Patent ID: 8450183
Filing Date: 2013-05-28
Classification: H01L

Abstract:
1. A method of manufacturing a power semiconductor device, comprising the steps of: (a) forming a silicon nitride film on a semiconductor substrate; (b) after said step (a), forming a ring-shaped trench along a peripheral portion of said semiconductor substrate as a terminal structure of a cell region, and defining the inside of the ring as said cell region; (c) forming a first silicon oxide film on an inner surface of said trench; (d) after said step (c), forming a second silicon oxide film on an entire surface of said semiconductor substrate to bury said trench; (e) planarizing said second silicon oxide film by using said silicon nitride film as a stopper; and (f) removing said silicon nitride film, and then forming a third silicon oxide film in a region in which said silicon nitride film is removed, wherein said third silicon oxide film is formed by thermal oxidation.