METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a semiconductor device is provided to improve the reliance and features of the semiconductor device by forming a lower portion of a trench in a round type. CONSTITUTION: A pad insulating layer(33) and a nitride layer(35) stacked on the pad insulating layer(33) are formed on a semiconductor substrate(31). A photoresist pattern(37) is formed on an upper portion of the nitride layer(35) so as to expose an isolation region. The stacked structure is etched by using the photoresist pattern(37). The semiconductor substrate(31) is anisotropic etched by using the photoresist pattern(37) to form a trench(39). Then, the semiconductor substrate(31) is isotropic etched by using the photoresist pattern(37) with a fluorine based gas to form a lower portion of the trench(39) in a round type. Finally, the photoresist layer(37) is removed.