A semiconductor device includes a semiconductor substrate having a first surface, a through silicon via (TSV) that is formed so that at least a part thereof penetrates through the semiconductor substrate, and an insulation ring. The insulation ring is formed so as to penetrate through the semiconductor substrate and so as to surround the TSV. The insulation ring includes a tapered portion and a vertical portion. The tapered portion has a sectional area which is gradually decreased from the first surface toward a thickness direction of the semiconductor substrate. The vertical portion has a constant sectional area smaller than the tapered portion.