JP6126807B2 - Pattern formation method - Google Patents

Description

  The present invention relates to a method for forming a pattern using a phase separation structure of a block copolymer.

In recent years, with the further miniaturization of large-scale integrated circuits (LSIs), a technique for processing more delicate structures is required. In response to such a demand, a method of forming a finer pattern using a phase separation structure formed by self-assembly of a block copolymer in which mutually incompatible blocks are bonded to each other is disclosed. (For example, refer to Patent Document 1).
In order to utilize the phase separation of the block copolymer, it is essential to form the self-assembled nanostructure formed by the microphase separation only in a specific region and arrange it in a desired direction. In order to realize these position control and orientation control, there are proposed methods such as graphoepitaxy for controlling the phase separation pattern by the guide pattern and chemical epitaxy for controlling the phase separation pattern by the difference in the chemical state of the substrate. (For example, refer nonpatent literature 1.).

In order to realize the position control and the orientation control, a resist material containing a base material component such as a resin is used for forming the guide pattern. 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. .
It has been proposed to use a negative development process when forming a guide pattern used to form a fine pattern utilizing self-assembly of a block copolymer. The negative development process is a process (hereinafter referred to as organic development) in which the positive chemically amplified resist composition is combined with a developer containing an organic solvent (hereinafter also referred to as “organic developer”). The process using the liquid is sometimes referred to as “solvent development process” or “solvent development negative process”. In general, the positive chemically amplified resist composition increases the solubility in an alkali developer by exposure, but at this time, the solubility in an organic solvent relatively decreases. Therefore, in the solvent development negative type process, the unexposed portion of the resist film is dissolved and removed by the organic developer to form a resist pattern (see, for example, Patent Document 2).

JP 2008-36491 A JP 2009-025723 A

Proceedings of SPIE, Volume 7637, 76370G-1 (2010).

In the case of using a guide pattern formed using a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid, a block copolymer-containing composition The heat treatment at the time of phase separation may cause the sagging of the guide pattern, which may deform the shape of the guide pattern. In order to prevent thermal sag, it is required to perform the phase separation at as low a heating temperature as possible, but there is a problem that the phase separation efficiency is lowered when the heat treatment is performed at a low temperature. For this reason, conventionally, a neutralization film has been provided in advance on the bottom surface of the concave portion constituting the guide pattern so as to promote phase separation even at a low temperature.
However, since the step of forming the neutralization film leads to an increase in manufacturing cost, the neutralization film is not provided even though the guide pattern composed of the structural unit (a1) resist is used. There is a need for a method of separation.

  The present invention has been made in view of the above circumstances, and is formed of a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid. It is an object of the present invention to provide a pattern forming method capable of phase-separating a block copolymer-containing composition without providing a neutralized film at the bottom of the guide pattern, even though the guide pattern is used.

The first aspect of the present invention has a guide pattern formed on a surface of a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid. And for a support having no neutralization film on the bottom surface of the concave portion of the guide pattern,
A block copolymer layer forming step of forming a block copolymer-containing layer using a composition comprising a block copolymer in which a plurality of types of blocks are bonded and an organic solvent so as to cover the bottom surface of the concave portion of the guide pattern;
After the block copolymer layer forming step, a phase separation step for phase separation of the layer containing the block copolymer;
After the phase separation step, a step of selectively removing a phase composed of at least one block of a plurality of types of blocks constituting the block copolymer from the layer containing the block copolymer,
The guide pattern of the bottom and side surfaces constituting the concave portion of the state, and are the absolute value of 5 degrees or more of the difference between the water contact angle,
Said composition comprising the block copolymer and the organic solvent, further, the vapor pressure at 20 ° C. is not more than 0.05HPa, a pattern forming method and the freezing point is characterized that you containing compound is 25 ° C. or less It is.
In the pattern forming method, the block copolymer layer is preferably subjected to phase separation by performing heat treatment at 100 to 180 ° C. for 10 to 600 seconds in the phase separation step .

In the present specification and claims, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “alkylene group” includes linear, branched, and cyclic divalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
“Fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which part or all of the hydrogen atoms of an alkyl group or alkylene group are substituted with fluorine atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
“A 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”.
“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.
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.
“Styrene” is a concept that includes styrene and those in which the α-position hydrogen atom of styrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group.
“Structural unit derived from styrene” and “structural unit derived from styrene derivative” mean a structural unit formed by cleavage of an ethylenic double bond of styrene or a styrene derivative.
The alkyl group as the 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, an n-butyl group, an isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.
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.
“Exposure” is a concept including general irradiation of radiation.

  According to the pattern forming method of the present invention, a guide pattern formed by a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid is used. Nevertheless, it is possible to provide a pattern forming method capable of phase-separating the block copolymer-containing composition without providing a neutralized film at the bottom of the guide pattern. As a result, the pattern forming process can be simplified and the manufacturing cost can be reduced.

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

Hereinafter, although this invention is demonstrated concretely, this invention is not limited to this.
<Pattern formation method>
The pattern forming method of the present invention has a guide pattern formed on a surface by a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid. Use a support. At this time, it is not necessary to provide a neutralization film described later on the bottom surface of the concave portion of the guide pattern.

  In the pattern forming method of the present invention, a support is used in which the absolute value of the difference between the “water contact angle” between the side surface (side wall) and the bottom surface constituting the recess of the guide pattern is 5 degrees or more. When the absolute value of the difference in “water contact angle” is ± 5 degrees or more, the block copolymer-containing composition placed in the recess can be sufficiently phase-separated by heat treatment at a relatively low temperature.

  One reason for this mechanism is that the properties of the side surface and the bottom surface that constitute the recess, that is, the physicochemical properties relating to the “water contact angle” are different, and thus the recess of the plurality of types of blocks constituting the block copolymer. A block having affinity for the side surface of the recess is attracted to the side surface, or a block having non-affinity on the side surface of the concave portion is separated (alienated) from the side surface, thereby promoting phase separation and relatively low temperature. Even so, it is conceivable that phase separation proceeds sufficiently.

  Hereinafter, the “water contact angle” may be simply referred to as “water contact angle”. In the present invention, the water contact angle employs a measured value using a known method θ / 2 method and JIS R 325 (1999). The water contact angle can be measured by, for example, Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.).

The water contact angle of the bottom surface of the concave portion of the guide pattern is obtained by measuring the water contact angle of the region corresponding to the bottom surface after the guide pattern is formed using a support body before the guide pattern is formed.
The water contact angle of the side surface of the concave portion of the guide pattern is not a method of measuring the water contact angle by dripping water on the side surface, but separately preparing a plane in the same state as the side surface and dripping water on the plane. The water contact angle measured in this way can be determined by regarding it as the water contact angle of the side surface of the recess. For example, when the guide pattern is formed by post-apply bake (PAB), exposure through a mask and post-exposure bake (PEB) after the resist film is formed, the same resist film is formed separately. By performing PAB treatment, full-surface exposure without using a mask, and PEB treatment under the same conditions, a flat surface that is substantially the same as the side surface of the concave portion of the guide pattern is formed on the upper surface (flat surface) of the resist film formed separately. Can be formed. It can be considered that the water contact angle of this plane is the same as the water contact angle of the side surface of the concave portion of the guide pattern. More specifically, the following method can be illustrated. The photosensitive resin composition was spin coated with Act-8, subjected to PAB treatment at 100 ° C. for 60 seconds, exposed to exposure at 30 mJ / cm ² without using a mask by Nikon S302, and then subjected to PEB treatment at 100 ° C. for 60 seconds. The contact angle of the surface of the resist film from which the protective group is deprotected is measured. This measured value can be regarded as the contact angle of the resist constituting the side surface (side wall portion) of the guide pattern formed under the same conditions.

  In the present invention, the absolute value of the difference in water contact angle may be 5 degrees or more, preferably 10 degrees or more, more preferably 15 degrees or more, and most preferably 20 degrees or more. preferable. The larger the absolute value of the difference, the more the phase separation of the block copolymer-containing composition can be promoted. The upper limit of the absolute value of the difference is not particularly limited, and may be 90 degrees or less, for example.

In the present invention, the water contact angle (θ _A ) on the side surface of the concave portion of the guide pattern is preferably larger on the positive side than the water contact angle (θ _B ) on the bottom surface of the concave portion. Due to this relationship of θ _A > θ _B , each phase of the block copolymer-containing composition phase-separated in the concave portion has a phase separation structure (see FIG. 1) laminated in parallel to the side surface of the concave portion. Easy to do.
The phase separation structure shown in FIG. 1 forms a striped pattern in which the separated phases extend in a substantially vertical direction with respect to the bottom surface of the concave portion when observed in a cross section in the thickness direction of the support having the concave portion. .

Therefore, the difference (θ _A −θ _B ) between θ _A and θ _B may be +5 degrees or more, preferably +10 degrees or more, more preferably +15 degrees or more, and +20 degrees or more. Most preferably. The differences are all positive values. The larger the difference, the more the phase separation of the block copolymer-containing composition can be promoted. The upper limit of the difference in water contact angle is not particularly limited, and may be, for example, 50 degrees or less.

  The pattern forming method of the present invention can be carried out using the support by at least the following three steps: a block copolymer layer forming step, a phase separation step, and a step of selectively removing a specific phase. it can. Details of each step will be described below.

<Block copolymer layer forming step (step 1)>
Hereinafter, the block copolymer layer forming step may be referred to as “step 1”. Step 1 includes the above-mentioned support having on its surface a guide pattern formed by a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid. On the other hand, it is a step of forming a layer containing a block copolymer using a composition containing a block copolymer so as to cover the bottom surface of the concave portion of the guide pattern.

[Support]
The material of the support can be appropriately selected from materials having a water contact angle different from the water contact angle of the side surface of the recess formed by the guide pattern.
The material of the support is not particularly limited as long as it does not dissolve when the block copolymer is applied, and a conventionally known material can be used as a substrate for an electronic component. For example, a silicon substrate, a metal substrate made of metal such as gold, copper, chromium, iron, and aluminum; a metal oxide substrate formed by oxidizing the metal; a glass substrate, a polymer film (polyethylene, polyethylene terephthalate, polyimide, benzocyclobutene) Etc.). Further, the size and shape of these substrates are not particularly limited. The substrate does not necessarily have a smooth surface, and substrates of various materials and shapes can be appropriately selected. For example, a substrate having a curved surface, a flat plate having an uneven surface, and a substrate having various shapes such as a thin piece can be used.

  In the pattern forming method of the present invention, the substrate described above may be used as it is as the support, or a substrate whose surface is processed as shown in FIG. For example, a substrate 11 in which an inorganic or organic film 12 is formed on the surface of the substrate 11 can be used.

The surface of the substrate 11 may be cleaned in advance. By cleaning the substrate surface, the water contact angle over the entire substrate surface can be made uniform. In addition, the cleaning treatment may improve the adhesion of the inorganic or organic film to the substrate surface.
As the cleaning treatment, conventionally known methods can be applied, and examples thereof include oxygen plasma treatment, ozone oxidation treatment, acid-alkali treatment, and chemical modification treatment.
Depending on the type and method of the cleaning treatment, the water contact angle on the surface may change. When the surface constitutes the bottom surface of the recess, it is desirable to consider the change in the water contact angle of the substrate surface before and after the cleaning process.

Examples of the inorganic film include an inorganic antireflection film (inorganic BARC). Examples of the organic film include an organic antireflection film (organic BARC).
The inorganic film can be formed by a known method. For example, the inorganic film can be formed by applying an inorganic antireflection film composition such as a silicon-based material on a substrate and baking it.
The organic film can be formed by a known method. For example, an organic film forming material in which a resin component or the like constituting the film is dissolved in an organic solvent is applied on a substrate with a spinner or the like. It can be formed by baking at a heating condition of ˜300 ° C., preferably 30 to 300 seconds, more preferably 60 to 180 seconds. The organic film forming material does not necessarily require sensitivity (photosensitivity) to light or an electron beam, and may or may not have such sensitivity. Specifically, resists and resins generally used in the manufacture of semiconductor elements and liquid crystal display elements can be used.

  It is also possible to transfer the pattern to the organic film by etching the organic film using a pattern made of a block copolymer formed on the organic film. As an organic film material suitable for this application, a material capable of forming an organic film capable of etching such as oxygen plasma etching is preferable. Specifically, materials for forming an organic film such as a conventional organic BARC can be applied. For example, ARC series manufactured by Brewer Science, AR series manufactured by Rohm and Haas, SWK series etc. are mentioned.

  In the pattern forming method of the present invention, it is not necessary to form a neutralized film on the substrate as the support. By omitting the neutralization film forming step and simplifying it, various costs (time, material, etc.) for the pattern forming method of the present invention can be reduced. However, in the present invention, a substrate provided with a neutralization film may be used as the support. When the neutralization film forms the bottom surface of the recess, the absolute value of the difference in water contact angle between the bottom surface and the side surface does not need to satisfy the above-described range.

The method for forming the neutralized film is not particularly limited, and can be formed by a conventionally known method. For example, by forming a coating film on a substrate by a conventionally known method such as applying a base material containing a material for a neutralized film on the substrate by a spin coating method using a spinner, and drying the coating, A neutral film can be formed. Details of the base agent will be described later.
As a method for drying the coating film, it is sufficient if the organic solvent contained in the base material can be volatilized, and examples thereof include a baking method.
The baking temperature is preferably 80 to 300 ° C, more preferably 100 to 270 ° C, and further preferably 120 to 250 ° C. The baking time is preferably 30 to 500 seconds, and more preferably 60 to 240 seconds.

Generally, by providing a neutralized film on the substrate surface, the surface of the substrate (the bottom surface of the concave portion) is neutralized, and only a phase composed of a specific block among the layers composed of block copolymers provided on the upper layer is the substrate. The contact with the surface can be suppressed. That is, the neutralized membrane does not act to positively promote phase separation of the layer containing the block copolymer, and is considered to provide a neutral surface with respect to phase separation. As a result, the layer containing the block copolymer spontaneously or phase-separated by interaction with the side surface of the recess, so that a cylinder structure, a dot structure, a gyroid structure, etc. that are freely oriented with respect to the substrate surface can be obtained. It becomes possible to form.
On the other hand, in the present invention, the phase separation is caused or promoted by making the absolute value of the difference in water contact angle between the side surface and the bottom surface of the recess larger than a predetermined value. It is not necessary to provide the neutralization film on the bottom surface.

[Base material (neutralized film composition)]
As a base agent (neutralized film composition) used for forming a neutralized film, any one of a plurality of types of blocks constituting the block copolymer to be put into the concave portion of the guide pattern may be used. It does not specifically limit, For example, a resin composition can be used.
The resin composition used as a base agent can be appropriately selected from conventionally known resin compositions used for forming a thin film, depending on the type of block constituting the block copolymer. The resin composition used as the base agent may be a thermopolymerizable resin composition or a photosensitive resin composition. Moreover, the composition which can form patterns, such as a positive resist composition and a negative resist composition, may be sufficient.
In addition, the layer 12 made of the base material may be a non-polymerizable film. For example, siloxane-based organic monomolecular films such as phenethyltrichlorosilane, octadecyltrichlorosilane, and hexamethyldisilazane can also be suitably used as the neutralized film.

Examples of such a base agent include, for example, a composition containing a resin including all the structural units of each block constituting the block copolymer, and all of a plurality of structural units having high affinity with each block constituting the block copolymer. Examples thereof include a composition containing a containing resin.
For example, when a PS-PMMA block copolymer is used, a resin containing both a structural unit derived from styrene and a structural unit derived from methyl methacrylate as a resin contained in the base agent; PS such as an aromatic ring It is preferable to use a resin or the like that includes both a part having high affinity and a part having high affinity to PMMA such as a functional group having high polarity.

Examples of the resin including both a structural unit derived from styrene and a structural unit derived from methyl methacrylate include a random copolymer obtained by random polymerization of styrene and methyl methacrylate.
As a resin including both a part having high affinity with PS and a part having high affinity with PMMA, for example, as a monomer, it is obtained by polymerizing at least a monomer having an aromatic ring and a monomer having a polar substituent. Resin.
As a monomer having an aromatic ring, 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 monomers having a heteroaryl group in which some of the carbon atoms constituting the ring of these groups are substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom.
In addition, examples of the monomer having a highly polar substituent include hydroxyalkyl in which a part of hydrogen atoms of a trimethoxysilyl group, a trichlorosilyl group, a carboxy group, a hydroxyl group, a cyano group, an amino group, and an alkyl group are substituted with a fluorine atom. And monomers having a group or the like.
In addition, as a compound containing both a site having high affinity with PS and a site having high affinity with PMMA, a compound containing both an aryl group such as phenethyltrichlorosilane and a highly polar substituent, an alkylsilane compound, etc. Examples include compounds containing both an alkyl group and a highly polar substituent.
These base agents (neutralized film compositions) differ in function and composition from the antireflection film compositions described above.

  Conventionally, a neutralization film for phase separation of a block copolymer has been provided separately from an antireflection film for forming a resist pattern. However, it is not necessary to provide a neutralization film in the present invention.

[Guide pattern formation; Graphoepitaxy]
In the present invention, it is preferable to provide the inorganic antireflection film or the organic antireflection film 12 on the substrate 11 as shown in FIG. By providing the antireflection film, the processing accuracy of the resist guide pattern can be improved, and the processing accuracy of the final target pattern can be improved as well.
It is preferable to form a guide pattern 14 made of a resist (hereinafter sometimes referred to as a resist pattern 14) on the surface of the antireflection film 12 formed on the substrate 11. Thereby, after forming the layer 13 containing a block copolymer, it becomes possible to control the arrangement structure of the phase separation structure in accordance with the shape or surface characteristics of the resist pattern 14. Such a resist pattern 14 functions as a guide pattern.

Specifically, first, a resist composition is applied onto a support with a spinner or the like, and a baking (post-apply bake (PAB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably A resist film is formed by applying for 60 to 90 seconds.
The resist composition is not particularly limited as long as it is a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases its polarity by the action of an acid. The composition is widely applicable, and either a resist composition suitable for an alkali development positive type process or a resist composition suitable for a solvent development negative type process can be used.
Here, the alkali development positive type process is a combination of the resist and the alkali developer by utilizing the property that the resist composition having the structural unit (a1) has increased solubility in an alkali developer upon exposure. A process. The solvent development negative type process is a combination of the resist and the developer containing the organic solvent by utilizing the property that the resist composition having the structural unit (a1) is less soluble in the organic solvent by exposure. Process.
The components of the resist composition suitable for the pattern forming method of the present invention will be described in detail later.

In the pattern forming method of the present invention, it is preferable to form a guide pattern by an alkali development positive type process for at least three reasons.
The first reason is that the alkali development positive type process has an advantage that the high-level waste liquid treatment required when the solvent development negative type process is used is unnecessary.
The second reason is that in the alkali development positive type process, the photomask structure can be simplified compared to the solvent development negative type process, and it is easy to obtain sufficient contrast for image formation. There are advantages such as superiority, and the guide pattern itself is superior to negative guide patterns in pattern characteristics (LWR, LER, CDU, defects), so the final pattern characteristics follow the guide pattern and are superior The effect of becoming.
The third reason is that in the alkali development positive type process, an alkali development apparatus that can be used for the existing positive type process can be continuously used.

  Next, the resist film is exposed through a mask (mask pattern) on which a predetermined pattern is formed using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, or a mask pattern. After performing selective exposure by drawing or the like by direct irradiation with an electron beam without passing through, baking (post-exposure baking (PEB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 Apply for ~ 90 seconds.

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF 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.

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure (Liquid Immersion Lithography).
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. It is an exposure method.
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 to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
As a solvent having a refractive index larger than that of air and smaller than that of the resist film, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility and the like.

Next, the resist film is developed. As the developer used for development, either an alkali developer or an organic solvent can be used.
A rinse treatment is preferably performed after the development treatment. By rinsing, a good pattern can be formed.
The rinse treatment after using the alkali developer is preferably a water rinse using pure water.
In the rinsing process after using the organic solvent, it is preferable to use a rinsing liquid containing an organic solvent that hardly dissolves the guide pattern.
Drying is performed after development or rinsing. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a guide pattern can be obtained.

[Developer]
Examples of the alkali developer used for the development treatment in the alkali development process include 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.

  The organic solvent used in the development process in the solvent development process is not particularly limited as long as it can dissolve the resin component (base material component) constituting the resist composition before exposure, and can be appropriately selected from known organic solvents. Specific examples include ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, nitrile solvents, and other polar solvents, hydrocarbon solvents, and the like. A solvent or a nitrile solvent is preferred.

  The ketone solvent is an organic solvent containing C—C (═O) —C in the structure. The ester solvent is an organic solvent containing C—C (═O) —O—C in the structure. The alcohol solvent is an organic solvent containing an alcoholic hydroxyl group in the structure, and “alcoholic hydroxyl group” means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. The amide solvent is an organic solvent containing an amide group in the structure. The ether solvent is an organic solvent containing C—O—C in the structure. Among organic solvents, there are organic solvents that contain multiple types of functional groups that characterize each of the above solvents in the structure, but in that case, any of the solvent types that contain the functional groups of the organic solvent is applicable. Shall. For example, diethylene glycol monomethyl ether corresponds to both alcohol solvents and ether solvents in the above classification. Further, the hydrocarbon solvent is a hydrocarbon solvent made of hydrocarbon and having no substituent (a group or atom other than a hydrogen atom and a hydrocarbon group).

  Specific examples of each solvent include ketone solvents such as 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, Methylcyclohexanone, phenylacetone, methylethylketone, methylisobutylketone, acetylacetone, acetonylacetone, ionone, diacetylalcohol, acetylcarbinol, acetophenone, methylnaphthylketone, isophorone, propylene carbonate, γ-butyrolactone, methylamylketone (2- Heptanone) and the like.

Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxy acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Propyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene group Coal monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, Propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxype Tyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, pyruvic acid Methyl, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, 2-hydroxypropionic acid Examples include ethyl, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate.
As the ester solvent, alkyl acetate is preferably used, and butyl acetate is more preferably used.

  Examples of the nitrile solvent include acetonitrile, propionitryl, valeronitrile, butyronitryl and the like.

  A known additive can be blended in the organic developer as required. Examples of the additive include a surfactant. The surfactant is not particularly limited. For example, ionic or nonionic fluorine-based and / or silicon-based surfactants can be used.

[Development method]
The development process can be performed by a known development method. Specifically, for example, a method in which a support is immersed in a developer for a certain period of time (dip method), a method in which a developer is raised on the surface of the support by surface tension and is allowed to stand for a certain period of time (paddle method), Examples include a method of spraying the developer (spray method), a method of continuously applying the developer while scanning the developer application nozzle at a constant speed on a support rotating at a constant speed (dynamic dispensing method), and the like. .

[Rinse processing]
After the development treatment, it is preferable to perform a rinsing treatment before drying. A good pattern can be formed by rinsing.
The rinse treatment after the alkali development process is preferably a water rinse using pure water.
The rinsing treatment after the solvent development process is preferably rinsing using a rinsing liquid containing an organic solvent that hardly dissolves the guide pattern. Moreover, you may use the following organic solvents as a rinse liquid.

  As the organic solvent used as the rinsing liquid, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents can be used. Among these, at least one selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents and amide solvents is preferable, and at least one selected from alcohol solvents and ester solvents is preferable. More preferred are alcohol solvents.

  The alcohol solvent used for the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched or cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. It is done. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferable, and 1-hexanol or 2-hexanol is more preferable.

  Any one of organic solvents used as the rinsing liquid may be used alone, or two or more organic solvents may be mixed and used. Moreover, you may mix and use the organic solvent and water other than the above. However, in consideration of development characteristics, the blending amount of water in the rinsing liquid is preferably 30% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, more preferably 3% by mass or less based on the total amount of the rinsing liquid. Is particularly preferred.

  A known additive can be blended in the organic developer as required. Examples of the additive include a surfactant. Examples of the surfactant include those described above, and nonionic surfactants are preferable, and fluorine-based surfactants or silicon-based surfactants are more preferable. When the surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0.5% by mass with respect to the total amount of the rinse liquid. % Is more preferable.

[Rinsing method]
The rinse treatment can be performed by a known rinse method. Specifically, for example, a method of continuously applying a rinsing liquid on a support rotating at a constant speed (rotary coating method), a method of immersing the support in the rinsing liquid for a certain time (dip method), and a support The method (spray method) etc. which spray a rinse liquid on the surface is mentioned.

[Dry]
Drying is performed after development or rinsing. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a guide pattern can be obtained.

[Exposure of resist residue]
In this invention, after forming a guide pattern using an alkali development positive resist composition or a solvent development negative resist composition, the resist residual part may be exposed and PEB may be performed. Here, the “resist remaining portion” means a resist film remaining on the substrate after development and pattern formation, for example, a line portion in a line and space pattern. By exposing the remaining resist portion, the resist composition is deprotected and the solubility in the organic solvent that dissolves the block copolymer described above is lowered. Thereby, the damage of the resist residual part by the organic solvent which becomes a problem when apply | coating a block copolymer to a guide pattern can be suppressed further.
The exposure is the same as described above, but it is sufficient that it is performed at least on the remaining resist portion, may be performed only on the remaining resist portion using a mask, or the entire surface may be exposed.

By exposing the resist remaining portion, the water contact angle (θ _A ) on the side surface of the concave portion of the guide pattern can be sufficiently reduced. However, when the water contact angle (θ _B ) on the bottom surface of the concave portion is θ _A > θ _B , the difference of θ _A −θ _B is reduced by exposure to the resist residual portion. In the present invention, it is preferable that the absolute value of the difference of θ _A −θ _B is large. Therefore, when θ _A > θ _B , it is preferable not to expose the resist residual portion.

  The pattern shape of the guide pattern formed on the surface of the substrate is not particularly limited, and may be appropriately designed based on a known method. Usually, it is preferable to form so as to surround a region where a final target pattern is to be formed and to mask a region other than the region. For example, when the region surrounded by the guide pattern on the substrate is a rectangle, or when the guide pattern forms a line and space pattern (LS pattern), a side of the rectangle or a striped shape along the LS pattern A final pattern can be formed. As another example, when the region surrounded by the guide pattern on the substrate is substantially circular, that is, when the guide pattern is a hole pattern, a substantially circular final pattern obtained by reducing the hole pattern can be formed. . The shape of the final pattern obtained by the pattern forming method of the present invention can be made a desired shape by appropriately designing the shape of the guide pattern.

  When a circular or elliptical hole pattern (guide hole) is used as the shape of the guide pattern in the present invention, the diameter or minor axis is preferably 30 nm to 400 nm. In this case, a pattern in which the size of the guide hole is reduced to about 0.1 to 0.5 times can be obtained as the final target pattern.

  When an LS pattern is used as the shape of the guide pattern in the present invention, the line width is preferably 30 nm to 400 nm. In this case, a pattern in which the size of the line width is reduced to about 0.1 to 0.5 times can be obtained as the final target pattern. The pitch width of the LS pattern can be set independently of the line width. For example, by setting the pitch width to 30 nm to 400 nm, a guide pattern that is an LS pattern having a pitch width and a line width of 1: 1 is used. be able to.

  When performing the pattern forming method of the present invention, when the guide pattern forms a side wall and the above-described block copolymer-containing composition of the present invention is applied, injected, or filled into a region surrounded by the side wall, the side wall of the guide pattern is It is preferable to be perpendicular or substantially perpendicular to the substrate.

[Guide film thickness]
The height of the guide pattern from the substrate surface (or antireflection film surface) is preferably equal to or greater than the thickness of the layer 13 containing a block copolymer formed on the substrate surface. The height of the guide pattern from the substrate surface (or antireflection film surface) is preferably adjusted as appropriate according to the thickness of the resist film formed by applying a resist composition for forming the guide pattern.

[Brief description of resist composition]
The resist composition for forming the guide pattern is not particularly limited as long as it has the structural unit (a1), and a block copolymer can be selected from resist compositions generally used for forming a resist pattern and modifications thereof. Those having affinity with any of the polymers constituting can be appropriately selected and used. Examples of the resist composition include a resist composition that generates an acid upon exposure and changes its solubility in a developer due to the action of the acid.
Examples of the alkali development positive resist composition include a resist composition that generates an acid upon exposure and has increased solubility in an alkali developer due to the action of the acid. Under the present circumstances, the resin component (base material component) which comprises this resist composition may contain the structural unit which generate | occur | produces an acid by exposure and increases the solubility with respect to an alkali developing solution by the effect | action of an acid. Details of the alkali development positive resist composition will be described later.
Examples of the solvent-developed negative resist composition include resist compositions that generate an acid upon exposure and have a reduced solubility in an organic developer due to the action of the acid. Under the present circumstances, the resin component (base material component) which comprises this resist composition may contain the structural unit which generate | occur | produces an acid by exposure and the solubility with respect to an organic type developing solution reduces by the effect | action of an acid. . Details of the solvent developing negative resist composition will be described later.

When the resist composition contains a component (B ″) described later, in the subsequent phase separation step, heat treatment can be performed at a relatively low temperature of 100 to 270 ° C. -180 degreeC may be sufficient and 120-170 degreeC may be sufficient.
For this reason, in the pattern formation method of the present invention, an alkali development positive resist composition or a solvent development negative resist composition having no crosslinking agent is used by using a resist composition containing the component (B ″) described later. It is possible to further suppress the thermal sagging of the guide pattern formed by the heat treatment in the phase separation process.

[Method for Forming Layer Containing Block Copolymer]
A layer containing a block copolymer is formed on the support having the guide pattern on the surface by using a composition containing a block copolymer, which will be described later, so as to cover the bottom surface of the concave portion of the guide pattern. At this time, it is preferable to form a layer containing the block copolymer so as to cover not only the bottom surface but also the side surface (side wall) of the recess. The method for forming this layer is not particularly limited, and known methods can be applied. For example, the block copolymer-containing composition is applied onto the substrate 11 on which the antireflection film 12 and the guide pattern 14 are formed using a spinner or the like.

The thickness of the layer 13 containing the block copolymer depends on the molecular weight (polymer period) of the block copolymer, and is generally preferably applied in the range of 0.5 to 4.0 times the polymer period.
In the present invention, the thickness of the layer 13 containing the block copolymer may be sufficient to cause phase separation. The lower limit of the thickness is not particularly limited, but is preferably 3 nm or more, and more preferably 5 nm or more in consideration of the strength of the nanostructure that can form the final target pattern. The upper limit value of the thickness is not particularly limited, but usually the thickness (height) of the guide pattern 14 is the upper limit value, and is preferably 1 μm or less.

<Phase separation step (step 2)>
Hereinafter, the phase separation process may be referred to as “process 2”. Step 2 is a step of phase-separating the layer containing the block copolymer obtained in Step 1.
By heat-treating the layer 13 containing a block copolymer, blocks having similar physicochemical properties are aggregated, and blocks having different physicochemical properties are excluded from each other. Phase separation can be achieved. At this time, it is preferable to form a phase separation structure in which at least a part of the surface of the support is exposed by selective removal of the block copolymer in a subsequent step. The phase-separated structure can form a periodic structure reflecting the properties, lengths, and arrangement of each block in the block copolymer. As an example thereof, there is a striped pattern structure (striped structure) having periodicity in the vertical direction with respect to two opposite sides of the guide patterns arranged opposite to each other as shown in FIG.

The temperature of the heat treatment is preferably higher than the glass transition temperature of the layer 13 containing the block copolymer to be used and lower than the thermal decomposition temperature. For example, when the block copolymer is PS-PMMA (Mw: 18k-18k), it is preferable to perform heat treatment at 160 to 270 ° C. for 30 to 3600 seconds. When the layer containing the block copolymer contains the component (B ″) described later, the glass transition temperature of the layer containing the block copolymer is lowered, so that the heat treatment can be performed at a lower temperature. Phase separation can be performed by heat treatment at ˜180 ° C. for 10 to 600 seconds.
The heat treatment is preferably performed in a gas having low reactivity such as nitrogen.

<Step of selectively removing (step 3)>
Hereinafter, the step of selectively removing may be referred to as “step 3”. Step 3 is a step of selectively removing a phase composed of at least one block among a plurality of types of blocks constituting the block copolymer from the structure in which the layer containing the block copolymer is phase-separated in Step 2. is there. By this selective removal, a final target pattern is obtained. The final target pattern can have a nanoscale periodic structure reflecting the phase separation structure. In this case, the final target pattern may be referred to as a nanostructure.

In the following description, among the blocks constituting the block copolymer, after the block P _A blocks not be selectively removed in step, a block which is selectively removed may be referred to as a block P _B. For example, after phase-separating a layer containing PS-PMMA block copolymer, a phase composed of PMMA is selectively removed by performing oxygen plasma treatment, hydrogen plasma treatment, or the like on the layer. In this case, PS is a block _{P A,} PMMA is _{P B} block.
In the example shown in FIG. 1, the phase of the separation structure comprises a block copolymer on the substrate after forming the layer 13, is selectively removed (low at least some of the blocks of the phase in consisting of block P _B Molecular weight).

Such selective removal process preferentially or towards the block P _B than P _A block, selectively only block P _B, as long as the process capable of decomposing and removing, the invention is not particularly limited from among the techniques used for removal of the resin film, depending on the type of block P _a and P _B block can be performed appropriately selected. Also, when the pre-neutralization film is formed on the substrate surface is preferably removed similarly to phase consisting of the neutralized film also block P _B. Examples of such removal treatment include oxygen plasma treatment, ozone treatment, UV irradiation treatment, thermal decomposition treatment, and chemical decomposition treatment.

Among the layers 13 consisting of a block copolymer, a substrate having a pattern formed by the phase 13b consisting of P _A block is left after selective removal can be used as it is, by performing the further heat treatment, the pattern The shape (nanostructure) can also be changed. Specifically, the heat treatment temperature, the block copolymer above the glass transition temperature of the used, so long and the thermal decomposition temperature or lower, the heat flow, it is possible to increase the size of the block P _A. Further, it is possible to heat treatment temperature, the block copolymer above the glass transition temperature of the used and if the thermal decomposition temperature or higher, the heat shrink, reducing the size of the block P _A. The heat treatment temperature is preferably not less than the glass transition temperature of the block copolymer to be used and less than the thermal decomposition temperature. The heat treatment is preferably performed in a gas having low reactivity such as nitrogen.

<< Composition Containing Block Copolymer >>
The block copolymer-containing composition that can be suitably used in the pattern forming method of the present invention is described in detail below.

<Solvent that dissolves block copolymer>
The block copolymer-containing composition preferably contains an organic solvent that dissolves the block copolymer.
As said organic solvent, the organic solvent currently used for the conventional block copolymer containing composition is applicable.
Specific examples of the organic solvent are not particularly limited as long as they can dissolve or disperse each component of the composition and form a uniform solution in which precipitation or the like hardly occurs. As a known solvent or an organic solvent for a polymer compound, one or two or more kinds of known solvents 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, ethylcyclohexane, etc. can be mentioned.

As said organic solvent, the organic solvent of the said example may be used independently, and 2 or more types may be mixed and used for it.
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. 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 still more preferably 3. : 7 to 7: 3.
In addition, as the organic solvent, 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 organic solvent is preferably a compound that does not correspond to the component (B ″) described later. When the organic solvent is a mixed solvent, the compound to be mixed does not correspond to the component (B ″) described later. It is preferable that

<Content of solvent in the composition>
The content of the organic solvent in the block copolymer-containing composition is not particularly limited, and can be applied to the guide pattern formed on the substrate, or can be injected or filled in the guide pattern. The concentration is appropriately set according to the coating film thickness. Usually, the solid content concentration in the composition is preferably 0.1 to 30% by mass, more preferably 0.2 to 25% by mass, and further preferably 0.3 to 20% by mass. preferable.

<Block copolymer: (Ap) component>
The block copolymer-containing composition contains a block copolymer in which a plurality of types of blocks are bonded. Here, the block copolymer is a polymer in which a plurality of types of blocks are bonded. There may be two types of blocks constituting the block copolymer, or three or more types.
The plurality of types of blocks constituting the block copolymer are not particularly limited as long as they are combinations that cause phase separation, but are preferably combinations of blocks that are incompatible with each other. Moreover, it is preferable that the phase which consists of at least 1 type block in the multiple types of block which comprises a block copolymer is a combination which can be selectively removed easily rather than the phase which consists of other types of block.

  As the block copolymer, for example, a block copolymer in which a block containing a structural unit derived from styrene or a derivative thereof and a block containing a structural unit derived from a (meth) acrylate ester are combined; from styrene or a derivative thereof A block copolymer comprising a block containing a structural unit derived from a block containing a structural unit derived from siloxane or a derivative thereof; and a block containing a structural unit derived from an alkylene oxide and a (meth) acrylate And a block copolymer in which a block containing a structural unit derived from is bonded.

  Examples of the (meth) acrylic acid ester include those in which a substituent such as an alkyl group or a hydroxyalkyl group is bonded to the carbon atom of (meth) acrylic acid. Examples of the alkyl group used as a substituent include a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, ( Nonyl methacrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, anthracene (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid 3, Examples include 4-epoxycyclohexylmethane and (meth) acrylic acid propyltrimethoxysilane.

  Examples of the styrene derivative include 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene, 4-n-octylstyrene, 2,4,6-trimethylstyrene, 4-methoxystyrene, 4-t-butoxystyrene, 4-hydroxystyrene, 4-nitrostyrene, 3-nitrostyrene, 4-chlorostyrene, 4-fluorostyrene, 4-acetoxyvinylstyrene, vinylcyclohexane, 4-vinylbenzyl chloride, 1- Examples thereof include vinyl naphthalene, 4-vinyl biphenyl, 1-vinyl-2-pyrrolidone, 9-vinyl anthracene, vinyl pyridine and the like.

Examples of the siloxane derivative include dimethylsiloxane, diethylsiloxane, diphenylsiloxane, methylphenylsiloxane, and the like.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, isopropylene oxide, and butylene oxide.

  In the present invention, it is preferable to use a block copolymer in which a block containing a structural unit derived from styrene or a derivative thereof and a block containing a structural unit derived from a (meth) acrylic ester are combined. Specifically, polystyrene-polymethyl methacrylate (PS-PMMA) block copolymer, polystyrene-polyethyl methacrylate block copolymer, polystyrene- (poly-t-butyl methacrylate) block copolymer, polystyrene-polymethacrylic acid block copolymer, polystyrene-poly. Examples thereof include a methyl acrylate block copolymer, a polystyrene-polyethyl acrylate block copolymer, a polystyrene- (poly-t-butyl acrylate) block copolymer, and a polystyrene-polyacrylic acid block copolymer. In the present invention, it is particularly preferable to use a PS-PMMA block copolymer.

The mass average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of each block constituting the block copolymer is not particularly limited as long as it is a size capable of causing phase separation. To 50,000,000 are preferable, 5,000 to 400,000 are more preferable, and 5,000 to 300,000 are more preferable.
Further, the dispersity (Mw / Mn) of the block copolymer is preferably 1.0 to 3.0, more preferably 1.0 to 1.5, and still more preferably 1.0 to 1.2. In addition, Mn shows a number average molecular weight.

<Compound: (B ") component>
In addition to the organic solvent, the block copolymer-containing composition preferably further contains a compound having a vapor pressure at 20 ° C. of 0.05 hPa or less and a freezing point of 25 ° C. or less. Hereinafter, the compound is sometimes referred to as component (B ″).
Here, the “vapor pressure at 20 ° C.” refers to the pressure of the vapor phase in equilibrium with the liquid phase or solid phase at 20 ° C.
By using a compound having a specific vapor pressure as the component (B ″), it is possible to reduce the glass transition temperature (Tg) of the layer composed of the block copolymer in the pattern forming method of the present invention, and at a relatively low temperature. Even when annealing is performed, a good pattern can be formed. The vapor pressure at 20 ° C. of the component (B ″) is not particularly limited as long as it is 0.05 hPa or less, but from 0 hPa Is greater than 0.04 hPa, preferably greater than 0 hPa, more preferably less than 0.03 hPa, more preferably greater than 0 hPa and less than 0.01 hPa.

  In addition, since the freezing point of the component (B ″) is 25 ° C. or less, the component (B ″) becomes a liquid compound at room temperature of at least about 25 ° C. When a layer containing a block copolymer is formed thereon, a layer containing a block copolymer having good properties can be formed. The freezing point of the component (B ″) is preferably 25 ° C. or lower, preferably 20 ° C. or lower, more preferably 10 ° C. or lower, and further preferably 0 ° C. or lower. "Refers to the temperature at which a liquid phase substance maintains equilibrium with the solid phase at a standard atmospheric pressure of 1013.25 hPa.

  Further, as the component (B ″), the static surface tension is preferably 30 mN / m or more, more preferably 30 to 65 mN / m, and further preferably 30 to 50 mN / m. When the target surface tension is 30 mN / m or more, the layer containing the block copolymer containing the component (B ″) becomes dense. In particular, if a layer containing a block copolymer is formed on a support having a guide pattern, the static surface tension is small, so that the layer containing the block copolymer can easily enter the fine voids of the guide pattern. This is preferable because a fine pattern (final target pattern) faithful to the guide pattern can be obtained. Here, “static surface tension” refers to a static surface tension measured by a dropping method at 20 ° C.

  As the component (B ″), specifically, alcohols such as benzyl glycol, glycerin, phenyl diglycol and benzyl diglycol, and esters such as triacetin are preferable, and phenyl diglycol is particularly preferable.

  The mass average molecular weight (Mw) of the component (B ″) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 600 or less, more preferably 50 to 600, and even more preferably 100 to 600. By setting the molecular weight within the above range, good thermal fluidity can be obtained even at a low temperature.

As the component (B ″), one type may be used alone, or two or more types may be used in combination.
When a plurality of types of component (B ″) are used in combination, a combination of alcohols and esters is preferable.
The content of the (B ″) component in the pattern forming method of the present invention is not particularly limited, but the ratio of the (B ″) component to the total of the (B ″) component and the organic solvent is 0.1 to It is preferably 40% by mass, more preferably 0.3 to 35% by mass, and further preferably 0.6 to 30% by mass. Here, the organic solvent is a component (B ″). It is a different organic solvent.
In addition, the total amount of the component (B ″) and the organic solvent used in the composition of the present invention is not particularly limited, and can be applied after the desired application at a concentration at which the block copolymer-containing composition can be applied to a support or the like. It can be determined appropriately according to the film thickness and the like.

When the component (B ″) is contained in the block copolymer-containing composition, the difference (ΔSP value) between the SP value of the organic solvent constituting the composition and the SP value of the component (B ″) is 0. It is preferable that it is in the range of -5, and it is more preferable that the ΔSP value is 0-2.5.
Here, the “SP value” is a solubility parameter, and the smaller the difference (ΔSP value) between the component (B ″) and the organic solvent, the better the compatibility and the better the pattern.

  The block copolymer-containing composition may optionally contain miscible additives such as an additional resin for improving the performance of the neutralized film, a surfactant for improving the coating property, a dissolution inhibitor, A plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, a sensitizer, a base proliferating agent, a basic compound, and the like can be appropriately added and contained.

<< Resist composition suitable for alkali development process >>
In the pattern forming method of the present invention, a known positive resist composition can be applied as a resist composition for forming a guide pattern. Examples of suitable positive resist compositions are shown below.

  The positive resist preferably contains a base material component whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component that generates an acid upon exposure. In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the acid generator component, the polarity is increased by the action of the acid, and the solubility in an alkaline developer is increased. Therefore, in the formation of the guide pattern, when selective exposure is performed on the resist film obtained using the resist composition, the solubility of the exposed portion of the resist film in the alkaline developer increases. Since the unexposed portion remains hardly soluble in alkali and does not change, by performing alkali development, the exposed portion is removed and a guide pattern is formed. In addition, as the positive resist composition, those containing a base material component whose solubility in an alkaline developer is increased by the action of an acid and which generates an acid upon exposure can be used.

<(A) component>
The alkali development positive resist composition used in the pattern forming method of the present invention is a positive resist composition (hereinafter referred to as component (A)) whose solubility in an alkaline developer is increased by the action of an acid, and an acid upon exposure. It is preferable that an acid generator component (hereinafter referred to as “component (B)”) is generated. Here, the component (A) preferably contains the structural unit (a1).
Further, the alkali development positive resist composition used in the pattern forming method of the present invention is a base material component (hereinafter referred to as (A ′)) which generates an acid upon exposure and increases the solubility in an alkali developer by the action of the acid. May be included). The substrate component (A ′) preferably contains a resin component (hereinafter referred to as (A1 ′) component) having a structural unit (hereinafter referred to as component (a6)) that generates an acid upon exposure.
Furthermore, the alkali development positive resist composition used in the pattern forming method of the present invention may contain the component (A ′) and the component (B).
The alkali development positive resist composition may be a resist composition containing both the component (A) and the component (A ′). Specifically, a resist composition containing both the structural unit (a1) and the structural unit (a6), or the structural units (a1) and (a6) and the structural units (a2), (a3), (a4), Examples thereof include resist compositions containing any one or more selected from the components (a5) and (B).

In the present specification, the “base component” means an organic compound having a film forming ability.
As the base material component, an organic compound having a molecular weight of 500 or more is usually used. When the molecular weight is 500 or more, it has a sufficient film forming ability and can easily form a nano-level resist pattern.
“Organic compounds having a molecular weight of 500 or more” 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, “polymer compound” refers to a polymer having a molecular weight of 1000 or more.
In the case of a polymer compound, the “molecular weight” is a polystyrene-equivalent mass average molecular weight measured by GPC (gel permeation chromatography).

(Structural unit (a1))
The component (A) preferably contains the 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 groups 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).
Here, “acid-dissociable group” means
(I) an acid-dissociable group capable of cleaving a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by the action of an acid, or
(Ii) a group capable of cleaving a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by further decarboxylation reaction after partial bond cleavage by the action of an acid ,
Both.
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 organic developer, the solubility decreases.

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.
Among the polar groups, examples of the acid dissociable group that protects a carboxy group or a hydroxyl group include an acid dissociable group represented by the following general formula (a1-r-1) (hereinafter referred to as “acetal acid dissociable for convenience”). Group ”).

［式中、Ｒａ’^１、Ｒａ’^２は水素原子またはアルキル基、Ｒａ’^３は炭化水素基、Ｒａ’^３は、Ｒａ’^１、Ｒａ’^２のいずれかと結合して環を形成してもよい。］

[Wherein, Ra ′ ¹ and Ra ′ ² are hydrogen atoms or alkyl groups, Ra ′ ³ is a hydrocarbon group, and Ra ′ ³ may be bonded to either Ra ′ ¹ or Ra ′ ² to form a ring. Good. ]

In formula (a1-r-1), Ra ′ ¹ and Ra ′ ² are exemplified as the substituents that may be bonded to the α-position carbon atom in the description of the α-substituted acrylate ester. Examples thereof include the same as the alkyl group, preferably a methyl group or an ethyl group, and most preferably a methyl group.

The hydrocarbon group for Ra ′ ³ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms; a linear or branched alkyl group is preferable, specifically , Methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, 1,1-dimethylethyl group, 1,1-diethylpropyl group 2,2-dimethylpropyl group, 2,2, -dimethylbutyl group and the like can be mentioned.
When Ra ′ ³ is bonded to either Ra ′ ¹ or Ra ′ ² to form a ring, 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.

  Among the polar groups, examples of the acid dissociable group that protects the carboxy group include an acid dissociable group represented by the following general formula (a1-r-2) (the following formula (a1-r-2) Among the acid dissociable groups represented by), those composed of an alkyl group may hereinafter be referred to as “tertiary alkyl ester type acid dissociable groups” for convenience).

［式中、Ｒａ’^４〜Ｒａ’^６は炭化水素基であり、Ｒａ’^５、Ｒａ’^６は互いに結合して環を形成してもよい。］

[Wherein, Ra ′ ^{4 to} Ra ′ ⁶ are hydrocarbon groups, and Ra ′ ⁵ and Ra ′ ⁶ may be bonded to each other to form a ring. ]

As the hydrocarbon group for Ra ′ ^{4 to} Ra ′ ^6, the same groups as those described above for Ra ′ ³ can be mentioned. Ra ′ ⁴ is preferably an alkyl group having 1 to 5 carbon atoms. In the case where Ra ′ ⁵ and Ra ′ ⁶ are bonded to each other to form a ring, a group represented by general formula (a1-r2-1) shown below can be given.

［式中、Ｒａ’^１０は炭素数１〜１０のアルキル基、Ｒａ’^１１はＲａ^１０が結合した炭素原子と共に脂肪族環式基を形成する基を示す。］

[Wherein, Ra ′ ¹⁰ represents an alkyl group having 1 to ¹⁰ carbon atoms, and Ra ′ ¹¹ represents a group that forms an aliphatic cyclic group together with the carbon atom to which Ra ¹⁰ is bonded. ]

  Specific examples of the formula (a1-r2-1) are given below.

  Examples of the acid dissociable group for protecting the hydroxyl group among the polar groups include, for example, an acid dissociable group represented by the following general formula (a1-r-3) (hereinafter referred to as “tertiary alkyloxycarbonyl acid for convenience”). Sometimes referred to as a “dissociable group”).

［式中、Ｒａ’^７〜Ｒａ’^９はアルキル基を示す。］

[Wherein, Ra ′ ^{7 to} Ra ′ ⁹ represent an alkyl group. ]

In formula (a1-r-3), Ra ′ ^{7 to} Ra ′ ⁹ are preferably an alkyl group having 1 to 5 carbon atoms, and more preferably 1 to 3 groups.
Moreover, it is preferable that the total carbon number of each alkyl group is 3-7, it is more preferable that it is 3-5, and it is most preferable that it is 3-4.

  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.

Among the above, the structural unit (a1) is preferably 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.
As the structural unit (a1), structural units represented by general formula (a1-1) shown below are preferred.

［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る。Ｖａ^１は２価の炭化水素基であり、ｎ_ａ１はそれぞれ独立に０〜２であり、
Ｒａ^１は上記式（ａ１−ｒ−１）〜（ａ１−ｒ−２）で表される酸解離性基である。］

[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. Va ¹ is a divalent hydrocarbon group, n _a1 is independently 0 to 2,
Ra ¹ is an acid dissociable group represented by the above formulas (a1-r-1) to (a1-r-2). ]

In the formula (a1-1), the alkyl group having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, or propyl. Group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. The halogenated alkyl group having 1 to 5 carbon atoms 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 halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group in terms of industrial availability.
The hydrocarbon group for Va ¹ 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 a divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is usually preferably saturated.
More specifically, 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.

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. As said monocycloalkane, a C3-C6 thing is preferable, and a cyclopentane, a cyclohexane, etc. are mentioned specifically ,. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ 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.
Specific examples of the formula (a1-1) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

  The proportion of the structural unit (a1) in the component (A) is preferably from 20 to 80 mol%, more preferably from 20 to 75 mol%, more preferably from 25 to 70 mol%, based on all structural units constituting the component (A). Is more preferable. By setting it to the lower limit value or more, a guide pattern can be easily formed, and lithography properties such as sensitivity, resolution, and LWR are also improved. Moreover, the balance with another structural unit can be taken by making it below an upper limit.

(Structural unit (a2))
The component (A) preferably further has a structural unit (a2) containing a lactone-containing cyclic group in addition to the structural unit (a1). The lactone cyclic group of the structural unit (a2) is effective in enhancing the adhesion of the resist film to the substrate when the component (A) is used for forming the resist film.
In addition, when the structural unit (a1) includes a lactone-containing cyclic group in the structure, the structural unit also corresponds to the structural unit (a2). However, such a structural unit is included in the structural unit (a1). Applicable and not applicable to the structural unit (a2).

The “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —O—C (═O) — in the ring skeleton. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
The lactone-containing cyclic group in the structural unit (a2) is not particularly limited, and any lactone-containing cyclic group can be used. Specific examples include those represented by the following general formulas (a2-r-1) to (a2-r-7).

［式中、Ｒａ’^２１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、−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；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ｎ’は０〜２の整数でありｍ’は０または１である。］

[Wherein, Ra ′ ²¹ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group. Yes; R ″ is a hydrogen atom or an alkyl group; 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, and n ′ is 0 to 2 It is an integer and m ′ is 0 or 1. ]

Specific examples of the structural units represented by general formulas (a2-r-1) to (a2-r-7) are given below.

The structural unit (a2) contained in the component (A) may be one type or two or more types.
When the component (A) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 80 mol% with respect to the total of all the structural units constituting the component (A). It is more preferably 10 to 70 mol%, further preferably 10 to 65 mol%, particularly preferably 10 to 60 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting it to the upper limit value or less, balance with other structural units can be achieved. The lithography characteristics and pattern shape of the film are improved.

(Structural unit (a3))
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (except for those corresponding to the structural units (a1) and (a2) described above).
When the component (A) has the structural unit (a3), the hydrophilicity of the component (A) is increased, which contributes to the improvement of the 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.

The structural unit (a3) contained in the component (A) may be one type or two or more types.
In the component (A), 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 (A). 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.

(Structural unit (a4))
The component (A) may contain other structural units (a4) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic cyclic group is preferable. Examples of the cyclic group include those similar to those exemplified for the structural unit (a1), such as for ArF excimer laser, for KrF excimer laser (preferably for ArF excimer laser), etc. A number of hitherto known materials can be used as the resin component of the resist composition.
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 having the structures of the following general formulas (a4-1) to (a4-6).

［式中、Ｒ^αは前記と同じである。］

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

  When the structural unit (a4) is contained in the component (A), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A). 10 to 20 mol% is more preferable.

(Structural unit (a5))
The component (A) preferably further contains the structural unit (a5). The —SO ₂ — containing cyclic group of the structural unit (a5) is effective for enhancing the adhesion of the resist film to the substrate when the component (A) is used for forming the resist film.
In addition, when the structural unit (a1) includes a —SO ₂ — containing cyclic group in the structure, the structural unit also corresponds to the structural unit (a5). It corresponds to a1) and does not correspond to the structural unit (a5).
Here, the “—SO ₂ -containing cyclic group” refers to a cyclic group containing a ring containing —SO ₂ — in the ring skeleton, specifically, a sulfur atom in —SO ₂ — ( S) is a cyclic group that forms part of the ring skeleton of the cyclic group. The ring containing —SO ₂ — in the ring skeleton is counted as the first ring, and when it is only the ring, it is a monocyclic group, and when it has another ring structure, it is a polycyclic group regardless of the structure. Called. The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
-SO ₂ - containing cyclic group, in particular, -O-SO ₂ - within the ring skeleton cyclic group containing, i.e. -O-SO ₂ - -O-S- medium is a part of the ring skeleton A cyclic group containing a sultone ring to be formed is preferable. More specific examples of the —SO ₂ — containing cyclic group include structural units represented by the following general formulas (a5-r-1) to (a5-r-4).

［式中、Ｒａ’^５１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、−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；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ｎ’は０〜２の整数である。］

[Wherein, Ra ′ ⁵¹ independently represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group. Yes; R ″ is a hydrogen atom or an alkyl group; 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, and n ′ is 0 to 2 It is an integer. ]

In general formulas (a5-r-1) to (a5-r-4), A ″ represents an oxygen atom (—O—) or a sulfur atom (—S—), and may have 1 to 5 carbon atoms. The alkylene group having 1 to 5 carbon atoms in A ″ is preferably a linear or branched alkylene group, a methylene group, an ethylene group, an n-propylene group, An isopropylene group etc. are mentioned.
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.
As the alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in Ra ′ ⁵¹ , the —SO ₂ — containing cyclic group is as described above. Examples of the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group mentioned as the substituents that may be included are the same.
Specific examples of cyclic groups represented by the general formulas (a5-r-1) to (a5-r-4) are shown below. In the formula, “Ac” represents an acetyl group.

As the —SO ₂ — containing cyclic group, among the above, a group represented by the general formula (a5-r-1) is preferable, and the chemical formulas (r-sl-1-1) and (r-sl— 1-19), at least one selected from the group consisting of groups represented by (r-sl-3-1) and (r-sl-4-1) is more preferable. The group represented by sl-1-1) is most preferred.

The structural unit (a5) is not particularly limited as long as it has a —SO ₂ — containing cyclic group, but may be a structural unit represented by the general formula (a5-1). preferable.

(Structural unit (a6))
The alkali development positive resist composition used in the pattern forming method of the present invention generates an acid upon exposure and is a base component (hereinafter referred to as (A ′) component) whose solubility in an alkali developer is increased by the action of the acid. .) May be contained. The substrate component (A ′) particularly preferably contains a resin component (hereinafter referred to as (A1 ′) component) having a structural unit (hereinafter referred to as (a6) component) that generates an acid upon exposure. .
The structural unit (a6) preferably includes a structural unit containing a group represented by the following general formula (a6c-1) or (a6a-1).
In this invention, since the heat resistance of a resist pattern improves because the resin component contains the structural unit ((a6) component) which generate | occur | produces an acid by exposure, it is preferable. The resist pattern containing the component (a6) in the resin component is considered to be less prone to thermal sagging even if the annealing temperature for phase separation of the block copolymer is higher than that of the resist pattern not containing the component (a6). It is done.

［式中、Ｑ^１、Ｑ^２はそれぞれ独立に、単結合又は２価の連結基であり、Ｒ^３、Ｒ^４、Ｒ^５はそれぞれ独立に有機基であり、Ｒ^４、Ｒ^５は相互に結合して式中のイオウ原子と共に環を形成していてもよく、Ｖ⁻は対アニオンである。Ａ⁻はアニオンを含む有機基であり、Ｍ^ｍ＋は有機カチオンであり、ｍは１〜３の整数である。］

[Wherein, Q ¹ and Q ² are each independently a single bond or a divalent linking group, R ³ , R ⁴ and R ⁵ are each independently an organic group, and R ⁴ and R ⁵ are It may be bonded to form a ring with the sulfur atom in the formula, and V ⁻ is a counter anion. A ⁻ is an organic group containing an anion, M ^{m +} is an organic cation, and m is an integer of 1 to 3. ]

{Monomer having a group represented by the formula (a6c-1)}
In formula (a6c-1), Q ¹ represents a single bond or a divalent linking group.
No particular limitation is imposed on the divalent linking group for Q ^1, a divalent hydrocarbon group which may have a substituent group, and a divalent linking group containing a hetero atom as preferred.

(Divalent hydrocarbon group which may have a substituent)
The hydrocarbon group as the divalent linking 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 may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group having 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 8 carbon atoms, and still more preferably 1 to 5 carbon atoms.
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 (a group or atom other than a hydrogen atom) that replaces a hydrogen atom. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxo group (═O).

As the aliphatic hydrocarbon group containing a ring in the structure, a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure (excluding two hydrogen atoms from the aliphatic hydrocarbon ring) Group), a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and the cyclic aliphatic hydrocarbon group is a linear or branched chain fatty acid. Group intervening in the middle of the group hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include those described above.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be polycyclic or monocyclic. As the monocyclic aliphatic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic aliphatic 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, Examples include norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent (a group or atom other than a hydrogen atom) that replaces a hydrogen atom. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxo group (═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 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 groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
In the cyclic aliphatic hydrocarbon group, a part of carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. As the substituent containing the hetero atom, —O—, —C (═O) —O—, —S—, —S (═O) ₂ —, and —S (═O) ₂ —O— are preferable.

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

(Divalent linking group containing a hetero atom)
The hetero atom in the divalent linking group containing a hetero atom 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.

When Q ¹ is a divalent linking group containing a hetero atom, preferred examples of the linking group include —O—, —C (═O) —O—, —C (═O) —, —O—C. (═O) —O—, —C (═O) —NH—, —NH—, —NH—C (═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-, the formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 - A group represented by C (═O) —O—, — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — In the formula, Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m ′ is an integer of 0 to 3. ] Etc. are mentioned.
When Q ¹ is —C (═O) —NH—, —NH—, —NH—C (═NH) —, the H may be substituted with a substituent such as an alkyl group or acyl. 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 -O -, - Y 21 -C (= O) -O -, - [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 those similar to the “divalent hydrocarbon group optionally having substituent (s)” mentioned in the description of the divalent linking group.
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.

Q ¹ in the present invention is a single bond, an ester bond [—C (═O) —O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. It is preferable.

In formula (a6c-1), R ³ , R ⁴ and R ⁵ are each independently an organic group, and R ⁴ and R ⁵ may be bonded to each other to form a ring together with the sulfur atom in the formula. .
Each is independently an organic group.
The organic group of R ^{3 to} R ^{5 is} a group containing a carbon atom, and includes atoms other than carbon atoms (for example, hydrogen atom, oxygen atom, nitrogen atom, sulfur atom, halogen atom (fluorine atom, chlorine atom, etc.)). You may have.

Specific examples of the organic group for R ³ include an alkylene group which may have a substituent and an arylene group which may have a substituent.
Examples of the alkylene group which may have a substituent in R ³ include an unsubstituted alkylene group, a substituted alkylene group in which part or all of the hydrogen atoms of the unsubstituted alkylene group are substituted with a substituent, and the like. Is mentioned.
The unsubstituted alkylene group may be linear, branched or cyclic. From the viewpoint of excellent resolution, an alkylene group having 1 to 10 carbon atoms is preferable, and an alkylene group having 1 to 5 carbon atoms is more preferable. Specifically, methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group, n-pentylene group, cyclopentylene group, hexylene group, cyclohexylene group, nonylene group, decylene group. Etc.

Examples of the substituent that the substituted alkylene group has include a halogen atom, an oxo group (═O), a cyano group, an alkyl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C (═O) —O—R ⁷ ″, ^{-O-C (= O) -R} 8 ", -O-R 9", an aryl group ^.R 7 ^", R ^8", the ^{R 9} "are each independently, a hydrogen atom or a hydrocarbon group is there.
Among these, examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom, and a fluorine atom is preferable.

The alkyl group as a substituent in the substituted alkylene group may be linear, branched or cyclic. The carbon number is preferably 1-30.
Among them, the linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched 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.
The cyclic alkyl group may be monocyclic or polycyclic. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
The cyclic alkyl group is preferably a polycyclic group, preferably a group obtained by removing one or more hydrogen atoms from polycycloalkane, and most preferably a group obtained by removing one or more hydrogen atoms from adamantane.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

Examples of the alkoxyalkyloxy group as a substituent in the substituted alkylene group include:
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. ]
The group represented by these is mentioned.
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.

Examples of the alkoxycarbonylalkyloxy group as a substituent in the substituted alkylene group include:
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. ]
The group represented by these is mentioned.
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.
The tertiary alkyl group for R ⁵⁶ includes a 2-methyl-2-adamantyl group, a 2- (2-propyl) -2-adamantyl group, a 2-ethyl-2-adamantyl group, and a 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 can be mentioned.

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 formulas (L1) to (L5) and (S1) to (S4) described later. 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 oxo group (═O), etc. Is mentioned.
As for R ⁵⁶ ′, the hydrogen atom in the aliphatic cyclic group is specifically substituted with a hetero atom, specifically, the hydrogen atom in the aliphatic cyclic group is substituted with an oxo group (═O), etc. Is mentioned.

R ⁷ ″ in —C (═O) —O—R ⁷ ″ represents a hydrogen atom or a hydrocarbon group.
The hydrocarbon group for R ⁷ ″ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group. Any of these may be used.

The saturated hydrocarbon group for R ⁷ ″ may be linear, branched or cyclic, or a combination thereof.
1-25 are preferable, as for carbon number of a linear or branched saturated hydrocarbon group, 1-15 are more preferable, and 4-10 are more preferable.
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.
The branched saturated hydrocarbon radicals, for example, tertiary alkyl groups mentioned in the description of the R ^56. Examples of branched saturated hydrocarbon groups other than tertiary alkyl groups include 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 oxo group (═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 number of carbon atoms of the cyclic saturated hydrocarbon group in R ⁷ ″ is preferably 3 to 20. The cyclic saturated hydrocarbon group may be either a polycyclic group or a monocyclic group. A group in which one hydrogen atom is removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. More specifically, cyclopentane, cyclohexane, Examples thereof include monocycloalkanes such as cycloheptane and cyclooctane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
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, an alkyl group having 1 to 5 carbon atoms, and the like. .
The saturated hydrocarbon group for R ⁷ ″ may be a combination of a linear or branched saturated hydrocarbon group and a cyclic saturated hydrocarbon group.
As a combination of a linear or branched saturated hydrocarbon group and a cyclic saturated hydrocarbon group, a cyclic saturated hydrocarbon group as a substituent is bonded to the linear or branched saturated hydrocarbon group. Examples include a group (for example, 1- (1-adamantyl) methyl group), a group in which a linear or branched saturated hydrocarbon group is bonded to a cyclic saturated hydrocarbon group as a substituent.

The aliphatic unsaturated hydrocarbon group for R ⁷ ″ is preferably linear or branched. Examples of the linear aliphatic unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and butynyl. Examples of the branched aliphatic unsaturated hydrocarbon group include 1-methylpropenyl group, 2-methylpropenyl group, etc. These linear or branched aliphatic unsaturated groups. The saturated hydrocarbon group may have a substituent, and examples of the substituent are the same as those exemplified as the substituent which the linear or branched alkyl group may have. Can be mentioned.

The aromatic hydrocarbon group for R ⁷ ″ is a monovalent hydrocarbon group having at least one aromatic ring and may have a substituent.
The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are more preferable, and 6-12 are especially preferable. However, the carbon number does not include the carbon number in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms; etc. Is mentioned. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specifically, the aromatic hydrocarbon group is a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group); the aromatic hydrocarbon ring or aromatic heterocycle Groups in which one of the ring 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, heteroarylalkyl group); and the like. The number of carbon atoms of the alkylene group that replaces the hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1. .
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxo group (═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 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 groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

Among the above, R ⁷ ″ is preferably a hydrogen atom, a saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group because of excellent lithography characteristics and resist pattern shape. Are more preferably a linear or branched saturated hydrocarbon group or a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms.

R ⁸ ″ in —O—C (═O) —R ⁸ ″ represents a hydrogen atom or a hydrocarbon group.
As R ⁸ ″, the same as R ⁷ ″ can be mentioned. Among them, a hydrogen atom, a saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group is preferable because of excellent lithography characteristics and resist pattern shape, and a hydrogen atom, a linear or branched group having 1 to 15 carbon atoms. A chain-like saturated hydrocarbon group or a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms is more preferable.

^{"R 9} in" ^{-O-R 9} is hydrogen atom or a hydrocarbon group.
Examples of R ⁹ ″ include the same as R ⁷ ″. Among them, a hydrogen atom, a saturated hydrocarbon group or an aliphatic unsaturated hydrocarbon group is preferable because of excellent lithography characteristics and resist pattern shape, and a hydrogen atom, a linear or branched group having 1 to 15 carbon atoms. A chain-like saturated hydrocarbon group or a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms is more preferable.
As the substituent, —O—R ⁹ ″ is preferably a hydroxyl group or 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- Most preferred is a butoxy group.

The aryl group as a substituent in the substituted alkylene 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 aryl group as the substituent may have a substituent. Examples of the substituent include the same substituents as those exemplified as the substituent which the aromatic hydrocarbon group for R ⁷ ″ may have.

In the formula (a6c-1), as the arylene group which may have a substituent for R ^3, an unsubstituted arylene group having 6 to 20 carbon atoms; a part of hydrogen atoms of the unsubstituted arylene group or Examples thereof include a substituted arylene group which is entirely substituted with a substituent.
The unsubstituted arylene group is preferably an arylene group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenylene group and a naphthylene group.
Examples of the substituent in the substituted arylene group include the same groups as those described above as the substituent in the substituted alkylene group. Specifically, among those listed as the substituent in the substituted alkylene group, a halogen atom, an oxo group (═O), a cyano group, an alkyl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C (═O ) —O—R ⁷ ″, —O—C (═O) —R ⁸ ″, —O—R ⁹ ″ (where R ⁷ ″, R ⁸ ″, R ⁹ ″ are independently hydrogen atom, saturated carbonization) A hydrogen group or an aliphatic unsaturated hydrocarbon group).

In formula (a6c-1), the organic groups of R ⁴ and R ⁵ are not particularly limited, but may be an aryl group which may have a substituent, or an alkyl which may have a substituent. And an alkenyl group optionally having a substituent.

Examples of the aryl group which may have a substituent in R ⁴ and R ⁵ include an unsubstituted aryl group having 6 to 20 carbon atoms; a part or all of the hydrogen atoms of the unsubstituted aryl group are substituent groups. Examples include substituted aryl groups.
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.
Examples of the substituent in the substituted aryl group include the same substituents as the substituents that the substituted arylene group may have.

Examples of the alkyl group in R ⁴ and R ⁵ include an unsubstituted alkyl group, a substituted alkyl group in which part or all of the hydrogen atoms of the unsubstituted alkyl group are substituted with a substituent, and the like.
The unsubstituted alkyl group may be linear, branched or cyclic. From the point which is excellent in resolution, a C1-C10 alkyl group is preferable and a C1-C5 alkyl group is more preferable. 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. .
Examples of the substituent in the substituted alkyl group include the same as those described as the substituent that the substituted alkylene group in R ³ may have.

Examples of the alkenyl group in R ⁴ and R ⁵ include an unsubstituted alkenyl group and a substituted alkenyl group in which part or all of the hydrogen atoms of the unsubstituted alkenyl group are substituted with a substituent.
The unsubstituted alkenyl group is preferably linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, and still 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.
Examples of the substituent in the substituted alkenyl group include the same groups as those described above as the substituent that the substituted alkylene group in R ³ may have.

In formula (a6c-1), R ⁴ and R ⁵ may be bonded to each other to form a ring together with the sulfur atom in the formula. The ring may be saturated or unsaturated. The ring may be monocyclic or polycyclic. For example, when one or both of R ⁴ and R ⁵ forming a ring is a cyclic group (cyclic alkyl group or aryl group), a polycyclic ring (fused ring) is formed by combining them. The
As the ring to be formed, one ring containing a sulfur atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring, particularly a 5- to 7-membered ring, including the sulfur atom. preferable.
The ring may have a hetero atom other than the sulfur atom to which R ⁴ and R ⁵ are bonded as an atom constituting the ring skeleton. Examples of the hetero atom include a sulfur atom, an oxygen atom, and a nitrogen atom.
Specific examples of the ring formed include, for example, thiophene ring, thiazole ring, benzothiophene ring, thianthrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, thioxanthone ring, thianthrene ring, phenoxathiin ring, tetrahydro A thiophenium ring, a tetrahydrothiopyranium ring, etc. are mentioned.

In formula (a6c-1), V ⁻ represents a counter anion.
The counter anion of V ⁻ is not particularly limited, and for example, those conventionally known as the anion part of the onium salt acid generator can be used as appropriate.
As V ⁻ , 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.
In the case where R ⁴ ″ is an alkyl group, examples of “R ⁴ ″ SO ₃ ⁻ ” 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.

X ³ -Q ^'- In the group represented by, ^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.

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

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

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

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

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

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

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

In the formula, examples of the alkylene group for Q ″, R ^{94 ′} and R ^{95 ′} include the same alkylene groups as those described above for R ^{91 to} R ⁹⁵ .
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 constituting the aliphatic hydrocarbon group for X ³ .

In the present invention, X ³ 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 aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is a group obtained by removing one or more hydrogen atoms from the polycycloalkane, and is represented by the formulas (L2) to (L6) and (S3) to (S4). Groups and the like are preferred.

Among the above, the R ^{4 "is,} X ³ -Q ^'as a halogenated alkyl group or a substituted group, - it is preferable to have a.
^'- if having, as the ^{R 4 ", X 3 -Q'} -Y 3 - X 3 -Q as a substituent in the Formula, Q ^{'and X 3} are as defined above, the ^{Y 3} substituent A C1-C4 alkylene group which may have or a C1-C4 fluorinated alkylene group which may have a substituent.] Is preferable.
X ³ -Q ^{'-Y 3} - In the group represented by the formula, the alkylene group of ^{Y 3,} wherein ^Q' include the same ones having 1 to 4 carbon atoms of the alkylene groups listed.
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.

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

［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 those listed as the substituents that may substitute part of the hydrogen atoms bonded to the carbon atoms constituting the ring structure of the aliphatic cyclic group in the description of X ³ above, The thing similar to what was mentioned as a substituent which may substitute the hydrogen atom couple | bonded with the aromatic ring which an aromatic hydrocarbon group has 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.

Also, V in the formula (a6c-1) ^- as, for example anion represented by the following general formula (b-3), the anion may be mentioned which are represented by the following general formula (b-4).

［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 (b-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 (b-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;

V in the formula (a6c-1) ^- as represented by the general formula ^"R 4" SO ₃ ^- "represented by anions (especially in, ^{R 4"} is ^{X 3} -Q ^'-Y 3 - is a group represented by The anions represented by the above formulas (b1) to (b9) are preferred.

Specific examples of the group represented by formula (a6c-1) are shown below. In the formula, V ⁻ is the same as described above.

The monomer having a group represented by the formula (a6c-1) is preferably a compound having an ethylenic double bond. When it has an ethylenic double bond, the polymer compound can be formed by cleaving the ethylenic double bond into a single bond in the polymerization reaction.
Examples of the compound having an ethylenic double bond include acrylic acid or an ester thereof in which a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the α-position carbon atom. Acrylamide or a derivative thereof optionally substituted with a substituent, a vinyl aromatic compound in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, a cycloolefin or a derivative thereof, a vinyl sulfonate, etc. Is mentioned. Among these, a hydrogen atom bonded to the α-position carbon atom may be substituted with an acrylic acid or an ester thereof, and a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. Acrylamide or a derivative thereof, and a vinyl aromatic compound in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent are preferable.

{Monomer having a group represented by the formula (a6a-1)}
In Formula (a6a-1), Q ² is a single bond or a divalent linking group, and is the same as Q ^{1 in} Formula (a6c-1).

In formula (a6a-1), A ⁻ represents an organic group containing an anion.
A ⁻ is not particularly limited as long as it includes a site which is generated by exposure and becomes an acid anion, but generates a sulfonate anion, a carbanion, a carboxylate anion, an imide anion, and a sulfonylmethide anion. Preferred groups are preferred.
Especially, as A < ^- >, group represented by the following formula (I-21)-(I-24) is preferable.

［Ｚ^３、Ｚ^５はそれぞれ独立に単結合、−Ｃ（＝Ｏ）−又は−ＳＯ_２−であり；Ｚ^４、Ｚ^６及びＺ^７はそれぞれ独立に−Ｃ（＝Ｏ）−又は−ＳＯ_２−である。Ｒ^６１、Ｒ^６２及びＲ^６３はそれぞれ独立にフッ素原子を有していてもよい炭化水素基である。Ｒ^６４は炭化水素基である。］

[Z ³ and Z ⁵ are each independently a single bond, —C (═O) — or —SO ₂ —; Z ⁴ , Z ⁶ and Z ⁷ are each independently —C (═O) — or —SO 2. _2- . R ⁶¹ , R ⁶² and R ⁶³ are each independently a hydrocarbon group which may have a fluorine atom. R ⁶⁴ is a hydrocarbon group. ]

In formula (I-22), R ⁶¹ represents a hydrocarbon group which may have a fluorine atom. Examples of the hydrocarbon group for R ⁶¹ include a linear or branched alkyl group, a monovalent alicyclic hydrocarbon group, an aryl group, and an aralkyl group.
The linear or branched alkyl group for R ⁶¹ preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, It may be linear or branched. Specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group and the like are preferable.
The monovalent alicyclic hydrocarbon group in R ⁶¹ is preferably those having 3 to 20 carbon atoms, more preferably those having 3 to 12 carbon atoms, and may be polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group in which one or more hydrogen atoms have been removed from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclobutane, cyclopentane, and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms. Adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.
The aryl group in R ⁶¹ is preferably those having 6 to 18 carbon atoms, more preferably those having 6 to 10 carbon atoms, and particularly preferably a phenyl group.
Aralkyl group in R ⁶¹ include those in which the "aryl group for R ^61" alkylene group and the above C1-8 bonded are preferred examples. More preferred is an aralkyl group in which an alkylene group having 1 to 6 carbon atoms and the above “aryl group in R ⁶¹ ” are bonded, and an aralkyl group in which an alkylene group having 1 to 4 carbon atoms and the above “aryl group in R ⁶¹ ” are bonded. Is particularly preferred.
In the hydrocarbon group for R ⁶¹ , part or all of the hydrogen atoms of the hydrocarbon group are preferably substituted with fluorine atoms, and 30 to 100% of the hydrogen atoms of the hydrocarbon group are substituted with fluorine atoms. More preferably. Especially, it is especially preferable that it is the perfluoroalkyl group by which all the hydrogen atoms of the alkyl group mentioned above were substituted by the fluorine atom.

In formula (I-23), R ⁶² and R ⁶³ are each independently a hydrocarbon group optionally having a fluorine atom, and the hydrocarbon group optionally having a fluorine atom in R ⁶¹ The same thing is mentioned.
In the formula (I-24), R ⁶⁴ is a hydrocarbon group, and is a linear or branched alkyl group, monovalent alicyclic hydrocarbon group, aryl group, and the like mentioned in the description of R ⁶¹ . Aralkyl groups and the like are preferable.

In formula (a6a-1), M ^{m +} is an organic cation, and m is an integer of 1 to 3.
The organic cation of M ^{m +} is not particularly limited. For example, conventionally known organic cations such as a photodegradable base used for a quencher of a resist composition and an onium acid generator of a resist composition are known. Cations can be used. As such an organic cation, for example, a cation represented by the following general formula (c-1) or (c-2) can be preferably used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基、アルキル基またはアルケニル基を表し；式（ｃ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２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; R ¹ ″ to R ³ ″ in formula (c-1); Any two of them may be bonded to each other to form a ring together with the sulfur atom in the formula. ]

In the formula (c-1), the aryl group, alkyl group, and alkenyl group of R ¹ ″ to R ³ ″ may have the substituents mentioned in R ^{4 to} R ⁵ above. It is the same as the alkyl group which may have alkenyl and the alkenyl group which may have a substituent.
In Formula (c-1), as R ¹ ″ to R ³ ″ each independently an aryl group, an alkyl group or an alkenyl group which may have a substituent, specific examples include Examples include cations represented by formulas (ca-1-1) to (ca-1-45).

［式中、ｇ１、ｇ２、ｇ３は繰返し数を示し、ｇ１は１〜５の整数であり、ｇ２は０〜２０の整数であり、ｇ３は０〜２０の整数である。］

[Wherein, g1, g2, and g3 represent the number of repetitions, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

Any two of R ¹ ″ to R ³ ″ in formula (c-1) may be bonded to each other to form a ring together with the sulfur atom in the formula. In this case, the ring may be saturated or unsaturated. The ring may be monocyclic or polycyclic. For example, when any one or both of R ¹ ″ to R ³ ″ form a ring is a cyclic group (a cyclic alkyl group or an aryl group), when they are bonded, a polycyclic ring ( Fused ring) is formed.
As the ring to be formed, one ring containing a sulfur atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring, particularly a 5- to 7-membered ring, including the sulfur atom. preferable.
The ring may have a hetero atom other than the sulfur atom to which R ¹ ″ to R ³ ″ are bonded as an atom constituting the ring skeleton. Examples of the hetero atom include a sulfur atom, an oxygen atom, and a nitrogen atom.
Specific examples of the ring formed include, for example, thiophene ring, thiazole ring, benzothiophene ring, thianthrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, thioxanthone ring, thianthrene ring, phenoxathiin ring, tetrahydro A thiophenium ring, a tetrahydrothiopyranium ring, etc. are mentioned.
In Formula (c-1), as a preferable specific example 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, for example, the following formula Examples thereof include cation moieties represented by (ca-12) to (ca-15).

［式中、Ｑ^４は単結合、メチレン基、硫黄原子、酸素原子、窒素原子、カルボニル基、−ＳＯ−、−ＳＯ_２−、−ＳＯ_３−、−ＣＯＯ−、−ＣＯＮＨ−または−Ｎ（Ｒ_Ｎ）−（該Ｒ_Ｎは炭素数１〜５のアルキル基である。）であり；Ｒ^８１〜Ｒ^８６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein Q ⁴ represents a single bond, a methylene group, a sulfur atom, an oxygen atom, a nitrogen atom, a carbonyl group, —SO—, —SO ₂ —, —SO ₃ —, —COO—, —CONH— or —N ( R _N ) — (wherein R _N is an alkyl group having 1 to 5 carbon atoms); R ^{81 to} R ⁸⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl. N _{1 to} n ₅ are each independently an integer of 0 to 3, and n ₆ is an integer of 0 to 2. ]

［式中、ｕは１〜３の整数であり、Ｒ^９は、置換基を有していてもよいフェニル基、ナフチル基またはアルキル基であり、Ｒ^１０は、置換基を有していてもよいフェニル基、ナフチル基、アルキル基、アルコキシ基または水酸基であり、Ｒ^４’は置換基を有していてもよいアルキレン基である。］

[Wherein, u is an integer of 1 to 3, R ⁹ is a phenyl group, a naphthyl group or an alkyl group which may have a substituent, and R ¹⁰ may have a substituent. A good phenyl group, naphthyl group, alkyl group, alkoxy group or hydroxyl group, and R ⁴ ′ is an alkylene group which may have a substituent. ]

In formulas (ca-12) to (ca-13), the alkyl group represented by R ^{81 to} R ⁸⁶ is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a linear or branched alkyl group, A methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{81 to} R ⁸⁶ are integers of 2 or more, the plurality of R ^{81 to} R ⁸⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.
Preferable examples of the cation represented by the formula (ca-12) or (ca-13) include those shown below.

In formulas (ca-14) to (ca-15), u is an integer of 1 to 3, and 1 or 2 is most preferable.
R ⁹ is a phenyl group, a naphthyl group or an alkyl group which may have a substituent.
Examples of the substituent that the phenyl group or naphthyl group in R ⁹ may have include the same groups as those described above as the substituent for the substituted arylene group in R ³ .
Examples of the alkyl group that may have a substituent in R ⁹ include the same alkyl groups that may have a substituent in R ^{4 to} R ⁵ .
R ¹⁰ is an optionally substituted phenyl group, naphthyl group, alkyl group, alkoxy group or hydroxyl group.
Examples of the substituent that the phenyl group or naphthyl group in R ¹⁰ may have include the same groups as those described as the substituent that the phenyl group or naphthyl group in R ⁹ may have.
Examples of the alkyl group which may have a substituent in R ^{10 and} the alkyl group in the alkoxy group include the same alkyl groups as in R ¹ ″ to R ³ ″.
The alkylene group for R ⁴ ′ is preferably a linear or branched alkylene group. 1-12 are preferable, as for carbon number of this alkylene group, 1-5 are more preferable, 1-3 are more preferable, and 1 or 2 is especially preferable.
Examples of the substituent that the alkylene group for R ⁴ ′ may have include the same groups as those described above for the substituent for the substituted arylene group for R ³ .
Preferable examples of the cation represented by the formula (ca-14) or (ca-15) include those shown below.

In formula (ca-14-1), R ^d is a substituent. Examples of the substituent include the same substituents as those described above as the substituent which the phenyl group or naphthyl group of R ⁹ may have.

The aryl group, alkyl group or alkenyl group that may have a substituent in R ⁵ ″ to R ⁶ ″ in formula (c-2) has a substituent in R ¹ ″ to R ³ ″. Examples of the aryl group, alkyl group or alkenyl group which may be used are the same.
Preferred specific examples in the formula (c-2) include diphenyliodonium, bis (4-tert-butylphenyl) iodonium, and the like.

The monomer having a group represented by the formula (a6a-1) is preferably a compound having an ethylenic double bond. Examples of the compound having an ethylenic double bond are the same as those described above, and in the monomers listed as "the group represented by the formula (a6c-1) and the monomer having an ethylenic double bond", the compound represented by the formula (a6c-1 ) Is a monomer substituted with a group represented by the formula (a6a-1).
Especially, the monomer by which the hydrogen atom of the carboxy group terminal of (alpha substituted) acrylic acid was substituted by the group represented by the said Formula (a6a-1) is especially preferable. A specific example is shown below. In the following formulas, R ^α is a hydrogen atom, a methyl group or a trifluoromethyl group, and M ^{m +} is the same as described above.

The component (A1) is obtained by polymerizing a monomer for deriving each structural unit by known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. be able to.
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

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, most preferably 2500 to 20000. 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.
Further, the dispersity (Mw / Mn) of the component (A1) is not particularly limited, and is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and 1.2 to 2 .5 is most preferred.
In addition, Mn shows a number average molecular weight.

In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the component (A) is 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, effects such as lithography characteristics are improved.

[(A2) component]
The resist composition may contain, as the component (A), a base material component (hereinafter referred to as the component (A2)) that does not correspond to the component (A1) and whose polarity is increased by the action of an acid.
The component (A2) is not particularly limited, and is conventionally known as a substrate component for a chemically amplified resist composition (for example, for ArF excimer laser, for KrF excimer laser (preferably ArF excimer laser). Base resin) and the like may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes a resin having the structural unit (a1) as an essential structural unit and optionally further including the structural units (a2) to (a4).
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

<Optional component>
[Acid generator component; (B) component]
The alkali development positive resist composition used in the pattern forming method of the present invention further contains an acid generator component (B) that generates an acid upon exposure, in addition to the component (A) or the component (A ′). It may be.
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 acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

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

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

Wherein ^{(b-1), R 1} "~R 3" is the same as ^R 1 ^{"~R 3"} in the general formula (c-1). Among them, since the further improved lithography properties and resist pattern ^shape, of R 1 "to R ^3", it is preferable that at least one is an aryl ^group, among the R 1 "~R ^3", 2 one The above is more preferably an aryl group, and it is particularly preferable that all of R ¹ ″ to R ³ ″ are aryl groups.
In formula (b-2), R ⁵ ″ to R ⁶ ″ are the same as R ⁵ ″ to R ⁶ ″ in general formula (c-2). Among them, since the lithography properties and resist pattern shape is further ^improved, among R 5 "~R ^6", it is preferable that at least one is an aryl ^group, any aryl group R 5 "~R ^6" It is more preferable that

In the formulas (b-1) to (b-2), Z ⁻ is the same as V ⁻ in the formula (a6c-1).

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
Moreover, the anion part of these onium salts is replaced with the anion represented by any one of the formulas (b1) to (b9) or the anion represented by the formula (b-3) or (b-4). An onium salt-based acid generator can also be used. In this case, the cation part is the same as the cation part in the formula (b-1) or (b-2).

  Moreover, as an onium salt-based acid generator, a sulfonium salt having a cation represented by the above formulas (ca-12) to (ca-15) in the cation portion can also be used.

As the oxime sulfonate acid generator, an oxime sulfonate acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014], [Chem. 18] to [Chem. 19]), International Publication An oxime sulfonate-based acid generator disclosed in the pamphlet of No. 04/074242 (Examples 1 to 40 on pages 65 to 86) can be preferably used.
As the diazomethane acid generator, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can 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.
0.5-60 mass parts is preferable with respect to 100 mass parts of (A) component or (A ') component, and, as for content of (B) component in the pattern formation method of this invention, 1-50 mass parts is more preferable. 1 to 40 parts by mass is more preferable. (B) By making content of a component into the said range, formation of a guide pattern is fully performed. Moreover, when each component of a resist composition is melt | dissolved in the organic solvent, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Basic compound component; (D) component>
The component (D) is a basic compound component, and acts as an acid diffusion control agent, that is, a quencher that traps acid generated from the component (B) by exposure. In the present invention, the “basic compound” refers to a compound that is relatively basic with respect to the component (B). (D) component in this invention contains the basic compound component (D1) (henceforth "(D1) component") which has a fluorine atom.

[(D1) component]
The component (D1) in the present invention is not particularly limited as long as it is relatively basic with respect to the component (B), but includes a compound composed of a cation part and an anion part. Preferably, it contains a photoreactive quencher, more preferably a compound (d1) represented by the following general formula (d1) (hereinafter referred to as component (d1)), a compound represented by the following general formula (d2) ( d2) containing at least one compound selected from the group consisting of (hereinafter referred to as component (d2)) and compound (d3) represented by the following general formula (d3) (hereinafter referred to as component (d3)). Is more preferable. The “photoreactive quencher” does not act as a quencher in the exposed part, but acts as a quencher in the unexposed part.

［式中、Ｒｄ^１〜Ｒｄ^４は置換基を有していてもよい炭化水素基である。ただし、式（ｄ２）において、Ｓ原子に隣接する炭素原子にはフッ素原子は結合していないものとする。
Ｙｄ^５はアルキレン基又はアリーレン基であり、Ｍ^ｍ＋はそれぞれ独立にｍ価の有機カチオンである。］

^Wherein, Rd 1 ^{~Rd 4} is a hydrocarbon group which may have a substituent. However, in the formula (d2), it is assumed that no fluorine atom is bonded to the carbon atom adjacent to the S atom.
Yd ⁵ is an alkylene group or an arylene group, and M ^{m +} is each independently an m-valent organic cation. ]

[(D1) component]
In the anion partial formula (d1), Rd ¹ is a hydrocarbon group that may have a substituent.
The hydrocarbon group which may have a substituent of Rd ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the aliphatic hydrocarbon of X ^{3 in} the component (B) Group and the same aromatic hydrocarbon group.
Among them, the hydrocarbon group which may have a substituent of Rd ¹ is an aromatic hydrocarbon group which may have a substituent, or an aliphatic cyclic group which may have a substituent. A phenyl group or naphthyl group which may have a substituent; one or more hydrogen atoms are removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. More preferably, it is a group.

Further, the hydrocarbon group which may have a substituent of Rd ¹ is preferably a linear, branched, or alicyclic alkyl group, or a fluorinated alkyl group.
The linear, branched or alicyclic alkyl group of Rd ¹ preferably has 1 to 10 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, Linear alkyl group such as hexyl group, heptyl group, octyl group, nonyl group, decyl group, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group A branched alkyl group such as 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, norbornyl group And alicyclic alkyl groups such as an adamantyl group.

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

  Preferred specific examples of the anion moiety of the component (d1) are shown below.

-Cation part In Formula (d1), Mm ⁺ is an organic cation.
Although it does not specifically limit as an organic cation of Mm ⁺ , For example, the cation part represented by the said Formula (c-1) and (c-2) is mentioned.
As the component (d1), one type may be used alone, or two or more types may be used in combination.

[(D2) component]
Anion formula (d2), Rd ² is a hydrocarbon group of 1 to 30 carbon atoms which may have a substituent.
The hydrocarbon group having 1 to 30 carbon atoms which may have a substituent of Rd ² may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and X in the component (B) ^{And the same as} the aliphatic hydrocarbon group and aromatic hydrocarbon group.
Among them, the hydrocarbon group which may have a substituent of Rd ² is preferably an aliphatic cyclic group which may have a substituent, such as adamantane, norbornane, isobornane, tricyclodecane, It is more preferably a group obtained by removing one or more hydrogen atoms from tetracyclododecane, camphor or the like (which may have a substituent).
The hydrocarbon group for Rd ² may have a substituent, and examples of the substituent include the same as X ³ in the component (B). However, in Rd ² , the carbon adjacent to the S atom in SO ₃ ^— is not fluorine-substituted. Since SO ₃ ^— and a fluorine atom are not adjacent to each other, the anion of the component (d2) becomes an appropriate weak acid anion, and the quenching ability of the component (D) is improved.
Preferred specific examples of the anion moiety of the component (d2) are shown below.

· Cation In formula (d2), ^{M m +} is the same as ^{M m +} in the formula (d1) in.
As the component (d2), one type may be used alone, or two or more types may be used in combination.

[(D3) component]
Anion formula (d3), Rd ⁴ is an organic group.
The organic group of Rd ⁴ is not particularly limited, but an alkyl group, an alkoxy group, —O—C (═O) —C (R ^C2 ) ═CH ₂ (R ^C2 is a hydrogen atom, and has 1 to 5 carbon atoms. Or an alkyl group having 1 to 5 carbon atoms), or —O—C (═O) —R ^C3 (R ^C3 is a hydrocarbon group).
The alkyl group of Rd ⁴ 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, an n-butyl group, an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A part of the hydrogen atoms of the alkyl group of Rd ⁴ may be substituted with a hydroxyl group, a cyano group, or the like.
The alkoxy group of Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms. Specific examples of the alkoxy group having 1 to 5 carbon atoms include methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n- Examples include butoxy group and tert-butoxy group. Of these, a methoxy group and an ethoxy group are most preferable.

When Rd ⁴ is —O—C (═O) —C (R ^C2 ) ═CH ₂ , R ^C2 is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. is there.
The alkyl group having 1 to 5 carbon atoms in R ^C2 is preferably a linear or branched alkyl group having 1 to 5 carbon atoms. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, n -Butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like can be mentioned.
The halogenated alkyl group in R ^C2 is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R ^C2 is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a fluorinated alkyl group having 1 to 3 carbon atoms, and is most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

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

Among them, as Rd ⁴ , —O—C (═O) —C (R ^C2 ′) ═CH ₂ (R ^C2 ′ is a hydrogen atom or a methyl group), or —O—C (═O ) -R ^C3 ′ (R ^C3 ′ is an aliphatic cyclic group).

In formula (d3), Yd ¹ represents a linear, branched or cyclic alkylene group or an arylene group.
Yd ¹ linear, the branched or cyclic alkylene group or arylene group, among the divalent linking group for Q ¹ in the formula (a6c-1), "linear or branched Examples thereof include the same as “aliphatic hydrocarbon group”, “cyclic aliphatic hydrocarbon group”, and “aromatic hydrocarbon group”.
Among these, Yd ¹ is preferably an alkylene group, more preferably a linear or branched alkylene group, and even more preferably a methylene group or an ethylene group.

In the formula (d3), Rd ³ is a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom of Rd ³ is preferably a fluorinated alkyl group, and more preferably the same as the fluorinated alkyl group of Rd ¹ .
Preferred specific examples of the anion moiety of the component (d3) are shown below.

· Cation In formula (d3), ^{M m +} is the same as ^{M m +} in the formula (d1) in.
As the component (d3), one type may be used alone, or two or more types may be used in combination.

The component (D1) may contain only one of the above components (d1) to (d3), or may contain two or more in combination.
The total content of the components (d1) to (d3) is preferably 0.5 to 10.0 parts by mass with respect to 100 parts by mass of the component (A), and 0.5 to 8.0 parts by mass. It is more preferable that it is 1.0 to 8.0 parts by mass. When it is at least the lower limit of the above range, particularly good lithography properties and resist pattern shape can be obtained. When the amount is not more than the upper limit of the above range, the sensitivity can be maintained satisfactorily and the throughput is excellent.

(Production method of component (D1))
The production method of the component (d1) and the component (d2) in the present invention is not particularly limited and can be produced by a known method.
Further, the production method of the component (d3) is not particularly limited. For example, when Rd ⁴ in the formula (d3) is a group having an oxygen atom at the terminal bonded to Yd ¹ , the following general formula By reacting the compound (i-1) represented by the formula (i-1) with the compound (i-2) represented by the following general formula (i-2), the following general formula (i-3) The compound (i-3) represented by the formula (d3) is reacted with the compound (i-3) and Z ⁻ M ⁺ (i-4) having the desired cation M ^+. The compound (d3) represented by these is manufactured.

［式中、Ｒ^２、Ｙ^３、Ｒｆ、Ｍ^＋は、それぞれ、前記一般式（ｄ３）中のＲｄ^４、Ｙｄ^１、Ｒｄ^３、Ｍ^ｍ＋と同じである（ｍ＝１）。Ｒ^２ａはＲ^２から末端の酸素原子を除いた基であり、Ｚ⁻は対アニオンである。］

[Wherein, R ² , Y ³ , Rf, and M ⁺ are the same as Rd ⁴ , Yd ¹ , Rd ³ , and M ^{m + in the} general formula (d3), respectively (m = 1). R ^2a is a group obtained by removing a terminal oxygen atom from R ² , and Z ⁻ is a counter anion. ]

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

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

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

Next, the obtained compound (i-3) and the compound (i-4) are reacted to obtain the compound (d1-3).
In formula (i-4), M ⁺ is the same as described above, and Z ⁻ is a counter anion.
The method of reacting compound (i-3) and compound (i-4) to obtain compound (d1-3) is not particularly limited. For example, the compound is obtained in the presence of a suitable alkali metal hydroxide. It can be carried out by dissolving (i-3) in a suitable organic solvent and water, adding compound (i-4) and reacting with stirring.

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

The reaction time in the above reaction varies depending on the reactivity between the compound (i-3) and the compound (i-4), the reaction temperature, etc., but is usually preferably 1 to 80 hours, more preferably 3 to 60 hours. .
The reaction temperature in the above reaction is preferably 20 ° C to 200 ° C, more preferably about 20 ° C to 150 ° C.
After completion of the reaction, the compound (d3) in the reaction solution may be isolated and purified. For isolation and purification, conventionally known methods can be used. For example, concentration, solvent extraction, distillation, crystallization, recrystallization, chromatography, etc. can be used alone or in combination of two or more thereof. it can.

The structure of the compound (d3) obtained as described above has the following structure: ¹ H-nuclear magnetic resonance (NMR) spectrum method, ¹³ C-NMR spectrum method, ¹⁹ F-NMR spectrum method, infrared absorption (IR) spectrum method, mass It can be confirmed by a general organic analysis method such as analysis (MS) method, elemental analysis method or X-ray crystal diffraction method.

  The content of the component (D1) is preferably 0.5 to 10.0 parts by mass and more preferably 0.5 to 8.0 parts by mass with respect to 100 parts by mass of the component (A). 1.0 to 8.0 parts by mass is even more preferable. When it is at least the lower limit of the above range, particularly good lithography properties and resist pattern shape can be obtained. When the amount is not more than the upper limit of the above range, the sensitivity can be maintained satisfactorily and the throughput is excellent.

[(D2) component]
(D) component may contain the other basic compound component (henceforth (D2) component) which does not correspond to the said (D1) component.
The component (D2) is particularly limited as long as it is a compound that is relatively basic with respect to the component (B), acts as an acid diffusion controller, and does not fall under the component (D1). It may be used arbitrarily from known ones. Of these, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, Li isopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

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

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

As the component (D2), an aromatic amine may be used.
Aromatic amines include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. And carbonylpyrrolidine.

(D2) A component may be used independently and may be used in combination of 2 or more type.
(D2) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

(D) A component may be used individually by 1 type and may be used in combination of 2 or more type.
When the alkali development positive resist composition used in the pattern forming method of the present invention contains the component (D), the component (D) is 0.1 to 15 parts by mass with respect to 100 parts by mass of the component (A). It is preferable that it is 0.3 to 12 parts by mass, and more preferably 0.5 to 12 parts by mass. When it is at least the lower limit of the above range, lithography properties such as roughness are further improved when a resist composition is used. Further, a better resist pattern shape can be obtained. When the amount is not more than the upper limit of the above range, the sensitivity can be maintained satisfactorily and the throughput is excellent.

<Optional component>
[(E) component]
The alkali development positive resist composition used in the pattern forming method of the present invention includes an organic carboxylic acid as an optional component for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, stability with time, and the like. At least one compound (E) selected from the group consisting of phosphorus oxoacids and derivatives thereof (hereinafter referred to as component (E)) can be contained.
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 phosphinic acid derivatives include phosphinic acid esters and phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
(E) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

[(S) component]
The resist composition used in the pattern forming method of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol Polyhydric alcohols such as: ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, etc., compounds having an ester bond, monohydric ethers of the polyhydric alcohols or compounds having an ester bond , Monoalkyl ethers such as monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having an ether bond [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, and lactic acid Esters such as methyl, 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, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. An aromatic organic solvent, dimethyl sulfoxide (DMSO), etc. can be mentioned.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Of these, PGMEA, PGME, γ-butyrolactone, 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.
More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA: EL or cyclohexanone 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.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
(S) The usage-amount of a component is not specifically limited, It is a density | concentration which can be apply | coated to a board | substrate etc., and is suitably set according to a coating film thickness. Generally, it is used so that the solid content concentration of the resist composition is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

<< Resist composition suitable for solvent development process >>
In the pattern forming method of the present invention, a known negative resist composition can be applied as a resist composition for forming a guide pattern. Below, a suitable negative resist composition is illustrated.

  The negative resist preferably contains a base material component whose polarity is increased by the action of an acid and whose solubility in a developer containing an organic solvent is reduced, and an acid generator component that generates an acid upon exposure. In such a negative developing resist composition, when irradiated (exposed) with radiation, an acid is generated from the acid generator component, and the solubility of the base component in an organic solvent is reduced by the action of the acid. Therefore, in the formation of the guide pattern, when the resist film obtained using the resist composition is selectively exposed, the solubility of the exposed part of the resist film in the organic developer containing the organic solvent is determined. However, since the solubility of the unexposed area in the organic developer does not change, negative development using the organic developer removes the unexposed area and forms a guide pattern. The

  The solvent-developed negative resist composition used in the pattern forming method of the present invention generates a base component (hereinafter referred to as component (A)) whose solubility in an organic solvent is reduced by the action of an acid and an acid upon exposure. It is preferable to contain an acid generator component (hereinafter referred to as component (B)).

As the component (A) in the negative resist composition, those similar to the component (A) of the alkali development positive resist composition described above can be applied. However, in the solvent development negative resist, it is preferable that the component (A) does not have a 3 to 7-membered ether-containing cyclic group. Since the component (A) does not have a 3- to 7-membered ether-containing cyclic group, heat treatment for imparting heat resistance to the resist pattern becomes unnecessary, and phase separation in the phase separation step is performed by low-temperature heat treatment. be able to.
Here, the “ether-containing cyclic group” means a cyclic group containing a structure (cyclic ether) in which carbon of a cyclic hydrocarbon is substituted with oxygen.

As the component (B) in the negative resist composition, the same component as the component (B) in the alkali development positive resist composition described above can be applied.
The negative resist composition can be produced by dissolving each component in an organic solvent. As the organic solvent, those similar to the component (S) of the alkali development positive resist composition described above can be applied.
Further, the negative resist composition may contain the component (D) or the component (E) of the alkali development positive resist composition described above as an optional component.

In addition, the solvent-developed negative resist composition used in the pattern forming method of the present invention is a base material component (the above-mentioned (A ′) component) that generates an acid upon exposure and has reduced solubility in an organic solvent by the action of the acid. ) May be contained. The substrate component (A ′) preferably contains a resin component (component (A1 ′) described above) having a structural unit (component (a6) described above) that generates an acid upon exposure.
Furthermore, the solvent development negative resist composition used in the pattern forming method of the present invention may contain the component (A ′) and the component (B).
The solvent-developed negative resist composition may be a resist composition containing both the component (A) and the component (A ′). Specifically, a resist composition containing both the structural unit (a1) and the structural unit (a6), or the structural units (a1) and (a6) and the structural units (a2), (a3), (a4), Examples thereof include resist compositions containing any one or more selected from the components (a5) and (B).

  In the pattern forming method using the block copolymer-containing composition of the present invention, the alkali development positive resist composition constituting the guide pattern is composed of the structural unit represented by the general formula (a1-1), Of these, any one or more structural units, preferably two or more structural units among the structural units having a monocyclic protecting group, the structural unit (a5), and the structural units having a polycyclic protecting group such as an adamantane group. It is preferable to include a polymer containing as a monomer. The water contact angle of the side surface of the concave portion of the guide pattern having these structural units can be easily made larger than the water contact angle of a known antireflection film that may constitute the bottom surface of the concave portion.

  In the pattern formation method using the block copolymer-containing composition of the present invention, the solvent-developed negative resist composition constituting the guide pattern is a structural unit represented by the general formula (a1-1), Among these, it is preferable to include a polymer containing any one or more constituent units as monomers among constituent units having a monocyclic protecting group and constituent units having a polycyclic protecting group such as an adamantane group. The water contact angle of the side surface of the concave portion of the guide pattern having these structural units can be easily made larger than the water contact angle of a known antireflection film that may constitute the bottom surface of the concave portion.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

<Preparation Example 1>
A resist composition for forming a guide pattern was prepared.
[Solvent development negative resist composition]
100 parts by mass of a polymer represented by the following formula (a) -1 (Mw: 7100, polydispersity index: PDI: 1.65), photoacid generation represented by the following formula (b) -1 10 parts by weight of an agent (manufactured by Wako Pure Chemical Industries, Ltd.), 1.0 part by weight of tri-n-pentylamine, 1.5 parts by weight of salicylic acid, and 2500 parts by weight of PGMEA are dissolved and dissolved. A composition solution was prepared. The ratio (mol%) of each structural unit is l: m: n = 40: 40: 20.

<Preparation Example 2>
[Alkali development positive resist composition]
100 parts by mass of a polymer represented by the following formula (a) -2 (Mw: 6900, polydispersity index: PDI): 1.61), photoacid generation represented by the formula (b) -1 10 parts by weight of an agent (manufactured by Wako Pure Chemical Industries, Ltd.), 1.0 part by weight of tri-n-pentylamine, 1.5 parts by weight of salicylic acid, and 2500 parts by weight of PGMEA are dissolved and dissolved. A composition solution was prepared. The ratio (mol%) of each structural unit is l: m: n: o: p = 35: 24: 16: 13: 12.

<Preparation Example 3>
[Alkali development positive resist composition]
100 parts by mass of a polymer represented by the following formula (a) -3 (Mw: 7200, polydispersity index (PDI): 1.71), photoacid generation represented by the formula (b) -1 10 parts by weight of an agent (manufactured by Wako Pure Chemical Industries, Ltd.), 1.0 part by weight of tri-n-pentylamine, 1.5 parts by weight of salicylic acid, and 2500 parts by weight of PGMEA are dissolved and dissolved. A composition solution was prepared. The ratio (mol%) of each structural unit is l: m: n = 40: 40: 20.

<Example 1>
First, an organic antireflection film composition “ARC-29A” (trade name, manufactured by Brewer Science Co., Ltd.) was applied on an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds. By drying, an organic antireflection film having a film thickness of 89 nm was formed.
Next, the resist composition prepared in Preparation Example 1 is applied onto an organic antireflection film using a spinner, and prebaked (PAB) is performed on a hot plate at 105 ° C. for 60 seconds. Then, a resist film having a film thickness of 100 nm was formed by drying.

  Next, ArF exposure apparatus S308B (manufactured by Nikon Corporation; NA (numerical aperture) = 0.92, Crosssole (0.62 to 0.77) with POLANO), Dose = 85.6 mJ is applied to the resist film. Excimer laser (193 nm) was selectively irradiated through the mask pattern. Then, post-exposure heating (PEB) treatment was performed at 95 ° C. for 60 seconds, followed by development with butyl acetate for 16 seconds, followed by shake-off drying. Subsequently, a post-bake treatment was performed at 100 ° C. for 1 minute and then at 150 ° C. for 1 minute. As a result, a support in which circular hole patterns (guide holes) having a diameter of 90 nm were formed at a pitch of 155 nm was obtained.

Next, a block copolymer-containing composition obtained by mixing and dissolving the components shown in Table 1 is spin-coated on the support so that the thickness from the bottom surface of the hole pattern is 17.5 nm (number of rotations: (1500 rpm, 60 seconds), and a pre-baking (PAB) treatment was performed at 110 ° C. for 60 seconds to form a layer containing the PS-PMMA block copolymer. Then, the said board | substrate was heat-processed for 60 second at 150 degreeC under nitrogen stream, and the phase-separation structure was formed.
Thereafter, using TCA-3822 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), the substrate was subjected to oxygen plasma treatment (200 sccm, 40 Pa, 200 W, 40 ° C., 20 seconds) to selectively select a phase composed of PMMA. Removed.

In Table 1, the components (Ap) to (C ″) are the following compounds, respectively, and the numerical values in [] in the table are blending amounts (parts by mass).
(Ap) -1: PS-PMMA block copolymer 1 (PS Mw (mass average molecular weight): 60000, PMMA Mw: 27000, PS / PMMA = 70/30, PDI: 1.02)
(B ″)-1: phenyldiglycol (C ″)-1: ethylcyclohexane / butyl acetate = 50/50

The surface of the obtained substrate was observed using a scanning electron microscope SU8000 (manufactured by Hitachi High-Technologies Corporation).
A circle with one reduced circular hole formed per guide hole that was originally formed by phase separation, and two or more holes per guide hole that were originally formed by phase separation. The evaluation was performed with x being formed or having no holes formed by phase separation. The results are also shown in Table 1.
Moreover, the ratio of the guide hole in which the favorable circular hole ((circle)) was formed among several guide holes which comprise a hole pattern was calculated | required as a hole opening rate. The results are also shown in Table 1.

<Example 2>
A support was prepared in the same manner as in Example 1 using the resist composition of Preparation Example 2 instead of the resist composition of Preparation Example 1. As a result, a resist film having a thickness of 100 nm was formed.

Next, ArF exposure apparatus S308B (manufactured by Nikon Corporation; NA (numerical aperture) = 0.92, Crosssole (0.62 to 0.77) with POLANO), Dose = 85.6 mJ is applied to the resist film. Excimer laser (193 nm) was selectively irradiated through the mask pattern. Then, post-exposure heating (PEB) treatment was performed at 95 ° C. for 60 seconds, and further development was performed with NMD-3 (Tokyo Ohka) for 16 seconds, followed by shake-off drying. Subsequently, a post-bake treatment was performed at 100 ° C. for 1 minute and then at 150 ° C. for 1 minute. As a result, a support in which circular hole patterns (guide holes) having a diameter of 90 nm were formed at a pitch of 155 nm was obtained.
Next, a layer containing a block copolymer is formed in the concave portion constituted by the guide pattern on the obtained support by the same method as in Example 1, and further, the phase comprising PMMA by the same method as in Example 1. Was selectively removed.
The surface of the obtained substrate was evaluated in the same manner as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
The same conditions as in Example 2 were used except that the resist composition of Preparation Example 3 was changed to conditions of PAB treatment at 115 ° C. for 60 seconds, exposure of Dose 35.6 mJ, and PEB treatment at 115 ° C. for 60 seconds. An attempt was made to form a hole pattern. As shown in Table 1, good holes could not be formed.

<Measurement of water contact angle>
The water contact angle (θ _A ) on the side surface of the recess of the guide pattern made of each resist composition and the water contact angle (θ _B ) on the bottom surface were measured as follows.
theta _A, as described above, the resist film in the same state as the side surface produced separately, using a value obtained by measuring the water contact angle of the resist film with theta / 2 method.
θ _B was determined by measuring the water contact angle of the surface of the antireflection film formed on the surface of the silicon wafer. This water contact angle is measured according to JIS R 325 (1999) using Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.) and measuring 2.0 μl of ultrapure water after 200 ms has elapsed after dropping, and using a 5-point measurement average The contact angle was determined. At this time, software: KYOWA interFAce Measurement and Analysis System FAMAS was used.
Table 1 shows the water contact angle values obtained.

As a result, the absolute value of the difference (θ _A −θ _B ) in water contact angle between the side surface and the bottom surface constituting the concave portion of the guide pattern is 5 degrees or more. Since the layer containing the block copolymer could be sufficiently phase-separated by heat treatment at a relatively low temperature, one final target pattern reflecting the shape of the guide hole could be formed. On the other hand, in Comparative Example 1 where the absolute value was less than 5 degrees, the phase separation of the layer containing the block copolymer was insufficient, and the final target pattern could not be obtained.

11 ... substrate, 12 ... antireflection film 14 ... resist pattern, a layer containing 13 ... block copolymer, a phase consisting of 13a ... _{P B} block, phase consisting 13b ... _{P A} block

Claims (2)

It has a guide pattern formed on the surface by a resist composition having a structural unit (a1) containing an acid-decomposable group that generates an acid upon exposure and increases in polarity by the action of the acid, For a support that does not have a neutralization film on the bottom,
A block copolymer layer forming step of forming a block copolymer-containing layer using a composition comprising a block copolymer in which a plurality of types of blocks are bonded and an organic solvent so as to cover the bottom surface of the concave portion of the guide pattern;
After the block copolymer layer forming step, a phase separation step for phase separation of the layer containing the block copolymer;
After the phase separation step, a step of selectively removing a phase composed of at least one block of a plurality of types of blocks constituting the block copolymer from the layer containing the block copolymer,
The guide pattern of the bottom and side surfaces constituting the concave portion of the state, and are the absolute value of 5 degrees or more of the difference between the water contact angle,
Said composition comprising the block copolymer and the organic solvent, further, the vapor pressure at 20 ° C. is not more than 0.05HPa, a pattern forming method and the freezing point is characterized that you containing compound is 25 ° C. or less .   The pattern formation method according to claim 1, wherein in the phase separation step, the block copolymer layer is phase-separated by performing a heat treatment at 100 to 180 ° C. for 10 to 600 seconds.

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