Electroplating solutions

Patent metadata

Field	Value
Publication number	US-2025305175-A1
Application number	US-202519235940-A
Country	US
Kind code	A1
Filing date	Jun 12, 2025
Priority date	Dec 18, 2020
Publication date	Oct 2, 2025
Grant date	—

Abstract

Aqueous electroplating solution for alkaline electroplating, comprising: [M(NH3)4]2+ ions, wherein M is selected from the group consisting of Pd or Pt; and organic anions selected from the group consisting of bicarbonate, carbonate, or a mixture thereof; wherein the following species, if present, are present in the following amounts: alkali metals in an amount of less than 5 g/L; compounds comprising phosphorus in an amount of less than 5 g/L; compounds comprising boron in an amount of less than 5 g/L. The invention also relates to an electroplating bath comprising the electroplating solution, and a method of forming a metal layer on a substrate by electroplating using the electroplating solution.

First claim

What is claimed:

1 . An aqueous electroplating solution for alkaline electroplating, comprising:
[Pt(NH 3 ) 4 ] 2+ ions; and organic anions selected from the group consisting of bicarbonate, carbonate, or a mixture thereof;
wherein the molar ratio of Pt: (bicarbonate+carbonate) is approximately 1:2; and
wherein the following species, if present, are present in the following amounts:
alkali metals in an amount of less than 5 g/L;
compounds comprising phosphorus in an amount of less than 5 g/L;
compounds comprising boron in an amount of less than 5 g/L.

2 . The aqueous electroplating solution according to claim 1 , wherein the concentration of Pt in the solution is 1 to 30 g/litre, on a metal basis.

3 . The aqueous electroplating solution according to claim 1 , wherein the concentration of Pt in the solution is 5 to 30 g/litre, on a metal basis.

4 . The aqueous electroplating solution according to claim 1 , wherein the concentration of Pt in the solution is 5 to 25 g/litre, on a metal basis.

5 . The aqueous electroplating solution according to claim 1 , wherein the pH of the solution is 8 to 14.

6 . The aqueous electroplating solution according to claim 1 , comprising a pH adjusting agent selected from the group consisting of ammonia, urea, an alkylammonium hydroxide, ammonium hydroxide, ammonium bicarbonate and ammonium carbonate.

7 . The aqueous electroplating solution according to claim 1 , wherein the content of alkali metals is less than 0.1 g/L.

8 . The aqueous electroplating solution according to claim 1 , wherein the content of halide ions in the electroplating solution is less than 1 g/L.

9 . The aqueous electroplating solution according to claim 1 , wherein the content of nitrite ions in the electroplating solution is less than 0.5 g/L.

10 . The aqueous electroplating solution according to claim 1 , wherein the content of nitrate ions in the electroplating solution is less than 0.5 g/L.

11 . The aqueous electroplating solution according to claim 1 , wherein the content of compounds containing silicon is less than 0.5 g/L.

12 . The aqueous electroplating solution according to claim 1 , wherein the content of compounds containing sulfur is less than 0.5 g/L.

Assignees

• Johnson Matthey Plc

Inventors

• Boardman Alan

Classifications

• C25D3/50 Primary

  of platinum group metals · CPC title

• C25D7/005

  Jewels; Clockworks; Coins · CPC title

• C25D3/52 Primary

  characterised by the organic bath constituents used · CPC title