Pyrophosphate-containing bath for cyanide-free deposition of copper-tin alloys

Patent metadata

Field	Value
Publication number	US-9399824-B2
Application number	US-201314100633-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	Jun 2, 2008
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

A pyrophosphate-containing bath for the cyanide-free deposition of copper alloys on substrate surfaces, comprising a reaction product of a secondary monoamine with a diglycidyl ether, is described. The electrolyte bath is suitable for the galvanic deposition of glossy white, even and uniform copper-tin alloy coatings.

First claim

The invention claimed is:

1. A method for the galvanic deposition of glossy and even copper-tin alloy coatings, comprising (i) introducing a substrate to be coated into an aqueous cyanide-free pyrophosphate-based electrolyte bath and (ii) galvanically depositing a copper-tin alloy coating on the substrate,
wherein the bath has a pH of 3 to 9 and comprises water-soluble copper salts, water-soluble tin salts, a reaction product of a secondary monoamine with a diglycidyl ether and 0.1 to 50 g/l of N-methylpyrrolidone,
wherein the secondary monoamine is morpholine and the diglycidyl ether is selected from the group consisting of glycerol diglycidyl ether, poly(propylene glycol) diglycidyl ether, poly(ethylene glycol) diglycidyl ether and mixtures thereof.

2. The method according to claim 1 , wherein the diglycidyl ether is glycerol diglycidyl ether.

3. The method according to claim 1 , wherein the molar ratio of diglycidyl ether to secondary monoamine is 0.8 to 2.

4. The method according to claim 3 , wherein the molar ratio of diglycidyl ether to secondary monoamine is 0.9 to 1.5.

5. The method according to claim 1 , wherein the reaction product is contained in the bath in a concentration of 0.0001 to 20 g/l.

6. The method according to claim 5 , wherein the reaction product is contained in the bath in a concentration of 0.001 to 1 g/l.

7. The method according to claim 1 , wherein the bath further comprises an additive selected from the group consisting of orthophosphoric acid, an organic sulfonic acid, boric acid, an antioxidant agent and an organic brightener.

8. The method according to claim 1 , wherein the N-methylpyrrolidone is contained in the bath in a concentration of 0.5 to 15 g/l.

9. The method according the claim 1 , wherein the bath has a pH value of 6 to 8.

10. The method according to claim 1 , wherein the bath is operated at a set current density of 0.01 to 2 A/dm 2 .

11. The method according to claim 10 , wherein the bath is operated at a set current density of 0.25 to 0.75 A/dm 2 .

12. The method according to claim 1 , wherein the bath is operated at a temperature of 15 to 50° C.

13. The method according to claim 12 , wherein the bath is operated at a temperature of 20 to 30° C.

14. The method according to claim 1 , wherein membrane anodes are used as anodes in the step of galvanically depositing the copper-tin alloy coating on the substrate.

Assignees

• Atotech Deutschland Gmbh

Inventors

• Hartmann Philip
• Schulz Klaus-Dieter
• Kohlmann Lars
• Brunner Heiko

Classifications

• C25D3/60

  containing more than 50% by weight of tin · CPC title

• C25D3/58 Primary

  containing more than 50% by weight of copper · CPC title