METHOD OF FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE TO IMPROVE ROUNDING CHARACTERISTICS OF TOP CORNER AND BOTTOM OF TRENCH

摘要

PURPOSE: A method of forming an isolation layer of a semiconductor device is provided to round a top corner and a bottom of a trench by performing an isolation process using an STI(Shallow Trench Isolation) process. CONSTITUTION: A pad oxide layer and a silicon nitride layer are formed on a silicon substrate(21). An isolation region of the silicon substrate is exposed by patterning the silicon nitride layer and the pad oxide layer. A trench is formed by etching the exposed part of the silicon substrate. A part of the pad oxide layer corresponding to a top part of the trench is recessed by performing a wet-cleaning process for the trench. The top part of the trench is rounded by performing a dry-cleaning process using O2/CF4 plasma. The top part of the trench is rounded by performing a thermal oxidation process. A thermal oxide layer(26) is formed on a surface of the trench. A buried oxide layer is deposited thereon to bury the trench. A CMP process is performed to expose the pad nitride layer. The pad nitride layer is removed therefrom.