US6004832A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating an electrostatic ultrasonic transducer
Assignee: Leland Stanford Junior University
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Filing: 1997-01-31
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Granted: 1999-12-21
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Expires: 2017-01-31
Abstract
Abstract A method of fabrication wherein a nitride layer is spaced from a conductive substrate by an insulating layer and etching removes at least portions of an insulating layer to leave a nitride membrane spaced from the substrate. The surface of the conductive layer where the insulating layer is removed is chemically roughened and the etchant is removed by freeze-drying and sublimation to eliminate sticking of the nitride layer to the substrate surface during fabrication.
Inventors
- 👤 Matthew Isaac Haller
- 👤 Butrus Thomas Khuri-Yakub
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:22
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/0292; B06B1/06; B06B1/0688; B06B1/0696; H; H02; H02N; H02N1/00; H02N1/002; H02N1/006
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
160 words
The method of fabricating an electrostatic ultrasonic transducer array including a plurality of ultrasonic transducers each having spaced electrodes comprising the steps of: providing a substrate of conductive silicon material; forming a layer of silicon nitride on said substrate; selectively etching the silicon nitride layer to form a support structure which exposes therebetween a shaped area of the surface of the substrate; growing a silicon oxide layer on the exposed surface of the substrate between said support structure; growing a membrane layer of low stress silicon nitride directly over such silicon oxide layer and silicon nitride support structure; forming a metal layer on the surface of said silicon nitride layer; forming openings in said metal layer and said silicon nitride membrane layer to expose the silicon oxide between the silicon nitride support structure; and etching away all of the silicon oxide to leave a silicon nitride membrane at shaped area supported above the substrate by the silicon nitride support structure.
Claim 2
Independent Claim
160 words
The method of fabricating an electrostatic ultrasonic transducer array including a plurality of ultrasonic transducers each having spaced electrodes comprising the steps of: providing a substrate of conductive silicon material; forming a layer of silicon nitride on said substrate; selectively etching the silicon nitride layer to form a support structure which exposes therebetween a shaped area of the surface of the substrate; growing a silicon oxide layer on the exposed surface of the substrate between said support structure; growing a membrane layer of low stress silicon nitride directly over such silicon oxide layer and silicon nitride support structure; forming a metal layer on the surface of said silicon nitride layer; forming openings in said metal layer and said silicon nitride membrane layer to expose the silicon oxide between the silicon nitride support structure; and etching away all of the silicon oxide to leave a silicon nitride membrane at shaped area supported above the substrate by the silicon nitride support structure.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-20 | 2003-06-21 | 2003-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-20 | 2007-06-21 | 2007-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-20 | 2011-06-21 | 2011-12-21 | $7700.00 | Window Closed / Lapsed |