US3933544A
Expired / Lapsed
US
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Method of etching copper and copper alloys
Assignee: Hollmuller Hans Maschinenbau GmbH and Co
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Filing: 1973-08-06
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Granted: 1976-01-20
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Expires: 1993-08-06
Abstract
Abstract A method of etching copper and copper alloys by means of an ammoniacal etching solution containing chloride ions and for regenerating this etching solution during this etching process by adding an ammoniacal compound, for example, in the form of ammonium hydroxide or ammonia gas, as well as hydrochloric acid and water to the etching solution in accordance with continuous measurements of the pH-value and the specific gravity of the etching solution.
Inventors
- 👤 Rainer Haas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:04
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
182 words
A method of etching copper and copper alloys, comprising: forming an etching medium consisting of an ammoniacal etching solution containing chloride ions, thereby producing a copper-I compound; regenerating the copper-I compound formed during the etching process by reacting therewith a chloro compound selected from the group which consists of HCl, ammonium chloride and NaCl only during the etching process by the addition of the chloro compound to said solution at a rate corresponding to the rate of formation of said copper-I compound; and supplying to said solution an amount of an ammoniacal compound selected from the group which consists of ammonium hydroxide and ammonia gas such that the pH-value of the latter is maintained at about 8.5 to 10.0, the copper content per liter of etching medium being maintained at a substantially constant value by the addition of water, the addition of the chloro compound to the etching medium to be regenerated being controlled in dependence upon the redox potential of the etching medium, while the molar ratio of the chloro compound to the ammoniacal compound amounts substantially to 1 to 2.
Claim 2
Independent Claim
182 words
A method of etching copper and copper alloys, comprising: forming an etching medium consisting of an ammoniacal etching solution containing chloride ions, thereby producing a copper-I compound; regenerating the copper-I compound formed during the etching process by reacting therewith a chloro compound selected from the group which consists of HCl, ammonium chloride and NaCl only during the etching process by the addition of the chloro compound to said solution at a rate corresponding to the rate of formation of said copper-I compound; and supplying to said solution an amount of an ammoniacal compound selected from the group which consists of ammonium hydroxide and ammonia gas such that the pH-value of the latter is maintained at about 8.5 to 10.0, the copper content per liter of etching medium being maintained at a substantially constant value by the addition of water, the addition of the chloro compound to the etching medium to be regenerated being controlled in dependence upon the redox potential of the etching medium, while the molar ratio of the chloro compound to the ammoniacal compound amounts substantially to 1 to 2.
Claim 3
Dependent Claim
16 words
A method as defined in claim 1, in which the ammoniacal compound consists of ammonia gas.
Claim 4
Dependent Claim
26 words
A method as defined in claim 1, in which the addition of the ammoniacal compound is controlled in dependence upon the pH-value of the etching medium.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-19 | 1979-07-21 | 1980-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-19 | 1983-07-21 | 1984-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-19 | 1987-07-21 | 1988-01-20 | $7700.00 | Window Closed / Lapsed |