Lithography process optimization simulator for an illumination system

Abstract

Resolution enhancement technology and optical proximity correction are widely used in a lithography process in order to overcome the resolution limit for the best lithography performance. Among the many lithographic parameters, numerical aperture, illumination type, and partial coherence most strongly influence the optimum result. Since these three elements give different results in different combinations, it is important to find the best illumination condition. However, illumination combination cannot improve all lithographic results simultaneously. For example, the resolution-improving combination that is best only for a dense pattern can amplify the proximity effect. In this paper, the tendency of photo results dependent on the change of illumination is shown in one simple plot, so that the optimized optical system conditions can be easily obtained for the best results of critical dimension uniformity. Our work will give quick, good process conditions that can be easily applied in a device manufacturing environment by a lithography engineer. This paper discusses the use of simulation to determine the optimum lithographic parameters for any arbitrary patterns.