Small gauge pressure sensor using wafer bonding and electrochemical etch stopping
US7493822B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 2007 |
| Grant date | Feb 24, 2009 |
| Priority date | — |
| Expiry date | Jul 5, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/0054
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A gauge pressure sensor apparatus and a method of forming the same. A constraint wafer can be partially etched to set the diaphragm size, followed by bonding to a top wafer. The thickness of the top wafer is either the desired diaphragm thickness or is thinned to the desired thickness after bonding. The bonding of top wafer and constraint wafer enables electrochemical etch stopping. This allows the media conduit to be etched through the back of the constraint wafer and an electrical signal produced when the etching reaches the diaphragm. The process prevents the diaphragm from being over-etched. The invention allows the die size to be smaller than die where the diaphragm size is set by etching from the back side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.