US4690693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High purity silicon nitride polishing compound
Assignee: Osram Sylvania Inc
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Filing: 1985-12-05
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Granted: 1987-09-01
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Expires: 2005-12-05
Abstract
Abstract A polishing compound is disclosed which is relatively high purity silicon nitride, the silicon nitride comprising particles having equiaxial crystals, the particle size being from about 0.03 to about 5 microns.
Inventors
- 👤 Robert J. Dobbs
- 👤 Shuford M. Alexander, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:06
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P90/129; C; C09; C09K; C09K3/00; C09K3/14; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/259
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
30 words
A polishing compound of relatively high purity silicon nitride, said silicon nitride comprising particles having essentially equiaxial crystals, the particle size being from about 0.03 microns to about 5 microns.
Claim 2
Dependent Claim
30 words
A polishing compound of relatively high purity silicon nitride, said silicon nitride comprising particles having essentially equiaxial crystals, the particle size being from about 0.03 microns to about 5 microns.
Claim 3
Dependent Claim
18 words
A polishing compound of claim 1 wherein said silicon nitride has a purity of at least about 94%.
Claim 4
Dependent Claim
17 words
A polishing compound of claim 1 wherein a portion of said silicon nitride is alpha silicon nitride.
Claim 5
Dependent Claim
17 words
A polishing compound of claim 3 wherein essentially all of said silicon nitride is alpha silicon nitride.
References Cited (Backward Citations)
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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) | 1990-08-31 | 1991-03-02 | 1991-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-31 | 1995-03-02 | 1995-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-31 | 1999-03-02 | 1999-09-01 | $7700.00 | Window Closed / Lapsed |