Patent ID: 8124174

Claim:
A method for forming an electroless gold plating film of a plated film laminate comprising: forming, on a surface to be plated of an electronic part being a printed circuit board, a ceramic substrate or a semiconductor substrate, a 0.1 to 20 μm thick of electroless nickel plating film through a catalyst; forming a 0.001 to 0.3 μm thick of electroless palladium plating film on said electroless nickel plating film; and forming a 0.01 to 1.0 μm thick of electroless gold plating film on said electroless palladium plating film, wherein part or whole of said electroless gold plating film is formed by a first electroless gold plating using an electroless gold plating bath comprising a water-soluble gold compound, a complexing agent, formaldehyde and/or a formaldehyde-bisulfite adduct, and an amine compound represented by the following general formula (1) or (2) R 1 —NH—C 2 H 4 —NH—R 2 (1) R 3 —(CH 2 —NH—C 2 H 4 —NH—CH 2 ) n —R 4 (2) wherein R 1 and R 3 represent —OH, —CH 2 OH, —C 2 H 4 OH, —CH 2 N(CH 3 ) 2 , —CH 2 NH(CH 2 OH), —CH 2 NH(C 2 H 4 OH), —C 2 H 4 NH(CH 2 OH), —C 2 H 4 NH(C 2 H 4 OH), —CH 2 N(CH 2 OH) 2 , —CH 2 N(C 2 H 4 OH) 2 , —C 2 H 4 N(CH 2 OH) 2 or —C 2 H 4 N(C 2 H 4 OH) 2 and may be the same or different, R 2 , and R 4 represent —OH, —CH 3 , —CH 2 OH, —C 2 H 4 OH, —CH 2 N(CH 3 ) 2 , —CH 2 NH(CH 2 OH), —CH 2 NH(C 2 H 4 OH), —C 2 H 4 NH(CH 2 OH), —C 2 H 4 NH(C 2 H 4 OH), —CH 2 N (CH 2 OH) 2 , —CH 2 N(C 2 H 4 OH) 2 , —C 2 H 4 N(CH 2 OH) 2 or —C 2 H 4 N(C 2 H 4 OH) 2 and may be the same or different, and n is an integer of 1 to 4.