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US4424097A
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Metal stripping process and composition
Assignee: ELGET ING BURO fur GRAFISCHE und ELEKTRONISCHE TECHNIK GOETHESTRASSE
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Filing: 1982-08-09
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Granted: 1984-01-03
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Expires: 2002-08-09
Abstract
Abstract A stripper, for the removal of tin and tin compounds, in particular copper metal-resists in contact switches, comprises an aqueous solution of 5 to 20% v/v hydrochloric acid, 2.5 to 6.0 g/l copper and 9 to 40 g/l tin, as well as, at the beginning of the stripping process, up to 0.5 ml/l hydrogen peroxide or up to 0.015 ml/l of a surfactant.
Inventors
- 👤 Erich Lipka
- 👤 Eberhard Lendle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:53
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/44; H; H05; H05K; H05K3/00; H05K3/02; H05K3/06; H05K3/067
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
29 words
A process for the removal of tin and tin alloys, which comprises applying an aqueous solution containing 5 to 20% v/v hydrochloric acid and 2.5 to 6.0 g/l copper.
Claim 2
Dependent Claim
29 words
A process for the removal of tin and tin alloys, which comprises applying an aqueous solution containing 5 to 20% v/v hydrochloric acid and 2.5 to 6.0 g/l copper.
Claim 3
Dependent Claim
11 words
The process of claim 1, for the removal of copper metal-resists.
Claim 4
Dependent Claim
19 words
The process of claim 1, in which up to 0.5 ml/l hydrogen peroxide is initially added to the solution.
Claim 5
Dependent Claim
20 words
The process of claim 1, in which up to 0.015 ml/l of a surfactant is added initially to the solution.
Claim 6
Dependent Claim
21 words
The process of claim 1, in which the tin content of the solution is maintained constant at 9 to 40 g/l.
Claim 7
Dependent Claim
26 words
The process of claim 1, in which the tin and copper contents of the solution are controlled to a constant level, colorimetrically or using redox potentials.
Claim 8
Dependent Claim
18 words
The process of claim 1, in which metals are removed from the solution using a metal recovery cell.
Claim 9
Dependent Claim
15 words
The process of claim 1, in which hydrochloric acid is added continuously to the solution.
References Cited (Backward Citations)
US4260451A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |