US 10,620,533 B2  92  In formula (18), R11’ 1  and R11’ 2  are each independently  fluorine or a straight, branched or cyclic C$_{1 }$-C$_{40 }$monovalent  hydrocarbon group which may contain a heteroatom. Illus› trative examples of the monovalent hydrocarbon group are  as exemplified for R  105 . Preferably R11’ $^{1 }$and R11’$^{2 }$are fluorine  or C$_{1 }$-C$_{4 }$ straight fluorinated alkyl groups. Also,  WZ, 1  and  R11’ 2  may bond together to form a ring with the linkage:  --CF $_{2}$-S0$_{2}$ -N- -S0$_{2}$----CF $_{2}$ - to  which  they  are  attached.  It  is preferred to form a ring structure via a  fluorinated ethylene or fluorinated propylene group.  In formula (IC),  W’cl,  Wc 2  and  W" 3  are each indepen› dently fluorine or a straight, branched or cyclic C$_{1 }$-C$_{40 }$ monovalent hydrocarbon group which may contain a het› eroatom. Illustrative examples of the monovalent hydrocar› bon group are as exemplified for R  105 . Preferably wc1,  wc 2  and  wc3  are fluorine or  cl  -C4 straight fluorinated alkyl  groups. Also,  wc1 and  Wc $^{2 }$may bond together to form a ring  with the linkage:  --CF $_{2}$-S0$_{2}$-c--S0$_{2}$-CF  2 - to  which they are attached.  It  is preferred to form a ring  structure via a fluorinated ethylene or fluorinated propylene  group.  In formula (ID),  Wd  is a straight, branched or cyclic  C$_{1 }$-C$_{40 }$monovalent hydrocarbon group which may contain a  heteroatom. Illustrative examples of the monovalent hydro› carbon group are as exemplified for R  105 .  With respect to the synthesis of the sulfonium salt having  an anion of formula (ID), reference may be made to JP-A  2010-215608 and JP-A 2014-133723.  91  -continued 