Patent ID: 8621926

Claim:
A wiring substrate comprising: a substrate which has a first surface and a second surface; a first insulating layer which is stacked on the first surface; a pad electrode which is stacked on the first insulating layer; a through electrode which passes through the substrate and the first insulating layer and is connected to the pad electrode; and a second insulating layer which is disposed between the substrate and the through electrode and between the first insulating layer and the through electrode, wherein a diameter of the through electrode in a connection section between the pad electrode and the through electrode is smaller than a diameter of the through electrode on the second surface side, the first insulating layer, the second insulating layer and the through electrode overlap with each other in a peripheral area of the connection section between the through electrode and the pad electrode, when seen from a plan view, and a thickness of the first insulating layer gradually decreases from a position located outboard of the connection section to a position at the connection section.