Independent control of etching and passivation gas components for highly selective silicon oxide/silicon nitride etching
US11024508B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 2020 |
| Grant date | Jun 1, 2021 |
| Priority date | — |
| Expiry date | Mar 24, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for selective plasma etching of silicon oxide relative to silicon nitride is described. The method includes providing a substrate containing a silicon oxide film and a silicon nitride film, and selectively etching the silicon oxide film relative to the silicon nitride film by: a1) exposing the substrate to a plasma-excited passivation gas containing carbon, sulfur, or both carbon and sulfur, where the plasma-excited passivation gas does not contain fluorine or hydrogen, and b1) exposing the substrate to a plasma-excited etching gas containing a fluorine-containing gas. The method can further include, between a1) and b1), an additional step of a2) exposing the substrate to a plasma-excited additional passivation gas containing a fluorocarbon gas, hydrofluorocarbon gas, a hydrochlorocarbon gas, a hydrochlorofluorocarbon gas, or a hydrocarbon gas, or a combination thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.