Amfani da Karfe a Masana'antar Na'urorin Semiconductor
Na'urorin Semiconductor—kamar transistors, diodes, firikwensin, da'irori masu haɗawa (ICs), da masu sarrafawa—su ne ginshiƙin fasahar zamani. Bayan babban aikinsu da ƙananan girmansu akwai wani tsari mai sarkakiya, daidaitacce, kuma mai dogaro da kayan aiki. Wata ƙungiya ta kayan da ba za a iya maye gurbinsu ba ita ce ƙarfe. Ana amfani da ƙarfe ba kawai azaman "wayoyi" masu sarrafa wutar lantarki ba, har ma azaman hulɗar lantarki, shingayen yaɗuwa, abubuwan da ke haɗa abubuwa tsakanin abubuwan haɗin gwiwa, da kayan aiki a cikin lithography da tsarin marufi. Wannan labarin ya tattauna yadda ake amfani da ƙarfe a cikin kera na'urorin semiconductor, nau'ikan ƙarfe da aka saba amfani da su, da ƙalubale da alkiblar ci gaban su.
1. Matsayin karafa a cikin na'urorin semiconductor
Gabaɗaya, ƙarfe a cikin na'urorin semiconductor suna da manyan ayyuka da yawa:
1. Haɗi (wayoyi): Haɗa transistors da sauran abubuwan da ke cikin guntu ta hanyar hanyoyin ƙarfe masu yawa da yawa (haɗin kai mai matakai da yawa).
2. Lambobin sadarwa na Ohmic da kuma lambobin sadarwa na Schottky: Samar da hanyar sadarwa ta lantarki tsakanin ƙarfe da semiconductor. Lambobin sadarwa na Ohmic suna ba da damar kwararar wutar lantarki a duka kwatancen tare da ƙarancin juriya, yayin da lambobin sadarwa na Schottky ke samar da diode mai halaye masu gyara.
3. Tsarin shinge da kuma mannewa: Yana hana yaɗuwar ƙwayoyin ƙarfe zuwa cikin kayan semiconductor ko dielectric, kuma yana taimaka wa ƙarfen ya manne sosai a kan layin da ke ƙasa.
4. Wutar lantarki ta ƙofar lantarki a kan transistor: A wasu fasahohi, ana amfani da ƙarfe don samar da wutar lantarki ta ƙofar lantarki a kan MOSFET don ingantaccen sarrafa tashoshi da ƙarancin juriya.
5. Kayan aiki a cikin tsarin ƙera: Ana amfani da ƙarfe da mahaɗan ƙarfe a matsayin abin rufe fuska mai tauri, yadudduka masu haske, ko abubuwan sinadarai don adanawa da ƙera abubuwa.
6. Marufi da haɗin guntu: Ana amfani da solder, haɗin waya, bumping, da kuma ƙarfe daban-daban don haɗa guntu da allon da'ira da kuma kare na'urar daga muhalli.
A wata ma'anar, aikin kwakwalwan zamani ba wai kawai ta hanyar silicon ko wasu kayan semiconductor ba ne, har ma ta hanyar yadda aka zaɓi ƙarfe da haɗa su.
2. Karfe don haɗakarwa: daga aluminum zuwa jan ƙarfe da cobalt
A farkon ƙarni na ICs, aluminum (Al) shine babban zaɓi na haɗin gwiwa saboda yana da sauƙin ajiyewa, mai rahusa, kuma ya dace da tsarin ƙera na lokacin. Duk da haka, yayin da yawan transistor ke ƙaruwa kuma buƙatun yanzu suka ƙaru, matsaloli kamar ƙaura ta hanyar lantarki - motsi na ƙwayoyin ƙarfe saboda yawan kwararar lantarki - sun haifar da karyewar hanya da raguwar aminci.
Daga nan masana'antar ta koma jan ƙarfe (Cu) saboda tana da ƙarancin juriya fiye da aluminum, tana rage asarar wutar lantarki da kuma ƙara saurin sigina. Duk da haka, jan ƙarfe yana gabatar da ƙalubale: Cu yana yaɗuwa cikin sauƙi zuwa dielectrics (misali, SiO₂ ko dielectrics mai ƙarancin k) kuma yana iya lalata halayen lantarki. Saboda haka, kusan koyaushe ana amfani da Cu tare da wani shinge kamar tantalum (Ta) ko tantalum nitride (TaN).
A cikin ƙananan fasahohi (masu ci gaba), haɗin haɗin gwiwa yana raguwa, yana ƙara juriya, kuma tasirin iyaka (watsawar saman) ya zama mafi rinjaye. Ga wasu yadudduka, amfani da cobalt (Co) ko ruthenium (Ru) a matsayin madadin/ƙari ga Cu ya fara bayyana saboda yana iya samar da ingantaccen aiki a ƙananan girma kuma yana rage buƙatar shinge mai kauri.
3. Haɗin ƙarfe-semiconductor: ohmic da Schottky
Hulɗar da ke tsakanin ƙarfe da semiconductor tana ɗaya daga cikin muhimman fannoni. Idan hulɗar ta yi ƙarfi sosai, transistor ɗin zai yi zafi da sauri kuma ya rasa aiki. A cikin na'urorin CMOS na zamani, an tsara hanyoyin haɗi/magudanar ruwa da toshewar haɗi don samun mafi ƙarancin juriya.
Wasu karafa da mahaɗan da aka saba amfani da su don hulɗa sun haɗa da:
– Titanium (Ti): galibi ana amfani da shi azaman manne da kuma mai amsawa don samar da silicide.
– Nickel (Ni) da cobalt (Co): sun zama ruwan dare a cikin hanyoyin silication (misali NiSi, CoSi₂) don rage juriyar hulɗa a cikin silicon.
– Tungsten (W): ana amfani da shi sosai a matsayin "toshe" don cike ramukan hulɗa (ta hanyar cikewa/ta hanyar cikawa) saboda yana da karko kuma ya dace da ajiyar CVD (tashin tururi na sinadarai).
– Platinum (Pt) ko palladium (Pd): ana iya amfani da shi don ƙirƙirar hulɗar Schottky ko don wasu aikace-aikacen da ke buƙatar kwanciyar hankali mai yawa na sinadarai.
A cikin na'urorin da aka yi da semiconductors banda silicon—kamar GaN (gallium nitride) ko SiC (silicon carbide)—zaɓin ƙarfe mai taɓawa yana ƙara zama mahimmanci saboda bambance-bambance a cikin tsarin ma'aunin makamashi, buƙatun zafin jiki mai yawa, da kuma yanayin aiki mai tsauri (misali, na'urorin lantarki masu amfani da wutar lantarki).
4. Layin shinge, layin rufi, da kuma layin mannewa
Saboda ƙananan ƙwayoyin zamani suna da yawa, ƙwayoyin ƙarfe na iya yaɗuwa kuma su haifar da zubewa, gajerun abubuwa, ko canje-canje a cikin sigogin transistor. Saboda haka, ana amfani da siraran yadudduka, waɗanda ke aiki da waɗannan ayyuka:
– Katangar Yaɗuwa: tana hana yaɗuwar Cu ko wasu ƙarfe.
– Layin layi: yana taimakawa wajen cike kunkuntar siffofi (tashar/ta hanyar) daidai gwargwado.
- Layer ɗin mannewa: yana ƙara mannewa.
Kayan da aka fi amfani da su sun haɗa da Ta/TaN, Ti/TiN, W, kuma a cikin binciken da aka yi kwanan nan, shingen da aka yi da Ru, Mn, ko yadudduka masu siriri sosai bisa ga kayan 2D a matsayin shingen yaɗuwa. Yayin da ƙusoshi ke ci gaba, ƙalubalen shine a sanya shingen ya zama siriri gwargwadon iko yayin da yake ci gaba da tasiri, kamar shingen da ya yi kauri sosai yana "cinye" sararin hanya kuma yana ƙara juriya.
5. Tsarin ƙarfe a cikin transistor: ƙofar ƙarfe da babban-k
A cikin transistors na zamani na MOSFET, musamman tun bayan ƙaddamar da ƙofofin high-k/metal, ƙarfe ya sake taka muhimmiyar rawa a cikin tsarin ƙofa. A da, ana amfani da ƙofofin polysilicon sau da yawa, amma suna fuskantar matsaloli kamar tasirin raguwar aiki da kuma dacewa da dielectrics masu high-k. Tare da ƙofofin ƙarfe, ana inganta ikon sarrafa wutar lantarki kuma ana iya danne zubewa.
Kayan da aka yi amfani da su sun bambanta, kamar titanium nitride (TiN), tantalum nitride, ko haɗin ƙarfe da aka ƙera don cimma aikin aiki daidai (don ƙarfin wutar lantarki ya cika ƙirar). A nan, ƙarfe ba wai kawai jagora ba ne; halayen lantarki na saman sa suna ƙayyade halayen transistor.
6. Amfani da ƙarfe wajen adanawa da tsara tsari
Kera guntu ya ƙunshi ajiye ƙananan yadudduka na ƙarfe ta hanyoyi daban-daban, waɗanda suka haɗa da:
– PVD (Turin da ke cikin jiki): kamar fitar da ruwa, wanda aka saba gani a Al, Ti, Ta, da sauransu.
– CVD (Sinadarin Tururi Mai Tsami): sau da yawa ana amfani da shi don toshewar W (tungsten) da wasu layukan ƙarfe.
– ALD (Atomic Layer Deposition): yana da matuƙar muhimmanci ga yadudduka masu siriri da tsari akan tsarin 3D, misali shinge/layi, ƙofofin ƙarfe, da wasu kayan hulɗa.
Bayan an gama tattarawa, dole ne a yi wa ƙarfen tsari ta amfani da lithography da etching ko kuma tsarin damascene (musamman ga Cu), wanda ya haɗa da ƙirƙirar ramuka a cikin dielectric, cika su da ƙarfe, sannan a goge su ta amfani da Chemical Mechanical Planarization (CMP). Wannan tsari yana buƙatar slurry da sunadarai masu dacewa don ƙirƙirar saman da ba shi da lahani ba tare da lalata layukan da ke ƙasa ba.
7. Karfe a kan marufi: solder, bump, da waya bond
Da zarar an gama wafer ɗin, sai a yanka guntun (a yanka shi) sannan a naɗe shi. A wannan matakin, ƙarfe ma yana da rinjaye:
– Haɗa waya yana amfani da wayar zinare (Au), aluminum (Al), ko jan ƙarfe (Cu).
– Bumping da flip-chip suna amfani da ginshiƙai/bumps da solder na ƙarfe don haɗin sauri da manyan lambobi.
– Ana amfani da solders na zamani da tin (Sn) da ƙarfe (misali Sn-Ag-Cu) don maye gurbin solder na gubar (Pb) saboda dalilai na muhalli.
Manyan marufi kamar chiplets, haɗin 2.5D/3D, da TSV (ta hanyar silicon via) suna ƙara buƙatar kayan ƙarfe masu inganci, yayin da yawan haɗin kai da watsawar zafi ke ƙaruwa.
8. Manyan ƙalubale: ƙaura ta hanyar lantarki, tsatsa, da juriya a sikelin nano
Yayin da girman ya ƙanƙanta, amfani da ƙarfe yana fuskantar ƙalubale masu tsanani, ciki har da:
– Fitowar lantarki: hanyoyin ƙarfe na iya lalacewa ta hanyar kwararar ruwa mai yawa a cikin ƙananan sassan giciye.
– Ƙara ƙarfin juriya: a sikelin nano, electrons suna karo akai-akai da iyakokin hatsi da saman, suna ƙara juriya.
– Daidaitawar tsatsa da sinadarai: musamman a matakan samarwa da suka shafi sinadarai da yawa da yanayin zafi mai yawa.
– Iyakokin shinge: dole ne shingen ya zama siriri kuma har yanzu yana tsayayya da yaɗuwa, wanda hakan yana da wahala a zahiri.
Saboda haka, bincike kan kayan ƙarfe na semiconductors yana ci gaba da bunƙasa, gami da binciken Co, Ru, Mo, da kuma sabbin hanyoyin haɗin gwiwa na kayan aiki da dabarun adana atomic.
9. Umarnin amfani da ƙarfe a nan gaba
Abubuwan da ke faruwa a nan gaba a masana'antar semiconductor suna haifar da amfani da ƙarin ƙarfe masu "ingantacce" a matakin atomic. Ci gaba da tsare-tsare da gine-ginen 3D (FinFET, GAA nanosheet, da sauransu) suna buƙatar yadudduka masu kama da juna, siriri sosai tare da hanyoyin sadarwa masu tsabta. Bugu da ƙari, buƙatar ingantaccen amfani da makamashi da sauri shi ma ya sa zaɓin ƙarfe don haɗin gwiwa da hulɗa ya zama babban abin da ke haifar da hakan.
A ɓangaren marufi, buƙatun babban bandwidth da haɗin kai daban-daban suna haifar da ƙirƙira a cikin abubuwan haɗin solder, bump, da ƙarfe. Karfe ba wai kawai wani ɓangare ne mai tallafawa ba, har ma wani muhimmin ɓangare ne na ƙirar tsarin, aiki, da aminci.
Kammalawa
Karfe yana taka muhimmiyar rawa wajen ƙera na'urorin semiconductor: a matsayin haɗin gwiwa, hulɗa, shinge, ƙofofin ƙarfe, da kuma tushen marufi. Ana ƙayyade zaɓin ƙarfe ba kawai ta hanyar amfani da wutar lantarki ba, har ma ta hanyar yaɗuwa, mannewa, kwanciyar hankali na zafi, dacewa da tsari, da kuma aminci na dogon lokaci. Yayin da ƙaramar haɓakawa da sarkakiya ke ƙaruwa, ƙalubale kamar ƙaura ta lantarki da juriya ta nanoscale suna tilasta masana'antar haɓaka sabbin kayayyaki da matakai. Saboda haka, fahimtar amfani da ƙarfe a cikin semiconductor yana da mahimmanci ba kawai ga kayan aiki da injiniyoyin sarrafawa ba, har ma ga duk wanda ke neman fahimtar yadda fasahar guntu ta zamani za ta ci gaba da bunƙasa.
