US3775265A
Expired / Lapsed
US
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Method of plating copper on aluminum
Assignee: Canada Wire and Cable Co Ltd
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Filing: 1970-09-25
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Granted: 1973-11-27
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Expires: 1990-09-25
Abstract
Abstract Copper is electroplated directly onto aluminum by immersing an aluminum workpiece in an aqueous alkaline plating bath containing a divalent copper salt and an amine capable of complexing the copper, and passing an electric current through the plating bath using the workpiece as the cathode. The deposits which are obtained are strongly adherent and the method avoids the need for complicated mechanical or chemical pretreatment of the workpiece.
Inventors
- 👤 N Bharucha
- 👤 M Janjua
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:07
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/34; C25D5/42; C25D5/44; C25D3/00; C25D3/02; C25D3/38
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
144 words
A method of electroplating copper directly onto aluminum without the necessity of providing a pretreatment zinc coating which comprises the steps of a. immersing an aluminum workpiece in an aqueous plating bath having a pH of 8.5 to 13 consisting essentially of from 5 to 450 grams per liter of ammonium hydroxide from 5 to 450 grams per liter of the nitrate, sulfate, acetate or chloride salt of divalent copper and from 5 to 450 grams per liter of a complexing agent selected from the group consisting of primary, secondary and tertiary amines, whereby said complexing agent is capable of forming a complex ion with divalent copper; and b. passing an electric current through said bath between said workpiece as the cathode and an anode, said electric current being of sufficient density to achieve the desired plating of a layer of copper on aluminum.
Claim 2
Dependent Claim
36 words
Method as claimed in claim 1, wherein the plating bath comprises from 50 to 200 grams per litre of the salt of divalent copper and from 50 to 200 grams per litre of the complexing agent.
Claim 3
Dependent Claim
36 words
Method as claimed in claim 1, wherein the plating bath comprises from 100 to 200 grams per litre of the salt of divalent copper and from 100 to 200 grams per litre of the complexing agent.
Claim 4
Dependent Claim
22 words
Method as claimed in claim 1, wherein the copper salt is selected from copper nitrate, copper sulfate, copper acetate and copper chloride.
Claim 5
Dependent Claim
40 words
Method as claimed in claim 1, wherein the amine contains at least two nitrogen atoms and is capable of forming a chelate with divalent copper, said amine being admixed with ammonium hydroxide of predetermined concentration to form the complexing agent.
Claim 6
Dependent Claim
30 words
Method as claimed in claim 16, wherein the amine is selected from ethylenediamine, diethylenetriamine and tetraethylenepentamine and is admixed with ammonium hydroxide of predetermined concentration to form the complexing agent.
Claim 7
Dependent Claim
41 words
Method as claimed in claim 1, wherein the copper salt is selected from copper nitrate, copper sulfate, copper acetate and copper chloride and the complexing agent is an admixturE of ammonium hydroxide with an amine selected from ethylenediamine, diethylenetriamine and tetraethylenepentamine.
Claim 8
Dependent Claim
16 words
Method as claimed in claim 1, wherein the plating bath temperature is from 25* to 90*C.
Claim 9
Dependent Claim
16 words
Method as claimed in claim 19, wherein the plating bath temperature is from 25* to 30*C.
Claim 10
Dependent Claim
20 words
Method as claimed in claim 1, wherein the operating current density is from 10 to 300 amperes per square foot.
Claim 11
Dependent Claim
20 words
Method as claimed in claim 1, wherein the operating voltage of the plating bath is from 5 to 25 volts.
Claim 12
Dependent Claim
20 words
Method as claimed in claim 1, wherein the aluminum workpiece is degreased before it is immersed into the plating bath.
Claim 13
Dependent Claim
46 words
Method as claimed in claim 13, wherein the aluminum workpiece is degreased before it is immersed into the plating bath by treating with an aqueous solution of sodium bicarbonate, sodium hydroxide and trisodium phosphate, rinsing with water, etching with nitric acid and again rinsing with water.
Claim 14
Dependent Claim
17 words
Method as claimed in claim 1, wherein the plating bath also contains a source of fluoride ions.
Claim 15
Dependent Claim
127 words
Method as claimed in claim 1, wherein the copper salt is selected from copper nitrate, copper sulfate, copper acetate and copper chloride and the complexing agent is an admixture of ammonium hydroxide with an amine selected from ethylenediamine, diethylenetriamine and tetraethylenepentamine, the electroplating being carried out at current densities between 10 and 300 amperes per square foot and at voltages between 5 to 25 volts to achieve desired plating of copper on aluminum, and the aluminum workpiece being degreased before it is immersed into the plating bath, and the plating operation being carried out in the presence of a source of fluoride ions which consists of ammonium or potassium fluorides or bifluorides and is present in the bath in concentrations of 0.1 to 10 grams per litre.
Claim 16
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of triethylamine and 100 ml/1 of ammonium hydroxide of 30% concentration and has a pH of about 9.5, and the plating is carried out in a current density range of 80 - 250 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 17
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of triethanolamine and 200 m/1 of ammonium hydroxide of 30% concentration and has a pH of about 9 and the plating is carried out in a current density range of 115 - 300 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 18
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of diethylenetriamine and 100 ml/1 of ammonium hydroxide of 30% concentration and has a pH of about 10.7, and the plating is carried out in a current density range of 10 - 200 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 19
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of tetraethylenepentamine and 100 ml/1 of ammonium hydroxide of 30% concentration and has a pH of about 10, and the plating is carried out in a current density range of 5 - 85 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 20
Dependent Claim
76 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of tetraethylenepentamine, 12 g/1 of ammonium nitrate and an amount of ammonium hydroxide of 30% concentration sufficient to make the bath of a pH of about 10, and the platIng is carried out in a current density range of 10 - 200 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 21
Dependent Claim
76 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 150 g/1 of tetraethylenepentamine, 50 g/1 of ammonium citrate and an amount of ammonium hydroxide of 30% concentration sufficient to make the bath of a pH of about 10, and the plating is carried out in a current density range of 10 - 210 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 22
Dependent Claim
76 words
Method as claimed in claim 1, in which the plating bath comprises 150 g/1 of copper nitrate, 120 g/1 of tetraethylenepentamine, 50 g/1 of sodium chloride and an amount of ammonium hydroxide of 30% concentration sufficient to make the bath of a pH of about 10, and the plating is carried out in a current density range of 5 - 100 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 23
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 250 g/1 of copper nitrate, 250 g/1 of tetraethylenepentamine and 165 ml/1 of ammonium hydroxide of 30% concentration and has a pH of about 10.8, and the plating is carried out in a current density range of 5 - 100 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
Claim 24
Dependent Claim
67 words
Method as claimed in claim 1, in which the plating bath comprises 450 g/1 of copper nitrate, 450 g/1 of tetraethylenepentamine and 450 m/1 of ammonium hydroxide of 30% concentration and has a pH of about 11.6, and the plating is carried out in a current density range of 5 - 120 amperes per square foot for a time sufficient to achieve a plating of predetermined thickness.
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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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |