Method of etching a cavity in a stack of layers
US10770306B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 4, 2019 |
| Grant date | Sep 8, 2020 |
| Priority date | — |
| Expiry date | Jan 4, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/42
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A cavity is etched in a stack of layers which includes a first layer made of a first material and a second layer made of a second material. To etch the cavity, a first etch mask having a first opening is formed over the stack of layer. The stack of layers is then etched through the first opening to a depth located in the second layer. A second mask having a second opening, the dimensions of which are smaller, in top view, than the first opening, is formed over the stack of layer. The second opening is located, in top view, opposite the area etched through the first opening. The second layer is then etched through the second opening to reach the first layer. The etch method used is configured to etch the second material selectively over the first material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.