| abstract |
Part or whole of an electroless gold plating film of a plated film laminate including an electroless nickel plating film, an electroless palladium plating film and an electroless gold plating film is formed by an electroless gold plating using an electroless gold plating bath including a water-soluble gold compound, a completing agent, formaldehyde and/or a formaldehyde-bisulfite adduct, and an amine compound represented by the following general formula R 1 —NH—C 2 H 4 —NH—R 2 or R 3 —(CH 2 —NH—C 2 H 4 —NH—CH 2 ) n —R 4 . The method of the invention does not need two types of baths, a flash gold plating bath and a thick gold plating bath for thickening. Gold plating films of different thicknesses suited for solder bonding or wire bonding can be formed using only one type of gold plating bath. Especially, an electroless gold plating film having a thickness of not smaller than 0.15 μm can be efficiently, effectively formed by use of one plating bath in one step, thereby enabling the process to be simplified along with an attendant advantage in cost. |