An IC chip for a high frequency region, particularly, a packaged substrate in which no malfunction or error occurs even if 3 GHz is exceeded. A conductive layer is formed at a thickness of 30 μm on a core substrate and a conductive circuit on an interlayer resin insulation layer is formed at a thickness of 15 μm. By thickening the conductive layer, the volume of the conductor itself can be increased thereby decreasing its resistance. Further, by using the conductive layer as a power source layer, the capacity of supply of power to an IC chip can be improved.