A Soft-X-Ray Imaging Microscope with a Multilayer-Coated Schwarzschild Objective: Imaging Tests

We constructed a soft-X-ray imaging microscope based on a multilayer-coated Schwarzschild objective. It provides an element-sensitive image in terms of the characteristic soft X-rays selectively reflected by the multilayer coating. The Schwarzschild objective was designed to have a 50× magnification and a numerical aperture of 0.25. The mirrors of the objective were coated with Mo/Si multilayers to reflect the Si L emission. The overall throughput of the objective was 14% at a peak wavelength of 13.3 nm. The 5-µm-wide stripe of lithographically patterned SiO 2 was observed under irradiation with an electron beam of 1 µA accelerated to 2.5 kV.