SEMICONDUCTOR DEVICE

PURPOSE:To improve reliability for being strong enough against an electrostatic noise to be given from outside by providing opening parts electrically connecting a metal wiring layer to diffusion layers together with the metal wiring layer on the diffusion layers while making a distance from the opening hole parts to the ends of the diffusion layers much longer than the similar distance in the other region. CONSTITUTION:When a noise in a forward direction of the connection of a diffusion layer 2 and a substrate is given from outside to an input terminal 1, the impurities implanted inside the substrate drifts inside the substrate as a diffusion current for being absorbed by the diffusion layer 4 and 6 of constant potential lying most closely. At this time, the impurities are being absorbed by an aluminium wiring from the nearest opening parts 7 and 9 from the input terminal 1 inside the diffusion layers 4 and 6 usually absorbing the impurities. Accordingly, a big current temporally concentrates from the diffusion layer ends at the opening hole parts so that the distance l1 between them is made larger enough than the usual distance l2. Thereby, a clamp action of the diffu sion layer resistance prevents connection breakdown due to an impurity current.