Electroplating solutions
AssigneeJohnson Matthey Public Limited Company
InventorAlan Boardman
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Abstract
The invention relates to an 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.
Claims17
An electroplating bath comprising a cathode and an anode which are both at least partially submerged in an electrolyte, wherein the electrolyte is an aqueous electroplating solution comprising
- [Pt(NH3)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.
A method of forming a metal layer on a substrate by electroplating, wherein electroplating is carried out using a bath comprising a cathode and an anode which are both at least partially submerged in an electrolyte, wherein the electrolyte is an aqueous electroplating solution comprising
- [Pt(NH3)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.
Dependencies are inferred from the claim text.