Removing sacrificial material through temporary channels as a method of making an overpressure-protected differential pressure sensor
US5438875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1994 |
| Grant date | Aug 8, 1995 |
| Priority date | — |
| Expiry date | Apr 21, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49996
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An overpressure-protected, differential pressure sensor 37 is formed by depositing diaphragm material 24 over a cavity 23 formed and filled with sacrificial material 22 into a front surface of a substrate. The sacrificial material 22 is then removed to create a free diaphragm. The floor of the cavity 23 defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port 33 is created to allow pressure to be applied to the bottom side of the diaphragm 24. An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap 35 to standoffs 34 placed around the top of the diaphragm. The standoffs are spaced to allow pressure to be applied to the top of the diaphragm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.