US3887405A
Expired / Lapsed
US
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Method and composition for cleaning copper surfaces
Assignee: 3M Co
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Filing: 1974-05-10
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Granted: 1975-06-03
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Expires: 1994-05-10
Abstract
Abstract The surfaces of copper workpieces are mildly etched by an aqueous composition containing potassium monopersulfate, a watersoluble chloride and sulfuric acid sufficient to provide a pH of 0.2-1.8. An alkali metal sulfate is an optional additive, and the bath is operated at a temperature of 10*-70* Centigrade and preferably about 20*-35* Centigrade.
Inventors
- 👤 Jaan-Jiue Fong
- 👤 Merton M Beckwith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:33
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/10; C23F1/14; C23F1/16; C23F1/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
56 words
A MILD ETCHANT FOR COPPER WORKPIECES CONSISTING ESSENTIALLY OF AN AQUEOUS SLUTION OF 60-240 GRAMS PER LITER OF AN ALKALI METAL OONOPERSULFATE, 15-500 PARTS PER MILLION OF A WATER-SOLUBLE INORGANIC CHLORIDE COMPOUND, SULFURIC ACID IN AN AMOUNT SUFFICIENT TO PROVIDE A PH TO 0.2-1.8, AND UP TO 10 GRAMS PER LITER OF AN ALKALI METAL SULFATE.
Claim 2
Dependent Claim
56 words
A MILD ETCHANT FOR COPPER WORKPIECES CONSISTING ESSENTIALLY OF AN AQUEOUS SLUTION OF 60-240 GRAMS PER LITER OF AN ALKALI METAL OONOPERSULFATE, 15-500 PARTS PER MILLION OF A WATER-SOLUBLE INORGANIC CHLORIDE COMPOUND, SULFURIC ACID IN AN AMOUNT SUFFICIENT TO PROVIDE A PH TO 0.2-1.8, AND UP TO 10 GRAMS PER LITER OF AN ALKALI METAL SULFATE.
Claim 3
Dependent Claim
56 words
A mild etchant for copper workpieces consisting essentially of an aqueous solution of 60-240 grams per liter of an alkali metal monopersulfate, 15-500 parts per million of a water-soluble inorganic chloride compound, sulfuric acid in an amount sufficient to provide a pH of 0.2-1.8, and up to 10 grams per liter of an alkali metal sulfate.
Claim 4
Dependent Claim
56 words
A mild etchant for copper workpieces consisting essentially of an aqueous solution of 60-240 grams per liter of an alkali metal monopersulfate, 15-500 parts per million of a water-soluble inorganic chloride compound, sulfuric acid in an amount sufficient to provide a pH of 0.2-1.8, and up to 10 grams per liter of an alkali metal sulfate.
Claim 5
Dependent Claim
15 words
The etchant in accordance with claim 1 wherein said alkali metal monopersulfate is potassium monopersulfate.
Claim 6
Dependent Claim
22 words
The etchant in accordance with claim 1 wherein said alkali metal sulfate is present in an amount of 0.5-4 grams per liter.
Claim 7
Dependent Claim
31 words
The etchant in accordance with claim 1 wherein said water-soluble inorganic chloride compound is an alkali metal chloride and is present in an amount of less than 300 parts per million.
Claim 8
Dependent Claim
63 words
The etchant in accordance with claim 1 wherein the said alkali metal monopersulfate is potassium monopersulfate in an amount of 90-200 grams per liter, wherein said water soluble chloride compound is an alkali metal chloride and is present in an amount of 30-60 parts per million, and wherein said sulfuric acid is present in an amount sufficient to provide a pH of 0.8-1.5.
Claim 9
Dependent Claim
22 words
The etchant in accordance with claim 5 wherein said alkali metal sulfate is present in an amount of 0.5-4 grams per liter.
Claim 10
Independent Claim
101 words
A method for mildly etching the surfaces of copper workpieces comprising preparing an aqueous solution consisting essentially of 60-240 grams per liter of an alkali metal monopersulfate, 15-500 parts per million of a water-soluble inorganic chloride compound, sulfuric acid in an amount sufficient to provide a pH of 0.2-1.8 and up to 10 grams per liter of an alkali metal sulfate; maintaining said aqueous solution at a temperature of 10*-70* Centigrade; and Immersing a workpiece having a copper surface in said solution for a period of time sufficient to produce the desired uniform etching action upon the surface of the workpiece.
Claim 11
Independent Claim
101 words
A method for mildly etching the surfaces of copper workpieces comprising preparing an aqueous solution consisting essentially of 60-240 grams per liter of an alkali metal monopersulfate, 15-500 parts per million of a water-soluble inorganic chloride compound, sulfuric acid in an amount sufficient to provide a pH of 0.2-1.8 and up to 10 grams per liter of an alkali metal sulfate; maintaining said aqueous solution at a temperature of 10*-70* Centigrade; and Immersing a workpiece having a copper surface in said solution for a period of time sufficient to produce the desired uniform etching action upon the surface of the workpiece.
Claim 12
Dependent Claim
28 words
The method in accordance with claim 7 wherein said solution is maintained at a termperature of 20*-35* Centigrade and wherein the sulfuric acid provides a pH of 0.8-1.5.
Claim 13
Dependent Claim
15 words
The method in accordance with claim 7 wherein said alkali metal monopersulfate is potassium monopersulfate.
Claim 14
Dependent Claim
22 words
The method in accordance with claim 7 wherein said alkali metal sulfate is present in an amount of 0.5-4 grams per liter.
Claim 15
Dependent Claim
31 words
The method in accordance with claim 7 wherein said water-soluble inorganic chloride compound is an alkali metal chloride and is present in an amount of less than 300 parts per million.
References Cited (Backward Citations)
US2291202A
Cited
US3216873A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |