METHOD FOR FABRICATING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a semiconductor device is provided to precisely control a CD(critical dimension) by using a buffer oxide layer in etching a substrate for forming a trench or a contact hole. CONSTITUTION: After a pad oxide layer(12) and a nitride layer(13) are sequentially deposited on a substrate(11), a trench formation portion is defined by using photoresist. A buffer layer is deposited. The buffer layer is etched to form a sidewall on the side surface of the photoresist. The nitride layer is etched by using the sidewall as a mask. The substrate is etched to form a trench. The photoresist is eliminated. The sidewall is etched. The trench is filled with a field oxide layer(18) and is polished. The nitride layer is removed. The CD in etching the trench or the contact hole is controlled to be 0.20 micrometer or less.