Patent ID: 8610287

Claim:
A wiring substrate, comprising: an insulating layer; a wiring layer buried in the insulating layer; and a connection pad connected to the wiring layer via a via conductor provided in the insulating layer, and in which a whole of a side surface of the connection pad except a connection surface is buried in an outer surface side of the insulating layer; wherein the connection pad includes a first metal layer arranged on the outer surface side, an intermediate metal layer arranged on a surface of an inner layer side of the first metal layer, and a second metal layer arranged on a surface of an inner layer side of the intermediate metal layer, and a hardness of the intermediate metal layer is higher than a hardness of the first metal layer and the second metal layer, and a peripheral part of the intermediate metal layer is formed as a protrusion portion protruding from outer edge parts of the first metal layer and the second metal layer to an outside, and the protrusion portion is provided along outer edges of the first and second metal layer, and the connection pad is arranged in a bottom surface of a concave portion of the insulating layer, and a diameter of the concave portion is the same as the diameter of the intermediate metal layer.