Method of fabricating microphone device and thermal oxide layer and low-stress structural layer thereof
US7456043B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2006 |
| Grant date | Nov 25, 2008 |
| Priority date | — |
| Expiry date | Mar 17, 2027 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB81B2201/0257
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A substrate is provided and a plurality of trenches are formed in the front surface of the substrate. Then, a thermal oxide layer is formed on inner walls of the trenches and the front surface of the substrate. Subsequently, a first structural layer is formed on the thermal oxide layer, dopants are implanted into the first structural layer, a second structural layer is formed on the first structural layer, and an annealing process is performed to reduce the stress of the first and second structural layers. Following that, the first and second structural layers are patterned to form diaphragms. Finally, the second structural layer is mounted on a support wafer with a bonding layer, and the back surface of the substrate is etched by deep etching techniques to form back chambers corresponding to the diaphragms. Each back chamber has a vertical sidewall and partially exposes the first structural layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.