Photoacid generators, chemically amplified resist compositions, and patterning process

A photoacid generator for chemically amplified resist compositions, having the following general formula (1a):

• wherein R which may be the same or different is a hydrogen atom, fluorine atom, chlorine atom, nitro group, or substituted or unsubstituted, straight, branched or cyclic alkyl or alkoxy group of 1 to 12 carbon atoms, n is 0 or 1, m is 1 or 2, r is an integer of 0 to 4, r′ is an integer of 0 to 5, EWG is a cyano group, nitro group or perfluoroalkyl group of 1 to 3 carbon atoms, and p is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or substituted or unsubstituted aryl group of 6 to 12 carbon atoms.

A photoacid generator for chemically amplified resist compositions, having the following general formula (1b):

• wherein R which may be the same or different is a hydrogen atom, fluorine atom, chlorine atom, nitro group, or substituted or unsubstituted, straight, branched or cyclic alkyl or alkoxy group of 1 to 12 carbon atoms, n is 0 or 1, m is 1 or 2, r is an integer of 0 to 4, r′ is an integer of 0 to 5, EWG is a cyano group, nitro group or perfluoroalkyl group of 1 to 3 carbon atoms, and q is a substituted or unsubstituted, straight, branched or cyclic alkylene group of 1 to 10 carbon atoms or substituted or unsubstituted arylene group of 6 to 18 carbon atoms.

A photoacid generator for chemically amplified resist compositions, having the following general formula (1c):

• wherein R which may be the same or different is a hydrogen atom, fluorine atom, chlorine atom, nitro group, or substituted or unsubstituted, straight, branched or cyclic alkyl or alkoxy group of 1 to 12 carbon atoms, n is 0 or 1, m is 1 or 2, r is an integer of 0 to 4, r′ is an integer of 0 to 5, and G is a hydrogen atom, substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or substituted or unsubstituted aryl group of 6 to 12 carbon atoms, or two G's taken together may form a cyclic structure with the carbon atoms to which the G's are attached.

A chemically amplified resist composition comprising

• (A) a resin which changes its solubility in an alkaline developer under the action of an acid, and
• (B) a photoacid generator in the form of an O-arylsulfonyloxime compound for chemically amplified resist compositions, capable of generating, upon exposure to ultraviolet radiation, deep ultraviolet radiation, electron beams, x-rays, excimer laser beams, gamma-rays or synchrotron radiation, an arylsulfonyloxyarylsulfonic acid having the following general formula (1′):
• wherein R which may be the same or different is a hydrogen atom, fluorine atom, chlorine atom, nitro group, or substituted or unsubstituted, straight, branched or cyclic alkyl or alkoxy group of 1 to 12 carbon atoms, n is 0 or 1, m is 1 or 2, r is an integer of 0 to 4, and r′ is an integer of 0 to 5.