METHOD FOR MANUFACTURING A SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to round a lower portion of a trench, by performing an etching process where lots of polymer is generated, and by soft-etching the lower portion of the trench using the polymer as an etch blocking layer. CONSTITUTION: A stacked structure of a pad insulating layer(22) and a nitride layer(23) is formed on a semiconductor substrate(21). A photoresist layer pattern exposing a portion reserved for an isolation region is formed on the nitride layer. The stacked structure is etched by using the photoresist layer pattern as an etching mask while upper polymer is formed on the etched surface of the stacked structure. The semiconductor substrate is etched using the photoresist layer pattern and upper polymer as an etching mask to form a trench while lower polymer is evaporated on the etched surface of the trench. A lower portion of the trench is soft-etched by using the photoresist layer pattern and lower polymer as an etching mask to make the lower portion of the trench round.