A positive resist composition includes a resin component (A) which contains an acid dissociable dissolution inhibiting group and displays increased alkali solubility under the action of acid, an acid generator component (B) that generates acid on exposure, and a compound (C) represented by a general formula (1) shown below: ##STR00001## (wherein, each R.sub.1 group and each R.sub.3 group represents, independently, a hydrogen atom, an alkyl group of 1 to 3 carbon atoms, or a cycloalkyl group of 4 to 6 carbon atoms, provided at least one of the R.sub.1 and R.sub.3 groups is a cycloalkyl group of 4 to 6 carbon atoms, n represents an integer from 1 to 3, R.sub.2 represents an alkyl group of 1 to 3 carbon atoms, and X represents an alkylene group of either 4 or 5 carbon atoms).

Disclosed is a class of novel cyanooxime sulfonate compounds represented by the general formula in which R.sup.1 and R.sup.2 are, each independently from the other, an unsubstituted or halogen-substituted monovalent aliphatic hydrocarbon group selected from the group consisting of alkyl, cycloalkyl, alkenyl and cycloalkenyl groups. The group R.sup.1 is preferably a cycloalkenyl group, e.g. 1-cyclopentenyl or 1-cyclohexenyl group, and R.sup.2 is preferably a lower alkyl group having 1 to 4 carbon atoms. The compound releases an acid by the irradiation with ultraviolet light and is useful as an acid generating agent in an acid-sensitive photoresist composition. By virtue of the high transparency of the compound to ultraviolet, high acid strength of the acid generated therefrom and good solubility of the compound in organic solvents, the photoresist composition compounded with the compound as an acid generating agent is imparted with high sensitivity to ultraviolet and capable of giving a patterned resist layer having excellent characteristics.

Disclosed is a poly(disulfonyl diazomethane) compound as a class of novel compounds represented by the general formula ##STR1## in which the subscript n is 1 to 5, each R is a monovalent hydrocarbon group and Z is a divalent hydrocarbon group. The invention also discloses a chemical-amplification positive-working photoresist composition which comprises the above mentioned poly(disulfonyl diazomethane) compound as the radiation-sensitive acid-generating agent in combination with a film-forming resin capable of being imparted with increased solubility in an aqueous alkaline solution by the interaction with an acid, such as a polyhydroxystyrene resin of which a part of the hydroxyl groups are substituted by acid-dissociable solubility-reducing groups, e.g., tert-butoxycarbonyl groups.

Proposed is a positive-working chemical-sensitization photoresist composition having advantages in respect of high resolution of patterning, high photosensitivity and orthogonal cross sectional profile of the patterned resist layer as well as in respect of little dependency of the performance on the nature of the substrate surface. The composition comprises: (A) 100 parts by weight of a film-forming hydroxyl-containing resin of a specified narrow molecular weight distribution substituted by acid-dissociable groups for a part of the hydroxyl groups which causes an increase of solubility in an aqueous alkaline solution by the interaction with an acid; and (B) from 0.5 to 20 parts by weight of a radiation-sensitive acid-generating agent which is a disulfone compound represented by the general formula in which the subscript n is 0 or 1 and R.sup.1 and R.sup.2 are each, independently from the other, a monovalent cyclic group selected from the group consisting of pyridyl group, benzoxazolyl group and aryl groups substituted by at least one amino group or dialkylamino group, such as bis(4-pyridylsulfonyl) diazomethane, bis(benzoxazolyl-2-sulfonyl) diazomethane, bis(4-dimethylaminophenylsulfonyl) diazomethane and bis(5-dimethylamino-1-naphthyl) disulfone.

Disclosed is a novel and improved photoresist composition which comprises: (A) a film-forming resinous compound which is, in the presence of an acid, subject to a change in the solubility in an alkaline solution; and (B) an acid-generating agent capable of releasing an acid by the exposure to actinic rays which is an oxime sulfonate compound represented by the general formula in which R.sup.1 and R.sup.2 are, each independently from the other, an unsubstituted or halogen-substituted monovalent aliphatic hydrocarbon group, e.g., alkyl, cycloalkyl, alkenyl and cycloalkenyl groups. By virtue of the non-aromatic nature of the component (B) as well as good solubility thereof in organic solvents and high acid strength of the acid released therefrom, the composition is highly transparent to deep ultraviolet light even when the content of the component (B) is relatively large and the photosensitivity of the composition is very high so that the photoresist composition is capable of giving a patterned resist layer having excellent characteristics.