Patent ID: 8450621

Claim:
A wiring board, having at least one hole, the wiring board comprising: an insulating layer has a first surface and a second surface opposite to the first surface, wherein the at least one hole extends from the first surface to the second surface; a first wiring layer embedded in the insulating layer at the first surface, wherein the first wiring layer has a first top surface exposed by the insulating layer and a first bottom surface which is opposite to the first top surface and is in contact with the insulating layer; a second wiring layer embedded in the insulating layer at the second surface, wherein the second wiring layer has a second top surface exposed by the insulating layer and a second bottom surface which is opposite to the second top surface and is in contact with the insulating layer; and at least a conductive pillar, disposed in the hole, and connected between the first wiring layer and the second wiring layer, wherein the conductive pillar has a pillar top surface exposed by the insulating layer at the first surface and a pillar bottom surface which is exposed by the insulating layer at the second surface and is opposite to the top surface, and the diameter of conductive pillar gradually shrinks from a first level of the first bottom surface of the first wiring layer towards the pillar top surface.