Robust micromachined thermal mass flow sensor with double side passivated polyimide membrane
US8132455B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Aug 10, 2009 |
| Grant date | Mar 13, 2012 |
| Priority date | — |
| Expiry date | Dec 28, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/692
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A micromachined thermal mass flow sensor comprises a high mechanical strength polyimide film as a supporting layer of suspending membrane. The polyimide film provides superior thermal insulating properties to reduce the power consumption of device. Due to the tendency of humidity absorption, the polyimide suspending membrane is double side passivated on both top and bottom surfaces to sustain its long term stability from rush and humid working environment. A thin layer of silicon dioxide deposited by plasma enhanced chemical vapor deposition is overlaid between the silicon nitride and polyimide film to enhance the adhesion property of passivation layers to polyimide surface. With such embodiments, a sturdy and robust micromachined thermal mass flow sensor with high measurement accuracy could be formed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.