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

摘要

PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to prevent a hump and concentration of an electric field by improving a round characteristic of an upper corner of a trench. CONSTITUTION: A pad oxide layer(110) and the first pad nitride layer are formed on a silicon substrate(100). The first pad nitride layer is partially etched to expose the pad oxide layer by a photolithography process. The exposed pad oxide layer is oxidized to form a field oxide layer. The first pad nitride layer is removed. The field oxide layer is planarized by a CMP(chemical mechanical polishing) process. The second pad nitride layer(150) is formed on the pad oxide layer and the field oxide layer. A photoresist layer pattern for defining a trench region is formed on the second pad nitride layer. The second pad nitride layer is removed by using the photoresist layer pattern as a mask. The field oxide layer is eliminated by using the photoresist layer pattern as a mask. A part of the silicon substrate is etched to form a trench(170) by using the photoresist layer pattern as a mask.