| abstract |
(57) [Summary] [Objective] To provide an improved tin-bismuth alloy electroplating bath. [Structure] This plating bath is a cationic solution together with a nonionic surfactant in an aqueous solution containing a soluble stannous compound, a soluble bismuth compound, and an acid in an amount sufficient to prevent hydrolysis thereof. At least one kind of surfactant selected from the group of surfactants, anionic surfactants and amphoteric surfactants is added. [Effect] Surface particles are dense and have a good appearance, good heat resistance, steam aging resistance and solderability, and a plating film with high cathode current density and no rough electrodeposition (burning) is obtained. be able to. |