Attenuated phase-shift mask for mitigation of photon shot noise effect in contact hole pattern for extreme ultraviolet lithography

In extreme ultraviolet lithography (EUVL), insufficient light source power is the biggest concern for high-volume manufacturing. Additionally, the photon shot noise (PSN) effect is believed to be the main source of degradation in various aspects of imaging performance. In this study, we propose an attenuated phase-shift mask (PSM) as a solution to both of these issues, yielding improved mask performance for the printing of small contact hole (C/H) patterns. Our PSM shows superior imaging performance over that of a binary intensity mask. We speculate that the stochastic imaging characteristics are improved by the enhanced diffraction efficiency of the PSM.This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Korean government (MSIP) (Grant No. 2011-0028570). We wish to convey our appreciation to KLA-Tencor for providing the PROLITHTM software