US5289721A
Expired / Lapsed
US
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Semiconductor pressure sensor
Assignee: Denso Corp
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Filing: 1991-09-09
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Granted: 1994-03-01
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Expires: 2011-09-09
Abstract
Abstract A semiconductor pressure sensor comprises a silicon substrate having a surface orientation of substantially (110), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate. The diaphragm has an octagonal shape whose sides are orthogonal to axis<100>, <110>, and<111>, respectively. This sensor causes substantially no output error and no fluctuation between output characteristics of the strain gauges irrespective of a change in temperature.
Inventors
- 👤 Yukihiko Tanizawa
- 👤 Hiroshi Okada
- 👤 Kazuhisa Ikeda
- 👤 Tsuyoshi Fukada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:19
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; G01L9/0051; G01L9/0052; G01L9/0054; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49103
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
67 words
A semiconductor pressure sensor comprising a silicon substrate having a surface orientation of substantially (110), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate, wherein the diaphragm is defined by a concave portion which is anisotropically etched in said substrate, a bottom portion of which having an octagonal shape whose sides are orthogonal to axis<100>,<110>, and<111>, respectively.
Claim 2
Dependent Claim
67 words
A semiconductor pressure sensor comprising a silicon substrate having a surface orientation of substantially (110), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate, wherein the diaphragm is defined by a concave portion which is anisotropically etched in said substrate, a bottom portion of which having an octagonal shape whose sides are orthogonal to axis<100>,<110>, and<111>, respectively.
Claim 3
Dependent Claim
18 words
A semiconductor pressure sensor according to claim 1, wherein the substrate and base have different thermal expansion coefficients.
Claim 4
Dependent Claim
27 words
A semiconductor pressure sensor according to claim 1, wherein the principal plane of the substrate has an off-angle of several degrees with respect to a plane (110).
Claim 5
Dependent Claim
23 words
A semiconductor pressure sensor according to claim 1, wherein the strain gauges disposed on the diaphragm are connected to form a bridge circuit.
Claim 6
Dependent Claim
40 words
A semiconductor pressure sensor according to claim 1, wherein the strain gauges are arranged symmetrically with respect to an axis<110>extending through the center of the diaphragm, such that longitudinal axis of the strain gauges are oriented parallel with the axis<110>.
Claim 7
Dependent Claim
62 words
A semiconductor pressure sensor according to claim 1, wherein the octagonal recessed shape of the diaphragm has a pair of first sides each having a length of l and a pair of parallel second sides spaced apart from each other by a distance L and extending approximately perpendicular to the first sides, wherein l/L is in a range of 0.25 to 0.65.
Claim 8
Dependent Claim
13 words
A semiconductor pressure sensor according to claim 6, wherein l/L is around 0.4.
Claim 9
Dependent Claim
17 words
A semiconductor pressure sensor according to claim 1, wherein the strain gauges are made of polysilicon resistors.
Claim 10
Dependent Claim
43 words
A semiconductor pressure sensor according to claim 1, wherein the substrate comprises a first substrate having a surface orientation of (110) and a second monocrystalline silicon substrate having a surface orientation of (100), the first and second substrates being joined with each other.
Claim 11
Dependent Claim
19 words
A pressure sensor as in claim 1 wherein said strain gauges are in a central portion of said diaphragm.
Claim 12
Dependent Claim
52 words
A pressure sensor as in claim 1 wherein said sides forming said octagonal shape include two parallel sides orthogonal to the<111> axis and substantially vertical to the bottom surface of the cavity, and the remaining sidewalls inclined by a certain number of degrees with respect to the bottom surface of the cavity.
Claim 13
Dependent Claim
102 words
A semiconductor pressure sensor comprising a silicon substrate having a surface orientation of substantially (100), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate, wherein the diaphragm has an octagonal recessed shape whose sides are orthogonal to axes<100>,<110>, and<111>, respectively, said octagonal recessed shape of the diaphragm including a pair of first sides each having a length of l and a pair of parallel second sides spaced apart from each other by a distance L and extending orthogonally to the first sides, wherein l/L is in a range of 0 to 0.5.
Claim 14
Dependent Claim
102 words
A semiconductor pressure sensor comprising a silicon substrate having a surface orientation of substantially (100), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate, wherein the diaphragm has an octagonal recessed shape whose sides are orthogonal to axes<100>,<110>, and<111>, respectively, said octagonal recessed shape of the diaphragm including a pair of first sides each having a length of l and a pair of parallel second sides spaced apart from each other by a distance L and extending orthogonally to the first sides, wherein l/L is in a range of 0 to 0.5.
Claim 15
Dependent Claim
52 words
A pressure sensor as in claim 12 wherein said sides forming said octagonal shape include two parallel sides orthogonal to the<111> axis and substantially vertical to the bottom surface of the cavity, and the remaining sidewalls inclined by a certain number of degrees with respect to the bottom surface of the cavity.
Claim 16
Dependent Claim
86 words
A semiconductor pressure sensor comprising an octagonal diaphragm formed by anisotropically etching a semiconductor substrate whose principal plane has a predetermined off-angle with respect to one of the (110) and (100) planes of the semiconductor substrate, a plurality of strain gauges symmetrically arranged on the diaphragm, and a base joined with the substrate, wherein a center of symmetry of the arrangement of strain gauges is at a same position as a center of the bottom of the diaphragm in a direction orthogonal to the principal plane.
Claim 17
Dependent Claim
86 words
A semiconductor pressure sensor comprising an octagonal diaphragm formed by anisotropically etching a semiconductor substrate whose principal plane has a predetermined off-angle with respect to one of the (110) and (100) planes of the semiconductor substrate, a plurality of strain gauges symmetrically arranged on the diaphragm, and a base joined with the substrate, wherein a center of symmetry of the arrangement of strain gauges is at a same position as a center of the bottom of the diaphragm in a direction orthogonal to the principal plane.
Claim 18
Dependent Claim
39 words
A semiconductor pressure sensor according to claim 14, wherein a polygonal shape formed on an etching start surface of the substrate is asymmetric when turned half a round, and the octagonal diaphragm is symmetric when turned half a round.
Claim 19
Dependent Claim
52 words
A pressure sensor as in claim 14 wherein said sides forming said octagonal shape include two parallel sides orthogonal to the<111> axis and substantially vertical to the bottom surface of the cavity, and the remaining sidewalls inclined by a certain number of degrees with respect to the bottom surface of the cavity.
References Cited (Backward Citations)
JPS6013314B2
Cited
US4691575A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-28 | 1997-08-30 | 1998-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-28 | 2001-08-30 | 2002-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-28 | 2005-08-30 | 2006-03-01 | $7700.00 | Window Closed / Lapsed |