Method to improve profile control during selective etching of silicon nitride spacers
US10629451B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 2019 |
| Grant date | Apr 21, 2020 |
| Priority date | — |
| Expiry date | Feb 1, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/015
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Cyclic etch methods comprise the steps of: i) exposing a SiN layer covering a structure on a substrate in a reaction chamber to a plasma of hydrofluorocarbon (HFC) to form a polymer layer deposited on the SiN layer that modifies the surface of the SiN layer, the HFC having a formula CxHyFz where x=2-5, y>z, the HFC being a saturated or unsaturated, linear or cyclic HFC; ii) exposing the polymer layer deposited on the SiN layer to a plasma of an inert gas, the plasma of the inert gas removing the polymer layer deposited on the SiN layer and the modified surface of the SiN layer on an etch front; and iii) repeating the steps of i) and ii) until the SiN layer on the etch front is selectively removed, thereby forming a substantially vertically straight SiN spacer comprising the SiN layer on the sidewall of the structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.