METHOD FOR FABRICATING ISOLATION LAYER OF SEMICONDUCTOR DEVICE TO PREVENT HUMP AND ELECTRIC FILED CONCENTRATION PHENOMENON

摘要

PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to prevent a hump and an electric filed concentration phenomenon by improving a rounding characteristic of the upper corner of a trench. CONSTITUTION: A pad oxide layer and a pad nitride layer are sequentially formed on a silicon substrate(100) and are selectively etched to define an isolation region on the substrate. A predetermined depth of the substrate in the isolation region is etched to form a trench. By using the pad nitride layer as an etch mask, a part of the edge of the pad oxide layer is etched to expose a part of the substrate by the first pull-back process. The first plasma isotropic etch process is performed on the exposed substrate. A part of the edge of the pad oxide layer is etched to expose a part of the substrate by the second pull-back etch process. The second plasma isotropic etch process is performed on the exposed substrate.