| 摘要 |
PROBLEM TO BE SOLVED: To increase process margin, while reducing manufacturing cost in the formation of a trench capacitor which is increased in a capacitor area, by forming a silicon film having an uneven surface on an inner wall in the lower part of the trench. SOLUTION: A collar oxide film 9 is formed on the surface of a side wall in an upper part of the trench 5. Then, a siliocn film (HSG film) 10, having an uneven surface, is formed non-selectively over the whole surface of the inner wall of the trench 5, including the collar oxide film 9. Next, the HSG film 10 in an upper part of the sidewall of the trench 5 is removed to selectively leave the HSG film 10, in the lower part of the inner wall of the trench 5.
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