METHOD FOR FORMING ISOLATION REGION OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming an isolation region of a semiconductor device is provided to prevent the bird's beak and reduce the line width of a field region by forming a trench and a device separation film in forming a spacer. CONSTITUTION: A pad oxide film(102) and a silicon nitride film(104) are formed on a semiconductor substrate(100). By patterning the pad oxide film(102) and the silicon nitride film(104) in succession, isolation patterns having a predetermined pitch are formed. The width of the pitch is from 0.2 micrometer to 0.6 micrometer. A spacer membrane is formed on the whole semiconductor substrate(100) including the isolation patterns. A spacer is formed on both sidewalls of the isolation patterns by etching, and a trench is formed between the isolation patterns. An oxide film is grown to fill up the trench, so that an isolation region is formed.