Batch fabricated semiconductor thin-film pressure sensor and method of making same
US6700174B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 1997 |
| Grant date | Mar 2, 2004 |
| Priority date | — |
| Expiry date | Jul 31, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2224/48091
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pressure sensor having a flexible membrane which is moved by an external force, such as pressure from an air flow. The flexible membrane extends over a semiconductor frame having an opening, such that a portion of the flexible membrane extends over the semiconductor frame, and a portion of the flexible membrane extends over the opening. An inherent tensile stress is present in the membrane. One or more strain gage resistors are formed on the portion of the membrane which extends over the opening of the semiconductor frame. The membrane deforms in response to an externally applied pressure. As the membrane deforms, the strain gage resistors elongate, thereby increasing the resistances of these resistors. This change in resistance is measured and used to determine the magnitude of the external pressure. In one embodiment, a Wheatstone bridge circuit is used to translate the change in resistance of the strain gage resistors into a differential voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.