Electrolytic gold plating solution

Abstract

To provide an electrolytic gold plating solution that can stably exhibit good selective gold deposition properties during gold plating. [Solution] The electrolytic gold plating solution of the present invention contains a gold source and an oxidizing agent (specific oxidizing agent) that exhibits a reaction potential above a specific value when linear sweep voltammetry is performed under specific conditions. Furthermore, in the electrolytic gold plating solution of the present invention, the concentrations of copper ions and lead ions are below a specific value. The specific oxidizing agent has the effect of improving the selective deposition of gold in the electrolytic gold plating solution. However, if copper ions or lead ions are mixed into the electrolytic gold plating solution, the effect of the specific oxidizing agent in improving the selective deposition of gold is inhibited. In the electrolytic gold plating solution of the present invention, the concentrations of copper ions and lead ions are kept low, so the selective deposition effect of gold by the specific oxidizing agent is not inhibited and is fully exerted.

Claims

1. An electrolytic gold plating solution containing a gold source and an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7V or higher, An electrolytic gold plating solution characterized by having a copper ion concentration of less than 20 ppm. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

2. An electrolytic gold plating solution containing a gold source and an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7V or higher, An electrolytic gold plating solution characterized by having a lead ion concentration of less than 10 ppm. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

3. The electrolytic gold plating solution according to claim 1, which contains one or more metal salts selected from the group consisting of cobalt salts, nickel salts, iron salts, and silver salts.

4. The electrolytic gold plating solution according to claim 2, which contains one or more metal salts selected from the group consisting of cobalt salts, nickel salts, iron salts, and silver salts.

5. The electrolytic gold plating solution according to claim 1, wherein the gold source is one or more gold sources selected from the group consisting of gold(I) cyanide, gold(III) cyanide, potassium gold(I) cyanide, potassium gold(III) cyanide, sodium gold(I) cyanide, sodium gold(III) cyanide, potassium gold sulfite, and sodium gold sulfite.

6. The electrolytic gold plating solution according to claim 2, wherein the gold source is one or more gold sources selected from the group consisting of gold(I) cyanide, gold(III) cyanide, potassium gold(I) cyanide, potassium gold(III) cyanide, sodium gold(I) cyanide, sodium gold(III) cyanide, potassium gold sulfite, and sodium gold sulfite.

7. The electrolytic gold plating solution according to claim 1, wherein the oxidizing agent is one or more oxidizing agents selected from the group consisting of nitro compounds, peroxides, and iodates.

8. The electrolytic gold plating solution according to claim 2, wherein the oxidizing agent is one or more oxidizing agents selected from the group consisting of nitro compounds, peroxides, and iodates.

9. A composition for preparing an electrolytic gold plating solution, for preparing an electrolytic gold plating solution according to any one of claims 1 to 8 by adding a gold source, characterized in that it contains an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7 V or higher. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

10. A gold selective deposition enhancer for preparing an electrolytic gold plating solution according to any one of claims 1 to 8, characterized in that it mainly comprises an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7 V or higher. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

11. A method for producing an electrolytic gold plating solution, characterized by supplying components to the aging solution of the electrolytic gold plating solution according to any one of claims 1 to 8.

12. The electrolytic gold plating solution preparation method according to claim 11, wherein the electrolytic gold plating solution preparation composition is replenished in the aging solution and contains an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7 V or higher. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

13. A gold selective deposition enhancer for a method of producing an electrolytic gold plating solution according to claim 11, characterized in that the gold selective deposition enhancer supplied to the aging solution mainly comprises an oxidizing agent whose reaction potential obtained when linear sweep voltammetry is performed under the following measurement condition A is -0.7 V or higher. <Measurement Condition A> A test solution was prepared by dissolving 40 g / L of citric acid and 60 g / L of tripotassium citrate in water to form a base solution, to which the oxidizing agent was added to a concentration of 10 mmol / L. Potassium hydroxide or citric acid was then added to adjust the pH to 4.2 at 25°C. Using this test solution as the electrolyte, an Au electrode was used as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Under conditions of 50°C, the system was scanned at an initial potential of 1.0 V, a final potential of -3.0 V, and a speed of 0.1 V / s. The potential at which the current value became -0.05 mA was defined as the reaction potential.

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