| 摘要 |
A cyanide-free immersion type electroless gold plating solution that is less toxic, that can be used at near neutrality, and that gives an excellent and improved solder adhesion and plated film adhesion is provided. An electroless gold plating solution, comprising a cyanide-free water-soluble gold compound, a pyrosulfurous acid compound and a thiosulfuric acid compound. This plating solution preferably further contains a sulfurous acid compound and an aminocarboxylic acid compound. Pyrosulfurous acid and alkali metal salts, alkaline-earth metal salts, ammonium salts and other salts thereof can be used as the pyrosulfurous acid compound.
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