PURPOSE: To produce a monodisperse copolymer which meets the requirements of a polymer for a resist material by subjecting a specific monomer and styrene to anionic polymn. and eliminating CH2OCH3 groups from the resulting copolymer.
CONSTITUTION: This monodisperse copolymer comprising structural units of formulas II and III is obtd. by subjecting a monomer of formula I and styrene to anionic copolymn. and eliminating CH2OCH3 groups from the resulting copolymer. The anionic copolymn., though can be conducted in a nonsolvent system, is pref. conducted in an org. solvent to facilitate the control of reaction rate. Eliminating CH2OCH3 groups is easily carried out by dissolving the copolymer obtd. by the copolymn. in a solvent (e.g. acetone or water) and adding an acid (e.g. hydrobromic acid) dropwise to the resulting soln. The elimination reaction causes neither the breakage of the polymer main chain nor crosslinking between the polymer molecules, resulting in a monodisperse copolymer.
YAMADA MOTOYUKI
YAGIHASHI FUJIO
ISONO HISANOBU
