| 摘要 |
PROBLEM TO BE SOLVED: To flatten the surface of filling material by etch back when the inside of a trench with high aspect ratio is filled by filling material. SOLUTION: A first filling material 6 is arranged on a semiconductor substrate 5 including inside of a trench 5, a second filling material 7 is arranged on the first material 6, and then, the second filling material 7 and the first filling material 6 are etched back. In this case, material with high flowability is used for the first filling material 6 and material with high etch back resistance for the second pad material. Thus, the method prevents the first filling material 6 at the central part of the trench 5 from being etched with precedence and can more flatten the surface of the filling material by etch back.
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