| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface treating method for a flexible wiring board, which employs a metal not containing lead and tin, offers fine solder wettability, and allows inexpensive and reliable surface treatment. SOLUTION: Wires are arranged at a given pitch on a flexible board to form a wiring part 6, on which a nickel plating 2 is formed by an electrolytic plating process. The nickel plating 2 is then coated with a palladium-strike plating 3, which is further coated with a gold-lap plating 4. The palladium-strike plating 3 and the gold-lap plating 4 are formed by the electrolytic plating process using the currents corresponding to the pitch of wiring, so that the thickness of the palladium-strike plating 3 is within a range of 0.007 to 0.1μm, and the same of the gold-lap plating 4 is within a range of 0.003 to 0.02μm, and the gold-lap plating 4 is thinner than the palladium-strike plating 3. COPYRIGHT: (C)2006,JPO&NCIPI
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