Method of forming shallow trench isolation structure

摘要

A method of forming a shallow trench isolation (STI) structure is disclosed. Instead of using a conventional chemical mechanical polishing (CMP), a wet etching is used in the present invention while forming a shallow trench isolation structure. By using the high selectivity of the wet etching, the thickness of the silicon nitride (Si3N4) layer and the oxide layer in the shallow trench isolation structure can be decreased or controlled, and the micro-scratch caused by the chemical mechanical polishing can be avoided.