| 摘要 |
PROBLEM TO BE SOLVED: To improve the adhesive strength between an electroless nickel plating film and solder at the time of soldering and to improve the yield in the soldering stage by specifying the ten point average roughness of the surface of an electroless nickel plating substrate film formed on a stock in which an electroless gold plating film formed. SOLUTION: An electroless nickel plating substrate is formed on a stock, and, an electroless gold plating film is formed on the electroless nickel plating substrate. At this time, the ten point average roughness of the surface of the electroless nickel plating film to be formed on the stock is controlled to 0.5 to 1.5μm. Moreover, the thickness of the electroless nickel plating film to be formed on the stock is preferably controlled to 7 to 15μm. Furthermore, the electroless nickel plating film can be formed on the stock with an electroless nickel plating soln., as a reducing agent, using sodium hypophosphite added with 0.01 to 0.05 mL/L sulfur compd. as a stabilizer. Moreover, by executing chemical or mechanical polishing, the ten point average roughness of the surface can be controlled to the range.
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