Patent US5006487A successfully refreshed from Google Patents.
US5006487A
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Method of making an electrostatic silicon accelerometer
Assignee: Honeywell Inc
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Filing: 1990-03-27
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Granted: 1991-04-09
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Expires: 2010-03-27
Abstract
Abstract A solid state accelerometer having an all silicon sensor for measuring accelerational and gravitational forces. The accelerometer measuring system also has associated electronics that include an analog rebalance loop and a digitizer loop.
Inventors
- 👤 John F. Stokes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:17
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/0802; G01P15/125; G01P15/13; G01P15/131; G01P2015/0805; G01P2015/0822; G01P2015/0825; G01P2015/0828; Y; Y10; Y10S; Y10S148/00; Y10S148/012; Y10S438/00; Y10S438/914; Y10S438/924
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
178 words
A method for making a solid state accelerometer, comprising: depositing a p+ doped layer of epitaxial silicon on a double-sided polished first p- doped silicon wafer; dry etching a first pattern on the epitaxial silicon to define flexures and a proof mass; fusion bonding a second p- doped silicon wafer to the p+ doped layer of epitaxial silicon; thermally oxidizing the exposed surfaces of said first and second p- doped silicon wafers to grow dielectric interlayers to set widths of gaps for the proof mass; applying an etch resistant material of a second pattern the dielectric interlayers; anisotropically etching the first and second p- doped wafers to make individual flexures and the proof mass; removing inner portions of the dielectric interlayers to make the gaps; and fusion bonding first and second p+ doped silicon stop wafers to the dielectric interlayers of the first and second p- doped silicon wafers, thereby constituting the gaps between the proof mass and the first and second p+doped silicon stop wafers, and sealing the proof mass from volume external to the proof mass.
Claim 2
Independent Claim
178 words
A method for making a solid state accelerometer, comprising: depositing a p+ doped layer of epitaxial silicon on a double-sided polished first p- doped silicon wafer; dry etching a first pattern on the epitaxial silicon to define flexures and a proof mass; fusion bonding a second p- doped silicon wafer to the p+ doped layer of epitaxial silicon; thermally oxidizing the exposed surfaces of said first and second p- doped silicon wafers to grow dielectric interlayers to set widths of gaps for the proof mass; applying an etch resistant material of a second pattern the dielectric interlayers; anisotropically etching the first and second p- doped wafers to make individual flexures and the proof mass; removing inner portions of the dielectric interlayers to make the gaps; and fusion bonding first and second p+ doped silicon stop wafers to the dielectric interlayers of the first and second p- doped silicon wafers, thereby constituting the gaps between the proof mass and the first and second p+doped silicon stop wafers, and sealing the proof mass from volume external to the proof mass.
Claim 3
Dependent Claim
89 words
The method of claim 1 further comprising connecting associated electronics to the first and second p+ wafers and to the epitaxial layer, for measuring accelerational or gravitational forces via capacitances of the gaps which are varied by the accelerational or gravitational forces affecting the proof mass, for applying voltages across the proof mass and the first and second p+ doped silicon wafers to counteract with electrostatic forces the accelerational or gravitational forces affecting the proof mass, and for providing indications of the magnitudes of the accelerational or gravitational forces.
Claim 4
Dependent Claim
16 words
The method of claim 2 wherein the dielectric interlayers are SiO 2 and SiN 3 .
Claim 5
Dependent Claim
12 words
The method of claim 3 wherein the proof mass is a diaphragm.
Claim 6
Dependent Claim
12 words
The method of claim 3 wherein the proof mass is a pendulum.
References Cited (Backward Citations)
US4103273A
Cited
US3909924A
Cited
US4483194A
Cited
US4891985A
Cited
US4851080A
Cited
US4882933A
Cited
US4928203A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-08 | 1994-10-08 | 1995-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-08 | 1998-10-08 | 1999-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-08 | 2002-10-08 | 2003-04-09 | $7700.00 | Window Closed / Lapsed |