67  US 9,323,150 B2  68  -continued  The resin (Aa) according to the present invention can fur› ther contain a repeating unit having a cyclic hydrocarbon  structure in which no polar group is introduced and exhibiting  no acid-decomposability. As such a repeating unit, there can  be mentioned any of the repeating units of general formula  (VII) below.  In general formula (VII), Rs represents a hydrocarbon  group having at least one cyclic hydrocarbon structure in  which no polar group (for example, a hydroxyl group or a  cyano group) is introduced.  Ra represents a hydrogen atom, an alkyl group or a group of  the formula-CH$_{2}$-O-Ra$_{2}$ .  In this formula, Ra$_{2 }$represents  a hydrogen atom, an alkyl group or an acyl group. Ra is  preferably a hydrogen atom, a methyl group, a hydroxyalkyl 40  group or a trifluoromethyl group, most preferably a hydrogen  atom or a methyl group.  The cyclic hydrocarbon structures introduced in Rs include  a monocyclic hydrocarbon group and a polycyclic hydrocar- bon group. The monocyclic hydrocarbon group is preferably  a monocyclic hydrocarbon group having 3 to 7 carbon atoms,  more preferably a cyclopentyl group or a cyclohexyl group.  The polycyclic hydrocarbon groups include a ring-assem› bly hydrocarbon group and a crosslinked-ring hydrocarbon  group. As preferred crosslinked-ring hydrocarbon rings, there  can be mentioned a norbornyl group, an adamantyl group, a  bicyclooctanyl group, a tricyclo[5.2.l .0 2 • $^{6}$]decanyl group and  the like. As more preferred crosslinked-ring hydrocarbon  rings, there can be mentioned a norbornyl group and an ada› mantyl group.  Substituents may be introduced in these cyclohydrocarbon  groups. As preferred substituents, there can be mentioned a  halogen atom (bromine, chlorine or fluorine atom) and an  alkyl group (methyl, ethyl, butyl or t-butyl group). A further  substituent may be introduced in this alkyl group. As the  optional further substituent, there can be mentioned a halogen  atom, an alkyl group, a hydroxyl group with its hydrogen  atom replaced or an amino group with its hydrogen atom  replaced.  As a substituent for the replacement of the hydrogen atom,  there can be mentioned, for example, an alkyl group, a  monovalent aliphatic hydrocarbon ring group, an aralkyl  group, a substituted methyl group, a substituted ethyl group,  an acyl group, an alkoxycarbonyl group or an aralkyloxycar› bonyl group. Preferred alkyl groups include alkyl groups each  having  1  to  4  carbon atoms. Preferred substituted methyl  groups include methoxymethyl, methoxythiomethyl, benzy› loxymethyl, t-butoxymethyl and 2-methoxyethoxymethyl  groups. Preferred substituted ethyl groups include 1-ethoxy› ethyl and l-methyl-1-methoxyethyl groups. Preferred acyl  groups include aliphatic acyl groups having  1  to 6 carbon  atoms, such as formyl, acetyl, propionyl, butyryl, isobutyryl,  valeryl and pivaloyl groups. Preferredalkoxycarbonyl groups  include alkoxycarbonyl groups each having  1  to  4  carbon  atoms and the like. It is optional for the resin (Aa) to contain  the repeating unit with a cyclohydrocarbon structure contain› ing no polar group, which repeating unit does not exhibit any  acid decomposability. When the repeating unit is contained,  the content thereof is preferably in the range of  1  to  40  mo!%,  more preferably 5 to 20 mo! %, based on all the repeating  units of the resin (Aa).  Particular examples of the repeating units with a cyclohy- drocarbon structure containing no polar group, which repeat› ing units do not exhibit any acid decomposability are shown  below. The examples in no way limit the scope of the present  invention. In the formulae, Ra represents H, CH$_{3}$ ,  CH$_{2}$OH or  CF3.  Ra  Ra  j:j:  6 CO  j: j:  Ra  Ra  j: j:  ¢  OH  OH  (VII) 