Media-compatible electrically isolated pressure sensor for high temperature applications
US7775119B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 2009 |
| Grant date | Aug 17, 2010 |
| Priority date | — |
| Expiry date | Mar 3, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49165
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pressure sensor is described with sensing elements electrically and physically isolated from a pressurized medium. An absolute pressure sensor has a reference cavity, which can be at a vacuum or zero pressure, enclosing the sensing elements. The reference cavity is formed by bonding a recessed cap wafer with a gauge wafer having a micromachined diaphragm. Sensing elements are disposed on a first side of the diaphragm. The pressurized medium accesses a second side of the diaphragm opposite to the first side where the sensing elements are disposed. A spacer wafer may be used for structural support and stress relief of the gauge wafer. In one embodiment, vertical through-wafer conductive vias are used to bring out electrical connections from the sensing elements to outside the reference cavity. In an alternative embodiment, peripheral bond pads on the gauge wafer are used to bring out electrical connections from the sensing elements to outside the reference cavity. In various embodiments, a regular silicon-on-insulator wafer or a double silicon-on-insulator wafer may be used as the gauge wafer, and appropriate micromachining steps are adopted to define the diaphragm. A layer of corr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.