A semiconductor device of the invention includes a semiconductor element (1), an interposer (5) having electrodes (2) arranged on a top face thereof in four directions and external electrodes (4) arranged on a bottom face thereof with the semiconductor element (1) mounted on the top face thereof, an adhesive material (6) fixing the semiconductor element (1) to the interposer (5), metal nanowires (7) electrically connecting between electrodes of the semiconductor element (1) and the electrodes (2) of the interposer (5), an insulating material (8) sealing a region containing the semiconductor element (1) and the metal nanowires (7), and metal balls (9) mounted on the external electrodes (4). Patterns (10) are designed on corners of a region surrounded by electrodes (2) arranged on the interposer (5) in four directions.