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polarity of the entire component (Al) is increased. When the polarity of the component (Al) is increased, the solubility in a developing solution is changed relatively. For example, when the developing solution is an alkali developing solution, the solubility of the component (Al) in the developing solu- tion is increased. On the other hand, when the developing solution is an organic developing solution, the solubility of the component (Al) in the developing solution is decreased. 

The acid dissociable group is not particularly limited, and any of the groups that have been conventionally proposed as acid dissociable groups for the base resins of chemically amplified resists can be used. Generally, groups that form either a cyclic or chain-like tertiary alkyl ester with the car› boxyl group of the (meth)acrylic acid, and acetal-type acid dissociable groups such as alkoxyalkyl groups are widely known. 

Here, a tertiary alkyl ester describes a structure in which an ester is formed by substituting the hydrogen atom of a car› boxyl group with a chain-like or cyclic tertiary alkyl group, and a tertiary carbon atom within the chain-like or cyclic tertiary alkyl group is bonded to the oxygen atom at the terminal of the carbonyloxy group (-C(=0)-0-). In this tertiary alkyl ester, the action of acid causes cleavage of the bond between the oxygen atom and the tertiary carbon atom, thereby forming a carboxy group. 

The chain-like or cyclic alkyl group may have a substitu› ent. 

Hereafter, for the sake of simplicity, groups that exhibit acid dissociability as a result of the formation of a tertiary alkyl ester with a carboxyl group are referred to as "tertiary alkyl ester-type acid dissociable groups". 

Examples of tertiary alkyl ester-type acid dissociable groups include aliphatic branched, acid dissociable groups and aliphatic cyclic group-containing acid dissociable groups. 

The term "aliphatic branched" refers to a branched struc› ture having no aromaticity. The "aliphatic branched, acid dissociable group" is not limited to be constituted of only carbon atoms and hydrogen atoms (not limited to hydrocar- bon groups), but is preferably a hydrocarbon group. Further, the "hydrocarbon group" may be either saturated or unsatur› ated, but is preferably saturated. 

As an example of the aliphatic branched, acid dissociable group, for example, a group represented by the formula -C(R$^{71}$)(R$^{72}$)(R 73 ) can be given. In the formula, each ofR 7 to R$^{73 }$independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by the formula -C(R$^{71 }$)(R$^{72}$)(R 73 ) preferably has 4 to 8 carbon atoms, and specific examples include a tert-butyl group, a 2-methyl-2- butyl group, a 2-methyl-2-pentyl group and a 3-methyl-3- pentyl group. 

Among these, a tert-butyl group is particularly desirable. 

The term "aliphatic cyclic group" refers to a monocyclic group or polycyclic group that has no aromaticity. 

In the "aliphatic cyclic group-containing acid dissociable group", the "aliphatic cyclic group" may or may not have a substituent. Examples of the substituent include an alkyl group ofl to 5 carbon atoms, an alkoxy group ofl to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group of 1 to 5 60 carbon atoms, and an oxygen atom (=0). 

The basic ring of the "aliphatic cyclic group" exclusive of substituents is not limited to be constituted from only carbon atom and hydrogen atom (not limited to hydrocarbon groups), but is preferably a hydrocarbon group. Further, the "hydro- carbon group" may be either saturated or unsaturated, but is preferably saturated. 

The aliphatic cyclic group may be either a monocyclic group or a polycyclic group. 

As such aliphatic cyclic groups, groups in which one or more hydrogen atoms have been removed from a monocy› cloalkane or a polycycloalkane such as a bicycloalkane, tri› cycloalkane or tetracycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group, may be used. Specific examples of aliphatic cyclic hydrocarbon groups include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; and groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, nor› bornane, isobomane, tricyclodecane or tetracyclododecane. In these aliphatic cyclic hydrocarbon groups, part of the car- bon atoms constituting the ring may be replaced with an ethereal oxygen atom (---0-). 

Examples of aliphatic cyclic group-containing acid disso- ciable groups include 

(i) a monovalent aliphatic cyclic group in which a substitu› ent (a group or an atom other than hydrogen) is bonded to the carbon atom on the ring skeleton to which an atom adjacent to the acid dissociable group ( e.g., "---0-" within "----C (=0)-0- group") is bonded to form a tertiary carbon atom; and 

(ii) a group which has a branched alkylene group contain› ing a tertiary carbon atom, and a monovalent aliphatic cyclic group to which the tertiary carbon atom is bonded. 

In the group (i), as the substituent bonded to the carbon atom to which an atom adjacent to the acid dissociable group on the ring skeleton of the aliphatic cyclic group is bonded, an alkyl group can be mentioned. Examples of the alkyl group include the same groups as those represented by R $^{14 }$in for- mulas (1-1) to (1-9) described later. 

Specific examples of the group (i) include groups repre› sented by general formulas (1-1) to (1-9) shown below. 

Specific examples of the group (ii) include groups repre› sented by general formulas (2-1) to (2-6) shown below. 

[Chemical Formula 3] 

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