Kunyorova kwekutanga kwakasimudzira kuvandudzwa kwekuchenesa kana kuita madota. Nhasi, yakaoma etching uchishandisa plasma ndiyo yave iyo huruetching process. Plasma ine maerekitironi, cations uye radicals. Simba rinoshandiswa paplasma rinoita kuti maerekitironi ekunze egasi ari munzvimbo isina kwaakarerekera abviswe, zvichibva zvashandura maerekitironi aya kuita makesheni.
Pamusoro pezvo, maatomu asina kukwana mumamorekuru anogona kubviswa nekushandisa simba kugadzira magetsi asina kwaarerekera. Dry etching inoshandisa cations uye radicals inoumba plasma, uko cations ari anisotropic (yakakodzera etching mune imwe nzira) uye radicals isotropic (yakakodzera etching kumativi ese). Huwandu hwema radicals hwakakura kwazvo kupfuura huwandu hwemakesheni. Mune ino kesi, yakaoma etching inofanirwa kuve isotropic senge yakanyorova etching.
Nekudaro, iyo anisotropic etching yekuoma etching inoita kuti ultra-miniaturized maseketi agoneke. Chii chiri chikonzero cheizvi? Uye zvakare, iyo etching kumhanya kwema cations uye radicals inononoka kwazvo. Saka isu tingashandise sei nzira dzeplasma etching pakugadzirwa kwakawanda pamberi pekushomeka uku?
1. Chiyero chechikamu (A/R)
Mufananidzo 1. Pfungwa yehuwandu hwehuwandu uye kukanganisa kwekufambira mberi kwetekinoroji pairi
Aspect Ratio ireshiyo yehupamhi hwakachinjika kuenda kuhurefu hwakatwasuka (kureva, urefu hwakakamurwa nehupamhi). Iyo diki iyo yakakosha dimension (CD) yedunhu, iyo yakakura iyo aspect ratio kukosha. Kureva kuti, tichitora aspect ratio kukosha kwegumi uye hupamhi hwe10nm, kureba kwegomba rakaboorwa panguva yekumisikidza kunofanirwa kuve 100nm. Naizvozvo, kune chinotevera-chigadzirwa zvigadzirwa zvinoda Ultra-miniaturization (2D) kana yakakwirira density (3D), yakanyanya kukwirira chimiro chechiyero inodiwa kuti ive nechokwadi chekuti cations inogona kupinda mufirimu rezasi panguva yekucheka.
Kuti uwane tekinoroji yekupedzisira-miniaturization ine chiyero chakakosha cheisingasviki 10nm mune zvigadzirwa zve2D, iyo capacitor aspect ratio kukosha kweiyo dynamic random access memory (DRAM) inofanirwa kuchengetedzwa pamusoro pe100. Saizvozvo, 3D NAND flash memory inodawo yakakwirira chikamu cheyeroshi. kurongedza 256 layers kana kupfuura ye cell stacking layer. Kunyangwe kana mamiriro anodiwa kune mamwe maitiro akazadzikiswa, zvigadzirwa zvinodiwa hazvigone kugadzirwa kana iyoetching processhaisi kusvika pachiyero. Ichi ndicho chikonzero etching tekinoroji iri kuwedzera kukosha.
2. Pfupiso ye plasma etching
Mufananidzo 2. Kusarudza plasma source gasi maererano nemhando yefirimu
Kana pombi isina mhango inoshandiswa, iyo yakatetepa dhayamita yepombi, zviri nyore kuti mvura ipinde, iyo inonzi inonzi capillary phenomenon. Zvisinei, kana gomba (rakavharwa kupera) richizoboorwa munzvimbo yakashama, kupinza kwemvura kunova kwakaoma. Naizvozvo, sezvo saizi yakakosha yedunhu yaive 3um kusvika 5um pakati pemakore ekuma1970, yakaoma.etchingzvishoma nezvishoma yakatsiva wet etching seyakanyanya. Kureva kuti, kunyangwe ionized, zviri nyore kupinda mumakomba akadzika nekuti vhoriyamu yemorekuru imwe idiki pane iyo yeorganic polymer solution molecule.
Munguva yePlasma etching, iyo yemukati yekamuri yekugadziridza inoshandiswa kune etching inofanirwa kugadziridzwa kune vacuum state isati yabaya plasma sosi gasi rakakodzera kune rakakodzera layer. Paunenge uchiisa yakasimba oxide mafirimu, yakasimba kabhoni fluoride-yakavakirwa sosi magasi anofanirwa kushandiswa. Kune isina kusimba silicon kana simbi mafirimu, chlorine-based plasma sosi magasi anofanirwa kushandiswa.
Saka, iyo gedhi layer uye iri pasi pesilicon dioxide (SiO2) insulating layer inofanira kuiswa sei?
Kutanga, kune gedhi layer, silicon inofanira kubviswa uchishandisa chlorine-based plasma (silicon + chlorine) ine polysilicon etching selectivity. Kune yepasi insulating layer, iyo silicon dioxide firimu inofanirwa kuiswa mumatanho maviri uchishandisa kabhoni fluoride-based plasma source gasi (silicon dioxide + carbon tetrafluoride) ine yakasimba etching selectivity uye inoshanda.
3. Reactive ion etching (RIE kana physicochemical etching) maitiro
Mufananidzo 3. Zvakanakira reactive ion etching (anisotropy uye yakakwirira etching rate)
Plasma ine ese ari maviri isotropic emahara radicals uye anisotropic cations, saka inoita sei anisotropic etching?
Plasma yakaoma etching inonyanya kuitwa neiyo reactive ion etching (RIE, Reactive Ion Etching) kana maapplication anoenderana neiyi nzira. Nheyo yeRIE nzira ndeyekunetesa simba rinosunga pakati pemamorekuru anonangwa mufirimu nekurwisa nzvimbo yekumisikidza ine anisotropic cations. Iyo nzvimbo isina simba inobatwa nemahara radicals, yakabatanidzwa nezvikamu zvinoumba iyo layer, inoshandurwa kuita gasi (inoputika komputa) uye yakaburitswa.
Kunyange zvazvo mahara radicals ane isotropic maitiro, mamorekuru anoumba pasi pasi (ayo anosunga simba akaderedzwa nekurwiswa kwema cations) anotorwa nyore nyore nemahara radicals uye anoshandurwa kuita makomisheni matsva pane madziro emativi ane simba rekusunga rakasimba. Naizvozvo, kudzika kwakadzika kunova chinhu chikuru. Izvo zvimedu zvakabatwa zvinova gasi nemahara radicals, ayo anobviswa uye anoburitswa kubva pamusoro pasi pechiito chevacuum.
Panguva ino, ma cations anowanikwa nekuita kwemuviri uye emahara radicals anowanikwa nekemikari chiito anosanganiswa kwemuviri uye makemikari etching, uye etching rate (Etch Rate, dhigirii rekucheka mune imwe nguva yenguva) inowedzerwa negumi nguva. zvichienzaniswa nenyaya yecationic etching kana mahara radical etching chete. Iyi nzira haigone chete kuwedzera etching rate yeanisotropic yakadzika etching, asi zvakare kugadzirisa dambudziko remapolymer asara mushure mekucheka. Iyi nzira inonzi reactive ion etching (RIE). Kiyi yekubudirira kweRIE etching ndeyekutsvaga plasma sosi gasi rakakodzera etching iyo firimu. Ongorora: Plasma etching ndeyeRIE etching, uye izvo zviviri zvinogona kutorwa sepfungwa imwechete.
4. Etch Rate uye Core Performance Index
Mufananidzo 4. Core Etch Performance Index yakabatana neEtch Rate
Etch rate inoreva kudzika kwefirimu rinotarisirwa kusvikwa muminiti imwe. Saka zvinorevei kuti chiyero che etch chinosiyana kubva kune chikamu kuenda kune chikamu pane imwechete wafer?
Izvi zvinoreva kuti kudzika kwe etch kunosiyana kubva kune chikamu kuenda kune chikamu pane wafer. Nechikonzero ichi, zvakakosha kwazvo kuseta iyo yekupedzisira poindi (EOP) apo etching inofanirwa kumira nekufunga avhareji etch rate uye etch kudzika. Kunyangwe iyo EOP ikaiswa, pachine dzimwe nzvimbo uko kudzika kwe etch kwakadzika (kupfuura-yakadzika) kana kudzika (pasi-etched) pane zvakarongwa pakutanga. Nekudaro, pasi-etching inokonzeresa kukuvadza kupfuura kuwedzeredza-etching panguva yekucheka. Nekuti kana iri nyaya ye under-etching, iyo under-etched part inotadzisa anotevera maitirwo akadai sekuiswa ion.
Zvichakadaro, selectivity (yakayerwa ne etch rate) chinhu chakakosha chekuita chiratidzo cheiyo etching maitiro. Chiyero chechiyero chakavakirwa pakuenzanisa kwe etch chiyero cheiyo mask layer (photoresist firimu, oxide firimu, silicon nitride firimu, nezvimwewo) uye yakanangwa layer. Izvi zvinoreva kuti iyo yakakwira iyo selectivity, iyo inokurumidza iyo inotarirwa layer inoiswa. Iyo yakakwira mwero weiyo miniaturization, iyo yakakwirira iyo inodiwa yekusarudza ndeyekuona kuti yakanaka mapatani anogona kuratidzwa zvakakwana. Sezvo iyo etching nzira yakatwasuka, kusarudzwa kwe cationic etching kwakadzikira, nepo kusarudzwa kweiyo radical etching kwakakwira, izvo zvinovandudza kusarudzwa kweRIE.
5. Etching process
Mufananidzo 5. Etching process
Chekutanga, wafer inoiswa muchoto cheoxidation ine tembiricha inochengetwa pakati pe800 ne1000 ℃, uyezve silicon dioxide (SiO2) firimu rine yakakwirira insulation zvimiro inoumbwa pamusoro pechifukidzo nenzira yakaoma. Tevere, iyo deposition process inopinzwa kuti igadzire silicon layer kana conductive layer pane oxide firimu nemakemikari vapor deposition (CVD)/physical vapor deposition (PVD). Kana iyo silicon layer ikaumbwa, kusachena kupararira maitiro kunogona kuitwa kuwedzera conductivity kana zvichidikanwa. Munguva yekusachena kwekupararira kwemaitiro, tsvina yakawanda inowanzowedzerwa kakawanda.
Panguva ino, iyo insulating layer uye iyo polysilicon layer inofanirwa kusanganiswa kuti iite etching. Kutanga, photoresist inoshandiswa. Zvadaro, chifukidzo chinoiswa pane photoresist firimu uye kunyorova kuratidzwa kunoitwa nekunyudzwa kuti adhinde yaidiwa pateni (isingaoneki neziso rakashama) pane photoresist firimu. Kana iyo pateni yakaratidzwa nebudiriro, iyo photoresist iri munzvimbo ine photosensitive inobviswa. Zvadaro, wafer yakagadziriswa nephotolithography process inoendeswa kune etching process yekuoma etching.
Dry etching inonyanya kuitiswa neiyo reactive ion etching (RIE), umo etching inodzokororwa zvakanyanya nekutsiva iyo sosi gasi rakakodzera firimu rega rega. Ese ari maviri etching etching uye kunyorova etching anovavarira kuwedzera chikamu chechiyero (A/R kukosha) kwe etching. Mukuwedzera, kuchenesa nguva dzose kunodiwa kuti ubvise iyo polymer yakaunganidzwa pazasi pegomba (iyo gap inogadzirwa ne etching). Chinhu chakakosha ndechekuti zvese zvinosiyana (senge zvinhu, sosi gasi, nguva, fomu uye kutevedzana) zvinofanirwa kugadziridzwa organic kuti ive nechokwadi chekuti mhinduro yekuchenesa kana plasma sosi gasi inogona kuyerera ichidzika pasi pegoronga. Kuchinja kudiki mukuchinja kunoda kuverengerwazve kwemamwe mabhii, uye iyi nzira yekuverengazve inodzokororwa kusvika yasangana nechinangwa chechikamu chimwe nechimwe. Munguva pfupi yapfuura, monoatomic layers senge atomic layer deposition (ALD) layers dzave dzakatetepa nekuoma. Naizvozvo, etching tekinoroji iri kufamba yakanangana nekushandiswa kweyakadzika tembiricha uye kumanikidza. Iyo etching process inovavarira kudzora yakakosha dimension (CD) kuburitsa yakanaka mapatani uye kuona kuti matambudziko anokonzerwa ne etching maitiro anodzivirirwa, kunyanya pasi-etching uye matambudziko ane chekuita nekubviswa kwemasara. Zvinyorwa zviviri zviri pamusoro apa nezve etching zvinovavarira kupa vaverengi kunzwisisa kwechinangwa cheiyo etching maitiro, zvipingamupinyi zvekuzadzisa zvinangwa zviri pamusoro, uye zviratidzo zvekuita zvinoshandiswa kukunda zvipingamupinyi zvakadaro.
Nguva yekutumira: Sep-10-2024