Synthesis and Evaluation of Adamantane-Containing Fluorinated Block Copolymers for Resist Modifiers in Immersion Lithography

The fluorinated block copolymer containing 2-methyl-2-adamantyl methacrylate (adMM) and perfluoroalkyl methacrylate (Zonyl ) was synthesized via atom transfer radical polymerization (ATRP) using a copper catalyst. High reactivity of adMM was observed. AdMM was polymerized even at room temperature and the polymer which with narrow polydispersity was observed. Fluorinated homopolymer (PZonyl ) and random copolymer (PadMM-γ-PZonyl ) were also synthesized. The polymers were added to the resist model polymer and the relationship between polymer structure and film characteristics were investigated such as hydrophobicity and development behavior. The fluorinated polymers (0-1 wt%), photoacid generator (PAG) (0.2 wt%) and the resist model polymer (9-10 wt%) were dissolved in α,α,α-trifluorotoluene (TFT) and the blend polymer films prepared on Si wafer. The film containing PadMM-b-PZonyl showed good hydrophobicity and resist performance compared with films containing the other polymer because self-segregation was promoted with the block copolymer and the low surface energy of perfluoroalkyl group. It is expected that adMM units in fluorinated additives increase resist performance.