METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

A method for forming an isolation layer in a semiconductor device is provided to form voids at a lower of a trench by modifying a structure of a trench. A hard mask layer for exposing an isolation region is formed on a silicon substrate(21) including an active region and the isolation region. A first trench(23) is formed by etching the exposed part of the isolation region. A first liner oxide layer and a liner nitride layer(28) are formed on the silicon substrate. The liner nitride layer and first liner oxide layer are removed from an upper part of the hard mask layer and a bottom surface of the first trench. A second trench(26) is formed by etching the silicon substrate under the first trench. The remaining parts of the liner nitride layer and the first liner oxide layer are removed. The first and second trenches are buried by an insulating layer.