EUV interferometric lithography and structural characterization of an EUV diffraction grating with nondestructive spectroscopic ellipsometry

In this study, we constructed an exposure platform to perform extreme ultraviolet interferometric lithography (EUVIL) exposure. This platform can be used to expose 1D and 2D gratings, simulating the line/space and contact/hole patterns, respectively. A transmission grating and an achromatic setup were utilized in the exposure. A simple and nondestructive optical characterization approach based on spectroscopic ellipsometry was proposed to characterize the structure of an EUV transmission grating. The optical behavior of a grating was analyzed by rigorous coupled-wave analysis (RCWA). The preliminary exposure results were obtained using the constructed exposure platform.