Minimization of Flare in EUVL by Simultaneous Wire Segment Perturbation and Dummification

Abstract

Extreme Ultraviolet Lithography (EUVL) suffers from pattern distortion defects caused by flare, which is irregular reflection from the surface of the mask used. While techniques based on (a) dummification and (b) perturbation of wire segments have reduced flare notably, each has its own merits and demerits. Unlike earlier works where each method for flare reduction is applied independently, in this paper we extensively study the effects on flare and the amount of dummy fills required by simultaneous dummification and wire segment perturbation using an Integer Linear Programming (ILP) based formulation in a multilevel framework at the post-routing stage. Experimental results show an average reduction of maximum flare level by 29% compared to that in the initial routed layout. In addition to that, an average reduction of maximum flare by 19% is observed compared to the method of wire perturbation alone. Moreover, in our method 35% reduction in dummy requirement on average is achieved compared to the application of dummification technique alone for the reduction of flare.