US5264387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming uniformly thin, isolated silicon mesas on an insulating substrate
Assignee: International Business Machines Corp
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Filing: 1992-10-27
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Granted: 1993-11-23
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Expires: 2012-10-27
Abstract
Abstract A method comprising the steps of: providing a substrate including an insulator material having a generally planar surface; forming a plurality of mesas of a semiconductor material on the substrate surface, the plurality of mesas spaced by channels extending to the substrate surface, the plurality of mesas including device mesas and dummy mesas; forming a polish-stop structure of at least one selected material over the substrate surface in the channels; polishing the plurality of mesas and stopping on the polish-stop structure whereby the plurality of mesas have the same thickness as the polish-stop structure; and replacing the dummy mesas with an insulator material whereby to electrically isolate the device mesas.
Inventors
- 👤 Klaus D. Beyer
- 👤 Mark A. Jaso
- 👤 Subramanian S. Iyer
- 👤 Scott R. Stiffler
- 👤 James D. Warnock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:11
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/403; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10W; H10W10/00; H10W10/01; H10W10/061; H10W10/10; H10W10/181; H10W10/011; H10W10/014; H10W10/17; Y; Y10; Y10S; Y10S438/00; Y10S438/977
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
A method comprising the steps of: providing a substrate including an insulator material having a generally planar surface; forming a plurality of mesas of a semiconductor material on said substrate surface, said plurality of mesas spaced by channels extending to said substrate surface, said plurality of mesas including device mesas and dummy mesas; forming a polish-stop structure of at least one selected material over said substrate surface in said channels; polishing said plurality of mesas and stopping on said polish-stop structure whereby said plurality of mesas have the same thickness as said polish-stop structure; and replacing said dummy mesas with an insulator material whereby to electrically isolate said device mesas.
Claim 2
Independent Claim
110 words
A method comprising the steps of: providing a substrate including an insulator material having a generally planar surface; forming a plurality of mesas of a semiconductor material on said substrate surface, said plurality of mesas spaced by channels extending to said substrate surface, said plurality of mesas including device mesas and dummy mesas; forming a polish-stop structure of at least one selected material over said substrate surface in said channels; polishing said plurality of mesas and stopping on said polish-stop structure whereby said plurality of mesas have the same thickness as said polish-stop structure; and replacing said dummy mesas with an insulator material whereby to electrically isolate said device mesas.
Claim 3
Dependent Claim
28 words
A method in accordance with claim 1 wherein said step of replacing said dummy mesas with an insulator material comprises converting said dummy mesas to said insulator material.
Claim 4
Dependent Claim
58 words
A method in accordance with claim 2 wherein said step of converting said dummy mesas to said insulator material further includes the step of simultaneously converting at least a portion of said polish-stop structure to said insulator material, whereby the converted dummy mesas and converted portion of said polish-stop structure form an integral layer of said insulator material.
Claim 5
Dependent Claim
43 words
A method in accordance with claim 3 wherein said converting step comprises exposing said dummy mesas and said portion of said polish-stop layer to an oxidizing environment to convert said dummy mesas and said portion of said polish-stop structure to an oxide insulator.
Claim 6
Dependent Claim
102 words
A method in accordance with claim 1 wherein said step of forming a polish-stop structure comprises the steps of: forming a conformal layer of said at least one selected material over said substrate and said plurality of mesas; said conformal layer of said at least one selected material having a thickness less than the thickness of said plurality of mesas; and removing said conformal layer of said at least one selected material from the top and side surfaces of said plurality of mesas, leaving said conformal layer of at least one selected material on the surface of said substrate within said channels.
Claim 7
Dependent Claim
53 words
A method in accordance with claim 4 wherein said step of converting said dummy mesas and said portion of said polish-stop structure to an insulator material includes the step of forming a protective layer of an oxidation-resistant material over said device mesas, thereby inhibiting said device mesas from being converted to an oxide.
Claim 8
Dependent Claim
38 words
A method in accordance with claim 6 wherein said protective layer is contained within and slightly smaller than the upper surface of said device mesas, whereby the edges of said device mesas are oxidized during said converting step.
Claim 9
Dependent Claim
36 words
A method in accordance with claim 1 wherein said step of polishing said plurality of mesas comprises chemically-mechanically polishing said plurality of mesas using polishing materials selective to said plurality of mesas over said polish-stop structure.
Claim 10
Dependent Claim
36 words
A method in accordance with claim 4 wherein said step of polishing said plurality of mesas comprises chemically-mechanically polishing said plurality of mesas using polishing materials selective to said plurality of mesas over said polish-stop structure.
Claim 11
Dependent Claim
46 words
A method in accordance with claim 2 wherein said step of converting said dummy mesas and said portion of said polish-stop structure to an insulator material further comprises the steps of forming a layer of protective material over said device mesas before performing said converting step.
Claim 12
Dependent Claim
40 words
A method in accordance with claim 10 wherein said layer of protective material is contained within and slightly smaller than the upper surface of said device mesas, whereby the edges of said device mesas are oxidized during said converting step.
Claim 13
Dependent Claim
20 words
A method in accordance with claim 4 wherein: said semiconductor material includes silicon; and said polish-stop structure comprises silicon dioxide.
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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) | 1996-11-22 | 1997-05-24 | 1997-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-22 | 2001-05-24 | 2001-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-22 | 2005-05-24 | 2005-11-23 | $7700.00 | Window Closed / Lapsed |