US 10,222,696 B2  106  105  and R’c3 are fluorine or C$_{1 }$-C$_{4 }$ straight fluorinated alkyl  groups. Also,  R’c1 and R’c $^{2 }$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 5  group.  In formula (ID),  R’d  is a C$_{1 }$-C$_{4}$ ,  straight, branched or  cyclic 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.  Examples of the sulfonium salt having an anion of for- mula (ID) are shown below, but not limited thereto.  0  CF3  o~S03- s+Ph3  CF3  -continued  0  0  0 ~so,-s%,  CF3 