| 摘要 |
PROBLEM TO BE SOLVED: To prevent cracking due to warpage even when an oxide film material is formed by isolating a trench element in an SOI wafer. SOLUTION: In case when a polycrystalline silicon film 13 to be used as a mask material is formed when a trench 5 is formed in the SOI wafer 1, a polycrystalline silicon film 13a remaining on its backside is removed in the following step. Thus, a recessed warpage on the upper surface of the SOI wafer 1 due to the polycrystalline silicon films 13 and 13a having compressibility is prevented. In addition, a cracking G is prevented from being caused in the trench 5 on a suction stage 21 of the device because of the recessed warpage. COPYRIGHT: (C)2004,JPO
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