METHOD FOR FORMING TRENCH ISOLATION FILM OF SEMICONDUCTOR DEVICE

PURPOSE: A method for forming a trench isolation film of a semiconductor device is provided which can suppress stress induced on a substrate during a post thermal oxidation process after a shallow trench isolation process. CONSTITUTION: A method for forming a trench isolation film suppresses stress induced on a silicon substrate(101) during a thermal oxidation process. The method suppresses an oxidation gas to penetrate into the semiconductor substrate during the post thermal oxidation process, by forming a nitride layer(200) at an interface between a trench side wall oxide and the semiconductor substrate by performing a nitrogen ion implantation, after forming a trench(104) and the trench side wall oxide. Therefore, the method can prevent the defect of semiconductor lattice.