A dielectric layer is formed on a first metal layer, the dielectric layer is formed with many concave portions at the upper surface. A second metal layer is formed on the dielectric layer, the second metal layer is formed with a convex portion at a position corresponding to each of many concave portions. A capacitances is generated between the first and second metal layers. The capacitor element is composed of the first metal layer, the dielectric layer and the second metal layer. The first and second metal layers are used as power supply interconnection, the capacitor element is connected between a pair of power supply interconnections. Further, the first metal layer is connected to reference voltage, and the second metal layer is used as a pad electrode. By doing so, a capacitor element is connected between the pad electrode and the reference voltage.