The measurement of the refractive index n and extinction coefficient k values of the EUV resist using EUV reflectivity measurement method

Our previous studies focused on ways to measure simulation parameters for EUV resists, including development parameters, Dill's C parameter, the diffusion length of PAG-derived acids, and parameters for deprotection reactions. Through EUV resist simulations based on these parameters, we examined conditions for reducing LER and improving resolution. This paper presents the results of our investigations of methods for determining the refractive index n and extinction coefficient k of photoresists for EUV light (wavelength 13.5 nm), parameters generally considered difficult to measure, and for calculating an absorption parameter known as the Dill's B parameter. We investigated three types of photoresists: polymer decomposition type resist, chemically amplified resist, and EUV metal resist.