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[0097] In general formula. (a0-1), R $^{2 }$represents a divalent hydrocarbon group which may have a substituent. 2 

[0098] With respect to R , the hydrocarbon group "has a substituent" means that part or all of the hydrogen atoms within the hydrocarbon group has been substituted with a group or an atom other than a hydrogen atom. 

[0099] The hydrocarbon group may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An "aliphatic hydrocarbon group" refers to a hydrocarbon group that has no aromaticity. 

[0100] The aliphatic hydrocarbon group may be saturated or unsaturated. In general, the aliphatic hydrocarbon group is preferably saturated, 

[0101] As specific examples of the aliphatic hydrocarbon group, a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the struc› ture thereof can be given. 

[0102] The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 or 2. 

[0103] As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, Specific examples thereof include a methylene group [----CH$_{2}$-], an ethylene group [-(CH$_{2}$ ) 2 -], a trimethylene group [-(CH$_{2}$k], a tetrameth› ylene group [-(CH$_{2}$ ) 4 -] and a pentamethylene group [-( CH$_{2}$ )s-]. Among these, a methylene group or an ethylene group is preferable. 

[0104] As the branched aliphatic hydrocarbon group, branched alkylene groups are preferred, and specific examples include various alkylalkylene groups, including alkylmethylene groups such as -CH(CH$_{3}$)-, --CH (CH$_{2}$CH$_{3}$ )-, ----C(CH$_{3}$ ) 2 -, ----C(CH$_{3}$)(CH$_{2}$CH$_{3}$ )-, -C(CH$_{3}$)(CH$_{2}$CH$_{2}$CH$_{3}$ )-, and -C(CH$_{2}$CH$_{3}$ ) 2 -; alkyl› ethylene groups such as ----CH(CH$_{3}$)CH$_{2}$ -, -CH(CH$_{3}$)CH (CH$_{3}$ )-, -C(CH$_{3}$ ) $_{2}$CH$_{2}$ -, -CH(CH$_{2}$CH$_{3}$)CH$_{2}$ -, and -C(CH$_{2}$CH$_{3}$ ) $_{2}$----CH$_{2}$ -; alkyltrimethylene groups such as -CH(CH$_{3}$)CH$_{2}$CH$_{2}$ -, and ----CH$_{2}$CH(CH$_{3}$)CH$_{2}$ -; and alkyltetramethylene groups such as -CH(CH$_{3}$) CH$_{2}$CH$_{2}$CH$_{2}$ -, and -CH$_{2}$CH(CH$_{3}$)CH$_{2}$CH$_{2}$ -. As the alkyl group within the alkylalkylene group, a linear alkyl group of 1 to 5 carbon atoms is preferable. 

[0105] The linearor branched aliphatic hydrocarbon group (chain-like aliphatic hydrocarbon group) may or may not have a substituent. Examples of substituents include a fluo› rine atom, a fluorinated alkyl group of 1 to 5 carbon atoms, and an oxygen atom (=0). 

[0106] As examples of the hydrocarbon group containing a ring in the structure thereof, a cyclic aliphatic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the terminal of the aforementioned chain-like aliphatic hydrocar› bon group, and a group in which the cyclic aliphatic hydro› carbon group is interposed within the aforementioned chain› like aliphatic hydrocarbon group, can be given. 

[0107] The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. 

[0108] The cyclic aliphatic hydrocarbon group may be either a polycyclic group or a monocyclic group. 

[0109] As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane of3 to 6 carbon atoms is preferable. Examples of the mono› cycloalkane include cyclopentane and cyclohexane. 

[0110] As the polycyclic group, a group in which two hydrogen atoms have been removed from a polycycloalkane of7 to 12 carbon atoms is preferable. Examples of the poly› cycloalkane include adamantane, norbomane, isobomane, tricyclodecane and tetracyclododecane. 

[0111] The cyclic aliphatic hydrocarbon group may or may not have a substituent. 

[0112] Examples of the substituent include an alkyl group of 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group of 1 to 5 carbon atoms, and an oxygen atom (=0). 

[0113] Examples of the aforementioned aromatic hydro› carbon group include a divalent aromatic hydrocarbon group in which one hydrogen atom has been removed from a ben› zene ring of a monovalent aromatic hydrocarbon group such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group or a phenanthryl group; an aromatic hydrocarbon group in which part of the carbon atoms constituting the ring of the aforementioned divalent aromatic hydrocarbon group has been substituted with a het› ero atom such as an oxygen atom, a sulfur atom or a nitrogen atom; and an aromatic hydrocarbon group in which one hydrogen atom has been removed from a benzene ring of an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group or a 2-naphthylethyl group. 

[0114] The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group of 1 to 5 carbon atoms, a fluorine atom, a fluori› nated alkyl group of 1 to 5 carbon atoms, and an oxygen atom (=0). 2 

[0115] Among the aforementioned examples, as R , an ali› phatic hydrocarbon group which may have a substituent is preferable, a linear or branched aliphatic hydrocarbon group is more preferable, a linear or branched alkylene group is still more preferable, and a linear alkylene group is particularly desirable. 

[0116] In the present invention, as the structural unit (a0), a structural unit represented by general formula (a0-1-10) shown below is particularly desirable. 

[Chemical Formula 9] 

<img src='content_image/934358.jpg'>

In general formula ( a0-1-10), R represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms; R la represents an aliphatic cyclic group-containing acid dissociable, dissolution inhibit› ing group; and A2c represents an alkylene group of 1 to 12 carbon atoms. 

[0117] In general formula ( a0-1-10), R represents a hydro› gen atom, an alkyl group of 1 to 5 carbon atoms or a haloge› nated alkyl group of 1 to 5 carbon atoms, and the same groups as those described above for R in general formula ( a0-1) can be used. 

[0118] In general formula (a0-1-10), R$^{1$_{a }$}$represents an ali› phatic cyclic group-containing acid dissociable, dissolution 

(a0-1-10) 

