Patent ID: 9167692
Filing Date: 2015-10-20
Classification: H01L,H05K

Abstract:
1. A wiring board comprising: a first wiring layer; a first insulating layer covering the first wiring layer; a first via hole having an opening in an outer surface of the first insulating layer, an outer surface of the first wiring layer being exposed through the first via hole; a first via filling in the first via hole, the first via including an end surface exposed at the outer surface of the first insulating layer; a second wiring layer arranged on the outer surface of the first insulating layer and the end surface of the first via; a second insulating layer covering the second wiring layer; a second via hole having an opening in an outer surface of the second insulating layer, the outer surface of the second wiring layer being exposed through the second via hole; and a second via filling in the second via hole, the second via being smaller in diameter than the first via, the second via being arranged above the first via through the second wiring layer, wherein the entire second via hole overlaps the first via hole in plan view, the second insulating layer is thinner than the first insulating layer and the second wiring layer is thinner than the first wiring layer, the end surface of the first via includes a recessed part dented toward the first wiring layer, with the second wiring layer filling the recessed part, and the second wiring layer that is located above the end surface of the first via includes a top surface having greater flatness than that of the end surface of the first via.