METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming an isolation layer is to improve the characteristic and reliability of a semiconductor device. CONSTITUTION: A pad oxide layer is formed on a semiconductor substrate(11) at the thickness of 30 to 300 angstroms by using a thermal oxidization process. A pad nitride layer is formed on the pad oxide layer at the thickness of 500 to 3000 angstroms. A trench is formed by etching the pad nitride layer, the pad oxide layer, and the semiconductor substrate through an etching process using an isolation mask. The first insulating layer is formed on the entire structure of the semiconductor substrate having the trench. The first insulating layer is formed into undoped polysilicon. The second insulating layer is formed to bury in the trench and planarize the entire surface of the semiconductor substrate. The first and second insulating layers are etched by a CMP(chemical mechanical polishing) method until the pad nitride layer is exposed.