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[0052] Preferred examples of the alkali-soluble group include a carboxyl group, a fluorinated alcohol group (pref› erably a hexafluoroisopropanol group), and a sulfonic acid group. 

[0053] The group which is preferable as the acid-decom› posable group is a group in which a hydrogen atom of the alkali-soluble group is substituted with a group capable of leaving by an acid. 

[0054] Examples of the group capable ofleaving by an acid include -C(R 36 )(R 37 )(R 38 ), ----C(R 36 )(R 37 )(OR 39 ), and -CCR01)CR02)(OR39)- 

[0055] In the formulae, R 36 to R 39 each independently rep› resent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R 36 and R 37 may be bonded to each other to form a ring. 

[0056] R 01 to R 02 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. 

[0057] The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group, or the like, and more preferably a tertiary alkyl ester group. 

[0058] Furthermore, a repeating unit represented by the following General Formula (AI) is preferable as the repeating unit having an acid-decomposable group, which can be con› tained in the resin (A). 

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[0059] In General Formula (AI), 

[0060] Xa 1 represents a hydrogen atom, or an alkyl group which may have a substituent, 

[0061] T represents a single bond or a divalent linking group, 

[0062] Rx 1 to Rx 3 each independently represent an (linear or branched) alkyl group or a (monocyclic or polycyclic) cycloalkyl group, and 

[0063] two members out of Rx 1 to Rx 3 may be bonded to each other to form a (monocyclic or polycyclic) cycloalkyl group. 

[0064] Examples of the alkyl group which may have a substituent, represented by Xa 1 , include a methyl group or a group represented by ----CH 2 -R$_{11}$. R$_{11 }$represents a halogen atom (a fluorine atom or the like), a hydroxyl group, or a monovalent organic group, and examples thereof include an alkyl group having 5 or less carbon atoms, and an acyl group having 5 or less carbon atoms, preferably an alkyl group having 3 or less carbon atoms, and more preferably a methyl group. In one aspect, Xa 1 is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, a hydroxymethyl group, or the like. 

[0065] Examples of the divalent linking group ofT include an alky lene group, a -COO-Rt- group, and an ---0 Rt- group. In the formulae, Rt represents an alkylene group or a cycloalkylene group. 

(Al) 

[0066] Tis preferably a single bond or a-COO-Rt- group. Rtis preferably analkylene group having 1 to 5 carbon atoms, and more preferably a ----CH 2 - group, a -(CH 2 ) 2 - group, or a -(CH 2 ) 3 - group. 

[0067] As the alkyl group of Rx 1 to Rx 3 , an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and at-butyl group is preferable. 

[0068] As the cycloalkyl group ofRx 1 to Rx 3 , a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclo› hexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracy› clododecanyl group, and an adamantyl group are preferable. 

[0069] As the cycloalkyl group formed by the mutual bond› ing of two members ofRx 1 to Rx 3 , a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable, and a monocyclic cycloalkyl group having 5 or 6 carbon atoms is particularly preferable. 

[0070] In the cycloalkyl group formed by the mutual bond› ing of two members ofRx 1 to Rx 3 , for example, one of the methylene groups constituting the ring may be substituted with a hetero atom such as an oxygen atom, or with a group having a hetero atom, such as a carbonyl group. 

[0071] An aspect of the repeating unit represented by Gen› eral Formula (AI), for example, in which Rx 1 is a methyl group or an ethyl group, and Rx 2 and Rx 3 are bonded to each other to form the afore-mentioned cycloalkyl group, is pref› erable. 

[0072] Each of the groups may have a substituent, and examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms), with those having 8 or less carbon atoms being preferable. 

[0073] The total content of the repeating unit having an acid-decomposable group is preferably 20% by mole to 90% by mole, more preferably 25% by mole to 85% by mole, and still more preferably 30% by mole to 80% by mole, with respect to all the repeating units in the resin (A). 

[0074] Specific preferred examples of the repeating unit having an acid-decomposable group are set forth below, but the present invention is not limited thereto. 

[0075] In the specific examples, Rx and Xa 1 each represent a hydrogen atom, CH 3 , CF 3 , or CH 2 OH. Rxa and Rxb each represent a an alkyl group having 1 to 4 carbon atoms. Z represents a substituent containing a polar group, and in the case where Z’s are present in plural numbers, they are each independent. p represents O or a positive integer. Examples of the substituent containing a polar group, represented by Z, include a linear or branched alkyl group, and a cycloalkyl group, each having a hydroxyl group, a cyano group, an amino group, an alkylamide group, or a sulfonamide group, and preferably an alkyl group having a hydroxyl group.As the branched alkyl group, an isopropyl group is particularly pref› erable. 

