| 摘要 |
PURPOSE:To obtain the title reflow tin plating material having excellent appearance, corrosion resistance, and solderability, by using a tin plating bath contg. a specified org. acid as the free acid, and carrying out electroplating at a specified anode current density when a strip of copper or a copper alloy is plated with tin and reflow-treated. CONSTITUTION:The surface of copper or a copper alloy such as phosphor bronze is plated with tin and reflow-treated to produce a reflow tin plating material. In this case, an org. acid such as phenol sulfonic acid, and an alkane sulfonic acid is incorporated as a free acid into the tin plating soln. contg. tin sulfate, tin phenol sulfonate, etc., as a stannous ion source, and 1-30g/l 1 or >=2 kinds of surfactants shown by formula I-VIII is added to the soln. The cathode current density DK in plating is controlled to 10-50A/dm<2>, and the temp. T of the plating soln. and the current density DK are limited to conform to the relation shown by equation IX. As a result, a reflow tin plating material having an excellent characteristic after being reflow-treated can be obtained.
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