US 2020/0192221 Al  62  Jun.  18,2020  -continued  [0129]  The compound having the anion of formula (ID)  has a sufficient acid strength to cleave acid labile groups in  the base polymer because it is free of fluorine at a-position  of sulfa group, but has two trifluoromethyl groups at 3-po› sition. Thus the compound is a useful PAG.  [0130]  A compound having the formula (2) is also a useful  PAG.  (2)  [0131]  In formula (2), R 201  and R 202  are each indepen› dently a C$_{1 }$-C$_{30 }$monovalent hydrocarbon group which may  contain a heteroatom. R$^{203 }$is a C$_{1}$-C$_{30 }$divalent hydrocarbon  group which may contain a heteroatom. Any two of R 201 ,  R$^{202 }$and R$^{203 }$may bond together to form a ring with the  sulfur atom to which they are attached. L is a single bond,  ether bond or a C$_{1 }$-C$_{20 }$ divalent hydrocarbon group which  may contain a heteroatom.  XA, XB, Xe  and  xn  are each  independently hydrogen, fluorine or trifluoromethyl, with  the proviso that at least one  ofXA, XB, Xe  and  xn  is fluorine  or trifluoromethyl, and k is an integer of Oto 3.  [0132]  The monovalent hydrocarbon group may be  straight, branched or cyclic. Examples thereof include  straight or branched alkyl groups such as methyl, ethyl,  propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl,  tert-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, 2-ethylhexyl;  monovalent saturated cyclic hydrocarbon groups such as  cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentyl› ethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl,  cyclohexylbutyl, norbormyl, oxanorbornyl, tricyclo[5.2.1.  0 2 • $^{6}$]decanyl, adamantyl; aryl groups such as phenyl, naph› thyl and anthracenyl. Also included are the foregoing groups  in which some hydrogen is substituted by a moiety contain› ing a heteroatom such as oxygen, sulfur, nitrogen or halogen,  or in which some carbon is replaced by a moiety containing  a heteroatom such as oxygen, sulfur or nitrogen, so that the  group may contain a hydroxyl, cyano, carbonyl, ether bond,  ester bond, sulfonic acid ester bond, carbonate bond, lactone  ring, sultone ring, carboxylic acid anhydride or haloalkyl  moiety.  [0133]  The divalent hydrocarbon group may be straight,  branched or cyclic. Examples thereof include straight or  branched alkanediyl groups such as methylene, ethylene,  propane-1,3-diy  1,  butane-1,4-diy  1,  pentane-1, 5-diy  1,  hexane- 1,6-diy  l,  heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl,  [0135]  In formula (2’), L is as defined above. "A" is  hydrogen or trifluoromethyl, preferably trifluoromethyl.  R 301 , R $^{302 }$and R$^{303 }$are each independently hydrogen or a  C$_{1 }$-C$_{20 }$monovalent hydrocarbon group which may contain a  heteroatom. The monovalent hydrocarbon group may be  straight, branched or cyclic and examples thereof are as  exemplified above for R  107 . The subscripts x and y each are  an integer of 0 to 5, and z is an integer of 0 to  4.  [0136]  Examples of the PAG having formula (2) are  shown below, but not limited thereto. Herein "A" is as  defined above.  decane-1, 10-diyl, undecane-1, 11-diyl, dodecane-1, 12-diyl,  tridecane-1, 13-diyl, tetradecane-1, 14-diyl, pentadecane-1,  15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl; diva› lent saturated cyclic hydrocarbon groups such as cyclopen› tanediyl,  cyclohexanediyl,  norbornanediyl,  and  adamantanediyl; and divalent unsaturated cyclic hydrocar› bon groups such as phenylene and naphthylene. Also  included are the foregoing groups in which some hydrogen  is substituted by an alkyl group such as methyl, ethyl,  propyl, n-butyl or tert-butyl, or in which some hydrogen is  substituted by a moiety containing a heteroatom such as  oxygen, sulfiur, nitrogen or halogen, or in which some  carbon is replaced by a moiety containing a heteroatom such  as oxygen, sulfur or nitrogen, so that the group may contain  a hydroxyl, cyano, carbonyl, ether bond, ester bond, sulfonic  acid ester bond, carbonate, lactone ring, sultone ring, car› boxylic acid anhydride or haloalkyl moiety. The preferred  heteroatom is oxygen.  [0134]  Of the PAGs having formula (2), those having  formula (2’) are preferred.  (2’) 