EUV and soft x-ray multilayer optics

Abstract

The demand to enhance the optical resolution, to structure and observe ever smaller details, has pushed the way towards the EUV and soft X-rays. Induced mainly by the production of more powerful electronic circuits with the aid of projection lithography, optics developments in recent years can be characterized by the use of electromagnetic radiation with smaller wavelength. The good prospects of the EUV and soft X-rays for next generation lithography systems (λ = 13.5 nm), microscopy in the "water window" (λ = 2.3 - 4.4 nm), astronomy (λ = 5 - 31 nm), spectroscopy, plasma diagnostics and EUV/soft X-ray laser research have led to considerable progress in the development of different mulilayer optics. Since optical systems in the EUV/soft X-ray spectral region consist of several mirror elements a maximum reflectivity of each multilayer is essential for a high throughput. This paper covers recent results of the enhanced spectral behavior of Mo/Si, Cr/Sc and Sc/Si multilayer optics.