Design and fabrication of robust broadband extreme ultraviolet multilayers

TL;DR

This paper presents an improved multiobjective genetic algorithm for designing broadband EUV multilayers that are less sensitive to layer thickness variations, with experimental validation of robust Mo/Si multilayer mirrors.

Contribution

The study introduces a robust design method using an enhanced genetic algorithm to create multilayers with broad angular bandpass and reduced sensitivity to fabrication errors.

Findings

Robust multilayers exhibit lower sensitivity to thickness fluctuations.

Experimental Mo/Si multilayers confirm the effectiveness of the design.

The robust design improves the practical performance of EUV multilayer mirrors.

Abstract

The random layer thickness variations can induce a great deformation of the experimental reflection of broadband extreme ultraviolet multilayer. In order to reduce this influence of random layer thickness fluctuations, the multiobjective genetic algorithm has been improved and used in the robust design of multilayer with a broad angular bandpass. The robust multilayer with a lower sensitivity to random thickness errors have been obtained and the corresponding multilayer mirrors were fabricated. The experimental results of robust Mo/Si multilayer with a wide angular band were presented and analyzed, and the advantage of robust multilayer design was demonstrated.