Stochastic Patterning Simulation Using Attenuated Phase-Shift Mask for Extreme Ultraviolet Lithography

Abstract

In extreme ultraviolet lithography, the photon shot noise effect is a main cause of low-quality imaging characteristics such as line edge roughness and critical dimension (CD) nonuniformity. In this study, the stochastic imaging property of an attenuated phase-shift mask (PSM) was evaluated, and the results showed that "informative" photons from the first order diffraction are essential for mitigating the photon shot noise effect. This structure exhibits a reflectivity of similar to 6% at the absorber stack and a phase shift of 180 degrees at 13.5 nm wavelength. The improved stochastic patterning properties of the PSM were compared with those of a conventional binary intensity mask. (c) 2013 The Japan Society of Applied Physics