To provide a method for producing a microstructure without using a matrix while using a plating process, and the microstructure produced by the method.
Plating is performed by using an acidic tin-based plating solution which includes a water-soluble stannous-containing material, a water-soluble copper-containing material, at least one of a sulfate ion and a sulfonate ion, an organic complex agent, and a nonionic surfactant, plating temperature of 60°C or less, current density of 10 A/dm2 or less, and an integrated current amount of 500 Asec/dm2 or more, so that a tin-based plated structure, which includes a generally laminar film portion and a plurality of protruding portions, each protruding from the surface of the film portion and having a cone shape, is obtained without using a matrix for the protruding portion. The protruding portion has an aspect ratio, a ratio of the height thereof to the diameter of the bottom surface thereof when converted to a circle, of 0.5 or more. The density of the protruding portions on the film portion is 100 pieces or more per 1 mm2 projected area of the film portion.
Katsuyuki Okubo
Keisuke Murasame