To solve the problem of the conventional semiconductor devices that when a high-breakdown voltage semiconductor device is used over a long term, corrosions of its aluminum wirings and its increased leakage currents, etc., which are caused by the moisture contained in its mold resins are generated and shortens its life time.

In a semiconductor device, having a passivation film comprising silicon nitride films formed by a plasma CVD method, the silicon nitride films, comprise a first silicon nitride film 15 which has a comparably high refractive index and is positioned on the lower-layer side of the passivation film and a second silicon nitride film 16, which has a comparably low refractive index and is positioned on the upper-layer side of the passivation film.