PURPOSE: To obtain a new alkylsulfonium salt for photosensitive agent, etc., of photoresist for far-ultraviolet rays, having a 2-oxocyclic alkyl group, having high transparency to far-ultraviolet ray area and capable of effectively generating hydracid by radiation such as far-ultraviolet rays.
CONSTITUTION: A sulfide derivative expressed by the formula R3-S-R1 (R1 is 1-8C alkyl; R3 is 5-7C 2-oxo-cyclic alkyl) or the formula R2-S-R3 (R2 is 5-7C cyclic alkyl) [e.g. 2-(cyclohexylmercapto)cyclohexanone] is dissolved in a solvent such as nitromethane and the solution is made to react with a halogenated hydrocarbon (e.g. methyl iodide) expressed by the formula R2-W (W is halogen) or the formula R1-W in the presence of a compound (e.g. silver trifluoromethanesulfonate) expressed by the formula M+Y- (M+ is K+, Na+ or Ag+; Y- is counter ion) to provide the objective compound salt for photosensitive agent, etc., of photoresist for far-ultraviolet rays, expressed by the formula, having high transparency to far-ultraviolet ray area and capable of generating hydracid by far-ultraviolet rays.
NAKANO KAICHIRO
IWASA SHIGEYUKI
HASEGAWA ETSUO
