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 be capable of restraining divot in STI(Shallow Trench Isolation) processing. CONSTITUTION: A pad oxide pattern(32) and a pad nitride pattern(33) are formed on a silicon substrate(31). A trench(34) is formed by etching the exposed substrate. By wet-cleaning of the pad oxide pattern, under-cut portions are formed at the top edge portions of the trench. By sequentially performing chemical dry-etching and sacrificial oxidation processing, a bird's beak(37) and a linear oxide layer(35) are simultaneously formed. An isolation layer is then formed by filling an oxide layer into the trench and polishing the oxide layer to expose the pad nitride pattern.