| 摘要 |
PROBLEM TO BE SOLVED: To accurately embed a silicon oxide film inside a device isolation trench. SOLUTION: A side wall film 4 comprising a silicon nitride film 3 and an silicon oxide film is formed on a device forming a region on a semiconductor substrate 1 via a pad oxide film 2, a trench 5 is formed in the device forming region by etching the semiconductor substrate 1 with the films as a mask, and a thin oxide silicon film 7 is deposited by an optical CVD method after a thin oxide silicon film 6 is formed on the inner wall of the trench by thermal oxidation. Then, after the silicon oxide film 7 is polished until the silicon nitride film 3 is exposed, the silicon nitride film 3 and pad oxide film 2 are removed.
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