METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming an isolation layer of a semiconductor device is provided to improve gap-filling capability of the isolation layer by forming a trench structure having double slope using a polymer spacer. CONSTITUTION: A pad oxide layer(200) and a nitride layer(300) are formed on a silicon substrate(100) defined by an active region(101) and a field region(102). The silicon substrate(100) of the field region(102) is exposed by selectively etching the nitride layer(300) and the pad oxide layer(200) using a photoresist pattern as a mask. A polymer spacer is formed at both sidewalls of the resultant patterns. A trench is formed by firstly etching the exposed silicon substrate(100) using the polymer spacer as an etch stopper. After removing the polymer spacer and the photoresist pattern, a double-sloped trench structure(600) is formed by secondly etching the trench using the nitride layer(300) as an etch stopper.