METHOD FOR FABRICATING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a semiconductor device is provided to improve an overlap margin between a polysilicon layer pattern and a field oxide layer, by forming a sufficiently high nitride layer pattern so that a spacer is not lost. CONSTITUTION: An isolation region is formed in a predetermined region of a semiconductor substrate(21). A polysilicon layer is formed on the entire surface of the semiconductor substrate. The first nitride layer having a thickness from 1000 to 2000 angstrom is formed on the entire surface. The first nitride layer is selectively removed to be in a predetermined region of the polysilicon layer. The second nitride layer is deposited on the semiconductor substrate. The second nitride layer is selectively removed to be on both side surface of the selectively removed first nitride layer so that a nitride layer sidewall is formed. The polysilicon layer is selectively eliminated to expose the isolation region by using the selectively removed first nitride layer and the nitride layer sidewall as a mask. The selectively removed first nitride layer and the nitride layer sidewall are eliminated by using a phosphoric acid solution.