Wafers na Silicon da Gilashi: Menene Muke Tsaftacewa A Hakika? Daga Mahimman Abubuwan Aiki zuwa Maganin Tsaftacewa Mai Tsarin Aiki

Duk da cewa wafers ɗin silicon da gilashi suna da burin "tsabtace" juna, ƙalubalen da yanayin gazawar da suke fuskanta yayin tsaftacewa sun bambanta sosai. Wannan rashin jituwa ya samo asali ne daga halayen kayan da ke cikin su da buƙatun ƙayyadaddun bayanai na silicon da gilashi, da kuma "falsafar" tsaftacewa da aka yi amfani da su a ƙarshe.

Da farko, bari mu fayyace: Menene ainihin abin da muke tsaftacewa? Waɗanne gurɓatattun abubuwa ne ke tattare da su?

Ana iya rarraba gurɓatattun abubuwa zuwa rukuni huɗu:

1. Gurɓatattun ƙwayoyin cuta

   • Ƙura, ƙwayoyin ƙarfe, ƙwayoyin halitta, ƙwayoyin da ke lalata (daga tsarin CMP), da sauransu.

   • Waɗannan gurɓatattun abubuwa na iya haifar da lahani a tsarin, kamar gajerun wando ko kuma buɗewar da'ira.

2. Gurɓatattun Halittu

   • Ya haɗa da ragowar masu hana hasken rana, ƙarin sinadarai na resin, man fatar ɗan adam, ragowar sinadarai masu narkewa, da sauransu.

   • Gurɓatattun abubuwa na halitta na iya samar da abin rufe fuska wanda ke hana etching ko dasa ion da rage mannewar wasu siririn fim.

3. Gurɓatattun ion na ƙarfe

   • Baƙin ƙarfe, jan ƙarfe, sodium, potassium, calcium, da sauransu, waɗanda galibi suna fitowa ne daga kayan aiki, sinadarai, da hulɗa da mutane.

   • A cikin semiconductors, ions na ƙarfe gurɓatattun abubuwa ne masu "mummunan" waɗanda ke haifar da matakan makamashi a cikin haramtaccen madauri, wanda ke ƙara yawan kwararar ruwa, yana rage tsawon rayuwar mai ɗaukar kaya, kuma yana lalata halayen lantarki sosai. A cikin gilashi, suna iya shafar inganci da mannewar siririn fim ɗin da ke gaba.

4. Layer na Oxide na asali

   • Ga wafers na silicon: Siraran silicon dioxide (Native Oxide) yana samuwa a zahiri a saman iska. Kauri da daidaiton wannan Layer na oxide yana da wahalar sarrafawa, kuma dole ne a cire shi gaba ɗaya yayin ƙera manyan tsare-tsare kamar ƙofofin gate.

   • Ga gilashin wafers: Gilashin kanta tsarin silica ne, don haka babu wata matsala ta "cire wani yanki na oxide na asali." Duk da haka, ana iya gyara saman saboda gurɓatawa, kuma ana buƙatar cire wannan Layer.

I. Manyan Manufofi: Bambancin Aiki Tsakanin Wutar Lantarki da Cikakkiyar Jiki

• Wafers na Silicon

  • Babban burin tsaftacewa shine tabbatar da aikin lantarki. Bayanai yawanci sun haɗa da ƙididdige ƙwayoyin cuta da girma dabam-dabam (misali, dole ne a cire ƙwayoyin cuta ≥0.1μm yadda ya kamata), yawan ion na ƙarfe (misali, Fe, dole ne a sarrafa Cu zuwa ≤10¹⁰ atoms/cm² ko ƙasa da haka), da matakan ragowar halitta. Ko da gurɓataccen abu na iya haifar da gajerun hanyoyin da'ira, kwararar ruwa, ko gazawar ingancin oxide na ƙofar.

• Wafers na Gilashi

  • A matsayin substrates, manyan buƙatun sune kamala ta zahiri da kwanciyar hankali na sinadarai. Takamaiman bayanai sun fi mayar da hankali kan fannoni na matakin macro kamar rashin karce, tabo marasa cirewa, da kuma kula da ƙaiƙayin saman asali da yanayinsa. Manufar tsaftacewa ita ce tabbatar da tsaftar gani da kuma mannewa mai kyau ga ayyuka masu zuwa kamar shafa.

II. Yanayin Kayan Aiki: Babban Bambanci Tsakanin Lu'ulu'u da Amorphous

• Silicon

  • Silicon abu ne mai lu'ulu'u, kuma saman sa yana tsiro da wani Layer na oxide wanda ba shi da tsari irin na silicon dioxide (SiO₂). Wannan Layer na oxide yana haifar da haɗari ga aikin lantarki kuma dole ne a cire shi gaba ɗaya kuma a daidaita shi.

• Gilashi

  • Gilashi wata hanyar sadarwa ce ta silica mara tsari. Babban kayansa yayi kama da layin silicon oxide na silicon, wanda ke nufin hydrofluoric acid (HF) zai iya goge shi da sauri kuma yana iya fuskantar lalacewar alkali mai ƙarfi, wanda ke haifar da ƙaruwar ƙaiƙayi ko nakasa. Wannan babban bambanci yana nuna cewa tsaftace silicon wafer na iya jure wa haske da tsaftacewa don cire gurɓatattun abubuwa, yayin da tsaftace gilashin wafer dole ne a yi shi da taka tsantsan don guje wa lalata kayan tushe.

III. Kwatanta Maganin Tsaftacewa

Dangane da manufofin da aka ambata da halayen kayan da aka ambata, hanyoyin tsaftacewa don wafers na silicon da gilashi sun bambanta:

• Tsarin Tsaftace Gilashin Wafer

  • A halin yanzu, yawancin masana'antun sarrafa gilashi suna amfani da hanyoyin tsaftacewa bisa ga halayen kayan gilashi, suna dogara ne akan ƙarancin sinadaran tsaftacewa na alkaline.

  • Halayen Maganin Tsaftacewa:Waɗannan sinadarai na musamman na tsaftacewa galibi suna da ƙarancin alkaline, tare da pH kusan 8-9. Yawanci suna ɗauke da surfactants (misali, alkyl polyoxyethylene ether), sinadaran chelating na ƙarfe (misali, HEDP), da kayan aikin tsaftacewa na halitta, waɗanda aka tsara don emulsions da lalata gurɓatattun abubuwa na halitta kamar mai da yatsa, yayin da suke da ɗan lalata ga matrix ɗin gilashi.

  • Gudun Tsarin Aiki:Tsarin tsaftacewa na yau da kullun ya ƙunshi amfani da takamaiman yawan sinadarai masu ƙarfi na tsaftacewar alkaline a yanayin zafi daga zafin ɗaki zuwa 60°C, tare da tsaftacewar ultrasonic. Bayan tsaftacewa, wafers ɗin suna yin matakai da yawa na wankewa da ruwa mai tsabta da bushewa mai laushi (misali, ɗagawa a hankali ko bushewar tururin IPA). Wannan tsari ya cika buƙatun wafer ɗin gilashi don tsabtar gani da tsabta gabaɗaya.

• Tsarin Tsaftace Wafer na Silicon

  • Don sarrafa semiconductor, wafers na silicon yawanci suna yin tsaftacewar RCA ta yau da kullun, wanda hanya ce mai matuƙar tasiri ta tsaftacewa wadda ke iya magance duk wani nau'in gurɓatawa cikin tsari, ta hanyar tabbatar da cewa an cika buƙatun aikin lantarki na na'urorin semiconductor.

IV. Lokacin da Gilashi Ya Cika Manyan Ka'idojin "Tsabta"

Idan ana amfani da wafers na gilashi a aikace-aikace da ke buƙatar ƙididdige ƙwayoyin cuta masu tsauri da matakan ion na ƙarfe (misali, a matsayin substrates a cikin hanyoyin semiconductor ko don kyakkyawan saman ɓoye fim), tsarin tsaftacewa na ciki bazai isa ba. A wannan yanayin, ana iya amfani da ƙa'idodin tsaftacewa na semiconductor, wanda ke gabatar da dabarun tsaftacewa na RCA da aka gyara.

Babban manufar wannan dabarar ita ce a rage da kuma inganta sigogin tsarin RCA na yau da kullun don dacewa da yanayin da ke da alaƙa da gilashi:

• Cire Gurɓataccen Halitta:Ana iya amfani da ruwan SPM ko ruwan ozone mai laushi don lalata gurɓatattun abubuwa ta hanyar iskar shaka mai ƙarfi.

• Cire ƙwayoyin cuta:Ana amfani da maganin SC1 mai narkewa sosai a ƙananan yanayin zafi da kuma gajerun lokutan magani don amfani da tasirinsa na lantarki da ƙananan etching don cire ƙwayoyin cuta, yayin da ake rage tsatsa a gilashin.

• Cirewar ion na ƙarfe:Ana amfani da maganin SC2 mai narkewa ko kuma maganin hydrochloric acid/dilute nitric acid mai sauƙi don cire gurɓatattun ƙarfe ta hanyar chelation.

• Haramcin da Ya Kamata a Yi:Dole ne a guji DHF (di-ammonium fluoride) gaba ɗaya don hana tsatsa na gilashin.

A cikin dukkan tsarin da aka gyara, haɗa fasahar megasonic yana ƙara inganta aikin cire ƙwayoyin nano sosai kuma yana da laushi a saman.

Kammalawa

Tsarin tsaftacewa na wafers na silicon da gilashi sakamako ne da ba makawa na injiniyan baya bisa ga buƙatun aikace-aikacen su na ƙarshe, halayen kayan aiki, da halayen jiki da sinadarai. Tsaftace wafer na silicon yana neman "tsabtace matakin atomic" don aikin lantarki, yayin da tsaftace wafers na gilashi ke mai da hankali kan cimma saman jiki "cikakke, mara lalacewa". Yayin da ake ƙara amfani da wafers na gilashi a aikace-aikacen semiconductor, hanyoyin tsaftacewarsu ba makawa za su ci gaba fiye da tsabtace alkaline na gargajiya, suna haɓaka ƙarin mafita masu kyau, na musamman kamar tsarin RCA da aka gyara don cika manyan ƙa'idodi na tsabta.