Isolation method of semiconductor device using second pad oxide layer formed through chemical vapor deposition (CVD)

摘要

An isolation method in the fabrication process of a semiconductor device is provided. The method forms an oxide layer as a buffer layer for reducing stress through chemical vapor deposition (CVD). By the method, a first pad oxide layer and a silicon nitride layer are formed on a semiconductor substrate, and then an silicon nitride layer pattern is formed by patterning, and undercuts are formed in the first pad oxide layer pattern. Subsequently, a second pad oxide layer is formed on the entire surface of the semiconductor substrate through CVD, and then spacers are formed on the sidewalls of both the patterned first pad oxide layer and silicon nitride layer and a field oxide layer is formed through thermal oxidation. Alternatively, a silicon layer is deposited without the spacers to form the field oxide layer. The second pad oxide layer is a buffer layer for buffering stress during formation of the field oxide layer.