US 10,606,172 B2  92  91  12.  A resist composition comprising a base polymer and  a quencher containing an iodonium salt having the formula  (A):  which at least one hydrogen atom may be substituted  by halogen, trifluoromethyl,  C$_{1 }$-C$_{10 }$ straight, branched  or cyclic alkyl,  C$_{1 }$-C$_{10 }$ straight, branched or cyclic  alkoxy, hydroxyl, carboxyl,  C$_{2}$-C$_{10 }$ straight, branched  or cyclic alkoxycarbonyl, nitro and/or cyano; m is an 5  integer of 1 to 5, n is an integer of0 to 3, pis an integer  of 1 to 4, and q is an integer of 1 to 3.  2.  The resist composition of claim  1  wherein m is equal  to 3.  3.  The resist composition of claim  1  wherein the acid  generator is capable of generating a sulfonic acid, imide acid  or methide acid.  4.  The resist composition of claim  1,  further comprising  an organic solvent.  5.  The resist composition of claim  1  wherein the base  polymer comprises recurring units having the formula (al)  or recurring units having the formula (a2):  wherein  RA  is each independently hydrogen or methyl,  R$^{11 }$and R$^{12 }$each are an acid labile group, Y$^{1 }$is a single  bond, phenylene group, naphthylene group, or C$_{1 }$-C$_{12 }$ linking group containing an ester moiety and/or lactone  ring, and Y 2  is a single bond or ester group.  wherein R 1  is a hydroxyl group,  C$_{1}$-C$_{6 }$ straight, branched  or cyclic alkyl or alkoxy group,  C$_{2}$-C$_{6 }$ straight,  branched or cyclic acyloxy group, fluorine, chlorine,  bromine, amino, -NR$^{5}$-C(=O)-R 6 , or-NR $^{5}$----C  (=O)-O-R 6 , R 5  is hydrogen or a  C$_{1}$-C$_{6 }$ straight,  branched or cyclic alkyl group, R  6  is a  C$_{1 }$-C$_{6 }$ straight,  branched or cyclic alkyl group or  C$_{2}$ -C$_{8 }$ straight,  branched or cyclic alkenyl group, X $^{1 }$is a single bond or  a ( q+  1  )-valent  C$_{1 }$-C$_{20 }$ linking group which may contain  at least one moiety selected from ether, carbonyl, ester,  amide, sultone, lactam, carbonate, halogen, hydroxyl  and carboxyl;  X 2  is an ether, ester or amide group; R 2  and R 3  are each independently trifluoromethyl or a  C$_{6}$-C$_{10 }$ aryl,  C$_{2}$ -C$_{6 }$ alkenyl or  C$_{2}$-C$_{6 }$ alkynyl group in  which at least one hydrogen atom may be substituted  by halogen, trifluoromethyl,  C$_{1 }$-C$_{10 }$ straight, branched  or cyclic alkyl,  C$_{1 }$-C$_{10 }$ straight, branched or cyclic  alkoxy, hydroxyl, carboxyl,  C$_{2}$-C$_{10 }$ straight, branched  or cyclic alkoxycarbonyl, nitro and/or cyano; m is an  integer of  1 to 5, n is an integer of0 to 3, pis an integer  of 1 to 4, and q is an integer of 1 to 3,  wherein the base polymer further comprises recurring  units of at least one type selected from the formulae  (fl) to (f3):  6.  The resist composition of claim  5,  further comprising  a dissolution inhibitor.  7.  The resist composition of claim  5  which is a chemically  amplified positive resist composition.  8.  The resist composition of claim  1  wherein the base  polymer is free of an acid labile group.  9.  The resist composition of claim  8,  further comprising  a crosslinker.  10.  The resist composition of claim  8  which is a chemi› cally amplified negative resist composition.  11.  The resist composition of claim  1,  further comprising  a surfactant.  (al)  (a2)  ~  y2  OR12  (fl)  (f2)  R23  I  +s-R24  I  R2s  (fJ)  (A) 