Fabrication of high-efficiency multilayer-coated binary blazed gratings in the EUV regime

Improving the efficiency of soft X-ray and extreme ultraviolet (EUV) gratings by way of multilayer reflection coatings has been under investigation for many years. Here we present the fabrication and characterization of binary blazed gratings designed to operate in the 14 nm wavelength region. These binary gratings are stepped approximations to the ideal sawtooth blazed-grating profile and are fabricated directly into a layer of photoresist. Normal-incidence reflection efficiencies as high as 25% into the first-diffracted order have been demonstrated.