Kucheneswa kwemvura kwekutanga kwakakurudzira kukura kwemaitiro ekuchenesa kana kudira dota. Nhasi, kucheneswa kwemvura kwava chinhu chikuru chinoshandiswa pakuchenesa kana kudira dota.maitiro ekuchekaPlasma ine maerekitironi, macationi nema radicali. Simba rinoshandiswa paplasma rinoita kuti maerekitironi ekunze egasi rinobva mumhepo ari mumamiriro asina kusimba abviswe, nokudaro achishandura maerekitironi aya kuita macationi.
Pamusoro pezvo, maatomu asina kukwana mumamorekuru anogona kubviswa nekushandisa simba kugadzira ma radical asina simba emagetsi. Kucheka kwakaoma kunoshandisa ma cations nema radicals anoumba plasma, uko ma cations ari anisotropic (akakodzera kuchekwa munzira yakati) uye ma radicals ari isotropic (akakodzera kuchekwa munzira dzese). Huwandu hwema radicals hwakakura zvikuru kupfuura huwandu hwema cations. Muchiitiko ichi, kuchekwa kwakaoma kunofanira kunge kuri isotropic sekuchekwa kwemvura.
Zvisinei, kuchekwa kweanisotropic kwekucheka kwakaoma ndiko kunoita kuti macircuit akachekwa zvakanyanya akwanise kukwanisika. Chii chinokonzera izvi? Pamusoro pezvo, kumhanya kwekucheka kwemacation nema radicals kunononoka zvikuru. Saka tingashandisa sei nzira dzekucheka plasma pakugadzira zvinhu zvakawanda tichitarisana nekusakwana uku?
1. Chiyero cheAspect (A/R)
Mufananidzo 1. Pfungwa yeaspect ratio uye mhedzisiro yekufambira mberi kwetekinoroji pairi
Aspect Ratio inhamba yehupamhi hwakatarwa kusvika pahurefu hwakatarwa (kureva, kureba kwakakamurwa nehupamhi). Kana chidimbu chakakosha (CD) chedunhu chikave chidiki, chiyero cheaspect ratio chinowedzera kukura. Kureva kuti, kana tichifunga kuti chiyero cheaspect ratio che10 uye upamhi hwe10nm, kukwirira kwegomba rakaboorwa panguva yekucheka kunofanira kunge kuri 100nm. Saka, kune zvigadzirwa zvechizvarwa chinotevera zvinoda ultra-miniaturization (2D) kana high density (3D), chiyero chepamusoro-soro chinodiwa kuti uve nechokwadi chekuti macations anogona kupinda mufirimu repasi panguva yekucheka.
Kuti uwane tekinoroji ye ultra-miniaturization ine chiyero chakakosha chepasi pe 10nm muzvigadzirwa zve 2D, capacitor aspect ratio value ye dynamic random access memory (DRAM) inofanira kuchengetedzwa pamusoro pe 100. Saizvozvowo, 3D NAND flash memory inodawo aspect ratio values yakakwira kuti iunganidze 256 layers kana kupfuura e cell stacking layers. Kunyangwe kana mamiriro anodiwa kune mamwe maitiro akazadzikiswa, zvigadzirwa zvinodiwa hazvigone kugadzirwa kanamaitiro ekuchekaHazvina kuenderana nezvinodiwa. Ndosaka tekinoroji yekucheka iri kuramba ichikosha.
2. Pfupiso ye plasma etching
Mufananidzo 2. Kuziva gasi rinobva muplasma zvichienderana nerudzi rwefirimu
Kana pombi isina chinhu ichishandiswa, dhayamita yepombi yacho ikanyanya kutetepa, zvinoita kuti mvura ipinde nyore, inova inonzi capillary phenomenon. Zvisinei, kana gomba (kumagumo akavharika) richizoboorwa munzvimbo yakavhurika, mvura yacho inopinza inova yakaoma zvikuru. Saka, sezvo saizi yakakosha yedunhu iri yaive 3um kusvika 5um pakati pemakore ekuma1970, mvura yakaoma.kutemazvishoma nezvishoma yakatsiva wet etching sechinhu chikuru. Izvi zvinoreva kuti, kunyangwe yakaitwa ion, zviri nyore kupinda mumakomba akadzika nekuti huwandu hwemorekuru imwe chete hudiki pane hwemorekuru ye organic polymer solution.
Panguva yekucheka plasma, mukati mekamuri rekugadzirisa rinoshandiswa pakucheka rinofanira kugadziriswa kuti rive vacuum state risati rapinza gasi rinobva muplasma rakakodzera layer yakakodzera. Pakucheka ma solid oxide films, magasi akasimba anobva mucarbon fluoride anofanira kushandiswa. Pamafirimu esilicon kana esimbi asina kusimba, magasi anobva muplasma anobva muchlorine anofanira kushandiswa.
Saka, gate layer ne silicon dioxide (SiO2) insulating layer zvinofanira kuchekwa sei?
Kutanga, kune gate layer, silicon inofanira kubviswa uchishandisa chlorine-based plasma (silicon + chlorine) ine polysilicon etching selectivity. Kune low insulating layer, silicon dioxide film inofanira kuchekwa nematanho maviri uchishandisa carbon fluoride-based plasma source gas (silicon dioxide + carbon tetrafluoride) ine etching selectivity yakasimba uye inoshanda.
3. Maitiro ekugadzira maion anopindirana (RIE kana physicochemical etching)
Mufananidzo 3. Mabhenefiti e reactive ion etching (anisotropy uye high etching rate)
Plasma ine isotropic free radicals uye anisotropic cations, saka inoita sei anisotropic etching?
Kucheka kwakaoma kweplasma kunonyanya kuitwa ne reactive ion etching (RIE, Reactive Ion Etching) kana mashandisirwo akavakirwa panzira iyi. Chinhu chikuru cheRIE method ndechekuderedza simba rekubatanidza pakati pemamorekuru ari mufirimu nekurwisa nzvimbo yekucheka ne anisotropic cations. Nzvimbo isina simba inotorwa ne free radicals, pamwe chete nezvidimbu zvinoumba layer, zvinoshandurwa kuita gasi (chinhu chinoshanduka kuita volatile) uye zvinoburitswa.
Kunyange hazvo ma free radicals aine hunhu hwe isotropic, mamorekuru anoumba pasi pemvura (ane simba rekusunga rinodzikiswa nekurwiswa kwema cations) anobatwa zviri nyore nema free radicals uye anoshandurwa kuita makomponi matsva pane madziro emativi ane simba rekusunga rakasimba. Nokudaro, kuchekwa kwepasi kunova chinhu chikuru. Zvidimbu zvakabatwa zvinova gasi rine free radicals, izvo zvinobviswa uye zvinoburitswa kubva pamusoro pasi pesimba re vacuum.
Panguva ino, macation anowanikwa nekuita kwemuviri uye mafree radicals anowanikwa nekuita kwemakemikari anosanganiswa kuti aite physical uye chemical etching, uye etching rate (Etch Rate, dhigirii re etching munguva yakati) inowedzerwa kagumi kana tichienzanisa ne cationic etching kana free radical etching chete. Nzira iyi haingogone kuwedzera etching rate ye anisotropic downward etching chete, asiwo kugadzirisa dambudziko re polymer residue mushure me etching. Nzira iyi inonzi reactive ion etching (RIE). Chinhu chikuru chekubudirira kwe RIE etching ndechekuwana plasma source gas yakakodzera etching firimu. Cherechedza: Plasma etching iRIE etching, uye maviri aya anogona kuonekwa sepfungwa imwe chete.
4. Etch Rate uye Core Performance Index
Mufananidzo 4. Core Etch Performance Index ine chekuita neEtch Rate
Mwero we etch zvinoreva kudzika kwefirimu kunotarisirwa kusvikwa muminiti imwe chete. Saka zvinorevei kuti mwero we etch unosiyana kubva pachikamu kuenda pane chimwe chikamu pa wafer imwe chete?
Izvi zvinoreva kuti kudzika kwe etch kunosiyana kubva pachikamu kuenda pane chimwe chiri pa wafer. Nekuda kweizvi, zvakakosha zvikuru kuisa poindi yekupedzisira (EOP) apo etching inofanira kumira nekufunga nezve avhareji ye etch rate uye kudzika kwe etch. Kunyangwe kana EOP yaiswa, kuchine dzimwe nzvimbo uko kudzika kwe etch kwakadzika (kwakaiswa zvakanyanya) kana kudzika (kwakaiswa zvishoma) kupfuura zvakarongwa pakutanga. Zvisinei, etching inokonzera kukuvara kwakanyanya kupfuura etching yakawandisa panguva ye etching. Nekuti kana iri etching isina kupiswa, chikamu chisina kupiswa chichakanganisa maitiro anotevera akadai se ion implantation.
Panguva iyi, kusarudza (kunoyerwa ne etch rate) chiratidzo chikuru chekushanda kwe etching process. Muyero wekuyera wakavakirwa pakuenzanisa etch rate ye mask layer (photoresist film, oxide film, silicon nitride film, nezvimwewo) uye target layer. Izvi zvinoreva kuti selectivity yakakwira, target layer inochekwa nekukurumidza. Kana miniaturization yakakwira, zvinodiwa zve selectivity ndezvekuona kuti ma fine patterns anogona kuratidzwa zvakakwana. Sezvo etching direction yakatwasuka, selectivity ye cationic etching yakaderera, nepo selectivity ye radical etching yakakwira, izvo zvinovandudza selectivity yeRIE.
5. Maitiro ekucheka
Mufananidzo 5. Maitiro ekucheka
Kutanga, wafer inoiswa muchoto cheoxidation ine tembiricha iri pakati pe800 ne1000℃, uye firimu resilicon dioxide (SiO2) rine hunhu hwakanyanya hwekuputira rinoumbwa pamusoro pewafer nenzira yakaoma. Tevere, nzira yekuisa inopinzwa kuti igadzire silicon layer kana conductive layer pa oxide film ne chemical vapor deposition (CVD)/physical vapor deposition (PVD). Kana silicon layer ikagadzirwa, nzira yekuisa tsvina inogona kuitwa kuti iwedzere conductivity kana zvichidikanwa. Munguva yekuisa tsvina, tsvina yakawanda inowanzowedzerwa kakawanda.
Panguva iyi, chivharo chekudzivirira kupisa ne polysilicon layer zvinofanira kusanganiswa kuti zviome. Kutanga, panoshandiswa photoresist. Zvadaro, chifukidzo chinoiswa pafirimu re photoresist uye kunyorova kunoitwa nekunyudza kuti patani inodiwa (isingaonekwe nemaziso) pafirimu re photoresist. Kana chimiro chepateni chaonekwa nekugadzirwa, photoresist iri munzvimbo inonzwa kupisa inobviswa. Zvadaro, wafer inogadziriswa ne photolithography process inotamisirwa kune etching process kuti iome etching.
Kucheka kwakaoma kunonyanya kuitwa ne reactive ion etching (RIE), umo kucheka kunodzokororwa kunyanya nekutsiva gasi rinobva rakakodzera firimu rega rega. Kucheka kwakaoma uye kuchekwa kwemvura zvese zvinovavarira kuwedzera chiyero cheaspect (A/R value) chekucheka. Pamusoro pezvo, kuchenesa nguva dzose kunodiwa kubvisa polymer yakaunganidzwa pasi pegomba (mukana unoumbwa nekuchekwa). Chinhu chakakosha ndechekuti zvese zvinoshanduka (senge zvinhu, gasi rinobva, nguva, chimiro uye kutevedzana) zvinofanirwa kugadziriswa organically kuti ive nechokwadi chekuti cleansing solution kana plasma source gas inogona kuyerera ichidzika pasi pemugero. Shanduko diki mu variable inoda kuverengerwazve kwezvimwe zvinoshanduka, uye iyi recalculation process inodzokororwa kusvika yasangana nechinangwa chedanho rega rega. Munguva pfupi yapfuura, monoatomic layers dzakadai seatomic layer deposition (ALD) layers dzave dzakatetepa uye dzakaoma. Nokudaro, tekinoroji yekucheka iri kufambira mberi pakushandisa tembiricha yakaderera uye kumanikidzwa. Maitiro ekucheka ane chinangwa chekudzora critical dimension (CD) kuti igadzire mapatani akanaka uye kuve nechokwadi chekuti matambudziko anokonzerwa nemaitiro ekucheka anodziviswa, kunyanya pasi pekucheka uye matambudziko ane chekuita nekubvisa masara. Nyaya mbiri dziri pamusoro apa pamusoro pekucheka dzine chinangwa chekupa vaverengi kunzwisisa chinangwa chekucheka, zvipingamupinyi zvekuzadzisa zvinangwa zviri pamusoro apa, uye zviratidzo zvekushanda zvinoshandiswa kukunda zvipingamupinyi zvakadaro.
Nguva yekutumira: Gunyana-10-2024