content_image/885977.jpg content_image/885978.jpg content_image/885981.jpg content_image/885982.jpg
tially insoluble in water and alkaline developer (hydropho› bic resin), and (G) an organic acid derivative and/or fluori› nated alcohol. 

## (B) Base Resin 

The base resin used in the resist composition is a polymer comprising recurring units having the general formula (2) and recurring units having the general formula (3). 

<img src='content_image/885977.jpg'>

<img src='content_image/885978.jpg'>

Herein R la is hydrogen, fluorine, methyl or trifluoromethyl, za is a single bond, phenylene, naphthylene or (backbone)- C(=0)-0-Z’-, wherein Z’ is a straight C$_{1}$-C$_{10 }$ or branched or cyclic C$_{3}$ -C$_{10}$, alkylene group which may contain a hydroxyl radical, ether bond, ester bond or lactone ring, or a phenylene or naphthylene group. XA is an acid labile group. YL is hydrogen or a polar group having at least one structure selected from the group consisting of hydroxyl, cyano, carbonyl, carboxyl, ether bond, ester bond, sulfonate bond, carbonate bond, lactone ring, sultone ring, and carboxylic anhydride. 

Examples of the structure of formula (2) wherein za is a variant are illustrated below. 

<img src='content_image/885981.jpg'>

<img src='content_image/885982.jpg'>

