US4443293A
Expired / Lapsed
US
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Method of fabricating transducer structure employing vertically walled diaphragms with quasi rectangular active areas
Assignee: Kulite Semiconductor Products Inc
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Filing: 1982-07-19
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Granted: 1984-04-17
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Expires: 2002-07-19
Abstract
Abstract There is disclosed a rectangular diaphragm employing a quasi rectangular active area. The diaphragm as configured has an aspect ratio which is the length to width ratio of greater than 3:1. The active area of the diaphragm, which is the area which most readily deflects upon application of a force to the diaphragm, is formed by an anisotropic etching technique to provide steep vertical sidewalls. The diaphragm structure thus described exhibits as a response to an applied force or pressure, a maximum longitudinal stress and a minimum transverse stress and can accommodate piezoresistive elements located within the active area of the diaphragm.
Inventors
- 👤 Joseph R. Mallon
- 👤 Anthony D. Kurtz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:49
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; G01L9/0051; G01L9/0052; G01L9/0054
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
62 words
A method of fabricating a diaphragm having a rectangular recess defining an active area comprising the steps of: (a) masking a major surface of a rectangular wafer of single crystal semiconductor of a given crystallographic orientation with a rectangular pattern; (b) anisotropically etching said pattern according to said orientation to provide a rectangular recess having steep sidewalls manifesting an active diaphragm area.
Claim 2
Independent Claim
62 words
A method of fabricating a diaphragm having a rectangular recess defining an active area comprising the steps of: (a) masking a major surface of a rectangular wafer of single crystal semiconductor of a given crystallographic orientation with a rectangular pattern; (b) anisotropically etching said pattern according to said orientation to provide a rectangular recess having steep sidewalls manifesting an active diaphragm area.
Claim 3
Dependent Claim
17 words
The method according to claim 1 wherein said wafer is single crystal silicon of (110) crysttallographic orientation.
Claim 4
Dependent Claim
19 words
The method according to claim 1 wherein said anisotropic etching employs a mixture of pyrocatechol, ethylene diamine and water.
Claim 5
Dependent Claim
27 words
The method according to claim 1 including the step of growing a layer of silicon oxide or nitride on said major surface prior to masking the same.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-17 | 1987-10-17 | 1988-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-17 | 1991-10-17 | 1992-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-17 | 1995-10-17 | 1996-04-17 | $7700.00 | Window Closed / Lapsed |