Extreme ultraviolet multilayer film reflection type single-level diffraction grating

The invention provides an extreme ultraviolet multilayer film reflection type single-level diffraction grating. The extreme ultraviolet multilayer film reflection type single-level diffraction grating is used for a condition that a wavelength of an incident light wave is an extreme ultraviolet wave band. The grating comprises, from bottom to top, a substrate, a Mo-Si multilayer periodic thin film, a silicon thin film, and a metal thin film. A single-level diffraction grating pattern is formed in the metal thin film, and is formed by a plurality of reflection grating lines, which are formed by a plurality of hexagons having specific side lengths. The diffraction grating provided by the invention is used to overcome occurrence of a spectral level superposition phenomenon, and therefore an interference of a high level diffraction peak on +-1 level diffraction peak during a spectrum unfolding process is prevented.