Method and apparatus for anisotropic tungsten etching
US10354888B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 2017 |
| Grant date | Jul 16, 2019 |
| Priority date | — |
| Expiry date | Mar 20, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/334
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Methods for anisotropically etching a tungsten-containing material (such as doped or undoped tungsten metal) include cyclic treatment of tungsten surface with Cl2 plasma and with oxygen-containing radicals. Treatment with chlorine plasma is performed while the substrate is electrically biased resulting in predominant etching of horizontal surfaces on the substrate. Treatment with oxygen-containing radicals passivates the surface of the substrate to etching, and protects the vertical surfaces of the substrate, such as sidewalls of recessed features, from etching. Treatment with Cl2 plasma and with oxygen-containing radicals can be repeated in order to remove a desired amount of material. Anisotropic etching can be performed selectively in a presence of dielectric materials such as silicon oxide, silicon nitride, and silicon oxynitride.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.