ISOLATION METHOD USING A TRENCH IN A SEMICONDUCTOR DEVICE

摘要

PURPOSE: An isolation method using a trench in a semiconductor device is provided to improve reliability of a gate oxidation layer, by preventing a thickness of the gate oxidation layer from becoming thin on the edge of an isolation part. CONSTITUTION: A wafer is prepared. A pad oxidation layer(3) and a nitride layer(5) are formed on the wafer, and an isolation part(11) is formed and planarized. The wafer is thermally processed, and an oxidation layer on the edge of the isolation part is grown. The nitride layer and pad oxidation layer are eliminated. A gate oxidation layer is grown on the surface of the wafer.