US 10,725,377 B2  91  92  points measured, 30 value computed) was determined and  reported as LWR (nm). The results are shown in Table 11.  The resist pattern was evaluated. The resist pattern- bearing wafer was observed under a TD-SEM. The optimum  TABLE 11  Acid  Acid  diffusion  Polymer  generator  inhibitor  Organic solvent  (pbw)  (pbw)  (pbw)  (pbw)  Example  4-1  Polymer 25  PAG-A  Q-1  PGMEA (1,780)  (80)  (4)  (4.0)  EL (1,920)  PGME (2,800)  4-2  Polymer 26  Q-1  PGMEA (1,780)  (80)  (4.0)  EL (1,920)  PGME (2,800)  4-3  Polymer 25  PAG-A  Q-1  PGMEA (5,525)  (80)  (4)  (4.0)  GBL (975)  4-4  Polymer 26  Q-1  PGMEA (5,525)  (80)  (4.0)  GBL (975)  4-5  Polymer  27  PAG-A  Q-1  PGMEA (5,525)  (80)  (8)  (8.0)  GBL (975)  4-6  Polymer  27  PAG-F  Q-1  PGMEA (5,525)  (80)  (8)  (8.0)  GBL (975)  4-7  Polymer 28  Q-1  PGMEA (5,525)  (80)  (4.0)  GBL (975)  4-8  Polymer 29  Q-1  PGMEA (5,525)  (80)  (4.0)  GBL (975)  Comparative  4-1  Polymer 25  PAG-A  Q-3  PGMEA (1,780)  Example  (80)  (4)  (4.0)  EL (1,920)  PGME (2,800)  4-2  Polymer 25  PAG-A  Q-4  PGMEA (1,780)  (80)  (4)  (2.0)  EL (1,920)  PGME (2,800)  4-3  Polymer 26  Q-3  PGMEA (1,780)  (80)  (4.0)  EL (1,920)  PGME (2,800)  4-4  Polymer 26  Q-4  PGMEA (1,780)  (80)  (2.0)  EL (1,920)  PGME (2,800)  4-5  Polymer 25  PAG-A  Q-3  PGMEA (5,525)  (80)  (4)  (4.0)  GBL (975)  4-6  Polymer  27  PAG-F  Q-3  PGMEA (5,525)  (80)  (8)  (8.0)  GBL (975)  4-7  Polymer 28  Q-3  PGMEA (5,525)  (80)  (4.0)  GBL (975)  4-8  Polymer 29  Q-3  PGMEA (5,525)  (80)  (4.0)  GBL (975)  PEB  temp. Sensitivity  Resolution LWR  (" C.)  (mJ/cm 2 )  (nm)  (nm)  120  120  120  120  120  120  120  120  120  120  120  120  120  120  120  120  42  20  4.1  48  21  3.8  43  20  4.2  49  22  3.8  41  19  4.0  33  22  4.5  47  21  3.9  32  22  4.3  41  20  6.0  no pattern  resolved  39  22  5.6  40  22  6.6  42  20  5.9  31  22  6.1  42  21  5.1  27  22  5.5  It is evident from Table 11 that the inventive negative  resist composition has improved EUV lithography perfor› mance as demonstrated by improved resolution and reduced  roughness.  Each of the negative resist compositions (R-1 to R-4,  R-24 to R-26, CR-1 to CR-4) was spin coated on a 6-inch  silicon wafer and baked at 110°  C. for 240 seconds to form  a resist film of 80 nm thick. Using a system Mark 8 (Tokyo  Electron Ltd.), an electroconductive polymer composition  was dispensed and spin coated over the resist film and baked  on a hotplate at 90°  C. for 90 seconds to form an anti› charging film of 60 nm thick. The electroconductive poly› mer composition used was a water dispersion of polysty› rene-doped polyaniline as described in Proc. of SPIE Vol.  8522, 852200-1. Using a system HL-800D (Hitachi High› Technologies Corp.) at an accelerating voltage of 50 kV, the  resist film was exposed to EB, baked (PEB) at 110°  C. for  240 seconds, and developed in a 2.38 wt% TMAH aqueous  solution for 80 seconds, thereby yielding a negative pattern.  7) EB Writing Test after Anti-Charging Film  Coating  Examples 5-1 to 5-7 and Comparative Examples  5-1 to 5-4  dose (Eop) was defined as the exposure dose (C/cm 2 )  which  provided a 1: 1 resolution of a 400-nm 1: 1 line-and-space  pattern. The resolution (or maximum resolution) was  defined as the minimum line width of a LIS pattern that  could be resolved at the optimum dose. The results are  shown in Table 12.  All the inventive resist compositions of Examples 5-1 to  5-7 comprising the sulfonium compounds having formula  (A) show satisfactory resolution. The comparative resist  compositions are inferior in resolution. This is because the  acid migrates from the anti-charging film to the resist film to  TABLE 12  Maximwn  Resist composition  Eop (µC/cm 2 )  resolution (nm)  Example  5-1 R-1  56  70  5-2 R-2  58  65  5-3 R-3  58  65  5-4 R-4  57  65  5-5 R-24  56  55  5-6 R-25  57  50  5-7 R-26  58  50  Comparative  5-1 CR-1  59  80  Example  5-2 CR-2  58  75  5-3 CR-3  58  80  5-4 CR-4  57  75 