METHOD FOR ISOLATING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for isolating a semiconductor device is provided to get a trench with a good profile without defects caused by the post wet processing and the process of removing a mask. CONSTITUTION: The side inferiority of a trench in removing a trench etch mask and in wet processing process is prevented by depositing a polycrystalline silicon(150) only on a side and a bottom of the trench and filling trench by oxidizing the polycrystalline silicon. The method comprises the steps of: forming the trench etch mask for isolation on a semiconductor substrate(110); forming the trench by etching the semiconductor substrate using the etch mask; depositing the polycrystalline silicon only on the side wall and the bottom of the trench; and filling the trench with the oxidized polycrystalline silicon after oxidizing the polycrystalline silicon.