| abstract |
Provided is a tin or tin-alloy plating solution containing (A) a soluble salt comprising a stannous salt, (B) an acid selected from among organic acids and inorganic acids, or a salt thereof, (C) a surfactant, (D) benzalacetone, and (E) a solvent, wherein: the plating solution is used for forming, on a base material, a pattern having different bump diameters; the amount of (D) benzalacetone is 0.05 g/L to 0.2 g/L; the mass ratio (C/D) of (C) the surfactant to (D) benzalacetone is 10-200; and the mass ratio (E/D) of (E) the solvent to (D) benzalacetone is 10 or higher. |