| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device for preventing the thinning phenomenon of a gate oxide film formed in a peripheral region. SOLUTION: A pad oxide film 21 and a pad nitride film 22 are successively formed on a semiconductor substrate; and the pad nitride film 22, the pad oxide film 21, and a semiconductor substrate 20 in a field region defined in a cell region are etched so that a first trench 23 can be formed. A first photo-resist is formed for exposing the field region defined in the peripheral region; and the pad nitride film 22, the pad oxide film 21, and the semiconductor substrate 20 are etched by using the first photo-resist as a mask so that a second trench 25 can be formed. The top corner of the semiconductor 20 in the peripheral region is rounded, the first photo-resist is removed, and an element isolation film is formed in the first trenches 23 and 25. The pad nitride film 22 and the pad oxide film 21 are removed so that the semiconductor substrate 20 in the active region can be exposed, and a gate oxide film 26 is formed. COPYRIGHT: (C)2007,JPO&INPIT
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