Modification Toward Fluorine-Containing High-χ Block Copolymers and Orientation Control on Thin Films

To approach miniaturized patterns such as sub-10 nm, block copolymer (BCP) has emerged as an attractive material to overcome the size limit of the conventional lithography, where Flory-Huggins interaction parameter (χ) plays the key role to control the size. In this study, fluorine-containing high-χ BCP is newly designed which was synthesized using transesterification method. High-yield conversion was achieved using a polymeric catalyst, where the polymer dispersity remain unchanged during the transesterification. Evaluated χ was above 0.2 over the entire temperature range which is 8 fold higher than polystyrene-b-poly(methyl methacrylate) and the smallest half-pitch feature size was approximately 5 nm from 6.3 kg/mol BCP. Film experiments were demonstrated on a neutralized homopolymer mat substrate where a sub-10 nm perpendicular lamellar morphology was observed in as spun state.