| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device and its manufacturing method which can prevent deterioration of element characteristic and reliability which are to be caused by phenomena that a trench filling insulating material which is protruded in a protruding shape is largely hollowed from its side surface, and a trench top corner part of a semiconductor substrate is exposed, in a semiconductor device of a trench insulating type and its manufacturing method. SOLUTION: A trench is formed in an element isolating region of a semiconductor substrate 10, and the inner wall of the trench is covered with silicon oxide films 20 and 24. The inside of the trench is filled with a CVD oxide film 26 as trench filling insulating material. The upper part of the CVD oxide film 26 is protruded in a protruding shape from the surface of the semiconductor substrate 10 of an element forming region, and the sidewall of the protruded upper part is covered with a silicon oxide film 24 as a barrier insulating film whose etching resistance is higher than that of the CVD oxide film 26.
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