| 摘要 |
PURPOSE: To prevent the whiskering of a tin plating film in the case of plating a fine pattern of copper, etc., with tin without need for annealing, etc., while keeping the bonding strength between the tin plating and the gold bumping electrode of a semiconductor chip. CONSTITUTION: A tin plating bath contg. the soluble metallic salt prepared by adding a salt of a low-m.p. metal such as bismuth, indium, lead or antimony is used to form a tin plating film on a fine pattern so that the content of the low-m.p. metal in the deposited film is controlled to 0.1-3.0wt.% and the thickness to 0.1-1.0μm. Since the tin film having a low content of a specified trace metal is deposited in a specified thickness, annealing, etc., are not needed, and a whiskering preventive effect and a high bonding strength are attained.
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