content_image/894784.jpg content_image/894783.jpg content_image/894785.jpg
Comparative polymer 1 was synthesized in the same manner as in Synthesis Example 2. 

Copolymerization Composition Ratio (Mole Ratio) methacrylic acid 3-isopropyl-3-cyclopentyl ester:meth- acrylic acid 3-hydroxy-1-adamantyl ester:methacrylic acid 2-oxooxolan-3-yl ester=0.50:0.10:0.40 

Weight average molecular weight (Mw)=9,300 

Molecular weight distribution (Mw/Mn)=l.82 

This polymer compound was named Comparative poly› mer 1. 

<img src='content_image/894784.jpg'>

Comparative polymer 2 was synthesized in the same manner as in Synthesis Example 2. 

Copolymerization Composition Ratio (Mole Ratio) methacrylic acid l-(adamantan-l-yl)-1-methylethyl ester:4- tert-amy loxystyrene:methacry lie acid 4-hydroxypheny 1 ester:methacrylic acid 3-oxo-2, 7-dioxatricyclo[ 4.2.1.0 4 • 8 ] nonan-9-yl ester:PAG monomer 2=0.20:0.20:0.20:0.25:0.15 

Weight average molecular weight (Mw)=7,700 

Molecular weight distribution (Mw/Mn)=l.89 

<img src='content_image/894783.jpg'>

-continued 

This polymer compound was named Comparative poly› mer 2. 

<img src='content_image/894785.jpg'>

The polymer compounds (Polymers 1 to 6 and Compara› tive polymers 1 and 2) thus synthesized were each dissolved in a solvent containing 100 ppm of a surfactant, FC-4430 available from Sumitomo 3M, Ltd., with the composition shown in Table 1 to form solutions. The solutions were filtered through a 0.2-µm filter to prepare resist compositions (Examples 1 to 6 and Comparative Examples 1 and 2). 

The components shown in Table 1 are as follows. 

Polymers 1 to 6: compounds obtained in Synthesis Examples 2-1 to 2-6 

Comparative polymers 1 and 2: compounds obtained in Comparative Synthesis Examples 1 and 2 

Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) 

CyH (cyclohexane) 

GBL (y-butyrolactone) 

Acid generator: PAG 1, PAG 2 (shown by the following structural formulae) 

## Preparation of Resist Composition 

