OPTIMIZATION TECHNIQUES APPLIED TO INITIAL DESIGNS OF ULTRAVIOLET LITHOGRAPHIC OBJECTIVES

The optimization of lithographic objectives is a quite challenging task due to many conflicting constraints, limitations and numerous variables. We describe the optimization techniques of starting designs for ultraviolet objectives which were previously generated by the global search algorithm. The powerful tools for the global optimization as Automatic Element Insert feature and Saddle points construction were applied to starting points, examining the applicability limited by design considerations. The ray tracing failures and critical lenses in starting designs caused by automatic decisions of the global search algorithm are fixed and replaced by Saddle point construction. The results of this work and presented techniques of the global optimization are valid and relevant for any on-axis complex optical system.