| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve the problem that conventionally deterioration in the wettability and jointing property of solder to a wiring layer, peel-off and blister in a plating layer, or the like occurs in the case of solder connection. SOLUTION: On the surface of a region, where the electrode of at least electronic components 3 in the wiring layer 2 is connected via a soldering ball 5, a nickel-boron-plated layer 6, a nickel-plated layer 7 with the content of nickel being 99.9 wt.% or more, and at the same time the average particle size of a nickel particle is being 20 nm or larges, a palladium or palladium alloy-plated layer 8, and a gold-plated layer 9 are successively deposited by the electroless method. The nickel-plated layer 7 restrains the formation of a nickel oxide layer onto the surface of the gold-plated layer 9, thus maintaining high wettability and bonding property to the wiring layer. In addition, the palladium or palladium alloy-plated layer 8 prevents voids and gaps from forming between the nickel- and gold-plated layers, thus preventing peel-off and blister.</p> |
