US4764244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resonant sensor and method of making same
Assignee: Schneider Electric Systems USA Inc
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Filing: 1985-06-11
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Granted: 1988-08-16
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Expires: 2005-06-11
Abstract
Abstract Microminiature resonant sensor structures are prepared according to micromachining/microfabrication techniques, which structures include thin-film deposits of piezoelectric materials. Such piezoelectric deposits may be excited electrically by including metallized conductive paths during fabrication, or optically. The resonant frequency of the sensor structure is varied by subjecting it to a physical variable, or measurand, such as pressure, temperature, flow rate, etc. Similarly, the resonant frequency of the devices may be detected electrically or optically. The microminiature resonant structures include ribbons and wires, hollow beam and cantilevered hollow beams, and single- and double-ended double beam resonant structures such as tuning forks.
Inventors
- 👤 Gordon W. Chitty
- 👤 Richard H. Morrison, Jr.
- 👤 Everett O. Olsen
- 👤 John G. Panagou
- 👤 Paul M. Zavracky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:27
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/24; H03H9/2405; H03H9/2468; H03H9/2473; H03H3/00; H03H3/007; H03H3/0072; H03H9/02; H03H9/02244; H03H9/02259; H03H2009/02488; H03H2009/02511; H03H2009/02519; Y; Y10; Y10S; Y10S73/00; Y10S73/04; Y10T; Y10T29/00; Y10T29/42; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49103
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
126 words
A method of fabricating a laminar resonant structure, comprising the steps of: (a) preparing a substrate workpiece; (b) securing a laminar material to said substrate; (c) cleaning the exposed laminar material surface; (d) patterning a first resist on the laminar material surface; (e) descumming the resist; (f) etching the workpiece to form a resonant structure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form a piezoelectric slab: (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same; (l) depositing a conductive metallization layer on the workpiece surface and patterning and etching same; (m) removing the resonant structure from the substrate.
Claim 2
Independent Claim
126 words
A method of fabricating a laminar resonant structure, comprising the steps of: (a) preparing a substrate workpiece; (b) securing a laminar material to said substrate; (c) cleaning the exposed laminar material surface; (d) patterning a first resist on the laminar material surface; (e) descumming the resist; (f) etching the workpiece to form a resonant structure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form a piezoelectric slab: (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same; (l) depositing a conductive metallization layer on the workpiece surface and patterning and etching same; (m) removing the resonant structure from the substrate.
Claim 3
Dependent Claim
12 words
The method of claim 1, wherein the laminar material is a metal.
Claim 4
Dependent Claim
11 words
The method of claim 1, wherein the substrate is a glass.
Claim 5
Dependent Claim
13 words
The method of claim 1, wherein the resonant structure formed is a ribbon.
Claim 6
Dependent Claim
14 words
The method of claim 1, wherein the resonant structure formed is a tuning fork.
Claim 7
Dependent Claim
15 words
The method of claim 5, wherein the resonant structure formed is a double tuning fork.
Claim 8
Dependent Claim
14 words
The method of claim 1, wherein the resonant structure formed is a cantilevered beam.
Claim 9
Dependent Claim
12 words
The method of claim 1, wherein the piezoelectric layer is zinc oxide.
Claim 10
Dependent Claim
11 words
The method of claim 1, wherein the piezoelectric layer is cadmium-sulfide.
Claim 11
Dependent Claim
15 words
The method of claim 1, wherein an anisotropic etchant process is used for step f.
Claim 12
Independent Claim
124 words
A method of preparing a laminar resonant structure, comprising the steps of: (a) preparing a substrate workpiece; (b) depositing a metal layer on said substrate; (c) cleaning the exposed metal layer surface; (d) patterning a first resist on the metal surface; (e) descumming the resist; (f) etching the workpiece to form a resonant structure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form a piezoelectric slab; (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same; (l) depositing a conductive metallization layer on the insulation layer and patterning and etching same; (m) removing resonant structure from the substrate.
Claim 13
Independent Claim
124 words
A method of preparing a laminar resonant structure, comprising the steps of: (a) preparing a substrate workpiece; (b) depositing a metal layer on said substrate; (c) cleaning the exposed metal layer surface; (d) patterning a first resist on the metal surface; (e) descumming the resist; (f) etching the workpiece to form a resonant structure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form a piezoelectric slab; (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same; (l) depositing a conductive metallization layer on the insulation layer and patterning and etching same; (m) removing resonant structure from the substrate.
Claim 14
Dependent Claim
12 words
The method of claim 11, wherein the laminar material is a metal.
Claim 15
Dependent Claim
11 words
The method of claim 12, wherein the substrate is a glass.
Claim 16
Dependent Claim
13 words
The method of claim 12, wherein the resonant structure formed is a ribbon.
Claim 17
Dependent Claim
14 words
The method of claim 12, wherein the resonant structure formed is a tuning fork.
Claim 18
Dependent Claim
15 words
The method of claim 15, wherein the resonant structure formed is a double tuning fork.
Claim 19
Dependent Claim
13 words
The method of claim 12, wherein the resonator formed is a cantilevered beam.
Claim 20
Dependent Claim
12 words
The method of claim 12, wherein the piezoelectric layer is zinc oxide.
Claim 21
Dependent Claim
12 words
The method of claim 12, wherein the piezoelectric layer is cadmium sulfide.
Claim 22
Independent Claim
184 words
A method of preparing a hollow beam resonant structure comprising the steps of: (a) etching at least one trough in the front face of a first substrate area, (b) doping a selected trough area of said first substrate area to a predetermined etch-stop depth, (c) depositing a piezoelectric material in a selected one of said at least one trough area, (d) depositing a resistive insulation current blocking layer between said first substrate area and said piezoelectric material, (e) depositing a metallization layer means for communicating drive and sense signals to said piezoelectric material, (f) etching at least one complementary-image trough in the front face surface of a second substrate area, (g) doping a selected trough area of said second substrate area to a predetermined etch-stop depth, (h) aligning the first and second substrate areas in precise registration with their respective front face substrate surfaces joined, (i) bonding said joined front face substrate surfaces together, and (j) etching sufficient undoped substrate away from the doped substrate region to relieve the doped portion from the remaining substrate material, and leave a relieved, hollow microstructural cantilever beam.
Claim 23
Independent Claim
184 words
A method of preparing a hollow beam resonant structure comprising the steps of: (a) etching at least one trough in the front face of a first substrate area, (b) doping a selected trough area of said first substrate area to a predetermined etch-stop depth, (c) depositing a piezoelectric material in a selected one of said at least one trough area, (d) depositing a resistive insulation current blocking layer between said first substrate area and said piezoelectric material, (e) depositing a metallization layer means for communicating drive and sense signals to said piezoelectric material, (f) etching at least one complementary-image trough in the front face surface of a second substrate area, (g) doping a selected trough area of said second substrate area to a predetermined etch-stop depth, (h) aligning the first and second substrate areas in precise registration with their respective front face substrate surfaces joined, (i) bonding said joined front face substrate surfaces together, and (j) etching sufficient undoped substrate away from the doped substrate region to relieve the doped portion from the remaining substrate material, and leave a relieved, hollow microstructural cantilever beam.
Claim 24
Dependent Claim
205 words
A microfabricated laminar resonant microstructure for use in sensing a measurand, fabricated by the steps of: (a) preparing a substrate; (b) releasably securing a laminar material to said substrate; (c) cleaning the exposed laminar material surface; (d) patterning a first resist to outline on the laminar material surface the desired resonant microstructure workpiece; (e) descumming the resist; (f) etching the workpiece to form a resonant microstructure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form at least one piezoelectric slab on the resonant microstructure; (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same to outline areas for apertures through said insulation layer to the surface of the piezoelectric slab; (l) etching through the insulating layer to the surface of the piezoelectric slab to provide apertures through said insulation layer and access to contact areas thereon; (m) depositing a conductive metallization layer on at least a portion of the workpiece surface and patterning and etching same to form desired electrical contact areas through the insulation apertures to the piezoelectric slab underneath; (n) removing the resonant structure from the substrate.
Claim 25
Dependent Claim
205 words
A microfabricated laminar resonant microstructure for use in sensing a measurand, fabricated by the steps of: (a) preparing a substrate; (b) releasably securing a laminar material to said substrate; (c) cleaning the exposed laminar material surface; (d) patterning a first resist to outline on the laminar material surface the desired resonant microstructure workpiece; (e) descumming the resist; (f) etching the workpiece to form a resonant microstructure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form at least one piezoelectric slab on the resonant microstructure; (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same to outline areas for apertures through said insulation layer to the surface of the piezoelectric slab; (l) etching through the insulating layer to the surface of the piezoelectric slab to provide apertures through said insulation layer and access to contact areas thereon; (m) depositing a conductive metallization layer on at least a portion of the workpiece surface and patterning and etching same to form desired electrical contact areas through the insulation apertures to the piezoelectric slab underneath; (n) removing the resonant structure from the substrate.
Claim 26
Dependent Claim
205 words
A microfabricated resonant microstructure for use in sensing a measurand, fabricated by the steps of: (a) preparing a substrate; (b) releasably depositing a metallization layer on said substrate; (c) cleaning the exposed metallization layer surface; (d) patterning a first resist to outline on the metallization surface the desired resonant microstructure; (e) descumming the resist; (f) etching the workpiece to form a resonant microstructure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form at least one piezoelectric slab on the resonant microstructure (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same to outline areas for apertures through said insulation layer to contact areas on the surface of the piezoelectric slab; (l) etching through the insulating layer to the surface of the piezoelectric slab to provide apertures through said insulation layer and access to contact areas thereon; (m) depositing a conductive metallization layer on at least a portion of the workpiece surface and patterning and etching means to form desired electrical contact areas through the insulation aperture to the piezoelectric slab underneath; (n) removing the resonant structure from the substrate.
Claim 27
Dependent Claim
205 words
A microfabricated resonant microstructure for use in sensing a measurand, fabricated by the steps of: (a) preparing a substrate; (b) releasably depositing a metallization layer on said substrate; (c) cleaning the exposed metallization layer surface; (d) patterning a first resist to outline on the metallization surface the desired resonant microstructure; (e) descumming the resist; (f) etching the workpiece to form a resonant microstructure on the substrate; (g) cleaning and baking the workpiece; (h) depositing a piezoelectric layer on the workpiece surface; (i) patterning and etching the piezoelectric layer to form at least one piezoelectric slab on the resonant microstructure (j) cleaning and rinsing the workpiece; (k) applying an insulation layer on the workpiece surface and patterning same to outline areas for apertures through said insulation layer to contact areas on the surface of the piezoelectric slab; (l) etching through the insulating layer to the surface of the piezoelectric slab to provide apertures through said insulation layer and access to contact areas thereon; (m) depositing a conductive metallization layer on at least a portion of the workpiece surface and patterning and etching means to form desired electrical contact areas through the insulation aperture to the piezoelectric slab underneath; (n) removing the resonant structure from the substrate.
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) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |