METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE USING TRENCH ISOLATION PROCESS

摘要

PURPOSE: A method for manufacturing semiconductor device using trench isolation process is provided to prevent from generating a thinning of a gate oxide layer on an active region, the thinning being caused by an NH3 heat treatment for restricting a stress induced by post thermal oxidizing process, thus to improve an electrical characteristic of the device. CONSTITUTION: A manufacturing method comprises the steps of: forming a trench on an isolation region on a semiconductor substrate(20); forming a thermal oxidizing layer to fill the inner face of the trench; heat-treating the former object in NH3 atmosphere to form a nitride layer(24) on an interface between the semiconductor substrate and the thermal oxidizing layer; forming a field oxide layer(25) buried in the trench; forming a gate sacrificial oxide layer on an active region of the semiconductor substrate in such a manner that the nitride layer being oxidized in sufficient depth; removing the nitride layer by removing the sacrificial oxide layer; and forming a gate oxide layer(27) on the active region of the semiconductor substrate.