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a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbomyl group, and an adamantyl group. 

[0070] Examples of the aromatic hydrocarbon group hav› ing 6 to 20 carbon atoms include a phenyl group. 

[0071] Examples of the hydrocarbon group having 2 to 20 carbon atoms in total, which has any one selected from the group consisting of -0-, -S-, --CO-, -SO$_{2}$ -, and -NRa- or a group obtained by combining a plurality of these include a group in which ----CH$_{2}$ - in the alkyl group having 2 to 20 carbon atoms is substituted with any one selected from the group consisting of -0-, -S-, -CO-, -SO$_{2}$ -, and -NRa- or a group obtained by combining a plurality of these. Among these, a group in which -CH$_{2}$ - in the alkyl group having 2 to 20 carbon atoms is substituted with any one selected from the group consisting of ---0-, --CO-, -OCO-, and -COO- is preferable, and an alkoxyalkyl group having 2 to 20 carbon atoms, an acylalkyl group having 2 to 20 carbon atoms, or an alkyloxycarbonylalkyl group having 3 to 20 carbon atoms is more preferable. 

[0072] The alkoxyalkyl group having 2 to 20 carbon atoms is preferably an alkoxyalkyl group having 2 to 10 carbon atoms, and examples thereof include a methoxyethyl group. 

[0073] The acylalkyl group having 2 to 20 carbon atoms is preferably an acylalkyl group having 2 to 10 carbon atoms, and examples thereof include an acetylmethyl group and an acetylethyl group. 

[0074] The alkyloxycarbonylalkyl group having 3 to 20 carbon atoms is preferably an alkyloxycarbonylalkyl group having 3 to 10 carbon atoms, and examples thereof include a methoxycarbonylmethyl group. 

[0075] Among the aforementioned groups, the organic group having 2 or more carbon atoms which is represented by R 2 is preferably a hydrocarbon group having 2 to 20 carbon atoms which may include a hetero atom, more preferably an alkyl group having 2 to 20 carbon atoms or an alkyl group having 2 to 20 carbon atoms in total in which -CH$_{2}$ - is substituted with any one selected from the group consisting of -0-, --CO-, ---OCO-, and --COO-, even more preferably an alkyl group having 2 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms, an acylalkyl group having 2 to 20 carbon atoms, or an alky› loxycarbonylalkyl group having 3 to 20 carbon atoms, and particularly preferably an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, an acylalkyl group having 2 to 10 carbon atoms, or an alky› loxycarbonylalkyl group having 3 to 10 carbon atoms. 

[0076] Among these, the alkyl group having 2 to 20 carbon atoms as the organic group having 2 or more carbon atoms which is represented by R 2 is preferably an alkyl group having 3 to 10 carbon atoms, and more preferably an alkyl group represented by *----CH$_{2}$-X. X represents a cycloalkyl group having 3 to 9 carbon atoms or a linear alkyl group having 2 to 9 carbon atoms and preferably represents a cycloalkyl group having 3 to 9 carbon atoms. * represents a bonding position. 

[0077] Examples of the monovalent organic group includ› ing a fluorine atom represented by Rf include a linear or 

branched alkyl group having 1 to 10 carbon atoms in which a portion or all of hydrogen atoms are substituted with a fluorine atom or a fluoroalkyl group. Specific examples thereof include CF$_{3}$, C$_{2}$F$_{5}$ , C$_{3}$F$_{7}$ , C$_{4}$ F$_{9}$, C$_{5}$F w C$_{6}$F $_{13}$, C$_{7}$F $_{15}$, C$_{8}$F$_{17}$, CH$_{2}$CF$_{3}$ , CH$_{2}$CH$_{2}$CF$_{3}$, CH$_{2}$C$_{2}$F$_{5}$, CH$_{2}$CH$_{2}$C$_{2}$F$_{5}$ , CH$_{2}$C$_{3}$F$_{7}$ , CH$_{2}$CH$_{2}$C$_{3}$F$_{7}$ , CH$_{2}$C$_{4}$ F$_{9}$ , and CH$_{2}$CH$_{2}$C$_{4}$F$_{9}$ . 

[0078] Rf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms, more preferably a fluorine atom or CF $_{3}$ , and even more preferably a fluorine atom. 

[0079] The divalent electron withdrawing group repre› sented by X is not particularly limited, but examples thereof include -CO-, -CON(Rb)-, --COO-, ----C( NRb)-, -SO-, and -SO$_{2}$ -. In the specific examples exemplified as the divalent electron withdrawing group, a bonding position thereof is not particularly limited. In Formula (I), in a case where X is --COO-, a bond formed by X and R 1 may be -OCO-R 1 or may be ----COO-R 1 . That is, the carbonyl carbon of ---OCO- may be bonded to R $^{1 }$and the ether oxygen of --COO- may be bonded to R 1 . 

[0080] Rb represents a hydrogen atom or a hydrocarbon group (preferably an alkyl group having 1 to 5 carbon atoms) having 1 to 20 carbon atoms. 

[0081] In view of acidity of the acid represented by Formula (I), X is preferably -CO- or -COO-. 

[0082] In a case where X represents ----CON(Rb)-, Rb and R 1 may be linked to each other to form a ring. 

[0083] n represents O or 1. In view of acidity of the acid represented by Formula (I), it is preferable that n represents 1. 

[0084] Examples of the suitable aspect of the acid repre› sented by Formula (I) include an aspect in which R 1 s a linear or branched alkyl group, R 2 may be a hydrocarbon group having 2 to 20 carbon atoms which may include a hetero atom, Rf is a fluorine atom, and n is 1. Among these, an aspect in which R 1 is a linear or branched alkyl group having 1 to 5 carbon atoms, R $^{2 }$is an alkyl group having 3 to 10 carbon atoms, Rf is a fluorine atom, and n is 1 is preferable. 

[0085] One of the specific examples of the acid repre› sented by Formula (I) is provided below. 

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