Palladium plating solution and plating method

Patent metadata

Field	Value
Publication number	US-11814717-B2
Application number	US-202117219709-A
Country	US
Kind code	B2
Filing date	Mar 31, 2021
Priority date	Apr 3, 2020
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

The purpose of the present invention is to provide a palladium plating solution and a plating method for improving a bath stability of a palladium plating, without decreasing a deposition property of the palladium plating. A palladium plating solution for improving a bath stability, without decreasing a deposition property, comprising: an aqueous palladium compound: one or more complexing agent containing a compound having at least an ethylenediamine or a propylenediamine skeleton; a formic acid or a formate; and a sulfur compound, wherein the palladium plating solution is having two or more sulfide groups in a molecule of the sulfur compound.

First claim

The invention claimed is:

1. A palladium plating solution for improving a bath stability, without decreasing a deposition property, comprising:
an aqueous palladium compound;
one or more complexing agent containing a compound having at least an ethylenediamine or a propylenediamine skeleton;
formic acid or a formate; and
a sulfur compound, wherein a concentration of the sulfur compound is between 0.01 mg/L to 0.8 mg/L, inclusive of the range endpoints, and
wherein the sulfur compound has two or more sulfide groups in a molecule.

2. The palladium plating solution according to claim 1 , wherein the sulfur compound is a compound represented by a general formula in below:
R1—(CH 2 ) x —S—(CH 2 ) y —S—(CH 2 ) z —R2

wherein x=1 to 4, y=1 to 3, z=1 to 4,
R1 or R2 is a functional group selected from a group consisting of —OH, —COOH, and —CN.

3. The palladium plating solution according to claim 1 , wherein a concentration of the sulfur compound is 0.01 mg/L to 0.7 mg/L, inclusive of the range endpoints.

4. The palladium plating solution according to claim 1 , wherein a concentration of the complexing agent is 0.5 g/L to 25 g/L.

5. The palladium plating solution according to claim 1 , wherein the complexing agent is one or more compounds having at least an ethylenediamine or a propylenediamine represented by a general formula in below:

where:
n, m, 1=2 or 3
R 1 or R 2 or R 3 or R 4 or R 5 or R 6 is selected from a group consisting of —H, —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 —OH, and —CH 2 COOH.

6. A plating method using a palladium plating solution for improving a bath stability, without decreasing a deposition property, comprising a palladium plating step comprising applying a palladium plating solution of claim 1 on to a surface of an underlying metal.

7. The plating method according to claim 6 , wherein the underlying metal is a gold, a nickel, a palladium, a copper, or an alloy thereof, or a combination thereof.

Assignees

• Uemura Kogyo Kk

Inventors

• Kaneko Yohei
• Oogami Yuhei
• Tanabe Katsuhisa
• Maeda Tsuyoshi

Classifications

• C23C18/44 Primary

  using reducing agents · CPC title

• B32B15/018

  one layer being formed of a noble metal or a noble metal alloy · CPC title

• C08K3/11

  Compounds containing metals of Groups 4 to 10 or of Groups 14 to 16 of the Periodic Table · CPC title

• C08K5/09

  Carboxylic acids; Metal salts thereof; Anhydrides thereof · CPC title

• C08K5/17

  Amines; Quaternary ammonium compounds · CPC title