubungula

Ngexesha lesigaba sokusila i-wafer, i-diamond slurry enobukhulu obahlukeneyo bee-particle isetyenziselwa ukusila i-wafer iye kwindawo ethe tyaba neyomphezulu ofunekayo. Oku kulandelwa kukupholisha, kusetyenziswa iindlela zokupholisha ngoomatshini nangeekhemikhali (CMP) ukuvelisa ii-wafers ze-silicon carbide (SiC) ezipholisiweyo ezingenamonakalo.

Emva kokupolisha, ii-wafer zeSiC zihlolwa ngononophelo lomgangatho kusetyenziswa izixhobo ezifana nee-optical microscopes kunye nee-X-ray diffractometers ukuqinisekisa ukuba zonke iiparameter zobugcisa ziyahlangabezana nemigangatho efunekayo. Okokugqibela, ii-wafers ezipolishayo ziyacocwa kusetyenziswa ii-arhente zokucoca ezikhethekileyo kunye namanzi acocekileyo kakhulu ukususa ungcoliseko lomphezulu. Emva koko zomiswa kusetyenziswa igesi ye-nitrogen ecocekileyo kakhulu kunye nee-spin dryers, zigqibezela yonke inkqubo yemveliso.

Emva kweminyaka yomzamo, kwenziwe inkqubela phambili enkulu ekucutshungulweni kwekristale enye yeSiC eTshayina. Ekhaya, iikristale enye ze-4H-SiC ezifakwe i-semi-insulating eziyi-100 mm ziye zaphuhliswa ngempumelelo, kwaye iikristale enye ze-4H-SiC kunye ne-6H-SiC zohlobo lwe-n ngoku zinokuveliswa ngokwamaqela. Iinkampani ezifana neTankeBlue kunye neTYST sele ziphuhlisile iikristale enye ze-150 mm SiC.

Ngokuphathelele ubuchwepheshe bokucubungula i-wafer ye-SiC, amaziko asekhaya aqale ahlola iimeko zenkqubo kunye neendlela zokusika, ukugaya, kunye nokupolisha ngekristale. Ayakwazi ukuvelisa iisampulu ezihlangabezana neemfuno zokwenza izixhobo. Nangona kunjalo, xa kuthelekiswa nemigangatho yamazwe ngamazwe, umgangatho wokucubungula umphezulu wee-wafer zasekhaya usasilele kakhulu. Kukho imiba eliqela:

Iingcamango zeSiC zamazwe ngamazwe kunye netekhnoloji yokucubungula zikhuselwe kakhulu kwaye azifumaneki lula.

Kukho ukunqongophala kophando lwethiyori kunye nenkxaso yokuphucula kunye nokwenza ngcono inkqubo.

Iindleko zokungenisa izixhobo kunye neenxalenye zangaphandle ziphezulu.

Uphando lwasekhaya malunga noyilo lwezixhobo, ukuchaneka kokucubungula, kunye nezixhobo lusabonisa izikhewu ezinkulu xa kuthelekiswa namanqanaba amazwe ngamazwe.

Okwangoku, uninzi lwezixhobo ezisetyenziswa ngokuchanekileyo eTshayina zithunyelwa kwamanye amazwe. Izixhobo zokuvavanya kunye neendlela nazo zifuna ukuphuculwa okungakumbi.

Ngokuqhubeka nophuhliso lwee-semiconductors zesizukulwana sesithathu, ububanzi be-SiC single crystal substrates buyanda ngokuthe chu, kunye neemfuno eziphezulu zomgangatho wokucubungula umphezulu. Itekhnoloji yokucubungula i-wafer ibe lelinye lamanyathelo anzima kakhulu kwezobuchwepheshe emva kokukhula kwe-SiC single crystal.

Ukuze kujongwane nemingeni ekhoyo ekucutshungulweni, kubalulekile ukufunda ngakumbi iindlela ezibandakanyekayo ekusikeni, ekugayeni nasekupolisheni, kunye nokupholisha iindlela ezifanelekileyo zenkqubo kunye neendlela zokwenza i-SiC wafer. Kwangaxeshanye, kuyimfuneko ukufunda kwiiteknoloji eziphambili zokucubungula zamazwe ngamazwe kunye nokusebenzisa iindlela zobugcisa bokuchwetheza obuchanekileyo kunye nezixhobo zobugcisa bokuvelisa ii-substrates ezikumgangatho ophezulu.

Njengoko ubungakanani be-wafer bukhula, ubunzima bokukhula kwekristale kunye nokucubungula buyanda. Nangona kunjalo, ukusebenza kakuhle kokuvelisa izixhobo ezisezantsi kuphucuka kakhulu, kwaye ixabiso leyunithi liyancitshiswa. Okwangoku, abathengisi abaphambili be-SiC wafer kwihlabathi liphela banikezela ngeemveliso eziqala kwii-intshi ezi-4 ukuya kwii-intshi ezi-6 ububanzi. Iinkampani eziphambili ezifana neCree kunye ne-II-VI sele ziqalile ukucwangcisa uphuhliso lwemigca yemveliso ye-wafer ye-SiC ye-intshi ezi-8.