| 摘要 |
PROBLEM TO BE SOLVED: To obtain a wiring board with which a solder bonding operation of high connection reliability is obtained by a method, wherein impurities which obstruct a bonding operation to solder are removed from the region of a nickel- plated film which forms an alloy with the solder. SOLUTION: On an insulating board 4, which contains a copper layer as the uppermost wiring pattern of a multilayer wiring board, the whole face which excludes the external connecting-terminal formation region of a copper layer 3 is coated with a solder-resist insulating layer 2. While the insulating layer 2 is used as a mask, an electroless nickel-plated layer 1 is formed on the exposed copper layer 3. Then, the surface layer part of the nickel-plated layer 1 is etched, and impurities which obstruct a connection to solder are melted and removed selectively. Consequently, a nickel-plated layer 5 not containing the impurities which obstruct the connection to the solder is formed on the surface layer part of the nickel-plated layer 1. An actual external connecting terminal is constituted, a gold plating operation which ensures the prevention of oxidation, and the wettability of solder is executed to the nickel- plated layer 5 which does not contain the impurities.
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