A semiconductor device includes a semiconductor substrate. The semiconductor substrate has a first main surface and a second main surface opposite to the first main surface, and includes a first conductive layer formed on the second main surface. A through hole penetrates through the semiconductor substrate from the first main surface to the second main surface, so that the first conductive layer formed on the second main surface is exposed at a bottom portion of the through hole. A seed layer is formed on a side surface of the through hole from the bottom portion of the through hole to the first main surface; a second conductive layer is formed on the seed layer; and a third conductive layer is selectively formed on the second conductive layer.