US5683546A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of etching silicon substrate at different etching rates for different planes of the silicon to form an air bridge
Assignee: Ricoh Seiki Co Ltd
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Filing: 1993-10-22
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Granted: 1997-11-04
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Expires: 2013-10-22
Abstract
Abstract The present invention is for enlarging a freedom of layout including an air bridge pattern and enhancing the availability for various purposes. A mask layer including an air bridge pattern is formed on a (100) plane of a silicon substrate, isotropic etching is carried out until a point of intersection between tangents of a peripheral curved plane comes to under the air bridge pattern plane, and then an air bridge is formed by means of anisotropic etching.
Inventors
- 👤 Junji Manaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 00:44
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644; B; B81; B81C; B81C1/00; B81C1/00015; B81C1/00134; B81C1/00142; B81C1/00436; B81C1/00555; B81C1/00626; G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0042; B81B; B81B2203/00; B81B2203/03; B81B2203/0315; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/924
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
86 words
A method of etching a silicon substrate, for forming an air bridge by making use of differences in etching rates for respective crystal planes of a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100) plane of the silicon substrate; generating isotropic defects in said silicon substrate by electrically irradiating the silicon substrate with ions of an inactive element which is heavier than Si; and forming an air bridge by anisotropic etching of the irradiated silicon substrate.
Claim 2
Independent Claim
86 words
A method of etching a silicon substrate, for forming an air bridge by making use of differences in etching rates for respective crystal planes of a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100) plane of the silicon substrate; generating isotropic defects in said silicon substrate by electrically irradiating the silicon substrate with ions of an inactive element which is heavier than Si; and forming an air bridge by anisotropic etching of the irradiated silicon substrate.
Claim 3
Independent Claim
90 words
A method of etching a silicon substrate, for forming an air bridge by making use of differences in etching rates for respective crystal planes of a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100 plane of a silicon substrate; generating isotropic defects in said silicon substrate by irradiating the silicon substrate with ions of an inactive element which is heavier than Si using a sputter etching process; and forming an air bridge by anisotropic etching of the irradiated silicon substrate.
Claim 4
Independent Claim
90 words
A method of etching a silicon substrate, for forming an air bridge by making use of differences in etching rates for respective crystal planes of a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100 plane of a silicon substrate; generating isotropic defects in said silicon substrate by irradiating the silicon substrate with ions of an inactive element which is heavier than Si using a sputter etching process; and forming an air bridge by anisotropic etching of the irradiated silicon substrate.
Claim 5
Independent Claim
128 words
A method of etching a silicon substrate, for forming an air bridge by making use of a difference in etching rate for each crystal plane of silicon in a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100) plane of the silicon substrate; plasma etching isotropically to undercut the masked silicon substrate on opposite sides of the air bridge pattern, until a point of intersection between tangents of a peripheral plane surrounding a cavity undercut under the air bridge pattern, wherein each tangent is inclined at 54.74° to the silicon substrate, is located just underneath a plane of the air bridge pattern; and forming an air bridge by anisotropic etching of the silicon substrate beneath the air bridge pattern.
Claim 6
Independent Claim
128 words
A method of etching a silicon substrate, for forming an air bridge by making use of a difference in etching rate for each crystal plane of silicon in a silicon substrate, comprising the steps of: forming a mask layer including an air bridge pattern on a (100) plane of the silicon substrate; plasma etching isotropically to undercut the masked silicon substrate on opposite sides of the air bridge pattern, until a point of intersection between tangents of a peripheral plane surrounding a cavity undercut under the air bridge pattern, wherein each tangent is inclined at 54.74° to the silicon substrate, is located just underneath a plane of the air bridge pattern; and forming an air bridge by anisotropic etching of the silicon substrate beneath the air bridge pattern.
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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) | 2000-11-03 | 2001-05-05 | 2001-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-03 | 2005-05-05 | 2005-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-03 | 2009-05-05 | 2009-11-04 | $7700.00 | Window Closed / Lapsed |