20  US 9,665,002 B2  19  tially insoluble in water and alkaline developer (hydropho› bic resin), and (G) an organic acid derivative and/or fluori› nated alcohol.  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).  (B) Base Resin  (2)  ( 3 H  ’j==o  $^{0 }$\ $_{YL }$ 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.  H  Ria  (~  H  0  0  ~o  o  I  XA  H  Ria  (~  H  0  0  co  ~o  o  I  XA 