Extreme ultraviolet lithography objective design based on grouping and graphical user interface

Extreme ultraviolet lithography (EUVL) objective with high NA and large exposure field is the core component of lithography equipments for high volume manufacture (HVM) aiming at 22 nm node and beyond. The visual generation of the initial construction of EUVL objectives is presented based on the analysis of the valid objectives and grouping strategy. With alternation of step by step increasing NA and optimizations, λ/50 root mean square (RMS) composite wavefront error has been achieved in the 2 mm wide arc full field with a chord length of 26 mm. By the aids of Q-type polynomials, the maximum asphericity and diameter of mirrors have been optimized less than 45 μm and 400 mm, respectively. And finally the full-field composite wavefront error is better than 0.027λ RMS and the distortion is less than 1.5 nm. © 2015, Chinese Laser Prees. All right reserved.