US 2020/0192222 Al  147  Jun.  18,2020  group containing an ester bond or lactone ring, Y $^{2 }$is a single  bond or ester bond, R$^{31 }$and R$^{32 }$are each independently an  acid labile group, R$^{33 }$is fluorine, trifluoromethyl, cyano, a  C$_{1 }$-C$_{6 }$ alkyl, C$_{1 }$-C$_{6 }$ alkoxy, C$_{2}$ -C$_{7 }$ acyl, C$_{2}$ -C$_{7 }$ acyloxy, or  C$_{2}$ -C$_{7 }$ alkoxycarbonyl group, R$^{34 }$is a single bond or C$_{1 }$-C$_{6 }$ alkanediyl group in which some carbon may be replaced by  an ether or ester bond, c is 1 or 2, d is an integer of O to 4,  meeting lsc+ds5.  8.  The resist composition of claim  7,  further comprising  a dissolution inhibitor.  9.  The resist composition of claim  7  which is a chemically  amplified positive resist composition.  10.  The resist composition of claim  1  wherein the iodized  base polymer is free of an acid labile group.  11.  The resist composition of claim  10,  further comprising  a crosslinker.  12.  The resist composition of claim  10  which is a chemi› cally amplified negative resist composition.  13.  The resist composition of claim  1,  further comprising  an iodine-free quencher.  14.  The resist composition of claim  1,  further comprising  a surfactant.  15.  The resist composition of claim  1  wherein the iodized  base polymer further comprises recurring units of at least  one type selected from recurring units having the formulae  (gl) to (g3):  (g2)  R43  I  +s-R44  I  R45  (gl)  -continued  (g3)  R46  I  +s-R47  I  R4s  wherein  RA  is each independently hydrogen or methyl,  Z $^{1 }$is a single bond, phenylene,  -O-Z 12 -,  ----C(=O)› Z11-Z12-,  Z 11  is  ---0- or  -NH-,  Z $^{12 }$is a C$_{1}$-C$_{6 }$ alkanediyl group, C$_{2}$ -C$_{6 }$ alkenediyl group or phenylene  group, which may contain a carbonyl moiety, ester  bond, ether bond or hydroxyl moiety,  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$_{12 }$ alkanediyl  group which may contain a carbonyl moiety, ester bond  or ether bond,  Z 3  is a single bond, methylene, ethylene, phenylene,  fluorinated phenylene,  ---O-Z 32 -,  or ----C(=0)› Z31-Z32-,  Z 31  is  -0- or  -NH-,  Z $^{32 }$is a C$_{1}$-C$_{6 }$ alkanediyl group, phenylene, fluorinated phenylene,  trifluoromethyl-substituted phenylene group, or C$_{2}$-C$_{6 }$ alkenediyl group, which may contain a carbonyl moi› ety, ester bond, ether bond or hydroxyl moiety,  R$^{41 }$to R$^{48 }$are each independently a C$_{1 }$-C$_{20 }$monovalent  hydrocarbon group which may contain a heteroatom,  any two ofR 43 , R $^{44 }$and R$^{45 }$or any two ofR46 , R $^{47 }$and  R$^{48 }$may bond together to form a ring with the sulfur  atom to which they are attached,  A is hydrogen or trifluoromethyl, and  Q- is a non-nucleophilic counter ion.  16.  A pattern forming process comprising the steps of  applying the resist composition of claim  1  to form a resist  film on a substrate, exposing the resist film to high-energy  radiation, and developing the exposed resist film in a devel› oper.  17.  The process of claim  16  wherein the high-energy  radiation is ArF excimer laser of wavelength 193 nm or KrF  excimer laser of wavelength 248 nm.  * * * * *  18.  The process of claim  16  wherein the high-energy  radiation is EB or EUV of wavelength 3 to 15 nm. 