US3785945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for electrolytically etching tungsten
Assignee: AT&T Inc
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Filing: 1972-05-04
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Granted: 1974-01-15
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Expires: 1992-05-04
Abstract
Abstract A TECHNIQUE FOR ELECTROLYTICALLY ETCHING TUNGSTEN FILMS INVOLVES THE USE OF BORATE PHOSPHATE AND CARBONATE BUFFERED ELECTROLYTES HAVING A PH WITHIN THE RANGE OF 7.0 TO 10.5. THE DESCRIBED PROCESS PERMITS AUTOMATION OF THE ETCHING PROCESS AND ELIMINATES THE FORMATION OF ISOLATED ISLANDS OF UNETCHED MATERIALS.
Inventors
- 👤 D Macarthur
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:42
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; C; C25; C25F; C25F3/00; C25F3/02; C25F3/08; C25F7/00
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) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |