Wiring board and mounting structure using the wiring board

Abstract

A wiring board according to the present disclosure includes: a first insulation layer having a first surface; a land conductor located on the first surface; a second insulation layer covering the first surface and the land conductor and having a second surface on a side opposite to the first insulation layer; a via hole penetrating from the second surface of the second insulation layer to the land conductor; and a via hole conductor located in the via hole and in contact with the land conductor. The via hole conductor includes an underlying metal layer and an electrolytic plating layer located on the underlying metal layer, the underlying metal layer being located on a surface of the land conductor, a wall surface of the via hole, and the second surface. A plurality of voids are located in at least a portion of the underlying metal layer.

Dependencies are inferred from the claim text.