| abstract |
(57) [Problem] To improve the appearance of an electrodeposition film and solder wettability by adding a specific additive to a tin, lead or tin-lead alloy plating bath. SOLUTION: (A) a soluble metal salt comprising a stannous salt, a lead salt, and a mixture of a stannous salt and a lead salt; Tin containing a specific linear aliphatic hydrocarbon compound in which an ethylene oxide, propylene oxide or hydroxypropylene oxide group is present singly or repeatedly in a molecule, essentially adjacent to one or both sides of a mono- or disulfide bond; It is a lead and tin-lead alloy plating bath. Since the specific linear aliphatic hydrocarbon compound is contained, the uniformity, denseness, color tone, or solder wettability of the plating film is improved over a wide pH range from acidic to weakly alkaline. |