Patent ID: 7674989
Filing Date: 2010-03-09
Classification: H05K,Y10T

Abstract:
1. A wiring board for mounting a semiconductor element or an electronic component, said wiring board comprising: a plurality of wiring layers; one or a plurality of insulating layers provided between said wiring layers; and vias provided to said insulating layer and electrically connect the upper and lower wiring layers of said insulating layer which is provided with said vias; wherein at least one of said vias is designed so that the cross-sectional shape of the via in the plane parallel to said wiring layers is obtained by the partial overlapping of a plurality of similar shapes and the at least one of said vias does not overlie any vias provided to the one or the plurality of insulating layers, in the plane parallel to said wiring layers, the similar shapes are one of convex polygons, convex polygons with at least one curved vertex, or rounded shapes with no straight edges, the partial overlapping does not include a center point of any of the plurality of similar shapes, and the cross-sectional shape of said at least one of said vias is narrowest across said overlapping portion.