8  7  US 9,217,919 B2  A represents an ionic structural site capable of decompos› ing upon irradiation with an actinic ray or radiation to gener› ate an acid anion in a side chain of the resin.  2008/0081281, etc., oligomers such as calixarene and resin  structures as described below in detail.  <Resin (P)>  The resin  (P) contained in the radiation-sensitive compo› sition, in particular the positive working resist composition is  a resin having a repeating unit (A) having an ionic structural  site and capable of decomposing upon irradiation with an  actinic ray or radiation to generate an acid; and a repeating  unit  (B) having at least one phenolic hydroxyl group, a part or  all of hydrogen atoms of the hydroxyl group or groups each  being protected by a group capable ofleaving by the action of  an acid, wherein the ionic structural site of the repeating unit  (A) is a structure capable of generating an acid anion in a side  chain of the resin  (P) upon irradiation with an actinic ray or  radiation.  (1) Repeating Unit (A):  In the foregoing general formulae (III) to (V), examples of  the alkyl group represented by R$_{04 }$to Ros and R$_{07 }$ to R$_{09 }$ which is preferable include an optionally substituted alkyl  group having not more than 20 carbon atoms, for example, a  methyl group, an ethyl group, a propyl group, an isopropyl  group, an n-butyl group, a sec-butyl group, a hexyl group, a  2-ethylhexyl group, an octyl group and a dodecyl group. Of  these, an alkyl groups having not more than 8 carbon atoms is  more preferable.  Examples of the cycloalkyl group include a cycloalkyl  group which may be of a monocyclic type or a polycyclic  type. Of these, an optionally substituted cycloalkyl group of a  monocyclic type having from  3  to 8 carbon atoms, for  example, a cyclopropyl group, a cyclopentyl group and a  cyclohexyl group, is preferable.  Examples of the halogen atom include a fluorine atom, a  chlorine atom, a bromine atom and an iodine atom. Of these,  a fluorine atom is more preferable.  As the repeating unit (A), any repeating unit is useful so far  as it is a repeating unit having an ionic structural site and  capable of decomposing upon irradiation with an actinic ray  or radiation to generate acid, wherein the ionic structural site  is a structure capable of generating an acid anion in a side  chain of the resin upon irradiation with an actinic ray or  radiation.  As the alkyl group contained in the alkoxycarbonyl group,  the same alkyl groups as those in the foregoing R$_{04 }$to R$_{0}$s and  R$_{07 }$to R$_{09 }$are preferable.  As the repeating unit (A), for example, repeating units  represented by any one of the following general formulae (III)  to (V) are preferable.  Examples of the alkyl group represented by R$_{2}$s to R$_{27 }$and  R$_{33 }$ which is preferable include an optionally substituted  alkyl group having not more than 20 carbon atoms, for  example, a methyl group, an ethyl group, a propyl group, an  isopropyl group, an n-butyl group, a sec-butyl group, a hexyl  group, a 2-ethylhexyl group, an octyl group and a dodecyl  group. Of these, an alkyl groups having not more than 8  carbon atoms is more preferable.  Examples of the cycloalkyl group include a cycloalkyl  group which may be of a monocyclic type or a polycyclic  type. Of these, an optionally substituted cycloalkyl group of a  monocyclic type having from  3  to 8 carbon atoms, for  example, a cyclopropyl group, a cyclopentyl group and a  cyclohexyl group, is preferable.  Examples of the alkenyl group which is preferable include  an optionally substituted alkenyl group having from 2 to  6  carbon atoms, for example, a vinyl group, a propenyl group,  an ally! group, a butenyl group, a pentenyl group, a hexenyl  group and a cyclohexenyl group.  Examples of the aryl group which is preferable include an  optionally monocyclic or polycyclic aromatic group having  from  6  to 14 carbon atoms. Specific examples thereofinclude  a phenyl group, a tolyl group, a chlorophenyl group, a meth› oxypheny  I  group and a naphthy  I  group. Also, ary  I  groups may  be bonded to each other to form a multi-ring.  (III)  (IV)  Ros  Ro1  I  I  *---f-C-Ct-*  I  I  Ro6 X2  I  A  (V)  Examples of the aralkyl group include an optionally sub› stituted aralkyl group having from  7  to 15 carbon atoms, for  example, a benzyl group, a phenethyl group and a cumyl  group.  In the foregoing general formulae (III) to (V), each ofR$_{04}$,  Ros and R$_{07 }$to R$_{09 }$independently represents a hydrogen atom,  an alkyl group, a cycloalkyl group, a halogen atom, a cyano  group or an alkoxycarbonyl group;  As the ring formed through bonding ofR$_{26 }$and R$_{27 }$to each  other together with a nitrogen atom, those of forming a  5-membered to 8-membered ring are preferable. Specific  examples thereof include pyrrolidine, piperidine and pipera› zme.  As the arylene group represented by X$_{1 }$ to X$_{3}$ , optionally  substituted arylene groups having from 6 to 14 carbon atoms  are preferable. Specific examples thereof include a phenylene  group, a tolylene group and a naphthylene group.  Examples of the alkylene group which is preferable  include an alkylene group having from 1 to 8 carbon atoms,  for example, a methylene group, an ethylene group, a propy› lene group, a butylene group, a hexylene group and an octy› lene group.  each ofX$_{1 }$to X$_{3 }$independently represents a single bond, an  arylene group, an alkylene group, a cycloalkylene group,  -0-,  -SO$_{2}$ -,  -CO-, -N(R$_{33}$)-or a divalent linking  group composed of a combination thereof;  R$_{2}$s represents an alkyl group, a cycloalkyl group, an alk› enyl group, an aryl group or an aralkyl group;  each ofR$_{26}$ , R $_{27 }$and R$_{33 }$independently represents a hydro› gen atom, an alkyl group, a cycloalkyl group, an alkenyl  group, an aryl group or an aralkyl group; and 