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## Synthesis of Base Polymers (Polymers 1 to 4) 

[0163] Base polymers were prepared by combining suit› able monomers, effecting copolymerization reaction thereof in tetrahydrofuran (THF) solvent, pouring the reaction solu› tion into methanol for crystallization, repeatedly washing with hexane, isolation, and drying. The resulting polymers, designated Polymers 1 to 4, were analyzed for composition by $^{1}$H-NMR spectroscopy, and for Mw and Mw/Mn by GPC versus polystyrene standards using THF solvent. 

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## Synthesis Example 

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## Examples 1 to 30 and Comparative Examples 1 to 7 

[0164] Resist compositions were prepared by dissolving various components in a solvent in accordance with the recipe shown in Tables 1 to 3, and filtering through a filter having a pore size of0.2 µm. The solvent contained 100 ppm of surfactant Polyfox PF-636 (Onmova Solutions Inc.). The resist compositions of Examples 1 to 24, 26 to 30, and Comparative Examples 1 to 6 were of positive tone, while 

