Kugwiritsa Ntchito Zitsulo Popanga Zipangizo Za Semiconductor
Zipangizo za semiconductor—monga ma transistors, ma diode, masensa, ma integrated circuits (ICs), ndi ma processor—ndizo maziko a ukadaulo wamakono. Kumbuyo kwa magwiridwe antchito awo apamwamba komanso kukula kochepa kuli njira yopangira zinthu yovuta, yolondola, komanso yodalira kwambiri zinthu. Gulu limodzi la zipangizo zomwe ntchito yake siisintha ndi chitsulo. Zitsulo sizimagwiritsidwa ntchito ngati "mawaya" oyendetsera magetsi okha komanso ngati kulumikizana kwa magetsi, zotchinga zofalitsa, zinthu zolumikizirana pakati pa zigawo, ndi zinthu zogwirira ntchito mu lithography ndi njira zopakira. Nkhaniyi ikufotokoza momwe zitsulo zimagwiritsidwira ntchito popanga zida za semiconductor, mitundu ya zitsulo zomwe zimagwiritsidwa ntchito nthawi zambiri, komanso zovuta ndi malangizo a chitukuko chawo.
1. Udindo wa zitsulo mu zipangizo za semiconductor
Kawirikawiri, zitsulo zomwe zili mu zipangizo za semiconductor zimakhala ndi ntchito zingapo zazikulu:
1. Kulumikizana (kulumikiza mawaya): Kulumikiza ma transistors ndi zigawo zina mu chip kudzera m'njira zachitsulo zokhuthala kwambiri komanso zokhala ndi zigawo zambiri (kulumikizana kwa zigawo zambiri).
2. Ma contact a Ohmic ndi ma contact a Schottky: Amapanga kulumikizana kwamagetsi pakati pa chitsulo ndi semiconductor. Ma contact a Ohmic amalola kuti magetsi aziyenda mbali zonse ziwiri popanda kukana kwambiri, pomwe ma contact a Schottky amapanga diode yokhala ndi mawonekedwe okonzanso.
3. Chotchinga ndi chomatira: Chimaletsa kufalikira kwa maatomu achitsulo mu semiconductor kapena dielectric, ndipo chimathandiza chitsulocho kumamatira mwamphamvu ku gawo lomwe lili pansipa.
4. Electrode ya chipata pa transistor: Mu ukadaulo wina, chitsulo chimagwiritsidwa ntchito kupanga electrode ya chipata pa MOSFET kuti chiwongolere bwino njira ndi kuchepetsa kukana.
5. Zipangizo zomwe zimagwiritsidwa ntchito popanga zinthu: Zitsulo ndi zinthu zina zachitsulo zimagwiritsidwa ntchito ngati zophimba nkhope zolimba, zigawo zowunikira, kapena zinthu zina za mankhwala zoyikamo ndi kupukuta.
6. Kuyika ndi kulumikiza ma chip: Solder, waya womangirira, bumping, ndi zitsulo zosiyanasiyana zimagwiritsidwa ntchito kulumikiza chip ku bolodi la circuit ndikuteteza chipangizocho ku chilengedwe.
Mwa kuyankhula kwina, magwiridwe antchito a tchipisi zamakono samangodalira silicon kapena zinthu zina za semiconductor, komanso momwe zitsulo zimasankhidwira ndikuphatikizidwa.
2. Zitsulo zolumikizirana: kuyambira aluminiyamu mpaka mkuwa ndi cobalt
M'mibadwo yoyambirira ya ma IC, aluminiyamu (Al) inali chisankho chachikulu cha maulumikizidwe chifukwa inali yosavuta kuyika, yotsika mtengo, komanso yogwirizana ndi njira zopangira zinthu panthawiyo. Komabe, pamene kuchuluka kwa ma transistor kunali kwakukulu komanso zofunikira pakali pano zikuwonjezeka, mavuto monga kusuntha kwa ma electromigration—kuyenda kwa maatomu achitsulo chifukwa cha kuyenda kwa ma electron ambiri—zinayambitsa kusweka kwa njira ndi kuchepa kwa kudalirika.
Kenako makampaniwa anayamba kugwiritsa ntchito mkuwa (Cu) chifukwa uli ndi mphamvu yocheperako poyerekeza ndi aluminiyamu, zomwe zimachepetsa kutayika kwa mphamvu ndikuwonjezera liwiro la chizindikiro. Komabe, mkuwa umabweretsa vuto: Cu imafalikira mosavuta mu ma dielectric (monga SiO₂ kapena ma dielectric otsika-k) ndipo imatha kuwononga mphamvu zamagetsi. Chifukwa chake, Cu nthawi zambiri imagwiritsidwa ntchito ndi chotchinga monga tantalum (Ta) kapena tantalum nitride (TaN).
Mu ukadaulo wocheperako (ma node apamwamba), gawo lolumikizana limachepa, kukana kumawonjezeka kwambiri, ndipo zotsatira zake (kufalikira pamwamba) zimakhala zofala kwambiri. Pa zigawo zina, kugwiritsa ntchito cobalt (Co) kapena ruthenium (Ru) ngati njira ina/yowonjezera Cu kwayamba kuonekera chifukwa kumatha kupereka magwiridwe antchito okhazikika pamlingo wocheperako kwambiri ndikuchepetsa kufunikira kwa zotchinga zokhuthala.
3. Zolumikizirana ndi zitsulo ndi semiconductor: ohmic ndi Schottky
Kulumikizana pakati pa chitsulo ndi semiconductor ndi chimodzi mwa zinthu zofunika kwambiri. Ngati kukhudzanako kuli kolimba kwambiri, transistor imatentha kwambiri ndipo imataya mphamvu. Mu zipangizo zamakono za CMOS, ma source/drain contacts ndi ma contact plugs amapangidwa kuti akhale ndi kukana kochepa kwambiri.
Zitsulo ndi mankhwala ena omwe amagwiritsidwa ntchito kwambiri polumikizana ndi zinthu ndi awa:
– Titaniyamu (Ti): nthawi zambiri imagwiritsidwa ntchito ngati guluu komanso ngati gawo lothandizira kupanga mankhwala ophera tizilombo toyambitsa matenda.
– Nickel (Ni) ndi cobalt (Co): zimapezeka kwambiri mu njira zosinthira silicide (monga NiSi, CoSi₂) kuti zichepetse kukana kwa silicon.
– Tungsten (W): imagwiritsidwa ntchito kwambiri ngati "pulagi" yodzaza mabowo olumikizana (kukhudzana/kudzera mu kudzaza) chifukwa ndi yokhazikika komanso yoyenera kuyika CVD (chemical vapor deposition).
– Platinum (Pt) kapena palladium (Pd): ingagwiritsidwe ntchito kupanga ma contact a Schottky kapena pa ntchito zina zomwe zimafuna kukhazikika kwa mankhwala.
Mu zipangizo zopangidwa kuchokera ku ma semiconductors ena osati silicon—monga GaN (gallium nitride) kapena SiC (silicon carbide)—kusankha chitsulo cholumikizirana kumakhala kofunika kwambiri chifukwa cha kusiyana kwa kapangidwe ka mphamvu, zofunikira kutentha kwambiri, komanso malo ogwirira ntchito kwambiri (monga magetsi amagetsi).
4. Chotchinga, choyikapo, ndi chomatira
Popeza ma tchipisi amakono ndi ang'onoang'ono kwambiri, maatomu achitsulo amatha kufalikira ndikuyambitsa kutuluka kwa madzi, ma shorts, kapena kusintha kwa magawo a transistor. Chifukwa chake, magawo opyapyala amagwiritsidwa ntchito, omwe amagwira ntchito zotsatirazi:
– Cholepheretsa kufalikira: chimaletsa kufalikira kwa Cu kapena zitsulo zina.
– Liner: imathandiza kudzaza zinthu zopapatiza (ngalande/njira) mofanana.
– Kumatirira: kumawonjezera kumatira.
Zipangizo zodziwika bwino zikuphatikizapo Ta/TaN, Ti/TiN, W, ndipo kafukufuku waposachedwapa, zotchinga zochokera ku Ru, Mn, kapena zigawo zoonda kwambiri zochokera ku zipangizo za 2D ngati zotchinga zofalitsa. Pamene mfundo zikupitirira, vuto ndi kupanga chotchingacho kukhala chocheperako momwe zingathere pamene chikugwirabe ntchito, chifukwa chotchinga chomwe chili chokhuthala kwambiri "chimadya" malo olowera ndikuwonjezera kukana.
5. Chitsulo chopangidwa ndi transistor: chipata chachitsulo ndi high-k
Mu ma transistors amakono a MOSFET, makamaka kuyambira pomwe zidayamba kugwiritsa ntchito zipata za high-k/metal, chitsulo chakhalanso ndi gawo lalikulu pa kapangidwe ka zipata. Kale, zipata za polysilicon zinkagwiritsidwa ntchito nthawi zambiri, koma zinkakumana ndi mavuto monga kuchepa kwa mphamvu ndi kugwirizana ndi ma dielectric a high-k. Ndi zipata zachitsulo, kulamulira kwa electrostatic kumawonjezeka ndipo kutuluka kwa madzi kumatha kuchepetsedwa.
Zipangizo zomwe zimagwiritsidwa ntchito zimasiyana, monga titanium nitride (TiN), tantalum nitride, kapena kuphatikiza zitsulo zopangidwa kuti zigwire ntchito moyenera (kotero kuti mphamvu yamagetsi yolowera ikwaniritse kapangidwe kake). Apa, chitsulocho sichimangokhala kondakitala; mawonekedwe ake amagetsi pamwamba pake ndi omwe amatsimikiza momwe transistor imagwirira ntchito.
6. Kugwiritsa ntchito chitsulo poika ndi kupanga mapangidwe
Kupanga ma chip kumaphatikizapo kuyika zitsulo zoonda pogwiritsa ntchito njira zosiyanasiyana, kuphatikizapo:
– PVD (Kutulutsa nthunzi m'thupi): monga kutulutsa madzi, komwe kumachitika kawirikawiri kwa Al, Ti, Ta, ndi ena.
– CVD (Chemical Npor Deposition): nthawi zambiri imagwiritsidwa ntchito pa mapulagi a W (tungsten) ndi zigawo zina zachitsulo.
– ALD (Atomic Layer Deposition): Chofunika kwambiri pa zigawo zoonda kwambiri komanso zooneka ngati mawonekedwe pa nyumba za 3D, mwachitsanzo zotchinga/zotchingira, zipata zachitsulo, ndi zipangizo zina zolumikizirana.
Pambuyo poika chitsulocho, chiyenera kupangidwa pogwiritsa ntchito lithography ndi etching kapena njira ya damascene (makamaka ya Cu), yomwe imaphatikizapo kupanga ngalande mu dielectric, kuzidzaza ndi chitsulo, kenako kuzipukuta pogwiritsa ntchito Chemical Mechanical Planarization (CMP). Njirayi imafuna slurry ndi chemistry yoyenera kuti ipange malo athyathyathya popanda kuwononga zigawo zapansi.
7. Chitsulo pa phukusi: chosungunula, bump, ndi waya womangira
Akamaliza kupukuta chigambacho, chimadulidwa (kudulidwa) ndikupakidwa. Pa siteji iyi, chitsulo chimakhala chofala kwambiri:
– Kulumikiza waya kumagwiritsa ntchito waya wagolide (Au), aluminiyamu (Al), kapena mkuwa (Cu).
- Kugunda ndi kutembenuza zipilala kumagwiritsa ntchito zipilala/zipilala zachitsulo ndi solder kuti zilumikize mwachangu komanso kuti zikhale ndi ma pin ambiri.
– Zosungunula zamakono nthawi zambiri zimakhala ndi tin (Sn) pogwiritsa ntchito alloys (monga Sn-Ag-Cu) kuti zilowe m'malo mwa lead (Pb) solder pazifukwa zachilengedwe.
Ma phukusi apamwamba monga ma chiplets, 2.5D/3D integration, ndi TSV (through-silicon via) akuwonjezera kufunikira kwa zipangizo zachitsulo zodalirika kwambiri, chifukwa kuchuluka kwa kulumikizana ndi kutentha kumawonjezeka.
8. Mavuto akuluakulu: kusamuka kwa magetsi, dzimbiri, ndi kukana kwa nanoscale
Pamene kukula kwake kukuchepa, kugwiritsa ntchito chitsulo kumakumana ndi mavuto aakulu, kuphatikizapo:
– Kusuntha kwa magetsi: njira zachitsulo zitha kuwonongeka ndi mafunde amphamvu m'magawo ang'onoang'ono.
– Kuwonjezeka kwa mphamvu yolimbana ndi zinthu: pa nanoscale, ma elekitironi amagundana pafupipafupi ndi malire a tirigu ndi malo ake, zomwe zimawonjezera mphamvu yolimbana ndi zinthuzo.
- Kugwirizana kwa dzimbiri ndi mankhwala: makamaka pakupanga komwe kumakhudza mankhwala ambiri komanso kutentha kwambiri.
– Zoletsa zotchinga: zotchinga ziyenera kukhala zopyapyala komanso zolimbana ndi kufalikira, zomwe zimakhala zovuta kwambiri.
Chifukwa chake, kafukufuku wokhudza zipangizo zachitsulo za ma semiconductors akupitilizabe kukula, kuphatikizapo kufufuza za Co, Ru, Mo, komanso njira zatsopano monga njira zina zolumikizirana ndi zinthu zina komanso njira zoyika atomiki.
9. Malangizo amtsogolo ogwiritsira ntchito zitsulo
Zochitika zamtsogolo mumakampani opanga ma semiconductor zikuyendetsa kugwiritsa ntchito zitsulo "zopangidwa mwaluso" kwambiri pamlingo wa atomiki. Ma node apamwamba ndi mapangidwe a 3D (FinFET, GAA nanosheet, ndi zina zotero) amafuna zigawo zachitsulo zofanana kwambiri, zopyapyala kwambiri zokhala ndi mawonekedwe oyera. Kuphatikiza apo, kufunikira kwa mphamvu yogwiritsira ntchito bwino komanso liwiro kumapangitsanso kusankha zitsulo zolumikizirana ndi zolumikizirana kukhala chinthu chofunikira.
Kumbali ya ma CD, zofunikira pa bandwidth yayikulu komanso kuphatikiza kosiyanasiyana zikuyendetsa luso la solder, bump, ndi metal interposer. Chitsulo sichimangothandiza kokha, komanso ndi gawo lofunikira pakupanga makina, magwiridwe antchito, komanso kudalirika.
Mapeto
Zitsulo zimagwira ntchito yofunika kwambiri popanga zipangizo za semiconductor: monga zolumikizirana, zolumikizirana, zotchinga, zipata zachitsulo, ndi msana wa phukusi. Kusankha zitsulo sikungodalira mphamvu yamagetsi yokha, komanso kufalikira, kumamatira, kukhazikika kwa kutentha, kugwirizana kwa njira, komanso kudalirika kwa nthawi yayitali. Pamene kusinthasintha pang'ono ndi zovuta zikuchulukirachulukira, zovuta monga kusuntha kwa magetsi ndi kukana kwa nanoscale zikukakamiza makampani kupanga zida ndi njira zatsopano. Chifukwa chake, kumvetsetsa kugwiritsa ntchito zitsulo mu semiconductor ndikofunikira osati kokha kwa zipangizo ndi mainjiniya a njira, komanso kwa aliyense amene akufuna kumvetsetsa momwe ukadaulo wamakono wa chip udzapitirire kusinthika.
