Novel acid-labile polymer and resist composition

A chemically amplified resist composition consists of an acid generating agent, additive, solvent and a copolymer represented by the following formula 1 where R 1 , R 2 and R 6 are independent of each other and respectively include a hydrogen atom or an alkyl, alkoxymethylene, alkoxyethylene, phenyl, alkoxyalkylene, alkylphenyl, alkoxyphenyl, allyl, benzyl, alkylbenzyl, alkoxybenzyl containing 1 to 34 carbon atoms having or not having an hydroxy, ether, ester, carbonyl, acetal, epoxy, nitrile or aldehyde; R 5 is a hydrogen atom, an alkyl or alkoxy group containing 1 to 18 carbon atoms; R 7 is a hydrogen atom, an alkyl group containing 1 to 18 carbon atoms, an alkyl group containing alkoxy 1 to 18 carbon atoms or an alkyl group containing ester of 1 to 18 carbon atoms; R 3 and R 4 are independent and respectively include a hydrogen atom, hydroxy, nitrile, aldehyde, hydroxymethylene, and alkylcarbonyloxy, alky, hydroxyalkylene, alkoxycarbonyl, alkoxymethylene or alkoxyalkanyl group containing 1 to 18 carbon atoms; X is olefin derivatives, vinyl ether derivatives or styrene derivatives containing 1 to 40 carbon atoms, alternatively these derivatives may be comprised of hydroxy, ester, alkoxyalkyloxycarbonyl, ketone or ether; a, b, c, d, e and f are a number represented a repeating unit in the main chain, wherein a+b+c+d+e+f=1, the content of a and b are 0 to 0.7, respectively, (a+b)/(a+b+c+d+e+f)>0.3, and the content of c, d, e and f are 0 to 0.9, respectively; and n is an integer of 0 or 1.