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 a production yield and an electric characteristic in a semiconductor element isolation process by compensating an etching damage generated when forming an isolation layer in a trench. CONSTITUTION: A pad oxide layer(102) and a nitride layer(104) are deposited on a semiconductor substrate(100). The substrate is patterned from the nitride layer by using a photoresist layer for an isolation mask, thereby forming a trench(106) in the substrate. The photoresist layer is removed, a first thin oxide layer(108) is formed in the trench at a temperature of beyond 1000deg.C at an atmospheric pressure. A second thin oxide layer(110) is formed at a temperature of 700-850deg.C at a low pressure of below 1Torr. A third oxide layer(112) for sufficiently filling the inside of the trench is formed at a temperature of 550-650deg.C at a high pressure of 1Torr over. The third oxide layer is polished until the nitride layer is exposed by an evenness process, thereby forming an isolation layer(ISO) made of first to third oxide layers buried in the trench. The nitride layer and the pad oxide layer are removed. Thereby, the method for forming an isolation layer of a semiconductor device compensates an etching damage generated when forming the isolation layer in the trench, and thus improves a production yield and an electric characteristic in a semiconductor element isolation process.