A semiconductor device includes a substrate and a semiconductor chip. The semiconductor chip includes a semiconductor element on a first surface thereof. The semiconductor chip is provided on the substrate such that a second surface thereof, which is opposite to the first surface, faces an upper surface of the substrate. A metal layer is provided between the second surface of the semiconductor chip and the upper surface of the substrate. A metal material, in which the range of α rays is shorter than for single-crystal silicon, is used in the metal layer.