content_image/938923.jpg
blended with the resist composition, or may be included in a component other than the component (A). 

In the resist composition, the anion moiety of the partial structure represented by the general formula (a0-r-1) becomes an appropriate weakly acidic anion upon exposure to exhibit a quenching (acid diffusion control) effect to thus trap the acid generated upon exposure. In the formation of a resist pattern, in exposed areas of a resist film, the partial structure is decomposed upon exposure to lose acid diffusion controlling properties (basicity), and thus the quenching effect is not exhibited. In unexposed areas of the resist film, the partial structure exhibits the quenching effect. 

[Chemical formula 2] 

<img src='content_image/938923.jpg'>

In the formula, Y$^{1 }$represents a divalent linking group; each ofR$^{2 }$and R$^{3 }$independently represents a group having Oto 20 carbon atoms, which is not a fluorine atom, and either R $^{2 }$or R 3 may form a ring with Y 1 ; m represents an integer of 1 or more; and Mm+ represents an m-valent organic cation. 1 

In the formula (a0-r-1), Y represents a divalent linking group. 1 

Preferred examples of the divalent linking group in Y include an optionally substituted divalent hydrocarbon group and a hetero atom-containing divalent linking group. Optionally Substituted Divalent Hydrocarbon Group: 1 

When Y represents an optionally substituted divalent hydrocarbon group, the hydrocarbon group may be an ali› phatic hydrocarbon group or an aromatic hydrocarbon group. Aliphatic Hydrocarbon Group in Y 1 

The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be either saturated or unsaturated, and in general, it is preferably saturated. 

Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and an ali› phatic hydrocarbon group containing a ring in a structure thereof. 

## Linear or Branched Aliphatic Hydrocarbon Group 

The linear or branched aliphatic hydrocarbon group pref› erably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon 50 atoms, still more preferably 1 to 5 carbon atoms, and most preferably 1 to 3 carbon atoms. 

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, examples thereof include a methylene group [-CH$_{2}$ -], an ethylene group 55 [-(CH$_{2}$ ) 2 -], r a trimethylene group [-(CH 2 ) 3 -], a tet› ramethylene group [-(CH$_{2}$ ) 4 -], and a pentamethylene group [-(CH$_{2}$ ) 5 -]. 

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically, examples thereof include 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 -; alkylethylene 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 

(a0-r-1) 

----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 in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable. 

The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, which is substituted with a fluorine atom, an alkoxy group having 1 to 10 carbon atoms, an alkoxyalkyl group having 2 to 15 carbon atoms, and a carbonyl group. 

## Aliphatic Hydrocarbon Group Containing Ring in Structure Thereof 

Examples of the aliphatic hydrocarbon group containing a ring in a structure thereof include an optionally substituted cyclic aliphatic hydrocarbon group containing a hetero atom in a ring structure thereof (a group in which two hydrogen atoms are eliminated from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the terminal of a linear or branched aliphatic hydro› carbon group, and a group in which the cyclic aliphatic hydro› carbon group intervenes on the way of a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include the same groups as those described above. 

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

The cyclic aliphatic hydrocarbon group may be either a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms are eliminated from a monocycloalkane. The monocycloalkane is preferably one having 3 to 6 carbon atoms. Specifically, examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms are elimi› nated from a polycycloalkane. The polycycloalkane prefer› ably has 7 to 12 carbon atoms. Specifically, examples thereof include adamantane, norbornane, isobomane, tricyclode› cane, tetracyclododecane, and tricyclotetradecane. 

The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and a carbonyl group. 

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. 

The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. 

Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferable. 

Examples of the halogenated alkyl group as the substituent include a group in which some or all the hydrogen atoms of the above-described alkyl group are substituted with the above-described halogen atom. 

In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure thereof may be substituted with a substituent containing a hetero atom. The substituent containing a hetero atom is preferably ---0-, ----C(=O)---0-, -S-, -S(=O)$_{2}$-, or -S(=O) 2 - 0-. 

