Micromachined integrated pressure sensor with oxide polysilicon cavity sealing
US5531121A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 1995 |
| Grant date | Jul 2, 1996 |
| Priority date | — |
| Expiry date | Jan 19, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P2015/0828
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is disclosed for micromachining the surface of a silicon substrate which encompasses a minimal number of processing steps. The method involves a preferential etching process in which a chlorine plasma etch is capable of laterally etching an N+ buried layer beneath the surface of the bulk substrate. Such a method is particularly suitable for forming sensing devices which include a small micromachined element, such as a bridge, cantilevered beam, membrane, suspended mass or capacitive element, which is supported over a cavity formed in a bulk silicon substrate. The method also permits the formation of such sensing devices on the same substrate as their controlling integrated circuits. This invention also provides novel methods by which such structures can be improved, such as through optimizing the dimensional characteristics of the micromachined element or by encapsulating the micromachined element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.