Optimum concentration ratio of photodecomposable quencher to acid generator in chemically amplified extreme ultraviolet resists

摘要

In chemically amplified resists used for ionizing radiations such as an extreme ultraviolet radiation, thermalized electrons and protons play important roles in pattern formation. Photodecomposable quenchers are important for 11 nm half-pitch fabrication because they capture both thermalized electrons and protons. However, their effects are complicated for the same reason. In this study, the optimum concentration ratio of photodecomposable quenchers to acid generators in terms of the trade-off relationships between resolution, line width roughness (LWR), and sensitivity was theoretically investigated, assuming line-and-space patterns of 11nm half-pitch. To suppress LWR to less than 20% critical dimension (CD), the recommended total sensitizer concentration (the sum of acid generator and photodecomposable quencher concentrations) was in the range of 0.20-0.22nm(-3). The expected sensitivities were 30-40mJ cm(-2) when the resist performance of the latest chemically amplified resists was assumed. The optimum ratio of photodecomposable quencher concentration to the total sensitizer concentration was 0.55. (C) 2015 The Japan Society of Applied Physics