Patent US4849050A successfully refreshed from Google Patents.
US4849050A
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Method of producing a diaphragm on a substrate
Assignee: Hamilton Standard Controls Inc
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Filing: 1987-12-09
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Granted: 1989-07-18
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Expires: 2007-12-09
Abstract
Abstract The invention provides a method of producing on a substrate a diaphragm which is electrically isolated from the substrate. The method comprises obtaining a substrate (2) having a diaphragm(1) thereon which comprises a flexible central portion (1a) and a shouldered peripheral portion which supports the central portion (1a) above the substrate (2), applying a mask (6) over at least a part of the central portion (1a) and converting the unmasked portion (1b) of the diaphragm to a dielectric so as to electrically isolate the masked central portion (1a) of the diaphragm from the substrate (2).
Inventors
- 👤 Alan G. R. Evans
- 👤 Mohammed M. Farooqui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:06
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0072; G01L9/0073; H; H04; H04R; H04R19/00; H04R7/00; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49103
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
95 words
A method of producing on a substrate a diaphragm which is electrically isolated from the substrate, comprising the steps of: (a) obtaining a substrate having thereon a diaphragm comprising a flexible central portion and a shouldered peripheral portion which supports the central portion above the substrate, the diaphragm being formed from a material which is convertible to a dielectric; (b) applying a mask over at least a part of said central portion, and (c) converting the unmasked portion of the diaphragm to a dielectric, whereby to electrically isolate said masked central portion from the substrate.
Claim 2
Independent Claim
95 words
A method of producing on a substrate a diaphragm which is electrically isolated from the substrate, comprising the steps of: (a) obtaining a substrate having thereon a diaphragm comprising a flexible central portion and a shouldered peripheral portion which supports the central portion above the substrate, the diaphragm being formed from a material which is convertible to a dielectric; (b) applying a mask over at least a part of said central portion, and (c) converting the unmasked portion of the diaphragm to a dielectric, whereby to electrically isolate said masked central portion from the substrate.
Claim 3
Dependent Claim
65 words
A method according to claim 1, wherein the diaphragm is formed on said substrate by providing on said substrate a sacrificial layer having at least one arm extending outwardly therefrom, providing a diaphragm layer over said sacrificial layer so that the diaphragm layer overlaps the periphery of said sacrificial layer except in the region of said at least one arm, and removing said sacrificial layer.
Claim 4
Dependent Claim
32 words
A method according to claim 2, wherein said sacrificial layer is deposited on said substrate, said diaphragm layer is deposited over said sacrificial layer and said sacrificial layer is removed by etching.
Claim 5
Dependent Claim
22 words
A method according to claim 2, which comprises sealing with a dielectric material the gap left by said at least one arm.
Claim 6
Dependent Claim
32 words
A method according to claim 4, wherein said sacrificial layer is deposited on said substrate, said diaphragm layer is deposited over said sacrificial layer and said sacrificial layer is removed by etching.
Claim 7
Dependent Claim
27 words
A method according to claim 5, wherein silicon dioxide is provided around the periphery of the diaphragm to provide a seal between the diaphragm and the substrate.
Claim 8
Dependent Claim
19 words
A method according to claim 5, wherein the unmasked portion of the diaphragm is chemically converted to a dielectric.
Claim 9
Dependent Claim
38 words
A method according to claim 7, wherein said substrate is formed from silicon, said diaphragm is formed from polysilicon, said mask is formed from silicon nitride and the unmasked portion of the diaphragm is converted to silicon dioxide.
Claim 10
Dependent Claim
26 words
A method according to claim 8, wherein the unmasked portion of the diaphragm is oxididized in an oxidizing atmosphere to convert the polysilicon to silicon dioxide.
Claim 11
Dependent Claim
27 words
A method according to claim 9, wherein oxidizing of the unmasked portion of the polysilicon diaphragm is carried out at elevated temperature of 1000° C. or more.
Claim 12
Dependent Claim
27 words
A method according to claim 10, wherein silicon dioxide is provided around the periphery of the diaphragm to provide a seal between the diaphragm and the substrate.
Claim 13
Dependent Claim
23 words
A method according to claim 11, wherein the central portion of the diaphragm is treated to impart predetermined electrical or physical properties thereto.
Claim 14
Dependent Claim
24 words
A method according to claim 12, wherein said mask is removed after the unmasked portion of the diaphragm has been converted to a dielectric.
Claim 15
Dependent Claim
19 words
A method according to claim 1, wherein the unmasked portion of the diaphragm is chemically converted to a dielectric.
Claim 16
Dependent Claim
38 words
A method according to claim 1, wherein said substrate is formed from silicon, said diaphragm is formed from polysilicon, said mask is formed from silicon nitride and the unmasked portion of the diaphragm is converted to silicon dioxide.
Claim 17
Dependent Claim
26 words
A method according to claim 15, wherein the unmasked portion of the diaphragm is oxidized in an oxidizing atmosphere to convert the polysilicon to silicon dioxide.
Claim 18
Dependent Claim
27 words
A method according to claim 16, wherein oxidizing of the unmasked portion of the polysilicon diaphragm is carried out at elevated temperature of 1000° C. or more.
Claim 19
Dependent Claim
27 words
A method according to claim 1 wherein silicon dioxide is provided around the periphery of the diaphragm to provide a seal between the diaphragm and the substrate.
Claim 20
Dependent Claim
23 words
A method according to claim 1, wherein the central portion of the diaphragm is treated to impart predetermined electrical or physical properties thereto.
Claim 21
Dependent Claim
24 words
A method according to claim 1, wherein said mask is remove after the unmasked portion of the diaphragm has been converted to a dielectric.
References Cited (Backward Citations)
JPS5878471A
Cited
US4592238A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |