Mkhalidwe ndi Zochitika Zamakono za Ukadaulo Wopangira SiC Wafer

Monga chipangizo cha m'badwo wachitatu cha semiconductor substrate,silicon carbide (SiC)Galasi imodzi ili ndi mwayi waukulu wogwiritsa ntchito popanga zipangizo zamagetsi zamagetsi zomwe zimakhala ndi ma frequency ambiri komanso mphamvu zambiri. Ukadaulo wokonza SiC umagwira ntchito yofunika kwambiri popanga zipangizo zapamwamba kwambiri. Nkhaniyi ikufotokoza momwe kafukufuku wamakono wa ukadaulo wokonza SiC ku China ndi kunja, kusanthula ndikuyerekeza njira zodulira, kupukuta, ndi kupukuta, komanso momwe zinthu zilili pa kusalala kwa wafer ndi kukhwima kwa pamwamba. Ikufotokozanso zovuta zomwe zilipo pakupanga wafer wafer wa SiC ndikukambirana njira zamtsogolo zopititsira patsogolo.

Silikoni kabide (SiC)Ma wafer ndi zinthu zofunika kwambiri pa zipangizo za semiconductor za m'badwo wachitatu ndipo ali ndi kufunika kwakukulu komanso kuthekera kwa msika m'magawo monga ma microelectronics, magetsi, ndi magetsi a semiconductor. Chifukwa cha kuuma kwakukulu komanso kukhazikika kwa mankhwala aMakristalo amodzi a SiC, njira zachikhalidwe zopangira ma semiconductor sizoyenera kwambiri pamakina awo opangira. Ngakhale makampani ambiri apadziko lonse lapansi achita kafukufuku wambiri pa kukonza makristasi a SiC single crystals ovuta kwambiri, matekinoloje oyenerera amasungidwa mwachinsinsi kwambiri.

M'zaka zaposachedwapa, China yawonjezera khama pakupanga zipangizo ndi zipangizo za SiC single crystal. Komabe, kupita patsogolo kwa ukadaulo wa zipangizo za SiC mdziko muno pakadali pano kukulepheretsedwa ndi zoletsa paukadaulo wokonza ndi ubwino wa wafer. Chifukwa chake, ndikofunikira kuti China ikonze luso lokonza SiC kuti iwonjezere ubwino wa zinthu za SiC single crystal substrates ndikukwaniritsa kugwiritsidwa ntchito kwake kothandiza komanso kupanga zinthu zambiri.

Njira zazikulu zokonzera zinthu ndi izi: kudula → kupukuta kolimba → kupukuta bwino → kupukuta kosalala (kupukuta kwamakina) → kupukuta bwino (kupukuta kwamakina kwa mankhwala, CMP) → kuyang'anira.

Kudula Makristalo Okhaokha a SiC

Mu kukonza kwaMakristalo amodzi a SiC, kudula ndi gawo loyamba komanso lofunika kwambiri. Kusiyanasiyana kwa waya, kupindika, ndi makulidwe onse (TTV) komwe kumachitika chifukwa cha kudulako kumatsimikizira ubwino ndi magwiridwe antchito opera ndi kupukuta pambuyo pake.

Zipangizo zodulira zitha kugawidwa m'magulu malinga ndi mawonekedwe ake m'magawo awiri: macheka amkati mwa diameter ya diamondi (ID), macheka akunja a diameter (OD), macheka a band, ndi macheka a waya. Macheka a waya, nawonso, amatha kugawidwa m'magulu malinga ndi mtundu wawo woyenda m'ma waya obwerezabwereza komanso ozungulira (osatha). Kutengera ndi njira yodulira ya abrasive, njira zodulira waya zitha kugawidwa m'mitundu iwiri: kudula waya kwaulere ndi kudula waya wa diamondi molimba.

1.1 Njira Zachikhalidwe Zodulira

Kuzama kwa kudula kwa macheka akunja kwa diameter (OD) kumachepetsedwa ndi kukula kwa tsamba. Panthawi yodula, tsamba limakhala logwedezeka komanso lopotoka, zomwe zimapangitsa kuti phokoso likhale lalikulu komanso kusalimba bwino. Macheka amkati mwa diameter (ID) amagwiritsa ntchito ma diamondi abrasives mkati mwa tsamba ngati m'mphepete mwa tsamba. Macheka amenewa amatha kukhala opyapyala ngati 0.2 mm. Podula, tsamba la ID limazungulira mwachangu pomwe zinthu zomwe ziyenera kudulidwa zimayenda mozungulira poyerekeza ndi pakati pa tsamba, zomwe zimapangitsa kuti zidule izi zitheke.

Macheka a diamondi amafunika kuyimitsidwa pafupipafupi komanso kusinthidwa, ndipo liwiro lodula ndi lotsika kwambiri—nthawi zambiri silingapitirire 2 m/s. Amavutikanso ndi kuwonongeka kwakukulu kwa makina komanso ndalama zambiri zosamalira. Chifukwa cha m'lifupi mwa tsamba la chitsulo, utali wodulira sungakhale wochepa kwambiri, ndipo kudula magawo ambiri sikungatheke. Zipangizo zachikhalidwe zodulira izi zimachepetsedwa ndi kulimba kwa maziko ndipo sizingadulidwe mokhota kapena kukhala ndi ma radii ozungulira ochepa. Amatha kudula molunjika, kupanga mizere yayikulu, kukhala ndi chiwongola dzanja chochepa, motero sali oyenera kudula.Makristalo a SiC.

1.2 Kudula Mawaya Aakulu Opanda Ufulu

Njira yodulira waya pogwiritsa ntchito waya wodula popanda kugwiritsa ntchito waya imagwiritsa ntchito waya woyenda mwachangu kuti inyamule matope kupita ku kerf, zomwe zimathandiza kuti zinthu zichotsedwe. Imagwiritsa ntchito kapangidwe kobwerezabwereza ndipo pakadali pano ndi njira yokhwima komanso yogwiritsidwa ntchito kwambiri podula bwino silicon imodzi ya kristalo. Komabe, kugwiritsa ntchito kwake podula SiC sikunaphunziridwe mokwanira.

Macheka a waya opangidwa mwaulere amatha kukonza ma wafer okhala ndi makulidwe osakwana 300 μm. Amapereka kutayika kochepa kwa kerf, nthawi zambiri amayambitsa kusweka, ndipo amachititsa kuti pamwamba pakhale bwino. Komabe, chifukwa cha njira yochotsera zinthuzo—kutengera kugwedezeka ndi kupindika kwa ma abrasives—pamwamba pa wafer pamakhala kupsinjika kwakukulu, ming'alu yaying'ono, ndi kuwonongeka kwakukulu. Izi zimapangitsa kuti wafer igwedezeke, zimapangitsa kuti zikhale zovuta kuwongolera kulondola kwa mawonekedwe a pamwamba, ndikuwonjezera katundu pazotsatira zokonzera.

Kapangidwe kake ka kudula kamakhudzidwa kwambiri ndi matope; ndikofunikira kusunga kuthwa kwa ma abrasives ndi kuchuluka kwa matope. Kukonza matope ndi kubwezeretsanso zinthu n'kokwera mtengo. Podula ma ingots akuluakulu, ma abrasives amavutika kulowa m'ma kerfs akuya komanso aatali. Pansi pa kukula komweko kwa tinthu ta abrasive, kutayika kwa matope kumakhala kwakukulu kuposa kwa macheka a waya okhazikika.

1.3 Yokhazikika Yokhala ndi Waya wa Daimondi Wodula Waya Wambiri

Macheka a waya a diamondi okhazikika nthawi zambiri amapangidwa poika tinthu ta diamondi pa waya wachitsulo pogwiritsa ntchito njira zamagetsi, sintering, kapena resin bonding. Macheka a waya a diamondi opangidwa ndi magetsi amapereka ubwino monga ma kerf opapatiza, khalidwe labwino la zidutswa, kugwira ntchito bwino, kuchepetsa kuipitsidwa, komanso kuthekera kodula zinthu zolimba kwambiri.

Chocheka cha waya wa diamondi chopangidwa ndi ma elekitironi ndi njira yomwe imagwiritsidwa ntchito kwambiri podula SiC. Chithunzi 1 (sichikuwonetsedwa pano) chikuwonetsa kusalala kwa pamwamba pa ma wafer a SiC odulidwa pogwiritsa ntchito njira iyi. Pamene kudula kukupitirira, wafer warpage imawonjezeka. Izi zili choncho chifukwa malo olumikizirana pakati pa waya ndi zinthu amawonjezeka pamene waya ukutsika, zomwe zimawonjezera kukana ndi kugwedezeka kwa waya. Waya ukafika pa mulifupi waukulu wa wafer, kugwedezeka kumakhala pachimake, zomwe zimapangitsa kuti pakhale warpage yayikulu.

Pamapeto pake podula, chifukwa cha waya womwe ukuthamanga, kuyenda mokhazikika kwa liwiro, kuchepa kwa mphamvu, kuyima, ndi kutembenuka, pamodzi ndi zovuta kuchotsa zinyalala ndi choziziritsira, ubwino wa pamwamba pa wafer umachepa. Kusinthasintha kwa waya ndi liwiro, komanso tinthu tating'onoting'ono ta diamondi pa waya, ndizomwe zimayambitsa kukwawa pamwamba.

1.4 Ukadaulo Wopatukana ndi Anthu Ozizira

Kulekanitsa makhiristo a SiC amodzi mozizira ndi njira yatsopano yopangira zinthu za semiconductor za m'badwo wachitatu. M'zaka zaposachedwa, yakopa chidwi chachikulu chifukwa cha zabwino zake zodziwika bwino pakukweza zokolola ndikuchepetsa kutayika kwa zinthu. Ukadaulowu ukhoza kusanthulidwa kuchokera mbali zitatu: mfundo yogwirira ntchito, kayendedwe ka njira, ndi zabwino zazikulu.

Kuzindikira Kuyang'ana kwa Makristalo ndi Kupera kwa Makulidwe Akunja: Musanayambe kukonza, kuyang'ana kwa makristalo a ingot ya SiC kuyenera kudziwika. Kenako ingot imapangidwa kukhala mawonekedwe a cylindrical (omwe nthawi zambiri amatchedwa SiC puck) kudzera mu kugaya kwa makulidwe akunja. Gawoli limayala maziko a kudula ndi kudula kotsatira.

Kudula Mawaya Ambiri: Njirayi imagwiritsa ntchito tinthu tomwe timadula pamodzi ndi mawaya odulira kuti tidule ingot yozungulira. Komabe, imakhala ndi vuto lalikulu la kutayika kwa kerf komanso kusafanana kwa pamwamba.

Ukadaulo Wodula ndi Laser: Laser imagwiritsidwa ntchito kupanga wosanjikiza wosinthidwa mkati mwa kristalo, pomwe zidutswa zopyapyala zimatha kuchotsedwa. Njira iyi imachepetsa kutayika kwa zinthu ndikuwonjezera magwiridwe antchito opangira, zomwe zimapangitsa kuti ikhale njira yatsopano yodalirika yodulira SiC wafer.

Kukonza Njira Zodulira

Kudula Mawaya Ambiri Okhazikika: Iyi ndi ukadaulo wodziwika bwino pakadali pano, woyenera bwino mawonekedwe a SiC olimba kwambiri.

Makina Otulutsa Magesi (EDM) ndi Ukadaulo Wolekanitsa Anthu Ozizira: Njirazi zimapereka mayankho osiyanasiyana ogwirizana ndi zofunikira zinazake.

Njira Yopukutira: Ndikofunikira kuti pakhale kulinganiza bwino kuchuluka kwa zinthu zomwe zachotsedwa komanso kuwonongeka kwa pamwamba. Kupukutira kwa Mankhwala Opangidwa ndi Mankhwala (CMP) kumagwiritsidwa ntchito kuti pakhale kufanana kwa pamwamba.

Kuwunika Nthawi Yeniyeni: Njira zamakono zowunikira pa intaneti zayambitsidwa kuti ziwunikire kuuma kwa pamwamba nthawi yeniyeni.

Kudula kwa Laser: Njirayi imachepetsa kutayika kwa kerf ndikufupikitsa nthawi yogwiritsira ntchito, ngakhale kuti malo omwe akhudzidwa ndi kutentha akadali ovuta.

Ukadaulo Wopangira Zinthu Zosakanikirana: Kuphatikiza njira zamakina ndi mankhwala kumawonjezera luso lopangira zinthu.

Ukadaulo uwu wagwiritsidwa ntchito kale m'mafakitale. Mwachitsanzo, Infineon adapeza SILTECTRA ndipo tsopano ali ndi ma patent ofunikira omwe amathandizira kupanga ma wafer a mainchesi 8. Ku China, makampani monga Delong Laser apeza mphamvu yotulutsa ma wafer 30 pa ingot iliyonse yopangira ma wafer a mainchesi 6, zomwe zikuyimira kusintha kwa 40% poyerekeza ndi njira zachikhalidwe.

Pamene kupanga zida zapakhomo kukuchulukirachulukira, ukadaulo uwu ukuyembekezeka kukhala njira yodziwika bwino yogwiritsira ntchito SiC substrate. Chifukwa cha kukula kwa zida za semiconductor, njira zodulira zachikhalidwe zatha ntchito. Pakati pa zosankha zomwe zilipo pano, ukadaulo wodulira waya wa diamondi ukuwonetsa mwayi wogwiritsa ntchito bwino kwambiri. Kudula kwa laser, monga njira yatsopano, kumapereka zabwino zazikulu ndipo kukuyembekezeka kukhala njira yayikulu yodulira mtsogolo.

2,Kupera kwa SiC Single Crystal

Monga choyimira ma semiconductors a m'badwo wachitatu, silicon carbide (SiC) imapereka ubwino waukulu chifukwa cha bandgap yake yayikulu, mphamvu yamagetsi yotsika kwambiri, liwiro la ma elekitironi ochulukirapo, komanso kutentha kwabwino kwambiri. Zinthu izi zimapangitsa SiC kukhala yopindulitsa kwambiri pakugwiritsa ntchito mphamvu yamagetsi yapamwamba (monga 1200V). Ukadaulo wokonza ma substrates a SiC ndi gawo lofunikira kwambiri popanga chipangizocho. Ubwino wa pamwamba ndi kulondola kwa substrate kumakhudza mwachindunji ubwino wa epitaxial layer ndi magwiridwe antchito a chipangizo chomaliza.

Cholinga chachikulu cha njira yopera ndikuchotsa zizindikiro za macheka pamwamba ndi zigawo zowonongeka zomwe zimachitika podula, komanso kukonza kusintha komwe kumachitika chifukwa cha njira yodula. Popeza SiC ndi yolimba kwambiri, kugaya kumafuna kugwiritsa ntchito zinthu zolimba monga boron carbide kapena diamondi. Kupera kwachizolowezi nthawi zambiri kumagawidwa m'magulu awiri: kupukuta kosalala ndi kupukuta pang'ono.

2.1 Kupera Kolimba ndi Kosalala

Kupera kumatha kugawidwa m'magulu kutengera kukula kwa tinthu tating'onoting'ono:

Kupera Kolimba: Kumagwiritsa ntchito zinthu zazikulu zochotsera macheka ndi zinthu zowonongeka zomwe zimachitika poduladula, zomwe zimapangitsa kuti ntchito yokonza zinthu izi ikhale yabwino.

Kupera Mopyapyala: Kumagwiritsa ntchito zinthu zopyapyala zochepetsera kuwononga komwe kwatsala chifukwa cha kupera mopyapyala, kuchepetsa kuuma kwa pamwamba, ndikuwonjezera ubwino wa pamwamba.

Opanga zinthu zambiri za SiC m'nyumba amagwiritsa ntchito njira zazikulu zopangira. Njira yodziwika bwino imaphatikizapo kupukutira mbali ziwiri pogwiritsa ntchito mbale yachitsulo yopangidwa ndi chitsulo ndi slurry ya monocrystalline diamond. Njirayi imachotsa bwino gawo lowonongeka lomwe latsala ndi kudula waya, kukonza mawonekedwe a wafer, ndikuchepetsa TTV (Total Thickness Variation), Bow, ndi Warp. Kuchuluka kwa zinthuzo kumakhala kokhazikika, nthawi zambiri kumafika 0.8–1.2 μm/min. Komabe, pamwamba pa wafer yomwe imachokera ndi yosalala komanso yolimba kwambiri—nthawi zambiri pafupifupi 50 nm—zomwe zimapangitsa kuti pakhale kufunikira kwakukulu pa njira zotsukira zotsatira.

2.2 Kupera Mbali Imodzi

Kupera mbali imodzi kumakonza mbali imodzi yokha ya wafer nthawi imodzi. Panthawiyi, wafer imayikidwa sera pa mbale yachitsulo. Pakagwiritsidwa ntchito mphamvu, gawo lapansi limasinthasintha pang'ono, ndipo pamwamba pake pamakhala pathyathyathya. Pambuyo popera, pansi pake pamakhala pamlingo wofanana. Kupanikizika kukachotsedwa, pamwamba pake pamakhala kuti pakhale mawonekedwe ake oyamba, zomwe zimakhudzanso pansi pomwe pamakhala pansi kale—zomwe zimapangitsa kuti mbali zonse ziwiri zipindike ndikuwonongeka.

Komanso, mbale yopukusira imatha kupindika pakapita nthawi yochepa, zomwe zimapangitsa kuti wafer ikhale yopyapyala. Kuti mbaleyo ikhale yopyapyala, pamafunika kuyika pulasitiki pafupipafupi. Chifukwa cha ntchito yochepa komanso kusapyapyala bwino kwa wafer, kupukusira mbali imodzi sikoyenera kupangidwa mochuluka.

Kawirikawiri, mawilo opukutira #8000 amagwiritsidwa ntchito popukutira pang'ono. Ku Japan, njirayi ndi yokhwima kwambiri ndipo imagwiritsanso ntchito mawilo opukutira #30000. Izi zimathandiza kuti pamwamba pa mawafer okonzedwawo pakhale pansi pa 2 nm, zomwe zimapangitsa kuti mawaferwo akhale okonzeka ku CMP yomaliza (Chemical Mechanical Polishing) popanda kukonzedwa kwina.

2.3 Ukadaulo Wochepetsa Mbali Imodzi

Ukadaulo Wochepetsa Mbali Imodzi wa Diamond ndi njira yatsopano yopera mbali imodzi. Monga momwe zasonyezedwera pa Chithunzi 5 (sichikuwonetsedwa pano), njirayi imagwiritsa ntchito mbale yopera yokhala ndi diamondi. Wafer imakhazikika kudzera mu vacuum adsorption, pomwe wafer ndi gudumu lopera la diamondi zimazungulira nthawi imodzi. Gudumu lopera limatsika pang'onopang'ono kuti lichepetse wafer kukhala makulidwe oyenera. Mbali imodzi ikamalizidwa, wafer imasinthidwa kuti igwire mbali inayo.

Pambuyo pochepetsa, wafer wa 100 mm ukhoza kukwaniritsa:

Uta < 5 μm

TTV < 2 μm

Kukhwima kwa pamwamba < 1 nm

Njira yopangira chidebe chimodzi iyi imapereka kukhazikika kwakukulu, kusinthasintha kwabwino, komanso kuchotsera zinthu mwachangu. Poyerekeza ndi kupukusa kwachikhalidwe kwa mbali ziwiri, njira iyi imakulitsa luso lopukusa ndi kupitirira 50%.

2.4 Kupera Mbali Ziwiri

Kupera mbali zonse ziwiri kumagwiritsa ntchito mbale yopera pamwamba ndi pansi kuti ipere mbali zonse ziwiri za substrate nthawi imodzi, kuonetsetsa kuti pamwamba pake pali bwino kwambiri mbali zonse ziwiri.

Panthawiyi, mbale zopukutira zimayamba kukanikiza pamalo okwera kwambiri a workpiece, zomwe zimapangitsa kuti zinthu zisinthe pang'onopang'ono komanso kuti zinthuzo zichotsedwe pang'onopang'ono pamalopo. Pamene malo okwera akufanana, kukanikiza kwa substrate kumakhala kofanana pang'onopang'ono, zomwe zimapangitsa kuti malo onse pamwamba ndi pansi asinthe mofanana. Izi zimathandiza kuti malo onse apamwamba ndi otsika apukutidwe mofanana. Kupukutira kukatha ndipo kukanikiza kukatulutsidwa, gawo lililonse la substrate limabwerera mofanana chifukwa cha kukanikiza komwe kunakumana nako. Izi zimapangitsa kuti pakhale kupindika kochepa komanso kusalala bwino.

Kukhwima kwa pamwamba pa wafer pambuyo popera kumadalira kukula kwa tinthu tomwe timapera—tinthu tating'onoting'ono timatulutsa malo osalala. Mukagwiritsa ntchito ma abrasives a 5 μm popera mbali ziwiri, kusiyana kwa wafer ndi makulidwe kumatha kulamulidwa mkati mwa 5 μm. Miyeso ya Atomic Force Microscopy (AFM) imasonyeza kukhwima kwa pamwamba (Rq) kwa pafupifupi 100 nm, ndi maenje opera mpaka 380 nm akuya komanso zizindikiro zowoneka bwino zomwe zimachitika chifukwa cha kuphwanya.

Njira yapamwamba kwambiri imaphatikizapo kupukutira mbali ziwiri pogwiritsa ntchito mapepala a thovu la polyurethane pamodzi ndi slurry ya diamondi ya polycrystalline. Njirayi imapanga ma wafer okhala ndi kuuma pang'ono pamwamba, zomwe zimapangitsa kuti Ra < 3 nm, zomwe zimathandiza kwambiri pakupukuta kwa SiC substrates pambuyo pake.

Komabe, kukanda pamwamba sikunathetsedwebe. Kuphatikiza apo, diamondi ya polycrystalline yomwe imagwiritsidwa ntchito panjirayi imapangidwa kudzera mu kupanga zinthu zophulika, zomwe zimakhala zovuta kwambiri paukadaulo, sizipanga zinthu zambiri, komanso zimakhala zodula kwambiri.

Kupukuta kwa Makristalo Okhaokha a SiC

Kuti pakhale malo opukutidwa bwino kwambiri pa ma wafer a silicon carbide (SiC), kupukuta kuyenera kuchotsa kwathunthu maenje opukutira ndi ma undulating a pamwamba a nanometer. Cholinga chake ndikupanga malo osalala, opanda chilema opanda kuipitsidwa kapena kuwonongeka, osawonongeka pansi pa nthaka, komanso osatsala ndi kupsinjika kwa pamwamba.

3.1 Kupukuta kwa Makina ndi CMP ya SiC Wafers

Pambuyo pa kukula kwa ingot ya SiC single crystal, zolakwika pamwamba zimalepheretsa kuti isagwiritsidwe ntchito mwachindunji pakukula kwa epitaxial. Chifukwa chake, kukonza kwina kumafunika. Ingot imapangidwa koyamba kukhala mawonekedwe ozungulira kudzera mu kuzungulira, kenako imadulidwa kukhala ma wafer pogwiritsa ntchito kudula waya, kutsatiridwa ndi kutsimikizira kwa kristalographic. Kupukuta ndi gawo lofunikira kwambiri pakukweza mtundu wa wafer, kuthana ndi kuwonongeka komwe kungachitike chifukwa cha zolakwika pakukula kwa kristalo ndi njira zoyendetsera kale.

Pali njira zinayi zazikulu zochotsera zigawo zowononga pamwamba pa SiC:

Kupukuta kwa makina: Kosavuta koma kumasiya mikwingwirima; koyenera kupukuta koyamba.

Kupukuta kwa Makina Opangira Mankhwala (CMP): Kuchotsa mikwingwirima kudzera mu etching ya mankhwala; koyenera kupukuta molondola.

Kudula kwa haidrojeni: Kumafuna zida zovuta, zomwe zimagwiritsidwa ntchito kwambiri mu njira za HTCVD.

Kupukuta kothandizidwa ndi plasma: N'kovuta ndipo sikugwiritsidwa ntchito kawirikawiri.

Kupukuta kwa makina okha kumayambitsa mikwingwirima, pomwe kupukuta kwa mankhwala okha kungayambitse kuphwanya kosagwirizana. CMP imaphatikiza zabwino zonse ziwiri ndipo imapereka yankho labwino komanso lotsika mtengo.

Mfundo Yogwirira Ntchito ya CMP

CMP imagwira ntchito pozungulira wafer pansi pa mphamvu yokhazikika motsutsana ndi chopukutira chozungulira. Kuyenda kofanana kumeneku, kuphatikiza ndi kusweka kwa makina kuchokera ku zotsukira zazikulu kwambiri mu slurry ndi mphamvu ya mankhwala ya zinthu zosinthika, zimapangitsa kuti pakhale kulinganiza kwa pamwamba.

Zipangizo zofunika kwambiri:

Kupukuta matope: Muli zinthu zopukutira ndi zinthu zina zoyeretsera.

Pedi yopukutira: Imawonongeka ikagwiritsidwa ntchito, zomwe zimachepetsa kukula kwa machubu ndi kufalikira bwino kwa matope. Kuvala kuvala nthawi zonse, nthawi zambiri pogwiritsa ntchito chosungira cha diamondi, kumafunika kuti kubwezeretse kuuma.

Njira Yachizolowezi ya CMP

Wosakhazikika: 0.5 μm diamondi slurry

Kukhwima kwa pamwamba pa cholinga: ~0.7 nm

Kupukuta Makina a Mankhwala:

Zipangizo zopukutira: AP-810 chopukutira cha mbali imodzi

Kupanikizika: 200 g/cm²

Liwiro la mbale: 50 rpm

Liwiro la chogwirira cha ceramic: 38 rpm

Kapangidwe ka slurry:

SiO₂ (30 wt%, pH = 10.15)

0–70 wt% H₂O₂ (30 wt%, reagent grade)

Sinthani pH kufika pa 8.5 pogwiritsa ntchito 5 wt% KOH ndi 1 wt% HNO₃

Kuthamanga kwa madzi oundana: 3 L/mphindi, kuzunguliridwanso

Njirayi imawongolera bwino mtundu wa SiC wafer ndipo imakwaniritsa zofunikira pa njira zotsatizana.

Mavuto aukadaulo pa kupukuta makina

SiC, monga semiconductor yolumikizira mbali zonse ziwiri, imagwira ntchito yofunika kwambiri mumakampani amagetsi. Ndi mphamvu zake zakuthupi komanso zamakemikolo, makhiristo a SiC amodzi ndi oyenera malo ovuta kwambiri, monga kutentha kwambiri, kuchuluka kwa ma frequency ambiri, mphamvu zambiri, komanso kukana ma radiation. Komabe, kulimba kwake komanso kufooka kwake kumabweretsa mavuto akulu pakupukuta ndi kupukuta.

Monga opanga otsogola padziko lonse lapansi omwe akusintha kuchoka pa ma wafer a mainchesi 6 kupita ku mainchesi 8, mavuto monga kusweka ndi kuwonongeka kwa ma wafer panthawi yokonza zinthu akhala akuonekera kwambiri, zomwe zakhudza kwambiri phindu. Kuthana ndi mavuto aukadaulo a ma substrates a mainchesi 8 SiC tsopano ndi chizindikiro chofunikira kwambiri pakupita patsogolo kwa makampaniwa.

Mu nthawi ya mainchesi 8, kukonza ma wafer a SiC kumakumana ndi mavuto ambiri:

Kukulitsa kwa ma wafer ndikofunikira kuti kuwonjezere kutulutsa kwa chip pa gulu lililonse, kuchepetsa kutayika kwa m'mphepete, komanso kuchepetsa ndalama zopangira—makamaka chifukwa cha kufunikira kwakukulu kwa magalimoto amagetsi.

Ngakhale kukula kwa makristaro a SiC amodzi a mainchesi 8 kwakula, njira zogwirira ntchito kumbuyo monga kupukuta ndi kupukuta zikukumana ndi zovuta, zomwe zimapangitsa kuti pakhale zokolola zochepa (40-50%) zokha.

Ma wafer akuluakulu amakumana ndi kugawa kwa kupanikizika kovuta kwambiri, zomwe zimapangitsa kuti pakhale zovuta pokonza kupanikizika ndi kusinthasintha kwa zokolola.

Ngakhale kuti makulidwe a ma wafer a mainchesi 8 akuyandikira kukula kwa ma wafer a mainchesi 6, amatha kuwonongeka mosavuta akamayendetsedwa chifukwa cha kupsinjika ndi kupindika.

Pofuna kuchepetsa kupsinjika, kupotoka, ndi ming'alu yokhudzana ndi kudula, kudula kwa laser kukugwiritsidwa ntchito kwambiri. Komabe:

Ma laser a kutalika kwa mafunde amawononga kutentha.

Ma laser afupiafupi amapanga zinyalala zolemera ndikukulitsa gawo lowonongeka, zomwe zimapangitsa kuti kupukuta kukhale kovuta.

Ntchito Yopukutira Makina ya SiC

Njira yonse yogwirira ntchito ikuphatikizapo:

Kudula molunjika

Kupera kolimba

Kupera bwino

Kupukuta makina

Kupukuta kwa Makina Opangira Mankhwala (CMP) monga gawo lomaliza

Kusankha njira ya CMP, kapangidwe ka njira yogwirira ntchito, ndi kukonza bwino magawo ndikofunikira kwambiri. Pakupanga ma semiconductor, CMP ndiye gawo lofunikira popanga ma SiC wafers okhala ndi malo osalala kwambiri, opanda chilema, komanso opanda kuwonongeka, omwe ndi ofunikira pakukula kwa epitaxial kwapamwamba.

(a) Chotsani ingot ya SiC kuchokera pa choyimitsira;

(b) Chitani mawonekedwe oyamba pogwiritsa ntchito kupukusira kwa dayamita yakunja;

(c) Dziwani momwe kristalo imayendera pogwiritsa ntchito ma flats kapena notches;

(d) Dulani ingot m'ma wafers opyapyala pogwiritsa ntchito mawaya ambiri odulira;

(e) Pezani malo osalala ngati galasi kudzera mu njira zopukutira ndi kupukuta.

Mukamaliza njira zingapo zokonzera, m'mphepete mwa SiC wafer nthawi zambiri mumakhala wakuthwa, zomwe zimawonjezera chiopsezo cha kusweka pogwira ntchito kapena kugwiritsa ntchito. Kuti mupewe kusweka kotere, kupukuta m'mphepete kumafunika.

Kuwonjezera pa njira zachikhalidwe zodulira, njira yatsopano yokonzekera ma wafer a SiC imaphatikizapo ukadaulo womangira. Njira imeneyi imalola kupanga ma wafer mwa kumangirira wosanjikiza woonda wa SiC umodzi wa kristalo ku substrate yosiyana (substrate yothandizira).

Chithunzi 3 chikuwonetsa momwe ndondomekoyi ikuyendera:

Choyamba, gawo lolekanitsa limapangidwa pamlingo winawake pamwamba pa kristalo imodzi ya SiC kudzera mu kuyika kwa hydrogen ion kapena njira zina zofanana. Kenako kristalo imodzi ya SiC yokonzedwayo imalumikizidwa ku gawo lothandizira lathyathyathya ndikuyikidwa pansi pa kupanikizika ndi kutentha. Izi zimathandiza kusamutsa bwino ndi kulekanitsa gawo limodzi la SiC kupita ku gawo lothandizira.

Chigawo cha SiC cholekanitsidwacho chimakonzedwa pamwamba kuti chikhale chosalala ndipo chingagwiritsidwenso ntchito m'njira zotsatizana. Poyerekeza ndi kudula kwachikhalidwe kwa makristalo a SiC, njira iyi imachepetsa kufunikira kwa zipangizo zodula. Ngakhale kuti pali mavuto aukadaulo, kafukufuku ndi chitukuko zikupita patsogolo mwachangu kuti zitheke kupanga ma wafer otsika mtengo.

Popeza SiC ndi yolimba kwambiri komanso yokhazikika pa mankhwala—zomwe zimapangitsa kuti isagwere kutentha kwa chipinda—kupukuta kwa makina kumafunika kuti muchotse mabowo ophwanyidwa bwino, kuchepetsa kuwonongeka kwa pamwamba, kuchotsa mikwingwirima, maenje, ndi zolakwika za mapeyala a lalanje, kuchepetsa kukhwima kwa pamwamba, kukonza kusalala, ndikuwonjezera ubwino wa pamwamba.

Kuti malo opukutidwa bwino akhale abwino kwambiri, ndikofunikira:

Sinthani mitundu yokanda,

Chepetsani kukula kwa tinthu tating'onoting'ono,

Konzani magawo a ndondomeko,

Sankhani zinthu zopukutira ndi ma pad okhala ndi kuuma koyenera.

Chithunzi 7 chikuwonetsa kuti kupukuta mbali zonse ziwiri pogwiritsa ntchito zopukutira za 1 μm kumatha kuwongolera kusinthasintha kwa kusalala ndi makulidwe mkati mwa 10 μm, ndikuchepetsa kukhwima kwa pamwamba kufika pafupifupi 0.25 nm.

3.2 Kupukuta kwa Makina a Mankhwala (CMP)

Kupukuta kwa Mankhwala Opangira Mankhwala (CMP) kumaphatikiza kuphwanya tinthu tating'onoting'ono kwambiri ndi kupukuta kwa mankhwala kuti apange malo osalala, ozungulira pazinthu zomwe zikukonzedwa. Mfundo yaikulu ndi iyi:

Mankhwala amachitika pakati pa slurry yopukutira ndi pamwamba pa wafer, ndikupanga wosanjikiza wofewa.

Kukangana pakati pa tinthu tomwe timayabwa ndi wosanjikiza wofewa kumachotsa zinthuzo.

Ubwino wa CMP:

Imathetsa mavuto a kupukuta kwa makina kapena mankhwala okha,

Kukwaniritsa mapulani apadziko lonse lapansi komanso am'deralo,

Amapanga malo okhala ndi kusalala kwambiri komanso kukhwima kochepa,

Sichisiya kuwonongeka kulikonse pamwamba kapena pansi pa nthaka.

Mwatsatanetsatane:

Wafer imasuntha poyerekeza ndi chopukutira pansi pa kukakamizidwa.

Ma abrasives a nanometer-scale (monga SiO₂) mu slurry amagwira ntchito yodula, kufooketsa ma Si-C covalent bonds ndikuwonjezera kuchotsedwa kwa zinthu.

Mitundu ya Njira za CMP:

Kupukuta Kwaulere Kwa Abrasive: Ma abrasives (monga, SiO₂) amapachikidwa mu matope. Kuchotsa zinthu kumachitika kudzera mu kukwapula kwa matupi atatu (wafer-pad-abrasive). Kukula kwa abrasive (nthawi zambiri 60–200 nm), pH, ndi kutentha ziyenera kulamulidwa bwino kuti zikhale zofanana.

Kupukuta Kokhazikika kwa Abrasive: Ma abrasives amaikidwa mu pulasitiki kuti apewe kusonkhana—ndi abwino kwambiri pokonza molondola kwambiri.

Kuyeretsa Pambuyo Popukuta:

Ma wafer opukutidwa amachitidwa:

Kuyeretsa mankhwala (kuphatikizapo madzi a DI ndi kuchotsa zotsalira za slurry),

Kutsuka madzi a DI, ndi

Kuuma kwa nayitrogeni yotentha

kuchepetsa kuipitsidwa pamwamba.

Ubwino ndi Magwiridwe Abwino Pamwamba

Kukhwima kwa pamwamba kungachepe kufika pa Ra < 0.3 nm, kukwaniritsa zofunikira za semiconductor epitaxy.

Kupanga Mapulani Padziko Lonse: Kuphatikiza kwa kufewetsa mankhwala ndi kuchotsa makina kumachepetsa mikwingwirima ndi kupukuta kosafanana, zomwe zimagwira ntchito bwino kuposa njira zamakina kapena mankhwala.

Kugwiritsa Ntchito Bwino Kwambiri: Koyenera zinthu zolimba komanso zosweka ngati SiC, ndipo mphamvu zochotsera zinthuzo ndi zoposa 200 nm/h.

Njira Zina Zotulukirapo Zopukutira

Kuwonjezera pa CMP, njira zina zaperekedwa, kuphatikizapo:

Kupukuta kwamagetsi, kupukuta kapena kupukuta kothandizidwa ndi Catalyst, ndi

Kupukuta kwa tribochemical.

Komabe, njira izi zikadali mu gawo lofufuza ndipo zakula pang'onopang'ono chifukwa cha zinthu zovuta za SiC.

Pomaliza, kukonza SiC ndi njira yochepetsera pang'onopang'ono kupotoza ndi kukhwima kuti akonze bwino pamwamba, komwe kusalala ndi kuwongolera kukhwima ndikofunikira kwambiri pagawo lililonse.

Ukadaulo Wokonza

Pa nthawi yopukutira wafer, diamondi yokhala ndi tinthu tosiyanasiyana imagwiritsidwa ntchito kupukutira wafer mpaka kufika posalala komanso posalala pamwamba. Izi zimatsatiridwa ndi kupukuta, pogwiritsa ntchito njira zonse ziwiri zamakina komanso zamankhwala zopangira ma wafer opukutidwa a silicon carbide (SiC) osawonongeka.

Pambuyo popukuta, ma wafer a SiC amayesedwa bwino kwambiri pogwiritsa ntchito zida monga ma microscope optical ndi ma X-ray diffractometers kuti atsimikizire kuti zonse zaukadaulo zikukwaniritsa miyezo yofunikira. Pomaliza, ma wafer opukutidwa amatsukidwa pogwiritsa ntchito zotsukira zapadera ndi madzi oyera kwambiri kuti achotse zodetsa pamwamba. Kenako amaumitsa pogwiritsa ntchito mpweya wa nayitrogeni woyera kwambiri komanso zowumitsa zozungulira, zomwe zimamaliza ntchito yonse yopanga.

Pambuyo pa zaka zambiri zoyeserera, kupita patsogolo kwakukulu kwachitika pakupanga makristalo amodzi a SiC ku China. M'dziko muno, makristalo amodzi a 4H-SiC okhala ndi semi-insulating 100 mm apangidwa bwino, ndipo makristalo amodzi a 4H-SiC ndi 6H-SiC amtundu wa n tsopano akhoza kupangidwa m'magulu. Makampani monga TankeBlue ndi TYST apanga kale makristalo amodzi a 150 mm SiC.

Ponena za ukadaulo wokonza ma wafer a SiC, mabungwe am'nyumba ayamba kale kufufuza momwe zinthu zilili komanso njira zodulira makristalo, kupukutira, ndi kupukuta. Amatha kupanga zitsanzo zomwe zimakwaniritsa zofunikira popanga zipangizo. Komabe, poyerekeza ndi miyezo yapadziko lonse lapansi, ubwino wokonza pamwamba pa ma wafer a m'nyumba umatsalira kwambiri. Pali mavuto angapo:

Malingaliro apadziko lonse a SiC ndi ukadaulo wokonza zinthu zimatetezedwa kwambiri ndipo sizikupezeka mosavuta.

Pali kusowa kwa kafukufuku wa chiphunzitso ndi chithandizo cha kukonza ndi kukonza njira.

Mtengo wogulira zida ndi zida zakunja ndi wokwera.

Kafukufuku wa m'dziko muno pa kapangidwe ka zida, kulondola kwa ntchito, ndi zipangizo zikusonyezabe mipata yayikulu poyerekeza ndi mayiko ena.

Pakadali pano, zida zambiri zolondola kwambiri zomwe zimagwiritsidwa ntchito ku China zimatumizidwa kunja. Zipangizo zoyesera ndi njira zoyesera zimafunikanso kukonzedwanso.

Ndi chitukuko chopitilira cha ma semiconductors a m'badwo wachitatu, kukula kwa ma substrates a SiC single crystal kukuwonjezeka pang'onopang'ono, pamodzi ndi zofunikira zapamwamba pakupanga zinthu pamwamba. Ukadaulo wokonza ma wafer wakhala chimodzi mwa zinthu zovuta kwambiri paukadaulo pambuyo pa kukula kwa ma crystals a SiC single.

Pofuna kuthana ndi mavuto omwe alipo pakupanga zinthu, ndikofunikira kuphunzira njira zomwe zimagwiritsidwa ntchito podula, kupera, ndi kupukuta, komanso kufufuza njira zoyenera zopangira zinthu za SiC wafer. Nthawi yomweyo, ndikofunikira kuphunzira kuchokera ku ukadaulo wapamwamba wapadziko lonse lapansi wopangira zinthu ndikugwiritsa ntchito njira zamakono zopangira zinthu ndi zida zamakono kuti apange zinthu zapamwamba kwambiri.

Pamene kukula kwa wafer kumawonjezeka, vuto la kukula ndi kukonza makristalo limakulanso. Komabe, luso lopanga zida zotsika limakula kwambiri, ndipo mtengo wa unit umachepa. Pakadali pano, ogulitsa ma wafer akuluakulu a SiC padziko lonse lapansi amapereka zinthu kuyambira mainchesi 4 mpaka mainchesi 6 m'mimba mwake. Makampani otsogola monga Cree ndi II-VI ayamba kale kukonzekera kupanga mizere yopanga ma wafer a SiC mainchesi 8.