PROTECTIVE FILM FOR SEMICONDUCTOR ELEMENT AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To obtain a protective film in which the damage of an element due to the permeation of moisture from the outside is reduced to a minimum, by a method wherein a silicon oxide film is vapor-deposited, a silicon nitride film is formed at the upper part of the silicon oxide film, and a chromium oxide film is then vapor-deposited. SOLUTION: A semiconductor element is formed at the upper part of a semiconductor substrate, and a silicon oxide film 2 which is to be used as the lower-part layer of a protective film is vapor-deposited in a state that a metal interconnection to be used as a conductive interconnection is formed on the uppermost-part face. In addition, a silicon nitride film 3 is vapor-deposited at the upper part of the silicon oxide film 2. Then, a chromium oxide film 4 which is excellent in a corrosion-resistant characteristic is vapor-deposited by using a physical vapor deposition method. Thereby, the compressive stress of the silicon nitride film 3 is relaxed, it is possible to prevent a crack from being generated, and the damage of the element due to the permeation of moisture from the outside can be reduced to a minimum.