[0037] As the alkyl group as a substituent at the a-posi› tion, a linear or branched alkyl group is preferable, and specific examples thereof include alkyl groups of 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an iso› pentyl group, and a neopentyl group. 

[0038] Specific examples of the halogenated alkyl group as the substituent at the a-position include groups in which some or all hydrogen atoms of the above-described "alkyl group as the substituent at the a-position" are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable. 

[0039] Specific examples of the hydroxyalkyl group as the substituent at the a-position include groups in which some or all hydrogen atoms of the above-described "alkyl group as the substituent at the a-position" are substituted with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1. 

[0040] In the present specification and the scope of the present patent claims, asymmetric carbons may be present or enantiomers or diastereomers may be present depending on the structures of the chemical formulae. In this case, these isomers are represented by one formula. These isomers may be used alone or in the form of a mixture. 

[0041] (Resist Composition) 

[0042] The resist composition according to the present embodiment is a resist composition which generates an acid upon exposure and whose solubility in a developing solution is changed due to an action of the acid. 

[0043] Such a resist composition contains a base material component (A) in which the solubility in a developing solution is changed due to an action of the acid (hereinafter, also referred to as "component (A)"). 

[0044] In a case where a resist film is formed using the resist composition according to the present embodiment and the formed resist film is subjected to a selective exposure, acid is generated at exposed portions of the resist film, and the generated acid acts on the component (A) to change the solubility of the component (A) in a developing solution, whereas the solubility of the component (A) in a developing solution is not changed at unexposed portions of the resist film, thereby generating difference in solubility in a devel› oping solution between exposed portions and unexposed portions of the resist film. Therefore, by subjecting the resist film to development, the exposed portions of the resist film are dissolved and removed to form a positive type resist pattern in a case of a positive type resist, whereas the unexposed portions of the resist film are dissolved and removed to form a negative type resist pattern in a case of a negative type resist. 

[0045] In the present specification, a resist composition which forms a positive type resist pattern by dissolving and removing the exposed portions of the resist film is called a positive type resist composition, and a resist composition which forms a negative type resist pattern by dissolving and removing the unexposed portions of the resist film is called a negative type resist composition. 

[0046] The resist composition of the present embodiment may be a positive type resist composition or a negative type resist composition. 

[0047] Further, in the formation of a resist pattern, the resist composition of the present embodiment can be applied to an alkali developing process using an alkali developing solution in the developing treatment, or a solvent developing process using a developing solution containing an organic solvent (organic developing solution) in the developing treatment. 

[0048] In other words, the resist composition of the pres› ent embodiment is a "positive type resist composition for an alkali developing process" that forms a positive type resist pattern in an alkali developing process and is a "negative type resist composition for a solvent developing process" that forms a negative type resist pattern in a solvent devel› oping process. 

[0049] The resist composition of the present embodiment has a function of generating acid upon exposure, and in the resist composition, the component (A) may generate an acid upon exposure, or an additive component other than the component (A) may generate an acid upon exposure. 

[0050] In the present embodiment, the resist composition may be a resist composition (1) containing an acid generator component (B) which generates acid upon exposure (here› inafter, referred to as "component (B)"); a resist composition (2) in which the component (A) is a component which generates acid upon exposure; or a resist composition (3) in which the component (A) is a component which generates acid upon exposure, and further containing an acid generator component (B). 

[0051] That is, in a case where the resist composition of the present invention is the above-described resist compo› sition (2) or (3), the component (A) is a "base material component which generates acid upon exposure and whose solubility in a developing solution is changed due to an action of an acid". In a case where the component (A) is a base material component which generates an acid upon exposure and whose solubility in a developing solution is changed due to an action of an acid, the component (Al) described below is preferably a polymeric compound which generates an acid upon exposure and whose solubility in a developing solution is changed due to an action of an acid. As the polymeric compound, a copolymer having a consti› tutional unit which generates acid upon exposure can be used. 

[0052] As the constitutional unit which generates acid upon exposure, a known constitutional unit can be used. 

[0053] It is particularly preferable that the resist compo› sition of the present embodiment corresponds to the case of (1) described above. 

[0054] <Component (A)> 

[0055] The component (A) is a base material component whose solubility in a developing solution is changed due to an action of an acid. 

[0056] In the present invention, the term "base material component" indicates an organic compound capable of forming a film, and is preferably an organic compound having a molecular weight of 500 or greater. In a case where the organic compound has a molecular weight of 500 or greater, the film-forming ability is improved, and a resist pattern at a nano level can be easily formed. 

[0057] The organic compound used as the base material component is broadly classified into non-polymers and polymers. 

[0058] In general, as a non-polymer, any of those which have a molecular weight in the range of 500 to less than 

