PURPOSE: To eliminate cross talk between adjacent wiring and prevent noise by permitting at least one layer of metal wiring to have a structure that covers almost whole plane of a substrate except an opening that introduces the top and bottom layer connecting parts and connecting the layer with power source or ground potential.

CONSTITUTION: First layers 2, 3 and 4 are arranged on a substrate 1. Then, second layer 5 is arranged on the layers 2, 3 and 4 and a third layer 7 is arranged at the top. The second layer 5 connected with a diffused layer 9 covers the whole plane of the substrate 1 except an opening 10 for introducing the connection of the first layer 3, which is connected with the diffused layer 8, with the third layer 7 and is connected with ground potential. Therefore, the diffused layer 9 is permitted to have ground potential. Thus, the first layer 2 and the third layer 7 are shielded by the second layer 5 and cross talk between a top layer wiring signal and a bottom layer wiring signal is eliminated. As a result, noise of the adjacent wiring signals is prevented.