| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer wiring board having interlayer connections by a low resistance via hole conductor ensuring high connection reliability capable of satisfying the need for Pb free.SOLUTION: Wirings are formed of a copper foil disposed via an insulating resin layer. Via hole conductors are formed to go through the insulating resin layer to electrically connect plural wirings. The via hole conductor has a resin portion and a metal portion including copper, tin and bismuth. The metal portion includes: a first metal region containing a combination of copper particulates; a second metal region containing as a main element at least any one of tin, tin-copper alloy, and intermetallic compound of tin and copper; and a third metal region mainly containing bismuth. The surface of the copper foil in contact with the via hole conductor is a rough surface with skewness of roughness curve of 0 or less. A part of copper particulates is in surface contact with rough surface of the copper foil, and the at least a part of second region is formed on the surface of the combination and the rough surface of the copper foil. |
