Patent US3716428A successfully refreshed from Google Patents.
US3716428A
Expired / Lapsed
US
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Method of etching a metal which can be passivated
Assignee: Alcatel Lucent SAS
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Filing: 1971-02-09
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Granted: 1973-02-13
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Expires: 1991-02-09
Abstract
Abstract A process for etching a first metal which can be passivated, wherein a layer of a second metal which is more oxidizable than the first metal is deposited on the first metal, and the first metal and second metal layer are thereafter immersed in an acid solution.
Inventors
- 👤 C Amouroux
- 👤 G Peres
- 👤 P Valette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:56
CPC Classifications
H; H10; H10P; H10P95/00; C; C23; C23F; C23F1/00; C23F1/02; H10W; H10W20/00; H10W20/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
In a method for lithographing a metal which can be passivated, wherein a protective layer is deposited on a first metal, and the first metal is etched by an acid solution which the protective layer resists, the improvement comprising: depositing over the protective layer and the unprotected area of the first metal a layer of an auxiliary metal which is more oxidizable than the first so as to depassivate said first metal, and etching said auxiliary metal with an acid, which the protective layer resists, immediately prior to the acid etching of the first metal so as to completely remove said auxiliary metal.
Claim 2
Dependent Claim
103 words
In a method for lithographing a metal which can be passivated, wherein a protective layer is deposited on a first metal, and the first metal is etched by an acid solution which the protective layer resists, the improvement comprising: depositing over the protective layer and the unprotected area of the first metal a layer of an auxiliary metal which is more oxidizable than the first so as to depassivate said first metal, and etching said auxiliary metal with an acid, which the protective layer resists, immediately prior to the acid etching of the first metal so as to completely remove said auxiliary metal.
Claim 3
Dependent Claim
18 words
The method according to claim 1, wherein the first metal is platinum and the auxiliary metal is silver.
Claim 4
Dependent Claim
140 words
In a method for the selective metallizing of an electronic semiconductor device by a first metal which can be passivated, wherein the first metal is deposited non-selectively on the device, a protective layer is deposited selectively on the first metal, and the first metal is etched by an acid solution which the protective layer resists, the improvement comprising the steps of depositing on the protective layer and the unprotected areas of the first metal, an auxiliary metal that is more oxidizable than the first metal after the selective depositing of the protective layer and before the etching of said first metal so as to depassivate said first metal, and acid etching said auxiliary metal with an acid which the protective layer resists immediately prior to the acid etching of the first metal so as to completely remove said auxiliary metal.
Claim 5
Dependent Claim
140 words
In a method for the selective metallizing of an electronic semiconductor device by a first metal which can be passivated, wherein the first metal is deposited non-selectively on the device, a protective layer is deposited selectively on the first metal, and the first metal is etched by an acid solution which the protective layer resists, the improvement comprising the steps of depositing on the protective layer and the unprotected areas of the first metal, an auxiliary metal that is more oxidizable than the first metal after the selective depositing of the protective layer and before the etching of said first metal so as to depassivate said first metal, and acid etching said auxiliary metal with an acid which the protective layer resists immediately prior to the acid etching of the first metal so as to completely remove said auxiliary metal.
Claim 6
Dependent Claim
12 words
The method according to claim 3, wherein the auxiliary metal is silver.
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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) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |