Dynamics of Radical Ions of Fluorinated Polymer for Extreme Ultraviolet (EUV) Lithography

To realize extreme ultraviolet (EUV) lithography for mass production of semiconductor devices, enhancements of performance of chemically amplified resist have been still important issue. In EUV resist, radiation chemical reactions occur after irradiations of the EUV light. Dynamics of chemical intermediates of EUV resist after exposure to the ionizing radiations is important for understanding new resist design. Fluorinated resists have been developed for ArF, F-2, and EUV lithography. Fluorinated polymers are effective to enhance the sensitivity of the EUV resist because F atom has higher absorptivity of EUV photons. However, the fluorination effect on the radiation chemical reactions in the resist has not been clarified in detail. In this study, we investigated the dynamics of radical ions of fluorinated polymers (FPs) by pulse radiolysis method and quantum chemical calculations to clarify the reaction mechanism for EUV lithography.