TRENCH ISOLATION METHOD

摘要

PURPOSE: A method for isolating a trench is provided to prevent a dent generated at edge portions of the trench isolation and improve a uniformity by removing a pad nitride using a dry etching instead of CMP(chemical mechanical polishing). CONSTITUTION: The method comprises the steps of forming a trench mask layer (110) having a first nitride film (104) on a semiconductor substrate (100); forming a trench (112) by etching the semiconductor substrate (100) using the trench mask (110); forming a thermal oxide (114) at both sidewalls and bottom of the trench (112); forming a thin nitride film (116) on the trench mask (110) and the thermal oxide (114); forming a trench isolation layer (118) on the second nitride film (116) to fill the trench; fattening the trench isolation layer (118) to expose the upper surface of the first nitride film (104); and dry etching the first nitride film (104) and the trench isolation layer (118) to entirely remove the first nitride film (104).