METHOD FOR FABRICATING ISOLATION LAYER

摘要

PURPOSE: A method for fabricating an isolation layer is provided to decrease an aspect ratio regarding a gap fill and to improve an overlap margin of a photolithography process used in a shallow trench isolation(STI) process, by forming an isolating oxide layer of which the area is decreased as compared with a conventional technology and by forming a single silicon layer on the entire surface. CONSTITUTION: A pad insulation layer in which a pad oxide layer and a pad nitride layer for exposing an isolation region are stacked, is formed on a substrate(31). The substrate is etched to form a trench by using the pad insulation layer as a mask. The isolating oxide layer(35) is formed in the trench including the pad insulation layer. The pad nitride is removed to make the isolating oxide layer protrude by the height of the pad nitride layer. The pad oxide layer is over-etched by a wet etch method to eliminate the pad oxide layer. The side surface of the protruding portion of the isolating oxide layer is selectively etched.