PURPOSE: To prevent passivation of a plated layer, and to improve the close contactness between plated layers by a method wherein the plated surface is treated with a specific aqueous solution while each non-electrolytic plating treatment is being conducted.
CONSTITUTION: In the printed-wiring-board manufacturing method in which a non-electrolytic plating treatment is conducted by dividing it into two or more times, the surface of plating is treated by the aqueous solution of pH 2 to 7, containing a cyanic compound, between each non-electrolytic treatment. When the aqueous solutions, pH is lower than 2, hydrogen cyanide is generated, and when the pH is higher than 8, the degree of removing action of an oxide film is decreased. As the cyanic compound has a strong chelate action with metal, the grown oxide film can be removed by treating the surface with the above-mentioned aqueous solution after a strike plating operation is finished. Also, after treatment, the cyanic compound is brought into the state wherein it is adsorbed to the plated layer, an oxide film is not grown even when the plated layer is exposed to atmospheric air before the plating work to be followed is conducted.
KOUCHI SHIGERU
SEKIGUCHI KUNIAKI
