Patent US4960069A successfully refreshed from Google Patents.
US3674580A
Expired / Lapsed
US
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Zirconium mask for semiconductor fabricated using alkaline etchants
Assignee: AT&T Inc
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Filing: 1970-05-08
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Granted: 1972-07-04
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Expires: 1990-05-08
Abstract
Abstract A MASK COMPRISING A THIN FILM OF ZIRCONIUM METAL IS APPLIED DIRECTLY TO A SEMICONDUCTOR SURFACE FOR USE WITH STRONG ALKALINE ETCHANTS, SUCH AS POTASSIUM HYDROXIDE, OF THE TYPE USED FOR ANTISOTROPIC ETCHING. TYPICALLY, A ZIRCONIUM FILM OF SEVERAL HUNDRED ANGSTRONS THICKNESS IS APPLIED USING HIGH ENERGY MEANS INCLUDING SPUTTERING AND AN ELECTRON GUN.
Inventors
- 👤 William Charles Erdman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:26
CPC Classifications
H; H10; H10P; H10P95/00; H10P50/00; H10P50/69; H10P50/691; H10P50/692; H10W; H10W74/00; H10W74/40; H10W74/43; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/945
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |