PURPOSE: To protect semiconductor devices from mechanical stress externally imposed to prevent their damages with respect to the substrate by forming width dimension of each electrode fabricated on the back side of substrate equal to or a little wider than the semiconductor device.

CONSTITUTION: A GND electrode 15 fabricated on the back side of a substrate 11 has a basic feature: Width dimension of the GND electrode 15 is made equal to or a bit larger than die pad 12, fabricated on the backside of substrate 11, in its turn to width dimension of semiconductor device 16 connected to mount on this die pad 12 over its total length. As a result, gap A between each electrode 14 mounted on the backside of substrate 11 and the GND electrode 15 turns to be located outside of the width range of the semiconductor device 16 on the front side facing this, resulting in effective elimination of scattering in intensity at least in the direction of width for the whole portion of this semiconductor device 16.