content_image/909880.jpg content_image/909881.jpg content_image/909885.jpg
## Examples 1 to 12 and Comparative Examples 1 to 3 

[0207] Positive resist compositions were prepared by dis› solving components in a solvent in accordance with the recipe shown in Table 1, and filtering through a filter having a pore size of 0.2 The solvent contained 100 ppm of surfactant FC-4430 (3M). Notably, a carboxylic acid was added in such an amount that a molar ratio of carboxyl group on the carboxylic acid to nitrogen-containing group on the polymer was 1: 1. 

[0208] The components in Table 1 are as identified below. 

Organic Solvents: 

[0209] PGMEA (propylene glycol monomethyl ether acetate) 

[0210] DAA (diacetone alcohol) Acid generator: PAG-1 of the following structural formula Quencher: Q-1 of the following structural formula 

<img src='content_image/909880.jpg'>

## [2] Preparation and Evaluation of Resist Composition 

<img src='content_image/909881.jpg'>

<img src='content_image/909885.jpg'>

[0211] EUV Lithography Test 

[0212] Each of the resist compositions in Table 1 was spin coated on a silicon substrate having a 20-nm coating of silicon-containing spin-on hard mask SHB-A940 (Shin-Etsu Chemical Co., Ltd., Si content 43 wt%) and prebaked on a hotplate at 105° C. for 60 seconds to form a resist film of 50 nm thick. Using an EUV scanner NXE3300 (ASML, NA 0.33, a0.9/0.6, quadrupole illumination), the resist film was exposed to EUV through a mask bearing a hole pattern at a pitch 46 nm (on-wafer size) and +20% bias. The resist film was baked (PEB) on a hotplate at the temperature shown in Table 1 for 60 seconds and developed in a 2.38 wt% TMAH aqueous solution for 30 seconds to form a hole pattern having a size of 23 nm. [0213] The resist pattern was observed under CD-SEM (CG-5000, Hitachi High-Technologies Corp.). The exposure dose that provides a hole pattern having a size of 23 nm is reported as sensitivity. The size of 50 holes was measured, from which a size variation (3a) was computed and reported as CDU. 

[0214] The resist composition is shown in Table 1 together with the sensitivity and CDU of EUV lithography. 

