Synthesis, Radiation Degradation, and Electron Beam Resist Behavior of Fluorine-Containing Vinyl Polymers
ALABAMA UNIV UNIVERSITY DEPT OF CHEMISTRY
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Novel vinyl monomers containing the a-CF3 group are shown to increase the propensity toward chain scission during radiation degradation and increase the electron beam sensitivity in copolymers with methyl methacrylate and methacrylonitrile. The incorporation of 32 mo of a-trifluoro-methacrylonitrile TFMAN into polymethyl methacrylate increases sensitivity from 30 x 10 expn -5 to 3 x 10 expn 5 Ccm expn 2 at 2 keV, increases G sub 8 from 1.3 to 3.1, and decreases the etch rate from 100 to 79 Angstrommin. Similar beneficial results come from incorporating TFMAN into methacrylonitrile MCN copolymers. Polytrifluoroethyl methacrylate is a highly sensitive resist Q 2 to 3 x 10 expn -5 Ccm expn 2 but it exhibits a high etch rate 230 Angstrommin. Incorporation of 31 mo MCN into this polymer decreases the etch rate to 93 Angstrommin while preserving a high sensitivity 3-4 x 10 expn -5 Ccm expn2. The G sub 8 and G sub x values of these homo- and copolymer systems as well as the copolymer of methacrylonitrile with methyl a-fluoroacrylate MFA were obtained. The homopolymer of MFA cross-links on irradiation but its MCN copolymers tend to be positive resists with G sub x values lower than that expected if G sub x were a linear function of the MFA mole fraction.
- Physical Chemistry
- Polymer Chemistry