Polymers for use in heat resistant photoresist composition and process for preparing the same

Claim 1

A polymer selected from the group consisting of a polymer (α) of the general formula ##STR29## a polymer (β) of the general formula ##STR30## a polymer (γ) of the general formula ##STR31## and mixtures thereof wherein R 1 to R 6 are the same or different and each represent a hydrogen atom, a (C 1 -C 4 ) alkyl group or a halogen atom, Ar represents ##STR32## wherein R 7 to R 15 are the same or different and each have the same meaning as defined with respect to R 1 to R 6 and X 1 to X 4 are the same or different and each represent --O--, --SO 2 --, --CH 2 --, --CO--, --COO--, --C(CH 3 ) 2 --, --S-- or --(CH 2 ) 2 --, Ar' represents ##STR33## wherein R 16 to R 20 are the same or different and each have the same meaning as defined with respect to R 1 to R 6 and X 5 has the same meaning as defined with respect to X 1 to X 4 , Ar" has the same meaning as defined with respect to Ar or Ar', B 1 to B 4 are the same or different and each represent --NCO or a substituent (A) formed by the reaction of --NCO with acrylic acid, methacrylic acid, a hydroxy acrylate or a hydroxy methacrylate, Q independently represents a hydrogen atom or a substituent (A'), provided that each of the rates of substituent introduction into the molecules of the polymers (α), (β) and (γ) as defined by the formulae ##EQU3## with respect to the polymer (α), the polymer (β), and the polymer (γ), respectively, is 0.1 to 20%, said substituent; (A') being a member selected from residual groups of acrylic acid chloride, methacrylic acid chloride, glycidyl acrylate and glycidyl methacrylate, said residual groups being introduced alone or in combination, and m, n and p are integers corresponding to reduced viscosities of 0.1 to 2.0 with respect to the polymer (α), the polymer (β), and the polymer (γ), respectively.