Patent ID: 6821689
Filing Date: 2004-11-23
Classification: G03F,H01L,Y10T

Abstract:
A method for using an exposure through a second mask to assist an exposure through a phase shifting mask in printing a tight space adjacent to a large feature, comprising:exposing a photoresist layer on the surface of a semiconductor wafer through the phase-shifting mask, wherein the phase-shifting mask includes phase shifters that define a space between a first feature and a second feature; wherein the first feature is sufficiently large that the effectiveness of phase shifting is degraded in defining the space; wherein the degradation in phase shifting and the tightness of the space cause the space not to print reliably when exposed through the phase shifting mask alone; and exposing the photoresist layer through the second mask, wherein the exposure through the second mask assists in exposing the space between the first feature and the second feature so that the space prints reliably.