Radical copolymerization of 2-trifluoromethylacrylic monomers. III. Kinetics and monomer reactivities in the copolymerization of t-butyl 2-trifluoromethylacrylate and methacrylate with styrene bearing hexafluoroisopropanol

摘要

Radical copolymerizations of t-butyl 2-trifluoromethylacrylate (TBTFMA) and styrene-bearing hexafluoroisopropanol [4-(1,1,1,3,3,3-hexafluoro-2-hydroxypropyl)-styrene (STHFA) with 2,2'-azobisisobutyronitrile were investigated in detail through the analysis of the kinetics in situ with H-1 NMR and through the determination of the monomer reactivity ratios. TBTFMA incorporation was less than 50 mol % unless its concentration in the feed was greater than 90 mol %. Furthermore, the penultimate model provided a better description of the TBTFMA-STHFA copolymerization. In contrast, t-butyl methacrylate copolymerized with STHFA according to the terminal model. The copolymerizations were simulated on the basis of the monomer reactivity ratios to calculate the feed and copolymer composition changes, sequence distributions, and so forth as a function of the initial feed ratio and conversion. The simulation results showed excellent agreement with the kinetic data. The copolymers described in this article were evaluated as chemical amplification resist polymers for the emerging field of 157-nm lithography. (C) 2004 Wiley Periodicals, Inc. [References: 25]