| 摘要 |
PROBLEM TO BE SOLVED: To obtain a plating liquid with decreased toxicity which keeps good pattern plating property and which enables stable and thick plating for a long time by adding compds. IIIb, Vb elements to a catalyst-type plating liquid containing gold salts, complexing agent, reducing agent, pH buffer or the like without incorporating cyanide compds. SOLUTION: A catalyst-type electroless gold plating liquid without containing cyanide compds. is prepared by incorporating gold salts such as gold sodium sulfite and sodium chloroaurate by about 1 to 10 g/L calculated in terms of gold ion, complexing agent such as sodium thiosulfate and sodium sulfite by about 5 to 100 g/L, reducing agent such as thiourea by about 0.5 to 5 g/L, and pH buffer such as sodium tetraborate by about 5 to 60 g/L. Further, compds. of IIIb, Vb elements are incorporated as additives by about 1×10-3 to 1 g/L to the plating liquid. The IIIb elements are preferably Ga and In, and the Vb elements are preferably Sb and Bi. The additives produce S ion and insoluble compd. from the sulfite ion to prevent decomposition of the plating liquid or failure in plating precipitation.
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