US 10,754,248 B2  131  132  A mixed solution of a photo acid generator (PAG-4) (6.7 30  g), a 3,248 g/mol fluoro sulfonate sodium salt (1-6) (39.0 g),  methylisobutylketone (50 g), and pure water (30 g) was  stirred for 10 minutes to dispense an organic layer. The  obtained organic layer was cleaned with pure water (20 g) 3  times and concentrated under reduced pressure to remove a  35  solvent by evaporation, and subjected to decantation using  diisopropylether (30 g). Afterwards, the residue was con› centrated under reduced pressure to synthesize a target photo  acid generator (PAG-8) (7.0 g) as an oily substance (yield:  40  75%).  $^{1}$H-NMR (500 MHz, in DMSO-d$_{6}$ ): o=l.59-1.70 (6H, m),  1.83 (6H, d), 1.95 (3H, s), 3.36 (3H, s), 4.91 (2H, s), 5.11  (2H, s), 5.94 (lH, m), 7.47 (2H, m), 7.74-7.88 (12H, m) ppm  $^{19}$F-NMR (500 MHz, in DMSO-d$_{6}$ ): o=-119.5 (IF, m),  -113.5 (IF, m), -74.2 (6F, s), -72.5 (35, m) ppm  A mixed solution of a photo acid generator (PAG-3) (6.3  g), an aqueous solution (9.8 g) of a 611 g/mol ammonium  salt (5-1), methylisobutylketone (60 g) and pure water (30 g)  was stirred for 10 minutes to dispense an organic layer. The  obtained organic layer was cleaned with pure water (30 g) 5  times, and concentrated under reduced pressure to remove a  solvent by evaporation, and methylisobutylketone was  added thereto to prepare a 50 wt % methylisobutylketone  solution. After subjecting to decantation by adding hexane  (80 g) thereto, the product was dissolved into methylisobu› tylketone (40 g), and an activated carbon (0.5 g) was added  thereto and stirred for 18 hours. After the activated carbon  was filtered for removal, a filtrate was concentrated under  reduced pressure to synthesize a target photo acid generator  (PAG-9) (6.8 g) as an oily substance (yield: 94%). The  PAG-9 is a sulfonium salt having a cation represented by the  general formula (1 ’), not the sulfonium salt of the present  invention.  IR (D-ATR): v=3066, 2962, 1688, 1592, 1467, 1477,  1448, 1415, 1311, 1257, 1212, 1162, 1149, 1103, 1060, 980,  834, 791, 748, 683, 646 cm- 1  $^{1}$H-NMR (500 MHz, in DMSO-d$_{6}$ ): o=4.56 (2H, s), 6.38  (lH, s), 7.41 (2H, m), 7.74-7.79 (SH, m), 7.82-7.86 (4H, m),  8.60 (lH, br) ppm  [Synthesis Example 1-9] Synthesis of PAG-9 for  Comparison  <PAG-8>  1Qy00S~N,  0  CF3  (1-6)  (PAG-4)  (PAG-8)  (PAG-9)  (PAG-3)  F3C  CF3  I  X  -W- HO  CO2  I  (5-1)  <PAG-9>  [Synthesis Example 1-8] Synthesis of PAG-8 