| 摘要 |
PROBLEM TO BE SOLVED: To coat the surfaces of narrow-plane-area connection pads with a nickel plated layer and a gold plated layer of uniform thickness. SOLUTION: A wiring substrate 5 comprises an insulating base substrate 1, wiring conductors 2 formed on the surface and/or inside of the insulating base substrate 1, and connection pads 3 formed on the surface of the insulating base substrate 1 and electrically connected to the wiring conductors 2. Each connection pad 3 has a plane area of 0.58 mm2 or smaller, and its surface is sequentially coated with a nickel plated layer 7 containing boron of 0.05-3 wt.%, sulfur of 0.005-0.08 wt.%, and at least one among bismuth, selenium, and tellurium of 0.008-0.2 wt.%, and a gold plated layer 8. |
