| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming bump on circuit board by which a bump can be formed on a circuit board with a desired height. SOLUTION: In this method, the bump is formed on the circuit board in such a way that, even when a via hole has a large aspect ratio, the aspect ratio is virtually reduced by raising the bottom of the via hole by plating in a first stage, and then, the bump 4 is formed in a desired shape in a second stage. At the time of forming the bump 4 in the via hole having the large aspect ratio by means of a plating means, the bump 4 is formed in the desired shape by changing the concentration of an additive in a plating bath in accordance with the plated thickness of the bump 4.
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