content_image/903441.jpg content_image/903449.jpg
points measured, 30 value computed) was determined and reported as LWR (nm). The results are shown in Table 11. 

<img src='content_image/903441.jpg'>

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. 

## 7) EB Writing Test after Anti-Charging Film Coating 

## Examples 5-1 to 5-7 and Comparative Examples 5-1 to 5-4 

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. 

The resist pattern was evaluated. The resist pattern- bearing wafer was observed under a TD-SEM. The optimum 

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. 

<img src='content_image/903449.jpg'>

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 

