Jul.  30,  2020  3  US 2020/0241417 Al  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 31 -, C(=O)---0-Z 31 -, or ----C(=O)-NH› Z31-, Z 31  is a C 1 -C 6  alkanediyl group, C 2 -C 6  alkenediyl  group, phenylene group, fluorinated phenylene group, or  trifluoromethyl-substituted phenylene group, which may  contain a carbonyl moiety, ester bond, ether bond or  hydroxyl moiety. R 21  to R 28  are each independently a C 1  -C$_{20 }$ monovalent hydrocarbon group which may contain a het› eroatom, any two ofR 23 , R 24  and R 25  or any two ofR 26 , R 27  and R 28  may bond together to form a ring with the sulfur  atom to which they are attached. "A" is hydrogen or  trifluoromethyl. M- is a non-nucleophilic counter ion.  [0025]  In another aspect, the invention provides a process  for forming a pattern comprising the steps of applying the  resist composition defined herein to form a resist film on a  substrate, exposing the resist film to high-energy radiation,  and developing the exposed resist film in a developer.  [0026]  Typically, the high-energy radiation is ArF excimer  laser radiation of wavelength 193 nm, KrF excimer laser  radiation of wavelength 248 nm, EB, or EUV of wavelength  3 to 15 nm.  [0027]  The amine compound having an iodized aromatic  ring is fully absorptive to EUV due to iodine, has a sensi› tizing effect, and is quite effective for suppressing acid  diffusion by virtue of the large atomic weight of iodine.  Since the amine compound also has an acid-decomposable  tertiary ester structure, it is decomposed with acid in the  exposed region and converted to an amine compound having  a lower molecular weight. As a result, the acid in the  exposed region becomes more active and the contrast is  improved. There are obtained advantages including low  diffusion, high contrast, high sensitivity, low LWR, and  improved CDU. Thus a resist composition having a high  sensitivity, low LWR and improved CDU is designed.  [0028]  As used herein, the singular forms "a," "an" and  "the" include plural referents unless the context clearly  dictates otherwise. The notation  (Cn-Cm)  means a group  containing from n to m carbon atoms per group. As used  herein, the term "iodized" compound means an iodine› substituted compound. In chemical formulae, Me stands for  methyl, and Ac for acetyl.  [0029]  The abbreviations and acronyms have the follow› ing meaning.  [0044]  The C 1  -C 6  alkyl group may be straight, branched or  cyclic, and examples thereof include methyl, ethyl, n-propyl,  isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert› butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, and cyclo› hexyl. Examples of the alkyl moiety in the C 1  -C 6  alkoxy,  C 2 -C 6  acyloxy or C 1  -C 4  alkylsulfonyloxy group are as  exemplified above for the alkyl group of 1 to 6, 1 to 5, or 1  to 4 carbon atoms.  [0043]  In formulae (A-1) and (A-2), R 1  is hydrogen,  hydroxyl, an optionally halo-substituted C 1  -C 6  alkyl group,  optionally halo-substituted C 1  -C 6  alkoxy group, optionally  halo-substituted C 2 -C 6  acyloxy group, optionally halo-sub› stituted C 1  -C 4  alkylsulfonyloxy group, fluorine, chlorine,  bromine, amino, nitro, cyano, -NR 1 A-C(=O)-R 1$_{B,}$ or  -NR 1 A----C(=O---0-R 1$_{B,}$ $_{wherein R}$1 A is hydrogen or a  C 1  -C 6  alkyl group, and  RIB  is a C 1  -C 6  alkyl group or C 2 -C 5  alkenyl group.  [0042]  In formulae (A-1) and (A-2), Xis a single bond or  a C 1  -C$_{20 }$divalent linking group. The divalent linking group  may be straight, branched or cyclic. Examples include  straight or branched alkanediyl groups such as methylene,  ethylene, propane-1,2-diyl, propane-1,3-diyl, butane-1,2- diyl,  butane-1,3-diyl,  butane-1,4-diyl,  pentane-1,5-diyl,  hexane-1,6-diyl, heptane-I, 7-diyl, octane-1,8-diyl, nonane- 1,9-diyl, decane-1,10-diyl, undecane-1,1-diyl, and dode› cane-1,12-diyl; C 3 -C 20  divalent saturated cyclic hydrocar› bon groups such as cyclopentanediyl, cyclohexanediyl,  norbornanediyl,  and  adamantanediyl;  C 2 -C 20  divalent  unsaturated aliphatic hydrocarbon groups such as vinylene  and propene-1,3-diyl;  CcC$_{20 }$ divalent aromatic hydrocarbon  groups such as phenylene and naphthylene; and mixtures  thereof. The divalent linking group may contain an ether  bond, carbonyl moiety, ester bond, amide bond, sultone ring,  lactam ring, carbonate bond, halogen, hydroxyl moiety or  carboxyl moiety.  [0041]  The quencher contains an amine compound having  an iodized aromatic ring and a tertiary ester structure.  Specifically the amine compound has the formula (A-1) or  (A-2).  [0040]  The resist composition of the invention is defined  as comprising a base polymer and a quencher containing an  amine compound having an iodized aromatic ring and a  tertiary ester structure.  Resist Composition  Amine Compound  Advantageous Effects of Invention  DESCRIPTION OF EMBODIMENTS  [0030]  EB: electron beam  [0031]  EUV: extreme ultraviolet  [0032]  Mw: weight average molecular weight  [0033]  Mn:  number average molecular weight  [0034]  Mw/Mn: molecular weight dispersity  [0035]  GPC: gel permeation chromatography  [0036]  PEB: post-exposure bake  [0037]  PAG: photoacid generator  [0038]  LWR: line width roughness  [0039]  CDU: critical dimension uniformity  (A-1)  (A-2) 