US 9,513,547 B2  38  37  acid when irradiated with actinic rays or radiation into a  polymer main chain or side chain; for example, compounds  described in U.S. Pat. No. 3,849,137A, DE3914407,  JP1988-26653A (JP-S63-26653A), JP1980-164824A (JP› S55-164824A), JP1987-69263A (JP-S62-69263A), JP1988- 146038A (JP-S63-146038A), JP1988-163452A (JP-S63- 163452A), JP1987-153853A (JP-S62-153853A), JP1988- 146029A (JP-S63-146029A), and the like.  Furthermore, use can also be made of compounds gener› ating an acid upon being irradiated with light, described in  U.S. Pat. No. 3,779,778A and EP126,712B.  As the acid generator (B), examples of preferred com› pounds among the compounds generating acid upon decom› posing caused by irradiation with actinic rays or radiation  include compounds represented by the following general  formulae  (ZI), (ZII),  and  (ZIII).  Rd$_{1 }$ represents a hydrogen atom, or an alkyl group, and  may form a ring structure with bonded alkyl groups and aryl  groups.  The organic groups of Rc$_{1 }$ to Rc$_{3 }$ may be an alkyl group  in which the first position is substituted with a fluorine atom,  or a fluoroalkyl group, or a phenyl group substituted with a  fluorine atom or a fluoroalkyl group. By having the fluorine  atom or the fluoroalkyl group, the acidity of the acid  generated by light irradiation increases and sensitivity is  improved. When the carbon atoms in Rc$_{1 }$ to Rc$_{3 }$ number 5  or more, at least a single carbon atom is preferably substi- tuted with a hydrogen atom, and the number of hydrogen  atoms is more preferably greater than that of the fluorine  atoms. By not having a perfluoroalkyl group having 5 or  more carbon atoms, the ecological toxicity is reduced.  The organic group as R$_{201}$, R 202 , and R $_{203 }$generally has  1  to 30 carbon atoms, and preferably  1  to 20 carbon atoms.  Further, two members of R$_{201 }$ to R$_{203 }$ may be bonded to  each other to form a ring structure, and the ring may contain  an oxygen atom, a sulfur atom, an ester bond, an amide bond  or a carbonyl group.  Examples of the group formed by the combination of two  members of R$_{201 }$ to R$_{203 }$ include an alkylene group (for  example, a butylene group and a pentylene group).  Specific examples of the organic groups as R$_{201}$ , R $_{202 }$and  R$_{203 }$include the corresponding groups in compounds (ZI-1)  and (ZI-2) which will be described later.  Moreover, the compound may be a compound having a  plurality of structures represented by the general formula  (ZI).  For example, the compound may be a compound  having a structure where at least one of R$_{201 }$ to R$_{203 }$ in the  compound represented by the general formula  (ZI)  is bonded  to at least one of R$_{201 }$ to R$_{203 }$ in another compound repre- sented by the general formula  (ZI).  As the component (Zl), the compounds (ZI-1) and (ZI-2)  described below are more preferred.  The compound (ZI-1) is an arylsulfonium compound  where at least one ofR$_{201 }$to R$_{203 }$in the general formula  (ZI)  is an aryl group, that is, a compound having an arylsulfo- nium as the cation.  In the arylsulfonium compound, all ofR$_{201 }$to R$_{203 }$may be  an aryl group or a part ofR$_{201 }$to R$_{203 }$may be an aryl group,  with the remaining ones being an alkyl group.  Examples of the arylsulfonium compound include a tri› arylsulfonium compound, a diarylalkylsulfonium com› pound, and an aryldialkylsulfonium compound.  The aryl group of the arylsulfonium compound is prefer› ably an aryl group such as a phenyl group, a naphthyl group,  or a fluorene group, a heteroaryl group such as an indole  residue, or a pyrrole residue is preferred, and a phenyl group  or an indole residue is more preferred. In the case where the  arylsulfonium compound has two or more aryl groups, these  two or more aryl groups may be the same as or different from  each other.  The alkyl group which is present, as necessary, in the  arylsulfonium compound is preferably a linear, branched or  cyclic alkyl group having  1  to 15 carbon atoms, and  examples thereof include a methyl group, an ethyl group, a  propyl group, an n-butyl group, a sec-butyl group, at-butyl  group, a cyclopropyl group, a cyclobutyl group, and a  cyclohexyl group.  The aryl group, and alkyl group ofR$_{201 }$to R$_{203 }$may have,  as the substituent, an alkyl group (for example, having  1  to  15 carbon atoms), an aryl group (for example, having 6 to  14  carbon atoms), an alkoxy group (for example, having  1  to 15  carbon atoms), a halogen atom, a hydroxyl group or a  phenylthio group. The substituent is preferably a linear,  In the formulae AN! to AN3, Rc$_{1 }$ to Rc$_{3 }$ each indepen› dently represent an organic group. The organic groups of  Rc$_{1 }$ to Rc$_{3 }$ include ones having  1  to 30 carbon atoms,  preferably alkyl groups which may be substituted, monocy› clic or polycyclic cycloalkyl groups, heteroatom-containing  cyclic groups, an aryl group, or a group in which a plurality  of these are linked by a single bond or a linking group such  as, -0-, -CO$_{2}$ -, -S-, -SO 3 -, or -SO $_{2}$N(Rd$_{1}$ )-.  Furthermore, the organic groups may form a ring structure  with other bonded alkyl groups and aryl groups.  In the above-described general formula  (ZI),  R$_{201}$, R 202  and R$_{203 }$ each independently represent an organic group.  z- represents  a  non-nucleophilic  anion,  preferred  examples thereof including a sulfonate anion, a bis (alkyl› sulfonyl) amide anion, a tris (alkylsulfonyl) methide anion,  BF4-, PF6-, SbF6-, or the like, and is preferably an organic  anion containing a carbon atom. Preferable examples of the  organic anions include the organic anions shown in the  formulae AN! to AN3 below.  [Chem. 23]  [Chem. 24]  R202  I  z- R201-s+-R203  (ZII)  (ZIii)  AN!  El  Rc1-SO3  AN2  Rc1SO2  \NEl  I  Rc2SO2  AN3  Rc1SO2  \  Rc 2 SO 2 -CEl  I  Rc3SO2 