High-efficiency multilayer-coated ion-beam-etched blazed grating in the extreme-ultraviolet wavelength region

We describe a simple method to fabricate blazed gratings used in the extreme ultraviolet wavelength region. The method uses an argon and oxygen mixed-gas ion beam to directly etch the grating substrate through a rectangular profile photoresist grating mask. With this method the etched grating groove profile can be well controlled. An $\mathrm{Mo}∕\mathrm{Si}$ multilayer-coated specimen with a blaze angle of $1.9°$ was fabricated and measured. At an incident angle of $10°$ and a wavelength of $13.62\mathrm{nm}$, the diffraction efficiency of the negative second order reaches 36.2%.