METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming an isolation layer is to prevent the thinning of a gate oxide layer generated in an opening part of a trench when forming the isolation layer using an STI(Shallow Trench Isolation) method. CONSTITUTION: A pad oxide layer is formed on a semiconductor substrate(300). A silicon nitride layer is formed on the pad oxide layer. A silicon nitride layer pattern is formed by patterning the silicon nitride layer and the pad oxide layer. A spacer insulating layer is formed on the entire surface of the semiconductor substrate including the silicon nitride layer pattern. A spacer is formed on both sidewalls of the silicon nitride layer pattern by patterning the spacer insulating layer. A trench is formed in the semiconductor substrate by etching the substrate, using the spacer as an etch mask. A sidewall oxide layer(312) is grown on the sidewall of the trench. A liner(314) is formed on the entire surface of the semiconductor substrate including the trench and the silicon nitride layer pattern. An oxide layer(316) is formed on the entire surface of the semiconductor substrate to fill in the trench. After removing the silicon nitride layer pattern and the pad oxide layer, a gate oxide layer(318) is formed on the exposed semiconductor substrate.