Inqubo yokwenza ama-RAM chips amaphilisi
I-RAM (Random Access Memory) ingenye yezingxenye ezibaluleke kakhulu kuthebhulethi. Ngaphandle kwe-RAM, ithebhulethi ayikwazi ukusebenzisa izinhlelo zokusebenza kahle, ukushintsha phakathi kwemisebenzi ngokushesha, noma ukugcina ukuphendula lapho izinqubo eziningi zisebenza ngesikhathi esisodwa. Naphezu kobukhulu bazo obuncane futhi ziboshwe ngokuqinile ngaphakathi kwedivayisi, ama-RAM chips angumphumela wenqubo yokukhiqiza eyinkimbinkimbi kakhulu, enembile kakhulu ehilela amakhulu ezinyathelo. Lesi sihloko sihlanganisa izinyathelo eziyinhloko enqubweni yokukhiqiza ama-RAM chips avame ukusetshenziswa kumathebhulethi—ngokuvamile uhlobo lwe-LPDDR (Low Power Double Data Rate), njengoba eklanyelwe ukuba asebenzise amandla kahle.
1. Umklamo wezakhiwo kanye nemininingwane yazo
Inqubo iqala isikhathi eside ngaphambi kokuba i-chip ebonakalayo ifaneleke. Amaqembu okuklama ezinkampanini ze-semiconductor anquma izidingo zemakethe yethebhulethi: amandla (isb., 4GB, 8GB, 12GB), i-bandwidth, ukusetshenziswa kwamandla, kanye nokuhambisana ne-system-on-chip (SoC). Kumathebhulethi anamuhla, i-RAM kumele ilinganisele ukusebenza kanye nokusebenza kahle kwebhethri. Ngakho-ke, amazinga afana ne-LPDDR4X noma i-LPDDR5/LPDDR5X avame ukusetshenziswa.
Esigabeni sokuklama, onjiniyela bathuthukisa nokwakheka kwamaseli enkumbulo, amabhange enkumbulo, izindlela zedatha (amabhasi edatha), kanye namasekethe asekelayo njenge-sense amplifiers, ama-row/column decoders, kanye nezindlela zokuvuselela. I-DRAM ihlukile ku-SRAM: I-DRAM igcina ama-bits isebenzisa ama-capacitor amancane okumele avuselelwe njalo, kuyilapho i-SRAM ishesha kodwa ibiza kakhulu futhi ithatha isikhala esiningi.
2. Ukwakhiwa nokuqinisekiswa kwesakhiwo
Uma ukwakheka sekuchaziwe, ukwakheka kuguqulwa kube ukwakheka okubonakalayo: imephu eningiliziwe yezindawo zama-transistors, ama-capacitor, ama-metal interconnect, kanye nezendlalelo ezizokwakhiwa ku-silicon wafer. Lesi sigaba sidinga isofthiwe ye-EDA (Electronic Design Automation) kanye nenqubo yokuqinisekisa eqinile ukuqinisekisa ukuthi ukwakheka kuyakhiqizwa futhi kusebenza njengoba kuhlosiwe.
Ukuqinisekiswa kuhlanganisa ukulingisa isikhathi, ukusetshenziswa kwamandla, ukuqina kokuguquguquka kwenqubo, kanye nokuhlolwa kwe-logic ukuze kugwenywe amaphutha abulalayo angabangela ukuthi lonke iqembu le-wafer lihluleke.
3. Ukukhiqizwa kwama-wafer e-silicon (ama-substrate)
Ama-RAM chips enziwa kuma-silicon wafers amsulwa kakhulu. I-silicon icutshungulwa kusuka kuma-crystal ingots akhuliswe kusetshenziswa indlela efana ne-Czochralski. Ama-ingots abe esesikwa abe ama-wafers amancane, apholishwe abe yindawo eyisicaba ngokuphelele, bese ehlanzwa ngamakhemikhali.
Ikhwalithi ye-wafer inquma isivuno (iphesenti lama-chips aphumelelayo). Ekwenziweni kwe-semiconductor, ngisho nezinhlayiya zothuli ezincane kakhulu zingabangela ukukhubazeka kudayi eyodwa (i-chip eyodwa) noma ngisho nendawo enkulu ye-wafer.
4. Inqubo yangaphambili: ukwakheka kwama-transistors namaseli enkumbulo
Isigaba esilandelayo ukwakha izingxenye ze-elekthronikhi ku-wafer ngokusebenzisa uchungechunge lwezinqubo eziphindaphindayo. Lokhu kuyisisekelo se-semiconductor “fab.”
a. Ukugcwala kwe-oksijini kanye nokufakwa kwezingqimba ezincane
I-wafer imbozwe ngesendlalelo esincane sezinto ezifana ne-silicon dioxide, i-silicon nitride, noma enye i-dielectric. Le sendlalelo singasebenza njengesivikelo, isivikelo, noma njengengxenye yesakhiwo se-transistor/capacitor.
b. I-Photolithography (i-photolithography)
I-Photolithography inqubo "yokudweba" iphethini yesekethe. I-wafer imbozwa nge-photoresist (into ezwela ukukhanya) bese ikhanyiswa ngemaski kusetshenziswa umshini we-lithography. Izindawo ezithile ziyaqina noma zincibilike (kuye ngohlobo lwe-resist), okudala iphethini. Le nqubo iphindaphindwa izikhathi eziningana ngeleveli ngayinye.
Kuma-node okukhiqiza anamuhla, i-lithography ingasebenzisa i-Deep Ultraviolet (DUV) noma i-Extreme Ultraviolet (EUV) ukukhiqiza izici ezincane kakhulu. Uma izici zincane, amaseli enkumbulo amaningi angapakishwa, umthamo uyanda, futhi ukusetshenziswa kwamandla kungancishiswa—nakuba ubunzima benqubo buyanda.
c. Ukuqopha
Uma iphethini seyakhiwe, izinto ezisendaweni ezithile zisuswa ngokusika okomile (i-plasma) noma ngokusika okumanzi (amakhemikhali) ukuze kwakheke isakhiwo esidingekayo.
d. Ukufaka i-doping kanye nokufakelwa kwama-ion
Ukuze i-transistor isebenze, izindawo ze-silicon kumele “zifakwe i-doped”—ukungcola okufana ne-boron noma i-phosphorus okungeziwe ukuze kwakhiwe izindawo ze-p-type kanye ne-n-type. Lokhu kufezwa ngokufakelwa kwe-ion kulandelwe inqubo yokushisa (yokushisa) ukuze kuhlungwe ikristalu futhi kusebenze ama-dopants.
e. Ukwakheka kwama-capacitor e-DRAM
Isihluthulelo se-DRAM yi-capacitor yokugcina ishaja. Ngenxa yokuthi ama-capacitor kudingeka abe makhulu ngokwanele ukugcina ishaja efundekayo ngokuthembekile, kodwa indawo ye-chip ilinganiselwe, imiklamo ye-capacitor yenziwa ngemiklamo enezinhlangothi ezintathu (3D), njenge-trench noma ama-capacitor ahlanganisiwe, kuye ngobuchwepheshe. Izinto ze-dielectric ezine-high-k zivame ukusetshenziselwa ukwandisa amandla ngaphandle kokukhulisa usayizi obonakalayo.
Iseli le-DRAM ngokuvamile liqukethe i-transistor eyodwa kanye ne-capacitor eyodwa (1T1C). Ikhwalithi yalesi sakhiwo inquma izidingo zokuqina, isivinini, kanye nokuvuselela.
5. Inqubo yangemuva: izendlalelo zensimbi kanye nokuxhumana
Uma ama-transistors namaseli enkumbulo esebunjiwe, i-chip idinga "umgwaqo omkhulu" ukuze ithwale izimpawu namandla. Lokhu kwenziwa ngenqubo ye-back-end-of-line (BEOL): ukuhlanganiswa kwezingqimba eziningi zezixhumanisi zensimbi.
Izinto zensimbi ngokuvamile ziwubhedu olunesithiyo sokusabalalisa ukuvimbela ithusi ukuthi lingalimazi ezinye izendlalelo. Isendlalelo sokuvikela (i-dielectric) sifakwa phakathi kwezinsimbi ukuze kuncishiswe amandla ezinambuzane kanye nokuvuza kwesignali. Kuma-chips anamuhla, inani lezingqimba zensimbi lingaba likhulu kakhulu, ngalinye linephethini ehlukile yokuxhuma izigidi zezinto eziyizinkulungwane.
6. Ukuhlolwa, ukukala kanye nokulawulwa kwekhwalithi kuzo zonke izigaba
Kuyo yonke inqubo, ama-wafer ahlolwa njalo kusetshenziswa amathuluzi okukala: ama-microscope e-electron, ukulinganisa ubukhulu befilimu, ukuhlolwa kwamaphutha, kanye nokuhlaziywa kokumbozwa (ukunemba kwephethini ehlanganiswa phakathi kwezingqimba). Ngenxa yokuthi i-wafer eyodwa iqukethe amakhulu kuya ezinkulungwaneni zama-dies, amaphutha amancane angaba nomthelela omkhulu ezindleleni.
Izimboni ze-semiconductor zigcina amakamelo ahlanzekile ngezindinganiso eziqinile, njengoba izinhlayiya ezincane zingaphazamisa ukukhiqizwa. Abasebenzi bagqoka izingubo ezikhethekile, futhi ukuhamba komoya kulawulwa ukuze kuncishiswe ukungcola.
7. Uhlobo lwe-wafer: ukuhlolwa kokuqala ezingeni le-wafer
Ngemva kokuba zonke izendlalelo seziqediwe, i-wafer ayikakanqunywa. Isinyathelo esilandelayo sibizwa ngokuthi i-wafer probing noma i-wafer sorting. Izinaliti ze-probe zithinta amaphedi okuhlola kudayi ngayinye ukuhlola imisebenzi eyisisekelo: ukuthi amaseli ememori angabhalwa futhi afundwe kusuka kuphi, ukuthi ngabe kukhona izindawo ezinephutha, kanye nezici zikagesi njengokuvuza nokusetshenziswa kwamandla.
Imiphumela idwetshwe kumephu (imephu ye-wafer) ukuze kutholakale ama-dies amahle namaphutha. Kuleli qophelo, inkampani ihlola futhi isivuno bese ilungisa inqubo uma kutholakala amaphethini athile amaphutha.
8. Ukusika: ukusika i-wafer ibe yizicucu
Ama-wafer ahlolwe anqunywa abe ama-chips amancane (ama-dies) kusetshenziswa i-diamond saw noma i-laser. Ama-dies anephutha avame ukulahlwa. Lawo aphumelela ukuhlolwa abe eseqhubekela esigabeni sokupakisha.
9. Ukupakisha: ukuguqula idayisi ibe yi-chip elungele ukusetshenziswa
Ukupakisha kungaphezu nje "kokusonga"; kuqinisekisa ukuthi i-chip ingaxhunywa ebhodini lesifunda, ivikelwe, futhi ikwazi ukuqeda ukushisa.
Kwi-RAM yethebhulethi, ukupakishwa okuvame kakhulu yi-BGA (Ball Grid Array) noma uhlobo oluncane kakhulu njenge-FBGA, ngokuvamile olunezilungiselelo ezifanele i-LPDDR. Kulesi sigaba, idayisi iboshelwe ku-substrate, ixhunywe kusetshenziswa i-wire bonding noma i-flip-chip, bese kufakwa amabhola e-solder ukuze ayixhume ku-motherboard.
Ngenxa yokuthi amaphilisi mancane kangaka, ubukhulu nokuphakama kwephakheji ye-chip kubalulekile. Abakhiqizi bakhetha amaphakheji amancane kodwa agcina ubuqotho besignali ephezulu, uma becabanga ukuthi i-RAM isebenza ngesivinini esiphezulu futhi iyazwela ekuphazamisekeni.
10. Ukuhlolwa kokugcina, ukugcinwa kwe-binning, kanye nokuhlanganiswa kuthebhulethi
Ama-chip apakishiwe aphinde ahlolwe esivivinyweni sokugcina. Ukuhlolwa kufaka phakathi isivinini esiphezulu, ukusetshenziswa kwamandla, ukuzinza emazingeni okushisa ahlukene, kanye nokuthembeka. Ukusuka lapho, kwenziwa ukugcinwa kwe-binning: ama-chip ahlukaniswa ngokusekelwe ekusebenzeni kahle. Ama-chip angasebenza ngokuqina kuma-frequency aphezulu abekwa ekilasini le-premium, kanti lawo azinzile kuphela ezimisweni ezijwayelekile abekwa kwelinye ikilasi.
Ngemva kokudlula ukuhlolwa, i-chip ithunyelwa esitshalweni sokuhlanganisa idivayisi. Ngesikhathi sesigaba sokuhlanganiswa, i-RAM ifakwa ebhodini lesekhethi lethebhulethi, ihlolwe kanye ne-SoC, bese idlula ezivivinyweni zokuqinisekisa ikhwalithi yedivayisi njengokuhlolwa kokucindezeleka, ukuhlolwa kokuwa, kanye nokuhlolwa kokushisa.
I-Penutup
Inqubo yokukhiqiza ama-RAM chips amathebulethi iyinhlanganisela yomklamo ocophelelayo, amasu okukhiqiza anembile nge-nanometer, kanye nokulawulwa kwekhwalithi okuqinile kuzo zonke izinyathelo. Kusukela kumakristalu e-silicon ahlanzekile kuya kumaphakheji e-LPDDR RAM asebenzisa amandla kahle, konke kudalwa ngochungechunge lwezinqubo eziphindaphindayo—i-lithography, i-deposition, i-etching, i-doping, ukwakheka kwe-capacitor, ukuxhumana kwensimbi, ukuhlolwa kwe-wafer, ukusika, kanye nokupakishwa kanye nokuhlolwa kokugcina. Ngenkathi i-RAM ingase ibonakale njengenombolo nje yomthamo kubasebenzisi bethebulethi, ngemuva kwayo kulele ubuchwepheshe bokukhiqiza obushintsha njalo obenza amadivayisi asheshe, asebenze kahle, futhi athembeke kakhudlwana.
Uma ungathanda, ngingangeza nesigaba esikhethekile mayelana nomehluko phakathi kwe-LPDDR4X ne-LPDDR5, noma ngingene emininingwaneni yobuchwepheshe eyengeziwe mayelana nesakhiwo samaseli e-DRAM kanye nenqubo ye-lithography ye-EUV.
