US3773670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel etchant for etching thin metal films
Assignee: International Business Machines Corp
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Filing: 1971-09-14
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Granted: 1973-11-20
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Expires: 1991-09-14
Abstract
Abstract A composition for etching thin films of metal, such as chromium or molybdenum, comprising alkaline metal salts of weak organic acids which yield solutions having a pH in the range of 12 to 13.5 e.g. sodium or potassium-meta or orthosilicates or sodium orthophosphate, and oxidizing agents active in alkaline solutions, such as potassium permanganate or sodium ferricyanide.
Inventors
- 👤 L Colom
- 👤 H Levine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:03
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/32; C23F1/38
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
12 words
The composition of claim 1 wherein said salt comprises a sodium silicate.
Claim 2
Dependent Claim
12 words
The composition of claim 1 wherein said salt comprises a sodium phosphate.
Claim 3
Dependent Claim
24 words
The composition of claim 1 wherein said salt comprises a mixture of sodium meta-silicate and sodium ortho-phosphate and said oxidizing agent is potassium permanganate.
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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |