METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

A method for forming an isolation layer in a semiconductor device is provided to avoid generation of voids in an interlayer dielectric and eliminate the necessity of imposing a burden on a trench etch process and a gap-fill process by preventing an isolation layer from being decreased in thickness and avoiding generation of a recessed part on a liner oxide layer at the edge of the isolation layer. A barrier oxide layer and a pad nitride layer are sequentially formed on a semiconductor substrate(110). The pad nitride layer and the barrier oxide layer are patterned to expose a part of the semiconductor substrate corresponding to an isolation region. The exposed part of the semiconductor substrate is etched to form a trench. A liner oxide layer(116) and a liner nitride layer are sequentially formed on the inner surface of the trench. After a gap-fill insulation layer is formed to fill the trench by an HDPCVD process, the gap-fill insulation layer is planarized to form an isolation layer(120a). The liner nitride layer and the pad nitride layer are eliminated. The front surface of the semiconductor substrate is covered with a nitride layer. A photoresist pattern is formed which exposes the nitride layer on an active region defined by the isolation layer. After impurity ions are implanted, the exposed nitride layer is selectively eliminated.