| 摘要 |
PROBLEM TO BE SOLVED: To protect an element isolation film against damage caused by misalignment of a mask by a method wherein an undercut region is provided below the side wall of an anti-oxidizing film pattern by isotropic etching, an edge is located in the undercut region, and an element isolating film is formed. SOLUTION: A pad oxide film 22 and a nitride film 23 are evaporated on a silicon substrate 21 so as to define a region where an element isolation film is formed. The silicon substrate 21 is continuously and isotropically etched as deep as 500Åthrough an etching apparatus for the formation of a nitride film spacer 25a. An undercut region C is provided to a part of the silicon substrate 21 joined to the edge of the nitride film spacer 25a obtained by isotropic etching. A field oxide film 26 is formed through an oxidation process. At this point, the edge of the field oxide film 26 is positioned in the undercut region and restrained from being exposed on the surface of the silicon substrate.
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