US 10,698,314 B2  123  124  and R 3 , and/or R 3  and R 4  may bond together to form a  ring, or a pair of R 1  and R 2 , R 1  and R 4 , R 2  and R 3 , or  R $^{3 }$and R 4 , taken together, may form a double bond, R  11  is a C$_{2}$ -C$_{12 }$straight, branched or cyclic alkylene group  which may contain an ether and/or ester moiety,  x- is  an anion selected from the group consisting on-, Br  $_{2}$1-,  Br1$_{2}$ - and 1$_{3}$-.  3.  The resist composition of claim  1  wherein the base  polymer is an acid labile group-free polymer.  4.  The resist composition of claim  1,  further comprising  an organic solvent.  5.  The resist composition of claim  1,  further comprising  a surfactant.  6.  A pattern forming process comprising the steps of $_{15 }$ coating the resist composition of claim  1  onto a substrate,  baking, exposing the resulting resist film to high-energy  radiation, and developing the resist film with a developer.  7.  The process of claim  6  wherein the high-energy radia› tion is ArF excimer laser of wavelength 193 nm or KrF  excimer laser of wavelength 248 nm.  8.  The process of claim  6  wherein the high-energy radia› tion is EB or EUV of wavelength 3 to 15 nm.  9.  A chemically amplified resist composition comprising  a quencher containing a quaternary ammonium salt  selected from the group consisting of a quaternary  ammonium iodide, quaternary ammonium dibromoio› dide, quaternary ammonium bromodiiodide, and qua› ternary ammonium triiodide,  wherein the acid generator is capable of generating sul› fonic acid, imidic acid or methide acid, and the base  polymer consists of  recurring units having the formula (al) or recurring units  having the formula (a2), and at least one selected from  the group consisting of  recurring units (b) having a phenolic hydroxyl group as an  adhesive group,  recurring units ( c) having another adhesive group selected  from the group consisting of hydroxyl ( other than the  foregoing phenolic hydroxyl), lactone ring, ether, ester,  carbonyl and cyano groups,  recurring units ( d) selected from the group of units  consisting of indene, benzofuran, benzothiophene, ace› naphthylene, chromone, coumarin, norbornadiene, and  derivatives thereof,  recurring units ( e) derived from compounds selected from 50  the group consisting of styrene, vinylnaphthalene,  vinylanthracene, vinylpyrene, methyleneindene, vinyl› pyridine, and vinylcarbazole, and  recurring units of at least one selected from recurring  units having the formulae  (fl) to (f3):  wherein  RA  is each independently hydrogen or methyl,  Z 1  is a single bond, phenylene,  -O-Z 11 ,  ----C(=O)› Z  12  -Z  11  -, is a C $_{1 }$-C$_{6 }$ straight, branched or cyclic  alkylene group which may contain a carbonyl, ester,  ether or hydroxyl moiety, or Z 11  is a C$_{2}$ -C$_{6 }$ straight,  branched or cyclic alkenylene group which may con› tain a carbonyl, ester, ether or hydroxyl moiety, or Z 11  is a phenylene group, Z$^{12 }$is  -0- or  -NH-,  Rs1, Rs2, Rs3, Rs4,  Rss,  Rs6, Rs7, and Rss are each  independently a C$_{1 }$-C$_{12 }$ straight, branched or cyclic  alkyl group which may contain a carbonyl, ester or  ether moiety, or R 51  R 52 , R 53 , R 54  R 55 , R 56 , R 57 , and  R 58  are each independently a  CcC$_{12 }$ aryl,  C$_{7}$ -C$_{20 }$ aralkyl, or mercaptophenyl group,  Z 2  is a single bond, -Z $^{21}$-C(=0)---0-, -Z$^{21}$---0-,  or -Z $^{21}$-0----C(=0)-, Z 21  is a C$_{1}$-C$_{12 }$ straight,  branched or cyclic alkylene group which may contain  a carbonyl, ester or ether moiety,  Z 3  is a single bond, methylene, ethylene, phenylene,  fluorinated phenylene,  ---O-Z 31 -, or ----C(=O)- wherein  RA  is each independently hydrogen or methyl, R 21  and R$^{22 }$are each independently an acid labile group, X$^{1 }$is a  single bond, phenylene, naphthylene, or a C$_{1 }$-C$_{12 }$ linking  group containing ester moiety or lactone ring, and X 2  is a  single bond or ester group,  -continued  (a2)  ~  OR22  (fl)  (f2)  R53  I  +s-Rs4  I  Rss  (fJ)  an acid generator, and  a base polymer,  (al) 