| 摘要 |
PROBLEM TO BE SOLVED: To stabilize a plating liquid and to increase the precipitation rate of a gold plating film of high purity by compounding a specified amt. of lithium compds. into an alkaline self-catalyst type plating liquid having specified cyanide concn. and pH and containing a specified amt. of gold compds. and reducing agent. SOLUTION: A lithium compd. is compounded in a self-catalyst type alkaline electroless gold plating liquid containing cyanide compds. to prepare a liquid containing 0.2 to 20 g/L gold compd. (calculated in terms of gold ion concn.), 1 to 50 g/L reducing agent, and 0.1 to 100 g/L lithium compd., preferably 0.1 to 70 g/L, and having 0.1 to 20 g/L isolated cyanide concn. and pH 10 to 14. The gold compd. is gold (I) potassium cyanide or the like, the reducing agent is dimethylamine borane or the like, and the lighium compd. is lighium oxalate or the like. If necessary, the electroless gold plating liquid may contain 0.1 to 50 mg/L of thallium compd. or lead compd., and further 0.1 to 80 g/L of stabilizer.
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