WIRING SUBSTRATE, METHOD FOR MANUFACTURING WIRING SUBSTRATE, AND VIA PASTE

摘要

Disclosed is a multilayer wiring board having via-hole conductors, the via-hole conductor including a metal portion and a resin portion. The metal portion includes a first metal region which includes a link of copper particles forming a path electrically connecting a first wiring and a second wiring; a second metal region mainly composed of a metal selected from the group consisting of tin, a tin-copper alloy, and a tin-copper intermetallic compound; a third metal region mainly composed of bismuth; and a fourth metal region composed of tin-bismuth solder particles. The link has plane-to-plane contact portions where the copper particles are in plane-to-plane contact with one another. At least a part of the second metal region is in contact with the first metal region. The tin-bismuth solder particles, each surrounded by the resin portion, are interspersed in the via-hole conductor.