JP5906076B2 - Resist pattern forming method - Google Patents

Description

  The present invention relates to a resist pattern forming method and a resist composition used therefor.

A technique (pattern formation technique) for forming a fine pattern on a substrate and processing the lower layer of the pattern by performing etching using the fine pattern as a mask is widely adopted in the manufacture of semiconductor elements and liquid crystal display elements. The fine pattern is usually made of an organic material, and is formed by a technique such as a lithography method or a nanoimprint method. For example, in a lithography method, a resist film is formed on a support such as a substrate using a resist material containing a base material component such as a resin, and the resist film is selected by radiation such as light or an electron beam. A step of forming a resist pattern having a predetermined shape on the resist film is performed by performing a general exposure and developing. And a semiconductor element etc. are manufactured through the process of processing a board | substrate by an etching using the said resist pattern as a mask.
The resist material is classified into a positive type and a negative type. A resist material whose solubility in an exposed portion of a developer is increased is called a positive type, and a resist material whose solubility in an exposed portion of a developer is reduced is called a negative type. .
As the developer, an alkaline aqueous solution (alkali developer) such as a tetramethylammonium hydroxide (TMAH) aqueous solution is usually used. In addition, an organic solvent such as an aromatic solvent, an aliphatic hydrocarbon solvent, an ether solvent, a ketone solvent, an ester solvent, an amide solvent, or an alcohol solvent is also used as a developer (for example, (See Patent Documents 1 and 2).

In recent years, pattern miniaturization is rapidly progressing due to the advancement of lithography technology.
As a technique for miniaturization, the exposure light source is generally shortened in wavelength (increased energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. Further, studies have been made on EB (electron beam), EUV (extreme ultraviolet), X-rays, and the like having shorter wavelengths (higher energy) than these excimer lasers.
Along with the shortening of the wavelength of the exposure light source, the resist material is required to be improved in lithography characteristics such as sensitivity to the exposure light source and resolution capable of reproducing a pattern with a fine dimension. A chemically amplified resist is known as a resist material that satisfies such requirements.
As the chemically amplified resist, a composition containing a base material component whose solubility in a developing solution is changed by the action of an acid and an acid generator component that generates an acid upon exposure is generally used. For example, when the developer is an alkali developer (alkaline development process), a substrate component that has increased solubility in an alkali developer due to the action of an acid is used.
Conventionally, a resin (base resin) is mainly used as a base component of a chemically amplified resist composition. At present, as a base resin of a chemically amplified resist composition used in ArF excimer laser lithography and the like, it has a structural unit derived from (meth) acrylic acid ester in its main chain because of its excellent transparency near 193 nm. Resin (acrylic resin) is the mainstream.
Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
The base resin generally contains a plurality of structural units in order to improve lithography properties and the like. For example, a structural unit having an acid-decomposable group that decomposes by the action of an acid generated from an acid generator to generate an alkali-soluble group, a structural unit having a lactone structure, a structural unit having a polar group such as a hydroxyl group, etc. are used. (For example, refer to Patent Document 3). When the base resin is an acrylic resin, as the acid-decomposable group, generally, a carboxy group in (meth) acrylic acid or the like is protected with an acid-dissociable group such as a tertiary alkyl group or an acetal group Is used.

As one of the methods for further improving the resolution, exposure (immersion exposure) is performed by interposing a liquid (immersion medium) having a higher refractive index than air between the objective lens of the exposure machine and the sample. A so-called immersion lithography (hereinafter referred to as “immersion exposure”) is known (for example, see Non-Patent Document 1).
According to immersion exposure, even when a light source having the same exposure wavelength is used, the same high resolution as when using a light source with a shorter wavelength or using a high NA lens can be achieved, and the depth of focus can be reduced. It is said that there is no decline. In addition, immersion exposure can be performed by applying an existing exposure apparatus. For this reason, immersion exposure is expected to be able to form resist patterns with low cost, high resolution, and excellent depth of focus. In particular, in terms of lithography characteristics such as resolution, the semiconductor industry is attracting a great deal of attention.
Immersion exposure is effective in forming all pattern shapes, and can be combined with super-resolution techniques such as the phase shift method and the modified illumination method that are currently being studied. Currently, as an immersion exposure technique, a technique mainly using an ArF excimer laser as a light source is being actively researched. Currently, water is mainly studied as an immersion medium.

One recently proposed lithography technique is a double patterning process in which a resist pattern is formed by performing patterning twice or more (see, for example, Non-Patent Documents 2 and 3). There are several methods for the double patterning process. For example, (1) a method of forming a pattern by repeating a lithography process (from application of a resist composition to exposure and development) and an etching process at least twice, and (2) lithography. There is a method of repeating the process twice or more. According to the double patterning process, a resist pattern having a higher resolution than that formed by a single lithography process (single patterning), whether using the same exposure wavelength light source or the same resist composition. Can be formed. The double patterning process can be performed using an existing exposure apparatus.
In addition, a double exposure method has been proposed in which after a resist film is formed, the resist film is exposed twice or more and developed to form a resist pattern (see, for example, Patent Document 4). According to this double exposure method, it is possible to form a high-resolution resist pattern as in the above-described double patterning process, and there is an advantage that the number of steps is small compared to double patterning.

  A positive development process that combines a positive chemically amplified resist composition, that is, a chemically amplified resist composition whose solubility in an alkali developer increases upon exposure, and an alkaline developer is a negative chemically amplified type. Compared to a negative development process in which a resist composition and an alkali developer are combined, there are advantages such as a simple photomask structure and excellent pattern characteristics. Therefore, at present, a positive development process in which a positive chemically amplified resist composition and an alkali developer are combined is mainly used for forming a fine resist pattern.

Japanese Patent Laid-Open No. 06-194847 JP 2009-025723 A JP 2003-241385 A JP 2010-040849 A

Proceedings of SPIE, 5754, 119-128 (2005). Proceedings of SPIE, 5256, 985-994 (2003). Proceedings of SPIE, 6153, 615301-1-19 (2006).

In recent years, with further progress in lithography technology and the expansion of application fields, various improvements in lithography properties have been made even in a positive development process that combines a positive chemically amplified resist composition and an alkaline developer. Desired.
When the positive development process is applied, when the resist film obtained by applying the chemically amplified resist composition on the support is selectively exposed, the exposed portion of the resist film is decomposed by acid in the base resin. Since the functional group is decomposed by the action of the acid generated from the acid generator and the like, and is changed from poorly soluble to soluble in an alkali developer, the unexposed portion of the resist film remains hardly soluble in alkali and remains unchanged. By developing with a developing solution, a dissolution contrast can be provided between the exposed and unexposed areas, and a positive resist pattern can be formed.
However, applying the positive development process to form finer patterns (isolated trench patterns, fine and dense contact hole patterns, etc.) A weak region is generated, and the resolution of the resist pattern is likely to deteriorate.

For the fine pattern formation as described above, a resist pattern (negative pattern) forming method in which a region having low optical intensity is selectively dissolved and removed is useful. As a method of forming a negative pattern using a chemically amplified resist composition used in the mainstream positive development process, a negative development process combined with a developer containing an organic solvent (organic developer) is used. Are known.
When the negative development process is applied, when the resist film obtained by applying the chemically amplified resist composition on the support is selectively exposed, the exposed portion of the resist film is decomposed by acid in the base resin. The functional group is decomposed by the action of an acid generated from an acid generator and the like, and it changes from being soluble to hardly soluble in an organic developer, while the unexposed portion of the resist film remains soluble and does not change. By developing with a developing solution, a dissolution contrast can be provided between the exposed and unexposed areas, and a negative resist pattern can be formed.
However, in the negative development process, it is difficult to sufficiently dissolve the exposed portion of the resist film by exposure.

On the other hand, there is a need for a new resist pattern forming method that can easily obtain a good dissolution contrast between an exposed portion and an unexposed portion of a resist film and can form a fine pattern.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the resist pattern formation method useful for forming a fine pattern, and the resist composition used for this.

  As a result of intensive studies, the present inventors have formed a resist film using a base resin having a structural unit having an acid-decomposable group so far, and undergoes a decomposition reaction of the acid-decomposable group. Instead of forming a resist pattern by the step, a resist film is formed by forming an association structure with an acidic group in the substrate component, and a salt between the association structure and an acid generated from the acid generator upon exposure. The inventors have found a method capable of forming a resist pattern by controlling the solubility of an exposed portion of a resist film in an organic developer by an exchange reaction, and have completed the present invention.

Specifically, a first aspect of the present invention, possess an acidic group, the base component containing no decomposing structure under the action of an acid (A), a compound capable of forming the acid group and association structure and (C) On the support, using a resist composition containing an acid generator component (B) having an acid dissociation constant (pKa) of less than 0 and an acid generator component (B) that generates an acid stronger than the acidic group by exposure. A step (1) of forming a resist film having an association structure of the acidic group and the compound (C), an acid generated from the acid generator component (B) by exposing the resist film, and the association structure Forming a new association structure with the compound (C), which has formed an acid, and exposing the acidic group; and developing the resist film using a developer containing an organic solvent. The exposed portion of the resist film is dissolved and removed to remove the positive resist pattern. A resist pattern forming method which comprises a step (3) to form a down.

In the present specification and claims, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The “alkylene group” includes linear, branched, and cyclic divalent saturated hydrocarbon groups unless otherwise specified.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with halogen atoms, and the “halogenated alkylene group” is the part of or all of the hydrogen atoms in the alkylene group is a halogen atom. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The “fluorinated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. The “fluorinated alkylene group” is a group in which part or all of the hydrogen atoms of the alkylene group are substituted with fluorine atoms.
The “hydroxyalkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a hydroxyl group.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

  ADVANTAGE OF THE INVENTION According to this invention, the resist pattern formation method useful for forming a fine pattern and the resist composition used for this can be provided.

It is a schematic process drawing explaining an example of one embodiment of a resist pattern formation method of the present invention in which a negative resist pattern is formed. It is a schematic diagram which shows the presence state of the (A)-(C) component in the resist film before and behind exposure about embodiment shown in FIG. It is a general | schematic process drawing explaining one example of embodiment of the resist pattern formation method of this invention in which a positive resist pattern is formed. It is a schematic diagram which shows the presence state of the (A)-(C) component in the resist film before and behind exposure about embodiment shown in FIG. It is a graph which shows the change of the resist film thickness at the time of changing the exposure amount in Example 1 and Comparative Example 1. It is a graph which shows the change of the resist film thickness at the time of changing the exposure amount in the comparative example 2. 10 is a graph showing changes in resist film thickness when the exposure amount is changed in Comparative Example 3. 6 is a graph showing changes in resist film thickness when the exposure amount is changed in Example 2. 12 is a graph showing changes in resist film thickness when the exposure amount is changed in Example 3.

≪Resist pattern formation method≫
The resist pattern formation method of the present invention comprises a base material component (A) having an acidic group (hereinafter also referred to as “component (A)”) and a compound (C) (hereinafter referred to as “( C) component ") and an acid generator component (B) (hereinafter also referred to as" component (B) ") that generates an acid having higher strength than the acidic group by exposure. A step (1) of forming a resist film having an association structure of the acidic group and the component (C) on the support; and exposing the resist film to generate an acid generated from the component (B); A step (2) of forming a new association structure with the component (C) that has formed the association structure to expose the acidic group, and a step of developing the resist film with a developer containing an organic solvent ( And a step (3) of developing using an organic developer.
When a resist composition containing the components (A) to (C) is applied on a support, an association structure (x) between the acidic group and the component (C) is formed, and a resist film is formed. When the resist film is selectively exposed, an acid is generated from the component (B) in the exposed portion of the resist film, and the acid (C) has formed the association structure (x) with the acid. ) And a new association structure (y) with the component is formed, and the acidic groups that have formed the association structure (x) are exposed, and the solubility of the resist film exposed portion in the organic developer changes. On the other hand, the solubility of the unexposed portion of the resist film in the organic developer does not change. This causes a difference in solubility in the organic developer between the exposed and unexposed portions of the resist film.
Therefore, in the resist pattern forming method of the present invention, when the resist composition is negative, the unexposed portion of the resist film is dissolved and removed to form a negative resist pattern; when the resist composition is positive The exposed portion of the resist film is dissolved and removed to form a positive resist pattern.

  In the present specification, a resist composition in which an unexposed portion of a resist film is dissolved and removed to form a negative resist pattern is referred to as a negative resist composition, and an exposed portion of the resist film is dissolved and removed to form a positive type. A resist composition for forming a resist pattern is referred to as a positive resist composition. The resist composition used in the step (1) may be a positive resist composition or a negative resist composition.

In the present invention, “can form an association structure with an acidic group” means that it can be a complex such as a salt by interacting with the acidic group.
“Form a new associating structure” means that the interacting partner is changed into another complex.

  Hereinafter, the resist pattern forming method of the present invention will be described with reference to the drawings. However, the present invention is not limited to this.

<First embodiment>
FIG. 1 shows an embodiment of a resist pattern forming method of the present invention in which a negative resist pattern is formed.
In the present embodiment, the base component having a carboxy group as the component (A), the alkylamine capable of forming an association structure with the carboxy group as the component (C), and the stronger than the carboxy group as the component (B) A resist composition (1) containing an acid generator that generates high acid upon exposure is used.
First, as shown in FIG. 1A, the resist composition (1) is applied onto a support 1 to form a film. When the resist composition (1) is applied onto the support 1, an association structure (x1) between an acidic group (carboxy group) in the base material component and the alkylamine is formed, and a resist film 2 is formed ( Step (1); FIG. 1 (a)).
Next, as shown in FIG. 1B, the resist film 2 formed as described above is exposed through a photomask 3 on which a predetermined pattern is formed (step (2); FIG. 1 (b)). .
By this exposure, acid is generated from the acid generator in the exposed region (exposed portion 2a) of the resist film 2. As a result, a new association structure (y1) is formed between the acid generated from the acid generator and the alkylamine forming the association structure (x1), and the association structure (x1) is formed. The exposed acidic group (carboxy group) is exposed. As a result, the solubility of the exposed portion 2a in the organic developer is reduced. On the other hand, the solubility of the unexposed portion 2b in the organic developer does not change or even if it changes, the amount of change is slight. As a result, a difference in dissolution rate (dissolution contrast) in the organic developer occurs between the exposed portion 2a and the unexposed portion 2b (step (2); FIG. 1 (c)).
Thereafter, development with an organic developer is performed. As a result, the exposed portion 2a of the resist film 2 remains, and the unexposed portion 2b is dissolved and removed in the organic developer. As a result, as shown in FIG. A negative resist pattern composed of the plurality of resist patterns 2a, 2a is formed (step (3); FIG. 1 (d)).

[Step (1)]
In step (1), using the resist composition (1) containing the components (A) to (C), the acidic group (carboxy group) and the component (C) (alkylamine) are formed on the support 1. And a resist film 2 having an association structure (x1) with ().
FIG. 2 is a schematic diagram showing the presence state of the components (A) to (C) in the resist film before and after exposure for the embodiment shown in FIG. 2A shows the presence state of components (A) to (C) in the resist film before exposure, and FIG. 2B shows the presence state of components (A) to (C) in the resist film after exposure. Each is shown.
As shown in FIG. 2A, in this embodiment, when the resist composition (1) is applied onto the support 1 and dried, the acidic group (—C (═O) —O in the component (A) is obtained. -H) and the alkylamine (N≡) as the component (C) interact to form an association structure (x1) in a form close to a salt, and the resist film 2 is formed. This association structure (x1) is soluble in an organic developer. In FIG. 2A, V ⁺ W ⁻ represents the component (B) composed of a cation part and an anion part, and is soluble in an organic developer.
Details of the resist composition (1) will be described later.

The support 1 is not particularly limited, and a conventionally known one can be used. Examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
In addition, the support 1 may be one in which an inorganic and / or organic film is provided on the substrate as described above, and is preferably one in which an organic film is provided. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC) and a lower layer film in a multilayer resist method. In particular, when an organic film is provided, a high aspect ratio pattern can be easily formed on a substrate, which is useful in semiconductor manufacturing and the like.
Here, the multilayer resist method is a method in which at least one organic film (lower film) and at least one resist film are provided on a substrate, and the lower layer is patterned using the resist pattern formed on the upper resist film as a mask. It is said that a high aspect ratio pattern can be formed. The multi-layer resist method basically has a two-layer structure of an upper resist film and a lower film, and one or more intermediate layers (metal thin film, etc.) are provided between these resist film and lower film. And a method of forming a multilayer structure of three or more layers. According to the multilayer resist method, by securing a required thickness with the lower layer film, the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
The inorganic film can be formed, for example, by coating an inorganic antireflection film composition such as a silicon-based material on a substrate and baking.
The organic film is, for example, a material for forming an organic film in which a resin component or the like constituting the film is dissolved in an organic solvent is applied onto a substrate with a spinner or the like, preferably 200 to 300 ° C., preferably 30 to 300. It can be formed by baking for 2 seconds, more preferably 60 to 180 seconds. The organic film forming material used at this time does not necessarily require sensitivity to light or an electron beam, such as a resist film, and may or may not have such sensitivity. Also good. Specifically, resists and resins generally used in the manufacture of semiconductor elements and liquid crystal display elements can be used.
In addition, the organic film forming material is an organic film that can be etched, particularly dry-etched, so that the organic film pattern can be formed by etching the organic film using the resist pattern. A material that can be formed is preferred. Among these, a material capable of forming an organic film capable of etching such as oxygen plasma etching is preferable. Such an organic film forming material may be a material conventionally used for forming an organic film such as an organic BARC. Examples include the ARC series manufactured by Brewer Science, the AR series manufactured by Rohm and Haas, and the SWK series manufactured by Tokyo Ohka Kogyo.

A method for coating the resist composition (1) on the support 1 to form the resist film 2 is not particularly limited, and can be formed by a conventionally known method.
For example, the resist composition (1) is applied onto the support 1 using a conventionally known method such as a spin coat method using a spin coater or a bar coat method using a bar coater, and is applied on a cooling plate or the like. The resist film 2 can be formed by drying at room temperature or by pre-baking (PAB).
When performing a prebaking process, 80-150 degreeC is preferable and temperature conditions have more preferable 80-100 degreeC. The baking time is preferably 40 to 120 seconds, more preferably 60 to 90 seconds. By performing pre-baking, the organic solvent is easily volatilized even when the resist film thickness is set to a thick film.
By drying the resist composition at room temperature and not performing pre-baking, the number of steps of resist pattern formation can be reduced.
The presence / absence of pre-baking may be appropriately determined in consideration of the above-described advantages and the like from the material of the resist composition to be used and the target of the pattern to be formed.

The film thickness of the resist film 2 formed in the step (1) is preferably 50 to 500 nm, more preferably 50 to 450 nm. By setting it within this range, there are effects that a resist pattern can be formed with high resolution and sufficient resistance to etching can be obtained.
In the case where pre-baking is not performed, the thickness of the resist film 2 formed in the step (1) is preferably 300 nm or less, and more preferably 200 nm or less. If the film thickness of the resist film 2 is less than or equal to the preferable upper limit value, the organic solvent does not easily remain even by a coating method such as spin coating at room temperature, and it becomes easy to dry. 1 in-plane uniformity).

[Step (2)]
In the step (2), the resist film 2 is exposed to form a new association structure of the acid generated from the component (B) and the component (C) (alkylamine) forming the association structure (x1). (Y1) is formed to expose the acidic group (—C (═O) —O—H).
In this embodiment, when the resist film 2 is exposed through the photomask 3 on which a predetermined pattern is formed, the cation portion (V ⁺ ) of the acid generator (V ⁺ W ⁻ ) is absorbed by light absorption in the exposed portion 2a. decomposed and acid generator ^(V + W ^-) from the acid ^(W - ^{H +)} is generated. Then, a salt exchange reaction occurs between the acid (W ⁻ H ⁺ ) generated from the acid generator (V ⁺ W ⁻ ) and the association structure (x1), as shown in FIG. , A new association structure (y1) of the acid (W ⁻ H ⁺ ) and the alkylamine (N≡) forming the association structure (x1) is formed, and the association structure (x1) is formed. The exposed acidic group (—C (═O) —O—H) is exposed. The resist film 2 in which the acidic group (—C (═O) —O—H) is exposed and the newly formed association structure (y1) are hardly soluble in an organic developer. On the other hand, the unexposed portion 2b maintains the association structure (x1) and is soluble in the organic developer. That is, the exposure reduces the solubility of the exposed portion 2a in the organic developer, while the solubility of the unexposed portion 2b in the organic developer does not change, or even if the change is small. Thereby, the dissolution contrast with respect to an organic type developing solution is obtained between the exposure part 2a and the unexposed part 2b.

Exposure, the acid-generating agent present in the exposed portion 2a ^(V + W ^-) from the acid ^(W - ^{H +)} are generated, acid - between the ^{(W H +),} the association structure (x1) As long as the salt exchange reaction occurs, a new association structure (y1) can be formed.
The wavelength used for the exposure is not particularly limited, and includes KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. A KrF excimer laser and an ArF excimer laser are preferable because a fine resist pattern can be easily formed.
The photomask 3 is not particularly limited, and a known one can be used. For example, a binary mask (Binary-Mask) in which the transmittance of the light shielding portion is 0%, or a halftone type in which the transmittance of the light shielding portion is 6%. A phase shift mask (HT-Mask) can be used. Note that the unexposed portion may be selectively formed by a halftone phase shift mask.
In general, a binary mask is used in which a chromium film, a chromium oxide film, or the like is formed on a quartz glass substrate as a light shielding portion.
The phase shift mask is a photomask provided with a portion (shifter) that changes the phase of light. Therefore, by using the phase shift mask, it is possible to suppress the incidence of light to the unexposed area, and the developer dissolution contrast between the unexposed area and the exposed area is improved. Examples of the phase shift mask include a Levenson type phase shift mask in addition to the halftone type phase shift mask. Each of these phase shift masks can be commercially available. Specifically, as a halftone phase shift mask, specifically, MoSi (molybdenum) is used as a light-shielding portion (shifter film) having a transmittance of about several to 10% (generally 6%) on a quartz glass substrate. -A film in which a silicide) film, a chromium film, a chromium oxide film, a silicon oxynitride film, or the like is formed.
In the present embodiment, the exposure is performed through the photomask 3, but the present invention is not limited to this, and the exposure may be performed without using the photomask.

Exposure of the resist film 2 may be performed by normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be performed by exposure (immersion exposure) through an immersion medium. Especially, since this process (2) can form a higher resolution resist pattern, it is preferable that it is a process exposed through an immersion medium.
In the immersion exposure, as described above, at the time of exposure, the portion between the lens, which is conventionally filled with an inert gas such as air or nitrogen, and the resist film 2 on the support 1 is determined by the refractive index of air. Exposure is performed in a state filled with a solvent (immersion medium) having a higher refractive index.
More specifically, in the immersion exposure, a solvent (immersion medium) having a refractive index larger than the refractive index of air between the resist film 2 obtained as described above and the lowermost lens of the exposure apparatus. ), And in that state, exposure (immersion exposure) is performed through a desired photomask 3.
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film 2 exposed by the immersion exposure is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than that of air and smaller than that of the resist film 2 include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferred, and those having a boiling point of 80 to 160 ° C are more preferred. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).

In the present embodiment, since the acid-decomposable group decomposition reaction in the base material component as in the past is not performed, the solubility of the exposed portion 2a in the organic developer can be changed only by exposure. It is not always necessary to perform the baking (post-exposure baking (PEB)) treatment after the film 2 is exposed. In the case where the PEB treatment is not performed, it is preferable that after the resist film 2 is formed, the operation after the step (2) is performed at room temperature (preferably around 23 ° C.).
When performing the PEB treatment, the baking temperature condition is preferably about 50 to 200 ° C, more preferably about 80 to 150 ° C, and further preferably about 90 to 130 ° C. The baking time is preferably 10 to 300 seconds, more preferably 40 to 120 seconds, and still more preferably 60 to 90 seconds.
After the exposure in step (2), a holding time at room temperature (preferably around 23 ° C.) may be optionally provided until development in step (3).

[Step (3)]
In step (3), the exposed resist film 2 is developed using a developer containing an organic solvent (organic developer).
In the present embodiment, the exposed portion 2a is left as a film by development with an organic developer, and the unexposed portion 2b is dissolved and removed in the organic developer to form a negative resist pattern.
The organic solvent contained in the organic developer used for development is not particularly limited as long as it can dissolve the resist film 2 before exposure, and can be appropriately selected from known organic solvents. Specifically, polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents and hydrocarbon solvents can be used, and ketone solvents, ester solvents, alcohol solvents. Is preferred. Among ester solvents, acetate solvents are particularly preferable.

As in this embodiment, when forming a negative resist pattern using a resist composition (1) containing a base component having a carboxy group as an acidic group, as an organic solvent contained in an organic developer, One or more types selected from the group consisting of butyl acetate, 4-methyl-2-pentanol, 1-butoxy-2-propanol, propylene glycol methyl ether acetate, and 2-heptanone are preferable.
In addition, when forming a positive resist pattern using this resist composition (1), propylene glycol methyl ether, ethyl lactate, etc. are mentioned as a suitable organic solvent which an organic type developing solution contains.

A known additive can be blended in the organic developer as required. Examples of the additive include a surfactant. Although it does not specifically limit as surfactant, For example, an ionic or nonionic fluorine type and / or silicone type surfactant etc. can be used.
When the surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0. 0% with respect to the total amount of the organic developer. 5 mass% is more preferable.
The development treatment can be carried out by a known development method, for example, a method in which a support is immersed in a developer for a certain period of time (dip method), and the developer is raised on the surface of the support by surface tension and left stationary for a certain period of time. Method (Paddle method), Method of spraying developer on the surface of support (spray method), Continuous application of developer while scanning developer coating nozzle at constant speed on support rotating at constant speed And a method (dynamic dispensing method).

A rinsing treatment is preferably performed after the development treatment. In the rinsing process, it is preferable to use a rinsing liquid containing an organic solvent. As the organic solvent contained in the rinsing liquid, for example, among the organic solvents mentioned as the organic solvent contained in the organic developer, those which are difficult to dissolve the resist pattern can be appropriately selected and used.
The rinse treatment (washing treatment) using the rinse liquid can be performed by a known rinse method. Examples of the method include a method of continuously applying a rinsing liquid on a support rotating at a constant speed (rotary coating method), a method of immersing the support in a rinsing liquid for a predetermined time (dip method), and the surface of the support. And a method of spraying a rinse liquid (spray method).
After the development process or the rinsing process, a process of removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid may be performed.
Drying is performed after development or rinsing. In some cases, a baking process (post-bake) may be performed after the development process.

  The resist pattern forming method of the present invention includes an embodiment in which a positive resist pattern is formed in addition to the embodiment shown in FIG. 1 (an embodiment in which a negative resist pattern is formed).

<Second Embodiment>
FIG. 3 shows an embodiment of a resist pattern forming method of the present invention in which a positive resist pattern is formed.
In the present embodiment, a base component having a phenolic hydroxyl group as the component (A) and an acid having an acid dissociation constant (pKa) of 0 or more by exposure, which can form an association structure with the phenolic hydroxyl group as the component (C). A resist composition (2) is used that contains an ionic compound that generates acid and an acid generator that generates an acid having higher strength than the phenolic hydroxyl group by exposure as a component (B).
First, as shown in FIG. 3A, the resist composition (2) is coated on the support 1 to form a film. When the resist composition (2) is applied onto the support 1, an association structure (x2) between the acidic group (phenolic hydroxyl group) in the base material component and the ionic compound is formed to form a resist film 2 ′. A film is formed (step (1); FIG. 3 (a)).
Next, as shown in FIG. 3B, the resist film 2 ′ formed as described above is exposed through a photomask 3 on which a predetermined pattern is formed (step (2); FIG. 3B). ).
By this exposure, an acid is generated from the acid generator in the exposed region (exposed portion 2′a) of the resist film 2 ′. As a result, a new association structure (y2) is formed between the acid generated from the acid generator and the ionic compound forming the association structure (x2), and the association structure (x2) is formed. The acidic group (phenolic hydroxyl group) that has been exposed is exposed. As a result, the solubility of the exposed portion 2′a in the organic developer increases. On the other hand, the solubility of the unexposed portion 2′b in the organic developer does not change, or even if it changes, the amount of change is slight. This causes a difference in dissolution rate (dissolution contrast) in the organic developer between the exposed portion 2′a and the unexposed portion 2′b (step (2); FIG. 3 (c)).
Thereafter, development with an organic developer is performed. As a result, the exposed portion 2′a of the resist film 2 ′ is dissolved and removed in the organic developer, and the unexposed portion 2′b is left as a result. As a result, as shown in FIG. A positive resist pattern composed of a plurality of spaced apart resist patterns 2′b and 2′b is formed thereon (step (3); FIG. 3 (d)).

[Step (1)]
In step (1), using the resist composition (2) containing the components (A) to (C), the acidic group (phenolic hydroxyl group) and the component (C) (ion) are formed on the support 1. A resist film 2 ′ having an association structure (x2) with the active compound) is formed.
FIG. 4 is a schematic diagram showing the presence of components (A) to (C) in the resist film before and after exposure for the embodiment shown in FIG. 4A shows the presence state of components (A) to (C) in the resist film before exposure, and FIG. 4B shows the presence state of components (A) to (C) in the resist film after exposure. Each is shown.
As shown in FIG. 4A, in this embodiment, when the resist composition (2) is applied on the support 1 and dried, the acidic groups (phenolic hydroxyl groups) in the component (A) and (C ) Interacts with the ionic compound (Y ⁺ Z ⁻ ), which is a component, to form an association structure (x2) in a form close to a salt, and a resist film 2 ′ is formed. This association structure (x2) is hardly soluble in an organic developer. In FIG. 4A, V ⁺ W ⁻ represents a component (B) composed of a cation portion and an anion portion, and is soluble in an organic developer. In FIG. 4, R represents a substituent, and t is an integer of 0-4.
Details of the resist composition (2) will be described later.
The description of the step (1) in the second embodiment other than the above is the same as the description of the step (1) in the first embodiment described above.

[Step (2)]
In the step (2), the resist film 2 ′ is exposed, and the acid generated from the component (B) and the component (C) (ionic compound) forming the association structure (x2) are newly formed. An association structure (y2) is formed to expose the acidic group (phenolic hydroxyl group).
In this embodiment, when the resist film 2 ′ is exposed through the photomask 3 on which a predetermined pattern is formed, the cation portion (V ⁺ ) of the acid generator (V ⁺ W ⁻ ) is formed in the exposed portion 2′a. It is decomposed by light absorption, acid generator ^(V + W ^-) from the acid ^(W - ^{H +)} is generated. Then, a salt exchange reaction occurs between the acid (W ⁻ H ⁺ ) generated from the acid generator (V ⁺ W ⁻ ) and the association structure (x2), as shown in FIG. , acid ^(W - ^{H +)} and the associated structures (x2) ionic compound to form a ^(Y + Z ^-) cation in ^{(Y +)} and new association structure (y2) is formed At the same time, the acidic group (phenolic hydroxyl group) forming the association structure (x2) is exposed. The resist film 2 ′ where the acidic group (phenolic hydroxyl group) is exposed and the newly formed association structure (y2) are soluble in the organic developer. On the other hand, the unexposed portion 2′b maintains the association structure (x2) and exhibits poor solubility in an organic developer. That is, the exposure increases the solubility of the exposed portion 2′a in the organic developer, while the solubility of the unexposed portion 2′b in the organic developer does not change or the amount of change does not change. It is slight. Thereby, the melt | dissolution contrast with respect to an organic type developing solution is obtained between exposed part 2'a and unexposed part 2'b.

The amount of exposure is such that an acid (W ⁻ H ⁺ ) is generated from the acid generator (V ⁺ W ⁻ ) present in the exposed portion 2′a, the acid (W ⁻ H ⁺ ), the association structure (x2), It is sufficient that a salt exchange reaction occurs between the two to form a new association structure (y2).
The description of the step (2) in the second embodiment other than the above is the same as the description of the step (2) in the first embodiment described above.

[Step (3)]
In step (3), the exposed resist film 2 ′ is developed using an organic developer.
In the present embodiment, the exposed portion 2′a is dissolved and removed in the organic developer by the development with the organic developer, and the unexposed portion 2′b remains to form a positive resist pattern.

When forming a positive resist pattern using a resist composition (2) containing a base component having a phenolic hydroxyl group as an acidic group as in this embodiment, the organic solvent contained in the organic developer is as follows: One or more selected from the group consisting of butyl acetate, 4-methyl-2-pentanol, 1-butoxy-2-propanol, propylene glycol methyl ether acetate, and 2-heptanone are preferable.
In addition, when forming a negative resist pattern using this resist composition (2), n-heptane, dibutyl ether, etc. are mentioned as a suitable organic solvent which an organic type developing solution contains.

  The description of the step (3) in the second embodiment other than the above is the same as the description of the step (3) in the first embodiment described above.

As described above, a resist pattern forming method in which a resist film is formed on the support 1 using the resist composition (1) or the resist composition (2), exposed, and developed with an organic developer. According to this, it is easy to obtain a good dissolution contrast between the exposed portion and the unexposed portion of the resist film, and a fine pattern can be formed.
In the resist pattern forming method of the present invention, unlike the conventional method, the acid-decomposable group in the base component does not undergo a decomposition reaction due to exposure, that is, the polarity of the base component does not change by exposure, and the organic A dissolution contrast is obtained with respect to the system developer.
Specifically, according to the resist pattern forming method of the present invention, an association structure is formed with an acidic group in the base material component using the resist composition containing the components (A) to (C). A resist film is formed with a salt exchange reaction between the association structure and the acid generated from the acid generator upon exposure, thereby controlling the solubility of the resist film exposed portion in the organic developer. The difference in solubility in the organic developer between the exposed portion and the unexposed portion of the resist film can be greatly increased.
Thus, in the resist pattern forming method of the present invention, a good dissolution contrast can be obtained by a novel resist pattern forming mechanism, and a fine pattern can be formed.

≪Resist composition≫
The resist composition of the present invention is suitable as the resist composition used in the above-described resist pattern forming method of the present invention, and forms a base material component (A) having an acidic group and an association structure with the acidic group. And an acid generator component (B) that generates an acid having higher strength than the acidic group by exposure.
In the present invention, it is determined which of the negative resist pattern and the positive resist pattern is formed by the combination of the acidic group in the component (A) and the organic developer.
The resist composition (1) used in the first embodiment described above includes a base component having a carboxy group as the component (A), and an alkylamine capable of forming an association structure with the carboxy group as the component (C). And (B) an acid generator that generates an acid having higher strength than the carboxy group by exposure. A negative resist pattern is formed by a combination of the resist composition (1) and an organic developer. That is, in the first embodiment, the resist composition (1) is a negative resist composition.
The resist composition (2) used in the second embodiment described above can form an association structure with the base component having a phenolic hydroxyl group as the component (A) and the phenolic hydroxyl group as the component (C). It contains an ionic compound that generates an acid having an acid dissociation constant (pKa) of 0 or more upon exposure, and an acid generator that generates an acid having higher strength than the phenolic hydroxyl group by exposure as component (B). A positive resist pattern is formed by a combination of the resist composition (2) and an organic developer. That is, in the second embodiment, the resist composition (2) is a positive resist composition.
As described above, depending on the type of organic developer, the resist composition (1) can be a positive resist composition and the resist composition (2) can be a negative resist composition.

[Base Component (A)]
In the present invention, the “base component” is an organic compound having a film forming ability, and preferably an organic compound having a molecular weight of 500 or more is used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
“Film-forming ability” refers to a property that can form a film by its component itself or by forming an association structure with other components.
Organic compounds used as the base material component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the “low molecular compound” refers to a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, those having a molecular weight of 1000 or more are usually used.
In the present specification and claims, the term “resin” refers to a polymer having a molecular weight of 1000 or more.
As the molecular weight of the polymer, a polystyrene-reduced mass average molecular weight by GPC (gel permeation chromatography) is used.

In the present invention, the “acidic group” means a group that easily releases H ⁺ , and includes a carboxy group; a phenolic hydroxyl group, a sulfonamide group, a sulfonylimide group, a hydroxyalkyl group substituted with an electron-withdrawing group, and the like. Illustrated.

The base material component (A) having an acidic group is not particularly limited as long as it has film-forming ability and can form an association structure with the component (C), and may be a resin component or a low molecular compound component. Or a mixture thereof.
Especially, since it is easy to form a resist film stably, as (A) component, it is preferable that it is a resin component which has film forming ability and can form an association structure with (C) component.
In addition, the resin component includes a polymer compound (A1) (hereinafter referred to as “(A1) component”) having a structural unit containing an acidic group (hereinafter this structural unit is referred to as “structural unit (a5)”). What is contained is preferable.

・ Structural unit (a5)
In the present specification, the structural unit (a5) is a structural unit containing an acidic group.
As the acidic group, a carboxy group (—COOH), a phenolic hydroxyl group (—OH), a sulfonamide group (—SO ₂ —NH ₂ ), a sulfonylimide group (—SO ₂ —NH—SO ₂ —), an electron withdrawing property And a hydroxyalkyl group substituted with a group.
As the structural unit containing a carboxy group (—COOH) as an acidic group, a hydrogen atom bonded to the α-position carbon atom is a substituent (an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or the like). ) To a structural unit derived from acrylic acid optionally substituted. Examples of the halogen atom in the halogenated alkyl group as the substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
Examples of the electron-withdrawing group in the hydroxyalkyl group substituted with the electron-withdrawing group include a fluorine atom and an oxygen atom. As the hydroxyalkyl group, a hydroxyalkyl group having 1 to 5 carbon atoms is preferable. Specifically, as the hydroxyalkyl group, a group in which part of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms is substituted with a hydroxy group. Is mentioned.

The structural unit (a5) is preferably a structural unit containing a hydrocarbon group in which some of the hydrogen atoms are substituted with acidic groups. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group in the hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group), an aliphatic cyclic group (monocyclic group, polycyclic group). Formula group).
As the aliphatic cyclic group (monocyclic group, polycyclic group), for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from those proposed. The aliphatic cyclic group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. Specifically, for example, a group in which two or more hydrogen atoms have been removed from a monocycloalkane; a group in which two or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which two or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane; two or more groups from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group having 1 to 5 carbon atoms.

The aromatic hydrocarbon group in the hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 (where n is 0 and a natural number) π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are more preferable, and 6-12 are especially preferable. However, the carbon number does not include the carbon number in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms, and the like. Can be mentioned. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specifically, the aromatic hydrocarbon group as the divalent hydrocarbon group is a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring or aromatic heterocyclic ring (arylene group or heteroarylene group); A group obtained by removing two hydrogen atoms from an aromatic compound containing an aromatic ring (for example, biphenyl, fluorene, etc.); a group in which one of the hydrogen atoms of the aromatic ring is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl groups such as 2-naphthylethyl group and heteroarylalkyl groups), groups obtained by further removing one hydrogen atom, and the like It is done. The number of carbon atoms of the alkylene group that replaces the hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1. .
The aromatic hydrocarbon group may have a substituent. For example, the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
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.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

  As the structural unit (a5), structural units represented by general formula (a5-1) shown below are preferred.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基である。Ｐ^０は−Ｃ（＝Ｏ）−Ｏ−、−Ｃ（＝Ｏ）−ＮＲ^０−（Ｒ^０は水素原子又は炭素数１〜５のアルキル基である）又は単結合である。Ｗ^０は置換基としてカルボキシ基（−ＣＯＯＨ）、フェノール性水酸基（−ＯＨ）、スルホンアミド基（−ＳＯ_２−ＮＨ_２）、スルホニルイミド基（−ＳＯ_２−ＮＨ−ＳＯ_２−）及び電子吸引性基で置換されたヒドロキシアルキル基からなる群より選択される少なくとも一種の酸性基を有する炭化水素基、又は−ＣＯＯＨである。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. P ⁰ is —C (═O) —O—, —C (═O) —NR ⁰ — (R ⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) or a single bond. W ⁰ is a carboxy group (—COOH), a phenolic hydroxyl group (—OH), a sulfonamide group (—SO ₂ —NH ₂ ), a sulfonylimide group (—SO ₂ —NH—SO ₂ —) and electron withdrawing as substituents. It is a hydrocarbon group having at least one acidic group selected from the group consisting of hydroxyalkyl groups substituted with a functional group, or -COOH. ]

In the formula (a5-1), the alkyl group of R is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which some or all of the hydrogen atoms of the aforementioned R alkyl group have been 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.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom or a methyl group.

In Formula (a5-1), P ⁰ is —C (═O) —O—, —C (═O) —NR ⁰ — (R ⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ) Or a single bond. The alkyl group for R ⁰ is the same as the alkyl group for R.

In the formula (a5-1), W ⁰ is a carboxy group (—COOH), a phenolic hydroxyl group (—OH), a sulfonamide group (—SO ₂ —NH ₂ ), a sulfonylimide group (—SO ₂ ) as a substituent. -NH-SO 2 _-) and a hydrocarbon group having at least one acidic group selected from the group consisting of substituted hydroxyalkyl group with an electron withdrawing group, or -COOH.
The “hydrocarbon group having an acidic group as a substituent” means that at least a part of hydrogen atoms bonded to the hydrocarbon group is substituted with an acidic group.
The hydrocarbon group in W ⁰ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
As the aliphatic hydrocarbon group in the hydrocarbon group of W ^0, a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group), an aliphatic cyclic group (monocyclic group, A polycyclic group (which may have a substituent) is preferably mentioned, and the description thereof is the same as described above.
The aromatic hydrocarbon group in the hydrocarbon group of W ⁰ is a hydrocarbon group (which may have a substituent) having at least one aromatic ring, and this description is the same as above.

As a preferable unit among the structural units (a5), more specifically,
A structural unit derived from acrylic acid in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent (an alkyl group having 1 to 5 carbon atoms, an alkyl halide group having 1 to 5 carbon atoms, etc.) ,
A structural unit represented by the following general formula (a5-11);
Examples include the structural unit represented by general formula (a5-12) below.

.. Structural unit derived from acrylic acid The structural unit derived from acrylic acid includes a structural unit in which P ⁰ in formula (a5-1) is a single bond and W ⁰ is —COOH. Can be mentioned.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基である。
Ｗ^０１は置換基としてカルボキシ基（−ＣＯＯＨ）、フェノール性水酸基（−ＯＨ）、スルホンアミド基（−ＳＯ_２−ＮＨ_２）、スルホニルイミド基（−ＳＯ_２−ＮＨ−ＳＯ_２−）及び電子吸引性基で置換されたヒドロキシアルキル基からなる群より選択される少なくとも一種の酸性基を有する芳香族炭化水素基である。
Ｐ^０２は−Ｃ（＝Ｏ）−Ｏ−、−Ｃ（＝Ｏ）−ＮＲ^０−（Ｒ^０は水素原子又は炭素数１〜５のアルキル基である）又は単結合である。
Ｗ^０２は置換基としてカルボキシ基（−ＣＯＯＨ）、フェノール性水酸基（−ＯＨ）、スルホンアミド基（−ＳＯ_２−ＮＨ_２）、スルホニルイミド基（−ＳＯ_２−ＮＨ−ＳＯ_２−）及び電子吸引性基で置換されたヒドロキシアルキル基からなる群より選択される少なくとも一種の酸性基を有する環状の炭化水素基である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
W ⁰¹ is a carboxy group (—COOH), a phenolic hydroxyl group (—OH), a sulfonamide group (—SO ₂ —NH ₂ ), a sulfonylimide group (—SO ₂ —NH—SO ₂ —) and electron withdrawing as substituents. An aromatic hydrocarbon group having at least one acidic group selected from the group consisting of hydroxyalkyl groups substituted with a functional group.
P ⁰² is —C (═O) —O—, —C (═O) —NR ⁰ — (R ⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) or a single bond.
^W02 is a carboxy group (—COOH), a phenolic hydroxyl group (—OH), a sulfonamide group (—SO ₂ —NH ₂ ), a sulfonylimide group (—SO ₂ —NH—SO ₂ —) and an electron withdrawing group as substituents. A cyclic hydrocarbon group having at least one acidic group selected from the group consisting of hydroxyalkyl groups substituted with a functional group. ]

.. Structural unit represented by general formula (a5-11) In the formula (a5-11), R is the same as the description of R in the formula (a5-1).
The aromatic hydrocarbon group in W ⁰¹ is the same as the description of the aromatic hydrocarbon group in the hydrocarbon group of W ⁰ in the formula (a5-1).
Specific examples of preferable structural units represented by general formula (a5-11) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

.. Structural unit represented by general formula (a5-12) In the formula (a5-12), R is the same as the description of R in the formula (a5-1).
P ⁰² is —C (═O) —O— or —C (═O) —NR ⁰ — (R ⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), and —C (═O ) -O-. The alkyl group for R ⁰ is the same as the alkyl group for R.
The cyclic hydrocarbon group in W ⁰² is an aliphatic cyclic group (monocyclic group or polycyclic group) or aromatic hydrocarbon exemplified in the description of W ⁰ in the formula (a5-1). Examples of each group are the same.
Specific examples of preferable structural units represented by general formula (a5-12) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The structural unit (a5) contained in the component (A1) may be a single type or two or more types.
Among these, as the structural unit (a5), a structural unit containing a carboxy group (—COOH) or a phenolic hydroxyl group (—OH) as an acidic group is easily formed because an association structure with the component (C) is easily formed. preferable.
When the component (A1) is a copolymer composed of the structural unit (a5) and other structural units, the proportion of the structural unit (a5) in the component (A1) is the total of the component (A1). The content is preferably 5 mol% or more, more preferably 10 to 60 mol%, and still more preferably 15 to 50 mol% with respect to the structural unit.
When the proportion of the structural unit (a5) is at least the lower limit value, an association structure with the component (C) is easily formed, and the resist film is more stably formed. On the other hand, by being below the upper limit value, it becomes easy to balance with other structural units.
In the component (A1), the proportion of the structural unit (a5) may be 100 mol%. That is, as the component (A1), a homopolymer composed of repeating units of the structural unit (a5) can be used.

-Other structural unit (A1) A component may have other structural units other than said structural unit (a5) according to a use within the range which does not impair the effect of this invention.
Such other structural unit is not particularly limited as long as it is a structural unit that is not classified as the above-mentioned structural unit, and it is used for resist resins such as for ArF excimer laser and for KrF excimer laser (preferably for ArF excimer laser). Many things conventionally known as what is used can be used.
Examples of such other structural units include a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid, a structural unit (a2) containing a —SO ₂ -containing cyclic group or a lactone-containing cyclic group, And a structural unit (a4) containing an acid non-dissociable cyclic group.

..Structural unit (a1)
In the present specification, the structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.
In the resist composition of the present invention, the component (A1) may further have a structural unit (a1) in addition to the structural unit (a5).
In the present invention, unlike the conventional case, since a resist pattern can be formed without undergoing a decomposition reaction due to exposure of an acid-decomposable group in the base material component, it is necessary to have the structural unit (a1) in the base resin. Although not required, a polymer compound having a structural unit (a1) in addition to the structural unit (a5) may be used according to the required lithography properties.

The “acid-decomposable group” in the structural unit (a1) is an acid-decomposable group that can cleave at least part of the bonds in the structure of the acid-decomposable group by the action of an acid.
Examples of the acid-decomposable group whose polarity increases by the action of an acid include a group that decomposes by the action of an acid to generate a polar group.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (—SO ₃ H), and the like. Among these, a polar group containing —OH in the structure (hereinafter sometimes referred to as “OH-containing polar group”) is preferable, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable.
More specifically, examples of the acid-decomposable group include a group in which the polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).
The “acid-dissociable group” is a group having an acid-dissociable property capable of cleaving at least a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by the action of an acid. The acid-dissociable group constituting the acid-decomposable group needs to be a group having a lower polarity than the polar group generated by dissociation of the acid-dissociable group. Is dissociated, a polar group having a polarity higher than that of the acid dissociable group is generated to increase the polarity. As a result, the polarity of the entire component (A1) is further increased. As the polarity further increases, the change in solubility in an organic developer becomes relatively large.

The acid-dissociable group is not particularly limited, and those that have been proposed as acid-dissociable groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable group such as an alkoxyalkyl group is widely known.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (═O The structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of) -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom to form a carboxy group.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable group include an aliphatic branched acid dissociable group and an acid dissociable group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable group include a group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically a tert-butyl group or a 2-methyl-2-butyl group. , 2-methyl-2-pentyl group, 3-methyl-3-pentyl group and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group in the “acid-dissociable group containing an aliphatic cyclic group” may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. Is mentioned.
The basic ring structure excluding the substituent of the aliphatic cyclic group is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be monocyclic or polycyclic.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. A group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, or tetracycloalkane; More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. An alicyclic hydrocarbon group such as a group excluding a hydrogen atom is exemplified. Moreover, a part of carbon atoms constituting the ring of these alicyclic hydrocarbon groups may be substituted with an ether group (—O—).

Examples of the acid dissociable group containing an aliphatic cyclic group include:
(I) On the ring skeleton of the monovalent aliphatic cyclic group, the substituent ( An atom or group other than a hydrogen atom) to form a tertiary carbon atom;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto.
In the group (i), examples of the substituent bonded to the carbon atom bonded to the atom adjacent to the acid dissociable group on the ring skeleton of the aliphatic cyclic group include an alkyl group. Examples of the alkyl group include those similar to R ¹⁴ in formulas (1-1) to (1-9) described later.
Specific examples of the group (i) include groups represented by the following general formulas (1-1) to (1-9).
Specific examples of the group (ii) include groups represented by the following general formulas (2-1) to (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

[Wherein, R ¹⁴ represents an alkyl group, and g represents an integer of 0 to 8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

In formulas (1-1) to (1-9), the alkyl group of R ¹⁴ may be linear, branched or cyclic, and is preferably linear or branched.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and still more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.
In formulas (2-1) to (2-6), examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those described above for R ¹⁴ .
In the formulas (1-1) to (1-9) and (2-1) to (2-6), a part of the carbon atoms constituting the ring is substituted with an etheric oxygen atom (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

The “acetal-type acid dissociable group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an OH-containing polar group such as a carboxy group or a hydroxyl group. Then, the acid acts to cut the bond between the acetal acid dissociable group and the oxygen atom to which the acetal acid dissociable group is bonded, and OH-containing polar groups such as a carboxy group and a hydroxyl group are formed. The
Examples of the acetal type acid dissociable group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｙは炭素数１〜５のアルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ 'and R ² ' each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and Y represents an alkyl group having 1 to 5 carbon atoms. Or represents an aliphatic cyclic group. ]

In formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group for R ¹ ′ and R ² ′ include linear groups such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, and neopentyl group. Or a branched alkyl group, a methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

As the alkyl group of Y, linear or branched chain such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, etc. An alkyl group is mentioned.
The aliphatic cyclic group for Y can be appropriately selected and used from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists. Examples thereof are the same as the aliphatic cyclic groups mentioned in “Acid-dissociable groups containing formula groups”.

  Examples of the acetal type acid dissociable group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状若しくは分岐鎖状のアルキル基または水素原子であり；Ｒ^１９は直鎖状、分岐鎖状若しくは環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状若しくは分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represents a linear or branched alkyl group or a hydrogen atom; and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group. And the like, in which a hydrogen atom is removed. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the formula (p2), R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ¹⁹ is The terminal of R ¹⁷ may be bonded.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

The structural unit (a1) is not particularly limited as long as it has an acid-decomposable group, but an acrylic group in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. A structural unit derived from an acid ester and comprising a structural unit (a11) containing an acid-decomposable group, a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and hydrogen bonded to a benzene ring A structural unit in which a hydrogen atom of a hydroxyl group of a structural unit derived from hydroxystyrene which may be substituted with a substituent other than a hydroxyl group is substituted with an acid-dissociable group or a substituent containing an acid-dissociable group ( a12), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the naphthalene ring may be substituted with a substituent other than a hydroxyl group (hydroxynaphtho Like structural units hydroxyl hydrogen atoms of constituent units derived from alkylene) is replaced by a substituent containing an acid-dissociable group or an acid-dissociable group (a13) are preferably exemplified.
Among these, the structural unit (a11) is preferable in terms of roughness improvement (reduction in line width roughness and line edge roughness), and the structural unit (a12) or structural unit (a13) is preferable in terms of exposure light absorption control.

Here, in the present specification, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid ester” is a compound in which the hydrogen atom at the carboxy group terminal of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
In the acrylate ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent that replaces the hydrogen atom bonded to the α-position carbon atom is an atom or group other than a hydrogen atom, such as an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or a hydroxy group. An alkyl group etc. are mentioned. The α-position carbon atom of the acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
Hereinafter, acrylic acid and acrylic ester in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent may be referred to as α-substituted acrylic acid and α-substituted acrylic ester, respectively. In addition, acrylic acid and α-substituted acrylic acid may be collectively referred to as “(α-substituted) acrylic acid”, and acrylic acid ester and α-substituted acrylic acid ester may be collectively referred to as “(α-substituted) acrylic acid ester”. .
In the α-substituted acrylate ester, the alkyl group as a substituent at the α-position is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, n- Examples thereof include a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group.
Specific examples of the halogenated alkyl group as the substituent at the α-position include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α-position” are substituted with a halogen atom. It is done. 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.
Bonded to the α-position of the α-substituted acrylate ester is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. An alkyl group or a fluorinated alkyl group having 1 to 5 carbon atoms is more preferred, and a hydrogen atom or a methyl group is most preferred from the viewpoint of industrial availability.

The “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene.
Hydroxystyrene is a compound in which one vinyl group and at least one hydroxyl group are bonded to a benzene ring. 1-3 are preferable and, as for the number of the hydroxyl groups couple | bonded with a benzene ring, 1 is especially preferable. The bonding position of the hydroxyl group in the benzene ring is not particularly limited. When the number of hydroxyl groups is one, the para 4-position of the vinyl group bonding position is preferred. When the number of hydroxyl groups is an integer of 2 or more, any bonding position can be combined.
The “structural unit derived from vinyl (hydroxynaphthalene)” means a structural unit configured by cleavage of an ethylenic double bond of vinyl (hydroxynaphthalene).
Vinyl (hydroxynaphthalene) is a compound in which one vinyl group and at least one hydroxyl group are bonded to a naphthalene ring. The vinyl group may be bonded to the 1-position of the naphthalene ring or may be bonded to the 2-position. 1-3 are preferable and, as for the number of the hydroxyl groups couple | bonded with a naphthalene ring, 1 is especially preferable. The bonding position of the hydroxyl group in the naphthalene ring is not particularly limited. In the case where a vinyl group is bonded to the 1-position or 2-position of the naphthalene ring, any one of the 5- to 8-positions of the naphthalene ring is preferable. In particular, when the number of hydroxyl groups is one, any one of 5 to 7 positions of the naphthalene ring is preferable, and 5 or 6 positions are preferable. When the number of hydroxyl groups is an integer of 2 or more, any bonding position can be combined.

... Structural unit (a11):
The structural unit (a11) is a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent and includes an acid-decomposable group.
Examples of the structural unit (a11) include a structural unit represented by the following general formula (a1-0-1), a structural unit represented by the following general formula (a1-0-2), and the like.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；Ｘ^１は酸解離性基であり；Ｙ^２は２価の連結基であり；Ｘ^２は酸解離性基である。］

Wherein R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; X ¹ is an acid dissociable group; Y ² is a divalent linking group. Yes; X ² is an acid-dissociable group. ]

In the general formula (a1-0-1), as the alkyl group having 1 to 5 carbon atoms of R, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl A linear or branched alkyl group such as a group, an isopentyl group and a neopentyl group.
Examples of the halogenated alkyl group having 1 to 5 carbon atoms for R include groups in which part or all of the hydrogen atoms of the above alkyl group having 1 to 5 carbon atoms have been 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.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group.

X ¹ is not particularly limited as long as it is an acid dissociable group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable groups, acetal type acid dissociable groups, and the like. An ester type acid dissociable group is preferred.
In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Examples of the divalent linking group of Y ^2, but are not limited to, divalent hydrocarbon group which may have a substituent group, and a divalent linking group containing a hetero atom as preferred.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with a substituent (a group or atom other than a hydrogen atom).
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.

The aliphatic hydrocarbon group as the divalent hydrocarbon group in Y ² may be saturated or unsaturated, and is usually preferably saturated.
More specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, more preferably 1 to 4, and most preferably 1 to 3.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —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) -, - 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 -, - C (CH 2 CH _{3) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
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 substituted with a fluorine atom, an oxygen atom (= O), and the like.

Examples of the aliphatic hydrocarbon group containing a ring in the structure include an alicyclic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and an alicyclic hydrocarbon group that is linear or branched. Examples thereof include a group bonded to the end of a chain aliphatic hydrocarbon group and a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include those described above.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.
The alicyclic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

The aromatic hydrocarbon group as the divalent hydrocarbon group in Y ² is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. . However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic ring of the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; some of the carbon atoms constituting the aromatic hydrocarbon ring are heterogeneous Aromatic heterocycles substituted with atoms; and the like. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.
Specifically, the aromatic hydrocarbon group is a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group); a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring (aryl group) ) In which one of the hydrogen atoms is substituted with an alkylene group (for example, arylalkyl such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.) And a group obtained by further removing one hydrogen atom from the aryl group in the group). The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.
The aromatic hydrocarbon group may or may not have a substituent. For example, a hydrogen atom bonded to the aromatic hydrocarbon ring of the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
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, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The hetero atom in the “divalent linking group containing a hetero atom” of Y ² is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
As the divalent linking group containing a hetero atom, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (= O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, —S (═O) _{2 -O -, - NH-C} (= O) -, = N-, the formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O] m '-Y 22 - Or a group represented by —Y ²¹ —O—C (═O) —Y ²² —, wherein Y ²¹ and Y ²² are each independently a divalent hydrocarbon group optionally having a substituent. O is an oxygen atom, and m ′ is an integer of 0 to 3. ] Etc. are mentioned.
When Y ² is —NH—, H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
Formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O] m '-Y 22 - or ^{-Y 21 -O-C (= O} ) -Y 22 - ^{In, Y 21} And Y ²² are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same groups as those described above as the “divalent hydrocarbon group which may have a substituent” for Y ² .
Y ²¹ is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group. preferable.
Y ²² is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² —, m ′ is an integer of 0 to 3, preferably an integer of 0 to 2, Or 1 is more preferable, and 1 is particularly preferable. That is, the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — is represented by the formula —Y ²¹ —C (═O) —O—Y ²² —. The group is particularly preferred. Among these, a group represented by the formula — (CH ₂ ) _{a ′} —C (═O) —O— (CH ₂ ) _{b ′} — is preferable. In the formula, a ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, more preferably 1 or 2, and most preferably 1.
Examples of the divalent linking group containing a hetero atom, a linear group containing an oxygen atom as a hetero atom, for example, a group containing an ether bond or an ester bond, are preferred, the formula -Y 21 ^-O-Y 22 ^-, A group represented by — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is more preferable.

Among these, Y ² is preferably a linear or branched alkylene group or a divalent linking group containing a hetero atom, and is a linear or branched alkylene group, the formula -Y ²¹ A group represented by —O—Y ²² —, a group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² —, or a group represented by the formula —Y ²¹ —O—C ( The group represented by ═O) —Y ²² — is more preferable.

  More specifically, examples of the structural unit (a11) include structural units represented by general formulas (a1-1) to (a1-4) shown below.

［式中、Ｒ、Ｒ^１’、Ｒ^２’、ｎ、ＹおよびＹ^２はそれぞれ前記と同じであり、Ｘ’は第３級アルキルエステル型酸解離性基を表す。］’

[Wherein, R, R ¹ ′, R ² ′, n, Y and Y ² are the same as defined above, and X ′ represents a tertiary alkyl ester-type acid dissociable group. ] '

In the formula, X ′ is the same as the tertiary alkyl ester-type acid dissociable group.
^{R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable group" described above ^{(p1) ', R 2'} , n, similarly to the Y Can be mentioned.
Y ² include the same as ^{Y 2} in the general formula (a1-0-2).
Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the present invention, as the structural unit (a11),
It is selected from the group consisting of structural units represented by the following general formulas (a1-0-11) to (a1-0-15) and structural units represented by the following general formula (a1-0-2), respectively. Preferably having at least one,
Structural units represented by the following general formula (a1-0-11), structural units represented by the following general formula (a1-0-12), structural units represented by the following general formula (a1-0-13) And at least one selected from the group consisting of structural units represented by general formula (a1-0-2) shown below.
Among these, a structural unit represented by the formula (a1-0-11), a structural unit represented by the following general formula (a1-0-12), and a structure represented by the following general formula (a1-0-2) It is particularly preferred to have at least one selected from the group consisting of units.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２１はアルキル基であり、Ｒ^２２は、当該Ｒ^２２が結合した炭素原子と共に脂肪族単環式基を形成する基であり、Ｒ^２３は分岐鎖状のアルキル基であり、Ｒ^２４は、当該Ｒ^２４が結合した炭素原子と共に脂肪族多環式基を形成する基であり、Ｒ^２５は炭素数１〜５の直鎖状のアルキル基である。Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²¹ is an alkyl group, and R ²² is a carbon to which R ²² is bonded. A group that forms an aliphatic monocyclic group together with an atom; R ²³ is a branched alkyl group; and R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded. R ²⁵ is a linear alkyl group having 1 to 5 carbon atoms. R ¹⁵ and R ¹⁶ are each independently an alkyl group. Y ² is a divalent linking group, and X ² is an acid dissociable group. ]

In each formula, the description of R, Y ² and X ² is the same as described above.
In formula (a1-0-11), examples of the alkyl group for R ²¹ include the same alkyl groups as those described above for R ¹⁴ in formulas (1-1) to (1-9). Group or isopropyl group is preferred.
R ²² is, the aliphatic monocyclic group formed together with the carbon atom to which R ²² is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable groups, a monocyclic group The thing similar to what is is mentioned. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a 3- to 11-membered ring, more preferably a 3- to 8-membered ring, further preferably a 4- to 6-membered ring, and particularly preferably a 5- or 6-membered ring.
In the monocycloalkane, a part of carbon atoms constituting the ring may or may not be substituted with an ether group (—O—).
Moreover, this monocycloalkane may have a C1-C5 alkyl group, a fluorine atom, or a C1-C5 fluorinated alkyl group as a substituent.
Examples of R ²² constituting such an aliphatic monocyclic group include a linear alkylene group in which an ether group (—O—) may be interposed between carbon atoms.

Specific examples of the structural unit represented by the formula (a1-0-11) include the formulas (a1-1-16) to (a1-1-23), (a1-1-27), and (a1-1 -31)-the structural unit represented by (a1-1-33) is mentioned. Among these, the formulas (a1-1-16) to (a1-1-17), (a1-1-20) to (a1-1-23), (a1-1-27), (a1-1-1- The structural unit represented by the following (a1-1-02) including the structural units represented by 31) to (a1-1-33) is preferable. Moreover, the structural unit represented by the following (a1-1-02 ′) is also preferable.
In each formula, h is preferably 1 or 2.

［式中、Ｒ、Ｒ^２１はそれぞれ前記と同じであり、ｈは１〜４の整数である。］

[Wherein, R and R ²¹ are the same as defined above, and h is an integer of 1 to 4, respectively. ]

In formula (a1-0-12), as the branched alkyl group for R ²³ , the branched alkyl group described for the alkyl group for R ¹⁴ in formulas (1-1) to (1-9) above. Examples thereof are the same as those described above, and an isopropyl group is most preferable.
R ²⁴ is, the aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable group, polycyclic group The thing similar to what is is mentioned.
Specific examples of the structural unit represented by the formula (a1-0-12) include those represented by the formulas (a1-1-26) and (a1-1-28) to (a1-1-30). Units are listed.
As the structural unit represented by the formula (a1-0-12), those in which R ²⁴ is an aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded are preferably a 2-adamantyl group, The structural unit represented by the formula (a1-1-26) is preferable.

In formula (a1-0-13), R and R ²⁴ are the same as defined above.
Examples of the linear alkyl group for R ²⁵ include the same linear alkyl groups as those described above for the alkyl group for R ^{14 in} the formulas (1-1) to (1-9), and methyl Most preferred are groups or ethyl groups.
Specific examples of the structural unit represented by formula (a1-0-13) include formulas (a1-1-1) to (a1-1-3) exemplified as specific examples of general formula (a1-1). ), Structural units represented by (a1-1-7) to (a1-1-15).
As the structural unit represented by the formula (a1-0-13), those in which R ²⁴ is an aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded are preferably a 2-adamantyl group, The structural unit represented by the formula (a1-1-1), (a1-1-2) or (a1-1-9) is preferable.

In formula (a1-0-14), R and R ²² are the same as defined above. R ¹⁵ and ^{R 16} are the same as ^{R 15} and ^{R 16} in each of the general formulas (2-1) to (2-6).
Specific examples of the structural unit represented by the formula (a1-0-14) include the formulas (a1-1-35) and (a1-1-36) exemplified as specific examples of the general formula (a1-1). ).

In formula (a1-0-15), R and R ²⁴ are the same as defined above. R ¹⁵ and ^{R 16} are the same as ^{R 15} and ^{R 16} in each of the general formulas (2-1) to (2-6).
Specific examples of the structural unit represented by formula (a1-0-15) include formulas (a1-1-4) to (a1-1-6) exemplified as specific examples of general formula (a1-1). ) And (a1-1-34).

Examples of the structural unit represented by the formula (a1-0-2) include the structural unit represented by the formula (a1-3) or (a1-4), and particularly represented by the formula (a1-3). Are preferred.
As the structural unit represented by the formula (a1-0-2), in particular, Y ² in the formula is a group represented by the formula —Y ²¹ —O—Y ²² —, or the formula — [Y ²¹ —C _{(= O) -O] m '} -Y 22 - group represented by or the formula ^{-Y 21 -O-C (= O} ) -Y 22, - what is a group represented by are preferred.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a1-3-01); a structural unit represented by the following general formula (a1-3-02); 3-03) and the like.

［式中、Ｒは前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、Ｒ^１４はアルキル基であり、ｙは１〜１０の整数であり、ｎ’は０〜３の整数である。］

[Wherein, R is the same as above, R ¹³ is a hydrogen atom or a methyl group, R ¹⁴ is an alkyl group, y is an integer of 1 to 10, and n ′ is an integer of 0 to 3] is there. ]

［式中、Ｒは前記と同じであり、Ｙ^２’およびＹ^２”はそれぞれ独立して２価の連結基であり、Ｘ’は酸解離性基であり、ｗは０〜３の整数である。］

[Wherein, R is the same as defined above, Y ² ′ and Y ² ″ are each independently a divalent linking group, X ′ is an acid-dissociable group, and w is an integer of 0 to 3] is there.]

In formulas (a1-3-01) to (a1-3-02), R ¹³ is preferably a hydrogen atom.
R ¹⁴ is the same as ^{R 14} in the formula (1-1) to (1-9).
y is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and most preferably 1 or 2.
n ′ is preferably 1 or 2, and most preferably 2.
Specific examples of the structural unit represented by the formula (a1-3-01) include structural units represented by the formulas (a1-3-25) to (a1-3-26).
Specific examples of the structural unit represented by the formula (a1-3-02) include structural units represented by the formulas (a1-3-27) to (a1-3-28).

In formula (a1-3-03), examples of the divalent linking group for Y ² ′ and Y ² ″ include the same groups as those described above for Y ² in formula (a1-3).
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and even more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group and an ethylene group are most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable group in X ′ include the same groups as described above, and are preferably tertiary alkyl ester-type acid dissociable groups. In addition, a group in which a substituent is bonded to a carbon atom bonded to an atom adjacent to the acid dissociable group to form a tertiary carbon atom is more preferable. Preferred are the groups
w is an integer of 0 to 3, and w is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.
As the structural unit represented by the formula (a1-3-03), a structural unit represented by the following general formula (a1-3-03-1) or (a1-3-03-2) is preferable. The structural unit represented by the formula (a1-3-03-1) is preferable.

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、ａ’は１〜１０の整数であり、ｂ’は１〜１０の整数であり、ｎ’は０〜３の整数である。］

[Wherein, R and R ¹⁴ are the same as defined above, a ′ is an integer of 1 to 10, b ′ is an integer of 1 to 10, and n ′ is an integer of 0 to 3, respectively] ]

In formulas (a1-3-03-1) to (a1-3-03-2), a ′ is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and particularly preferably 1 or 2.
b ′ is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and particularly preferably 1 or 2.
n ′ is preferably an integer of 1 to 3, particularly preferably 1 or 2.
Specific examples of the structural unit represented by formula (a1-3-03-1) or (a1-3-03-2) include those represented by formulas (a1-3-29) to (a1-3-32). The structural unit represented is mentioned.

... Structural unit (a12):
In the structural unit (a12), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the benzene ring may be substituted with a substituent other than a hydroxyl group. It is a structural unit in which a hydrogen atom of a hydroxyl group of a structural unit derived from styrene is substituted with an acid dissociable group or a substituent containing an acid dissociable group.
Examples of the acid dissociable group for substituting the hydrogen atom of the hydroxyl group include the same groups as those described above, preferably a tertiary alkyl ester type acid dissociable group or an acetal type acid dissociable group, and an acetal type acid dissociable group is More preferred.
Examples of the substituent containing an acid dissociable group include a group composed of an acid dissociable group and a divalent linking group. Examples of the divalent linking group include the same divalent linking groups as those represented by Y ² in the formula (a1-0-2). Particularly, the terminal structure on the acid dissociable group side is a carbonyloxy group. Certain groups are preferred. In this case, it is preferable that an acid dissociable group is bonded to the oxygen atom (—O—) of the carbonyloxy group.
Examples of the substituent containing an acid dissociable group include a group represented by R ¹¹ ′ —O—C (═O) — and a group represented by R ¹¹ ′ —O—C (═O) —R ¹² ′ —. Is preferred. In the formula, R ¹¹ ′ is an acid dissociable group, and R ¹² ′ is a linear or branched alkylene group.
The acid dissociable group for R ¹¹ ′ is preferably a tertiary alkyl ester type acid dissociable group or an acetal type acid dissociable group, more preferably a tertiary alkyl ester type acid dissociable group. As a preferable example of the tertiary alkyl ester type acid dissociable group, the aliphatic branched acid dissociable group represented by the above-described —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ), the formula (1- Examples include groups represented by 1) to (1-9), groups represented by formulas (2-1) to (2-6), and the like.
Examples of the alkylene group for R ¹² ′ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group. R ¹² ′ is preferably a linear alkylene group.

... Structural unit (a13):
In the structural unit (a13), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the naphthalene ring may be substituted with a substituent other than a hydroxyl group. It is a structural unit formed by replacing the hydrogen atom of the hydroxyl group of a structural unit derived from (hydroxynaphthalene) with an acid-dissociable group or a substituent containing an acid-dissociable group.
In the structural unit (a13), examples of the acid dissociable group for substituting a hydrogen atom of a hydroxyl group and the substituent containing an acid dissociable group include the same groups as those described above for the structural unit (a12). It is done.

When the component (A1) has the structural unit (a1), the structural unit (a1) may be one type or two or more types.
In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 70 mol%, more preferably 15 to 60 mol%, and more preferably 20 to 60 mol% with respect to all the structural units constituting the component (A1). Is more preferable.
By setting the ratio of the structural unit (a1) to the lower limit value or more, a pattern can be easily obtained when a resist composition is formed, and the lithography properties such as sensitivity, resolution, and pattern shape are improved. In addition, by setting the upper limit value or less, it is possible to balance with other structural units.
Especially, when the acidic group in a structural unit (a5) is a phenolic hydroxyl group, it is preferable that the ratio of a structural unit (a1) is 0-10 mol%, and it is more preferable that it is 0 mol%. The smaller the proportion of the structural unit (a1), the better the dissolution contrast.

..Structural unit (a2)
In addition to the structural unit (a5) or the structural units (a5) and (a1), the component (A1) further includes a structural unit (a2) containing a —SO ₂ -containing cyclic group or a lactone-containing cyclic group. It is preferable to have.
The —SO ₂ — containing cyclic group or the lactone containing cyclic group of the structural unit (a2) is effective in enhancing the adhesion of the resist film to the substrate when the component (A1) is used for forming the resist film. It is a thing.
In addition, when the structural unit (a5) or (a1) includes a —SO ₂ — containing cyclic group or a lactone-containing cyclic group in the structure, the structural unit also corresponds to the structural unit (a2). Such a structural unit corresponds to the structural unit (a5) or (a1) and does not correspond to the structural unit (a2).

Here, the “—SO ₂ -containing cyclic group” refers to a cyclic group containing a ring containing —SO ₂ — in the ring skeleton, specifically, a sulfur atom in —SO ₂ — ( S) is a cyclic group that forms part of the ring skeleton of the cyclic group. The ring containing —SO ₂ — in the ring skeleton is counted as the first ring, and when it is only the ring, it is a monocyclic group, and when it has another ring structure, it is a polycyclic group regardless of the structure. Called. The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
-SO ₂ - containing cyclic group, in particular, -O-SO ₂ - within the ring skeleton cyclic group containing, i.e. -O-SO ₂ - -O-S- medium is a part of the ring skeleton It is preferably a cyclic group containing a sultone ring to be formed.
The —SO ₂ — containing cyclic group preferably has 3 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, still more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. preferable. However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The —SO ₂ — containing cyclic group may be an —SO ₂ — containing aliphatic cyclic group or an —SO ₂ — containing aromatic cyclic group. Preferably -SO ₂ - containing aliphatic cyclic group.
The —SO ₂ -containing aliphatic cyclic group includes at least a hydrogen atom from an aliphatic hydrocarbon ring in which a part of carbon atoms constituting the ring skeleton is substituted with —SO ₂ — or —O—SO ₂ —. One group is excluded. More specifically, a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, —CH ₂ — constituting the ring And a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which CH ₂ — is substituted with —O—SO ₂ —.
The alicyclic hydrocarbon ring preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon ring may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms. Examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon ring, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane. , Tricyclodecane, tetracyclododecane and the like.

The —SO ₂ — containing cyclic group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), —COOR ″, —OC (═O) R ″, a hydroxyalkyl group, a cyano group, and the like. Is mentioned.
The alkyl group as the substituent is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include 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 isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group as the said substituent is mentioned.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group for the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
Examples of the halogenated alkyl group as the substituent include a group in which part or all of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent are substituted with the halogen atom. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.
R ″ in —COOR ″ and —OC (═O) R ″ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Alternatively, one or more hydrogen atoms are removed from a polycycloalkane such as a monocycloalkane, bicycloalkane, tricycloalkane, or tetracycloalkane which may or may not be substituted with a fluorinated alkyl group. More specifically, one or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Group.
The hydroxyalkyl group as the substituent is preferably one having 1 to 6 carbon atoms. Specifically, at least one of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent is substituted with a hydroxyl group. Group.
More specifically, examples of the —SO ₂ -containing cyclic group include groups represented by the following general formulas (3-1) to (3-4).

［式中、Ａ’は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｚは０〜２の整数であり、Ｒ^２７はアルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基である。］

[In the formula, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, z is an integer of 0 to 2, and R ²⁷ is an alkyl group. , An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]

In the general formulas (3-1) to (3-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, such as —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
z may be any of 0 to 2, and is most preferably 0.
When z is 2, the plurality of R ²⁷ may be the same or different from each other.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ²⁷ , the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted.

  Below, the specific cyclic group represented by the said general formula (3-1)-(3-4) is illustrated. In the formula, “Ac” represents an acetyl group.

Among the above, the —SO ₂ -containing cyclic group is preferably a group represented by the general formula (3-1), and the chemical formulas (3-1-1), (3-1-18), ( It is more preferable to use at least one selected from the group consisting of groups represented by any of 3-3-1) and (3-4-1), and represented by the chemical formula (3-1-1). Are most preferred.

The “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —O—C (═O) — in the ring skeleton. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
The lactone-containing cyclic group in the structural unit (a2) is not particularly limited, and any lactone-containing cyclic group can be used. Specifically, the lactone-containing monocyclic group is a group obtained by removing one hydrogen atom from a 4- to 6-membered ring lactone, such as a group obtained by removing one hydrogen atom from β-propionolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

The structural unit (a2) is not particularly limited as long as it has a —SO ₂ — containing cyclic group or a lactone-containing cyclic group, but the hydrogen atom bonded to the α-position carbon atom is A structural unit derived from an acrylate ester optionally substituted with a substituent, including a structural unit (a2 ^S ) containing a —SO ₂ -containing cyclic group, and a hydrogen atom bonded to the α-position carbon atom; At least one structural unit selected from the group consisting of a structural unit (a2 ^L ) that is a structural unit derived from an acrylate ester that may be substituted with a substituent and that contains a lactone-containing cyclic group is preferred.

... Structural unit (a2 ^S ):
More specifically, examples of the structural unit (a2 ^S ) include structural units represented by general formula (a2-0) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２６は−Ｏ−又は−ＮＨ−であり、Ｒ^２８は−ＳＯ_２−含有環式基であり、Ｒ^２９は単結合または２価の連結基である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²⁶ represents —O— or —NH—, and R ²⁸ represents —SO ₂ -Containing cyclic group, R ²⁹ is a single bond or a divalent linking group. ]

In formula (a2-0), R is the same as defined above.
R ²⁶ is —O— or —NH—.
R ²⁸ is the same as the —SO ₂ — containing cyclic group mentioned above.
R ²⁹ may be a single bond or a divalent linking group. Since it is excellent in the effect of this invention, it is preferable that it is a bivalent coupling group.
Examples of the divalent linking group for R ^29, not particularly limited, for example, those similar to the divalent linking group for ^{Y 2} in the formula (a1-0-2) in the like. Among these, those containing an alkylene group or an ester bond (—C (═O) —O—) are preferable.
The alkylene group is preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group exemplified as the aliphatic hydrocarbon group for Y ² in the formula (a1-0-2) can be given.
As the divalent linking group containing an ester bond, in particular, the general formula: —R ³⁰ —C (═O) —O— [wherein R ³⁰ is a divalent linking group. ] Is preferable. That is, the structural unit (a2 ^S ) is preferably a structural unit represented by the following general formula (a2-0-1).

［式中、Ｒ、Ｒ^２６およびＲ^２８はそれぞれ前記と同様であり、Ｒ^３０は２価の連結基である。］

[Wherein, R, R ²⁶ and R ²⁸ are the same as defined above, and R ³⁰ represents a divalent linking group. ]

R ³⁰ is not particularly limited, and examples thereof include those similar to the divalent linking group for Y ² in the formula (a1-0-2).
As the divalent linking group for R ^30, a linear or branched alkylene group, an aliphatic hydrocarbon group containing a ring in the structure, or a divalent linking group containing a hetero atom is preferable. Alternatively, a branched alkylene group or a divalent linking group containing an oxygen atom as a hetero atom is preferable.
As the linear alkylene group, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable.
As the branched alkylene group, an alkylmethylene group or an alkylethylene group is preferable, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — is particularly preferable.
The divalent linking group containing an oxygen atom is preferably a divalent linking group containing an ether bond or an ester bond, and the above-described —Y ²¹ —O—Y ²² —, — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is more preferable. Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, and m ′ is an integer of 0 to 3. Among them, —Y ²¹ —O—C (═O) —Y ²² — is preferable, and a group represented by — (CH ₂ ) _c —O—C (═O) — (CH ₂ ) _d — is particularly preferable. . c is an integer of 1 to 5, and 1 or 2 is preferable. d is an integer of 1-5, and 1 or 2 is preferable.

As the structural unit (a2 ^S ), a structural unit represented by general formula (a2-0-11) or (a2-0-12) shown below is particularly desirable, and represented by formula (a2-0-12). A structural unit is more preferable.

［式中、Ｒ、Ａ’、Ｒ^２６、Ｒ^２７、ｚおよびＲ^３０はそれぞれ前記と同じである。］

[Wherein, R, A ′, R ²⁶ , R ²⁷ , z and R ³⁰ are the same as defined above. ]

In formula (a2-0-11), A ′ is preferably a methylene group, an oxygen atom (—O—) or a sulfur atom (—S—).
R ³⁰ is preferably a linear or branched alkylene group or a divalent linking group containing an oxygen atom. As the linear or branched alkylene group and the divalent linking group containing an oxygen atom in R ^30, the linear or branched alkylene group mentioned above and a divalent linking group containing an oxygen atom are mentioned. Examples are the same as the linking group.
As the structural unit represented by the formula (a2-0-12), a structural unit represented by the following general formula (a2-0-12a) or (a2-0-12b) is particularly preferable.

［式中、Ｒ、Ｒ^２６およびＡ’はそれぞれ前記と同じであり、ｃ〜ｅはそれぞれ独立に１〜３の整数である。］

[Wherein, R, R ²⁶ and A ′ are the same as defined above, and c to e each independently represent an integer of 1 to 3. ]

... Structural unit (a2 ^L ):
Examples of the structural unit (a2 ^L ) include those obtained by substituting R ²⁸ in the general formula (a2-0) with a lactone-containing cyclic group, and more specifically, the following general formula (a2- The structural unit represented by 1)-(a2-5) is mentioned.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；Ｒ’はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基であり；Ｒ^２９は単結合または２価の連結基であり、ｓ”は０〜２の整数であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり；ｍは０または１である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; R ′ is independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogenated alkyl group; , Hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, R ″ is a hydrogen atom or an alkyl group; R ²⁹ is a single bond or a divalent linking group; s ″ is an integer of 0 to 2; A ″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom; m is 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as described above.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ′, the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted.
R ′ is preferably a hydrogen atom in view of industrial availability.
The alkyl group in R ″ may be linear, branched or cyclic.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
Examples of A ″ include the same as A ′ in the general formula (3-1). A ″ represents an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (— S-) is preferable, and an alkylene group having 1 to 5 carbon atoms or -O- is more preferable. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or dimethylmethylene group, and most preferably a methylene group.
R ²⁹ is the same as ^{R 29} in the aforementioned general formula (a2-0).
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a2 ^L ), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formula (a2-1) to More preferably, at least one selected from the group consisting of structural units represented by (a2-3) is selected from the group consisting of structural units represented by the general formula (a2-1) or (a2-3) Particularly preferred is at least one of the above.
Among them, the formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-7), (a2-2-12), (a2-2-2-) 13), (a2-2-15), (a2-3-1) and at least one selected from the group consisting of structural units represented by (a2-3-5) are preferred.

Moreover, as the structural unit (a2 ^L ), a structural unit represented by the following formula (a2-6) or (a2-7) is also preferable.

［式中、Ｒ、Ｒ^２９は前記同様である。］

[Wherein, R and R ²⁹ are the same as defined above. ]

When the component (A1) has the structural unit (a2), the structural unit (a2) may be one type or two or more types. For example, as the structural unit (a2), only the structural unit (a2 ^S ) may be used, only the structural unit (a2 ^L ) may be used, or these may be used in combination. As the structural unit (a2 ^S ) or the structural unit (a2 ^L ), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a2) is preferably 1 to 80 mol% and more preferably 10 to 70 mol% with respect to all the structural units constituting the component (A1). It is preferably 10 to 65 mol%, more preferably 10 to 60 mol%.
By setting the proportion of the structural unit (a2) to be equal to or higher than the lower limit value, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting the ratio to the upper limit value or less, a balance with other structural units is obtained. And various lithographic properties and pattern shapes are good.

..Structural unit (a4)
The component (A1) may further have a structural unit (a4) containing an acid non-dissociable cyclic group as necessary. When the component (A1) has the structural unit (a4), the dry etching resistance of the formed resist pattern is improved. Moreover, the hydrophobicity of (A1) component increases. The improvement in hydrophobicity contributes to the improvement in resolution, resist pattern shape, etc., particularly in the case of development with an organic developer.
The “acid non-dissociable cyclic group” in the structural unit (a4) means that when an acid is generated from the later-described component (B) or the like by exposure, it remains in the structural unit as it is without dissociation even when the acid acts. The cyclic group remaining in
As the structural unit (a4), a structural unit obtained by substituting the acid dissociable group in the structural unit (a1) with an acid non-dissociable cyclic group can be given. Among them, a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and including a non-acid-dissociable aliphatic cyclic group ( a41), a structural unit derived from styrene in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and the hydrogen atom bonded to the carbon atom at the α-position is substituted with a substituent The structural unit (a43) derived from vinyl naphthalene which may be present is preferred.

As the non-acid dissociable aliphatic cyclic group in the structural unit (a41), for example, an atom adjacent to the aliphatic cyclic group (for example, —O— in —C (═O) —O—) is bonded. A monovalent aliphatic cyclic group in which a substituent (atom or group other than a hydrogen atom) is not bonded to a carbon atom, one of the hydrogen atoms of a primary or secondary alkyl group is a monovalent aliphatic cyclic group And a group substituted with a group.
The monovalent aliphatic cyclic group is not particularly limited as long as it is non-acid dissociable, and is used as a resin component of a resist composition such as for ArF excimer laser and for KrF excimer laser (preferably for ArF excimer laser). Many known in the art can be used. The aliphatic cyclic group may be saturated, unsaturated, or saturated.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (= O).
The basic ring structure excluding the substituent of the aliphatic cyclic group is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic cyclic group, those having 3 to 30 carbon atoms are preferable, those having 5 to 30 are more preferable, 5 to 20 are more preferable, 6 to 15 are particularly preferable, and 6 to 12 is most preferable. .
The aliphatic cyclic group may be monocyclic or polycyclic. As the monocyclic aliphatic cyclic group, a group in which one or more hydrogen atoms have been removed from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclobutane, cyclopentane, and cyclohexane. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like. Moreover, a part of carbon atoms constituting the ring of these aliphatic cyclic groups may be substituted with an ether group (—O—).
The aliphatic cyclic group is preferably polycyclic because it is excellent in the above effects. In particular, those having 2 to 4 rings are preferable, and among them, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group and a norbornyl group is preferable in terms of industrial availability. .

Specific examples of the monovalent aliphatic cyclic group as the non-acid-dissociable aliphatic cyclic group include, for example, an atom adjacent to the aliphatic cyclic group (for example, in —C (═O) —O—). A monovalent aliphatic cyclic group in which a substituent (an atom or group other than a hydrogen atom) is not bonded to a carbon atom bonded to —O—). Specifically, a group in which R ¹⁴ in the groups represented by formulas (1-1) to (1-9) given in the description of the acid dissociable group is substituted with a hydrogen atom; a carbon atom constituting the ring skeleton And a group obtained by removing a hydrogen atom from the tertiary carbon atom of a cycloalkane having a tertiary carbon atom formed only by the above.
Examples of the group in which one hydrogen atom of the primary or secondary alkyl group is substituted with a monovalent aliphatic cyclic group include those represented by the formulas (2-1) to (2- And a group in which at least one of R ^{15 and} R ^{16 in} 6) is a hydrogen atom.

... Structural unit (a41):
As the structural unit (a41), structural units in which the acid dissociable group in the structural unit (a11) is substituted with an acid non-dissociable aliphatic cyclic group can be mentioned, and in the general formula (a1-0-1), A structural unit in which X ¹ is substituted with a non-acid-dissociable aliphatic polycyclic group, that is, a structural unit represented by the following general formula (a4-1-1) is preferred, and in particular, the following general formula (a4-1-1- The structural units represented by 11) to (a4-1-15) are preferred.

［式中、Ｒは前記と同じであり、Ｒ^４０は酸非解離性の脂肪族多環式基である。］

[Wherein, R is the same as defined above, and R ⁴⁰ represents a non-acid-dissociable aliphatic polycyclic group. ]

... Structural unit (a42), structural unit (a43):
The structural unit (a42) derived from styrene in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent has the hydrogen atom bonded to the carbon atom at the α-position substituted with a substituent. The hydrogen atom bonded to the benzene ring may be substituted with a substituent.
In the structural unit (a43) derived from vinylnaphthalene in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, the hydrogen atom bonded to the α-position carbon atom is substituted with the substituent. The hydrogen atom bonded to the naphthalene ring may be substituted with a substituent.
Examples of the substituent include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and a halogenated alkyl group having 1 to 5 carbon 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.

When the component (A1) has the structural unit (a4), the structural unit (a4) may be one kind or two or more kinds.
In the component (A1), the proportion of the structural unit (a4) is preferably from 1 to 30 mol%, more preferably from 1 to 20 mol%, more preferably from 5 to 20 mol, based on all structural units constituting the component (A1). % Is more preferable.
By setting the proportion of the structural unit (a4) to be equal to or higher than the lower limit value, the effect of containing the structural unit (a4) can be sufficiently obtained, and by setting the ratio to the upper limit value or lower, a balance with other structural units is obtained. be able to.

In the resist composition of the present invention, the component (A) preferably has a carboxy group as an acidic group.
In this case, as a suitable component (A), a polymer compound having a structural unit (a5) containing a carboxy group as an acidic group (hereinafter, this polymer compound is referred to as “component (A1-1)”) can be mentioned. It is done.
Specifically, as the component (A1-1), a copolymer composed of the structural unit (a5) and the structural unit (a2), the structural unit (a5), the structural unit (a1), and the structural unit (a2) And a copolymer.

In the resist composition of the present invention, the component (A) preferably has a phenolic hydroxyl group as an acidic group.
In this case, as a suitable component (A), a polymer compound having a structural unit (a5) containing a phenolic hydroxyl group as an acidic group (hereinafter, this polymer compound is referred to as “component (A1-2)”). Can be mentioned.
Specific examples of the component (A1-2) include a polymer (homopolymer) composed of the structural unit (a5).

  Moreover, in the resist composition of this invention, (A) component which does not contain the structure decomposed | disassembled by the effect | action of an acid can be used. That is, according to the resist composition of the present invention, unlike the conventional case, the resist composition does not undergo a decomposition reaction due to exposure of the acid-decomposable group in the substrate component, that is, the polarity of the substrate component does not change by exposure. A pattern can be formed. As the component (A), it is preferable to use the component (A1-2).

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography (GPC)) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, and 2000 to 2000 20000 is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
The dispersity (Mw / Mn) of the component (A1) is not particularly limited, but is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5. . In addition, Mn shows a number average molecular weight.

The component (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
As the monomer for deriving each structural unit, a commercially available monomer may be used, or a monomer synthesized using a known method may be used.

In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the component (A) is more preferably 50% by mass or more, further preferably 75% by mass or more, and may be 100% by mass with respect to the total mass of the component (A). When the proportion is 50% by mass or more, an association structure with the component (C) is easily formed, and the resist film can be more stably formed.

(A) A component may contain base-material components (henceforth "(A2) component") other than (A1) component in the range which does not impair the effect of this invention. The component (A2) is not particularly limited, and conventionally proposed resins and low molecular compounds can be used.
In the resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

[Compound (C)]
The compound (C) in the present invention may be any compound that can form an association structure with the acidic group in the component (A), and among them, a basic compound is preferable.
The basic compound is not particularly limited, and has been proposed as an acid diffusion control agent for a chemically amplified resist, that is, acts as a quencher for trapping acid generated from the component (B) by exposure. Can be used.
The “basic compound” as used herein refers to a compound that is relatively basic with respect to the component (A) and the component (B) described later.
The component (C) may be a basic compound (C1) composed of a cation moiety and an anion moiety (hereinafter referred to as “(C1) component”), and a basic compound (C2) that does not correspond to the component (C1). (Hereinafter referred to as “component (C2)”).

-Component (C1) As the component (C1), the compound (c1-1) represented by the following general formula (c1-1) (hereinafter referred to as "(c1-1) component"), the following general formula (c1- 2) (c1-2) (hereinafter referred to as “component (c1-2)”) and compound (c1-3) represented by the following general formula (c1-3) (hereinafter “(c1- 3) It is preferably at least one selected from the group consisting of “component”.

［式中、Ｒ^４は置換基を有していてもよい炭化水素基であり、Ｚ^２ｃは置換基を有していてもよい炭素数１〜３０の炭化水素基（ただし、Ｓに隣接する炭素にはフッ素原子は置換されていないものとする）であり、Ｒ^５は有機基であり、Ｙ^５は直鎖状、分岐鎖状若しくは環状のアルキレン基またはアリーレン基であり、Ｒｆ^３はフッ素原子を含む炭化水素基であり、Ｍ^＋はそれぞれ独立にスルホニウム又はヨードニウムカチオンである。］

[Wherein, R ⁴ is a hydrocarbon group which may have a substituent, and Z ^2c is a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent (however, adjacent to S R ⁵ is an organic group, Y ⁵ is a linear, branched or cyclic alkylene group or an arylene group, and Rf ³ is fluorine. It is a hydrocarbon group containing an atom, and each M ⁺ is independently a sulfonium or iodonium cation. ]

-(C1-1) component.
... Anion moiety In formula (c1-1), R ⁴ is a hydrocarbon group which may have a substituent.
The hydrocarbon group which may have a substituent for R ⁴ may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group in the hydrocarbon group for R ^{4 is} a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group 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. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group in the hydrocarbon group for R ⁴ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In R ⁴ , the aliphatic hydrocarbon group may be a group in which a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, and hydrogen constituting the aliphatic hydrocarbon group A part or all of the atoms may be substituted with a substituent containing a hetero atom.
The “heteroatom” in R ⁴ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include groups represented by the following formulas (L1) to (L6) and (S1) to (S4), respectively.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, wherein R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, each of the alkylene groups in Q ″, R ⁹⁴ and R ⁹⁵ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, preferably 1 to 5 carbon atoms. More preferably, 1 to 3 is particularly preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —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) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —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 the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.

In the aliphatic cyclic group, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

Among them, the hydrocarbon group which may have a substituent of R ⁴ is an aromatic hydrocarbon group which may have a substituent, or an aliphatic cyclic group which may have a substituent. A phenyl group or naphthyl group which may have a substituent; one or more hydrogen atoms are removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. More preferably, it is a group.

In addition, the hydrocarbon group which may have a substituent for R ⁴ is preferably a linear or branched alkyl group or a fluorinated alkyl group.
The number of carbon atoms of the linear or branched alkyl group of R ⁴ is preferably 1 to 10, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, Linear alkyl group such as heptyl group, octyl group, nonyl group, decyl group, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3- Examples thereof include branched alkyl groups such as methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, and 4-methylpentyl group.

The fluorinated alkyl group for R ⁴ may be linear or cyclic, but is preferably linear or branched.
1-11 are preferable, as for carbon number of a fluorinated alkyl group, 1-8 are more preferable, and 1-4 are more preferable. Specifically, for example, a part or all of a linear alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc. Or a branched chain such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, or a 3-methylbutyl group. And a group in which some or all of the hydrogen atoms constituting the alkyl group are substituted with fluorine atoms.
Moreover, the fluorinated alkyl group for R ⁴ may contain an atom other than a fluorine atom. Examples of atoms other than fluorine atoms include oxygen atoms, carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Among them, the fluorinated alkyl group for R ⁴ is preferably a group in which some or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms. It is preferable that all the hydrogen atoms which comprise are the group (perfluoroalkyl group) substituted by the fluorine atom.

In the present specification and claims, the “acid dissociation constant (pKa)” is an index indicating the acid strength of the target substance. The pKa of the acid generated from the component (C1) or the component (B) by exposure is calculated by a known method such as “ACD / Labs” (trade name, manufactured by Advanced Chemistry Development) by a conventional method. Can be sought.
Preferred specific examples of the anion moiety of the component (c1-1) are shown below. The pKa shown together with the specific example is a value calculated by performing a simulation using the software “ACD / Labs” except for the anion (actual measurement) represented by the formula (c1-1-1).
In addition, about pKa shown with the specific example of this anion part, like the case of the anion represented by the following formula (c1-1-1)-(c1-1-3), an electron withdrawing part (trifluoromethyl group) When the introduction site of α is lowered to α, β, γ, the value of pKa tends to decrease (acid strength increases); the following formulas (c1-1-2) and (c1-1-4) When an oxygen atom is introduced into the β-position as in the case of the anion produced, the pKa value tends to be small; represented by the following formulas (c1-1-1), (c1-1-5), etc. If there is no electron withdrawing site as in the case of anions, the pKa value tends to increase.

... Cation part In formula (c1-1), M ⁺ is an organic cation.
Although it does not specifically limit as an organic cation of M ^<+> , For example, what is represented by the following general formula (b-c1) or general formula (b-c2) is mentioned.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”はそれぞれ独立に置換基を有していてもよいアリール基、アルキル基又はアルケニル基を表す。式（ｂ−ｃ１）におけるＲ^１”〜Ｒ^３”のうち、いずれか二つが相互に結合して式中のイオウ原子と共に環を形成してもよい。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent. Any two of R ¹ ″ to R ³ ″ in formula (b-c1) may be bonded to each other to form a ring together with the sulfur atom in the formula. ]

In formula (b-c1), R ¹ ″ to R ³ ″ each independently represents an aryl group, alkyl group or alkenyl group which may have a substituent. Any two of R ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula.

As the aryl group for R ¹ ″ to R ³ ″, an unsubstituted aryl group having 6 to 20 carbon atoms; some or all of the hydrogen atoms of the unsubstituted aryl group are alkyl groups, alkoxy groups, halogen atoms, hydroxyl groups , An oxo group (═O), an aryl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C (═O) —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O And a substituted aryl group substituted with —R ⁸ ′ and the like. R ⁶ ′, R ⁷ ′ and R ⁸ ′ are each a linear, branched or cyclic saturated hydrocarbon group having 1 to 25 carbon atoms, or a C 2 to 5 carbon atoms. It is a linear or branched aliphatic unsaturated hydrocarbon group.
In R ¹ ″ to R ³ ″, the unsubstituted aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group as a substituent in the substituted aryl group of R ¹ ″ to R ³ ″ is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Most preferably.
As the alkoxy group as a substituent in the substituted aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group. Most preferably it is.
The halogen atom as a substituent in the substituted aryl group is preferably a fluorine atom.
Examples of the aryl group as a substituent in the substituted aryl group include the same aryl groups as those described above for R ¹ ″ to R ³ ″.

As the alkoxyalkyloxy group in the substituted aryl group, for example,
General formula: -O-C ( ^R47 ) ( ^R48 ) -O- ^R49
[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group. ] Is represented.
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
At least one of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom. In particular, it is more preferable that one is a hydrogen atom and the other is a hydrogen atom or a methyl group.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

As the alkoxycarbonylalkyloxy group in the substituted aryl group, for example,
General formula: —O—R ⁵⁰ —C (═O) —O—R ⁵⁶
[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵⁶ represents a tertiary alkyl group. ] Is represented.
The linear or branched alkylene group for R ⁵⁰ preferably has 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, or a 1,1-dimethylethylene group. Etc.
As the tertiary alkyl group for R ⁵⁶ , 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-methyl -1-cyclohexyl group, 1-ethyl-1-cyclohexyl group, 1- (1-adamantyl) -1-methylethyl group, 1- (1-adamantyl) -1-methylpropyl group, 1- (1-adamantyl) -1-methylbutyl group, 1- (1-adamantyl) -1-methylpentyl group; 1- (1-cyclopentyl) -1-methylethyl group, 1- (1-cyclopentyl) -1-methylpropyl group, 1- (1-cyclopentyl) -1-methylbutyl group, 1- (1-cyclopentyl) -1-methylpentyl group; 1- (1-cyclohexyl) -1-methylethyl Group, 1- (1-cyclohexyl) -1-methylpropyl group, 1- (1-cyclohexyl) -1-methylbutyl group, 1- (1-cyclohexyl) -1-methylpentyl group, tert-butyl group, tert -Pentyl group, tert-hexyl group and the like.
Furthermore, the general ^formula: the ^{R 56} in the -O-R 50 -C (= O ) -O-R 56, also include groups replaced by ^{R 56} '. R ⁵⁶ ′ is a hydrogen atom, an alkyl group, a fluorinated alkyl group, or an aliphatic cyclic group that may contain a hetero atom.
^Examples of the alkyl group for R ⁵⁶ ′ include the same alkyl groups as those described above for R ⁴⁹ .
^Examples of the fluorinated alkyl group for R ⁵⁶ ′ include groups in which some or all of the hydrogen atoms within the alkyl group for R ⁴⁹ have been substituted with fluorine atoms.
Examples of the aliphatic cyclic group which may contain a hetero atom in R ⁵⁶ ′ include an aliphatic cyclic group containing no hetero atom, an aliphatic cyclic group containing a hetero atom in the ring structure, and an aliphatic cyclic group. Examples include those in which a hydrogen atom in the group is substituted with a heteroatom.
Regarding R ⁵⁶ ′, the aliphatic cyclic group containing no hetero atom includes a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Can be mentioned. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
Specific examples of the aliphatic cyclic group containing a hetero atom in the ring structure for R ⁵⁶ ′ include groups represented by the aforementioned formulas (L1) to (L6) and (S1) to (S4), respectively. Can be mentioned.
As for R ⁵⁶ ′, the hydrogen atom in the aliphatic cyclic group is specifically substituted with a hetero atom, specifically, the hydrogen atom in the aliphatic cyclic group is substituted with an oxygen atom (═O), etc. Is mentioned.

^{-C (= O) -O-R} 6 ', -O-C (= O) -R 7', 'R 6 ^{in' -O-R 8, R 7} ', R 8' are each carbon atoms 1 to 25 linear, branched or cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a linear or branched aliphatic unsaturated hydrocarbon group having 2 to 5 carbon atoms. .
The linear or branched saturated hydrocarbon group has 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, and more preferably 4 to 10 carbon atoms.
Examples of the linear saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.
Examples of the branched saturated hydrocarbon group excluding the tertiary alkyl group include, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3 -Methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like can be mentioned.
The linear or branched saturated hydrocarbon group may have a substituent. Examples of the substituent include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), a cyano group, and a carboxy group.
As the alkoxy group as a substituent of the linear or branched saturated hydrocarbon group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, An n-butoxy group and a tert-butoxy group are preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent of the linear or branched saturated hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
As the halogenated alkyl group as a substituent of the linear or branched saturated hydrocarbon group, part or all of the hydrogen atoms of the linear or branched saturated hydrocarbon group are the halogen atoms. And a group substituted with.
The cyclic saturated hydrocarbon group having 3 to 20 carbon atoms in R ⁶ ′, R ⁷ ′, and R ⁸ ′ may be either a polycyclic group or a monocyclic group. A group in which one hydrogen atom has been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, and the like. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Group and the like.
The cyclic saturated hydrocarbon group may have a substituent. For example, part of the carbon atoms constituting the ring of the cyclic alkyl group may be substituted with a heteroatom, or the hydrogen atom bonded to the ring of the cyclic alkyl group may be substituted with a substituent. Good.
Examples of the former include one or more hydrogen atoms from a heterocycloalkane in which a part of the carbon atoms constituting the ring of the monocycloalkane or polycycloalkane is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Examples include groups other than atoms. The ring structure may have an ester bond (—C (═O) —O—). Specifically, a lactone-containing monocyclic group such as a group obtained by removing one hydrogen atom from γ-butyrolactone, or a group obtained by removing one hydrogen atom from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring. And other lactone-containing polycyclic groups.
Examples of the substituent in the latter example include the same as those described above as the substituent that the linear or branched alkyl group may have, a lower alkyl group, and the like.
R ⁶ ′, R ⁷ ′, and R ⁸ ′ may be a combination of a linear or branched alkyl group and a cyclic alkyl group.
A combination of a linear or branched alkyl group and a cyclic alkyl group includes a group in which a cyclic alkyl group is bonded as a substituent to a linear or branched alkyl group, and a substituent to the cyclic alkyl group. And a group having a linear or branched alkyl group bonded thereto.
Examples of the linear aliphatic unsaturated hydrocarbon group for R ⁶ ′, R ⁷ ′, and R ⁸ ′ include a vinyl group, a propenyl group (allyl group), and a butynyl group.
Examples of the branched aliphatic unsaturated hydrocarbon group for R ⁶ ′, R ⁷ ′, and R ⁸ ′ include a 1-methylpropenyl group and a 2-methylpropenyl group.
The linear or branched aliphatic unsaturated hydrocarbon group may have a substituent. Examples of the substituent include the same ones as those exemplified as the substituent which the linear or branched alkyl group may have.
Among R ⁷ ′ and R ⁸ ′, among them, the lithography characteristics and the resist pattern shape are good, so that the linear or branched saturated hydrocarbon group having 1 to 15 carbon atoms, or the carbon number 3-20 cyclic saturated hydrocarbon groups are preferred.

Examples of the alkyl group for R ¹ ″ to R ³ ″ include a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. Especially, it is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.

As an alkenyl group of R < ¹ >"-R< ³ >", it is preferable that it is C2-C10, for example, 2-5 are more preferable, and 2-4 are more preferable. Specific examples include a vinyl group, a propenyl group (allyl group), a butynyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group.

When any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula, it is preferable that a 3 to 10 membered ring including the sulfur atom is formed, It is particularly preferable to form a 5- to 7-membered ring.

  Specific examples of the cation moiety in the compound represented by the formula (b-c1) include those shown below.

［式中、ｇ１は繰返し数を示し、１〜５の整数である。］

[Wherein g1 represents the number of repetitions and is an integer of 1 to 5. ]

［式中、ｇ２、ｇ３は繰返し数を示し、ｇ２は０〜２０の整数であり、ｇ３は０〜２０の整数である。］

[Wherein g2 and g3 represent the number of repetitions, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

In the formula (b-c2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Examples of the alkenyl group for R ⁵ ″ to R ⁶ ″ include the same alkenyl groups for R ¹ ″ to R ³ ″.
Specific examples of the cation moiety in the compound represented by the formula (b-c2) include diphenyliodonium and bis (4-tert-butylphenyl) iodonium.

Examples of the organic cation of M ⁺ in the formula (c1-1) include those represented by the following general formula (b-5) or (b-6).

［式中、Ｒ^８１〜Ｒ^８６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{81 to} R ⁸⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{81 to} R ⁸⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{81 to} R ⁸⁶ are integers of 2 or more, the plurality of R ^{81 to} R ⁸⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

  Preferable examples of the cation represented by the formula (b-5) or the formula (b-6) include those shown below.

Furthermore, examples of the organic cation of M ⁺ in the formula (c1-1) include those represented by the following general formula (b-7) or general formula (b-8).

In formulas (b-7) and (b-8), R ⁹ and R ¹⁰ are each independently a phenyl group, a naphthyl group, or an alkyl group having 1 to 5 carbon atoms, alkoxy, which may have a substituent. Group, hydroxyl group. Examples of the substituent include a substituent in the substituted aryl group exemplified in the description of the aryl group of R ¹ ″ to R ³ ″ (an alkyl group, an alkoxy group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, a halogen atom). Atom, hydroxyl group, oxo group (═O), aryl group, —C (═O) —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O—R ⁸ ′, the above general formula ^{: -O-R 50 -C (=} O) based on ^{R 56} is replaced by ^{R 56} 'in the ^{-O-R 56,} etc.) to be similar.
R ⁴ ′ is an alkylene group having 1 to 5 carbon atoms.
u is an integer of 1 to 3, and 1 or 2 is most preferable.
Preferable examples of the cation represented by the formula (b-7) or the formula (b-8) include those shown below.
In the formula shown below, R ^C represents the substituents exemplified in the description of the substituted aryl group (alkyl group, alkoxy group, alkoxyalkyloxy group, alkoxycarbonylalkyloxy group, halogen atom, hydroxyl group, oxo group ( ═O), aryl group, —C (═O) —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O—R ⁸ ′).

  As the component (c1-1), one type may be used alone, or two or more types may be used in combination.

-(C1-2) component.
... Anion moiety In formula (c1-2), Z ^2c is a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.
The hydrocarbon group having 1 to 30 carbon atoms which may have a substituent of Z ^2c may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the above formula (c1-1) those in the same manner as R ⁴ of the like.
Among them, the hydrocarbon group which may have a substituent of Z ^2c is preferably an aliphatic cyclic group which may have a substituent, adamantane, norbornane, isobornane, tricyclodecane, It is more preferably a group obtained by removing one or more hydrogen atoms from tetracyclododecane, camphor or the like (which may have a substituent).
The hydrocarbon group for Z ^2c may have a substituent, and examples of the substituent include the same as the substituents for the hydrocarbon group for R ⁴ in formula (c1-1). However, in Z ^2c , the carbon adjacent to the S atom in SO ₃ ^— is not fluorine-substituted. When SO ₃ ^— and a fluorine atom are not adjacent to each other, the anion of the component (c1-2) becomes an appropriate weak acid anion, and the quenching ability of the component (C) is improved.
Preferred specific examples of the anion moiety of the component (c1-2) are shown below. The pKa shown together with a specific example is a value calculated by performing a simulation using the software “ACD / Labs”.

During ... Cation formula (c1-2), ^{M +} is the same as ^{M +} in the formula (c1-1).
As the component (c1-2), one type may be used alone, or two or more types may be used in combination.

-(C1-3) component.
... Anion moiety In formula (c1-3), R ⁵ represents an organic group.
The organic group for R ⁵ is not particularly limited, but is an alkyl group, an alkoxy group, —O—C (═O) —C (R ^C2 ) ═CH ₂ (R ^C2 is a hydrogen atom, a carbon number of 1 to 5 is an alkyl group of 5 or a halogenated alkyl group having 1 to 5 carbon atoms), or —O—C (═O) —R ^C3 (R ^C3 is a hydrocarbon group).
The alkyl group of R ⁵ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A part of hydrogen atoms of the alkyl group represented by R ⁵ may be substituted with a hydroxyl group, a cyano group, or the like.
The alkoxy group of R ⁵ is preferably an alkoxy group having 1 to 5 carbon atoms. Specific examples of the alkoxy group having 1 to 5 carbon atoms include methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n- Examples include butoxy group and tert-butoxy group. Of these, a methoxy group and an ethoxy group are most preferable.

When R ⁵ is —O—C (═O) —C (R ^C2 ) ═CH ₂ , R ^C2 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. is there.
The alkyl group having 1 to 5 carbon atoms in R ^C2 is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, n -Butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like can be mentioned.
The halogenated alkyl group in R ^C2 is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom. 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.
R ^C2 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a fluorinated alkyl group having 1 to 3 carbon atoms, and is most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

When R ⁵ is —O—C (═O) —R ^C3 , R ^C3 is a hydrocarbon group.
The hydrocarbon group for R ^C3 may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. Specific examples of the hydrocarbon group for R ^C3 include the same groups as those described above for R ⁴ in formula (c1-1).
Among them, as the hydrocarbon group of R ^C3 , an alicyclic group in which one or more hydrogen atoms are removed from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like, Aromatic groups such as phenyl group and naphthyl group are preferred. When R ^C3 is an alicyclic group, the resist composition is well dissolved in an organic solvent, so that the lithography properties are improved. Further, when R ^C3 is an aromatic group, in lithography using EUV or the like as an exposure light source, the resist composition is excellent in light absorption efficiency, and sensitivity and lithography characteristics are good.

Among them, as R ⁵ , —O—C (═O) —C (R ^C2 ′) ═CH ₂ (R ^C2 ′ is a hydrogen atom or a methyl group), or —O—C (═O ) -R ^C3 ′ (R ^C3 ′ is an aliphatic cyclic group).

In formula (c1-3), Y ⁵ represents a linear, branched, or cyclic alkylene group or an arylene group.
As the linear, branched or cyclic alkylene group or arylene group for Y ⁵ , among the divalent linking groups for Y ^{2 in} the above formula (a1-0-2), “linear or branched chain” And the same as the “cyclic aliphatic hydrocarbon group”, “cyclic aliphatic hydrocarbon group”, and “aromatic hydrocarbon group”.
Among these, Y ⁵ is preferably an alkylene group, more preferably a linear or branched alkylene group, and even more preferably a methylene group or an ethylene group.

In formula (c1-3), Rf ³ represents a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom of Rf ³ is preferably a fluorinated alkyl group, and more preferably the same as the fluorinated alkyl group of R ⁴ above.
The preferable specific example of the anion part of (c1-3) component is shown below. The pKa shown together with a specific example is a value calculated by performing a simulation using the software “ACD / Labs”.

During ... Cation formula (c1-3), ^{M +} is the same as ^{M +} in the formula (c1-1).
As the component (c1-3), one type may be used alone, or two or more types may be used in combination.

The component (C1) may contain only one of the above components (c1-1) to (c1-3), or may contain two or more. Especially, it is especially preferable to contain (c1-3) component.
The component (C1) is preferably an ionic compound that generates an acid having an acid dissociation constant (pKa) of 0 or more upon exposure, more preferably 0 to 15 pKa, and still more preferably 0 to 10 pKa. In particular, an ionic compound that generates an acid having a pKa of 0 to 5 is preferable.
When an ionic compound that generates an acid having a pKa of 0 or more is used, a salt exchange reaction with the component (B) proceeds favorably by exposure, and a dissolution contrast is easily obtained in an organic developer.
Incidentally, shown as preferable specific examples of the anion portion in the (c1-1) ~ (c1-3) component, carboxylate anion group ^{(-C (= O) O -} ), alkyl sulfonates having no electron withdrawing site Group, aryl sulfonate group having no electron withdrawing site and sulfonylamide anion group (—N ⁻ —SO ₂ —) are sulfonate groups having an electron withdrawing site exemplified in the description of the component (B) described later. Since the acid strength is weaker than (—SO ₃ ^— ) and sulfonylimide anion group (—SO ₂ —N ^—— SO ₂ —), compounds having other exemplified anions as well as pKa written together with some exemplified anions It can be said that pKa generates 0 or more acids.
Among the components (C1), a compound having a cation moiety that has light absorptivity and can be decomposed by exposure is also obtained because the dissolution contrast is more easily obtained with respect to the organic developer and the sensitivity is increased. preferable.

In the resist composition, the content of the component (C1) is preferably 1 to 50 parts by mass, more preferably 2 to 45 parts by mass with respect to 100 parts by mass of the component (A). It is more preferable that it is 40 mass parts, and it is especially preferable that it is 5-30 mass parts.
When the content of the component (C1) is not less than the lower limit of the above range, an association structure with the component (A) is easily formed, and the resist film can be more stably formed. When it is not more than the upper limit of the above range, the sensitivity can be maintained satisfactorily and the throughput is excellent.

(Method for producing components (c1-1) to (c1-3))
The manufacturing method of (c1-1) component and (c1-2) component is not specifically limited, It can manufacture by a well-known method.
If (c1-3) component manufacturing method is not particularly limited, for example, the formula (c1-3) is R ⁵ in a group having an oxygen atom at the terminal which binds to Y ⁵ By reacting the compound (i-1) represented by the following general formula (i-1) with the compound (i-2) represented by the following general formula (i-2), the following general formula ( The compound (i-3) represented by i-3) is obtained, and the compound (i-3) is reacted with Z ⁻ M ⁺ (i-4) having a desired cation M ⁺ to give a general formula The compound (c1-3) represented by (c1-3) is produced.

［式中、Ｒ^５、Ｙ^５、Ｒｆ^３、Ｍ^＋は、それぞれ、前記一般式（ｃ１−３）中のＲ^５、Ｙ^５、Ｒｆ^３、Ｍ^＋と同じである。Ｒ^５ａはＲ^５から末端の酸素原子を除いた基であり、Ｚ⁻は対アニオンである。］

^{Wherein, R 5, Y 5, Rf} 3, M + , respectively, the general formula (c1-3) ^R 5 ^in, Y ^5, Rf 3, is the same as ^{M +.} R ^5a is a group obtained by removing a terminal oxygen atom from R ⁵ , and Z ⁻ is a counter anion. ]

First, compound (i-1) and compound (i-2) are reacted to obtain compound (i-3).
In formula (i-1), R ^5a is a group obtained by removing a terminal oxygen atom from R ⁵ . In formula (i-2), Y ⁵ and Rf ³ are the same as described above.
As compound (i-1) and compound (i-2), commercially available compounds may be used or synthesized.
The method for obtaining compound (i-3) by reacting compound (i-1) with compound (i-2) is not particularly limited. For example, compound (i-) can be obtained in the presence of an appropriate acid catalyst. After reacting 2) and compound (i-1) in an organic solvent, the reaction mixture can be washed and recovered.

The acid catalyst in the said reaction is not specifically limited, For example, toluenesulfonic acid etc. are mentioned, The usage-amount is about 0.05-5 mol with respect to 1 mol of compounds (i-2).
The organic solvent in the above reaction may be any material that can dissolve the compound (i-1) and the compound (i-2) as raw materials, and specifically includes toluene and the like. It is preferable that it is 0.5-100 mass parts with respect to (i-1), and it is more preferable that it is 0.5-20 mass parts. A solvent may be used individually by 1 type and may use 2 or more types together.
The amount of compound (i-2) used in the above reaction is usually preferably about 0.5 to 5 mol, more preferably about 0.8 to 4 mol, per 1 mol of compound (i-1).

The reaction time in the above reaction varies depending on the reactivity between the compound (i-1) and the compound (i-2), the reaction temperature, etc., but is usually preferably 1 to 80 hours, more preferably 3 to 60 hours. .
The reaction temperature in the above reaction is preferably 20 ° C to 200 ° C, more preferably about 20 ° C to 150 ° C.

Next, the obtained compound (i-3) and the compound (i-4) are reacted to obtain the compound (c1-3).
In formula (i-4), M ⁺ is the same as described above, and Z ⁻ is a counter anion.
The method of reacting compound (i-3) and compound (i-4) to obtain compound (c1-3) is not particularly limited, but for example, compound in the presence of a suitable alkali metal hydroxide. It can be carried out by dissolving (i-3) in a suitable organic solvent and water, adding compound (i-4) and reacting with stirring.

The alkali metal hydroxide in the above reaction is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide and the like, and the amount used is 0.3 to 1 mol per 1 mol of compound (i-3). About 3 mol is preferable.
Examples of the organic solvent in the above reaction include solvents such as dichloromethane, chloroform, and ethyl acetate, and the amount used is preferably 0.5 to 100 parts by mass with respect to compound (i-3). More preferably, it is 5-20 mass parts. A solvent may be used individually by 1 type and may use 2 or more types together.
The amount of compound (i-4) used in the above reaction is usually preferably about 0.5 to 5 mol, more preferably about 0.8 to 4 mol, relative to 1 mol of compound (i-3).

The reaction time in the above reaction varies depending on the reactivity between the compound (i-3) and the compound (i-4), the reaction temperature, etc., but is usually preferably 1 to 80 hours, more preferably 3 to 60 hours. .
20-200 degreeC is preferable and, as for the reaction temperature in the said reaction, about 20-150 degreeC is more preferable.
After completion of the reaction, the compound (c1-3) in the reaction solution may be isolated and purified. For isolation and purification, conventionally known methods can be used. For example, concentration, solvent extraction, distillation, crystallization, recrystallization, chromatography, etc. can be used alone or in combination of two or more thereof. it can.

The structure of the compound (c1-3) obtained as described above is as follows: ¹ H-nuclear magnetic resonance (NMR) spectrum method, ¹³ C-NMR spectrum method, ¹⁹ F-NMR spectrum method, infrared absorption (IR) spectrum method. , Mass spectrometry (MS) method, elemental analysis method, X-ray crystal diffraction method, etc.

-Component (C2) The component (C2) is not particularly limited as long as it does not correspond to the component (C1), and examples thereof include amines such as aliphatic amines and aromatic amines. Secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include amines (alkylamines or alkylalcoholamines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 20 or less carbon atoms, cyclic amines, other amines An aliphatic amine etc. are mentioned.

The alkyl group of the alkylamine may be linear, branched or cyclic.
When the alkyl group is linear or branched, the carbon number thereof is more preferably 2-20, and further preferably 2-8.
When the alkyl group is cyclic (when it is a cycloalkyl group), the carbon number is preferably 3 to 30, more preferably 3 to 20, still more preferably 3 to 15, and 4 to 12 carbon atoms. It is particularly preferred that the number of carbon atoms is 5-10. The alkyl group may be monocyclic or polycyclic. Specific examples include groups in which one or more hydrogen atoms have been removed from monocycloalkane, groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as bicycloalkane, tricycloalkane, and tetracycloalkane. . Specific examples of the monocycloalkane include cyclopentane and cyclohexane. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
Examples of the alkyl group in the hydroxyalkyl group possessed by the alkyl alcohol amine include the same alkyl groups as those possessed by the alkyl amine.

Specific examples of the alkylamine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n- Dialkylamines such as heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri- Examples include trialkylamines such as n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, and tri-n-dodecylamine.
Specific examples of the alkyl alcohol amine include diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, tri-n-octanolamine, stearyl diethanolamine, lauryldiethanolamine and the like.
Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.

  Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy Ethoxy) ethoxy} ethyl] amine, triethanolamine triacetate and the like.

  Aromatic amines include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. And carbonylpyrrolidine.

As the component (C2), any one type may be used alone, or two or more types may be used in combination.
Among the components (C2), an alkylamine is preferable because a salt exchange reaction with the component (B) proceeds favorably by exposure and a dissolution contrast is easily obtained with respect to an organic developer, and a trialkylamine is preferable. Is more preferable, and a trialkylamine having 5 to 10 carbon atoms is more preferable.
In the resist composition, the content of the component (C2) is preferably 0.1 to 30 parts by mass and more preferably 0.5 to 25 parts by mass with respect to 100 parts by mass of the component (A). The amount is preferably 1 to 20 parts by mass.
When the content of the component (C2) is not less than the lower limit of the above range, an association structure with the component (A) is easily formed, and the resist film can be formed more stably. When it is not more than the upper limit of the above range, the sensitivity can be maintained satisfactorily and the throughput is excellent.

  As the component (C), one type may be used alone, or two or more types may be used in combination.

[Acid generator component (B)]
The acid generator component (B) in the present invention is an acid generator component that generates an acid having higher strength than the acidic group in the component (A) by exposure.
As such component (B), onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, bisalkyls, which have been proposed as acid generators for chemically amplified resists. Alternatively, diazomethane acid generators such as bisarylsulfonyldiazomethanes and poly (bissulfonyl) diazomethanes, nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, disulfone acid generators and the like.
As such an onium salt-based acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”はそれぞれ独立に置換基を有していてもよいアリール基、アルキル基又はアルケニル基を表す。式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか二つが相互に結合して式中のイオウ原子と共に環を形成してもよい。Ｒ^４”は、置換基を有していてもよいアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent. Any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula. R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.

In the formula (b-1), R ¹ ″ to R ³ ″ each independently has an aryl group which may have a substituent, an alkyl group which may have a substituent, or a substituent. Represents an alkenyl group which may be substituted. Any two of R ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula.
R ¹ ″ to R ³ ″ are an aryl group which may have a substituent in R ¹ ″ to R ³ ″ in the formula (b-c1), an alkyl group which may have a substituent, It is the same as the alkenyl group which may have a substituent.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently has an aryl group which may have a substituent, an alkyl group which may have a substituent, or a substituent. Represents an alkenyl group which may be substituted.
R ⁵ ″ to R ⁶ ″ are an aryl group which may have a substituent in R ⁵ ″ to R ⁶ ″ in the formula (b-c2), an alkyl group which may have a substituent, It is the same as the alkenyl group which may have a substituent.

In formulas (b-1) to (b-2), R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “may have a substituent” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one, or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, a hydroxyl group, a formula: X ³ -Q ^1- [where Q ¹ is a divalent linking group containing an oxygen atom, and X ³ is a substituted group. It is a C3-C30 hydrocarbon group which may have a group. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

In the group represented by X ³ -Q ^1- , Q ¹ is a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) — , R ^{91 to} R ⁹³ are each independently an alkylene group.) And the like.
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —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) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —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 the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond, and in particular, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — or —C (═O) — O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by X ³ -Q ^1- , the hydrocarbon group for X ³ may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group 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. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X ³ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X ³ , the aliphatic hydrocarbon group may be a group in which a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, and hydrogen constituting the aliphatic hydrocarbon group A part or all of the atoms may be substituted with a substituent containing a hetero atom.
The “heteroatom” in X ³ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include groups represented by the aforementioned formulas (L1) to (L6) and (S1) to (S4).

X ^{3 -Q} 1 ^- X 3 in the group represented by is preferably have a substituent cyclic group which may. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is a group obtained by removing one or more hydrogen atoms from the polycycloalkane, and is represented by the aforementioned formulas (L2) to (L6) and (S3) to (S4), respectively. And the like are preferred.

In formulas (b-1) to (b-2), R ⁴ ″ preferably has X ³ -Q ^1- as a substituent. In this case, R ⁴ ″ may be X ³ -Q ¹ -Y. ^10- [wherein Q ¹ and X ³ are the same as above, Y ¹⁰ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted carbon number. 1 to 4 fluorinated alkylene groups. ] Is preferable.
In the group represented by X ³ -Q ¹ -Y ^10- , the alkylene group for Y ¹⁰ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^10, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - _{CH 2 CH 2 CF 2 CF 2} -, - CH (CF 3) CH 2 CH 2 -, - CH 2 CH (CF 3) CH 2 -, - CH (CF 3) CH (CF 3) -, - C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹⁰ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

  Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate (pKa-3.9) or nonafluorobutanesulfonate (pKa-3). .9), bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate (pKa-3.7) or its nonafluorobutanesulfonate (PKa-3.9), tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, dimethyl (4-hydroxy) Naphthyl) sulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, monophenyldimethylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; diphenylmonomethylsulfonium trifluoromethanesulfonate, its Heptafluoropropanesulfonate or its nonafluorobutanesulfonate, (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-tert-butyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, diphenyl (1- (4-methoxy) naphthyl) Sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium Trifluoromethanesulfonate, its heptafluoropropanesulfone 1- (4-methylphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl ) Tetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate; trifluorometa of 1- (4-ethoxynaphthalen-1-yl) tetrahydrothiophenium Sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1 Trifluoromethanesulfonate of phenyltetrahydrothiopyranium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of 1- (4-hydroxyphenyl) tetrahydrothiopyranium, its heptafluoropropanesulfonate or its nonafluorobutane 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothio Examples include trifluoromethane sulfonate of ranium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of 1- (4-methylphenyl) tetrahydrothiopyranium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, etc. .

  Moreover, it is also preferable to use the onium salt which replaced the anion part of these onium salts with the anion represented by either of following formula (b1)-(b9), and among these, an anion part is represented by following formula (b3). It is more preferable to use an onium salt substituted with an anion represented by any one of (b) to (b6).

［式中、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｉは１〜２０の整数であり、Ｒ^７は置換基であり、ｍ１〜ｍ６はそれぞれ独立に０または１であり、ｖ０〜ｖ６はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ６はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[Wherein, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, t3 is an integer of 1 to 3, and r1 to r2 are each independently 0 to 3] I is an integer of 1 to 20, R ⁷ is a substituent, m1 to m6 are each independently 0 or 1, v0 to v6 are each independently an integer of 0 to 3, w1 to w6 are each independently an integer of 0 to 3, and Q ″ is the same as above.]

As the substituent of R ^7, the same as those mentioned as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in the above X ³ Is mentioned.
Code (r1 and r2, W1 to W6) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less This is preferable because the transparency to the surface is improved.
The proportion of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. A perfluoroalkylene group or a perfluoroalkyl group.

In addition, as the onium salt-based acid generator, a sulfonium salt having a cation represented by the general formula (b-5) or (b-6) described above in the cation portion can also be used.
Furthermore, the sulfonium salt which has the cation represented by general formula (b-7) or general formula (b-8) mentioned above in the cation part can also be used.

The anion part of the sulfonium salt having cations represented by the formulas (b-5) to (b-8), respectively, is not particularly limited, and the anion part of the onium salt acid generators proposed so far It may be the same. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ⁴ ″ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion represented by the general formula (b-3) or (b-4), an anion represented by any one of the formulas (b1) to (b9), and the like.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

［式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。］

[In formula (B-1), R ³¹ and R ³² each independently represents an organic group. ]

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with 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. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups as those having no substituent of R ³⁵ .
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope Nthenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [Chemical Formula 18] to [Chemical Formula 19]), International Publication No. 04/074242 (65). The oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on page ˜86 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

As the component (B), one type of acid generator described above may be used alone, or two or more types may be used in combination.
Among these, the component (B) is preferably an ionic compound that generates an acid having an acid dissociation constant (pKa) of less than 0 by exposure, and an ionic compound that generates an acid having a pKa of −1 or less. More preferably. When an ionic compound that generates an acid having a pKa of less than 0 is used, the salt exchange reaction with the component (C) proceeds satisfactorily by exposure, and it becomes easy to obtain a dissolution contrast in an organic developer.
The lower limit of pKa is not particularly limited, but is preferably an ionic compound that generates an acid having a pKa of −15 or more, and more preferably an ionic compound that generates an acid having a pKa of −13 or more.
The sulfonate group (—SO ₃ ^— ) and the sulfonylimide anion group (—SO ₂ —N ^—— SO ₂ —) shown as preferred specific examples of the anion moiety in the onium salt include fluorine serving as an electron withdrawing site. Since the alkylated alkyl groups are adjacent to each other, it can be said that other example compounds generate an acid having a negative value of pKa, similarly to pKa described together with some of the exemplified anions.

In the resist composition, the content of the component (B) is preferably 0.1 to 50 parts by mass and more preferably 0.5 to 45 parts by mass with respect to 100 parts by mass of the component (A). Preferably, it is 1-40 mass parts, More preferably, it is 2-40 mass parts.
When the content of the component (B) is not less than the lower limit of the above range, the salt exchange reaction with the component (C) proceeds sufficiently by exposure. When the amount is not more than the upper limit of the above range, a uniform solution can be obtained when dissolved in an organic solvent, and the storage stability becomes favorable.

[Other ingredients]
If desired, the resist composition of the present invention may further contain miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving coatability, a dissolution inhibitor, a plasticizer. An agent, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

-(S) component The resist composition of the present invention can be produced by dissolving a resist material in an organic solvent (hereinafter sometimes referred to as "(S) component").
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; many such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ether alkyl such as ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having a propylene glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME) among these]; cyclic ethers such as dioxane, methyl lactate, Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, Aromatic organics such as dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene A solvent etc. can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, γ-butyrolactone, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone, and ethyl lactate (EL) are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range. For example, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3. Further, when PGME and cyclohexanone are blended as polar solvents, the mass ratio of PGMEA: (PGME + cyclohexanone) is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2, and even more preferably 3. : 7 to 7: 3.
In addition, as the component (S), PGMEA, EL or a mixed solvent of PGMEA and a polar solvent and a mixed solvent of γ-butyrolactone are also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 1 -20% by mass, preferably 2-15% by mass.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In this example, “pKa (acid dissociation constant)” was calculated by performing simulation using software “ACD / Labs” (trade name, manufactured by Advanced Chemistry Development).

<Negative resist pattern formation>
(Example 1, Comparative Example 1)
Resist compositions were prepared by mixing and dissolving the components shown in Table 1. However, Example 1 is a reference example.

In Table 1, the numerical value in [] is a blending amount (part by mass), and each abbreviation has the following meaning.
(A) -1: a copolymer represented by the following chemical formula (A) -1. Mw 10000, Mw / Mn 1.87. In the chemical formula, the numerical value on the lower right of the structural unit () indicates the proportion (mol%) of the structural unit.
(C) -1: tri-n-octylamine.
(B) -1: (4-methylphenyl) diphenylsulfonium nonafluorobutanesulfonate, pKa-3.9.
(S) -1: Propylene glycol monomethyl ether acetate.

[Contrast evaluation (1)]
Using the resist composition shown in Table 1, a resist pattern was formed as follows, and the contrast was evaluated.
Step (1):
The resist composition of each example was uniformly applied using a spinner on an 8-inch silicon substrate subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 36 seconds, and a baking temperature of 90 ° C. for 60 seconds. A baking process (PAB) was performed to form a resist film (thickness 130 nm).
Step (2):
Next, with respect to the resist film, an exposure apparatus VUVES-4500 (manufactured by RISOTEC JAPAN Co., Ltd.) was used, and the exposure amount was changed within the range of 0.1 to 60.0 mJ / cm ² , and an ArF excimer laser (193 nm) was used. Full exposure was performed.
Step (3):
Next, the exposed resist film was developed at 23 ° C. using butyl acetate for 16 seconds.
The resist film thickness after development was measured using Nanospec 6100A (manufactured by Nanometrics). The result is shown in FIG.

FIG. 5 is a graph (contrast curve) showing changes in the resist film thickness when the exposure amount is changed in Example 1 and Comparative Example 1. In FIG. 5, the vertical axis represents the film thickness (Å) of the developed resist film, and the horizontal axis represents the exposure dose (mJ / cm ² ).
From FIG. 5, in Comparative Example 1, since the film thickness shows a value close to zero regardless of the exposure amount, the resist film is soluble in the developer, and the resist film with respect to the developer before and after the exposure. It can be seen that the solubility has hardly changed.
On the other hand, in Example 1, since the film thickness increases as the exposure amount increases within a certain exposure amount range, it can be seen that the resist film exposed portion is hardly soluble by exposure. That is, it can be seen that a dissolution contrast can be obtained for an organic developer.

<Positive resist pattern formation (1)>
(Examples 2-3, Comparative Examples 2-3)
Each component shown in Table 2 was mixed and dissolved to prepare a resist composition.

In Table 2, numerical values in [] are blending amounts (parts by mass), and each abbreviation has the following meaning.
(A) -2: A homopolymer represented by the following chemical formula (A) -2. Mw7000, Mw / Mn1.12, pKa9.86. In the chemical formula, the numerical value on the lower right of the structural unit () indicates the proportion (mol%) of the structural unit.
(C) -2: a compound represented by the following chemical formula (C) -2, pKa 1.17.
(C) -3: Compound represented by the following chemical formula (C) -3, pKa4.51.
(B) -2: triphenylsulfonium nonafluorobutanesulfonate, pKa-3.9.
(S) -2: Mixed solvent of PGMEA / PGME / cyclohexanone = 45/30/25 (mass ratio).

[Solubility Evaluation for PGMEA / PGME Mixed Solvent (1)]
The mixture of the component (A), the component (C), and the component (B) shown in Table 2 is added to a mixed solvent of PGMEA and PGMEA (PGMEA / PGME (mass ratio) = 6/4), The solubility of the mixture was evaluated.
As a result, in the case of the mixtures in Examples 2 to 3, a cloudy product was formed, and in the case of the mixtures in Comparative Examples 2 to 3, the mixture was dissolved.
The white turbidity produced in the case of the mixtures in Examples 2 to 3 was dissolved by further adding cyclohexanone to form a mixed solvent of PGMEA, PGME and cyclohexanone.
From this, it is considered that the cloudy substance is an association structure of the resin and the compound (C), and the state in which cyclohexanone is added and dissolved is considered to be a state in which the association structure is dissolved in the solution. .

[Contrast evaluation (2)]
Using the resist composition shown in Table 2, a resist pattern was formed as follows, and the contrast was evaluated.
Step (1):
The resist composition of each example was uniformly applied using a spinner on an 8-inch silicon substrate subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 36 seconds, and a baking temperature of 90 ° C. for 60 seconds. Bake treatment (PAB) was performed to form a resist film (film thickness 200 nm).
Step (2):
Next, an exposure apparatus VUVES-4500 (manufactured by RISOTEC Japan Co., Ltd.) is used for the resist film, and the exposure dose is changed within the range of 0.1 to 60.0 mJ / cm ² , and a KrF excimer laser (248 nm). The whole surface exposure was performed.
Step (3):
Next, the exposed resist film was baked (PEB) at a baking temperature of 90 ° C. for 60 seconds, and then developed at 23 ° C. with butyl acetate for 16 seconds.
The resist film thickness after development was measured using Nanospec 6100A (manufactured by Nanometrics). The results are shown in FIGS.

6 to 9 are graphs (contrast curves) showing changes in the resist film thickness when the exposure amount is changed in each of the examples and the comparative examples. In each figure, the vertical axis represents the film thickness (Å) of the developed resist film, and the horizontal axis represents the exposure dose (mJ / cm ² ).
As shown in FIG. 6, in Comparative Example 2, the film thickness is almost zero regardless of the exposure amount. Therefore, the resist film is soluble in the developer, and the solubility of the resist film in the developer before and after the exposure. It can be seen that there has been little change.
From FIG. 7, in Comparative Example 3, since the film thickness is constant with respect to the change in the exposure amount, the resist film is insoluble in the developer, and the solubility of the resist film in the developer almost changes before and after the exposure. You can see that they are not.
From FIG. 8, in Example 2, the film thickness gradually decreased as the exposure amount increased, and the film thickness decreased greatly in the range of 4 to 5 mJ / cm ^2. It is insoluble, and it can be seen that the solubility of the exposed portion of the resist film in the developer is greatly increased at a certain exposure amount.
From FIG. 9, in Example 3, the film thickness gradually decreased as the exposure amount increased, and the film thickness decreased greatly in the range of 6 to 7 mJ / cm ^2. It is insoluble, and it can be seen that the solubility of the exposed portion of the resist film in the developer is greatly increased at a certain exposure amount.
From the above, it can be seen that the resist compositions of Examples 2 and 3 have a dissolution contrast with respect to the organic developer. In addition, it can be seen that Example 2 is more sensitive than Example 3.

<Positive resist pattern formation (2)>
Example 4
Each component shown in Table 3 was mixed and dissolved to prepare a resist composition.

In Table 3, numerical values in [] are blending amounts (parts by mass), and each abbreviation has the following meaning.
(A) -2: A homopolymer represented by the chemical formula (A) -2. Mw7000, Mw / Mn1.12, pKa9.86.
(C) -3: Compound represented by the chemical formula (C) -3, pKa4.51.
(B) -2: triphenylsulfonium nonafluorobutanesulfonate, pKa-3.9.
(S) -2: Mixed solvent of PGMEA / PGME / cyclohexanone = 45/30/25 (mass ratio).

[Solubility Evaluation for PGMEA / PGME Mixed Solvent (2)]
The mixture of the component (A), the component (C) and the component (B) shown in Table 3 was added to a mixed solvent of PGMEA and PGMEA (PGMEA / PGME (mass ratio) = 6/4), The solubility of the mixture was evaluated.
As a result, the mixture in Example 4 produced white turbidity.
The cloudy matter produced in the case of the mixture in Example 4 was dissolved by further adding cyclohexane to form a mixed solvent of PGMEA, PGME and cyclohexane.
From this, it is considered that the cloudy substance is an association structure of the resin and the compound (C), and the state in which cyclohexanone is added and dissolved is considered to be a state in which the association structure is dissolved in the solution. .

[Contrast evaluation (3)]
Using the resist composition shown in Table 3, a resist pattern was formed as follows, and the contrast was evaluated.
Step (1):
The resist composition was uniformly applied using a spinner on an 8-inch silicon substrate subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 36 seconds, and baked at a baking temperature of 90 ° C. for 60 seconds ( PAB) was performed to form a resist film (film thickness 200 nm).
Step (2):
Next, a KrF excimer laser (248 nm) is applied to the resist film with a line width of 200 nm / pitch of 400 nm using a KrF exposure apparatus NSR-S203 (manufactured by Nikon; NA (numerical aperture) = 0.68, OFF LINE). Irradiation was selectively performed through a mask pattern (halftone) targeting line and space.
Step (3):
Next, the exposed resist film was baked (PEB) at a baking temperature of 90 ° C. for 60 seconds, and then developed at 23 ° C. with butyl acetate for 16 seconds.

As a result, when the resist composition of Example 4 was used, a line-and-space positive resist pattern with a line width of 200 nm / pitch of 400 nm was resolved (the optimum exposure at that time was 42 mJ / cm ² ). .

  DESCRIPTION OF SYMBOLS 1 Support body, 2 Resist film, 2a Exposed part, 2b Unexposed part, 3 Photomask

Claims (2)

It possesses an acidic group, the base component containing no decomposing structure under the action of an acid (A), a compound capable of forming the acid group and association structure (C), and an acid dissociation constant (pKa) of less than 0 And using a resist composition containing an acid generator component (B) that generates an acid having higher strength than the acidic group by exposure, the acidic group and the compound (C) are supported on a support. Forming a resist film having an association structure (1);
The resist film is exposed to form a new association structure between the acid generated from the acid generator component (B) and the compound (C) that has formed the association structure, thereby exposing the acidic group. Step (2)
Developing the resist film using a developer containing an organic solvent, and dissolving and removing the exposed portion of the resist film to form a positive resist pattern (3).   The resist pattern formation method of Claim 1 whose said acid generator component (B) is an ionic compound which generate | occur | produces the acid whose acid dissociation constant (pKa) is less than 0 by exposure.

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