Patent ID: 11917751
Assignee: TOPPAN HOLDINGS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A multilayer wiring board, comprising:
a plurality of metal wiring layers alternately laminated with an insulating layer interposed therebetween are electrically connected to each other via a via hole plated layer formed on a surface of a via hole, wherein
a dissimilar metallic layer, made from material different from that of the metal wiring layers, is interposed between each of the metal wiring layers on a bottom surface of the via hole and the via hole plated layer,
a concave portion is formed in each of the metal wiring layers on the bottom surface of the via hole at a position in contact with the dissimilar metallic layer, and
the dissimilar metallic layer is arranged in a concave shape on a surface of the concave portion which is formed in each of the metal wiring layers on the bottom surface of the via hole, wherein the concave portion has a multilevel structure in which a cross-sectional area of an opening of the concave portion increases stepwisely from the bottom surface of the concave portion toward the via hole, and wherein the multilevel structure comprises (a) a first level comprising the bottom surface, the first level has a first diameter of the opening and (a) a second level having a second diameter of the opening, wherein the first diameter is between 50% and 100% of the second diameter.