Resist composition

A resist composition comprising in admixture:

• (A) a compound which forms an acid upon exposure to active rays, in an amount of 0.01-50 parts by weight per 100 parts by weight of a component (B);
• (B) 100 parts by weight of a polymer which has at least one structural unit with a group unstable to an acid and cleaves at this group in the presence of the acid derived from the compound (A) to turn alkali-soluble and contains, as the structural unit with a group unstable to an acid, at least one structural unit selected from the group consisting of structural units represented by the following formulae (I), (II) and (III):
• ##STR13## wherein R.sup.1 and R.sup.2 are identical with or different from each other, and mean individually a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1-5 carbon atoms or a substituted alkyl group having 1-5 carbon atoms and a halogen atom as a substituent, and R.sup.3 denotes a linear acetal group, a cyclic acetal group, a carbonate group or --OR.sup.9, in which R.sup.9 is ##STR14## in which R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 are independently selected from linear alkyl groups, substituted linear alkyl groups having a halogen atom as a substituent, branched alkyl groups, substituted branched alkyl groups having a halogen atom as a substituent, cycloalkyl groups, substituted cycloalkyl groups having a halogen atom as a substituent, alkenyl groups, substituted alkenyl groups having a halogen atom as a substituent, aryl groups, substituted aryl groups having a halogen atom or a nitro group as a substituent, aralkyl groups and substituted aralkyl groups having a halogen atom or a nitro group as a substituent, or R.sup.13 and R.sup.14 may each be a hydrogen atom;
• ##STR15## wherein R.sup.4 means a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1-5 carbon atoms or a substituted alkyl group having 1-5 carbon atoms and a halogen atom as a substituent, and R.sup.5 is ##STR16## in which R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 are independently selected from linear alkyl groups, substituted linear alkyl groups having a halogen atom as a substituent, branched alkyl groups, substituted branched alkyl groups having a halogen atom as a substituent, cycloalkyl groups, substituted cycloalkyl groups having a halogen atom as a substituent, alkenyl groups, substituted alkenyl groups having a halogen atom as a substituent, aryl groups, substituted aryl groups having a halogen atom or a nitro group as a substituent, aralkyl groups and substituted aralkyl groups having a halogen atom or a nitro group as a substituent, or R.sup.13 and R.sup.14 may each be a hydrogen atom;
• and ##STR17## wherein R.sup.6 and R.sup.7 mean individually a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1-5 carbon atoms or a substituted alkyl group having 1-5 carbon atoms and a halogen atom as a substituent, and R.sup.8 is ##STR18## in which R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 and R.sup.15 are independently selected from linear alkyl groups, substituted linear alkyl groups having a halogen atom as a substituent, branched alkyl groups, substituted branched alkyl groups having a halogen atom as a substituent, cycloalkyl groups, substituted cycloalkyl groups having a halogen atom as a substituent, alkenyl groups, substituted alkenyl groups having a halogen atom as a substituent, aryl groups, substituted aryl groups having a halogen atom or a nitro group as a substituent, or R.sup.13 and R.sup.14 may each be a hydrogen atom;
• and
• (C) at least one phenolic compound selected from the group consisting of phenols, bisphenols, trisphenols, tetrakisphenols, hydroxybenzophenones, hydroxybiphenyls, hydroxybenzophenone oximes, hydroxybenzotriazoles, hydroxyacetophenones, gallic acid, hydroxystyrenes, hydroxystyrene oligomers, hydroxy-.alpha.-methylstyrenes, hydroxy-.alpha.-methylstyrene oligomers, novolak oligomers, chromones, flayones, flavonols, flavanones, oxyflavanones, isoflavans, chromans, catechins, spirobichromans, nitrophenols, cyanophenols, alkoxyphenols, halogenated phenols, and derivatives thereof, in an amount of 0.01-100 parts by weight per 100 parts by weight of the component (B);
• and
• (D) a solvent in an amount sufficient to uniformly dissolve the components (A), (B) and (C), said resist composition being positive working when developed with alkaline developer.