| abstract |
A Sn-Bi alloy plating bath comprises at least one compound selected from the group consisting of polyoxy monocarboxylic acids, polyoxy lactones, polycarboxylic acids and salts thereof. A plating method comprises the step of applying a Sn-Bi alloy plating film to a substrate in the foregoing plating bath. The plating bath permits the formation of a Sn-Bi alloy plating film having a bismuth content ranging from 0.1 to 75% over a wide current density range. Moreover, the plating bath never forms precipitates, does not become turbid, does not cause any change of the bath composition and is, therefore, quite stable even when it is stored over a long period of time. |