Abstract: A gold plating solution containing a gold cyanide salt, a reducing agent that is formaldehyde or its precursor, and an iron cyanide compound, and not containing a chelate compound having two or more iminodiacetic acid groups or aminomethylenephosphonic acid groups, is brought into contact with a chelating resin having an iminodiacetic acid group or an aminomethylenephosphonic acid group, thereby removing iron ions from the gold plating solution.

Abstract: The present invention provides an electroless gold plating bath having excellent plating bath stability without containing a cyanide compound under long term plating bath heating time. An electroless gold plating bath of the present invention solving above problems includes: a water-soluble gold salt; a reducing agent; and a phosphine compound represented by a following formula (1) wherein R1, R2, and R3 represent identically or differently either a phenyl group, or an alkyl group having 1 to 5 carbons, and at least one of the phenyl group or the alkyl group is substituted by a sulfonate group or its salt, a cyano group, or a carboxy group or its salt.

Abstract: A film formation method is provided with a catalyst film formation step for forming a catalyst film on the surface of a substrate by displacement reduction plating, an intermediate film formation step for forming a palladium plating film on the catalyst film, and a surface film formation step for forming a gold plating film on the palladium plating film.

Abstract: The purpose of the present invention is to provide a gold plating method and a plating film for preventing a decrease of wire bonding characteristic by a thermal hysteresis by implementation and else. In addition, the purpose of the present invention is to provide a gold plating method and a plating film for preventing a decrease of wire bonding characteristic by a thermal hysteresis by implementation and else, even when a film thickness of a gold plating film is thin. A gold plating method for wire bonding connection by plating using a silver catalyst on a copper or copper alloy film, comprising: a silver catalyst forming step for forming a silver film as the silver catalyst for forming a palladium film; a palladium film forming step for forming the palladium film on the silver catalyst; a gold plating film forming step for forming a gold plating film on the palladium film, wherein a film thickness of the silver film is 0.05 ?m to 0.5 ?m.

Abstract: The present invention provides an electroless gold plating bath having excellent plating bath stability without containing a cyanide compound under long term plating bath heating time. An electroless gold plating bath of the present invention solving above problems includes: a water-soluble gold salt; a reducing agent; and a phosphine compound represented by a following formula (1) wherein R1, R2, and R3 represent identically or differently either a phenyl group, or an alkyl group having 1 to 5 carbons, and at least one of the phenyl group or the alkyl group is substituted by a sulfonate group or its salt, a cyano group, or a carboxy group or its salt.

Abstract: A film formation method is provided with a catalyst film formation step for forming a catalyst film on the surface of a substrate by displacement reduction plating, an intermediate film formation step for forming a palladium plating film on the catalyst film, and a surface film formation step for forming a gold plating film on the palladium plating film.