Theoretical study on trade-off relationships between resolution, line edge roughness, and sensitivity in resist processes for semiconductor manufacturing by extreme ultraviolet lithography

Abstract

Extreme ultraviolet (EUV) lithography will be soon applied to high-volume production of semiconductor devices. A high numerical aperture tool is planned to extend the use of EUV lithography. The trade-off relationships between resolution, line edge roughness (LER), and sensitivity are a significant concern for the extendability of EUV lithography. In this study, the dependences of chemical gradient (an indicator of LER) on the half-pitch of line-and-space patterns, the sensitizer concentration, and the effective reaction radius for deprotection were investigated using a simulation on the basis of the sensitization and reaction mechanisms of chemically amplified EUV resists. The relationships between resolution, LER, and sensitivity were formulated. In sub-10 nm half-pitch resolution region, the effect of thermalized electrons became clear. The increase of sensitizer concentration and/or effective reaction radius is required for the suppression of the effect of thermalized electrons.