A polygonal semiconductor device includes a substrate and a wiring layer. The substrate includes semiconductor circuit elements. The wiring layer includes a dielectric sealing layer, a plurality of first electrodes, and a plurality of second electrodes. The first and second electrodes both extend through the dielectric sealing layer in its thickness direction. The first electrodes are electrically connected to the semiconductor circuit elements. Each of the corners of the polygonal device is formed, throughout the thickness of the wiring layer, by one of the second electrodes. The corners of the device are thereby reinforced, as the electrode material is tougher than the dielectric sealing material.