US 2020/0192221 Al  105  Jun.  18,2020  6.  The positive resist composition of claim  1  wherein the  base polymer further comprises recurring units containing  an adhesive group selected from the group consisting of  hydroxyl, carboxyl, lactone ring, carbonate, thiocarbonate,  carbonyl, cyclic acetal, ether bond, ester bond, sulfonic ester  bond, cyano, amide,  ---0----C(=O)-S-,  and  -0----C  (=0)-NH-.  7. The positive resist composition of claim  1  wherein the  base polymer further comprises recurring units of at least  one type selected from recuring units having the formulae  (dl) to (d3):  4.  The positive resist composition of claim  1  wherein the  base polymer further comprises recurring units having a  carboxyl group in which the hydrogen is substituted by an  acid labile group and/or recurring units having a phenolic  hydroxyl group in which the hydrogen is substituted by an  acid labile group.  5.  The positive resist composition of claim  4  wherein the  recurring units having a carboxyl group in which the hydro› gen is substituted by an acid labile group and the recurring  units having a phenolic hydroxyl group in which the hydro› gen is substituted by an acid labile group are recurring units  having the formula (b 1) and recurring units having the  formula (b2), respectively,  (bl)  (b2)  (d3)  (d2)  (dl)  single bond or a C$_{1 }$-C$_{6 }$ straight or branched alkanediyl  group in which some carbon may be replaced by an  ether bond or ester bond, a is 1 or 2, and b is an integer  of Oto 4.  (a2)  wherein R$^{1 }$and R 2  are each independently a C$_{1}$-C$_{6 }$ alkyl  group, C$_{2}$-C$_{6 }$ alkenyl group orC$_{2}$ -C$_{6 }$ alkynyl group, R 1  and R 2  may bond together to form a ring with the  carbon atom to which they are attached, R 3  and R 5  are  each independently hydrogen,  a  C$_{1 }$-C$_{9 }$ straight,  branched or cyclic alkyl group, C$_{2}$ -C$_{10 }$ straight or  branched alkoxycarbonyl group, C$_{3}$-C$_{10 }$ straight or  branched alkenyloxycarbonyl group, or C$_{8}$-C$_{14 }$aralky› loxycarbonyl group, the group optionally containing an  ether bond, R 4  is a C$_{1 }$-C$_{6 }$ alkyl group, C$_{2}$ -C$_{6 }$ alkenyl  group or C$_{2}$ -C$_{6 }$ alkynyl group, the circle  Ra  is a C$_{2}$ -C$_{10 }$ alicyclic group including the nitrogen atom, and the  broken line designates a valence bond to the oxygen  atom in formula (a).  wherein  RA  is each independently hydrogen or methyl, Y 1  is a single bond, phenylene, naphthylene, or a C$_{1 }$-C$_{12 }$ linking group containing an ester bond, ether bond or  lactone ring, Y $^{2 }$is a single bond, ester bond or amide  bond, R$^{11 }$and R 12  each are an acid labile group, R 13  is  fluorine, trifluoromethyl, cyano or C$_{1 }$-C$_{6 }$ alkyl, R $^{14 }$is a  Z 1  is  a  single  bond,  phenylene,  ---O-Z 11 -,  -C(=0)---0-Z 11 - or  ----C(=0)-NH-Z 11 -,  Z 1  is a C$_{1}$-C$_{6 }$ alkanediyl group, C$_{2}$ -C$_{6 }$ alkenediyl  group, or phenylene group, which may contain a  carbonyl moiety, ester bond, ether bond or hydroxyl  moiety,  Z 2  is a single bond or a C$_{5}$-C$_{12 }$ divalent group which  may contain an ester bond, ether bond or lactone  ring,  Z 3  is a single bond, methylene, ethylene, phenylene,  fluorinated phenylene,  ---O-Z 31 -,  ----C(=0)- 0-Z31- or  -C(=0)-NH-Z 31 -, Z 31  is a  C$_{1 }$-C$_{6 }$ alkanediyl group, C$_{2}$-C$_{6 }$ alkenediyl group, or  phenylene group, which may contain a carbonyl  moiety, ester bond, ether bond or hydroxyl moiety,  Rf$^{1 }$to R:t4 are each independently hydrogen, fluorine or  trifluoromethyl, at least one of Rf 1  to R:t4 being  fluorine,  wherein  RA  is each independently hydrogen or methyl,  -continued  R23  I  +s-R24  I  R2s 