| 摘要 |
PROBLEM TO BE SOLVED: To obtain a uniform acicular copper coating excellent in adhesiveness by carrying out electroplating using a plating solution prepared by adding a transition metallic element and a sulfur compound. SOLUTION: A transition metallic element and a sulfur compound are added to an acidic copper plating solution to prepare the objective copper electroplating solution. A copper sulfate plating solution or a copper pyrophosphate plating solution is used as the acidic copper plating solution. The transition metallic element is, e.g. a group VIII element such as Ni, Fe or Co and is preferably added by about 200-10,000 mg/l. The sulfur compound is, e.g. thiosulfuric acid or a thiosulfate such as sodium thiosulfate, potassium thiosulfate, calcium thiosulfate, iron thiosulfate or copper potassium thiosulfate and is preferably added by about 100-10,000 mg/l. A copper coating of about >=0.2μm thickness is required so as to obtain a copper coating having uniform acicular crystals and plating time is preferably >=1 min.
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