EXPOSURE METHOD FOR IMPROVING DEPTH OF FOCUS IN SMALL CONTACT PATTERN

摘要

PURPOSE: An exposure method for improving a depth of focus in a small contact pattern is provided to control a side lobe phenomenon of a phase shift mask by using multiple focus exposure method, and to solve a contrast problem by using an attenuated phase shift mask. CONSTITUTION: A photoresist layer is formed on a semiconductor substrate. Light having at least one depth of focus is irradiated by using the attenuated phase shift mask so that a small contact pattern is formed on the photoresist layer. The small contact pattern is not greater than 200 nanometer.