Inhomogeneity of photoacid generators in methacrylate-type EUV resist film studied by molecular dynamics simulations

Extreme ultraviolet (EUV) resist materials are requested simultaneously to improve the resolution, line-edge roughness (LER), and sensitivity. In a resist film, inhomogeneous structures in the nanometer region may have large effects directly on the resolution and LER and indirectly on sensitivity. In this paper, we will focus on evaluating the inhomogeneity of photoacid generators (PAGs) in a methacrylate-type EUV resist film by molecular dynamics simulations. Results show the inhomogeneity of positions and motions of PAGs in the resist film. Moreover, PAG anions show larger diffusion constants than PAG cations. These properties can be elucidated qualitatively by considering the free volumes in the resist matrix and molecular structures such as bulky phenyl groups of PAG cations and chemical properties such as the fluorine atom interaction of PAG anions. (C) 2015 The Japan Society of Applied Physics