Selective plasma etching of silicon oxide relative to silicon nitride by gas pulsing
US11158517B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2020 |
| Grant date | Oct 26, 2021 |
| Priority date | — |
| Expiry date | Jan 10, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for selective plasma etching of silicon oxide relative to silicon nitride. The method includes a) providing a substrate containing a silicon oxide film and a silicon nitride film, b) exposing the substrate to a plasma-excited treatment gas containing 1) H2 and 2) HF, F2, or both HF and F2, to form a silicon oxide surface layer with reduced oxygen content on the silicon oxide film and form an ammonium salt layer on the silicon nitride film, c) exposing the substrate to a plasma-excited halogen-containing gas that reacts with and removes the silicon oxide surface layer from the silicon oxide film, and d) repeating steps b) and c) at least once to further selectively etch the silicon oxide film relative to the ammonium salt layer on the silicon nitride film. The ammonium salt layer may be removed when the desired etching has been achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.