| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming trench separation which prevents a device characteristic from getting worse by suppressing the occurrence of crystal defect caused by stress due to the shape change of a LOCOS oxide film when growing the oxide film for insulation on the side wall of a trench separation groove. SOLUTION: A CVD silicon oxide film 5 which functions as an etching mask for forming the trench separation groove 7 at the silicon layer 1 of an SOI substrate is formed, and a side wall 6 consisting of a silicon nitride film is formed on the side wall of the LOCOS oxide film 2. Thus, when forming silicon oxide for insulation on the side wall of the trench separation groove 7, the invasion of oxygen from the side wall of the LOCOS oxide film 2 is prevented since the side wall of the LOCOS oxide film 2 is covered with the side wall 6 consisting of the silicon nitride film. Thus, the method suppresses the occurrence of the crystal defect caused by the stress due to the shape change of the LOCOS oxide film 2 to prevent the device characteristic from getting worse. COPYRIGHT: (C)2005,JPO&NCIPI
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