Tsarin yin kwakwalwan RAM don kwamfutar hannu
RAM (Random Access Memory) yana ɗaya daga cikin muhimman abubuwan da ke cikin kwamfutar hannu. Ba tare da RAM ba, kwamfutar hannu ba za ta iya gudanar da aikace-aikace cikin sauƙi ba, canzawa tsakanin ayyuka da sauri, ko kuma kula da martani lokacin da ayyuka da yawa ke gudana a lokaci guda. Duk da ƙaramin girmansu da kuma a ɗaure su sosai a cikin na'urar, guntun RAM sakamakon wani tsari mai rikitarwa, mai inganci wanda ya ƙunshi ɗaruruwan matakai. Wannan labarin ya ƙunshi manyan matakai a cikin tsarin ƙera guntun RAM da aka saba amfani da su a cikin kwamfutar hannu—yawanci nau'in LPDDR (Ƙarancin Power Double Data Rate), kamar yadda aka tsara su don su kasance masu amfani da makamashi.
1. Tsarin gine-gine da ƙayyadaddun bayanai
Tsarin yana farawa tun kafin guntu na zahiri ya kasance a wurin. Ƙungiyoyin ƙira a kamfanonin semiconductor suna ƙayyade buƙatun kasuwar kwamfutar hannu: ƙarfin aiki (misali, 4GB, 8GB, 12GB), bandwidth, amfani da wutar lantarki, da kuma dacewa da tsarin-on-chip (SoC). Ga kwamfutar hannu ta zamani, RAM dole ne ya daidaita aiki da ingancin baturi. Saboda haka, ana amfani da ƙa'idodi kamar LPDDR4X ko LPDDR5/LPDDR5X sau da yawa.
A cikin tsarin ƙira, injiniyoyi kuma suna haɓaka tsarin ƙwayoyin ƙwaƙwalwa, bankunan ƙwaƙwalwa, hanyoyin bayanai (bas ɗin bayanai), da da'irori masu tallafi kamar amplifiers na ji, layuka/column decoders, da hanyoyin sabuntawa. DRAM ya bambanta da SRAM: DRAM yana adana bits ta amfani da ƙananan capacitors waɗanda dole ne a sabunta su lokaci-lokaci, yayin da SRAM ya fi sauri amma ya fi tsada kuma yana ɗaukar sarari.
2. Tsarin tsari da tabbatarwa
Da zarar an ayyana tsarin ginin, za a mayar da tsarin zuwa tsarin zahiri: cikakken taswirar matsayin transistor, capacitors, haɗin ƙarfe, da yadudduka da za a samar a kan wafer ɗin silicon. Wannan matakin yana buƙatar software na EDA (Electronic Design Automation) da kuma tsari mai tsauri na tabbatar da cewa ƙirar za a iya ƙera ta kuma tana aiki kamar yadda aka nufa.
Tabbatarwa ya haɗa da kwaikwayon lokaci, amfani da wutar lantarki, ƙarfin sarrafawa don bambancin sarrafawa, da gwajin dabaru don guje wa kurakurai masu haɗari waɗanda zasu iya haifar da gazawar dukkan rukunin wafer.
3. Kera wafers na silicon (substrates)
Ana yin guntun RAM a kan wafers ɗin silicon mai tsarki. Ana sarrafa silicon daga ingots ɗin lu'ulu'u da aka noma ta amfani da dabara irin ta Czochralski. Sannan ana yanka ingots ɗin zuwa siririn wafers, a goge su zuwa wuri mai faɗi sosai, sannan a tsaftace su da sinadarai.
Ingancin wafer yana ƙayyade yawan amfanin ƙasa (kashi na nasarar guntu). A cikin kera semiconductor, har ma ƙananan ƙura na iya haifar da lahani a kan mazubi ɗaya (guntu ɗaya) ko ma babban yanki na wafer.
4. Tsarin gaba: samuwar transistor da ƙwayoyin ƙwaƙwalwa
Mataki na gaba shine gina sassan lantarki a kan wafer ta hanyar jerin hanyoyin da ake maimaitawa. Wannan shine ainihin "fab" na semiconductor.
a. Haɓaka iskar oxygen da kuma ɓoyewar siraran Layer
Ana shafa wafer ɗin da wani siririn abu kamar silicon dioxide, silicon nitride, ko wani dielectric. Wannan Layer ɗin zai iya aiki a matsayin insulator, garkuwa, ko kuma a matsayin wani ɓangare na tsarin transistor/capacitor.
b. Photolithography (photolithography)
Photolithography tsari ne na "zane" tsarin da'ira. Ana shafa wafer ɗin da mai hana haske (wani abu mai saurin haske) sannan a haskaka shi ta hanyar abin rufe fuska ta amfani da injin lithography. Wasu wurare suna taurare ko narkewa (ya danganta da nau'in juriya), suna ƙirƙirar tsarin. Ana maimaita wannan tsari sau da yawa ga kowane layi.
A cikin na'urorin zamani na masana'antu, lithography na iya amfani da Deep Ultraviolet (DUV) ko Extreme Ultraviolet (EUV) don samar da ƙananan siffofi. Yayin da ƙananan siffofin ke ƙaruwa, ana iya tattara ƙwayoyin ƙwaƙwalwa da yawa, ƙarfin aiki yana ƙaruwa, kuma ana iya rage yawan amfani da wutar lantarki - duk da cewa sarkakiyar tsari tana ƙaruwa.
c. Sassaka
Da zarar an samar da tsarin, ana cire kayan da ke wasu wurare ta hanyar busasshen fenti (plasma) ko kuma fenti mai laushi (sinadarai) don samar da tsarin da ake buƙata.
d. Yin amfani da maganin hana shan kwayoyi da kuma dasa ion
Domin transistor ya yi aiki, dole ne a "yi amfani da na'urar lantarki" a yankunan silicon—datti kamar boron ko phosphorus da aka ƙara don samar da yankunan nau'in p da nau'in n. Ana samun wannan ta hanyar dasa ion sannan a bi tsarin dumama (dumamawa) don tausasa lu'ulu'u da kuma kunna abubuwan da ke cikinsa.
e. Samar da na'urorin DRAM masu ƙarfin lantarki
Mabuɗin DRAM shine capacitor na ajiyar caji. Saboda capacitors suna buƙatar girma sosai don adana caji mai iya karantawa, amma yankin guntu yana da iyaka, ana yin ƙirar capacitor a cikin ƙira mai girma uku (3D), kamar rami ko capacitors masu tarin yawa, ya danganta da fasahar. Sau da yawa ana amfani da kayan dielectric masu ƙarfi don ƙara ƙarfin ba tare da ƙara girman jiki ba.
Kwayar DRAM yawanci tana ƙunshe da transistor ɗaya da capacitor ɗaya (1T1C). Ingancin wannan tsari yana ƙayyade buƙatun kwanciyar hankali, gudu, da wartsakewa.
5. Tsarin baya: yadudduka na ƙarfe da haɗin kai
Da zarar an samar da transistor da ƙwayoyin ƙwaƙwalwa, guntu yana buƙatar "hanyar" don ɗaukar sigina da ƙarfi. Ana yin wannan ta hanyar tsarin baya-bayan-layi (BEOL): tara layuka da yawa na haɗin ƙarfe.
Kayan ƙarfe yawanci jan ƙarfe ne mai shingen yaɗuwa don hana jan ƙarfe lalata sauran layukan. Ana saka wani Layer mai hana ruwa shiga (dielectric) tsakanin ƙarfe don rage ƙarfin parasitic capacitance da ɗigon sigina. A cikin kwakwalwan zamani, adadin layukan ƙarfe na iya zama da yawa, kowannensu yana da tsari na musamman don haɗa miliyoyin abubuwa zuwa biliyoyin abubuwa.
6. Dubawa, nazarin ƙasa da kuma kula da inganci a kowane mataki
A duk tsawon wannan tsari, ana ci gaba da duba wafers ta amfani da kayan aikin nazarin yanayin ƙasa: na'urorin microscope na lantarki, ma'aunin kauri na fim, gwajin lahani, da kuma nazarin rufewa (sakamakon tsarin da ke tarawa tsakanin yadudduka). Saboda wafer ɗaya yana ɗauke da ɗaruruwan zuwa dubban matattun abubuwa, ƙananan kurakurai na iya yin tasiri mai mahimmanci akan farashi.
Masana'antun Semiconductor suna kula da dakunan tsafta tare da ƙa'idodi masu tsauri, saboda ƙananan ƙwayoyin cuta na iya kawo cikas ga samarwa. Masu aiki suna sanya tufafi na musamman, kuma ana daidaita iskar iska don rage gurɓatawa.
7. Rarraba Wafer: gwaji na farko a matakin Wafer
Bayan an kammala dukkan layuka, ba a yanke wafer ɗin ba tukuna. Mataki na gaba ana kiransa wafer probing ko wafer rarrabuwa. Allurar bincike tana taɓa kushin gwaji a kan kowace na'urar don duba ayyukan asali: ko ana iya rubuta ƙwayoyin ƙwaƙwalwa zuwa da karantawa daga gare su, ko akwai wasu wurare masu lahani, da halayen lantarki kamar zubewa da amfani da wutar lantarki.
An tsara sakamakon (taswirar wafer) don gano ma'aunin inganci da nakasa. A wannan lokacin, kamfanin yana kuma kimanta yawan amfanin ƙasa kuma yana daidaita tsarin idan an gano wasu alamu na lahani.
8. Yanka: yanke wafer ɗin zuwa gawayi
Ana yanka wafers ɗin da aka gwada zuwa ƙananan guntu (di) ta amfani da na'urar yanke lu'u-lu'u ko laser. Galibi ana jefar da na'urorin kashe gobara masu lahani. Waɗanda suka ci jarrabawar sai su ci gaba zuwa matakin marufi.
9. Marufi: canza marufin zuwa guntu mai shirye don amfani
Marufi ya fi "naɗewa" kawai; yana tabbatar da cewa za a iya haɗa guntu da allon da'ira, a kare shi, kuma a iya kawar da zafi.
Ga kwamfutar hannu, marufi mafi yawan gaske shine BGA (Ball Grid Array) ko wani nau'in da ya fi ƙarami kamar FBGA, sau da yawa tare da tsari wanda ya dace da LPDDR. A wannan matakin, ana haɗa marufin da substrate, an haɗa shi ta amfani da haɗin waya ko flip-chip, sannan a ƙara ƙwallon solder don haɗa shi da motherboard.
Saboda ƙwayoyin cuta suna da sirara sosai, girman da tsayin na'urar guntu suna da matuƙar muhimmanci. Masu kera suna zaɓar fakitin da suka yi ƙanƙanta amma suna riƙe da ingantaccen sigina, la'akari da cewa RAM yana aiki a babban gudu kuma yana da saurin shiga tsakani.
10. Gwaji na ƙarshe, yin amfani da na'urar ɓoye bayanai, da haɗa kwamfutar hannu
Ana sake gwada kwakwalwan da aka fakiti a gwaji na ƙarshe. Gwaji ya haɗa da matsakaicin gudu, amfani da wutar lantarki, kwanciyar hankali a yanayin zafi daban-daban, da aminci. Daga nan, ana yin binning: ana haɗa kwakwalwan bisa ga aiki. Ana sanya kwakwalwan da za su iya aiki da kyau a mafi yawan mitoci a cikin aji na musamman, yayin da waɗanda ba su da ƙarfi kawai a takamaiman ƙayyadaddun bayanai ana sanya su a cikin wani aji.
Bayan an ci jarrabawar, ana aika guntu zuwa wurin haɗa na'urorin. A lokacin haɗawar, ana haɗa RAM ɗin zuwa allon da'irar kwamfutar, a gwada shi tare da SoC, sannan a yi gwajin tabbatar da inganci na matakin na'ura kamar gwajin damuwa, gwajin raguwa, da gwajin zafin jiki.
Penutup
Tsarin ƙera kwakwalwan RAM na kwamfutar hannu haɗuwa ce ta ƙira mai kyau, dabarun ƙera daidai-daidai na nanometer, da kuma ingantaccen kula da inganci a kowane mataki. Daga lu'ulu'u na silicon masu tsarki zuwa fakitin RAM na LPDDR masu amfani da ƙarfi, komai ana ƙirƙira shi ta hanyar jerin hanyoyin maimaitawa - lithography, deposition, etching, doping, capacitor formation, metal linking gear, wafer testing, yankewa, da marufi da kuma gwaji na ƙarshe. Duk da cewa RAM na iya zama kamar lambar ƙarfin aiki kawai ga masu amfani da kwamfutar hannu, a bayansa akwai fasahar ƙera da ke ci gaba da bunkasa wanda ke sa na'urori su yi sauri, inganci, da aminci.
Idan kuna so, zan iya ƙara wani sashe na musamman kan bambance-bambancen da ke tsakanin LPDDR4X da LPDDR5, ko kuma in shiga ƙarin bayani game da tsarin tantanin halitta na DRAM da tsarin lithography na EUV.
