METHOD FOR FABRICATING ISOLATION LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to easily control the depth of a trench by determining an endpoint of a trench etch process, and to improve a refresh characteristic by rounding both ends of the trench. CONSTITUTION: After a multilayer pad is formed on a silicon substrate(100) and a test layer is deposited on the multilayer pad, a photoresist layer pattern is formed. After the test layer is etched by using the photoresist layer pattern as an etch mask to expose the upper portion of the multilayer pad, the photoresist layer pattern is eliminated. The multilayer pad is over-etched by using the test layer as an etch mask to form a slope in the silicon substrate so that a multilayer pad pattern is formed. A trench is formed in the silicon substrate through an etch process using the test layer as an etch mask. A cleaning process is performed to remove the polymer generated in forming the multilayer pad pattern. An oxide process is performed on the sidewall of the trench to form a sacrificial oxide layer(160). A gap-fill oxide layer is deposited to form an isolation layer(170).