US3718514A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of projections on epitaxial layers
Assignee: AT&T Inc
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Filing: 1971-05-28
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Granted: 1973-02-27
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Expires: 1991-05-28
Abstract
Abstract A METHOD FOR REMOVING PROJECTIONS FROM THE SURFACE OF EPITAXIALLY-DEPOSITED SEMICONDUCTOR LAYERS IS DESCRIBED. THESE PROJECTIONS CAN ADVERSELY AFFECT THE RESULTS OF PHOTOLITHOGRAPHIC PROCESSING. THE METHOD INVOLVES PRODUCING AN OXIDE LAYER ON THE SURFACE AND APPLYING A DISCONTINIOUS FILM TO THE OXIDE IN SUCH A MANNER THA THE DISCONTINUITIES PREFERENTIALLY ALIGN WITH THE PROJECTIONS. BY MEANS OF A SERIES OF ETCHING STEPS, THE PROJECTIONS ARE SELECTIVELY REMOVE WITHOUT AFFECTING THE INTEGRITY OF THE EPITAXIAL LAYER.
Inventors
- 👤 W Erdman
- 👤 P Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:50
CPC Classifications
H; H10; H10P; H10P95/00; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/644; H10W; H10W74/00; H10W74/40; H10W74/47; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/106
Claims Analysis
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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) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |