Electroless gold plating solution

Abstract

There is provided a cyanide-free immersion type electroless gold plating liquid that is low in toxicity, can be used near neutral, and has good solder adhesion and plating film adhesion. An electroless gold plating liquid containing a cyanide-free water-soluble gold compound and a pyrosulfurous acid compound. The plating liquid may further contain a sulfurous acid compound and an aminocarboxylic acid compound. Pyrosulfurous acid or an alkali metal, alkaline earth metal, ammonium, or other such salt thereof can be used as the pyrosulfurous acid compound.

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