JP5764478B2 - Resist pattern forming method - Google Patents

Description

  The present invention relates to a resist pattern forming method for forming a negative resist pattern by developing with an alkaline developer.

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.

  In a positive development process in which a positive chemically amplified resist composition, that is, a chemically amplified resist composition whose solubility in an alkaline developer is increased by exposure and an alkaline developer is combined, as described above, The exposed portion is dissolved and removed with an alkali developer to form a resist pattern. A positive development process that combines a positive chemically amplified resist composition and an alkaline developer is a photomask compared to a negative development process that combines a negative chemically amplified resist composition and an alkaline developer. There are advantages such that the structure can be simplified, sufficient contrast for image formation can be easily obtained, and the characteristics of the pattern to be formed are excellent. 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).

However, with further advancement of lithography technology and expansion of application fields, various lithography characteristics are further improved even in a positive development process combining a positive chemically amplified resist composition and an alkaline developer. Desired.
For example, in the formation of a fine pattern (isolated trench pattern, fine and dense contact hole pattern, etc.), a region having a low optical intensity is generated particularly in the film thickness direction, 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. However, the negative development process is inferior to the positive development process combined with an alkaline developer in terms of environment, apparatus, and cost. On the other hand, a novel resist pattern forming method capable of forming a negative pattern with a high contrast image is required.

In a chemically amplified resist composition, the resist pattern shape and lithography characteristics may be deteriorated due to contamination (environmental influence) on the resist layer of a basic substance such as amine present in the environment. That is, in the chemically amplified resist, due to the reaction mechanism of utilizing the action of acid, the acid is deactivated by the contamination of the basic substance, and the lithography characteristics and pattern shape of the resulting resist pattern are affected. In addition, such environmental influence is also caused by the length of the process delay, for example, the time from the application of the resist to the exposure and the time from the exposure to the post-exposure heating (PEB). The degree differs, and this causes a difference in performance between lots, and changes in sensitivity, shape, resolution, and the like.
In particular, in lithography using an electron beam, EUV, or the like as an exposure light source, exposure is usually performed under a reduced pressure environment, so that a pressure reduction operation or a purge operation needs to be performed, resulting in a long process delay and environmental impact. Becomes a serious problem. Therefore, there is a demand for a resist pattern forming method in which lithography characteristics and pattern shapes are not deteriorated due to environmental influences.
The present invention has been made in view of the above circumstances, and is a novel negative resist pattern forming method that is not easily affected by the environment, and a resist that can be used in the resist pattern forming method and has excellent storage stability. It is an object to provide a composition.

  As a result of intensive studies, the present inventors left an exposed portion of a resist film formed of a resist composition containing a base material component that has increased solubility in an alkaline developer by the action of an acid, Invented a method for forming a negative pattern in which an unexposed portion is dissolved and removed with an “alkaline developer” (Japanese Patent Application No. 2011-106577). The present inventors have found a method capable of suppressing deterioration of the present invention and completed the present invention.

  That is, the resist pattern forming method of the present invention is a resist containing a base component whose solubility in an alkaline developer is increased by the action of an acid, a photobase generator component that generates a base by exposure, and an acidic compound component. A step (1) of applying a composition on a support to form a resist film, a step (2) of forming a protective film by applying a composition for forming a protective film on the resist film, and the resist A step (3) of exposing the film and the protective film, and a baking after the step (3). In the exposed portion of the resist film, the base generated from the photobase generator component by the exposure, and the acid A step (4) of neutralizing the compound component and increasing the solubility of the base material component in an alkaline developer by the action of the acidic compound component in the unexposed portion of the resist film; Resist film was alkali developed, said the step of unexposed portions of the resist film to form a dissolved removed negative resist pattern (5), a resist pattern forming method, which comprises a.

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.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
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.
A “hydroxyalkyl group” is a group in which part or all of the hydrogen atoms of an 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 which can form a fine negative pattern can be provided.

It is a schematic process drawing explaining the example of embodiment of the resist pattern formation method of this invention.

  The resist pattern forming method of the present invention is a resist composition comprising a base component whose solubility in an alkaline developer is increased by the action of an acid, a photobase generator component that generates a base by exposure, and an acidic compound component. (1) for forming a resist film by coating the support on the support, (2) for forming a protective film by applying a protective film-forming composition on the resist film, and the resist film and Step (3) for exposing the protective film, baking after the step (3), and a base generated from the photobase generator component by the exposure in the exposed portion of the resist film, and the acidic compound component And increasing the solubility of the base material component in an alkaline developer by the action of the acidic compound component in the unexposed portion of the resist film, and the resist The alkali development, including, the step (5) to form a negative resist pattern unexposed portion is dissolved and removed of the resist film.

In the present invention, “pre-baking” refers to a heat treatment at 70 ° C. or higher using a hot plate or the like, which is performed after the resist composition is coated on a support and before exposure.
The “negative resist pattern” is a resist pattern in which an unexposed portion of the resist film is dissolved and removed with an alkali developer, and the exposed portion remains as a pattern.
An acidic compound means a compound whose component itself is acidic, that is, a compound that acts as a proton donor.

  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.

FIG. 1 shows an embodiment of the resist pattern forming method of the present invention.
In the present embodiment, a resist composition containing a base material component whose solubility in an alkaline developer is increased by the action of an acid, a photobase generator component that generates a base by exposure, and an acidic compound component is used. .
First, as shown to Fig.1 (a), the said resist composition is apply | coated on the support body 1, and the resist film 2 is formed (process (1); Fig.1 (a)).
Next, the protective film-forming composition is applied on the resist film 2 formed as described above to form the protective film 3 (step (2); FIG. 1 (b)).
Next, as shown in FIG. 1C, the resist film 2 and the protective film 3 formed as described above are exposed through a photomask 4 on which a predetermined pattern is formed. Thereby, in the exposed area | region (exposure part) of the resist film 2, a base generate | occur | produces from a photobase generator component by exposure (process (3); FIG.1 (c)).
After exposure, baking (post-exposure baking (PEB)) is performed. By this baking, in the unexposed portion 2b of the resist film 2, the solubility of the base material component in the alkaline developer is increased by the action of the acidic compound component in the resist film 2. On the other hand, in the exposure part 2a, since the neutralization reaction of the base generated from the photobase generator component by exposure and the acidic compound component in the resist film 2 proceeds, the solubility of the base material component in the alkaline developer is increased. Does not change, or changes even if it changes. As a result, a difference in dissolution rate (dissolution contrast) with respect to the alkaline developer occurs between the exposed portion 2a and the unexposed portion 2b (step (4); FIG. 1 (d)).
Thereafter, development with an alkali 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 alkaline developer. As a result, as shown in FIG. A resist pattern composed of a plurality of resist patterns 2a is formed (step (5); FIG. 1 (e)).

[Step (1)]
In the present embodiment, a resist composition containing a base material component whose solubility in an alkaline developer is increased by the action of an acid, a photobase generator component that generates a base by exposure, and an acidic compound component is supported. A resist film 2 is formed by coating on the body 1.
The resist composition may contain an acid generator component (photo acid generator, thermal acid generator) in addition to the acidic compound component. Either one or both of the thermal acid generator and the photoacid generator may be used in combination.
Specific examples of the resist composition will be described in detail 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. In the multilayer resist method, basically, a method having 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 the resist film and the 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 a material for forming an organic film 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.

The method for applying the resist composition 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 film 2 can be formed by applying the resist composition on the support 1 by a conventionally known method such as using a spinner to form a coating film and drying it.
The resist film 2 can be formed by drying at room temperature on a cooling plate or the like and volatilizing the organic solvent.
As a method for drying the coating film, it is sufficient if the organic solvent (resist solvent) contained in the coating film can be volatilized, and examples thereof include a method of pre-baking (PAB), a method of drying at normal temperature on a cooling plate, and the like. .
The prebake temperature is preferably 70 to 140 ° C, more preferably 70 to 130 ° C, and further preferably 70 to 120 ° C.
The pre-bake time is preferably 40 to 120 seconds, and more preferably 60 to 90 seconds.
Among the above, when prebaking is performed, the organic solvent is easily volatilized even when the resist film thickness is set to a thick film. On the other hand, by drying the resist composition at room temperature and not performing pre-baking, the number of steps of resist pattern formation can be reduced, and the resolution of the resulting resist pattern can be improved.
The presence / absence of pre-baking can 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 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, more preferably 200 nm or less, and 50 to 150 nm or less. It is particularly preferred. If the thickness of the resist film 2 is 300 nm or less, the organic solvent does not easily remain and is easily dried by a coating method such as spin coating at room temperature without performing pre-baking. Internal uniformity is increased.

[Step (2)]
In the present embodiment, a coating film made of a composition for forming a protective film is formed on the resist film 2 formed in the step (1) by using a conventionally known method such as using a spinner and dried. The protective film 3 can be formed. By forming the protective film 3 on the resist film 2, for example, even when the time from the step (1) to the step (3) or (4) is long, the environmental influence is small, and the lithography characteristics and The pattern shape does not deteriorate.
The composition for forming a protective film may contain an acidic compound or an acid generator component (preferably a thermal acid generator).
Specific examples of the protective film-forming composition will be described in detail later.

The application conditions of the protective film forming composition are set according to the thickness (film thickness) of the protective film 3 to be formed.
The thickness of the protective film 3 may be appropriately set depending on the composition of the protective film forming composition, the process delay time in pattern formation, and the like, preferably 10 to 300 nm, more preferably 20 to 200 nm, and still more preferably 30 to 150 nm. It is. By making it within this range, the influence of basic substances such as amines present in the environment on the resist film 2 can be sufficiently suppressed, and a resist pattern having good lithography characteristics and pattern shape can be formed. Can do.

As a drying method of the coating film made of the composition for forming a protective film, it is only necessary that the organic solvent contained in the coating film can be volatilized. It is done. The baking conditions are the same as the pre-baking conditions for the resist coating film.
The presence or absence of baking can be appropriately determined in view of the material of the resist composition used for the resist film 2 as the lower layer. When prebaking is not performed in the step (1), it is preferable not to perform baking of the coating film made of the protective film forming composition.

[Step (3)]
In this embodiment, the resist film 2 formed in the step (1) and the protective film 3 formed in the step (2) are selectively exposed through a photomask 4. Thereby, in the exposure part 2a, a base generate | occur | produces from a photobase generator component by exposure.

The exposure amount may be such that an amount of base necessary for neutralizing the acid present in the exposed portion 2a can be generated from the photobase generator component.
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. ArF excimer laser, EUV, or EB is preferable because an easy to form a fine resist pattern, and ArF excimer laser is particularly preferable.
The photomask 4 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 on the unexposed area, and the alkali solution 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 4, but the present invention is not limited to this, and the selective exposure may be performed by exposure not through the photomask, for example, drawing such as EB. .

Exposure of the resist film 2 and the protective film 3 may be performed by normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or by exposure (immersion exposure) through an immersion medium. May be. By performing this step (3) by immersion exposure, a resist pattern with higher resolution can be formed.
In immersion exposure via an immersion medium, as described above, between the lens, which is conventionally filled with an inert gas such as air or nitrogen, and the support film 1 and the protective film 3 on the resist film 2 at the time of exposure. The exposure is performed in a state where the portion is filled with a solvent (immersion medium) having a refractive index larger than that of air.
More specifically, in the immersion exposure, a solvent (immersion medium) having a refractive index larger than the refractive index of air between the protective film 3 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 4.
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 preferable, and those having a boiling point of 80 to 160 ° C are more preferable. 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 this step (3), the resist film 2 and the protective film 3 are first exposed through the photomask 4 to form a first line and space pattern latent image, and then passed through the photomask 4. The second line and space pattern latent image may be formed (double exposure method) so that the second line and space pattern latent image intersects with the first line and space pattern latent image. .
The “latent image” means a region (exposed portion) of the resist film irradiated with radiation that has passed through the transmissive portion of the photomask.
When the above operation is performed, a lattice-like latent image in which the line-shaped latent image of the first line-and-space pattern intersects the line-shaped latent image of the second line-and-space pattern on the resist film 2 Is formed. When the operations of steps (4) and (5) described later are performed on the resist film 2, the area where the latent image is not formed (unexposed area) is dissolved and removed, while the exposed area is not removed. As a result, a fine and dense hole pattern is formed.

[Step (4)]
In this embodiment, baking (post-exposure baking (PEB)) is performed after the step (3).
The baking preferably has a temperature condition of about 50 to 200 ° C., more preferably about 80 to 150 ° C., still more preferably about 90 to 130 ° C .; baking time is preferably 10 to 300 seconds, more preferably 40 to 120 seconds, More preferably, it is preferably performed for 60 to 90 seconds.
As described above, when the resist film 2 and the protective film 3 are baked after exposure, the acidic compound component blended in the resist composition acts on the resist film 2 as a whole. The action increases the solubility of the base component in an alkaline developer. On the other hand, in the exposure part 2a, since the neutralization reaction of the base generated from the photobase generator component by the exposure and the acidic compound component proceeds, the acid that can act on the base material component is reduced. The solubility of the component in the alkaline developer does not change, or even if it changes, the amount of change is small. As a result, a difference (dissolution contrast) occurs in the dissolution rate of the exposed portion 2a and the unexposed portion 2b in the alkaline developer.
When the resist composition contains a thermal acid generator component as an acid supply component in addition to the acidic compound component, an acid is generated from the thermal acid generator component by PEB in this step. Since this acid is generated on the entire surface of the resist film, the exposed portion is neutralized by the base generated from the photobase generator component in the same manner as described above, and the unexposed portion has a solubility in the alkaline developer of the base component. Increase.
Moreover, when the composition for protective film formation contains an acidic compound component or a thermal acid generator, the acid generated from the acidic compound component contained in the protective film 3 or the thermal acid generator is protected by PEB in this step. It diffuses from the film 3 to the resist film 2, and an acid is supplied to the resist film 2. Since this acid is supplied to the entire surface of the resist film 2, the exposed portion is neutralized by the base generated from the photobase generator in the same manner as described above, and the unexposed portion is dissolved in the alkaline developer of the base material component. Further increase sex.
Due to the dissolution contrast, a high-resolution negative resist pattern is formed when alkali development is performed in the subsequent step (5).
In addition, the baking in this process (4) does not necessarily control the start of the said neutralization reaction.

[Step (5)]
In the present embodiment, after the step (4), by performing alkali development, the unexposed portion 2b of the resist film 2 is dissolved and removed, and the exposed portion 2a remains to form a negative resist pattern.
Specific examples of the alkali developer include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; Secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide and tetraethylammonium hydroxide Alkaline aqueous solutions such as cyclic amines such as pyrrole and pihelidine can be used.
Among them, the alkaline developer is preferably an alkaline aqueous solution containing at least one selected from the group consisting of primary amines, secondary amines, tertiary amines and quaternary ammonium salts. Among them, it is particularly preferable to use an aqueous solution of tetramethylammonium hydroxide (TMAH).
Furthermore, what added appropriate amount of alcohol and surfactant to the said alkaline aqueous solution can also be used.
The alkali concentration of the alkali developer (based on the concentration of inorganic alkali, quaternary ammonium salt or amine compound in the developer, and the total mass of the developer) is usually from 0.01 to 20% by mass.
The alkali development processing can be performed by a known method.
After the alkali development, a rinsing treatment with pure water or the like may be performed.
Further, after the alkali development, baking (post-baking) may be further performed. Post baking is usually performed under conditions of about 100 ° C. (because it is performed for the purpose of removing water after alkali development and rinsing), and the baking time is preferably 30 to 90 seconds.

  In addition, it is preferable that the protective film 3 formed on the resist film 2 is dissolved and removed by an alkali development process in step (5) by selecting a material (such as an alkali-soluble resin) for forming the protective film 3.

As mentioned above, although the embodiment was shown and the resist pattern formation method of this invention was shown, this invention is not limited to this.
For example, an acid generator (preferably a thermal acid generator) may be used together with the acidic compound component. Moreover, since the density | concentration of the acid when baking processing of the said PEB etc. performs increases, you may use an acid multiplication agent component together with an acidic compound component or an acidic compound component and an acid generator.

When a resist composition containing a thermal acid generator as an acid generator component is used, an acid is generated from the thermal acid generator in the entire resist film 2 by baking (PEB) in the step (4). And in the unexposed part 2b of the resist film 2, the solubility with respect to the alkali developing solution of a base material component increases by the effect | action of the acid generated from the thermal acid generator by this baking (PEB). On the other hand, in the exposed portion 2a of the resist film 2, the neutralization reaction between the acid generated from the thermal acid generator by this baking (PEB) and the base generated from the photobase generator component by the exposure in the above step (3). Progresses and the solubility of the base component in the alkaline developer does not change, or even if it changes, the amount of change becomes small. As a result, a difference (dissolution contrast) occurs in the dissolution rate of the exposed portion 2a and the unexposed portion 2b in the alkaline developer.
Therefore, when using a thermal acid generator in place of an acidic compound, by not performing pre-baking, the acid derived from the thermal acid generator does not act on the base material component between application and exposure until resist is applied. The contrast between the exposed portion 2a and the unexposed portion 2b of the film 2 can be improved, and a negative pattern with high resolution can be formed.

Moreover, a photo-acid generator can also be used instead of an acidic compound by selecting suitably the kind of a photomask, a base-material component, a photobase generator component, etc.
For example, a resist composition containing a photoacid generator having a relatively long diffusion length and a photobase generator having a relatively short diffusion length is used, and a photomask having a transparency (halftone type) is used as a photomask. Embodiment using a phase shift mask or the like. The diffusion length of the acid or base can be adjusted by the skeleton or polarity of the anion moiety in the photoacid generator for the acid, and the molecular weight or skeleton of the base after photolysis in the photobase generator for the base.
In this embodiment, the exposure in the step (3) generates a base from the photobase generator component and an acid from the photoacid generator in the exposed portion 2a. In the unexposed portion 2b, the protective group of the base material component is dissociated by the action of the acid generated in the exposed portion 2a and diffused to the unexposed portion 2b by the baking in the step (4) (deprotection reaction proceeds). ) To increase the solubility of the base component in an alkaline developer. On the other hand, in the exposed portion 2a, the neutralization reaction between the base and the acid generated in the step (3) proceeds, so that the solubility of the base material component in the alkaline developer does not change or the amount of change is slight even if it changes. It becomes. As a result, a difference (dissolution contrast) occurs in the dissolution rate of the exposed portion 2a and the unexposed portion 2b in the alkaline developer, and a negative pattern with high resolution can be formed.

In the resist pattern forming method of the present invention, after the negative resist pattern is formed as described above, the support 1 may be further etched using the negative resist pattern as a mask. A semiconductor device etc. can be manufactured by transcribe | transferring a resist pattern to the support body 1 by this etching.
A known method can be used for etching. For example, when the support 1 has an organic film on the substrate, the organic film is preferably etched by dry etching. In particular, from the viewpoint of production efficiency and the like, oxygen plasma etching or etching using CF ₄ gas or CHF ₃ gas is preferable, and oxygen plasma etching is more preferable.
Etching using a halogen gas is preferable for etching the substrate, etching using a fluorocarbon gas is more preferable, and etching using CF ₄ gas or CHF ₃ gas is particularly preferable.

According to the resist pattern forming method of the present invention, a high-resolution negative resist pattern can be formed by a development process in which a chemically amplified resist composition that has been made positive and an alkali developer are combined.
Therefore, according to the resist pattern forming method of the present invention, it is possible to form a resist pattern (an isolated trench pattern, a fine and dense contact hole pattern, etc.) that tends to generate a region with low optical intensity in the film thickness direction with high resolution.
Further, according to the resist pattern forming method of the present invention, it is possible to increase the density of the resist pattern. For example, a contact hole pattern in which individual holes are close to each other such that the distance between holes is about 30 to 50 nm. It can be formed in a good shape.
Moreover, the resist pattern formation method of this invention can be implemented using the existing exposure apparatus and the existing chemically amplified resist composition.

Furthermore, in the resist pattern forming method of the present invention, by providing the protective film 3 on the resist film 2, it is possible to prevent the acid of the resist film 2 from being deactivated by a basic substance in the environment. Therefore, in the step (4), the acid of the resist film 2 can increase the solubility of the base component in an alkaline developer in the unexposed portion, and the lithography characteristics and pattern shape of the resulting resist pattern are good. Become.
Moreover, since environmental impact can be reduced, even in the case of process delay (for example, when the time from the process (1) to the end of the process (3) or the time from the process (3) to the end of the process (4) is long). Good characteristics and shapes can be obtained, and the degree of freedom of the pattern formation process is increased.

≪Resist composition≫
In the resist pattern forming method of the present invention, at least a base component (hereinafter also referred to as “component (A)”) whose solubility in an alkaline developer is increased by the action of an acid, and a photobase that generates a base upon exposure. A resist composition containing a generator component (hereinafter also referred to as “(C) component”) and an acidic compound component (hereinafter also referred to as “(G) component”) is used.
Hereinafter, each component will be described.

<Base component; component (A)>
The component (A) is a base material component whose solubility in an alkaline developer is increased by the action of an acid.
The “base component” is an organic compound having a film forming ability, and an organic compound having a molecular weight of 500 or more is preferably 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.
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.

As the component (A), a base material component (hereinafter also referred to as “component (A0)”) whose polarity is increased by the action of an acid is preferably used.
In the present invention, when the component (A0) is used, since the polarity of the unexposed portion of the component (A0) changes before and after baking in the step (4), good development contrast can be obtained by alkali development.
The component (A0) may be a resin component whose polarity is increased by the action of an acid, a low molecular compound component whose polarity is increased by the action of an acid, or a mixture thereof. .
The component (A0) is preferably a resin component whose polarity increases by the action of an acid, and in particular, a polymer compound having a structural unit (a1) containing an acid-decomposable group whose polarity increases by the action of an acid ( Those containing A1) (hereinafter referred to as “component (A1)”) are preferred.
In addition to the structural unit (a1), the component (A1) further includes a structural unit (a0) containing a —SO ₂ — containing cyclic group and a structural unit (a2) containing a lactone-containing cyclic group. Those having at least one selected structural unit are preferred.
The component (A1) includes, in addition to the structural unit (a1), or at least one structural unit selected from the group consisting of the structural unit (a0) and the structural unit (a2) and the structural unit (a1). In addition, the compound having a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group is preferable.

[Structural unit (a1)]
The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.
The “acid-decomposable group” is an acid-decomposable group that can cleave at least part of 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 must 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) increases. As the polarity increases, the solubility in the developer changes relatively, and when the developer is an alkaline developer, the solubility increases.

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 a ring skeleton of a monovalent aliphatic cyclic group, a substituent (on a carbon atom bonded to an atom adjacent to the acid dissociable group (for example, —O— in —C (═O) —O—)) 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.
The cyclic alkyl group preferably has 3 to 20 carbon atoms, and more preferably 4 to 12 carbon atoms. 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. Some of the carbon atoms constituting the ring of the cyclic alkyl group may be substituted with an etheric oxygen atom (—O—).
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 the same alkyl groups as mentioned as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylate ester described later. A methyl group or an ethyl group is preferred, and a methyl group is most preferred.
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. ]

Examples of the alkyl group for Y include the same alkyl groups as those described above for the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylate ester.
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 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 an acid whose polarity is increased by the action of an acid. A structural unit containing a decomposable group; a structural unit in which at least a part of hydrogen atoms in the hydroxyl group of a structural unit derived from hydroxystyrene or a hydroxystyrene derivative is protected by a substituent containing the acid-decomposable group; vinylbenzoic acid or Examples include a structural unit in which at least a part of hydrogen atoms in —C (═O) —OH of a structural unit derived from a vinylbenzoic acid derivative is protected by a substituent containing the acid-decomposable group.
Preferred examples of the substituent containing an acid-decomposable group include the tertiary alkyl ester type acid dissociable group and the acetal type acid dissociable group described above.

Here, in the present specification and claims, 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, an acrylate 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 an α-substituted acrylate ester. Further, the acrylate ester and the α-substituted acrylate ester may be collectively referred to as “(α-substituted) acrylate 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.
Specific examples of the hydroxyalkyl group as a substituent at the α-position include a group in which part or all of the hydrogen atoms of the “alkyl group as the substituent at the α-position” are substituted with a hydroxyl group. 1-5 are preferable and, as for the number of the hydroxyl groups in this hydroxyalkyl group, 1 is the most 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.

“A structural unit derived from hydroxystyrene or a hydroxystyrene derivative” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene or a hydroxystyrene derivative.
“Hydroxystyrene derivative” is a concept including those in which the hydrogen atom at the α-position of hydroxystyrene is substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. The derivatives include those in which the hydrogen atom at the α-position may be substituted with a substituent, the hydrogen atom of the hydroxyl group of hydroxystyrene substituted with an organic group, and the hydrogen atom at the α-position substituted with a substituent. Examples include those in which a substituent other than a hydroxyl group is bonded to a good benzene ring of hydroxystyrene. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent for substituting the hydrogen atom at the α-position of hydroxystyrene include the same substituents as those mentioned as the substituent at the α-position in the α-substituted acrylic ester. Among these, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorination having 1 to 5 carbon atoms. An alkyl group is more preferable, and a hydrogen atom or a methyl group is most preferable from the viewpoint of industrial availability.
Examples of the substituent other than the hydroxyl group that may be bonded to the benzene ring of hydroxystyrene, in which the hydrogen atom at the α-position may be substituted, include a halogen atom, an alkyl group having 1 to 5 carbon atoms, carbon Examples thereof include halogenated alkyl groups of 1 to 5, -COOX ^e (X ^e is a hydrogen atom or an organic group), and the like. 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.

The “structural unit derived from vinyl benzoic acid or a vinyl benzoic acid derivative” means a structural unit configured by cleavage of an ethylenic double bond of vinyl benzoic acid or a vinyl benzoic acid derivative.
The “vinyl benzoic acid derivative” is a concept including a compound in which the hydrogen atom at the α-position of vinyl benzoic acid is substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. These derivatives include those obtained by substituting the hydrogen atom of the carboxy group of vinyl benzoic acid with an organic group, which may be substituted with a hydrogen atom at the α-position, and the hydrogen atom at the α-position with a substituent. Examples thereof include those in which a substituent other than a hydroxyl group and a carboxy group is bonded to the benzene ring of vinyl benzoic acid. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent for substituting the hydrogen atom at the α-position of vinyl benzoate include the same as those mentioned as the substituent at the α-position in the α-substituted acrylic ester. Among these, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorination having 1 to 5 carbon atoms. An alkyl group is more preferable, and a hydrogen atom or a methyl group is most preferable from the viewpoint of industrial availability.
Examples of the substituent other than the hydroxyl group and the carboxy group that may be bonded to the benzene ring of vinyl benzoic acid, in which the hydrogen atom at the α-position may be substituted, include, for example, a halogen atom, a carbon number of 1 to 5 An alkyl group, a C1-C5 halogenated alkyl group, etc. are mentioned. 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.

As the structural unit (a1), among the above, a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent is preferable.
More specifically, examples of the structural unit (a1) include structural units represented by general formula (a1-0-1) shown below, structural units represented by general formula (a1-0-2) shown below, 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 general formula (a1-0-1), the alkyl group and the halogenated alkyl group of R are each exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylate ester. And the same alkyl groups and halogenated alkyl groups. 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 is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as the divalent hydrocarbon group in Y ² preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, and 6 to 6 carbon atoms. 15 is particularly preferable, and 6 to 10 is most preferable. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic ring possessed by 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.) Group in which one hydrogen atom is further removed from the aryl group in the group); and the like. 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 the above, as the divalent linking group for Y ² , in particular, a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom is included. preferable. Among these, a linear or branched alkylene group or a divalent linking group containing a hetero atom is preferable.

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

［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.
The Y ^2, the same groups as those described above for ^{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 (a1), a structural unit represented by the following general formula (a1-0-11), a structural unit represented by the following general formula (a1-0-12), and the following general formula ( a1-0-13), a structural unit represented by the following general formula (a1-0-14), a structural unit represented by the following general formula (a1-0-15), and the following general unit It is preferable to have at least one selected from the group consisting of structural units represented by formula (a1-0-2).
Especially, the structural unit represented by the following general formula (a1-0-11), the structural unit represented by the following general formula (a1-0-12), and the following general formula (a1-0-13) And at least one selected from the group consisting of structural units represented by the following general formula (a1-0-14) and structural units represented by the following general formula (a1-0-15) It is more preferable.

［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; 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). 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), (a1-1-32), and (a1-1-33) is preferable. Moreover, the structural unit represented by the following (a1-1-02 ′) is also preferable.
In each formula, h is an integer of 1 to 4, and 1 or 2 is preferable.

［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 the formula (a1-0-13) include formulas (a1-1-1) to (a1-1-2) exemplified as specific examples of the 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) or (a1-1-2) 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 the aforementioned —Y ²¹ —O—Y ²² — or —Y ²¹ —C (═O) —O—Y ^22. Those 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、ｅ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, e 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).
e 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、ｔ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 t is an integer of 0 to 3, respectively. ]

In formulas (a1-3-03-1) to (a1-3-03-2), a ′ is the same as described above, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, or 1 or 2 is particularly preferred.
b ′ is the same as described above, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and particularly preferably 1 or 2.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.
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.

As the structural unit (a1) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
In the component (A1), the proportion of the structural unit (a1) is preferably from 15 to 70 mol%, more preferably from 15 to 60 mol%, more preferably from 20 to 55 mol%, based on all the structural units constituting the component (A1). Is more preferable.
By setting the proportion 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 LWR are also improved. Moreover, it becomes easy to balance with another structural unit by setting it as an upper limit or less.

[Structural unit (a0)]
The structural unit (a0) is a structural unit containing a —SO ₂ — containing cyclic group.
The structural unit (a0) contains a —SO ₂ — containing cyclic group, thereby improving the adhesion of the resist film formed using the resist composition containing the component (A1) to the substrate. Further, it contributes to the improvement of lithography characteristics such as sensitivity, resolution, exposure margin (EL margin), LWR (line width roughness), LER (line edge roughness), mask reproducibility and the like.
Here _- as "-SO 2 containing cyclic group", -SO 2 _- within the ring skeleton thereof shows a cyclic group containing a ring containing, in particular, -SO 2 _- in the sulfur atom (S ) Is a cyclic group that forms part of the ring skeleton of the cyclic group.
-SO 2 _- In-containing cyclic group, within the ring skeleton thereof -SO 2 _- in a ring containing as the first ring, when in the case of the ring only having a single cyclic group, yet another ring structure Is referred to as a polycyclic group regardless of its structure.
The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
The —SO ₂ — containing cyclic group is particularly a cyclic group containing —O—SO ₂ — in the ring skeleton, that is, a ring skeleton in which —O—S— in —O—SO ₂ — is a cyclic group. It is preferable that it is a sultone ring which forms a part of.
The —SO ₂ — containing cyclic group preferably has 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. . 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 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 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 group, a group in which two hydrogen atoms have been 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 ″ (R ″ represents a hydrogen atom or an alkyl group). Group), a hydroxyalkyl group, a cyano group, and the like.
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 preferably 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 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 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 and the like.
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^６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 ⁶ 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 ⁶ may be the same or different.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ⁶ , 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.

As the structural unit (a0), any unit can be used without any particular limitation as long as it includes a —SO ₂ — containing cyclic group.
The structural unit (a0) 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 a —SO ₂ — containing cyclic group. A structural unit is preferred.
More specifically, examples of the structural unit (a0) include structural units represented by general formula (a0-0) 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^３９は−Ｏ−又は−ＮＨ−であり、Ｒ^３０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 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 ³⁹ is —O— or —NH—, and R ³⁰ is —SO ₂ -Containing cyclic group, R ²⁹ 'is a single bond or a divalent linking group. ]

In formula (a0-0), 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.
The alkyl group having 1 to 5 carbon atoms in R 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- Examples thereof include a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group.
The halogenated alkyl group in R 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 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 is most preferably a hydrogen atom or a methyl group in terms of industrial availability.
In the formula (a0-0), R ³⁹ represents —O— or —NH—.
In the formula (a0-0), R ³⁰ is the same as the —SO ₂ -containing cyclic group mentioned above.

In the formula (a0-0), 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 ′ include those listed as the divalent linking group for Y ² in the general formula (a1-0-2) mentioned in the description of the structural unit (a1). The same thing is mentioned.
The divalent linking group for R ²⁹ ′ is preferably an alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom. Among these, those containing an alkylene group and 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 mentioned as the aliphatic hydrocarbon group for Y ² can be used.
As the divalent linking group containing an ester bond, in particular, the general formula: —R ²⁰ —C (═O) —O— [wherein R ²⁰ is a divalent linking group. ] Is preferable. That is, the structural unit (a0) is preferably a structural unit represented by the following general formula (a0-0-1).

［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り、Ｒ^３９は−Ｏ−又は−ＮＨ−であり、Ｒ^２０は２価の連結基であり、Ｒ^３０は−ＳＯ_２−含有環式基である。］

[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 ³⁹ represents —O— or —NH—, and R ²⁰ represents a divalent group. A linking group, R ³⁰ is a —SO ₂ — containing cyclic group; ]

R ²⁰ is not particularly limited, and examples thereof include those similar to those exemplified as the divalent linking group for R ²⁹ ′ in the general formula (a0-0).
The divalent linking group for R ²⁰ is preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom.
Examples of the linear or branched alkylene group, divalent alicyclic hydrocarbon group, and divalent linking group containing a hetero atom include the linear groups mentioned above as preferred for R ²⁹ ′. Or the same thing as the branched alkylene group, the bivalent alicyclic hydrocarbon group, and the bivalent coupling group containing a hetero atom is mentioned.
Among these, a linear or 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.
As the divalent linking group containing an oxygen atom, a divalent linking group containing an ether bond or an ester bond is preferable, and the above-described formula —Y ²¹ —O—Y ²² —, formula — [Y ²¹ —C (═O ^{_{) -O] m '- Y 22}} - or the formula ^{-Y 21 -O-C (= O} ) -Y 22 - group represented by is more preferable. Y ²¹ , Y ²² and m ′ are the same as described above.
Among them, a group represented by the formula —Y ²¹ —O—C (═O) —Y ²² — is preferable, and a group represented by the formula — (CH ₂ ) _c —O—C (═O) — (CH ₂ ) _d — The groups represented are particularly preferred. c is an integer of 1 to 5, an integer of 1 to 3 is preferable, and 1 or 2 is more preferable. d is an integer of 1 to 5, an integer of 1 to 3 is preferable, and 1 or 2 is more preferable.

  As the structural unit (a0), a structural unit represented by general formula (a0-0-11) or (a0-0-12) shown below is preferable, and a structural unit represented by formula (a0-0-12) is preferable. Units are more preferred.

［式中、Ｒ、Ａ’、Ｒ^６、ｚ、Ｒ^３９およびＲ^２０はそれぞれ前記と同じである。］

[Wherein, R, A ′, R ⁶ , z, R ³⁹ and R ²⁰ are the same as defined above. ]

In formula (a0-0-11), A ′ is preferably a methylene group, an ethylene group, an oxygen atom (—O—) or a sulfur atom (—S—).
In formula (a0-0-12), R ²⁰ 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 ^20, the linear or branched alkylene group and the divalent linking group containing an oxygen atom respectively mentioned above are used. Examples are the same as the linking group.
As the structural unit represented by the formula (a0-0-12), a structural unit represented by the following general formula (a0-0-12a) or (a0-0-12b) is particularly preferable.

［式中、Ｒ、Ｒ^３９およびＡ’はそれぞれ前記と同じであり、ｃ及びｄはそれぞれ前記と同じであり、ｆは１〜５の整数（好ましくは１〜３の整数）である。］

[Wherein, R, R ³⁹ and A ′ are the same as defined above, c and d are the same as defined above, and f is an integer of 1 to 5 (preferably an integer of 1 to 3). ]

As the structural unit (a0) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
The proportion of the structural unit (a0) in the component (A1) is such that the resist pattern shape formed using the resist composition containing the component (A1) becomes good, and lithography such as EL margin, LWR, mask reproducibility, etc. From the viewpoint of excellent properties, it is preferably 1 to 60 mol%, more preferably 5 to 55 mol%, still more preferably 10 to 50 mol%, based on the total of all structural units constituting the component (A1). 15 to 45 mol% is most preferable.

[Structural unit (a2)]
The structural unit (a2) is a structural unit containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing a —O—C (═O) — structure. 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.
When the lactone cyclic group of the structural unit (a2) is used for forming a resist film, the component (A1) is used to improve the adhesion of the resist film to the substrate or to contain a developer containing water (particularly an alkali development process). In the case of ()).

The lactone cyclic group is not particularly limited, and any lactone 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 contains a lactone-containing cyclic group, and any structural unit can be used.
The structural unit (a2) 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 a lactone-containing cyclic group. preferable.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) 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’はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、酸素原子（＝Ｏ）、−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または１〜２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の整数である。］

[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, a halogen atom, or a halogen atom. alkyl group, a hydroxyl group, an oxygen atom (= O), - COOR " , - OC (= O) R", a hydroxyalkyl group or a cyano group, R "represents a hydrogen atom or an alkyl ^{group; R 29} is a single A bond or a divalent linking group, s ″ is 0 or an integer of 1 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 sulfur. An atom; m is an integer of 0 or 1.]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group of R ′ each have a —SO ₂ — containing cyclic group. Alkyl groups, alkoxy groups, halogen atoms, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, hydroxyalkyl groups, —COOR ″, —OC (═O) R, which may be enumerated as substituents. Examples thereof include “(R” is the same as above).
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.
R ²⁹ is a single bond or a divalent linking group. The divalent linking group is the same as the divalent linking group described for Y ² in the general formula (a1-0-2), and among them, an alkylene group and an ester bond (—C (═O ) -O-) or a combination thereof. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same linear alkylene groups and branched alkylene groups as those described above for the aliphatic hydrocarbon group for Y ² can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are illustrated below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a2) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
As the structural unit (a2), 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 formulas (a2-1) to ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-7), (a2-3-1) and (a2-3-5) It is preferable to use at least one selected from the group consisting of structural units represented by

The proportion of the structural unit (a2) in the component (A1) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, based on the total of all the structural units constituting the component (A1). More preferably, it is 45 mol%.
By setting the proportion of the structural unit (a2) to the lower limit value or more, the effect of including the structural unit (a2) is sufficiently obtained, and by setting the proportion of the structural unit (a2) to the upper limit value or less, balance with other structural units is achieved. It becomes easy.

[Structural unit (a3)]
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (excluding those corresponding to the structural units (a1), (a0), and (a2) described above).
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) increases, which contributes to the improvement of resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group. For example, a resin for a resist composition for an ArF excimer laser can be appropriately selected from those proposed. The cyclic group is preferably a polycyclic group, and more preferably 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

The structural unit (a3) is not particularly limited as long as it contains a polar group-containing aliphatic hydrocarbon group, and any structural unit can be used.
The structural unit (a3) 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 a polar group-containing aliphatic hydrocarbon group A structural unit is preferred.
The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the formula (a3-2), the formula ( The structural unit represented by a3-3) is preferred.

[式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。]

[Wherein, R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t ′ is an integer of 1 to 3, and l is an integer of 1 to 5] And s is an integer of 1 to 3. ]

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and it is particularly preferred that the hydroxyl group is bonded to the 3-position of the adamantyl group.

  In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on the total of all structural units constituting the component (A1). 5 to 25 mol% is more preferable.
By setting the proportion of the structural unit (a3) to the lower limit value or more, the effect of including the structural unit (a3) can be sufficiently obtained, and by setting the proportion of the structural unit (a3) to the upper limit value or less, balance with other structural units can be obtained. It becomes easy.

[Other structural units]
The component (A1) has other structural units other than the structural unit (a1), the structural unit (a0), the structural unit (a2), and the structural unit (a3) as long as the effects of the present invention are not impaired. May be.
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 can be used.
Such other structural unit 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 is a non-acid dissociable aliphatic polycyclic A structural unit containing a group (a4), a structural unit derived from hydroxystyrene in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and hydrogen bonded to the α-position carbon atom Examples thereof include a structural unit (a6) derived from styrene in which an atom may be substituted with a substituent.

(Structural unit (a4))
The structural unit (a4) 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 is a non-acid-dissociable aliphatic polycyclic group Is a structural unit including
In the structural unit (a4), examples of the polycyclic group include the same polycyclic groups as exemplified in the case of the structural unit (a1). For ArF excimer laser, KrF excimer Many things conventionally known as what is used for the resin component of resist compositions, such as for lasers (preferably for ArF excimer lasers), can be used.
In particular, 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. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

[式中、Ｒは前記と同じである。]

[Wherein, R is the same as defined above. ]

  When the structural unit (a4) is contained in the component (A1), the structural unit (a4) is preferably contained in an amount of 1 to 30 mol% based on the total of all the structural units constituting the component (A1). 10 to 20 mol% is more preferable.

(Structural unit (a5))
The structural unit (a5) is a structural unit derived from hydroxystyrene in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent.
The “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
The substituent that may substitute the hydrogen atom at the α-position of hydroxystyrene is the α-position of hydroxystyrene in the “structural unit derived from hydroxystyrene or a hydroxystyrene derivative” in the description of the structural unit (a1). The same thing as the thing quoted as a substituent which substitutes hydrogen atom of these is mentioned. Specific examples include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, and a hydroxyalkyl group. Among them, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferable. .
A substituent other than a hydroxyl group may be bonded to the benzene ring of hydroxystyrene. 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. Among these, an alkyl group having 1 to 5 carbon atoms is preferable among them.

  As the structural unit (a5), the following general formula (a5-1) can be used because it has good solubility in organic solvents, has solubility in an alkaline developer, and has excellent etching resistance. The structural unit represented by can be illustrated suitably.

［式中、Ｒ^６０は水素原子又は炭素数１〜５のアルキル基であり；Ｒ^６１は炭素数１〜５のアルキル基であり；ｐは１〜３の整数であり；ｑは０〜２の整数である。］

[Wherein, R ⁶⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; R ⁶¹ is an alkyl group having 1 to 5 carbon atoms; p is an integer of 1 to 3; q is 0 to 2] Is an integer. ]

In the formula (a5-1), as the alkyl group having 1 to 5 carbon atoms in R ⁶⁰ , specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl And linear or branched alkyl groups such as a group, a pentyl group, an isopentyl group, and a neopentyl group. R ⁶⁰ is particularly preferably a hydrogen atom or a methyl group.
p is an integer of 1 to 3, preferably 1.
The bonding position of the hydroxyl group may be any of the o-position, m-position and p-position of the phenyl group. When p is 1, the p-position is preferred because it is readily available and inexpensive. When p is 2 or 3, arbitrary substitution positions can be combined.
q is an integer of 0-2. Among these, q is preferably 0 or 1, and is preferably 0 industrially.
As the alkyl group for R ^61, the same alkyl groups for R ⁶⁰ can be mentioned.
When q is 1, the substitution position of R ⁶¹ may be any of the o-position, the m-position, and the p-position. When q is 2, arbitrary substitution positions can be combined. At this time, the plurality of R ⁶¹ may be the same or different.

  When the structural unit (a5) is contained in the component (A1), the structural unit (a5) is preferably contained in an amount of 50 to 90 mol% based on the total of all the structural units constituting the component (A1). It is more preferable to make it contain 55-85 mol%, and it is still more preferable to contain 60-80 mol%.

(Structural unit (a6))
The structural unit (a6) is a structural unit derived from styrene in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent.
The “structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.
Examples of the substituent that may substitute the α-position hydrogen atom of styrene are the same as those mentioned as the substituent that may substitute the α-position hydrogen atom of hydroxystyrene in the description of the structural unit (a5). Can be mentioned. Among them, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms is preferable.
A substituent may be bonded to the benzene ring of styrene. Examples of the substituent include the same groups as those described above for the substituent that may be bonded to the benzene ring of hydroxystyrene in the description of the structural unit (a5). Among these, a C1-C5 alkyl group is preferable.

  As the structural unit (a6), the solubility in an alkali developer can be adjusted, and since the heat resistance and dry etching resistance are improved, the structural unit represented by the following general formula (a6-1) is It can illustrate suitably.

［式中、Ｒ^６０は水素原子又は炭素数１〜５のアルキル基であり；Ｒ^６２は炭素数１〜５のアルキル基であり；ｘは０〜３の整数である。］

[Wherein, R ⁶⁰ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; R ⁶² is an alkyl group having 1 to 5 carbon atoms; x is an integer of 0 to 3; ]

In the general formula ^{(a6-1), R 60} is the same as ^{R 60} in the general formula (a5-1).
In the formula ^(a6-1), the alkyl group of ^{R 62} is the same as the alkyl group of ^{R 61} in general formula (a5-1).
x is an integer of 0 to 3, preferably 0 or 1, and industrially particularly preferably 0.
When x is ^1, the substitution position of ^{R 62} is a phenyl group the o-, m- position may be any of p- position. When x is 2 or 3, any substitution position can be combined. At this time, the plurality of R ⁶² may be the same or different.

  When the structural unit (a6) is contained in the component (A1), the structural unit (a6) is preferably contained in an amount of 10 to 50 mol% based on the total of all the structural units constituting the component (A1). It is more preferable to make it contain 15-45 mol%, and it is still more preferable to contain 20-40 mol%.

The component (A1) is preferably a polymer having the structural unit (a1).
Specifically, as the component (A1), a copolymer having a repeating structure of the structural unit (a1) and the structural unit (a2); a copolymer having a repeating structure of the structural unit (a1) and the structural unit (a0); A copolymer comprising a repeating structure of the structural unit (a1), the structural unit (a2) and the structural unit (a3); a copolymer comprising a repeating structure of the structural unit (a1), the structural unit (a0) and the structural unit (a3) Copolymers: Examples of the copolymer include a repeating structure of the structural unit (a1), the structural unit (a0), the structural unit (a2), and the structural unit (a3).

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, 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) 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
A commercially available monomer may be used as the monomer for deriving each structural unit, or the monomer may be synthesized using a known method.

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 preferably 25% by mass or more, more preferably 50% by mass, further preferably 75% by mass, and 100% by mass with respect to the total mass of the component (A). May be. When the ratio is 25% by mass or more, lithography properties such as MEF, circularity, and roughness reduction are further improved.

The component (A) may contain a base material component (hereinafter referred to as “component (A2)”) whose polarity is increased by the action of an acid other than the component (A1) as long as the effects of the present invention are not impaired. Good.
Examples of the component (A2) include low molecular compounds having a molecular weight of 500 or more and less than 4000 and having an acid dissociable group and a hydrophilic group as exemplified in the description of the component (A1). Specific examples include those in which some or all of the hydrogen atoms of the hydroxyl group of the compound having a plurality of phenol skeletons are substituted with the acid dissociable group.
Examples of the low molecular weight compound include sensitizers in non-chemically amplified g-line and i-line resists, and some of the hydrogen atoms of the hydroxyl groups of low molecular weight phenolic compounds known as heat resistance improvers. Those substituted with a dissociable group are preferred, and any of them can be used arbitrarily.
Examples of the low molecular weight phenol compound include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxypheny Rumethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2 to 6 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol and xylenol. Of course, it is not limited to these. In particular, a phenol compound having 2 to 6 triphenylmethane skeletons is preferable because of excellent resolution and line edge roughness (LWR). The acid dissociable group is not particularly limited, and examples thereof include those described above.

  In the resist composition used in the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<Photobase generator component; (C) component>
In the resist pattern forming method of the present invention, the component (C) is decomposed by the exposure energy in the step (3) to generate a base, whereby a good dissolution contrast can be obtained.
The component (C) is not limited as long as it can be decomposed by irradiation with radiation to generate a base, and includes a carbamate group (urethane bond), an acyloxyimino group, and an ionic compound (anion-cation complex). ), Carbamoyloxyimino group-containing ones, and the like. Carbamate group (urethane bond) -containing ones, acyloxyimino group-containing ones, and ionic ones (anion-cation complex) are preferred.
Moreover, what has a ring structure in a molecule | numerator is preferable, and what has ring skeletons, such as benzene, naphthalene, anthracene, xanthone, thioxanthone, anthraquinone, fluorene, is mentioned as the said ring structure.

Especially, as (C) component, the compound (henceforth "(C1) component") represented with the following general formula (C1) from a photodegradable point is especially preferable. When such a compound is irradiated with radiation, at least the bond between the nitrogen atom in the formula (C1) and the carbon atom of the carbonyl group adjacent to the nitrogen atom is cleaved, resulting in amine or ammonia and carbon dioxide. And generate. After decomposition, it is preferred that the product having -N (R ¹ ) (R ² ) has a high boiling point. Moreover, it is preferable from the point of the diffusion control at the time of PEB that the molecular weight of the product which has -N (R < ¹ >) (R < ² >) is large or has a bulky skeleton.

［式中、Ｒ^１およびＲ^２はそれぞれ独立に水素原子またはヘテロ原子を含んでいてもよい１価の炭化水素基であり、Ｒ^１およびＲ^２が相互に結合して隣接する窒素原子とともに環式基を形成してもよく；Ｒ^３は１価の光官能基である。］

[Wherein, R ¹ and R ² are each independently a monovalent hydrocarbon group which may contain a hydrogen atom or a hetero atom, and R ¹ and R ² are bonded to each other to form a ring together with an adjacent nitrogen atom. Formula groups may be formed; R ³ is a monovalent photofunctional group. ]

In Formula (C1), the hetero atom that the hydrocarbon group in R ¹ and R ² may have is an atom other than a carbon atom and a hydrogen atom, such as an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc. Is mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group, and is preferably an aliphatic hydrocarbon group.

In formula (C1), the aromatic hydrocarbon group in R ¹ and R ² is a hydrocarbon group having an aromatic ring.
The number of carbon atoms of the aromatic hydrocarbon group in R ¹ and R ² is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and 6 to 12 is most preferred. 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 benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and the like. 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.
In addition, when the aromatic hydrocarbon group has an aliphatic hydrocarbon group bonded to an aromatic ring, a part of carbon atoms constituting the aliphatic hydrocarbon group is substituted with a divalent linking group containing a hetero atom. Or a part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent. The aliphatic hydrocarbon group and the divalent linking group containing a hetero atom each include an aliphatic hydrocarbon group and a hetero atom which will be mentioned later in the description of the aliphatic hydrocarbon group for R ¹ and R ² . The thing similar to a bivalent coupling group is mentioned.

Examples of the aromatic hydrocarbon group in which a part of carbon atoms constituting the aromatic ring is substituted with a hetero atom include a part of carbon atoms constituting the ring of the aryl group as an oxygen atom, a sulfur atom, and a nitrogen atom. A heteroaryl group substituted with a heteroatom such as the above, a heteroarylalkyl group in which a part of carbon atoms constituting the aromatic hydrocarbon ring in the arylalkyl group is substituted with the heteroatom, and the like.
Examples of the substituent that replaces the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyalkyl group, a hydroxyl group, and an oxygen atom (= O). , -COOR ", - OC (= O) R", a cyano group, a nitro ^{_{group, -NR "2, -R 9 '}} -N (R 10') -C (= O) -O-R 5 ', containing And nitrogen heterocyclic groups.
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 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.
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.

R ″ in —COOR ″, —OC (═O) R ″, and —NR ″ ₂ 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 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 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 and the like.
Two R ″ in —NR ″ ₂ may be the same or different.
—R ⁹ ′ —N (R ¹⁰ ′) —C (═O) —O—R ⁵ ′, R ⁹ ′ is a divalent hydrocarbon group that may contain a hetero atom, and R ¹⁰ ′ is It is a monovalent hydrocarbon group which may contain a hydrogen atom or a hetero atom, and R ⁵ ′ is a monovalent organic group having an aliphatic ring or an aromatic ring.
Examples of the hydrocarbon group for R ⁹ ′ include groups in which one hydrogen atom has been removed from the hydrocarbon group for R ¹ in formula (C1).
R ¹⁰ ′ and R ⁵ ′ may be the same as R ² and R ^{3 in} formula (C1), respectively.
In —R ⁹ ′ —N (R ¹⁰ ′) —C (═O) —O—R ⁵ ′, R ¹⁰ ′ may be bonded to R ⁹ ′ to form a ring.
Of R ¹ and R ^{2 in} formula (C1), for example, when R ¹ has —R ⁹ ′ —N (R ¹⁰ ′) —C (═O) —O—R ⁵ ′ as a substituent, the formula R ¹⁰ ′ therein may be bonded to R ² in Formula (C1) to form a ring.
Of R ¹ and R ² in the formula (C1), when R ¹ has —R ⁹ ′ —N (R ¹⁰ ′) —C (═O) —O—R ⁵ ′ as a substituent, the formula (C1 ) Is represented by the following general formula: R ⁵ ′ —O—C (═O) —N (R ¹⁰ ′) —R ⁴ —N (R ² ) —C (═O) —O— R ³ [wherein R ^{2 to} R ³ , R ¹⁰ ′ and R ⁵ ′ are the same as defined above, and R ⁴ represents a divalent aliphatic hydrocarbon group. ] The compound represented by this is preferable.
Examples of the divalent aliphatic hydrocarbon group for R ⁴ include groups obtained by removing one hydrogen atom from the aliphatic hydrocarbon groups for R ¹ and R ² described later.

The “nitrogen-containing heterocyclic group” as the substituent is a group obtained by removing one or more hydrogen atoms from a nitrogen-containing heterocyclic compound containing a nitrogen atom in the ring skeleton. The nitrogen-containing heterocyclic compound may have a hetero atom (for example, an oxygen atom, a sulfur atom, etc.) other than a carbon atom and a nitrogen atom in its ring skeleton.
The nitrogen-containing heterocyclic compound may be aromatic or aliphatic. Moreover, when aliphatic, it may be saturated or unsaturated. The nitrogen-containing heterocyclic compound may be monocyclic or polycyclic.
The nitrogen-containing heterocyclic compound preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, and still more preferably 5 to 20 carbon atoms.
Specific examples of the monocyclic nitrogen-containing heterocyclic compound include pyrrole, pyridine, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, pyrimidine, pyrazine, 1,3,5- Examples include triazine, tetrazole, piperidine, piperazine, pyrrolidine, morpholine and the like.
Specific examples of the polycyclic nitrogen-containing heterocyclic compound include quinoline, isoquinoline, indole, pyrrolo [2,3-b] pyridine, indazole, benzimidazole (benzimidazole), benzotriazole, carbazole, acridine, 1, 5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, etc. Is mentioned.
The nitrogen-containing heterocyclic group may have a substituent. Examples of the substituent include those similar to those exemplified as the substituent for substituting the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group.

In formula (C1), the aliphatic hydrocarbon group in R ¹ and R ² means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for R ¹ and R ² may be saturated (alkyl group) or unsaturated. Usually, it is preferably saturated. The aliphatic hydrocarbon group may be linear, branched, or cyclic, or a combination thereof. Examples of the combination include a group in which a cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and a cyclic aliphatic hydrocarbon group in a linear or branched chain. And a group intervening in the middle of the aliphatic hydrocarbon group.
The linear or branched alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and still more preferably 1 to 10 carbon atoms.
Specific examples of the linear alkyl group include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, Examples include tridecyl group, isotridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
Specific examples of the branched alkyl group include 1-methylethyl group (iso-propyl group), 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3- Examples include methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, tert-butyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.
The cyclic alkyl 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. Specific examples include a group in which one hydrogen atom has been removed from a monocycloalkane; a group in which one hydrogen atom has been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. . More specifically, examples of the group obtained by removing one hydrogen atom from a monocycloalkane include a cyclopentyl group and a cyclohexyl group. Examples of the group obtained by removing one hydrogen atom from polycycloalkane include an adamantyl group, norbornyl group, isobornyl group, tricyclodecyl group, tetracyclododecyl group, and the like.

The aliphatic hydrocarbon group may have a substituent. For example, part of the carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a divalent linking group containing a hetero atom, and part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group May be substituted with a substituent.
In the divalent linking group containing a heteroatom, examples of the heteroatom include the same heteroatoms as those substituted for a part of the carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group. . Examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —, —C (═O) —O—, and carbonate bond (—O—C (═O) —O—. _{), - S -, - S} (= O) 2 -, - S (= O) 2 -O -, - NH -, - NR 04 - (R 04 is an alkyl group, a substituent such as an acyl group. ), -NH-C (= O)-, = N- and the like, and divalent non-hydrocarbon groups containing a hetero atom. Moreover, the combination etc. of these "divalent non-hydrocarbon groups containing a hetero atom" and a divalent aliphatic hydrocarbon group are mentioned. Examples of the divalent aliphatic hydrocarbon group include groups obtained by removing one hydrogen atom from the above-described aliphatic hydrocarbon group, and a linear or branched aliphatic hydrocarbon group is preferable.
Examples of the substituent of the aliphatic hydrocarbon group in the latter example include the same substituents as those mentioned as the substituents for substituting the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group.

In the general formula (C1), R ¹ and R ² may be bonded to each other to form a cyclic group together with the adjacent nitrogen atom.
The cyclic group may be an aromatic cyclic group or an aliphatic cyclic group. When it is an aliphatic cyclic group, it may be saturated or unsaturated. Usually, it is preferably saturated.
The cyclic group may have a nitrogen atom other than the nitrogen atom to which R ¹ and R ² are bonded in the ring skeleton. Further, the ring skeleton may have a hetero atom other than a carbon atom and a nitrogen atom (for example, an oxygen atom, a sulfur atom, etc.).
The cyclic group may be monocyclic or polycyclic.
In the case of monocyclic, the number of atoms constituting the skeleton of the cyclic group is preferably 4 to 7, and more preferably 5 to 6. That is, the cyclic group is preferably a 4-7 membered ring, more preferably a 5-6 membered ring. Specific examples of the monocyclic group include ring structures such as piperidine, pyrrolidine, morpholine, pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, and piperazine. And a group obtained by removing a hydrogen atom from —NH— of a heterocyclic monocyclic compound having —NH—.
When it is polycyclic, the cyclic group is preferably bicyclic, tricyclic or tetracyclic, and the number of atoms constituting the skeleton of the cyclic group is 7-12. 7-10 are more preferable. Specific examples of the polycyclic nitrogen-containing heterocyclic group include heteropolycyclic compounds having —NH— in the ring structure, such as indole, isoindole, carbazole, benzimidazole, indazole, and benzotriazole. A group obtained by removing a hydrogen atom from NH- is exemplified.
The cyclic group may have a substituent. Examples of the substituent include those similar to those exemplified as the substituent for substituting the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group.
As the cyclic group formed by R ¹ and R ² bonded to each other and the adjacent nitrogen atom, a group represented by the following general formula (II) is particularly preferable.

［式中、Ｒ^５およびＲ^６はそれぞれ独立に水素原子またはアルキル基であり；Ｒ^７は、炭素原子が酸素原子または窒素原子で置換されていてもよく、水素原子が置換基で置換されていてもよい炭素数１〜３の直鎖状のアルキレン基である。］

[Wherein, R ⁵ and R ⁶ each independently represents a hydrogen atom or an alkyl group; R ⁷ represents a carbon atom optionally substituted with an oxygen atom or a nitrogen atom, and a hydrogen atom substituted with a substituent It is a C1-C3 linear alkylene group. ]

In formula (II), examples of the alkyl group for R ⁵ and R ⁶ include the same alkyl groups as those described above for the aliphatic hydrocarbon group for R ¹ and R ² , and are linear or branched. And an alkyl group is preferred, and a methyl group is particularly preferred.
In R ⁷ , the alkylene group in which the carbon atom may be substituted with an oxygen atom or a nitrogen atom includes, for example, —CH ₂ —, —CH ₂ —O—, —CH ₂ —NH—, —CH ₂ —CH. _{2 -, - CH 2 -O-} CH 2 -, - CH 2 -NH-CH 2 -, - CH 2 -CH 2 -CH 2 -, - CH 2 -CH 2 -O-CH 2 -, - CH 2 -CH ₂ -NH-CH ₂ -, and the like.
Examples of the substituent for substituting the hydrogen atom of the alkylene group include the same groups as those described above as the substituent for substituting the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group. The hydrogen atom substituted with the substituent may be a hydrogen atom bonded to a carbon atom or a hydrogen atom bonded to a nitrogen atom.

In formula (C1), R ³ is a monovalent photofunctional group.
As used herein, the “photo functional group” refers to a group that absorbs the exposure energy of the exposure performed in step (3).
The photofunctional group is preferably a ring-containing group, which may be a hydrocarbon ring or a heterocyclic ring, preferably a group having the ring structure described for R ¹ and R ² above, or other aromatic ring A group having Specific examples of the ring skeleton of the ring-containing group include benzene, biphenyl, indene, naphthalene, fluorene, anthracene, phenanthrene, xanthone, thioxanthone, and anthraquinone.
These ring skeletons may have a substituent, and the substituent is particularly preferably a nitro group from the viewpoint of base generation efficiency.

  As (C1) component, what is chosen from the compound represented by either the following general formula (C1-11) or (C1-12) is especially preferable.

［式中、Ｒ^４ａ〜Ｒ^４ｂはそれぞれ独立に置換基を有していてもよいベンゼン、ビフェニル、インデン、ナフタレン、フルオレン、アントラセン、フェナントレン、キサントン、チオキサントンおよびアントラキノンから選ばれる環骨格であり、Ｒ^１ａおよびＲ^２ａはそれぞれ独立に炭素数１〜１５のアルキル基またはシクロアルキル基であり、Ｒ^１１ａは炭素数１〜５のアルキル基であり、ｍ”は０または１であり、ｎ”は０〜３であり、ｐ”はそれぞれ０〜３である。］

[Wherein, R ^{4a to} R ^4b each independently represent a ring skeleton selected from benzene, biphenyl, indene, naphthalene, fluorene, anthracene, phenanthrene, xanthone, thioxanthone and anthraquinone, which may have a substituent, and R ^1a and R ^2a are each independently an alkyl group or cycloalkyl group having 1 to 15 carbon atoms, R ^11a is an alkyl group having 1 to 5 carbon atoms, m ″ is 0 or 1, and n ″ is 0. -3 and p "is 0-3 each.]

In formulas (C1-11) and (C1-12), R ^{4a to} R ^4b preferably have a nitro group as a substituent from the viewpoint of base generation efficiency, and particularly preferably substituted at the ortho position.
R ^1a and R ^2a are each preferably a cycloalkyl group having 5 to 10 carbon atoms from the viewpoint of controlling the diffusion length of the generated base.
m ″ is preferably 1. n ″ is preferably 0-2. p ″ is preferably 0 or 1.

  Specific examples of the component (C1) are shown below.

Moreover, as a suitable thing in (C) component, the compound (henceforth "(C2) component") represented by the following general formula (C2) is also mentioned.
The component (C2) absorbs exposure energy by exposure in the step (3), and then the (—CH═CH—C (═O) —) moiety isomerizes to a cis isomer, and further cyclized by heating, (NHR ¹ R ² ) is produced.
The component (C2) is preferable because it is easy to obtain a hardly-solubilizing effect with respect to an alkaline developer in step (5) together with generation of a base.

［式（Ｃ２）中、Ｒ^１及びＲ^２は、上記式（Ｃ１）中のＲ^１及びＲ^２と同様であり、Ｒ^３’はオルト位に水酸基を有する芳香族環式基である。］

Wherein (C2), ^{R 1} and ^{R 2} are the same as ^{R 1} and ^{R 2} in the formula (C1), ^{R 3} 'is an aromatic cyclic group having a hydroxyl group in the ortho position. ]

In the formula (C2), R ¹ and R ² are preferably bonded to each other to form a cyclic group represented by the formula (II) together with an adjacent nitrogen atom. Alternatively, R ¹ and R ² are preferably the same as R ^1a and R ^2a in formula (C1-12).
Examples of the aromatic cyclic group for R ³ ′ include the same groups as those having the aromatic ring exemplified for R ³ in the above formula (C1), and examples of the ring skeleton include benzene, biphenyl, indene, naphthalene, and fluorene. , Anthracene and phenanthrene are preferable, and a benzene ring is more preferable.
The aromatic cyclic group for R ³ ′ may have a substituent other than the hydroxyl group at the ortho position. Examples of the substituent include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, Examples thereof include monovalent organic groups such as nitro group, nitroso group, sulfino group, sulfo group, sulfonate group, phosphino group, phosphinyl group, phosphono group, phosphonate group, amino group, ammonio group, and other alkyl groups.

  Specific examples of the component (C2) are shown below.

Moreover, as a suitable thing in (C) component, the compound (henceforth "(C3) component") represented by the following general formula (C3) is also mentioned.
The component (C3) absorbs exposure energy by exposure in the step (3), decarboxylates, and then reacts with water to produce an amine (base).

［式中、Ｒ^ａおよびＲ^ｄは、水素原子または置換基を有していてもよい炭素数１〜３０の炭化水素基であり（ただし、Ｒ^ａおよびＲ^ｄがともに置換基を有していてもよい炭素数１〜３０の炭化水素基である場合は、互いに結合して環を形成するものとし）；Ｒ^ｂは置換基を有していてもよいアリール基または脂肪族環式基である。］

[Wherein, R ^a and R ^d are each a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent (provided that both R ^a and R ^d have a substituent) In the case of an optionally substituted hydrocarbon group having 1 to 30 carbon atoms, they are bonded to each other to form a ring); and R ^b is an aryl group or an aliphatic cyclic group which may have a substituent. is there. ]

In the formula (C3), R ^a is a hydrogen atom or 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 for ^Ra 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 3, and particularly preferably 1 to 2.
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 a substituent of the aromatic hydrocarbon group include an alkyl group having 1 to 5 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. And a group in which part or all of the hydrogen atoms are substituted with the halogen atoms.

The aliphatic hydrocarbon group for R ^a in the formula (C3) 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 ^a in the formula (C3), the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted with a substituent containing a hetero atom, and the aliphatic hydrocarbon group A part or all of the hydrogen atoms constituting the hydrocarbon group may be substituted with a substituent containing a hetero atom.
The “heteroatom” in R ^a in the formula (C3) 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, decanyl 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 cyclic aliphatic hydrocarbon group (aliphatic cyclic group) in R ^a in the formula (C3) is an aliphatic cyclic group having 3 to 30 carbon atoms which may have a substituent.
In R ^a in the formula (C3), the aliphatic cyclic group may be substituted with a substituent containing a hetero atom in a part of carbon atoms constituting the aliphatic cyclic group. A part or all of the hydrogen atoms constituting the cyclic group may be substituted with a substituent containing a hetero atom.
The “heteroatom” in R ^a in the formula (C3) 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 carbon atoms include, for example, —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 or an acyl group), —S—, —S (═O) ₂ —, —S (═O) ₂ —O— and the like. These substituents may be contained 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.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is 3 to 30, preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms have been removed from a monocycloalkane; a group in which one 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 one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; 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).

［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 —, and 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 above 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 has 1 to 5 carbon atoms, and 1 to 3 Preferably there is.
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 —, Alkylethylene groups such as —CH (CH ₂ CH ₃ ) CH ₂ —; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; —CH (CH ₃ ) CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} - alkyl trimethylene group and the like; Toramechiren group _{[-CH 2 CH 2 CH 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; penta And methylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like.

In these aliphatic cyclic groups, 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.

As the aliphatic cyclic group which may have a substituent of R ^a in the formula (C3), a polycyclic aliphatic cyclic group which may have a substituent is preferable. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, and groups represented by the above (L2) to (L6) and (S3) to (S4). Etc. are preferred.

When R ^a in the formula (C3) is an optionally substituted hydrocarbon group having 1 to 30 carbon atoms, it may form a ring with an adjacent carbon atom. The ring formed may be monocyclic or polycyclic. The number of carbon atoms is preferably 5-30 (including bonded carbon atoms), more preferably 5-20.
Specifically, (regarded as part carbon atom bonded even ring) of the cyclic aliphatic hydrocarbon group in R ^a as described above (aliphatic cyclic group), of 5 to 30 carbon atoms aliphatic ring And a formula group.

R ^a in the formula (C3) is preferably ^a hydrogen atom or a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, or an aliphatic cyclic 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. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, and groups represented by the above (L2) to (L6) and (S3) to (S4). Etc. are preferred.
As the aromatic hydrocarbon group which may have a substituent, a naphthyl group which may have a substituent or a phenyl group which may have a substituent is more preferable.

Examples of the aryl group in R ^b in the formula (C3) include those obtained by removing the arylalkyl group from those exemplified as the aromatic hydrocarbon group in R ^a in the formula (C3). The aryl group for R ^b is more preferably a phenyl group.
The aliphatic cyclic group for R ^b in the formula (C3) is the same as the aliphatic cyclic group for R ^a in the formula (C3). The aliphatic cyclic group for R ^b is preferably an aliphatic polycyclic group, more preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and particularly preferably one or more groups from adamantane. A group excluding a hydrogen atom.
Examples of the substituent that the aromatic hydrocarbon group or aliphatic cyclic group represented by R ^b may have the same substituents as those exemplified for R ^a in the formula (C3).

Examples of R ^d in the formula (C3) include the same as R ^a in the formula (C3).
R ^d in the formula (C3) is preferably a cyclic group which may have a substituent. 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 aromatic hydrocarbon group that may be used.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, and groups represented by the above (L2) to (L6) and (S3) to (S4). Etc. are preferred.
R ^d in the formula (C3) is more preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent, and a phenyl group which may have a substituent. Most preferred.

When R ^a and R ^d in the formula (C3) are both a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent, they are bonded to each other to form a ring. The ring formed may be monocyclic or polycyclic. 5-30 are preferable and carbon number is more preferable including the carbon atom which ^Ra and ^Rd couple | bonded in the said formula (C3).
Specifically, in the formula (C3), the carbon atom to which R ^a and R ^d are bonded is also considered to be a part of the formed ring, and the cyclic aliphatic hydrocarbon group in R ^a described above ( Among the aliphatic cyclic groups, an aliphatic cyclic group having 5 to 30 carbon atoms can be mentioned.

  Specific examples of the component (C3) are shown below.

  Moreover, the thing (C4) containing an acyloxyimino group shown below as a suitable thing in (C) component is mentioned.

［式中、Ｒ^１１、Ｒ^１２、Ｒ^４３、Ｒ^４４はそれぞれ独立に水素原子又は炭素数１〜５のアルキル基を表し、ｎ７〜ｎ１０はそれぞれ独立に０〜３である。］

[Wherein, R ¹¹ , R ¹² , R ⁴³ and R ⁴⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and n7 to n10 each independently represent 0 to 3. ]

Moreover, what was proposed as a photobase generator for chemical amplification resists can be used as (C) component other than what was illustrated above.
Examples of such a photobase generator include ionic ones (anion-cation complex), triphenylsulfonium compounds, triphenylmethanol; photoactive carbamates such as benzyl carbamate and benzoin carbamate; o-carbamoyl hydroxylamide, o -Amides such as carbamoyloxime, aromatic sulfonamide, alpha-lactam and N- (2-allylethynyl) amide; oxime ester, α-aminoacetophenone, cobalt complex, etc .; those described in JP-A-2007-279493 Etc.

(C) A component may be used individually by 1 type and may be used in combination of 2 or more type.
Among the above, as the component (C), the component (C1) is more preferable. Further preferred.
In the resist composition, the content of the component (C) is preferably 0.05 to 50 parts by mass, more preferably 1 to 30 parts by mass, and particularly preferably 5 to 20 parts by mass with respect to 100 parts by mass of the component (A). preferable. When the content of the component (C) is at least the lower limit value, the remaining film property of the exposed portion of the resist film becomes better, and the effects of the present invention are further improved. On the other hand, when the content of the component (C) is not more than the upper limit value, the transparency of the resist film can be maintained.

<Acid compound component; component (G)>
In the present invention, as the component (G),
An acidic salt (hereinafter referred to as “(G1) component”) having an acid strength capable of increasing the solubility of the base component (A) in an alkaline developer, or
An acid other than an acidic salt (one that does not form a salt, one that is not ionic; hereinafter referred to as “component (G2)”) can be used.
The “having acid strength capable of increasing the solubility of the base component (A) in an alkaline developer” means, for example, when the polymer compound (A1) having the structural unit (a1) is used, By including baking (PEB) in 4), an acid capable of cleaving at least some of the bonds in the structure of the acid-decomposable group in the structural unit (a1) is included.

[(G1) component]
Examples of the component (G1) include ionic compounds (salt compounds) composed of a nitrogen-containing cation and a counter anion. Even when the component (G1) is in the form of a salt, the component (G1) itself has acidity and acts as a proton donor.
Hereinafter, the cation part and the anion part of the component (G1) will be described respectively.

(Cation part of component (G1))
The cation part of (G1) component will not be specifically limited if it contains a nitrogen atom, For example, the cation represented by the following general formula (G1c-1) is mentioned suitably.

［式中、Ｒ^１０１ｄ、Ｒ^１０１ｅ、Ｒ^１０１ｆ、Ｒ^１０１ｇはそれぞれ水素原子、炭素数１〜１２の直鎖状、分岐鎖状もしくは環状のアルキル基、アルケニル基、オキソアルキル基もしくはオキソアルケニル基、炭素数６〜２０のアリール基若しくはアリールアルキル基、炭素数７〜１２のアラルキル基、又はアリールオキソアルキル基を示し、これらの基の水素原子の一部又は全部がハロゲン原子、アルコキシ基、又は硫黄原子によって置換されていてもよい。Ｒ^１０１ｄとＲ^１０１ｅ、又は、Ｒ^１０１ｄとＲ^１０１ｅとＲ^１０１ｆは、これらが結合して式中の窒素原子と共に環を形成してもよく、環を形成する場合には、Ｒ^１０１ｄとＲ^１０１ｅ、又は、Ｒ^１０１ｄとＲ^１０１ｅとＲ^１０１ｆは、それぞれ炭素数３〜１０のアルキレン基であるか、又は式中の窒素原子を環の中に有する複素芳香族環を形成する。］

[Wherein, R ^101d , R ^101e , R ^101f and R ^101g are each a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an alkenyl group, an oxoalkyl group or an oxoalkenyl group, An aryl group or arylalkyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aryloxoalkyl group, wherein some or all of the hydrogen atoms of these groups are halogen atoms, alkoxy groups, or sulfur It may be substituted by an atom. R ^101d and R ^101e , or R ^101d and R ^101e and R ^101f may combine to form a ring together with the nitrogen atom in the formula, and in the case of forming a ring, R ^101d and R ^101e Alternatively, R ^101d , R ^101e, and R ^101f are each an alkylene group having 3 to 10 carbon atoms, or form a heteroaromatic ring having a nitrogen atom in the formula in the ring. ]

In formula (G1c-1), R ^101d , R ^101e , R ^101f , and R ^101g each represent a hydrogen atom, a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, an alkenyl group, or an oxoalkyl group. Group or an oxoalkenyl group, an aryl group or arylalkyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, or an aryloxoalkyl group.
^Examples of the alkyl group of R ^{101d to} R ^101g include the same groups as the alkyl groups of R ¹ and R ² described above. The number of carbon atoms is preferably 1 to 10, and a methyl group, an ethyl group, or a propyl group. Or a butyl group is particularly preferred.
The alkenyl group of R ^{101d to} R ^101g preferably has 2 to 10 carbon atoms, more preferably 2 to 5 and even more preferably 2 to 4. Specific examples include a vinyl group, a propenyl group (allyl group), a butynyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group.
The oxoalkyl group of R ^{101d to} R ^101g preferably has 2 to 10 carbon atoms, and examples thereof include a 2-oxoethyl group, a 2-oxopropyl group, a 2-oxocyclopentyl group, and a 2-oxocyclohexyl group. .
^{Examples of the oxoalkenyl} group of R ^{101d to} R ^101g include an oxo-4-cyclohexenyl group and a 2-oxo-4-propenyl group.
Examples of the aryl group of R ^{101d to} R ^101g include the same aryl groups as those in the aromatic hydrocarbon groups of R ¹ and R ² described above, and a phenyl group or a naphthyl group is preferable. Examples of the arylalkyl group include those in which one or more hydrogen atoms in the aryl group are substituted with an alkyl group (preferably an alkyl group having 1 to 5 carbon atoms).
^Examples of the aralkyl group and aryloxoalkyl group represented by R ^{101d to} R ^101g include a benzyl group, a phenylethyl group, a phenethyl group, a 2-phenyl-2-oxoethyl group, and a 2- (1-naphthyl) -2-oxoethyl group. , 2- (2-naphthyl) -2-oxoethyl group and the like.

A hydrogen atom in the alkyl group, alkenyl group, oxoalkyl group, oxoalkenyl group, aryl group, arylalkyl group, aralkyl group, aryloxoalkyl group of R ^{101d to} R ^101g is a halogen atom such as a fluorine atom, an alkoxy group, Alternatively, it may be substituted with a sulfur atom or not.
When R ^{101d to} R ^101g are composed of only a combination of an alkyl group and a hydrogen atom, at least a part of the hydrogen atom of the alkyl group is substituted with a halogen atom such as a fluorine atom, an alkoxy group, or a sulfur atom. It is preferable in terms of storage stability and lithography properties.

R ^101d and R ^101e , or R ^101d , R ^101e, and R ^101f may combine to form a ring together with the nitrogen atom in the formula. Examples of the ring formed include a piperidine ring, hexamethyleneimine ring, azole ring, pyridine ring, pyrimidine ring, azepine ring, pyrazine ring, quinoline ring, and benzoquinoline ring.
Further, the ring skeleton may contain an oxygen atom, and specific examples thereof include an oxazole ring and an isoxazole ring.

Especially, as a cation part represented by the said formula (G1c-1), the nitrogen-containing cation whose pKa is 7 or less is preferable.
In the present invention, pKa is an acid dissociation constant, and is generally used as an index indicating the acid strength of a target substance. The pKa value of the cation of the component (G1) can be determined by measuring by a conventional method. It can also be estimated by calculation using known software such as “ACD / Labs” (trade name, manufactured by Advanced Chemistry Development).
The pKa of the component (G1) is preferably 7 or less, and can be appropriately determined according to the type of the counter anion and the pKa so as to be a relatively weak base with respect to the counter anion. Is preferably pKa-2 to 7, more preferably -1 to 6.5, and still more preferably 0 to 6. By making pKa below the upper limit of the above range, the basicity of the cation can be made sufficiently weak, and the component (G1) itself can be an acidic compound. Moreover, by making pKa more than the lower limit of the said range, it is easy to form a salt with a counter anion, the acidity of (G1) component can be made moderate, and (G1) component is too acidic. Therefore, it is possible to prevent the storage stability from being deteriorated.
As the cation satisfying the pKa, a cation represented by any one of the following general formulas (G1c-11) to (G1c-13) is particularly preferable.

［式中、Ｒｆ^ｇ１は炭素数１〜１２のフッ素化アルキル基である。Ｒｎ^ｇ１、Ｒ^ｇ２はそれぞれ独立に水素原子または炭素数１〜５のアルキル基であり、Ｒｎ^ｇ１とＲ^ｇ２とは互いに環を形成していてもよい。Ｑ^ａ〜Ｑ^ｃはそれぞれ独立に炭素原子又は窒素原子であり、Ｒｎ^ｇ３は水素原子またはメチル基である。Ｒｎ^ｇ４、Ｒｎ^ｇ５はそれぞれ独立に芳香族炭化水素基または炭素数１〜５のアルキル基である。Ｒ^ｇ１、Ｒ^ｇ２はそれぞれ独立に炭化水素基である。ｎ１５、ｎ１６はそれぞれ０〜４の整数である。ｎ１５、ｎ１６が２以上の場合、隣接する炭素原子の水素原子を置換する複数のＲ^ｇ１、Ｒ^ｇ２は結合して環を形成していてもよい。］

[ ^Wherein , Rf ^g1 represents a fluorinated alkyl group having 1 to 12 carbon atoms. Rn ^g1 and R ^g2 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and Rn ^g1 and R ^g2 may form a ring with each other. Q ^{a to} Q ^c are each independently a carbon atom or a nitrogen atom, and ^Rng3 is a hydrogen atom or a methyl group. Rn ^g4 and Rn ^g5 are each independently an aromatic hydrocarbon group or an alkyl group having 1 to 5 carbon atoms. R ^g1 and R ^g2 are each independently a hydrocarbon group. n15 and n16 are each an integer of 0 to 4. When n15 and n16 are 2 or more, a plurality of R ^g1 and R ^g2 substituting for hydrogen atoms of adjacent carbon atoms may be bonded to form a ring. ]

In Formula (G1c-11), Rf ^g1 is a fluorinated alkyl group having 1 to 12 carbon atoms, and a fluorinated alkyl group having 1 to 5 carbon atoms in which 50% or more of the hydrogen atoms in the alkyl group are fluorinated. It is preferable that
In formula (G1c-11), Rn ^g1 and Rn ^g2 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and the alkyl group described above in (G1c-1) Among these, it is the same as that of C1-C5. Further, when both Rn ^g1 and Rn ^g2 are alkyl groups, the alkyl groups of Rn ^g1 and Rn ^g2 may be bonded to each other to form a ring together with NH ^{+ in} the formula.
In formula (G1c-13), Rn ^g4 and Rn ^g5 each independently represent an aromatic hydrocarbon group or an alkyl group having 1 to 5 carbon atoms. The aromatic hydrocarbon group and the alkyl group are the same as the aryl group and the alkyl group having 1 to 5 carbon atoms exemplified in the description of R ^101d , R ^101e , R ^101f , and R ^101g in (G1c-1), respectively. Can be mentioned.
In formulas (G1c-12) to (G1c-13), n15 and n16 are integers of 0 to 4, preferably 0 to 2, and more preferably 0.
In formulas (G1c-12) to (G1c-13), R ^g1 and R ^g2 are each independently a hydrocarbon group, preferably an alkyl group or an alkenyl group having 1 to 12 carbon atoms. The alkyl group and alkenyl group are the same as those described in the above formula (G1c-1).
When n15 and n16 are 2 or more, the plurality of R ^g1 and R ^g2 may be the same or different. Moreover, when n15 and n16 are 2 or more, a plurality of R ^g1 and R ^g2 substituting for hydrogen atoms of adjacent carbon atoms may be bonded to form a ring. Examples of the ring to be formed include a benzene ring and a naphthalene ring. That is, the compound represented by any one of formulas (G1c-12) to (G1c-13) may be a condensed ring compound formed by condensing two or more rings.

  Specific examples of the compounds represented by any of the above formulas (G1c-11) to (G1c-13) are shown below.

(Anion part of component (G1))
The anion portion of the component (G1) is not particularly limited, and can be appropriately selected from the anion portions of salts usually used in resist compositions.
In particular, as the anion part of the component (G1), when the salt is formed with the cation part of the component (G1) to form the component (G1), the component (G1) is alkali-developed with the component (A). It is preferable that the solubility in the liquid can be increased.
Here, “the solubility of the component (A) in an alkaline developer can be increased” means that, for example, when the component (A1) having the structural unit (a1) is used, baking is performed in the step (4). Means that at least a part of the bonds in the structure of the acid-decomposable group in the structural unit (a1) can be cleaved.
That is, the anion portion of (G1) is preferably strongly acidic. Specifically, the pKa of the anion moiety is more preferably 0 or less, further preferably pKa-15 to -1, and particularly preferably -13 to -3. When the pKa of the anion moiety is 0 or less, the acidity of the anion can be sufficiently strong against cations of pKa7 or less, and the component (G1) itself can be an acidic compound. On the other hand, by setting the pKa of the anion portion to −15 or more, it is possible to prevent deterioration in storage stability due to the excessively acidic component (G1).

As the anion part of the component (G1), at least one anion group selected from the group consisting of a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methide anion is used. What has is preferable.
Specifically, for example, the general formula “R ⁴ ” SO ₃ ^— (R ⁴ ”represents a linear, branched or cyclic alkyl group, halogenated alkyl group, aryl which may have a substituent. An anion represented by a group or an alkenyl group.

In the general formula “R ⁴ ″ SO ₃ ⁻ ”, R ⁴ ″ represents a linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl which may have a substituent. Represents a group.

The linear or branched alkyl group as R ⁴ ″ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 1 to 4 carbon atoms. Most preferred.
The cyclic alkyl group as R ⁴ ″ preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of “R ⁴ ″ SO ₃ ⁻ ” when R ⁴ ″ is an alkyl group include methane sulfonate, n-propane sulfonate, n-butane sulfonate, n-octane sulfonate, 1-adamantane sulfonate, 2-norbornane sulfonate, Examples thereof include alkyl sulfonates such as d-camphor-10-sulfonate.

The halogenated alkyl group as R ⁴ ″ is one in which part or all of the hydrogen atoms in the alkyl group are substituted with halogen atoms, and the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, Among them, a linear or branched alkyl group is more preferable, and it is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a tert-pentyl group, or an isopentyl group. More preferable examples of the halogen atom substituted with a hydrogen atom include a fluorine atom, a chlorine atom, an iodine atom, a bromine atom, etc. In a halogenated alkyl group, a hydrogen atom of an alkyl group (an alkyl group before halogenation) It is preferable that 50 to 100% of all the hydrogen atoms are substituted with halogen atoms, and all the hydrogen atoms are substituted with halogen atoms. It is more preferable to have.
Here, the halogenated alkyl group is preferably a fluorinated alkyl group. The fluorinated alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
Further, the fluorination rate of the fluorinated alkyl group is preferably 10 to 100%, more preferably 50 to 100%. Particularly, when all the hydrogen atoms are substituted with fluorine atoms, the strength of the acid is increased. preferable.
Specific examples of such a preferred fluorinated alkyl group include a trifluoromethyl group, a heptafluoro-n-propyl group, and a nonafluoro-n-butyl group.

The aryl group as R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group as R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.

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

In the group represented by X ³ —Q′—, Q ′ is a divalent linking group containing an oxygen atom.
Q ′ may contain atoms other than oxygen atoms. 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. A sulfonyl group (—SO ₂ —) may be further linked to the combination.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) —, —SO _2- O—R ⁹⁴ —O—C (═O) —, —R ⁹⁵ —SO ₂ —O—R ⁹⁴ —O—C (═O) — (wherein R ^{91 to} R ⁹⁵ are each independently alkylene. Group.) And the like.
The alkylene group for R ^{91 to} R ⁹⁵ 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 ′ is preferably a divalent linking group containing an ester bond or an ether bond, and among them, —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'-, the hydrocarbon group of ^{X 3,} the same as the C1-30 hydrocarbon group ^{R a} in the formula (C3) may be mentioned.
Among them, X ³ may have a substituent a straight chain alkyl group, or, it is preferable to 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 any one of the formulas (L2) to (L6) and (S3) to (S4). A group represented by the formula is preferred.

Among the above, R ⁴ ″ preferably has a halogenated alkyl group or X ³ -Q′— as a substituent.
In the case of having X ³ -Q′- as a substituent, R ⁴ ″ is X ³ -Q′-Y ^3- [wherein Q ′ and X ³ are the same as defined above, and Y ³ represents a substituent. A C1-C4 alkylene group which may have or a C1-C4 fluorinated alkylene group which may have a substituent.] Is preferable.
In the group represented by X ³ -Q′—Y ³ —, the alkylene group for Y ³ includes the same alkylene groups as those described above for Q ′ 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 ^3, _{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 -, - C H 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 ³ 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.

R ⁴ "is ^{X 3 -Q'-Y} 3 - is a group represented by ^R 4" SO ₃ ^- Examples of, for example anion represented by any one of the following formulas (b1) ~ (b9) Is mentioned.

［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、ｇは１〜２０の整数であり、Ｒ^７は置換基であり、ｎ１〜ｎ６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] G is an integer of 1 to 20, R ⁷ is a substituent, n1 to n6 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.]

Examples of the substituent for R ⁷ include the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in R ^a in the formula (C3). The same thing 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 anion part of (G1) component, the anion represented, for example by the following general formula (G1a-3) and the anion represented by the following general formula (G1a-4) are mentioned as a preferable thing.

［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

In the formula (G1a-3), 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 preferably has 2 to 6 carbon atoms. More preferably 3 to 5 carbon atoms, most preferably 3 carbon atoms.
In formula (G1a-4), Y ″ and Z ″ each independently represent a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the carbon number of the alkyl group Is preferably 1 to 10, more preferably 1 to 7 carbon atoms, and most preferably 1 to 3 carbon atoms.
The number of carbon atoms of the X ″ alkylene group or the number of carbon atoms of the Y ″ and Z ″ alkyl groups is preferably as small as possible because the solubility in a resist solvent is good within the above-mentioned range of carbon numbers.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms 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 fluorination rate of the alkylene group or alkyl group is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkylene group or a perfluoroalkylene group in which all hydrogen atoms are substituted with fluorine atoms. A fluoroalkyl group;

The anion moiety of the component (G1) is an anion represented by the above formula “R ⁴ ” SO ₃ ⁻ ”(in particular, R ⁴ ” is a group represented by “X ³ -Q′-Y ³ —”). An anion represented by any one of the above formulas (b1) to (b9) or an anion represented by the above formula (G1a-3) is particularly preferable.

As the component (G1), one type may be used alone, or two or more types may be used in combination.
In the resist composition, the content ratio of the component (G1) in the component (G) is preferably 40% by mass or more, more preferably 70% by mass or more, and may be 100% by mass. When the content ratio of the component (G1) is not less than the lower limit of the above range, the storage stability and the lithography characteristics are excellent.
Moreover, 0.5-30 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (G1) component in a resist composition, 1-20 mass parts is more preferable, 2-15 mass parts Is more preferable. When the content of the component (G1) is in the above range, the lithography properties are excellent.

[(G2) component]
The component (G2) does not correspond to the component (G1), and the component (G2) itself has an acidity and acts as a proton donor. Examples of such component (G2) include nonionic acids that do not form a salt.
The component (G2) is not particularly limited as long as it is an acid having an acid strength capable of increasing the solubility of the base component (A) in an alkaline developer, but is suitable among the components (G2). For example, an imine acid or a sulfonic acid compound is preferred because the reactivity with the acid dissociable group of the base component and the solubility of the resist film in an alkaline developer are likely to increase. , Bis (alkylsulfonyl) imide, tris (alkylsulfonyl) methide, or those having a fluorine atom.
In particular, a compound represented by any one of the following general formulas (G2-1) to (G2-3) (in particular, a compound represented by the general formula (G2-2) is preferable), the above-described general formula (b1) to A compound in which “—SO ₃ ^— ” of the anion represented by any one of (b9) is changed to “—SO ₃ H”, an anion represented by the aforementioned general formula (G1a-3) or (G1a-4) Of these, compounds in which “N ⁻ ” is “NH”, camphorsulfonic acid, and the like are preferable. Other examples include acid components such as fluorinated alkyl group-containing carboxylic acids, higher fatty acids, higher alkyl sulfonic acids, and higher alkyl aryl sulfonic acids.

［式（Ｇ２−１）中、ｗ’は１〜５の整数である。式（Ｇ２−２）中、Ｒ^ｆは水素原子又はアルキル基（ただし、当該アルキル基中の水素原子の一部若しくは全部がフッ素原子、水酸基、アルコキシ基、カルボキシ基又はアミノ基のいずれかにより置換されていてもよい）を示し、ｙ’は２〜３の整数である。式（Ｇ２−３）中、Ｒ^ｆは前記と同じであり、ｚ’は２〜３の整数である。］

[In Formula (G2-1), w ′ is an integer of 1 to 5. In formula (G2-2), R ^f represents a hydrogen atom or an alkyl group (however, part or all of the hydrogen atoms in the alkyl group are substituted with any of a fluorine atom, a hydroxyl group, an alkoxy group, a carboxy group, or an amino group) Y ′ is an integer of 2 to 3. In formula (G2-3), R ^f is the same as described above, and z ′ is an integer of 2 to 3. ]

Examples of the compound represented by the formula (G2-1) include (C ₄ F ₉ SO ₂ ) ₂ NH and (C ₃ F ₇ SO ₂ ) ₂ NH.

In the formula (G2-2), the number of carbon atoms of the alkyl group in R ^f is preferably 1 to 2, and more preferably 1.
As the alkoxy group in which the hydrogen atom in the alkyl group may be substituted, a methoxy group and an ethoxy group are preferable.
Examples of the compound represented by the formula (G2-2) include a compound represented by the following chemical formula (G2-21).

In the formula (G2-3), the ^{R f,} is the same as ^{R f} in formula (G2-2).
Examples of the compound represented by the formula (G2-3) include a compound represented by the following chemical formula (G2-31).

Examples of the fluorinated alkyl group-containing carboxylic acid include C ₁₀ F ₂₁ COOH.
Examples of higher fatty acids include higher fatty acids having an alkyl group having 8 to 20 carbon atoms, and specific examples include dodecanoic acid, tetradecanoic acid, and stearic acid.
The alkyl group having 8 to 20 carbon atoms may be linear or branched, and a phenylene group or an oxygen atom may be interposed in the chain, or hydrogen in the alkyl group. A part of the atoms may be substituted with a hydroxyl group or a carboxy group.

Examples of the higher alkyl sulfonic acid include sulfonic acids having an alkyl group with an average carbon number of preferably 9 to 21, more preferably 12 to 18, and specific examples include decane sulfonic acid, dodecane sulfonic acid, and tetradecane sulfonic acid. , Pentadecane sulfonic acid, stearic acid sulfonic acid and the like.
Examples of the higher alkylaryl sulfonic acid include alkylbenzene sulfonic acid and alkyl naphthalene sulfonic acid having an alkyl group with an average carbon number of preferably 6 to 18, more preferably 9 to 15, and specifically, dodecylbenzene sulfone. Examples include acid and decylnaphthalenesulfonic acid.
Examples of other acid components include alkyl diphenyl ether disulfonic acids having an alkyl group with an average carbon number of preferably 6 to 18, more preferably 9 to 15, and specifically dodecyl diphenyl ether disulfonic acid.

In addition, as the component (G2) other than the above, organic carboxylic acids, phosphorus oxo acids and derivatives thereof may also be mentioned.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid. Among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms, and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.

(G) When a component contains (G2) component, (G2) component may be used individually by 1 type, and may be used in combination of 2 or more type. Among the above, as the component (G2), it is possible to use one or more selected from the group consisting of sulfonylimide, bis (alkylsulfonyl) imide, tris (alkylsulfonyl) methide, and those having fluorine atoms. More preferably, it is particularly preferable to use one or more of these fluorine atoms.
When the resist composition contains the component (G2), the content of the component (G2) in the resist composition is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the component (A). -15 mass parts is more preferable, and 1-10 mass parts is further more preferable. When the content of the component (G2) is equal to or higher than the lower limit, the solubility of the resist film in the alkaline developer is likely to increase. On the other hand, when the content of the component (G2) is equal to or lower than the upper limit value, good sensitivity is easily obtained.

<Other ingredients>
In the resist composition used in the resist pattern forming method of the present invention, components other than the components described above, for example, an acid generator component, an acid proliferator component, a fluorine additive (fluorine-containing compound), an amine and the like may be blended. .

[Acid generator component; (B) component]
The component (B), unlike the component (G), generates an acid after exposure in the step (3) and baking (PEB) in the step (4). The component (B) itself does not need to have acidity, and may be any component that decomposes by heat or light and functions as an acid.

The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used.
Examples of such an acid generator include a thermal acid generator that generates an acid by heating, a photoacid generator that generates an acid by exposure, and the like. Agents, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, diazomethane acid generators such as poly (bissulfonyl) diazomethanes, nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, disulfone Various things, such as an acid generator, are known.
These acid generator components are generally known as photoacid generators (PAGs), but also function as thermal acid generators (TAGs). Therefore, as the acid generator component that can be used in the present invention, any of acid generators conventionally known as acid generators for chemically amplified resist compositions can be used.
The “thermal acid generator that generates an acid by heating” is preferably the baking (PEB) temperature in step (3) or less, specifically 200 ° C. or less, more preferably 50 to 150 ° C. Means a component that generates By controlling the temperature to be equal to or lower than the PEB temperature, it becomes easy to control the generation of acid and the deprotection reaction of the base material component at different temperatures. More preferably, when the temperature is 50 ° C. or higher, the stability in the resist composition is improved.

The onium salt acid generator of component (B) is selected from the group consisting of a sulfonate anion, a carboxylate anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, and a tris (alkylsulfonyl) methide anion in the anion portion. Those having at least one kind of anionic group are preferred. More specifically, the same anions as those mentioned in the above (G1) can be mentioned.
Examples of the cation moiety include those represented by the following general formula (b-c1) or general formula (b-c2).

［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.
Moreover, 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.
Regarding R ⁵⁶ ′, specific examples of the aliphatic cyclic group containing a hetero atom in the ring structure include groups represented by the aforementioned formulas (L1) to (L6) and (S1) to (S4). It is done.
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 formula (b-1-42), R ^C represents a substituent. Examples of the substituent include 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 groups, —C (═O) —O—R ⁶ ″, —O—C (═O) —R ⁷ ″, —O—R ⁸ ″).

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.

  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 (exposure) of radiation. It is what you have. 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. ]

［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-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.

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). An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on page ˜85 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.
When the resist composition contains the component (B), the content of the component (B) in the resist composition is 100 parts by weight of the component (A), when the component (B) is a thermal acid generator. 0.5-30 mass parts is preferable, and 1-20 mass parts is more preferable. (B) When a component is a photo-acid generator, 0.5-30 mass parts is preferable, and 1-20 mass parts is more preferable. By setting it within the above range, pattern formation is sufficiently performed. Further, when the content of the component (B) is at least the lower limit value, the solubility of the resist film in an alkaline developer is likely to increase, and the resolution is further improved. On the other hand, it is preferable that it is not more than the upper limit value because the sensitivity becomes good. In the case of a photoacid generator, the transparency of the resist film is improved by setting it to the upper limit value or less.

  When the resist composition contains the component (B), the content ratio of the component (B) with respect to the total of the component (G) and the component (B) is preferably 50% by mass or less, and 20% by mass or more. More preferably.

[Acid Proliferator Component; Component (H)]
In the resist pattern forming method of the present invention, the component (H) is decomposed by an acid to generate a free acid, and the component (H) is further decomposed by the free acid to generate a free acid. In this way, due to the action of the acid, the component (H) is decomposed in a chain manner to generate a large number of free acid molecules.

The component (H) may be any component as long as it decomposes by the action of an acid and newly generates an acid itself to proliferate the acid in an autocatalytic manner. For example, a compound having a crosslinked carbocyclic skeleton structure is suitable. Can be mentioned.
Here, the “compound having a bridged carbocyclic skeleton structure” refers to a compound having a structure (hereinafter sometimes simply referred to as “bridged carbocycle”) formed by a bridge bond between a plurality of carbocycles in the molecule. .
The compound having the bridged carbocyclic skeleton structure has a bridging bond, whereby the molecule is stiffened and the thermal stability of the compound is improved.
The number of carbocycles is preferably 2-6, more preferably 2-3.
In the bridged carbocycle, part or all of the hydrogen atoms may be substituted with an alkyl group, an alkoxy group or the like. As the said alkyl group, C1-C6 is preferable, 1-3 are more preferable, and a methyl group, an ethyl group, a propyl group etc. are mentioned specifically ,. As the said alkoxy group, C1-C6 is preferable, 1-3 are more preferable, and a methoxy group, an ethoxy group, etc. are mentioned specifically ,. Moreover, the bridge | crosslinking carbocycle may have unsaturated bonds, such as a double bond.

  In the present invention, the bridged carbocycle has a hydroxyl group and a sulfonate group represented by the following general formula (Hs) on the carbon atom adjacent to the carbon atom to which the hydroxyl group is bonded. Particularly preferred.

［式中、Ｒ^０は脂肪族基、芳香族基又は複素環式基を示す。］

[Wherein, R ⁰ represents an aliphatic group, an aromatic group or a heterocyclic group. ]

In the formula (Hs), R ⁰ represents an aliphatic group, an aromatic group, or a heterocyclic group.
In R ⁰ , examples of the aliphatic group include a chain or cyclic alkyl group or alkenyl group, and the number of carbon atoms is preferably 1 to 12, and more preferably 1 to 10.
The aromatic group may be a monocyclic group or a polycyclic group, and specific examples thereof include an aryl group.
The heterocyclic group may be a monocyclic group or a polycyclic group, and examples thereof include those derived from various conventionally known heterocyclic compounds.
The above aliphatic group, aromatic group and heterocyclic group may have a substituent, such as a halogen atom, alkyl group, alkoxy group, amino group, substituted amino group, oxygen atom. (= O) and the like.
Specifically as the aliphatic group and the aromatic group, for example, methyl group, ethyl group, propyl group, butyl group, acyl group, hexyl group, vinyl group, propylene group, allyl group, cyclohexyl group, cyclooctyl group, A bicyclo hydrocarbon group, a tricyclo hydrocarbon group, a phenyl group, a tolyl group, a benzyl group, a phenethyl group, a naphthyl group, a naphthylmethyl group, or a substituted product thereof can be exemplified.
Examples of the heterocyclic group include various heterocyclic compounds, for example, 5-membered ring compounds containing one hetero atom such as furan, thiophene, pyrrole, benzofuran, thionaphthene, indole, carbazole, or condensed ring compounds thereof; oxazole, thiazole 5-membered ring compounds containing two heteroatoms such as pyrazole, or condensed ring compounds thereof; 6-membered ring compounds containing one heteroatom such as pyran, pyrone, coumarin, pyridine, quinoline, isoquinoline, acridine, etc. or condensed ring compounds thereof And various derivatives derived from a six-membered ring compound containing two heteroatoms such as pyridazine, pyrimidine, pyrazine, phthalazine or the like, or a condensed ring compound thereof.

In the present invention, when the component (H) has a hydroxyl group and a sulfonate group represented by the general formula (Hs) on the bridged carbocycle, the component (H) is decomposed by the action of an acid. Then, a new acid (R ⁰ SO ₃ H) is generated.
Thus, one acid increases in one reaction, and the reaction proceeds at an accelerated speed as the reaction proceeds, and the component (H) is decomposed in a chain.
In such a case, the strength of the acid generated is preferably 3 or less, and particularly preferably 2 or less, as the acid dissociation constant (pKa). If pKa is 3 or less, the generated acid itself is more likely to induce autolysis. Conversely, if the acid is weaker than this, it is difficult to cause autolysis.
Examples of the acid liberated by the above reaction (R ⁰ SO ₃ H) include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic acid, Cyclohexanesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, 2,2,2-trifluoroethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, p-bromobenzenesulfonic acid, p-nitrobenzenesulfonic acid, 2- Examples thereof include thiophenesulfonic acid, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid and the like.

  As the component (H), more specifically, compounds represented by the following general formulas (H1) to (H4) (hereinafter, compounds corresponding to the respective general formulas are referred to as compounds (H1) to (H4)). ).

［式中、Ｒ^５１は水素原子、脂肪族基又は芳香族基を示し；Ｒ^５２は脂肪族基、芳香族基又は複素環式基を示す。］

[Wherein R ⁵¹ represents a hydrogen atom, an aliphatic group or an aromatic group; R ⁵² represents an aliphatic group, an aromatic group or a heterocyclic group. ]

In the general formulas (H1) to (H3), R ⁵¹ represents a hydrogen atom, an aliphatic group, or an aromatic group. In R ⁵¹ , the aliphatic group and aromatic group are the same as the aliphatic group and aromatic group of R ⁰ described above. R ⁵¹ is preferably an aliphatic group or an aromatic group, more preferably an aliphatic group, particularly preferably a lower alkyl group, and most preferably a methyl group.
In the general formulas (H1) to (H4), R ⁵² represents an aliphatic group, an aromatic group, or a heterocyclic group, and examples thereof include the same as R ⁰ described above. R ⁵² is preferably an aliphatic group or an aromatic group, and more preferably an aliphatic group.

In the compounds (H1) to (H4), the compound (H1) has a crosslinking bond at the 1,3-position of the bicyclo compound, and the compound (H2) and the compound (H3) have a crosslinking bond at the 1,4-position of the bicyclo compound. And the compound (H4) has a cross-linking bond at positions 1 and 6 of the bicyclo compound (decalin).
Therefore, in the compounds (H1) to (H4), the conformational change of the cyclohexane ring is highly suppressed, and the ring structure exhibits rigidity.

  In the component (H), for example, the general formula (Hs) is bonded to a hydroxyl group and a carbon atom adjacent to the carbon atom to which the hydroxyl group is bonded on the bridged carbocycle such as the compounds (H1) to (H4). A compound having a sulfonate group represented by the above is easily synthesized by allowing a sulfonic acid halide to act on a diol compound. This diol compound has two isomers, cis and trans. The cis isomer is more thermally stable and is preferably used. In addition, the compound can be stably stored as long as no acid is present.

  Preferred specific examples of the component (H) are listed below.

  As the component (H), among the above, the compound (H1) or the compound (H2) is preferable and the compound (H1) is more preferable because the effects of the present invention are good. Specifically, it is preferable to use at least one selected from the compounds represented by the chemical formulas (H1-1) to (H1-9), and the compound represented by the chemical formula (H1-9) is the most preferable. preferable.

As the component (H), one type may be used alone, or two or more types may be used in combination.
In the resist composition, the content of the component (H) is preferably 0.1 to 30 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the component (A). When the content of the component (H) is equal to or higher than the lower limit, the resolution is further improved. On the other hand, when the content of the component (H) is not more than the upper limit value, the sensitivity becomes better.

When the component (H) and the component (G) are used in combination, the mixing ratio of the component (H) and the component (G) is preferably 9: 1 to 1: 9 in terms of molar ratio, 5: 5 is more preferable, and 9: 1 to 6: 4 is particularly preferable. When the ratio of the component (H) is equal to or greater than the lower limit of the above range, the resolution is further improved. On the other hand, when the ratio of the component (H) is equal to or lower than the upper limit of the above range, the sensitivity becomes better.
Moreover, when using together (H) component and (B) component, it is preferable that the mixing ratio of (H) component and (B) component is 9: 1 to 1: 9 by molar ratio, 9: It is more preferably 1 to 5: 5, and particularly preferably 9: 1 to 6: 4. When the ratio of the component (H) is equal to or greater than the lower limit of the above range, the resolution is further improved. On the other hand, when the ratio of the component (H) is equal to or lower than the upper limit of the above range, the sensitivity becomes better.

[Fluorine additive; component (F)]
The resist composition of the present invention may contain a fluorine additive (hereinafter referred to as “component (F)”) in order to impart water repellency to the resist film.
As the component (F), for example, a fluorine-containing polymer compound described in JP 2010-002870 A can be used.
More specifically, examples of the component (F) include a polymer having a structural unit (f1) represented by the following formula (f1-1). Examples of such a polymer include a polymer consisting of only the structural unit (f1) (homopolymer); a copolymer of the structural unit represented by the following formula (f1) and the structural unit (a1); ), A copolymer of the structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Here, as the structural unit (a1) copolymerized with the structural unit represented by the following formula (f1), the structure represented by the formulas (a1-0-11) to (a1-0-13). A unit is preferable, and the structural unit represented by the formula (a1-1-32) is particularly preferable.

［式中、Ｒは前記同様であり、Ｒ^４５およびＲ^４６はそれぞれ独立して水素原子、ハロゲン原子、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を表し、複数のＲ^４５またはＲ^４６は同じであっても異なっていてもよい。ａ１は１〜５の整数であり、Ｒ^７”はフッ素原子を含む有機基である。］

[Wherein, R is the same as defined above, and R ⁴⁵ and R ⁴⁶ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, The plurality of R ⁴⁵ or R ⁴⁶ may be the same or different. a1 is an integer of 1 to 5, and R ⁷ ″ is an organic group containing a fluorine atom.]

In formula (f1-1), R is the same as described above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of the halogen atom for R ⁴⁵ and R ⁴⁶ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms of R ⁴⁵ and R ⁴⁶ include the same as the alkyl group having 1 to 5 carbon atoms of R, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms of R ⁴⁵ and R ⁴⁶ include 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. Can be mentioned. 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. Especially, as R < ⁴⁵ >, R ^<46 >, a hydrogen atom, a fluorine atom, or a C1-C5 alkyl group is preferable, and a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group is preferable.
In formula (f1-1), a1 is an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

In formula (f1-1), R ⁷ ″ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms. The carbon number of 1 to 10 is particularly preferable.
The hydrocarbon group containing a fluorine atom preferably has 25% or more of the hydrogen atoms in the hydrocarbon group fluorinated, more preferably 50% or more fluorinated, and 60% or more. Fluorination is particularly preferable because the hydrophobicity of the resist film during immersion exposure is increased.
Among these, as R ⁷ ″, a fluorinated hydrocarbon group having 1 to 5 carbon atoms is particularly preferable, and a methyl group, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , —CH (CF ₃ ) ₂ , —CH ₂ —CH ₂ —CF ₃ , —CH ₂ —CH ₂ —CF ₂ —CF ₂ —CF ₂ —CF ₃ are most preferred.

(F) As for the mass mean molecular weight (Mw) (polystyrene conversion reference | standard by a gel permeation chromatography), 1000-50000 are preferable, 5000-40000 are more preferable, and 10000-30000 are the most preferable. 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 (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

(F) A component may be used individually by 1 type and may use 2 or more types together.
(F) A component is used in the ratio of 0.5-10 mass parts with respect to 100 mass parts of (A) component.

[Amine; component (D)]
In the resist pattern forming method of the present invention, a nitrogen-containing organic compound component (D) (hereinafter referred to as “component (D)”) can be added to the resist composition.
Since the resist composition used in the pattern forming method of the present invention contains the component (G), the solubility of the component (A) in the alkaline developer is increased by the component (G) in the resist composition solution. There is a risk of it. The occurrence of this phenomenon can be suppressed by adjusting the acidity of the (G) component or the like to an appropriate level, but the (D) component is added and the (G) component in the resist composition liquid is added. It can also be suppressed by reducing the acidity. When the component (D) is used, the degree of freedom in selecting a material such as the component (G) is increased, which is preferable.
In addition, the storage stability after preparation of the resist composition solution is enhanced by the presence of the component (D) during storage of the resist composition. In addition, by removing the component (D) from the resist film before neutralization in the step (4), the base generated from the component (C) in the step (4) and the component (G) are neutralized ( Since component D) does not interfere, particularly good lithography properties and pattern shapes can be obtained, which is preferable.

Since a wide variety of components (D) have already been proposed, any known component may be used. Especially, as (D) component, that whose pKa is equal to or less than pKa of the cation of (G1) component mentioned above is preferable. That is, the pKa of the component (D) is preferably 7 or less, and more preferably 6 or less.
When the component (G1) is contained, the cation of the component (G1) and the component (D) should be equal to or less than the pKa of the component cation (G1) in order to prevent salt exchange. Is more preferable.
When the component (G2) is contained, the basicity of the component (D) is preferably low so that the acidity of the component (G2) is not extremely lowered, and the pKa is preferably 7 or less, and 6 or less. It is more preferable that

As the component (D) that satisfies the pKa, in the formula (G1c-1) exemplified in the description of the component (G1), an amine obtained by removing one “H ⁺ ” bonded to the nitrogen atom (N) is used. Can be mentioned. Specifically, in the specific examples given in the above formulas (G1c-11) and (G1c-13), a compound in which the terminal “NH ₃ ⁺ ” is “NH ₂ ”; the above formula (G1c-12) In the specific examples mentioned in the above, compounds in which “NH ⁺ ” in the ring is “N” are preferred.

In addition, the component (D) is preferably an amine having a relatively low boiling point. By using an amine having a relatively low boiling point, the component (D) can be easily removed from the resist film when the resist film is formed on the support in step (1).
The component (D) that satisfies the boiling point is preferably an amine having a boiling point of 130 ° C. or lower, more preferably an amine having a boiling point of 100 ° C. or lower, and particularly preferably an amine having a boiling point of 90 ° C. or lower.
As a specific example of the component (D) that satisfies the above pKa and boiling point,
Trifluoroethylamine (2,2,2-trifluoroethylamine), pentafluoropropylamine (2,2,3,3,3-pentafluoropropylamine), heptafluorobutylamine (1H, 1H-heptafluorobutylamine), nona Fluoropentylamine (1H, 1H-nonafluoropentylamine), undecafluorohexylamine (1H, 1H-undecafluorohexylamine),
Fluorine such as bis (2,2,2-trifluoroethyl) amine, bis (2,2,3,3,3-pentafluoropropyl) amine, 1- (2,2,2-trifluoroethyl) pyrrolidine An aliphatic amine compound having an alkyl group;
Examples thereof include pyridine compounds such as pyridine and pentafluoropyridine; oxazole compounds such as oxazole and isoxazole.

(D) A component may be used individually by 1 type and may be used in combination of 2 or more type.
When the resist composition of this invention contains (D) component, it is preferable that the ratio of (D) component is 0.01-20.0 mass parts with respect to 100 mass parts of (A) component, 1-15 mass parts is more preferable, and 2-10 mass parts is especially preferable. By setting it as the said range, storage stability can be improved and the lithography characteristic and resist pattern shape which are obtained also improve.

  The resist composition used in the present invention may further contain, if desired, miscible additives such as an additional resin for improving the performance of the resist film, a surfactant for improving coating properties, and a dissolution inhibitor. , Plasticizers, stabilizers, colorants, antihalation agents, dyes, sensitizers, base proliferating agents, and the like can be appropriately added and contained.

Specific examples of sensitizers include benzobenzophenone sensitizers such as benzophenone and p, p'-tetramethyldiaminobenzophenone; carbazole sensitizers, acetophene sensitizers, naphthalene sensitizers, and phenol sensitizers. Sensitizers, anthracene sensitizers such as 9-ethoxyanthracene, and known sensitizers such as biacetyl, eosin, rose bengal, pyrene, phenothiazine, and anthrone can be used. It is preferable that content of the sensitizer in a resist composition is 0.5-20 mass parts with respect to 100 mass parts of (A) component.
The base proliferating agent decomposes in a chain reaction by the action of a base and generates a large amount of base with a small amount of base. For this reason, the sensitivity of a resist composition can be improved by mix | blending a base growth agent. As the base proliferating agent, for example, those described in JP-A No. 2000-330270 and JP-A No. 2008-174515 can be used.

[Organic solvent: (S) component]
The resist composition used in the present invention can be produced by dissolving the material in an organic solvent (hereinafter also 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. 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; 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, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone, and 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 the component (S) used is not particularly limited and is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. Generally, the solid content concentration of the resist composition is It is used in a range of 1 to 20% by mass, preferably 2 to 15% by mass.

≪Protective film forming composition≫
The protective film forming composition used in the resist pattern forming method of the present invention can be any one that can reduce the environmental impact of the resist film when a protective film made of the protective film forming composition is provided on the resist film. Although not particularly limited, it is preferable to contain a resin (A ′) because of its excellent film forming ability.

<Resin (A ')>
Resin (A ') will not be specifically limited if a protective film can be formed, A well-known resin can be utilized. In particular, in step (5), since the protective film formed can be removed simultaneously with the resist pattern formation by alkali development, the alkali-soluble resin (A′1) (hereinafter referred to as “component (A′1)”). It is preferable to use.

Examples of the component (A′1) include resins having an alkali-soluble group. Conventionally known resins such as a novolak resin, a hydroxystyrene resin, an acrylic resin, and a polycycloolefin resin have an alkali-soluble group. Is mentioned.
The “novolak resin” is a resin obtained by, for example, addition condensation of an aromatic compound having a phenolic hydroxyl group and an aldehyde under an acid catalyst.
The “hydroxystyrene-based resin” is a resin containing the above-described “structural unit derived from hydroxystyrene or a hydroxystyrene derivative”.
The “acrylic resin” is a resin containing the “structural unit derived from an acrylate ester” described above.
The “polycycloolefin-based resin” is a resin containing a structural unit constituted by cleavage of a double bond of a polycycloolefin.
Especially, as a (A'1) component of the composition for protective film formation used in the resist pattern formation method of this invention, polycycloolefin type-resin (A'11) which has an alkali-soluble group is preferable, and following formula (a '1) structural units represented by (ie bicyclo [2.2.1] -2-heptene (norbornene) structural unit derived from, or tetracyclo ^[4.4.0.1 2.5 ^{.1. 7 .10} ] -3-dedecene is preferred.

［式中、ａ’は０又は１であり、Ｒ^６’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。ｚ’は０〜３の整数であり、Ｑ^ａは単結合又は２価の連結基であり、Ｘ^ａはアルカリ可溶性基である。］

[Wherein, a ′ is 0 or 1, and R ⁶ ′ 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. Z ′ is an integer of 0 to 3, Q ^a is a single bond or a divalent linking group, and X ^a is an alkali-soluble group.]

In formula (a′1), a ′ is 0 or 1, and is preferably 0 in consideration of industrial availability.
In the formula (a′1), z is an integer of 0 to 3, and 0 or 1 is preferable.
In formula (a′1), the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group of R ⁶ ′ are the same as R in the structural unit (a0). ^{This is the same as} the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group.

In formula (a′1), Q ^a is a single bond or a divalent linking group. Q As the divalent linking group represented by ^a, the same as the divalent linking group Y2 in the formula (a1-0-2), and the like, an aliphatic substituted hydrocarbons group, or preferably a divalent linking group containing a hetero atom, a linear or branched alkylene ^{group, -Y 21 -O-Y 22 -} , - [Y 21 -C (= O) -O] m _' -(Wherein Y ²¹ and Y ²² are the same as described above) is more preferable.

Wherein (a'1), ^{X a} is an alkali-soluble group. Specifically, phenolic hydroxyl group, carboxy group, fluorinated alcohol group, sulfonic acid group, sulfonamide group, fluorinated alkylsulfonamide group, sulfonylimide group, (alkylsulfonyl) (alkylcarbonyl) methylene group, (alkylsulfonyl) ) (Alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris ( Examples include alkylsulfonyl) methylene groups.
Among these, since the environmental influence of the resist film can be more effectively reduced when the structural unit (a′1) has a fluorine atom, the alkali-soluble group of X ^a is preferably a group containing a fluorine atom. More preferably, it is a fluorinated alcohol group or a fluorinated alkylsulfonamide group.

  As the structural unit (a′1), a structural unit having a fluorinated alkylsulfonamide structure represented by the following general formula (a′1-1) is particularly preferable.

［式中、ａ’、Ｙ^２１、Ｙ^２２、Ｒ^６’、ｚ’はそれぞれ前記同様であり、ｂ、ｃはそれぞれ独立に１〜５の整数である。］

[Wherein, a ′, Y ²¹ , Y ²² , R ⁶ ′, z ′ are the same as defined above, and b, c are each independently an integer of 1-5. ]

  In the formula (a′1-1), c is an integer of 1 to 5, preferably an integer of 1 to 3, and most preferably 1. b is an integer of 1-5, the integer of 1-3 is preferable and 1 is the most preferable.

As the structural unit (a′1), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a′1) in the component (A′1) is preferably 1 mol% or more, preferably 10 mol%, based on the total of all structural units constituting the component (A′1), 30 The mol% is more preferable, 50 mol% is more preferable, and 100 mol% (homopolymer) may be sufficient. When the proportion of the structural unit (a′1) is within the above range, desired alkali solubility is more easily obtained.

  The monomer for deriving the structural unit (a′1) can be synthesized, for example, by the technique disclosed in US Pat. No. 6,420,503.

  The component (A′1) is a structural unit derived from a polycycloolefin having a fluorinated alkyl group as a substituent in addition to the structural unit (a′1), and includes the structural unit (a′1). Not applicable structural unit (hereinafter, this structural unit is referred to as “structural unit (a′2)”), specifically, a structural unit represented by the following general formula (a′2-1) Good. By containing the structural unit (a′2), the environmental influence of the resist film can be more effectively reduced.

［式中、ａ’、Ｒ^６’、ｚ’はそれぞれ前記同様であり、Ｒ^２７はフッ素化アルキル基である。］

[Wherein, a ′, R ⁶ ′ and z ′ are the same as defined above, and R ²⁷ represents a fluorinated alkyl group. ]

In the formula (a′2-1), a is 0 or 1, and is preferably 0 in consideration of industrial availability.
In the formula (a′2-1), R ²⁷ is a fluorinated alkyl group, and a group in which part or all of the hydrogen atoms of a linear, branched or cyclic alkyl group are substituted with fluorine atoms. is there.
As a linear or branched alkyl group, a C1-C10 alkyl group is preferable, a C1-C8 alkyl group is more preferable, and a C1-C5 alkyl group is further more preferable. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a pentyl group, an isopentyl group, and a neopentyl group, and a propyl group is particularly preferable.
The cyclic alkyl group preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Among the above, as the fluorinated alkyl group for R ^27, a group in which one hydrogen atom of a linear or branched alkyl group is substituted with a perfluoroalkyl group (an alkylene group is added to the perfluoroalkyl group). A bonded group), and — (CH ₂ ) _f —CF ₃ , — (CH ₂ ) _f —C ₂ F ₅ [f = 1 to 3] are more preferable, —CH ₂ —CF ₃ , —CH ₂ -C ₂ F ₅ are particularly preferred.
As the fluorinated alkyl group, in particular, those having a fluorination rate (ratio of the number of fluorine atoms to the total number of hydrogen atoms and fluorine atoms (%) in the fluorinated alkyl group) of 30 to 90%. Preferably, 50 to 80% is more preferable. When the fluorination rate is 30% or more, the environmental influence of the resist film can be more effectively reduced. Moreover, it is excellent in the effect of improving the hydrophobicity of the protective film surface under immersion exposure conditions. Further, when the fluorination rate is 90% or less, the development characteristics are improved.

  When the structural unit (a′2) is contained in the component (A′1), the structural unit (a′2) is 5 to 5 times the total of all the structural units constituting the component (A′1). It is preferable to contain 75 mol%, more preferably 10 to 70 mol%, and still more preferably 15 to 60 mol%. By setting it as the said range, an environmental influence can be reduced especially suitably. Moreover, the hydrophobicity of the protective film surface improves by setting it as the said range.

  The monomer for deriving the structural unit represented by the formula (a′2-1) is, for example, a method disclosed in JP 2000-235263 A [fluorinated alkyl ester of (meth) acrylic acid and cyclohexane]. [Method of reacting pentadiene or dicyclopentadiene with Diels-Alder reaction, which is a known reaction].

As the component (A′1), one type may be used alone, or two or more types may be used in combination.
The mass average molecular weight (Mw) of the component (A′1) (polystyrene conversion standard by gel permeation chromatography (GPC)) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, 2000-20000 is most preferable. Within this range, there is sufficient solubility in an organic solvent to be used as a resin component for forming the protective film, the alkali development characteristics are good, and the film formability is also good.
Further, the dispersity (Mw / Mn) of the component (A′1) is not particularly limited, but is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and 1.0 to 2. 5 is most preferred.

The component (A′1) is obtained, for example, by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). Can do.
Moreover, when it has a main chain cyclic | annular structural unit, (A'1) component is compoundable by the method as described in Unexamined-Japanese-Patent No. 2006-291177, for example.

<Acid supply component; (Z ′) component>
The composition for forming a protective film may further contain an acid supply component (Z ′) (hereinafter referred to as “(Z ′) component”). When the composition for forming a protective film contains (Z ′), in the step (4), an increase in solubility of the unexposed portion resist film in an alkaline developer can be further promoted.
Specific examples of the component (Z ′) include an acidic compound component and an acid generator component, which are the same as the component (G) and the component (B), respectively.
As the component (Z ′), one type may be used alone, or two or more types may be used in combination.
When the composition for forming a protective film contains the (Z ′) component, the resin (A ′) and an organic solvent described later, the content of the (Z ′) component is 100 parts by mass of the resin (A ′). It is preferable that it is 0.1-60 mass parts. When the component (Z ′) is an acidic compound component, 0.1 to 50 parts by mass is more preferable, and 1 to 20 parts by mass is more preferable with respect to 100 parts by mass of the resin (A ′). When the component (Z ′) is an acid generator component, 1 to 60 parts by mass is more preferable, and 1 to 50 parts by mass is more preferable with respect to 100 parts by mass of the resin (A ′). When the content of the (Z ′) component is at least the lower limit value, a sufficient amount of acid is supplied to the resist film, so that the solubility in an alkali developer tends to increase in the unexposed area, and the resolution is further improved. improves. On the other hand, when the content of the (Z ′) component is not more than the upper limit value, the sensitivity is improved. Moreover, when each component is dissolved in an organic solvent, a uniform solution is obtained, and the storage stability is improved.

<Organic solvent; component (S ')>
The composition for forming a protective film can be used by dissolving in an organic solvent. As an organic solvent mix | blended with the composition for protective film formation, what can melt | dissolve each component to be used and can make a uniform solution should just be used. For example, any one or more of conventionally known solvents for chemically amplified resists can be appropriately selected and used. Examples of the organic solvent include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; ethylene glycol, diethylene glycol, propylene glycol, Polyhydric alcohols such as dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, the polyhydric alcohols or compounds having the ester bond Monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, etc. Derivatives of polyhydric alcohols such as compounds having an ether bond such as ruether [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane And esters such as methyl lactate, 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, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, An aromatic organic solvent such as mesitylene can be used.

As the organic solvent blended in the protective film forming composition, an alcohol organic solvent, a fluorine organic solvent, an ether organic solvent having no hydroxyl group, or the like can be used. Since these organic solvents are difficult to dissolve the resist film formed by the resist composition described above, they are preferably used as the organic solvent of the protective film forming composition.
Any one of the organic solvents listed below may be used alone, or two or more thereof may be mixed and used. Alcohol-based organic solvents are preferred from the viewpoint of applicability and solubility of materials such as resin components.

Here, the “alcohol-based organic solvent” is a compound in which at least one of the hydrogen atoms of the aliphatic hydrocarbon is substituted with a hydroxyl group, and is a compound that is liquid at normal temperature and normal pressure. The structure of the main chain constituting the aliphatic hydrocarbon may be a chain structure, may be a cyclic structure, may have a cyclic structure in the chain structure, The chain structure may contain an ether bond.
The “fluorine-based organic solvent” is a compound containing a fluorine atom and is a liquid at normal temperature and normal pressure.
The “ether-based organic solvent having no hydroxyl group” is a compound that has an ether bond (C—O—C) in its structure, does not have a hydroxyl group, and is liquid at normal temperature and pressure. The ether organic solvent having no hydroxyl group preferably further has no carbonyl group in addition to the hydroxyl group.

As the alcohol organic solvent, monohydric alcohols, dihydric alcohols, derivatives of dihydric alcohols, and the like are preferable.
As the monohydric alcohol, although depending on the number of carbon atoms, a primary or secondary monohydric alcohol is preferable, and a primary monohydric alcohol is most preferable.
Here, the monohydric alcohol means a compound in which one of the hydrogen atoms of a hydrocarbon compound composed only of carbon and hydrogen is substituted with a hydroxyl group, and does not include a dihydric or higher polyhydric alcohol derivative. The hydrocarbon compound may have a chain structure or a cyclic structure.
The dihydric alcohol means a compound in which two hydrogen atoms of the hydrocarbon compound are substituted with a hydroxyl group, and does not include a trihydric or higher polyhydric alcohol derivative.
Examples of the dihydric alcohol derivative include compounds in which one of the hydroxyl groups of the dihydric alcohol is substituted with a substituent (such as an alkoxy group or an alkoxyalkyloxy group).

The boiling point of the alcohol-based organic solvent is preferably 80 to 160 ° C., more preferably 90 to 150 ° C., and preferably 100 to 135 ° C., coating property, stability of composition during storage, and heating temperature. From the viewpoint of
Specific examples of such alcohol-based organic solvents include those having a chain structure such as propylene glycol (PG); 1-butoxy-2-propanol (BP), n-hexanol, 2-heptanol, 3-heptanol, and 1-heptanol. 5-methyl-1-hexanol, 6-methyl-2-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2-ethyl-1-hexanol, 2- (2-butoxyethoxy) ethanol N-pentyl alcohol, s-pentyl alcohol, t-pentyl alcohol, isopentyl alcohol, isobutanol (also referred to as isobutyl alcohol or 2-methyl-1-propanol), isopropyl alcohol, 2-ethylbutanol, neopentyl alcohol, n-bu Nord, s- butanol, t-butanol, 1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol.
In addition, as those having a cyclic structure, cyclopentanemethanol, 1-cyclopentylethanol, cyclohexanol, cyclohexanemethanol (CM), cyclohexaneethanol, 1,2,3,6-tetrahydrobenzyl alcohol, exo-norbornol, 2-methyl Examples include cyclohexanol, cycloheptanol, 3,5-dimethylcyclohexanol, and benzyl alcohol.

  Among alcohol-based organic solvents, chain-structured monohydric alcohols or dihydric alcohol derivatives are preferable, such as 1-butoxy-2-propanol (BP); isobutanol (2-methyl-1-propanol), 4-methyl. 2-Pentanol and n-butanol are more preferable, and isobutanol (2-methyl-1-propanol) and 1-butoxy-2-propanol (BP) are particularly preferable.

  Examples of the fluorine-based organic solvent include perfluoro-2-butyltetrahydrofuran.

Preferred examples of the ether organic solvent having no hydroxyl group include compounds represented by the following general formula (s-1).
R ⁴⁰ —O—R ⁴¹ (s-1) [wherein R ⁴⁰ and R ⁴¹ are each independently a monovalent hydrocarbon group, and R ⁴⁰ and R ⁴¹ combine to form a ring. It may be. -O- represents an ether bond. ]

In the above formula, examples of the hydrocarbon group for R ⁴⁰ and R ⁴¹ include an alkyl group and an aryl group, and an alkyl group is preferred. Among ^them, it is preferable that any of R ^{40, R 41} is an alkyl ^group, more preferably a ^{R 40} and ^{R 41} are the same alkyl group.
As each of the alkyl groups of R ^40, R ^41, not particularly limited, for example, straight, branched or cyclic alkyl group, and the like. In the alkyl group, part or all of the hydrogen atoms may or may not be substituted with a halogen atom or the like.
The alkyl group preferably has 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms because of good coating properties on the resist film. Specific examples include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, and a hexyl group, and an n-butyl group and an isopentyl group are particularly preferable. .
The halogen atom that may be substituted for the hydrogen atom of the alkyl group is preferably a fluorine atom.
Each aryl group for R ⁴⁰ and R ⁴¹ is not particularly limited, and is, for example, an aryl group having 6 to 12 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups, It may or may not be substituted with a halogen atom or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specifically, a phenyl group, a benzyl group, a naphthyl group, etc. are mentioned, for example.
The alkyl group that may be substituted for the hydrogen atom of the aryl group 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. Is more preferable.
As the alkoxy group which may substitute the hydrogen atom of the said aryl group, a C1-C5 alkoxy group is preferable and a methoxy group and an ethoxy group are more preferable.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
In the above formula, R ⁴⁰ and R ⁴¹ may combine to form a ring.
R ⁴⁰ and R ⁴¹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 10 carbon atoms), and the end of R ⁴⁰ is bonded to the end of R ^41. To form a ring. In addition, the carbon atom of the alkylene group may be substituted with an oxygen atom.
Specific examples of the ether organic solvent include 1,8-cineol, tetrahydrofuran, dioxane and the like.

The boiling point (under normal pressure) of the ether-based organic solvent having no hydroxyl group is preferably 30 to 300 ° C, more preferably 100 to 200 ° C, and further preferably 140 to 180 ° C. By being above the lower limit of the temperature range, during spin coating during coating, it becomes difficult to evaporate and coating unevenness is suppressed, and coating properties are improved. On the other hand, by being below the upper limit, the organic solvent is sufficiently removed from the protective film by baking, and the formability of the protective film is improved. Further, when the temperature is within this range, the stability of the composition during storage is further improved. Moreover, it is preferable also from a viewpoint of heating temperature.
Specific examples of ether organic solvents having no hydroxyl group include, for example, 1,8-cineol (boiling point 176 ° C.), dibutyl ether (boiling point 142 ° C.), diisopentyl ether (boiling point 171 ° C.), dioxane (boiling point 101 ° C.). ), Anisole (boiling point 155 ° C.), ethyl benzyl ether (boiling point 189 ° C.), diphenyl ether (boiling point 259 ° C.), dibenzyl ether (boiling point 297 ° C.), phenetole (boiling point 170 ° C.), butyl phenyl ether, tetrahydrofuran (boiling point 66 ° C.) ), Ethyl propyl ether (boiling point 63 ° C.), diisopropyl ether (boiling point 69 ° C.), dihexyl ether (boiling point 226 ° C.), dipropyl ether (boiling point 91 ° C.) and the like.
The ether organic solvent having no hydroxyl group is preferably a cyclic or chain ether organic solvent, and at least one selected from the group consisting of 1,8-cineol, dibutyl ether and diisopentyl ether. Species are preferred.

  The amount of the organic solvent used in the composition for forming a protective film is not particularly limited, and may be appropriately set according to the coating film thickness at a concentration that can be applied on the resist film. For example, when a protective film forming composition containing a component (Z ′), a resin (A ′), and a component (S ′) is used, the content of the organic solvent is such that the resin (A ′) concentration is 0. The amount is preferably 2 to 10% by mass, and more preferably 1 to 5% by mass.

If desired, the composition for forming a protective film may further contain a surfactant, a sensitizer, a crosslinking agent, an antihalation agent, a storage stabilizer, a colorant, a plasticizer, an antifoaming agent, and the like as desired. it can.
Surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, polyalkylene oxide surfactants, fluorine-containing surfactants, etc. Can be mentioned. When using a surfactant, the content is preferably 0.01 to 0.5 parts by mass, more preferably 0.02 to 0.1 parts by mass with respect to 100 parts by mass of the resin.

[Reference Examples 1-2, Examples 1-2, Comparative Examples 1-2]
A resist composition was prepared by mixing and dissolving the components shown in Table 1.

In Table 1, the numerical value in [] is a blending amount (part by mass), and each abbreviation has the following meaning.
(A) -1: Copolymer represented by the following chemical formula (A) -1 [Mw = 7000, Mw / Mn = 1.57. l / m / n = 40/40/20 (copolymerization composition ratio (molar ratio)). ]
(A) -2: Copolymer represented by the following chemical formula (A) -2 [Mw = 7000, Mw / Mn = 1.57. l / m / n = 45/35/20 (copolymerization composition ratio (molar ratio)). ]
(C) -1: a compound represented by the following chemical formula (C) -1.
(G1) -1: a compound represented by the following chemical formula (G1) -1 [cation pKa = 5.7, anion pKa = -11.55].
(G2) -1: a compound represented by the following chemical formula (G2) -1 [pKa = -11.55].
(D) -1: a compound represented by the following chemical formula (D) -1 [pKa = 5.6].
(F) -1: Compound represented by the following chemical formula (F) -1 [Mw = 25000, Mw / Mn = 1.9. l = 100 (molar ratio). ]
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

[Formation of resist pattern]
(Process (1))
An organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thus, an organic antireflection film having a film thickness of 82 nm was formed.
Next, each of the resist compositions of each example was applied using a spinner, and for Reference Example 2, Example 2 and Comparative Example 2, a pre-bake (PAB) treatment was performed at 80 degrees for 60 seconds. In Example 1 and Comparative Example 1, a resist film having a film thickness of 100 nm was formed by allowing to stand for 60 seconds on a cooling plate at 23 ° C. and drying each.
(Process (2))
Next, the protective film forming material was applied onto the resist films of Examples 1 and 2 using a spinner. After coating, Example 2 was baked at 80 ° C. for 60 seconds, and Example 1 was kept at 23 ° C. on a cooling plate for 60 seconds and dried to protect the film thickness of 35 nm. A film was formed. In Reference Examples 1 and 2 and Comparative Examples 1 and 2, the step (2) is not performed and the protective film is not formed.
The composition for forming a protective film comprises 100 parts by mass of a homopolymer represented by the above formula (A ′)-1 (Mw = 5300), 0.3 parts by mass of the compound represented by the above formula (G2) -1, and It is prepared by mixing and dissolving 5000 parts by mass of isobutanol.

(Process delay)
In Examples 1-2 after the completion of the step (2) and Comparative Examples 1-2 after the completion of the step (1), the resist film was allowed to stand in a clean room for 15 minutes to delay the process. In Reference Examples 1 and 2, no process delay is performed.

(Process (3))
Next, with respect to the resist film, Reference Example 1, Example 1 and Comparative Example 1 had a space width of ArF exposure apparatus NSR-S302 (manufactured by Nikon Corporation; NA (numerical aperture) = 0.60, 2/3 Annular). Masks targeting a 1: 3SL pattern with 200 nm and a pitch of 800 nm, Reference Example 2, Example 2 and Comparative Example 2 are respectively passed through masks targeting a space width of 150 nm and a pitch of 375 nm with a target of 1: 1.5SL. IrF excimer laser (193 nm) was irradiated.
(Process (4))
Next, a post-exposure heating (PEB) treatment was performed for 60 seconds at the temperatures shown in Table 2.
(Process (5))
Next, alkali development was performed at 23 ° C. with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 30 seconds.
As a result, in Reference Examples 1-2 and Examples 1-2, the target SL pattern was formed on the resist film. The optimum exposure dose Eop at this time, Reference Example 1 and Example 1 10.5mJ / cm ^2, Reference Example 2 and Example 2 was 41 mJ / cm ^2. In Comparative Examples 1 and 2, no pattern was obtained. The results and evaluation conditions are summarized in Table 2.

  From the above results, in the methods of Examples 1 and 2 for forming the protective film, even when a process delay occurs, a pattern can be formed in the same manner as when there is no process delay (Reference Examples 1 and 2). It could be confirmed. On the other hand, it was also confirmed that a pattern could not be formed in Comparative Examples 1 and 2 in which the protective film was not formed and the process delay occurred.

Claims (1)

A resist composition containing a base component whose solubility in an alkali developer is increased by the action of an acid, a photobase generator component that generates a base upon exposure, and an acidic compound component is applied onto a support. Forming a resist film (1);
(2) forming a protective film by applying a protective film-forming composition on the resist film;
Exposing the resist film and the protective film (3);
Baking is performed after the step (3), and in the exposed portion of the resist film, the base generated from the photobase generator component by the exposure is neutralized with the acidic compound component, and the resist film is unexposed. The step (4) of increasing the solubility of the base component in an alkaline developer by the action of the acidic compound component;
And (5) forming a negative resist pattern in which the resist film is alkali-developed and an unexposed portion of the resist film is dissolved and removed.

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