The structural unit (a12) is preferably a structural unit 50  represented by general formula (al2-1) shown below.  hydroxyl group is substituted with an acid-dissociable group  or a substituent containing an acid-dissociable group.  Examples of the acid-dissociable group that substitutes the  hydrogen atom of the hydroxyl group include the same acid› dissociable groups as those described above, and of these, a  tertiary alkyl ester-type acid-dissociable group or an acetal› type acid-dissociable group is preferable, and an acetal-type  acid-dissociable group is more preferable.  Examples of the substituent containing an acid-dissociable  group include groups composed of an acid-dissociable group  and a divalent linking group. Examples of this divalent link› ing group include the same divalent linking groups as those  mentioned above for Y 2  in formula (al-3), and a group in  which the terminal structure on the acid-dissociable group- side of the group is a carbonyloxy group is particularly desir› able. In such a case, the acid-dissociable group is preferably  bonded to the oxygen atom (---0-) of the carbonyloxy  group.  As the substituent containing an acid-dissociable group,  groups represented by a formula R$^{11}$’---0-C(=O)-and  groups represented by a formula R$^{11}$’-O----C(=O)-R 12 ’› are preferable. In these formulas, R 11 ’ represents an acid› dissociable group, and R 12 ’ represents a linear or branched  alkylene group.  The acid-dissociable group for R  11 ’ is preferably a tertiary  alkyl ester-type acid-dissociable group or an acetal-type acid› dissociable group, and is more preferably a tertiary alkyl  ester-type acid-dissociable group. Preferred examples of the  tertiary alkyl ester-type acid-dissociable group include the  aforementioned aliphatic branched acid-dissociable groups  represented by the formula ----C(R$^{71 }$)(R$^{72}$)(R 73 ), groups rep› resented by formulas (1-1) to (1-9), and groups represented  by formulas (2-1) to (2-6).  Examples of the alkylene group for R 12 ’ include a methyl› ene group, ethylene group, trimethylene group, tetramethyl› ene group and 1, 1-dimethy lethy lene group. A linear alky lene  group is preferable as R 12 ’.  There are no particular limitations on the "substituent other  than a hydroxyl group" that may substitute a hydrogen atom  bonded to the benzene ring, and examples include a halogen  atom, an alkyl group of 1 to 5 carbon atoms, a halogenated  alkyl group of 1 to 5 carbon atoms, and a carboxyl group.  Examples of the halogen atom include a fluorine atom, chlo› rine atom, bromine atom and iodine atom, and a fluorine atom  is particularly desirable.  In the formula, R represents a hydrogen atom, an alkyl group  of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5  There are no particular limitations on the "substituent other  than a hydroxyl group" that may substitute a hydrogen atom  bonded to the naphthalene ring, and examples include a halo› gen atom, an alkyl group ofl to 5 carbon atoms, a halogenated  alkyl group of 1 to 5 carbon atoms, and a carboxyl group.  Examples of the halogen atom include a fluorine atom, chlo› rine atom, bromine atom and iodine atom, and a fluorine atom  is particularly desirable.  In the structural unit (a13), examples of the acid-disso› ciable group or substituent containing an acid-dissociable  group that substitutes the hydrogen atom of the hydroxyl  group include the same groups and substituents as those men› tioned above within the description of the structural unit  (a12).  The structural unit (a13) is a structural unit derived from a  vinyl(hydroxynaphthalene) in which the hydrogen atom  bonded to the carbon atom on the a-position may be substi› tuted with a substituent, in which the hydrogen atoms bonded  to the naphthalene ring may be substituted with a substituent  other than a hydroxyl group, and in which the hydrogen atom  of the hydroxyl group is substituted with an acid-dissociable  group or a substituent containing an acid-dissociable group.  Examples of the alkyl group and halogenated alkyl group  for Rc include the same groups as those mentioned above for  the alkyl group and halogenated alkyl group for R.  {Structural Unit (a13)}  Examples of the halogen atom for Rc include a fluorine  atom, chlorine atom, bromine atom and iodine atom, and a  fluorine atom is particularly desirable.  There are no particular limitations on the bonding  position(s) of the oxc group(s) to the benzene ring in the  formula. When px represents 1, the OXc group is preferably  bonded to the para-position ( 4th position) relative to the posi› tion to which the a-position carbon atom (the carbon atom  bonded to R) is bonded. When px represents an integer of 2 or  greater, any arbitrary combination of bonding positions may  be used.  When px represents 2 or 3, the plurality ofXc groups in the  formula may be the same or different. For example, one of the  xc groups may be an acid-dissociable group or a substituent  containing an acid-dissociable group, and the other one or  two xc groups may be hydrogen atoms. Similarly, when qx  represents an integer of 2 to 4, the plurality of Rc groups may  be the same or different.  px represents an integer of 1 to 3, and is preferably 1.  In formula (al2-1), R is the same as defined above.  Examples of the acid-dissociable group and the substituent  containing an acid-dissociable group for xc include the same  groups as those mentioned above.  carbon atoms, px represents an integer of 1 to 3 and qx  represents an integer of  O  to 4, provided that px+qx is an  integer of 1 to 5. Each of the px xc groups independently  represents a hydrogen atom, an acid-dissociable group or a  substituent containing an acid-dissociable group, provided  that at least one xc group represents an acid-dissociable group  or a substituent containing an acid-dissociable group. Each of  the qx Rc groups independently represents a halogen atom, an  alkyl group of 1 to 5 carbon atoms or a halogenated alkyl  group of 1 to 5 carbon atoms.  US 9,164,380 B2  60  59  [Chemical Formula 20]  (a12-1) 