US4849071A
Expired / Lapsed
US
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Method of forming a sealed 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 forming a sealed diaphragm (3) on a substrate (1) which comprises providing on the substrate (1) a sacrificial layer (2) , providing a diaphragm layer (3) over the sacrificial layer (2), providing at least one aperture (5) in the diaphragm layer (3) which is spaced from the periphery of the diaphragm layer (3), at least partially removing the sacrificial layer (2) from between the substrate (1) and the diaphragm layer (3) by way of the at least one aperture (5) and closing the at least one aperture (5).
Inventors
- 👤 Alan G. R. Evans
- 👤 Mohammed M. Farooqui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:58
CPC Classifications
H; H04; H04R; H04R19/00; G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; G01L9/0072; G01L9/0073; H04R7/00; H04R7/02; Y; Y10; Y10S; Y10S438/00; Y10S438/98; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49103
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
121 words
A method of forming a sealed diaphragm on a substrate comprising the steps of: (a) providing on the substrate a sacrificial layer; (b) providing a diaphragm layer over said sacrificial layer, said diaphragm layer being formed from an electrically conducting material which can be converted to a dielectric; (c) providing at least one aperture in said diaphragm layer which is spaced from the periphery of the diaphragm layer; (d) at least partially removing said sacrificial layer from between said substrate and said diaphragm layer by way of said at least one aperture, (e) closing said at least one aperture, and (f) providing a mask over a part of said diaphragm and converting the unmasked part of the diaphragm to a dielectric.
Claim 2
Independent Claim
121 words
A method of forming a sealed diaphragm on a substrate comprising the steps of: (a) providing on the substrate a sacrificial layer; (b) providing a diaphragm layer over said sacrificial layer, said diaphragm layer being formed from an electrically conducting material which can be converted to a dielectric; (c) providing at least one aperture in said diaphragm layer which is spaced from the periphery of the diaphragm layer; (d) at least partially removing said sacrificial layer from between said substrate and said diaphragm layer by way of said at least one aperture, (e) closing said at least one aperture, and (f) providing a mask over a part of said diaphragm and converting the unmasked part of the diaphragm to a dielectric.
Claim 3
Dependent Claim
13 words
A method according to claim 1, wherein said substrate is a silicon substrate.
Claim 4
Dependent Claim
15 words
A method according to claim 2, wherein said sacrificial layer is formed from silicon dioxide.
Claim 5
Dependent Claim
14 words
A method according to claim 3, wherein said diaphragm layer is formed from polysilicon.
Claim 6
Dependent Claim
17 words
A method according to claim 4, wherein said sacrificial layer is deposited or grown on the substrate.
Claim 7
Dependent Claim
20 words
A method according to claim 5, wherein said deposited or grown sacrificial layer is patterned to the predetermined diaphragm configuration.
Claim 8
Dependent Claim
21 words
A method according to claim 6, wherein said diaphragm layer overlaps said sacrificial layer at all points around the periphery thereof.
Claim 9
Dependent Claim
16 words
A method according to claim 7, wherein the diaphragm layer is deposited over the sacrificial layer.
Claim 10
Dependent Claim
17 words
A method according to claim 8, wherein the deposited diaphragm layer is patterned to the predetermined shape.
Claim 11
Dependent Claim
48 words
A method according to claim 9, wherein said at least one aperture is formed in the diaphragm layer by photoetching, laser drilling, electro erosion, microalloying and etching, locally oxidizing or by forming a protrusion on the sacrificial layer, forming the diaphragm layer and planarization to remove said protrusion.
Claim 12
Dependent Claim
25 words
A method according to claim 10, wherein said sacrificial layer is at least partially removed from between the substrate and the diaphragm layer by etching.
Claim 13
Dependent Claim
14 words
A method according to claim 11, wherein hydrogen fluoride is used as the etchant.
Claim 14
Dependent Claim
27 words
A method according to claim 12, wherein said at least one aperture is closed by depositing a sealing material in said aperture or over said diaphragm layer.
Claim 15
Dependent Claim
17 words
A method according to claim 13, wherein silicon dioxide is deposited in said at least one aperture.
Claim 16
Dependent Claim
23 words
A method according to claim 14, wherein the diaphragm layer is chemically or thermally treated to impart predetermined electrical or physical properties thereto.
Claim 17
Dependent Claim
31 words
A method according to claim 15, wherein said mask is provided over a central diaphragm area of said diaphragm and the peripheral margin of the diaphragm is converted to a dielectric.
Claim 18
Dependent Claim
42 words
A method according to claim 16, wherein a silicon nitride mask is deposited on said diaphragm and patterned to mask a predetermined part of the diaphragm and the unmasked part of the diaphragm is then oxidized to convert it to silicon dioxide.
Claim 19
Dependent Claim
27 words
A method according to claim 17, wherein electric connecting tracks are provided by metallizing the diaphragm and etching away the unwanted metal to leave the connecting tracks.
Claim 20
Dependent Claim
18 words
A method according to claim 18, which comprises simultaneously forming a plurality of diaphragms on a single substrate.
Claim 21
Dependent Claim
15 words
A method according to claim 1, wherein said sacrificial layer is formed from silicon dioxide.
Claim 22
Dependent Claim
14 words
A method according to claim 1, wherein said diaphragm layer is formed from polysilicon.
Claim 23
Dependent Claim
17 words
A method according to claim 1, wherein said sacrificial layer is deposited or grown on the substrate.
Claim 24
Dependent Claim
20 words
A method according to claim 22, wherein said deposited or grown sacrificial layer is patterned to the predetermined diaphragm configuration.
Claim 25
Dependent Claim
21 words
A method according to claim 1, wherein said diaphragm layer overlaps said sacrificial layer at all points around the periphery thereof.
Claim 26
Dependent Claim
27 words
A method according to claim 1 wherein the diaphragm layer is deposited over the sacrificial layer and the deposited diaphragm layer is patterned to the required shape.
Claim 27
Dependent Claim
48 words
A method according to claim 1, wherein said at least one aperture is formed in the diaphragm layer by photoetching, laser drilling, electro erosion, microalloying and etching, locally oxidizing or by forming a protrusion on the sacrificial layer, forming the diaphragm layer and planarization to remove said protrusion.
Claim 28
Dependent Claim
25 words
A method according to claim 1, wherein said sacrificial layer is at least partially removed from between the substrate and the diaphragm layer by etching.
Claim 29
Dependent Claim
27 words
A method according to claim 1, wherein said at least one aperture is closed by depositing a sealing material in said aperture or over said diaphragm layer.
Claim 30
Dependent Claim
22 words
A method according to claim 1, wherein silicon dioxide is deposited in said at least one aperture sufficiently to close said aperture.
Claim 31
Dependent Claim
31 words
A method according to claim 1, wherein said mask is provided over a central diaphragm area of said diaphragm and the peripheral margin of the diaphragm is converted to a dielectric.
Claim 32
Dependent Claim
49 words
A method according to claim 1, wherein said diaphragm layer is formed from polysilicon, a silicon nitride mask is deposited on said diaphragm and patterned to mask a predetermined part of the diaphragm and the unmasked part of the diaphragm is then oxidized to convert it to silicon dioxide.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 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 |