US 9,097,971 B2  196  195  Preferable examples of the oxime sulfonate-based acid  generator include compounds represented by general formula  (B-2) or (B-3) shown below.  [Chemical Formula 98]  (B-2)  (B-3)  In the formula (B-2), R$^{33 }$represents a cyano group, an alkyl  group having no substituent or a halogenated alkyl group; R 34  represents an aryl group; and R$^{35 }$represents an alkyl group  having no substituent or a halogenated alkyl group.  In general formula (B-3), as the alkyl group having no  substituent and the halogenated alkyl group for R 36 , the same  alkyl group having no substituent and the halogenated alkyl  group described above for R$^{33 }$can be used.  [Chemical Formula 99]  In the formula (B-3), R$^{36 }$represents a cyano group, an alkyl  group having no substituent or a halogenated alkyl group; R 37  represents a divalent or trivalent aromatic hydrocarbon group;  R$^{38 }$represents an alkyl group having no substituent or a  halogenated alkyl group; and p" represents 2 or 3.  In general formula (B-2), the alkyl group having no sub› stituent or the halogenated alkyl group for R$^{33 }$preferably has  1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms,  and most preferably 1 to 6 carbon atoms.  As R 33 , a halogenated alkyl group is preferable, and a  fluorinated alkyl group is more preferable.  The fluorinated alkyl group for R$^{33 }$preferably has 50% or  more of the hydrogen atoms thereof fluorinated, more pref› erably 70% or more, and most preferably 90% or more.  Examples of the aryl group for R$^{34 }$include groups in which  one hydrogen atom has been removed from an aromatic  hydrocarbon ring, such as a phenyl group, a biphenyl group,  a fluorenyl group, a naphthyl group, an anthryl group, and a  phenantryl group, andheteroaryl groups in which some of the  carbon atoms constituting the ring(s) of these groups are  substituted with hetero atoms such as an oxygen atom, a  sulfur atom, and a nitrogen atom. Of these, a fluorenyl group  is preferable.  The aryl group for R$^{34 }$may have a substituent such as an  alkyl group of 1 to 10 carbon atoms, a halogenated alkyl  group, or an alkoxy group. The alkyl group and halogenated  alkyl group as the substituent preferably has 1 to 8 carbon  atoms, and more preferably 1 to 4 carbon atoms. Further, the  halogenated alkyl group is preferably a fluorinated alkyl  group.  The alkyl group having no substituent or the halogenated  alkyl group for R$^{35 }$preferably has 1 to 10 carbon atoms, more  preferably 1 to 8 carbon atoms, and most preferably 1 to 6  carbon atoms.  As R 35 , a halogenated alkyl group is preferable, and a  fluorinated alkyl group is more preferable.  In terms of enhancing the strength of the acid generated,  the fluorinated alkyl group for R$^{35 }$preferably has 50% or  more of the hydrogen atoms fluorinated, more preferably  70% or more, still more preferably 90% or more. A com› pletely fluorinated alkyl group in which 100% of the hydro› gen atoms are substituted with fluorine atoms is particularly  desirable.  Furthermore, as preferable examples, the following can be  used.  Further, oxime sulfonate-based acid generators disclosed  in Japanese Unexamined Patent Application, First Publica› tion No. Hei 9-208554 (Chemical Formulas 18 and 19 shown  in paragraphs [0012] to [0014]) and oxime sulfonate-based  acid generators disclosed in WO 2004/074242A2 (Examples  1 to 40 described at pages 65 to 86) may be preferably used.  p" is preferably 2.  Specific examples of suitable oxime sulfonate-based acid  generators include a-(p-toluenesulfonyloxyimino )-benzyl  cyanide, a-(p-chlorobenzenesulfonyloxyimino )-benzyl cya› nide, a-( 4-nitrobenzenesulfonyloxyimino )-benzyl cyanide,  a-( 4-nitro-2-trifluoromethy lbenzenesulfony loxyimino )- benzyl cyanide, a-(benzenesulfonyloxyimino )-4-chloroben› zyl cyanide, a-(benzenesulfonyloxyimino )-2,4-dichloroben› zyl  cyanide,  a-(benzenesulfonyloxyimino )-2,6- dichlorobenzyl cyanide, a-(benzenesulfonyloxyimino )-4- methoxybenzyl  cyanide,  a-(2- chloro benzenesulfony loxyimino )-4-methoxybenzy 1  cyanide, a-(benzenesulfonyloxyimino )-thien-2-yl acetoni› trile,  a-( 4-dodecylbenzenesulfonyloxyimino )benzyl  cya› nide, a-[ (p-toluenesulfony loxyimino )-4-methoxypheny l] ac- etonitrile,  a-[ ( dodecylbenzenesulfonyloxyimino )-4- methoxypheny l] acetonitrile,  a-( tosy loxyimino )-4-thieny 1  cyanide,  a-(methylsulfonyloxyimino )-1-cyclopentenyl  acetonitrile,  a-( methy lsulfony loxyimino )-1-cyclohexeny 1  acetonitrile,  a-(methylsulfonyloxyimino )-1-cycloheptenyl  acetonitrile,  a-(methylsulfonyloxyimino )-1-cyclooctenyl  acetonitrile,  a-(trifluoromethylsulfonyloxyimino )-1-cyclo› pentenyl acetonitrile, a-(trifluoromethylsulfonyloxyimino )› cyclohexyl  acetonitrile,  a-( ethylsulfonyloxyimino )-ethyl  acetonitrile, a-(propyl sulfonyloxyimino)-propyl acetoni› trile, a-( cyclohexylsulfonyloxyimino )-cyclopentyl acetoni- trile, a-( cyclohexylsulfonyloxyimino )-cyclohexyl acetoni› trile,  a-( cyclohexylsulfonyloxyimino )-1-cyclopentenyl  acetonitrile,  a-( ethylsulfonyloxyimino )-1-cyclopentenyl  acetonitrile,  a-(isopropylsulfonyloxyimino )-1-cyclopente› nyl acetonitrile, a-(n-butylsulfonyloxyimino )-1-cyclopente- nyl acetonitrile, a-( ethylsulfonyloxyimino )-1-cyclohexenyl  acetonitrile, a-(isopropylsulfonyloxyimino )-1-cyclohexenyl  acetonitrile,  a-( n-buty lsulfony loxyimino )-1-cyclohexeny 1  acetonitrile, a-(methylsulfonyloxyimino )-phenyl acetoni- trile, a-(methylsulfonyloxyimino )-p-methoxyphenyl aceto› nitrile, a-(trifluoromethylsulfonyloxyimino )-phenyl acetoni- trile,  a-(trifluoromethylsulfonyloxyimino )-p- methoxyphenyl acetonitrile, a-( ethylsulfonyloxyimino )-p› methoxyphenyl acetonitrile, a-(propylsulfonyloxyimino )-p› methylphenyl  acetonitrile,  and  a-(methyl  sulfonyl  oxyimino )-p-bromophenyl acetonitrile.  Examples of the divalent or trivalent aromatic hydrocarbon  group for R$^{37 }$include groups in which one or two hydrogen  atoms have been removed from the aryl group for R 34 .  As the alkyl group having no substituent or the halogenated  alkyl group for R 38 , the same one as the alkyl group having no  substituent or the halogenated alkyl group for R 35  can be  used. 