PURPOSE: To improve reliability of a semiconductor element by providing a specific SiN film on the surface of the semiconductor element.

CONSTITUTION: A first SiN film 7 contains a large amount of hydrogen and shows a small refractive index and therefore an entering path for water contents from external side of an element can be elongated by making thick the film. A second SiN film 8 contains a small amount of hydrogen and shows a large refractive index and therefore water content is blocked and cannot pass therethrough. The moisture-proof characteristic can be improded as a whole. Moreover, since the first SiN film 7 is formed thick, it has a tensile stress. Meanwhile, the second SiN film 8 contains a small amount of hydrogen and therefore it shows a compression stress. Accordingly, the stresses of the first SiN film 7 and the second SiN film 8 are cancelled with each other, an internal stress can be eased as a whole. Thereby, characteristics of the SiN films 7, 8 may be utilized effectively, enhancing reliability of the semiconductor element.