The semiconductor device consists of a substrate (201) and an intermediate layer insulating film (204) or a passivation insulating film each formed on the substrate. They each contain silicon, oxygen, carbon and hydrogen the carbon content being no less than the silicon content. The insulation film can have a dielectric constant of 1.8 to 3.2 and the atomic ratio of carbon to silicon in the insulation film can be 1 to 3. A surface layer of the insulation film can have a higher viscosity than the remainder of the film.
