To provide a semiconductor device which can be prevented from deteriorating in characteristics in a radiation environment by a method wherein a surface potential level that causes deterioration in characteristics is restrained from being produced.

In a semiconductor device where a first and a second interlayer insulating film, 5 and 7, are formed on an Si substrate 1 through the intermediary of a first and a second interlayer insulating film of SiO2, the interlayer insulating films other than those just under a first and a second wiring, 5 and 7, are removed by etching, and an insulating film 10 is formed only under the wirings. By this setup, an SiO2 insulating film forming region which serves as a source to generate hydrogen that produces a surface potential level is reduced to an irreducible minimum, atomic hydrogen is less generated even in a radiation environment, and an interface state density is restrained from being generated, so that a semiconductor device of this constitution can be prevented from deteriorating in characteristics.