Menene wafer dicing?

A waferdole ne ya bi ta sauye-sauye guda uku don zama guntu na ainihi na semiconductor: na farko, an yanke ingot mai siffar toshe cikin wafers; a cikin tsari na biyu, ana zana transistor a gaban wafer ta hanyar da ta gabata; a ƙarshe, ana yin marufi, wato, ta hanyar yanke tsari, dawaferya zama cikakken guntu semiconductor. Ana iya ganin cewa tsarin marufi yana cikin tsarin baya-baya. A cikin wannan tsari, za a yanke wafer zuwa guntu guda ɗaya na hexahedron da yawa. Wannan tsari na samun kwakwalwan kwamfuta masu zaman kansu ana kiransa “Singulation”, kuma tsarin tsinke katakon wafer a cikin cuboids masu zaman kansu ana kiransa “yanke wafer (Die Sawing)”. Kwanan nan, tare da haɓaka haɗin gwiwar semiconductor, kauri nawafersya zama bakin ciki kuma ya zama mai laushi, wanda ba shakka yana kawo matsala mai yawa ga tsarin "singulation".

Juyin wafer dicing

Tsarin gaba-gaba da baya-baya sun samo asali ta hanyar hulɗa ta hanyoyi daban-daban: juyin halitta na tsarin baya zai iya ƙayyade tsari da matsayi na ƙananan kwakwalwan kwakwalwan hexahedron da aka rabu da mutuwa akanwafer, kazalika da tsari da matsayi na pads (hanyoyin haɗin wutar lantarki) akan wafer; akasin haka, juyin halittar gaba-gaba ya canza tsari da hanyarwaferbaya thinning da "mutu dicing" a baya-karshen tsari. Sabili da haka, haɓakar haɓakar bayyanar fakitin zai sami babban tasiri akan tsarin baya. Haka kuma, lamba, tsari da nau'in dicing suma zasu canza daidai gwargwadon canjin bayyanar fakitin.

Rubuta Dicing

A cikin kwanakin farko, "karya" ta hanyar amfani da karfi na waje ita ce kawai hanyar dicing da za ta iya rarrabawafercikin hexahedron ya mutu. Koyaya, wannan hanyar tana da lahani na guntu ko fashe gefen ƙaramin guntu. Bugu da ƙari, tun da ba a cire burrs a kan karfen karfe ba gaba daya, yanki da aka yanke shi ma yana da wahala sosai.
Don magance wannan matsalar, hanyar yanke “Scribing” ta kasance, wato kafin “karya”, saman ɓangarorin.waferan yanke zuwa kusan rabin zurfin. “Rubuta”, kamar yadda sunan ke nunawa, yana nufin yin amfani da abin motsa jiki don ganin (yanke rabin) gefen gaba na wafer a gaba. A cikin farkon kwanakin, yawancin wafers da ke ƙasa da inci 6 sun yi amfani da wannan hanyar yanke na farko "yanka" tsakanin kwakwalwan kwamfuta sannan kuma "karya".

Dicing Blade ko Sawing Blade

Hanyar yankan “Scribing” sannu a hankali ta zama hanyar yankan “Blade dicing” (ko sawing), wato hanyar yankan ta amfani da ruwa sau biyu ko uku a jere. Hanyar yankan "Blade" na iya daidaita yanayin ƙananan kwakwalwan kwamfuta da ke barewa lokacin "karya" bayan "rubuta", kuma yana iya kare ƙananan kwakwalwan kwamfuta yayin aiwatar da "singulation". Yanke "Blade" ya bambanta da yankan "dicing" na baya, wato, bayan yankan "blade", ba "karya" ba ne, amma sake yankewa tare da ruwa. Don haka, ana kuma kiransa hanyar “step dicing”.

Don kare wafer daga lalacewa ta waje yayin aikin yankewa, za a yi amfani da fim a kan wafer a gaba don tabbatar da "singling" mafi aminci. A lokacin aikin "baya niƙa", za a haɗa fim ɗin zuwa gaban wafer. Amma akasin haka, a cikin yankan "blade", ya kamata a haɗe fim ɗin zuwa baya na wafer. A lokacin eutectic die bonding (mutu bonding, gyara raba kwakwalwan kwamfuta a kan PCB ko kafaffen firam), fim din da aka makala a baya zai fadi ta atomatik. Saboda babban gogayya yayin yankan, ya kamata a fesa ruwan DI gabaɗaya daga kowane kwatance. Bugu da ƙari, ya kamata a haɗa impeller tare da barbashi na lu'u-lu'u domin a iya yanka yankan da kyau. A wannan lokacin, yanke (kauri mai kauri: tsagi nisa) dole ne ya zama iri ɗaya kuma kada ya wuce nisa na dicing.
Da dadewa, sarewar itace ita ce hanyar yankan gargajiya da aka fi amfani da ita. Babban fa'idarsa shine cewa zai iya yanke babban adadin wafers a cikin ɗan gajeren lokaci. Koyaya, idan saurin ciyarwar yanki ya ƙaru sosai, yuwuwar bawon gefen chiplet zai ƙaru. Sabili da haka, ya kamata a sarrafa adadin jujjuyawar na'urar a kusan sau 30,000 a minti daya. Ana iya ganin cewa fasaha na tsarin semiconductor sau da yawa asiri ne da aka tara a hankali ta hanyar dogon lokaci na tarawa da gwaji da kuskure (a cikin sashe na gaba game da haɗin gwiwar eutectic, za mu tattauna abubuwan da ke ciki game da yanke da DAF).

Dicing kafin nika (DBG): jerin yanke ya canza hanyar

Lokacin da ake yin yankan ruwan wukake akan wafer diamita 8-inch, babu buƙatar damuwa game da bawon gefen chiplet ko fashewa. Amma yayin da diamita na wafer ya ƙaru zuwa inci 21 kuma kauri ya zama siriri sosai, bawo da fashe abubuwan sun fara bayyana kuma. Domin rage yawan tasirin jiki akan wafer yayin aikin yankewa, hanyar DBG na "dicing kafin niƙa" ya maye gurbin tsarin yankan gargajiya. Ba kamar hanyar yankan “blade” na gargajiya da ke yanke ci gaba ba, DBG ta fara yin yankan “blade”, sannan a hankali tana rage kaurin wafer ta ci gaba da rage gefen baya har guntu ya rabu. Ana iya cewa DBG sigar haɓaka ce ta hanyar yankan “blade” da ta gabata. Saboda yana iya rage tasirin yanke na biyu, hanyar DBG ta shahara cikin sauri a cikin "marufi-matakin wafer".

Laser Dicing

Tsarin sikelin sikelin wafer (WLCSP) yana amfani da yankan Laser. Yankewar Laser na iya rage al'amura kamar kwasfa da fatattaka, don haka samun ingantattun kwakwalwan kwamfuta, amma lokacin da kaurin wafer ya fi 100μm, za a rage yawan aiki sosai. Sabili da haka, ana amfani da shi mafi yawa akan wafers tare da kauri wanda bai wuce 100μm (danganin bakin ciki). Yankewar Laser yana yanke siliki ta hanyar amfani da Laser mai ƙarfi a cikin tsagi na wafer. Koyaya, lokacin amfani da hanyar yanke Laser na al'ada (Laser na al'ada), dole ne a yi amfani da fim mai kariya a saman wafer a gaba. Saboda dumama ko haskaka saman wafer tare da Laser, waɗannan lambobin sadarwa na jiki za su haifar da tsagi a saman wafer, kuma gutsurer siliki da aka yanke kuma za su manne da saman. Ana iya ganin cewa hanyar yankan Laser ta gargajiya ta kuma yanke saman wafer kai tsaye, kuma a wannan yanayin, yana kama da hanyar yankan "blade".

Stealth Dicing (SD) hanya ce ta farko ta yanke ciki na wafer da makamashin Laser, sannan a yi amfani da matsi na waje a tef ɗin da aka makala a baya don karya shi, ta yadda za a raba guntu. Lokacin da aka matsa lamba akan tef ɗin a baya, za a ɗaga wafer ɗin nan take zuwa sama saboda miƙewar tef ɗin, ta yadda za a raba guntu. Amfanin SD akan hanyar yankan Laser na gargajiya sune: na farko, babu tarkacen silicon; na biyu, kerf (Kerf: nisa na tsagi mai rubutun) yana da kunkuntar, don haka ana iya samun ƙarin kwakwalwan kwamfuta. Bugu da kari, za a rage yawan kwasfa da fashewa ta hanyar amfani da hanyar SD, wanda ke da mahimmanci ga ingancin yanke gabaɗaya. Saboda haka, hanyar SD tana da yuwuwar zama fasaha mafi shahara a nan gaba.

Plasma Dicing
Yanke Plasma fasaha ce da aka haɓaka kwanan nan wacce ke amfani da etching plasma don yanke yayin aikin masana'anta (Fab). Yankewar Plasma yana amfani da kayan iskar gas a maimakon ruwa, don haka tasirin muhalli kadan ne. Kuma ana amfani da hanyar yanke duk wafer a lokaci ɗaya, don haka saurin "yanke" yana da sauri. Duk da haka, hanyar plasma tana amfani da iskar gas ɗin sinadarai a matsayin ɗanyen abu, kuma tsarin etching yana da rikitarwa sosai, don haka tafiyar da tsarinsa yana da ɗan wahala. Amma idan aka kwatanta da yankan "blade" da yankan Laser, yankan plasma baya haifar da lalacewa ga farfajiyar wafer, don haka rage ƙarancin lahani da samun ƙarin kwakwalwan kwamfuta.

Kwanan nan, tun lokacin da aka rage kaurin wafer zuwa 30μm, kuma ana amfani da jan karfe (Cu) da yawa ko ƙananan dielectric akai-akai (Low-k). Don haka, don hana burrs (Burr), hanyoyin yankan plasma suma za a fifita su. Tabbas, fasahar yankan plasma kuma tana haɓaka koyaushe. Na yi imani cewa nan gaba kadan, wata rana ba za a sami buƙatar sanya abin rufe fuska na musamman ba yayin da ake yin etching, saboda wannan shine babban jagorar ci gaba na yanke plasma.

Kamar yadda kauri na wafers an ci gaba da rage daga 100μm zuwa 50μm sannan zuwa 30μm, hanyoyin yankan don samun kwakwalwan kwamfuta masu zaman kansu kuma suna canzawa da haɓakawa daga "karye" da "blade" zuwa yankan Laser da yankan plasma. Ko da yake hanyoyin da ake ƙara balagagge sun ƙara yawan kuɗin da ake samarwa na aikin yankan da kansa, a gefe guda, ta hanyar rage yawan abubuwan da ba a so kamar bawo da fatattaka waɗanda galibi ke faruwa a yankan guntu na semiconductor da ƙara adadin kwakwalwan kwamfuta da aka samu kowace naúrar wafer. , farashin samar da guntu guda ɗaya ya nuna yanayin ƙasa. Tabbas, karuwar adadin kwakwalwan kwamfuta da aka samu a kowane yanki na wafer yana da alaƙa da raguwar nisa na titin dicing. Yin amfani da yankan plasma, ana iya samun kusan 20% ƙarin kwakwalwan kwamfuta idan aka kwatanta da yin amfani da hanyar yanke “blade”, wanda kuma shine babban dalilin da ya sa mutane ke zaɓar yankan plasma. Tare da haɓakawa da canje-canje na wafers, bayyanar guntu da hanyoyin marufi, matakai daban-daban na yanke kamar fasahar sarrafa wafer da DBG suma suna fitowa.