| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming an element separation structure which has no possibility of bringing about an undesired mechanical stress caused by the unbalance of the front and rear surfaces of a semiconductor substrate due to the presence or absence of a trench in the semiconductor substrate by moisture absorbing to expand the oxide film embedded in the trench. SOLUTION: The method for forming this element separation structure includes a trench forming step of forming the trench 5 in the silicon substrate 1; an oxide film dividing and growing step of dividing and growing first, second and third NSG films 102, 102 and 103 so as to embed by dividing into three times in the trench 5; a heat treating step of heating at a high temperature the NSG films 101, 102 and 103 at each dividing and growing; and a surface flattening step of flattening the surface of the silicon substrate 1. COPYRIGHT: (C)2005,JPO&NCIPI
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