The invention is directed to improvement of reliability of a semiconductor device having penetrating electrodes by preventing a protection film and an insulation film peeling. A peeling prevention layer for preventing an insulation film and a protection layer peeling is formed in corner portions of the semiconductor device. The peeling prevention layer can increase its peeling prevention effect more when formed in a vacant space of the semiconductor device other than the corner portions, for example, between ball-shaped conductive terminals. In a cross section of the semiconductor device, the peeling prevention layer is formed on the insulation film on the back surface of the semiconductor substrate, and the protection layer formed of a solder resist or the like is formed covering the insulation film and the peeling prevention layer. The peeling prevention layer has a lamination structure of a barrier seed layer and a copper layer formed thereon when formed by an electrolytic plating method.