US 9,097,971 B2  116  115  -continued  1 to 5 carbon atoms; R 81  represents an alkyl group; R 82  represents a group which forms an aliphatic monocyclic  group with the carbon atom to which R $^{82 }$is bonded; R  83  represents a branched alkyl group; R$^{84 }$represents a group  which forms an aliphatic polycyclic group with the carbon  atom to which R$^{84 }$is bonded; R$^{85 }$represents a linear alkyl  group ofl to 5 carbon atoms; R$^{15 }$andR$^{16 }$each independently  represents an alkyl group; Y 2  represents a divalent linking  group; and X $^{2 }$represents an acid dissociable group.  In the formulae, R, Y 2  and X 2  are the same as defined  above.  In general formula (al 1-0-11), as the alkyl group for R 81 ,  the same alkyl groups as those described above for R$^{14 }$in  formulae (1-1) to (1-9) can be used, preferably a methyl  group, an ethyl group or an isopropyl group.  As the aliphatic monocyclic group formed by R $^{82 }$and the  carbon atoms to which R  82  is bonded, the same aliphatic  cyclic groups as those described above for the aforemen› tioned tertiary alkyl ester-type acid dissociable group and  which are monocyclic can be used. Specific examples include  groups in which one or more hydrogen atoms have been  removed from a monocycloalkane. The monocycloalkane is  preferably a 3- to I I-membered ring, more preferably a 3- to  8-membered ring, still more preferably a 4- to 6-membered  ring, and most preferably a 5- or 6-membered ring.  The monocycloalkane may or may not have part of the  carbon atoms constituting the ring replaced with an ether  bond  (---0-).  Further, the monocycloalkane may have a substituent such  as an alkyl group of 1 to 5 carbon atoms, a fluorine atom or a  fluorinated alkyl group of 1 to 5 carbon atoms.  As an examples ofR $^{82 }$constituting such an aliphatic mono› cyclic group, a linear alky lene group which may have an ether  bond  (---0-) interposed between the carbon atoms can be  given.  Specific examples of structural units represented by gen- era! formula (all-0-11) include structural units represented  by the aforementioned formulas (al-1-16) to (al-1-23), (al- 1-27) and (al-1-31). Among these, a structural unit repre› sented by general formula (all-1-02) shown below which  includes the structural units represented by the aforemen› tioned formulas (al-1-16), (al-1-17), (al-1-20) to (al-1-23),  (al-1-27), (al-1-31), (al-1-32) and (al-1-33) is preferable.  Further, a structural unit represented by general formula ( al 1- 1-02’) shown below is also preferable.  In the formulas, h represents an integer of 1 to 4, and  preferably 1 or 2.  [Chemical Formula 51]  In general formula (al 1-0-15), Rand R$^{84 }$are the same as  defined above. R$^{15 }$andR$^{16 }$are the same as R$^{15 }$andR$^{16 }$in the  aforementioned general formulae (2-1) to (2-6), respectively.  Specific examples of structural units represented by gen› eral formula (all-0-14) include structural units represented  by the aforementioned formulae (al-1-35) and (al-1-36)  which were described above as specific examples of the struc› tural unit represented by general formula (al-1).  In general formula (al 1-0-14), Rand R$^{82 }$are the same as  defined above. R$^{15 }$andR$^{16 }$are the same as R$^{15 }$andR$^{16 }$in the  aforementioned general formulae (2-1) to (2-6), respectively.  Further, a compound in which the aliphatic polycyclic  group formed by R $^{84 }$and the carbon atom to which R $^{84 }$is  bonded is a "group in which one or more hydrogen atoms  have been removed from tetracyclododecane" is also prefer- able, and a compound represented by the aforementioned  formula (al-1-8), (al-1-9) or (al-1-30) is also preferable.  As the structural unit ( al 1-0-13 ), a structural unit in which  the aliphatic polycyclic group formed by R $^{84 }$and the carbon  atom to which R $^{84 }$is bonded is a 2-adamantyl group is pref› erable, and a structural unit represented by the aforemen- tioned formula (al-1-1) or (al-1-2) is particularly desirable.  Specific examples of structural units represented by gen- eral formula (all-0-13) include structural units represented  by the aforementioned formulas (al-1-1), (al-1-2) and (al- 1-7) to (al-1-15) which were described above as specific  examples of the structural unit represented by general for- mula (al-1).  As the linear alkyl group for R 85 , the same linear alkyl  groups as those described above for R$^{14 }$in the aforemen› tioned formulas (1-1) to (1-9) can be mentioned, and a methyl  group or an ethyl group is particularly desirable.  In general formula (al 1-0-13), Rand R$^{84 }$are the same as  defined above.  As the structural unit (al 1-0-12), a structural unit in which  the aliphatic polycyclic group formed by R  $^{84 }$and the carbon  atom to which R $^{84 }$is bonded is a 2-adamantyl group is pref› erable, and a structural unit represented by the aforemen› tioned formula (al-1-26) is particularly desirable.  Specific examples of structural units represented by gen› eral formula (all-0-12) include structural units represented  by the aforementioned formulas (al-1-1-26) and (al-1-28) to  (al-1-30).  As the aliphatic polycyclic group formed by R $^{84 }$and the  carbon atoms to which R $^{84 }$is bonded, the same aliphatic  cyclic groups as those described above for the aforemen› tioned tertiary alkyl ester-type acid dissociable group and  which are polycyclic can be used.  In general formula (al 1-0-12), as the branched alkyl group  for R 83 , the same alkyl groups as those described above for  R $^{14 }$in formulas (1-1) to (1-9) which are branched can be used,  and an isopropyl group is particularly desirable.  In the formulae, Rand R $^{81 }$are the same as defined above;  and h represents an integer of 1 to 4.  (all-1-02)  (all-1-02’) 