A semiconductor device includes a semiconductor substrate having a first surface and a second surface opposing each other, and a side surface between the first and second surfaces, and including a device region on the first surface a wiring structure on the surface of the semiconductor substrate, and having a dielectric layer and a metal wiring in the dielectric layer and electrically connected to the device region, and an insulating material layer on a side surface of the wiring structure and having a side surface connected to the side surface of the semiconductor substrate. The side surface of the insulating material layer has a first wave-shaped pattern in which concave-convex portions are repeated in a direction of the wiring structure that is perpendicular to the semiconductor substrate, and the side surface of the semiconductor substrate has a second wave-shaped pattern in which concave-convex portions are repeated in the direction.