Kuyenda kwa njira ya semiconductor

Mukhoza kumvetsa ngakhale simunaphunzirepo sayansi ya fizikisi kapena masamu, koma ndi yosavuta komanso yoyenera oyamba kumene. Ngati mukufuna kudziwa zambiri za CMOS, muyenera kuwerenga zomwe zili mu nkhaniyi, chifukwa pokhapokha mutamvetsetsa momwe njira imayendera (ndiko kuti, njira yopangira diode) ndi pomwe mungapitirize kumvetsetsa zomwe zili pansipa. Kenako tiyeni tiphunzire momwe CMOS iyi imapangidwira mu kampani yopanga maziko munkhaniyi (potengera njira yosakhala yapamwamba mwachitsanzo, CMOS ya njira yotsogola ndi yosiyana mu kapangidwe ndi mfundo yopangira).

Choyamba, muyenera kudziwa kuti ma wafer omwe fakitale ya foundation imapeza kuchokera kwa wogulitsa (chokulungira cha silikoniogulitsa) ndi amodzi ndi amodzi, okhala ndi utali wa 200mm (Mainchesi 8fakitale) kapena 300mm (Mainchesi 12fakitale). Monga momwe chithunzi chili pansipa chikusonyezera, kwenikweni chikufanana ndi keke yayikulu, yomwe timaitcha kuti substrate.

Komabe, sizoyenera kuti tizione motere. Timayang'ana kuchokera pansi kupita mmwamba ndikuyang'ana mawonekedwe opingasa, omwe amakhala chithunzi chotsatirachi.

Kenako, tiyeni tiwone momwe chitsanzo cha CMOS chikuwonekera. Popeza njira yeniyeniyo imafuna masitepe ambirimbiri, ndilankhula za masitepe akuluakulu a wafer yosavuta kwambiri ya mainchesi 8 pano.

 

 

Kupanga Chitsime ndi Chigawo Chosinthira:

Ndiko kuti, chitsimecho chimayikidwa mu substrate pogwiritsa ntchito ion implantation (Ion Implantation, yomwe ikutchedwa imp pano). Ngati mukufuna kupanga NMOS, muyenera kuika zitsime za P-type. Ngati mukufuna kupanga PMOS, muyenera kuika zitsime za N-type. Kuti zinthu zikuyendereni bwino, tiyeni titenge NMOS mwachitsanzo. Makina oika ma ion amaika zinthu za P-type zomwe ziyenera kuyikidwa mu substrate mpaka kuzama kwina, kenako amazitentha kutentha kwambiri mu chubu cha ng'anjo kuti ayambitse ma ion awa ndikuwafalitsa mozungulira. Izi zimamaliza kupanga chitsimecho. Umu ndi momwe zimaonekera pambuyo poti kupanga kwatha.

Pambuyo popanga chitsime, pali njira zina zoyikira ma ion, zomwe cholinga chake ndikuwongolera kukula kwa mphamvu ya channel ndi voltage yolowera. Aliyense akhoza kutcha kuti inversion layer. Ngati mukufuna kupanga NMOS, inversion layer imayikidwa ndi ma P-type ions, ndipo ngati mukufuna kupanga PMOS, inversion layer imayikidwa ndi ma N-type ions. Pambuyo poyikira, ndi chitsanzo chotsatirachi.

Pali zambiri zomwe zili pano, monga mphamvu, ngodya, kuchuluka kwa ma ion panthawi yoika ma ion, ndi zina zotero, zomwe sizikuphatikizidwa mu nkhaniyi, ndipo ndikukhulupirira kuti ngati mukudziwa zinthu zimenezo, muyenera kukhala munthu wamkati, ndipo muyenera kukhala ndi njira yoziphunzirira.

 

Kupanga SiO2:

Silicon dioxide (SiO2, yomwe ikutchedwa oxide pano) idzapangidwa pambuyo pake. Mu njira yopangira CMOS, pali njira zambiri zopangira oxide. Pano, SiO2 imagwiritsidwa ntchito pansi pa chipata, ndipo makulidwe ake amakhudza mwachindunji kukula kwa voltage yolowera ndi kukula kwa channel current. Chifukwa chake, ma foundry ambiri amasankha njira yothira ng'anjo ya chubu yokhala ndi khalidwe lapamwamba kwambiri, kuwongolera kolondola kwambiri kwa makulidwe, komanso kufanana kwabwino kwambiri pa sitepe iyi. Ndipotu, ndikosavuta kwambiri, ndiko kuti, mu chubu cha ng'anjo chokhala ndi mpweya, kutentha kwakukulu kumagwiritsidwa ntchito kuti mpweya ndi silicon zichitepo kanthu mwa mankhwala kuti zipange SiO2. Mwanjira imeneyi, wosanjikiza woonda wa SiO2 umapangidwa pamwamba pa Si, monga momwe zasonyezedwera pachithunzi pansipa.

Inde, palinso zambiri zenizeni apa, monga kuchuluka kwa madigiri omwe akufunika, kuchuluka kwa mpweya womwe ukufunika, kutalika kwa kutentha kwakukulu komwe kukufunika, ndi zina zotero. Izi si zomwe tikuganizira tsopano, izi ndi zenizeni kwambiri.

Kupanga kwa gate end Poly:

Koma sizinathebe. SiO2 ndi yofanana ndi ulusi, ndipo chipata chenicheni (Poly) sichinayambebe. Chifukwa chake gawo lathu lotsatira ndikuyika polysilicon pa SiO2 (polysilicon imapangidwanso ndi chinthu chimodzi cha silicon, koma kapangidwe ka lattice ndi kosiyana. Musandifunse chifukwa chake substrate imagwiritsa ntchito silicon imodzi ya kristalo ndipo chipata chimagwiritsa ntchito polysilicon. Pali buku lotchedwa Semiconductor Physics. Mutha kuphunzira za izi. Ndizochititsa manyazi ~). Poly ndi ulalo wofunikira kwambiri mu CMOS, koma gawo la poly ndi Si, ndipo silingapangidwe ndi reaction yolunjika ndi substrate ya Si monga kukula kwa SiO2. Izi zimafuna CVD yodziwika bwino (Chemical Vapor Deposition), yomwe imachitapo kanthu mwa mankhwala mu vacuum ndikuyambitsa chinthu chopangidwa pa wafer. Mu chitsanzo ichi, chinthu chopangidwa ndi polysilicon, kenako chimayikidwa pa wafer (apa ndiyenera kunena kuti poly imapangidwa mu chubu cha uvuni ndi CVD, kotero kupanga poly sikumachitika ndi makina a CVD oyera).

Koma polysilicon yopangidwa ndi njira iyi idzagwera pa wafer yonse, ndipo imawoneka motere mvula ikagwa.

 

Kuwonetsedwa kwa Poly ndi SiO2:

Pa sitepe iyi, kapangidwe koyima komwe tikufuna kapangidwadi, ndi poly pamwamba, SiO2 pansi, ndi substrate pansi. Koma tsopano wafer yonse ili motere, ndipo tikungofunika malo enieni kuti ikhale kapangidwe ka "faucet". Chifukwa chake pali gawo lofunika kwambiri mu ndondomeko yonseyi - kuonekera.
Choyamba timayika chinthu choteteza kuwala pamwamba pa wafer, ndipo chimakhala chonchi.

Kenako ikani chigoba chodziwika bwino (kapangidwe ka dera kamene kafotokozedwa pa chigobacho), ndipo potsiriza chiwalireni ndi kuwala kwa kutalika kwa nthawi inayake. Chotsutsa kuwala chidzayamba kugwira ntchito m'dera lomwe lakhudzidwa ndi kuwala. Popeza malo otsekedwa ndi chigobacho sakuwunikiridwa ndi gwero la kuwala, chidutswa ichi cha chotsutsa kuwala sichikuwunikiridwa.

Popeza kuti photoresist yogwira ntchito ndi yosavuta kutsukidwa ndi madzi enaake a mankhwala, pomwe photoresist yosagwira ntchito singatsukidwe, pambuyo pa kuwala kwa dzuwa, madzi enaake amagwiritsidwa ntchito kutsuka photoresist yogwira ntchito, ndipo pamapeto pake zimakhala motere, kusiya photoresist komwe Poly ndi SiO2 ziyenera kusungidwa, ndikuchotsa photoresist komwe sikufunikira kusungidwa.