JP2010243671A - Resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist pattern forming method forming a minute multilayered resist pattern having a complicated three-dimensional structure such as a hollow structure by using a liquid resist such as a KrF resist or an ArF resist. <P>SOLUTION: The resist pattern forming method comprises a first process for forming a first resist film by using a first chemical amplification type resist composition and performing selective exposure on the first resist film, a second process for forming a second resist film by applying a second chemical amplification type resist composition onto the first resist film and performing selective exposure on the second resist film, and a process for developing the first resist film and the second resist film to form a multilayered resist pattern. The first chemical amplification type resist composition is a positive resist composition increasing its solubility to an alkali developer by exposure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resist pattern forming method using a chemically amplified resist composition. Specifically, the first film is formed and exposed using a first chemically amplified resist composition, and a second film is further formed thereon. The present invention relates to a resist pattern forming method for forming a multilayer resist pattern having a complicated three-dimensional structure such as a hollow structure by applying a chemically amplified resist composition and performing exposure and development.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film. A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the exposure light source is generally shortened in wavelength (increased energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but now mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. Further, studies have been made on electron beams having shorter wavelengths (higher energy) than these excimer lasers, EUV (extreme ultraviolet rays), X-rays, and the like.

  Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material that satisfies these requirements, a chemically amplified resist obtained by dissolving, in an organic solvent, a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator component that generates an acid upon exposure. Is used. For example, a positive chemically amplified resist is formed by dissolving a resin whose solubility in an alkali developer increases by the action of an acid as a base resin and an acid generator component in an organic solvent. When an acid is generated from the acid generator by exposure, the exposed portion becomes soluble in an alkali developer.

Up to now, as the base resin for chemically amplified resist, polyhydroxystyrene (PHS), which is highly transparent to KrF excimer laser (248 nm), and a resin whose hydroxyl group is protected with an acid dissociable, dissolution inhibiting group (PHS resin) Has been used. However, since the PHS resin has an aromatic ring such as a benzene ring, the transparency to light having a wavelength shorter than 248 nm, for example, 193 nm, is not sufficient. Therefore, a chemically amplified resist having a PHS-based resin as a base resin component has drawbacks such as low resolution in a process using 193 nm light, for example.
Therefore, as a resist base resin currently used in ArF excimer laser lithography and the like, since it has excellent transparency near 193 nm, a resin (acrylic resin) having a structural unit derived from (meth) acrylic ester is used. System resin) is mainly used (see, for example, Patent Document 1).

Further, as one of the recently proposed lithography techniques, there is a double patterning process in which a resist pattern is formed by performing patterning twice or more (see, for example, Non-Patent Documents 1 and 2).
In this double patterning process, for example, a first resist film is formed on a support, a plurality of resist patterns are formed by patterning the first resist film, and then a second resist material is formed thereon. By applying, forming a second resist film between the plurality of resist patterns, and patterning the second resist film, a resist pattern having higher resolution than a resist pattern formed by one patterning Can be formed.

  On the other hand, in recent years, formation of a multilayer resist pattern by a thick film lithography method and a plating method has attracted attention in a formation method of a microstructure or a micropart represented by a MEMS (Micro ElectroMechanical System). For example, in Patent Document 2, a layer of a negative photoresist composition is formed, and after heating, exposure, and if necessary, a process of heating as necessary is repeated twice or more, and then a negative photoresist layer is stacked. A technique is disclosed in which a multilayer resist pattern is formed by developing the layers simultaneously, and a plated product is formed by plating the multilayer resist pattern.

JP 2003-241385 A JP 2006-17969 A

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

In recent years, in a semiconductor device, multilayer structure wiring has become mainstream in order to cope with miniaturization and high integration. As for the wiring material, the application of Cu wiring having a lower electrical resistivity k than the conventional Al wiring is being studied. The dual damascene method is the mainstream because it is difficult to apply chemical etching in Cu wiring formation. In the dual damascene method, vias (wiring connection holes) and trenches (wiring grooves) are continuously formed in an insulating film, and Cu is embedded at the same time by electroplating (ECD). At this time, if a trench is formed after Cu is embedded after forming a via and Cu is embedded, it becomes difficult to control the Cu junction interface between the via and the trench as the wiring size decreases. Therefore, by forming a via and a trench simultaneously by forming a fine wiring pattern of a hollow structure having a T-shaped cross-sectional shape and the like, and by embedding Cu therein, Cu is embedded in both the via and the trench at once. It is expected that the problem of controlling the Cu bonding interface can be solved.
As a result of investigations by the present inventors, when forming a fine pattern having a hollow structure using a multilayer resist pattern forming method as described in Patent Document 2, a liquid resist is supported as a first resist on a substrate or the like. After coating on the body, heating, exposure, and heating as necessary, the second resist is laminated with a film-type resist that itself becomes a support, and heated, exposed, and developed to form a pattern. I found it necessary. However, in the case of forming a fine pattern, a KrF resist, an ArF resist, or the like is generally used. However, since a KrF resist or an ArF resist is mainly a liquid resist, it is applied to a method as described in Patent Document 2. It is difficult to do.
Further, as a result of investigations by the present inventors, even if both the first and second resists are liquid resists in Patent Document 2, the pattern size that can be formed by the method described in Patent Document 2 is several tens of times. It has been found that the micrometer order is the limit, and miniaturization to the order of tens to hundreds of nanometers is difficult.
On the other hand, in the double patterning process, although a high-resolution resist pattern can be formed on a plane, both the resist pattern made of the first resist material and the resist pattern made of the second resist material overlap, so that the resist pattern having a hollow structure Cannot be formed.

  The present invention has been made in view of the above circumstances, and uses a liquid resist such as a KrF resist or an ArF resist to form a fine multilayer resist pattern having a complicated three-dimensional structure such as a hollow structure. An object of the present invention is to provide a resist pattern forming method capable of forming

  In order to solve the above problems, the present invention employs the following configuration.

That is, the resist pattern forming method of the present invention includes a first step of forming a first resist film using the first chemically amplified resist composition, and selectively exposing the first resist film. ,
A second chemically amplified resist composition is applied onto the first resist film to form a second resist film, the second resist film is selectively exposed, and a post-exposure bake treatment is performed. The second step,
Developing the first resist film and the second resist film to form a multilayer resist pattern,
In the resist pattern forming method, the first chemically amplified resist composition is a positive resist composition whose solubility in an alkaline developer is increased by exposure.

In the present specification and claims, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Further, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups unless otherwise specified.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
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.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
The “structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

“(Meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position.
“(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
“(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.

  According to the resist pattern forming method of the present invention, a fine multilayer resist pattern having a complicated three-dimensional structure such as a hollow structure can be formed using a liquid resist such as a KrF resist or an ArF resist.

It is a schematic diagram which shows an example of the aspect of the resist pattern formation method of this invention. It is a photograph figure of the resist pattern formed in Example 1-2.

≪Pattern formation method≫
FIG. 1 is a schematic view showing an example of an embodiment of a resist pattern forming method of the present invention.
In the resist pattern forming method of the present invention, a first resist film is formed using the first chemically amplified resist composition [step (A)], and the first resist film is selectively exposed [ Step (B)], a post-exposure bake treatment if desired [Step (C)] a first step (hereinafter, steps (A) to (C) are collectively referred to as “film forming step (1)”); On the first resist film, a chemically amplified resist composition is applied to form a second resist film [Step (D)], and the second resist film is selectively exposed [Step (E )], A post-exposure bake treatment [step (F)] a second step (hereinafter, steps (D) to (F) are collectively referred to as “film formation step (2)”), and the first resist Developing the film and the second resist film to form a multilayer resist pattern [Step (G)] , And a called "patterning step").
Hereinafter, each step will be described in more detail.

[Film Formation Step (1)]
The method for forming the first resist film using the first chemically amplified resist composition is not particularly limited, and examples thereof include a method of applying the first chemically amplified resist composition to a support such as a substrate. .
The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC) and a lower layer film in a multilayer resist method. In particular, it is preferable to provide an organic film because a pattern with a high aspect ratio can be formed on a substrate, which is useful in manufacturing semiconductors.
Here, the multilayer resist method is a method in which at least one organic film (lower layer film) and at least one resist film are provided on a substrate, and the lower layer patterning is performed using the resist pattern formed on the upper resist film as a mask. It is said that a high aspect ratio pattern can be formed. In the multilayer resist method, basically, a method having a two-layer structure of an upper layer resist film and a lower layer film, and one or more intermediate layers (metal thin films, etc.) are provided between these resist film and lower layer film. It is divided into a method of providing a multilayer structure of three or more layers provided. According to the multilayer resist method, by securing a required thickness with the lower layer film, the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
The inorganic film can be formed, for example, by applying an inorganic antireflective film composition such as a silicon-based material on a substrate and baking it.
The organic film is formed by, for example, applying an organic film forming material in which a resin component or the like constituting the film is dissolved in an organic solvent to a substrate with a spinner or the like, preferably 200 to 300 ° C., preferably 30 to 300 seconds, More preferably, it can be formed by baking under heating conditions of 60 to 180 seconds.

The method for forming the first resist film by applying the first chemically amplified resist composition on the support is not particularly limited, and a conventionally known method can be used. In the present invention, it is necessary to use a positive resist composition described later as the first chemically amplified resist composition.
Specifically, for example, the first chemically amplified resist composition is applied onto a support by using a conventionally known method such as using a spinner, and prebaked (PAB) under a temperature condition of 80 to 150 ° C. ) Treatment (hereinafter referred to as “first PAB treatment”) for 40 to 120 seconds, preferably 60 to 90 seconds, and volatilizing the organic solvent, the first resist film can be formed.
The thickness of the first resist film is preferably 50 to 500 nm, more preferably 50 to 450 nm. By setting it within this range, there are effects such that a resist pattern can be formed with high resolution and sufficient resistance to etching can be obtained.

  Next, the first resist film is selectively exposed. Specifically, for example, the first resist film formed as described above is selectively exposed through a photomask, and a post-exposure bake (PEB) process (hereinafter referred to as “first PEB process”) if desired. ).

The wavelength used for the exposure is not particularly limited, and includes KrF excimer laser, ArF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation.
As the photomask, for example, a binary mask (Binary-Mask) in which the transmittance of the light shielding portion is 0% or a halftone phase shift mask (HT-Mask) in which the transmittance of the light shielding portion is 6% can be used.
The binary mask is generally formed by forming a chromium film, a chromium oxide film or the like as a light shielding portion on a quartz glass substrate.
As the halftone phase shift mask, generally, a quartz glass substrate on which a MoSi (molybdenum silicide) film, a chromium film, a chromium oxide film, a silicon oxynitride film, or the like is formed as a light shielding portion is used. .
Note that selective exposure may be performed by exposure without using a photomask, for example, drawing by EB or the like.

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

When the first PEB treatment is performed, the PEB treatment is performed at a baking temperature that increases the solubility of the first resist film in the alkaline developer.
In other words, the first resist film is made of a positive chemically amplified resist composition, and the resist film made of a positive chemically amplified resist composition is subjected to PEB treatment after exposure to produce an acid. The diffusion of the acid generated from the generator component in the resist film and the increase in the solubility of the resist film in the alkaline developer by the action of the acid proceed.
Specifically, for example, after selectively exposing the first resist film through a photomask having a predetermined pattern formed, the first PEB treatment is performed for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. Preferably it is applied for 60 to 90 seconds.

[Film Formation Step (2)]
On the first resist film obtained in the film forming step (1), a second chemically amplified resist composition is applied to form a second resist film. Similar to the first resist film, the second resist film can be formed by a conventionally known method.
As the second chemically amplified resist composition, either a positive resist composition or a negative resist composition described later may be used.
Note that the first PEB treatment is performed in the film formation step (1), and the pre-baking (PAB) treatment (hereinafter referred to as “second PAB treatment”) after applying the second chemically amplified resist composition in the film formation step (2). ), The difference between the temperature of the second PAB and the temperature of the first PEB treatment (“second PAB treatment temperature” — “first PEB treatment temperature”) is preferably minus 60 to plus 20 ° C. -40 to 0 ° C is more preferable. By setting the temperature of the second PAB treatment to the temperature of the first PEB treatment within the above range, both the first and second resist patterns can be formed satisfactorily. Further, by setting the temperature of the second PAB to be the same as or lower than the temperature of the first PEB treatment, the effect is further improved.
The thickness of the second resist film is preferably 50 to 500 nm, more preferably 50 to 450 nm. By setting it within this range, there are effects such that a resist pattern can be formed with high resolution and sufficient resistance to etching can be obtained.
In the present invention, the film thickness of the first resist film and the second resist film may be the same or different. When the film thicknesses of the first resist film and the second resist film are different, the aspect ratio between the resist pattern made of the first resist film and the resist pattern made of the second resist film changes. In normal patterning, if the aspect ratio of the resist pattern made of the first resist film is too high, it may cause pattern collapse, but in the resist pattern forming method of the present invention, the resist pattern made of the first resist film. Since the resist pattern made of the second resist film is integrally formed thereon, the resist pattern made of the second resist film becomes a reinforcing structure, and the resist pattern made of the first resist film can be formed with a high aspect ratio. It becomes possible. The ability to form such a high aspect ratio pattern is expected to expand the scope of application to nanotechnology.

Next, the second resist film is selectively exposed and post-exposure baking is performed. Specifically, for example, the first resist film formed as described above is selectively exposed through a photomask, and post-exposure baking (PEB) processing (hereinafter referred to as “second PEB processing”). Apply.
The selective exposure of the second resist film can be performed in the same manner as the selective exposure of the first resist film in the film forming step (1). For example, after selectively exposing the second resist film through a photomask on which a predetermined pattern is formed, the second PEB treatment is performed at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 90. For 2 seconds.
The wavelength used for the selective exposure of the second resist film may be the same as or different from the wavelength used for the selective exposure of the first resist film.
In addition, when performing a 1st PEB process in a film formation process (1), it is preferable that the temperature of a 2nd PEB process is the same temperature as the temperature of a 1st PEB process, or it lower temperature. Specifically, the temperature difference between the temperature of the first PEB treatment and the second PEB treatment is preferably 0 ° C. or more and less than 60 ° C., and more preferably 0 ° C. or more and less than 20 ° C.

[Patterning process]
In the patterning step, the first resist film and the second resist film obtained in the film forming step (1) and the film forming step (2) are developed to form a multilayer resist pattern.
Development can be carried out by a known method using an aqueous alkali solution, for example, an aqueous tetramethylammonium hydroxide (TMAH) solution having a concentration of 0.1 to 10% by mass.
After the alkali development, a rinse treatment with water or the like may be performed.
Further, after the alkali development, a baking process (post-bake) may be further performed. Post-baking is usually performed under the condition of about 100 ° C. (because it is performed for the purpose of removing water after alkali development or rinsing), and the processing time is preferably 30 to 90 seconds.

According to the resist pattern forming method of the present invention, a fine multilayer resist pattern having a complicated three-dimensional structure such as a hollow structure can be formed using a liquid resist such as a KrF resist or an ArF resist.
When forming a resist pattern having a complicated three-dimensional structure such as a hollow structure, it is necessary to form a smooth resist layer (that is, a resist layer having a uniform film thickness). In order to form the resist layer, a smooth support layer is required. In conventional methods such as double patterning, a first resist film is formed on a support, exposed and developed to form a first resist pattern, and the support on which the first resist pattern is formed A second resist film is formed thereon, exposed and developed to form a second resist pattern. Therefore, since the space portion in the first resist pattern is filled with the second resist film, a multilayer resist pattern having a hollow structure cannot be formed.
On the other hand, as described above, as a result of the study by the present inventors, in the method described in Patent Document 2, the pattern size that can be formed is limited to the order of several tens of micrometers, and several tens to several hundreds nanometers. It was found that miniaturization to the metric order is difficult.
On the other hand, in the resist pattern forming method of the present invention, the first resist film is formed and exposed, and then the second resist film is formed thereon without developing the first resist film. Finally, the first film and the second film are developed simultaneously. In the method of the present invention, the second resist layer can be formed thereon while keeping the first resist layer smooth as a support layer. As a result, a nano-order fine resist pattern having a hollow structure can be formed.
Further, as described above, in the resist pattern forming method of the present invention, since the resist pattern made of the second resist film is integrally formed on the resist pattern made of the first resist film, the second resist film is used. This resist pattern becomes a reinforcing structure, and a resist pattern made of the first resist film can be formed with a high aspect ratio. The ability to form such a high aspect ratio pattern is expected to expand the scope of application to nanotechnology. For example, in the dual damascene method, a via and a trench are formed simultaneously by forming a fine wiring pattern of a hollow structure having a T-shaped cross-sectional shape and the like, and by embedding Cu therein, both the via and the trench are formed at once. Since Cu is embedded, it is expected that the problem of controlling the Cu bonding interface can be solved.

(First chemically amplified resist composition)
In the resist pattern forming method of the present invention, a positive resist composition whose solubility in an alkaline developer is increased by exposure is used as the first chemically amplified resist composition.

≪Positive resist composition≫
The positive resist composition used as the first chemically amplified resist composition is not particularly limited, and exposure to be used from among many positive resist compositions conventionally proposed in ArF resists and the like. It can be appropriately selected and used according to the light source, lithography characteristics and the like.
The chemically amplified positive resist composition contains a base component (A) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component (B) that generates an acid upon exposure. Things are common.
In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the acid generator, and the action of the acid increases the solubility of the component (A) in an alkaline developer. Therefore, in the formation of the resist pattern, when selective exposure is performed on the resist film obtained using the positive resist composition, the solubility of the exposed portion of the resist film in an alkaline developer increases, Since the solubility of the unexposed portion in the alkaline developer does not change, the resist pattern can be formed by performing alkali development.

<(A) component>
In the present invention, the “base component” refers to an organic compound having a film forming ability.
As such a base component, an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 2000 or more are usually used. Hereinafter, a polymer having a molecular weight of 2000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight determined by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.

[(A1) component]
In the positive resist composition used as the first chemically amplified resist composition, the component (A) is preferably a resin component having a structural unit derived from an acrylate ester. Among these, the component (A) includes a resin component (A1) having a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group (hereinafter referred to as “(A1) component”). preferable.
In addition to the structural unit (a1), the component (A1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
In addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a2), the component (A1) is further an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. It is preferable to have a structural unit (a3) derived from
In addition to the structural unit (a1), the structural unit (a2), and the structural unit (a3), the component (A1) preferably has a structural unit (a5) described later.

Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include a lower alkyl group and a halogenated lower alkyl group.
The α-position (α-position carbon atom) of a structural unit derived from an acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
In the acrylate ester, as the lower alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, Examples include lower linear or branched alkyl groups such as isopentyl group and neopentyl group.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and is a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. In view of industrial availability, a hydrogen atom or a methyl group is most preferable.

・ Structural unit (a1)
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire resin (A1) hardly soluble in an alkali developer before dissociation, and is dissociated by an acid to dissociate this resin (A1). ) It increases the solubility in the entire alkaline developer, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure without aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically, a tert-butyl group or a 2-methyl-2-butyl group. 2-methyl-2-pentyl group, 3-methyl-3-pentyl group, and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), Etc.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. Examples thereof include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. And a group in which hydrogen atom is removed. Further, a part of carbon atoms constituting the ring of a group obtained by removing one or more hydrogen atoms from these monocycloalkanes or a group obtained by removing one or more hydrogen atoms from polycycloalkane is an etheric oxygen atom (- O-) may be substituted.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include:
(I) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto, and the like.
(I) Specific examples of the group having a tertiary carbon atom on the ring skeleton of the monovalent aliphatic cyclic group are represented by the following general formulas (1-1) to (1-9). Groups and the like.
(Ii) Specific examples of the group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-1) And the group represented by (2-6).

^{Wherein, R 14} represents an alkyl group, g is an integer of 0-8. ]

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

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

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

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

In the formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms in R ¹ ′ and R ² ′ include those similar to the alkyl group having 1 to 5 carbon atoms in R, and a methyl group or an ethyl group is preferable, and a methyl group is the most preferable. preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

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

As a C1-C5 alkyl group in Y, the same thing as the C1-C5 alkyl group in said R is mentioned.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

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

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

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

  Specific examples of the acetal type acid dissociable, dissolution inhibiting group include groups represented by the following formulas (p3-1) to (p3-12).

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents a divalent linking group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Examples of the divalent linking group for Y ² include an alkylene group, a divalent aliphatic cyclic group, and a divalent linking group containing a hetero atom.
As the aliphatic cyclic group, those similar to the explanation of the “aliphatic cyclic group” can be used except that a group in which two or more hydrogen atoms are removed is used.
When Y ² is an alkylene group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .
When Y ² is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero 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 or an acyl group), —S—. , —S (═O) ₂ —, —S (═O) ₂ —O—, a group represented by the formula —A—O—B—, a formula — [A—C (═O) —O] _m —. Examples thereof include a group represented by B-. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
Etc.

When Y ² is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When Y ² is the formula -A-O-B- or the formula-[A-C (= O) -O] _m -B-, A and B each independently have a substituent. It is also a good divalent hydrocarbon group.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.

  The hydrocarbon group in A 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 for A may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for A include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 or 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
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 - 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 —; Alkyl trimethylene groups such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH _{3) CH} 2 CH ₂ - alkyl, such as alkyl tetramethylene group such as Such as an alkylene group, and the like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above as a chain-like aliphatic group. And a group bonded to the terminal of the aromatic hydrocarbon group or interposed in the middle of the chain-like aliphatic hydrocarbon group.
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 a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

  A 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 most preferably a methylene group or an ethylene group. .

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene 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 — [A—C (═O) —O] _m —B—, m is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 Is more preferable and 1 is most preferable.
Y ² is preferably the alkylene group, divalent aliphatic cyclic group or divalent linking group containing a hetero atom. Among these, a divalent linking group containing a hetero atom is preferable, and a linear group having an oxygen atom as a hetero atom, for example, a group containing an ester bond is particularly preferable.
Among them, a group represented by the above-described —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _x —C (═O) —O— ( CH _{2) y} - group represented by are preferred.
x is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.
y is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

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

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3] Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

In the formula, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).

Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by general formula (a1-1) or (a1-3) is preferable, and specifically, (a1-1-1) to (a1-1-4), (a1-1-1-) It is more preferable to use at least one selected from the group consisting of 20) to (a1-1-23) and (a1-3-25) to (a1-3-28).
Furthermore, as the structural unit (a1), those represented by the following general formula (a1-1-01) that include structural units of the formula (a1-1-1) to the formula (a1-1-3), In the following general formula (a1-1-02) including the structural units of formulas (a1-1-16) to (a1-1-17) and formulas (a1-1-20) to (a1-1-23) Represented by the following general formula (a1-3-01) including structural units of the formulas (a1-3-25) to (a1-3-26), or the formula (a1-3- What is represented by the following general formula (a1-3-02) including the structural units of 27) to (a1-3-28) is also preferable.

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group.)

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² represents a lower alkyl group, and h represents an integer of 1 to 6.)

In general formula (a1-1-01), R is the same as defined above. The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.

In general formula (a1-1-02), R is the same as defined above. The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 or 2, and most preferably 2.

  In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 50 mol%, based on all structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a2)
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, the lactone-containing monocyclic group is a group in which one hydrogen atom is removed from a 4- to 6-membered ring lactone, for example, a group in which one hydrogen atom is removed from β-propionolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.

  More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ′ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or —COOR; R "is a hydrogen atom or an alkyl group; R ²⁹ is a single bond or a divalent linking group; s" is 0 or an integer of 1 to 2; A "is an oxygen atom or a sulfur atom. An alkylene group having 1 to 5 carbon atoms, an oxygen atom or a sulfur atom, and m is an integer of 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
R ²⁹ is a single bond or a divalent linking group. The divalent linking group is the same as the divalent linking group described for Y ² in the general formula (a1-0-2). Among them, an alkylene group and an ester bond (—C (═O ) -O-) or a combination thereof. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for A in Y ² can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to (a2) -3) At least 1 sort (s) selected from the group which consists of a structural unit represented by 3) is more preferable. Among these, from structural units represented by chemical formulas (a2-1-1), (a2-2-1), (a2-2-7), (a2-3-1) and (a2-3-5) It is preferable to use at least one selected from the group consisting of

  5-60 mol% is preferable with respect to the sum total of all the structural units which comprise a copolymer (A1), and the ratio of the structural unit (a2) in a copolymer (A1) is 10-50 mol% more. Preferably, 20-50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a3)
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
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). As the cyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. 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 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, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), (a3-3) ) And a structural unit represented by the structural unit represented by the formula (a3-4) are preferable.

(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) S is an integer of 1 to 3, d is an integer of 1 to 3, and e is 0 or 1.)

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 a hydroxyl group bonded to the 3-position of the adamantyl group is particularly preferred.

  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. These preferably have a 2-norbornyl group or a 3-norbornyl group 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.
In formula (a3-4), d is preferably 1 or 2, and more preferably 1. The bonding position of the hydroxyl group is not particularly limited, and when d is 1, the 2nd position is preferable because it is readily available and inexpensive. When d is 2 or 3, arbitrary substitution positions can be combined.
In formula (a3-4), e is preferably 1.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all the structural units constituting the component (A1). 25 mol% is more preferable.

・ Structural unit (a5)
The structural unit (a5) is a structural unit represented by the following general formula (a5-1).

[In Formula (a5-1), R is a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms or a halogenated lower alkyl group having 1 to 5 carbon atoms; Y ¹ is an aliphatic cyclic group; Is a monovalent organic group; a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b = 1 to 3; c, d, and e are each independently 0. It is an integer of ~ 3. ]

In the general formula (a5-1), R is the same as R ¹ in the formula (a0-1). Of these, R is preferably a hydrogen atom or a methyl group.

In general formula (a5-1), Y ¹ represents an aliphatic cyclic group.
Here, in the present specification and claims, the “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a5) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The structure of the basic ring (aliphatic ring) excluding the substituent of the “aliphatic cyclic group” is not limited to being a ring composed of carbon and hydrogen (hydrocarbon ring), but the ring (aliphatic ring) The ring structure may contain an oxygen atom. The “hydrocarbon ring” may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be either a polycyclic group or a monocyclic group. Examples of the aliphatic cyclic group include a monocycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group; a bicycloalkane, a tricycloalkane, or a tetracycloalkane. Groups obtained by removing two or more hydrogen atoms from polycycloalkanes and the like. More specifically, monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane are listed. .
Examples of the aliphatic cyclic group include two or more hydrogen atoms from tetrahydrofuran or tetrahydropyran which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. Examples include groups other than.
The aliphatic cyclic group in the structural unit (a5) is preferably a polycyclic group, and particularly preferably a group obtained by removing two or more hydrogen atoms from adamantane.

In the general formula (a5-1), Z is a monovalent organic group.
Here, in the present specification and claims, the “organic group” means a group containing a carbon atom, and an atom other than a carbon atom (for example, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom ( A fluorine atom, a chlorine atom, etc.).
As Z of the organic group, for example, which may have a substituent aliphatic hydrocarbon group, which may have a substituent, an aromatic hydrocarbon group represented by the formula -Q ⁵ -R ⁵ Group (wherein Q ⁵ is a divalent linking group, and R ⁵ is an aliphatic hydrocarbon group which may have a substituent or an aromatic hydrocarbon group which may have a substituent). Is mentioned.

  In the organic group of Z, the aliphatic hydrocarbon group is, for example, a linear, branched or cyclic saturated hydrocarbon group having 1 to 20 carbon atoms, or a linear or branched chain having 2 to 20 carbon atoms. And an aliphatic unsaturated hydrocarbon group.

Examples of the linear saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.
Examples of the branched saturated hydrocarbon group 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.

The linear or branched alkyl group may have a substituent. Examples of the substituent include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), a cyano group, and a carboxy group.
As the alkoxy group as a substituent of the linear or branched alkyl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n- A 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 alkyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
The halogenated alkyl group as a substituent for the aromatic group is a hydrogen atom of an alkyl group having 1 to 5 carbon atoms (preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc.). Examples thereof include a group in which part or all of the atoms are substituted with the halogen atom.

The cyclic saturated hydrocarbon group may be either a polycyclic group or a monocyclic group, and examples thereof include cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as monocycloalkane, bicycloalkane, and tricyclo. And groups obtained by removing one hydrogen atom from polycycloalkane such as alkane and tetracycloalkane. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Groups and the like.
The cyclic alkyl 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 exemplified as the substituent that the linear or branched alkyl group may have, an alkyl group having 1 to 5 carbon atoms, and the like.

Examples of the linear unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group.
Examples of the branched unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
The linear or branched unsaturated hydrocarbon group may have a substituent. Examples of the substituent include the same ones as those exemplified as the substituent which the linear or branched alkyl group may have.

In the organic group of Z, the aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
The aromatic organic group may have an aromatic hydrocarbon ring in which the ring skeleton of the aromatic ring is composed only of carbon atoms, and the aromatic ring group includes aromatic atoms containing hetero atoms other than carbon atoms. It may have a heterocyclic ring.
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. A heteroaryl group in which a part of carbon atoms constituting the ring of these aryl groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom; a benzyl group, a phenethyl group, 1 -Arylalkyl groups such as naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and the like. The alkyl chain in the arylalkyl group preferably has 1 to 4 carbon atoms, 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, etc. Examples include heteroarylalkyl groups in which a part of the atoms is substituted with the heteroatom.
Examples of the substituent of the aromatic group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and an acetyl group.
Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent of the aromatic group include those mentioned as the substituent that the linear or branched alkyl group may have. The same thing and a C1-C5 alkyl group are mentioned.

In the group represented by the formula -Q ⁵ -R ⁵ , Q ⁵ is a divalent linking group, and R ⁵ has an aliphatic hydrocarbon group or a substituent which may have a substituent. An aromatic hydrocarbon group that may be present.
Examples of the divalent linking group for Q ⁵ include the same groups as those exemplified in the description of R ² in the above formula (a0-1).
R ⁵ may be the same as those exemplified in the description of the aliphatic hydrocarbon group and aromatic hydrocarbon group in Z above.

Among them, the organic group of Z is a group containing an aliphatic hydrocarbon group which may have a substituent since the solubility in an organic solvent is further improved when a resist composition is formed. Preferably, the group represented by the formula -Q ⁵ -R ⁵ ′ (wherein Q ⁵ is a divalent linking group, and R ⁵ ′ is an aliphatic carbon which may have a substituent. It is more preferably a hydrogen group. Specifically, a tertiary alkyl group-containing group or an alkoxyalkyl group is preferable.

(Tertiary alkyl group-containing group)
Here, in the present specification and claims, the “tertiary alkyl group” refers to an alkyl group having a tertiary carbon atom. As described above, the “alkyl group” represents a monovalent saturated hydrocarbon group, and includes a chain (straight chain or branched chain) alkyl group and an alkyl group having a cyclic structure.
The “tertiary alkyl group-containing group” refers to a group containing a tertiary alkyl group in its structure. The tertiary alkyl group-containing group may be composed only of a tertiary alkyl group, or may be composed of a tertiary alkyl group and another atom or group other than the tertiary alkyl group. .
Examples of the “atom or group other than the tertiary alkyl group” that constitutes the tertiary alkyl group-containing group together with the tertiary alkyl group include a carbonyloxy group, a carbonyl group, an alkylene group, an oxygen atom, and the like. .

Examples of the tertiary alkyl group-containing group of Z include a tertiary alkyl group-containing group having no cyclic structure, a tertiary alkyl group-containing group having a cyclic structure, and the like.
The tertiary alkyl group-containing group having no cyclic structure is a group containing a branched tertiary alkyl group as the tertiary alkyl group and having no cyclic structure in the structure.
Examples of the branched tertiary alkyl group include groups represented by the following general formula (I).

In formula (I), R ^{21 to} R ²³ are each independently a linear or branched alkyl group. 1-5 are preferable and, as for carbon number of this alkyl group, 1-3 are more preferable.
Moreover, it is preferable that the total carbon number of group represented by general formula (I) is 4-7, it is more preferable that it is 4-6, and it is most preferable that it is 4-5.
Preferred examples of the group represented by the general formula (I) include a tert-butyl group and a tert-pentyl group, and a tert-butyl group is more preferable.

Examples of the tertiary alkyl group-containing group that does not have a cyclic structure include the above-described branched tertiary alkyl group; the above-described branched tertiary alkyl group is a linear or branched alkylene group A tertiary alkyl group-containing chain alkyl group bonded to the above; a tertiary alkyloxycarbonyl group having the branched tertiary alkyl group described above as the tertiary alkyl group; And tertiary alkyloxycarbonylalkyl groups having a branched tertiary alkyl group.
The alkylene group in the tertiary alkyl group-containing chain alkyl group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and still more preferably an alkylene group having 2 to 2 carbon atoms.
Examples of the chain-like tertiary alkyloxycarbonyl group include a group represented by the following general formula (II). ^R 21 ^{to R 23} in the formula (II) is the same as ^R 21 ^{to R 23} in general formula (I). The chain-like tertiary alkyloxycarbonyl group is preferably a tert-butyloxycarbonyl group (t-boc) or a tert-pentyloxycarbonyl group.

Examples of the chain-like tertiary alkyloxycarbonylalkyl group include a group represented by the following general formula (III). ^R 21 ^{to R 23} in the formula (III) are the same as ^R 21 ^{to R 23} in general formula (I). f is an integer of 1 to 3, and 1 or 2 is preferable. As the chain-like tertiary alkyloxycarbonylalkyl group, a tert-butyloxycarbonylmethyl group and a tert-butyloxycarbonylethyl group are preferable.
Of these, the tertiary alkyl group-containing group having no cyclic structure is preferably a tertiary alkyloxycarbonyl group or a tertiary alkyloxycarbonylalkyl group, more preferably a tertiary alkyloxycarbonyl group. A tert-butyloxycarbonyl group (t-boc) is most preferred.

The tertiary alkyl group-containing group having a cyclic structure is a group having a tertiary carbon atom and a cyclic structure in the structure.
In the tertiary alkyl group-containing group having a cyclic structure, the cyclic structure preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and more preferably 6 to 10 carbon atoms constituting the ring. Most preferred. Examples of the cyclic structure include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Preferable examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

Examples of the tertiary alkyl group-containing group having a cyclic structure include a group having the following group (1) or (2) as a tertiary alkyl group.
(1) A group in which a linear or branched alkyl group is bonded to a carbon atom constituting a ring of a cyclic alkyl group (cycloalkyl group), and the carbon atom is a tertiary carbon atom.
(2) A group in which an alkylene group having a tertiary carbon atom (branched alkylene group) is bonded to the carbon atom constituting the ring of the cycloalkyl group.

The linear or branched alkyl group in the group (1) preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. .
Examples of the group (1) include a 2-methyl-2-adamantyl group, a 2-ethyl-2-adamantyl group, a 1-methyl-1-cycloalkyl group, and a 1-ethyl-1-cycloalkyl group.

In the above (2), the cycloalkyl group to which the branched alkylene group is bonded may have a substituent. Examples of the substituent include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).
Examples of the group (2) include groups represented by the following chemical formula (IV).

In the formula (IV), R ²⁴ is a cycloalkyl group which may or may not have a substituent. Examples of the substituent that the cycloalkyl group may have include a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (═O).
R ²⁵ and R ²⁶ are each independently a linear or branched alkyl group, and the alkyl group is the same as the alkyl group of R ^{21 to} R ²³ in the formula (I). Can be mentioned.

(Alkoxyalkyl group)
Examples of the alkoxyalkyl group for Z include groups represented by the following general formula (V).

Wherein, R ⁴¹ represents a linear, branched or cyclic alkyl group.
When R ⁴¹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ⁴¹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. For example, one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group And the like except for. More specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. . Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
^R42 is a linear or branched alkylene group. The alkylene group preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and still more preferably 1 to 2 carbon atoms.
As the alkoxyalkyl group for Z, a group represented by the following general formula (VI) is particularly preferable.

In the formula (VI), R ⁴¹ is the same as described above, and R ⁴³ and R ⁴⁴ are each independently a linear or branched alkyl group or a hydrogen atom.
In R ⁴³ and R ⁴⁴ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ⁴³ and R ⁴⁴ is a hydrogen atom and the other is a methyl group.

  Among these, as Z, a tertiary alkyl group-containing group is preferable, a group represented by the general formula (II) is more preferable, and a tert-butyloxycarbonyl group (t-boc) is most preferable.

In the general formula (a5-1), a is an integer of 1 to 3, b is an integer of 0 to 2, and a + b = 1 to 3.
a is preferably 1.
b is preferably 0.
a + b is preferably 1.
c is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
d is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
e is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

  As the structural unit (a5), a structural unit represented by general formula (a5-1-1) or (a5-1-2) shown below is particularly desirable.

[Wherein R, Z, b, c, d and e are the same as defined above. ]

[Wherein R, Z, a, b, c, d and e are the same as defined above. c ″ is an integer of 1 to 3.]

In the formula (a5-1-2), c ′ is an integer of 1 to 3, preferably 1 or 2, and more preferably 1.
When c in the formula (a5-1-2) is 0, the oxygen atom at the terminal of the carbonyloxy group (—C (═O) —O—) of the acrylate ester is bonded to the oxygen atom in the cyclic group. It is preferable that they are not bonded to carbon atoms to be bonded. That is, when c is 0, there are two or more carbon atoms between the terminal oxygen atom and the oxygen atom in the cyclic group (the number of carbon atoms is 1 (that is, acetal bond and It is preferable that the above is excluded).

  The monomer for deriving the structural unit (a5) is, for example, a compound represented by the following general formula (a5-1 ′) (an acrylate ester containing an aliphatic cyclic group having 1 to 3 alcoholic hydroxyl groups). It can be synthesized by protecting a part or all of the hydroxyl groups with an organic group (preferably a tertiary alkyl group-containing group or an alkoxyalkyl group) using a known method.

[Wherein, R, Y ¹ , a, b, c, d, and e are the same as defined above. ]

As the structural unit (a5), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.
The proportion of the structural unit (a5) in the component (A1) is preferably 1 to 45 mol%, and preferably 5 to 45 mol%, based on the total of all structural units constituting the component (A1). More preferably, it is more preferably 5 to 40 mol%, and most preferably 5 to 35 mol%. By setting it to the lower limit value or more, the solubility in organic solvents is improved, and when it is the upper limit value or less, the balance with other structural units is good.

・ Structural unit (a4)
The component (A1) may contain other structural units (a4) other than the structural units (a1) to (a3) and (a5) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the structural units (a1) to (a3) and (a5) described above. For the ArF excimer laser and the KrF excimer laser ( A number of hitherto known materials can be used that are preferably used for resist resins such as ArF excimer laser).
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). 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 represented by the following general formulas (a4-1) to (a4-5).

(In the formula, R is as defined above.)

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

  In the present invention, the component (A1) is preferably a copolymer having the structural unit (a1). Examples of such a copolymer include a copolymer consisting of the structural units (a1) and (a2) described above. Copolymer, copolymer consisting of structural units (a1) and (a3); copolymer consisting of structural units (a1), (a2) and (a3); the above structural units (a1), (a2) and (a3) And a copolymer comprising (a4); a copolymer comprising the above structural units (a1), (a2), (a3) and (a5).

  In the present invention, the component (A1) preferably contains the following combination of structural units.

[Wherein, R is the same as defined above, and a plurality of R may be the same or different. R ²⁰ is a lower alkyl group. ]

[Wherein, R, R ^{21 to} R ²³ and e are the same as defined above, and the plurality of R may be the same or different. R ²⁰ is a lower alkyl group. ]

In formulas (A1-11) and (A1-12), the lower alkyl group for R ^{20 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group, and more preferably a methyl group.

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

The weight average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000 to 20000. Most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. 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, the effects such as lithography characteristics are improved.

In the positive resist composition used as the first chemically amplified resist composition, the component (A) does not correspond to the component (A1), and is a base material component whose solubility in an alkaline developer is increased by the action of an acid. It may contain.
That is, the component (A) may be the component (A1) or a resin component not corresponding to the component (A1). It may be a compound component (A2) (hereinafter also referred to as “component (A2)”) or a mixture thereof. Among these, it is preferable that (A) component contains the said (A1) component.

  Examples of the resin component that does not correspond to the component (A1) include a number of hitherto known materials used for resist resins such as for ArF excimer laser and KrF excimer laser, such as polyhydroxystyrene (PHS). ) Or a hydroxyl group thereof protected with an acid dissociable, dissolution inhibiting group (PHS resin), a resin (acrylic resin) having a structural unit derived from a (meth) acrylate ester other than the component (A1). Resin).

[(A2) component]
The component (A2) is preferably a low molecular compound having a molecular weight of 500 or more and less than 4000 and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1). Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a soluble dissolution inhibiting group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2, 3, 4 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol or xylenol. Of course, it is not limited to these.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

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

<(B) component>
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, and poly (bissulfonyl) diazomethanes. 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.

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; among R ¹ ″ to R ³ ″ in formula (b-1), Any two may be bonded together to form a ring with the sulfur atom in the formula; R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group; R ¹ At least one of “˜R ³ ” represents an aryl group, and at least one of “R ⁵ ″ to R ⁶ ” represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. In addition, 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.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl or alkoxy. It may or may not be substituted with a group, a halogen atom, a hydroxyl group or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, Most preferred is a tert-butoxy group.
The alkoxy group that may be substituted with a hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may substitute the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group, respectively.

When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

Preferable examples of the cation moiety of the compound represented by the formula (b-1) include cation moieties represented by the following formulas (I-1-1) to (I-1-10). Among these, those having a triphenylmethane skeleton such as a cation moiety represented by formulas (I-1-1) to (I-1-8) are preferable.
In the following formulas (I-1-9) to (I-1-10), R ⁹ and R ¹⁰ are each independently a phenyl group, naphthyl group or carbon number 1 to 5 which may have a substituent. An alkyl group, an alkoxy group, and a hydroxyl group.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

R ⁴ ″ represents a linear, branched or cyclic alkyl group or a fluorinated alkyl group.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group is a cyclic group as indicated by R ¹ ″ and preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and more preferably 6 carbon atoms. Most preferably, it is -10.
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. The fluorination rate of the fluorinated alkyl group (ratio of fluorine atoms in the alkyl group) is preferably 10 to 100%, more preferably 50 to 100%. Particularly, all the hydrogen atoms are substituted with fluorine atoms. A fluorinated alkyl group (perfluoroalkyl group) is preferable because the strength of the acid is increased.
R ⁴ ″ is most preferably a linear or cyclic alkyl group or a fluorinated alkyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by the formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or the same 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) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate 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.
In addition, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

[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 substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, 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 The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  Moreover, the onium salt type | system | group acid generator represented by the following general formula (b-1) 'or (b-2)' can also be used.

(In the formula, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ are the same as described above.)

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ 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.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion moiety represented by the above general formula (b-3) or (b-4), etc. Among these, a fluorinated alkylsulfonic acid ion is preferable, and a fluorinated alkylsulfonic acid having 1 to 4 carbon atoms. Ion is more preferable, and linear perfluoroalkylsulfonic acid ions having 1 to 4 carbon atoms are particularly preferable, and specific examples thereof include trifluoromethylsulfonic acid ions, heptafluoro-n-propylsulfonic acid ions, and nonafluoro-n. -Butyl sulfonate ion etc. are mentioned.

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

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

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

As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

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

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

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

In the general formula (B-2), alkyl or halogenated alkyl group having no substituent group for R ³³ preferably has 1 to 10 carbon atoms, 1 to 8 carbon atoms, more preferably, carbon Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

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

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
[(D) component]
The positive resist composition used as the first chemically amplified resist composition may further contain a nitrogen-containing organic compound component (D) (hereinafter referred to as “component (D)”) as an optional component. preferable.
The component (D) is not particularly limited as long as it acts as an acid diffusion control agent, that is, a quencher that traps the acid generated from the component (B) by exposure, and a wide variety of components have been proposed. Therefore, any known one may be used, and aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are particularly preferable.
Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 carbon atoms.

Examples of the aliphatic amine include an amine (alkylamine 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 20 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 amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are 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.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, and tribenzylamine.
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} ethylamine and the like.

These may be used alone or in combination of two or more.
(D) 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.

[(E) component]
The positive resist composition of the present invention includes, as optional components, organic carboxylic acids, phosphorus oxoacids and derivatives thereof for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group consisting of (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 a lower alkyl group having 1 to 5 carbon atoms, 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 such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
As the component (E), an organic carboxylic acid is preferable, and salicylic acid is particularly preferable.
(E) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

  The positive resist composition of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

[(S) component]
The positive resist composition of the present invention can be produced by dissolving a resist material in an organic solvent (hereinafter referred to as “(S) component”).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ether alkyl such as ether, monopropyl ether, monobutyl ether or monophenyl ether Derivatives of polyhydric alcohols such as compounds having a propylene glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME) among these]; cyclic ethers such as dioxane, methyl lactate, Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, Aromatic organics such as dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene A solvent etc. can be mentioned.

(S) A component may be used independently and may be used as 2 or more types of mixed solvents.
Of these, PGMEA, PGME, 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 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.
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.

  The amount of the component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is preferable. Is used in a range of 0.5 to 20% by mass, more preferably 1 to 15% by mass.

(Second chemically amplified resist composition)
In the resist pattern forming method of the present invention, as the second chemically amplified resist composition, a positive resist composition whose solubility in an alkali developer is increased by exposure may be used, or for the alkali developer by exposure. You may use the negative resist composition in which solubility decreases.

≪Positive resist composition≫
The positive resist composition used as the second chemically amplified resist composition is not particularly limited, and exposure to be used from among many positive resist compositions conventionally proposed in ArF resists and the like. It can be appropriately selected and used according to the light source, lithography characteristics and the like.
The positive resist composition used as the second chemically amplified resist composition includes a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator that generates an acid upon exposure. What melt | dissolves a component (B) in the organic solvent (S) is common.

  In the positive resist composition used as the second chemically amplified resist composition, the component (A) and the component (B) are the same as those in the positive resist composition used as the first chemically amplified resist composition. The same thing as (A) component and (B) component is mentioned.

[(S) component]
The component (S) preferably contains an organic solvent that does not dissolve the first resist film (hereinafter referred to as “(S ₂ ) component”).
When the (S) component includes the (S ₂ ) component, the shape of the resist pattern made of the first resist film is favorable when the first resist film and the second resist film are developed in the patterning step. Thus, a resist pattern having a hollow structure can be stably formed.
Here, “does not dissolve the first resist film” means that a positive resist composition used as the first chemically amplified resist composition is applied on a support and dried, When a resist film having a thickness of 0.2 μm is formed and immersed in the organic solvent, the resist film disappears or does not change significantly even after 60 minutes (preferably the resist The film thickness is not 0.16 μm or less.)
In the positive resist composition used as the second chemically amplified resist composition, as the (S) component, the (S ₂ ) component may be used alone or as the first chemically amplified resist composition. You may use together with what was illustrated in description about (S) component in the positive resist composition obtained.

As the component (S ₂ ), those that do not dissolve the first resist film and dissolve each component of the positive resist composition used as the second chemically amplified resist composition are preferable. Examples thereof include alcohol-based organic solvents, fluorine-based organic solvents, and ether-based organic solvents having no hydroxyl group. Any one of these may be used alone, or two or more thereof may be mixed and used. Alcohol-based organic solvents are preferred from the standpoint of applicability and solubility of materials such as resin components.
Here, the “alcohol-based organic solvent” is a compound in which at least one of the hydrogen atoms of the aliphatic hydrocarbon is substituted with a hydroxyl group, and is a compound that is liquid at normal temperature and normal pressure. The structure of the main chain constituting the aliphatic hydrocarbon may be a chain structure, may be a cyclic structure, may have a cyclic structure in the chain structure, The chain structure may contain an ether bond.
The “fluorine-based organic solvent” is a compound containing a fluorine atom and is a liquid at normal temperature and normal pressure.
The “ether-based organic solvent having no hydroxyl group” is a compound that has an ether bond (C—O—C) in its structure, has no hydroxyl group, and is liquid at normal temperature and pressure. The ether-based organic solvent having no hydroxyl group preferably further has no carbonyl group in addition to the hydroxyl group.

As the alcohol-based organic solvent, monohydric alcohols are more preferable. Among them, primary or secondary monohydric alcohols are preferable, and primary monohydric alcohols are most preferable, depending on the number of carbon atoms.
Here, the monohydric alcohol means a case where the number of hydroxy groups contained in the alcohol molecule is 1, and does not include dihydric alcohol, trihydric alcohol and derivatives thereof.
The boiling point of the alcohol-based organic solvent is preferably 80 to 160 ° C., more preferably 90 to 150 ° C., and preferably 100 to 135 ° C., coating properties, stability of composition during storage, and PAB process. And the most preferable from the viewpoint of the heating temperature in the PEB process.

Examples of such alcohol-based organic solvents include monohydric alcohols and dihydric alcohols. Specifically, propylene glycol (PG); 1-butoxy-2-propanol (BP), n- Hexanol, 2-heptanol, 3-heptanol, 1-heptanol, 5-methyl-1-hexanol, 6-methyl-2-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2-ethyl- 1-hexanol, 2- (2-butoxyethoxy) ethanol, n-pentyl alcohol, s-pentyl alcohol, t-pentyl alcohol, isopentyl alcohol, isobutanol (also referred to as isobutyl alcohol or 2-methyl-1-propanol) , Isopropyl alcohol, 2 Examples include ethyl butanol, neopentyl alcohol, n-butanol, s-butanol, t-butanol, 1-propanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol and the like. It is done.
In addition, those having a cyclic structure include cyclopentanemethanol, 1-cyclopentylethanol, cyclohexanol, cyclohexanemethanol (CM), cyclohexaneethanol, 1,2,3,6-tetrahydrobenzyl alcohol, exo-norbornol, 2-methylcyclohexane. Examples include hexanol, cycloheptanol, 3,5-dimethylcyclohexanol, and benzyl alcohol.

  Among alcohol-based organic solvents, a monohydric alcohol having a chain structure is preferable, such as 1-butoxy-2-propanol (BP); isobutanol (2-methyl-1-propanol), 4-methyl-2-pentanol, n-Butanol is preferred, and isobutanol (2-methyl-1-propanol) and 1-butoxy-2-propanol (BP) are most preferred.

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

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

In the above formula, examples of the hydrocarbon group for R ⁴⁰ and R ⁴¹ include an alkyl group and an aryl group, and an alkyl group is preferred. Among ^them, it is preferable that any of R ^{40, R 41} is an alkyl ^group, more preferably a ^{R 40} and ^{R 41} are the same alkyl group.
As each of the alkyl groups of R ^40, R ^41, not particularly limited, for example, straight, branched or cyclic alkyl group, and the like. In the alkyl group, part or all of the hydrogen atoms may or may not be substituted with a halogen atom or the like.
The alkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, because the coating properties of the resist composition are good. Specific examples include an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a cyclopentyl group, and a hexyl group, and an n-butyl group and an isopentyl group are particularly preferable. .
The halogen atom that may be substituted for the hydrogen atom of the alkyl group is preferably a fluorine atom.
Each aryl group for R ⁴⁰ and R ⁴¹ is not particularly limited, and is, for example, an aryl group having 6 to 12 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups, It may or may not be substituted with a halogen atom or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specifically, a phenyl group, a benzyl group, a naphthyl group, etc. are mentioned, for example.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is more preferable.
As the alkoxy group which may substitute the hydrogen atom of the said aryl group, a C1-C5 alkoxy group is preferable and a methoxy group and an ethoxy group are more preferable.
The halogen atom that may substitute the hydrogen atom of the aryl group is preferably a fluorine atom.
In the above formula, R ⁴⁰ and R ⁴¹ may combine to form a ring.
R ⁴⁰ and R ⁴¹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 10 carbon atoms), and the end of R ^{40 and} the end of R ⁴¹ are bonded to each other. To form a ring. In addition, the carbon atom of the alkylene group may be substituted with an oxygen atom.
Specific examples of such ether-based organic solvents include 1,8-cineol, tetrahydrofuran, dioxane and the like.

The boiling point (under normal pressure) of the ether-based organic solvent having no hydroxyl group is preferably 30 to 300 ° C, more preferably 100 to 200 ° C, and further preferably 140 to 180 ° C. By being equal to or higher than the lower limit of the temperature range, the component (S) is less likely to evaporate during spin coating during application of the resist composition, so that application unevenness is suppressed and application properties are improved. On the other hand, by being below the upper limit, the (S) component is sufficiently removed from the resist film by pre-baking, and the formability of the second resist film is improved. Moreover, when the temperature is within this range, the effect of reducing the film thickness of the resist pattern and the stability of the composition during storage are further improved. Moreover, it is preferable also from a viewpoint of the heating temperature of a PAB process or a PEB process.
Specific examples of ether organic solvents having no hydroxyl group include, for example, 1,8-cineol (boiling point 176 ° C.), dibutyl ether (boiling point 142 ° C.), diisopentyl ether (boiling point 171 ° C.), dioxane (boiling point 101 ° C.). ), Anisole (boiling point 155 ° C.), ethyl benzyl ether (boiling point 189 ° C.), diphenyl ether (boiling point 259 ° C.), dibenzyl ether (boiling point 297 ° C.), phenetole (boiling point 170 ° C.), butyl phenyl ether, tetrahydrofuran (boiling point 66 ° C.) ), Ethyl propyl ether (boiling point 63 ° C.), diisopropyl ether (boiling point 69 ° C.), dihexyl ether (boiling point 226 ° C.), dipropyl ether (boiling point 91 ° C.) and the like.
The ether-based organic solvent having no hydroxyl group is preferably a cyclic or chain-shaped ether-based organic solvent because it has a good effect of reducing the film loss of the resist pattern, and among them, 1,8-cineole, dibutyl ether. And at least one selected from the group consisting of diisopentyl ether is preferred.

In the component (S), the organic solvents can be used alone or in combination.
The amount of component (S) to be used is not particularly limited, and usually an amount is used in which the chemically amplified resist composition becomes a liquid having a concentration that can be applied onto a support.

The positive resist composition used as the second chemically amplified resist composition preferably further contains a nitrogen-containing organic compound component (D) as an optional component, and includes an organic carboxylic acid and a phosphorus oxoacid. And at least one compound (E) selected from the group consisting of derivatives thereof. Examples of the component (D) and the component (E) are the same as the component (D) and the component (E) in the positive resist composition used as the first chemically amplified resist composition.
In addition, the positive resist composition used as the second chemically amplified resist composition further has miscible additives as desired, for example, additional resins for improving the performance of the resist film, and improved coating properties. A surfactant, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like can be appropriately added and contained.

≪Negative resist composition≫
The negative resist composition used as the second chemically amplified resist composition is a resin (alkali-soluble resin) component (A ′) soluble in an alkali developer (hereinafter referred to as “component (A ′)”). The acid generator component (B ′) component (hereinafter referred to as “(B ′) component”) and the crosslinking agent component (C ′) (hereinafter referred to as “(C ′) component”) that generate acid upon exposure are organic. What is generally dissolved in a solvent (S ′) (hereinafter referred to as “(S ′) component”) is common.
In such a negative resist composition, when an acid is generated from the component (B ′) by exposure, cross-linking occurs between the component (A ′) and the component (C ′) by the action of the acid, so that an alkaline developer is formed. On the other hand, it changes from soluble to insoluble in an alkaline developer. Therefore, in the formation of a resist pattern, when the resist film obtained by applying the negative resist composition on a support such as a substrate is selectively exposed, the exposed portion becomes insoluble in an alkaline developer. On the other hand, since the unexposed portion remains soluble in the alkali developer and does not change, alkali development can be performed.
There is no restriction | limiting in particular as a negative resist composition used as a 2nd chemically amplified resist composition, According to an exposure light source, a lithography characteristic, etc., it selects from a well-known negative resist composition suitably, and uses it. Can do.

[(A ′) component]
As the component (A ′), an exposure light source used at the time of resist pattern formation is proposed as an alkali-soluble resin such as a conventional chemically amplified negative resist composition for KrF and an ArF negative resist composition. Depending on the type, it can be appropriately selected. Specific examples include novolak resins having a hydrophilic group (hydroxyl group, carboxy group, etc.), PHS resins, and acrylic resins. Any of these may be used alone or in combination of two or more.
The component (A ′) in the negative resist composition used as the second chemically amplified resist composition is a fluorinated hydroxyalkyl group (for example, a general formula (a1′-1-1) described later). An alkali-soluble resin having a group or the like) is preferable.
As a preferable example of the component (A ′), specifically, for example, a resin (A1 ′) having a structural unit (a1 ′) having an aliphatic cyclic group having a fluorinated hydroxyalkyl group in the main chain. Can be mentioned.
Moreover, as a suitable thing of (A ') components other than resin (A1'), the structural unit containing the aliphatic cyclic group which has a fluorinated hydroxyalkyl group, for example, Preferably, it contains a hydroxyl group further Resin (A2) having a structural unit derived from an acrylate ester containing an aliphatic cyclic group and / or a structural unit not having a cyclic structure and derived from acrylic acid having an alcoholic hydroxyl group in the side chain ').
Moreover, as a suitable thing of (A ') component other than resin (A1') and (A2 '), resin (A3') which has the structural unit induced | guided | derived from hydroxystyrene is mentioned.

[Resin (A1 ′)]
The resin (A1 ′) includes a structural unit (a1 ′) having an aliphatic cyclic group having a fluorinated hydroxyalkyl group in the main chain.
In addition to the structural unit (a1 ′), the resin (A1 ′) preferably further includes a structural unit (a2 ′) having a hydroxyalkyl group.

・ Structural unit (a1 ′)
In the structural unit (a1 ′), “aliphatic cyclic group having a fluorinated hydroxyalkyl group” means that a fluorinated hydroxyalkyl group is bonded to a carbon atom constituting the ring of the aliphatic cyclic group. Means the group.
Further, “having an aliphatic cyclic group in the main chain” means that at least one, preferably two or more carbon atoms on the ring of the aliphatic cyclic group have the main chain of the resin (A1 ′). It means to compose.
In the present invention, when the component (A ′) contains the resin (A1 ′) having the structural unit (a1 ′), the solubility in an alkali developer is increased, and the resist pattern shape and line width roughness (LWR) are increased. Lithographic properties such as are improved. Further, by having an aliphatic cyclic group (for example, a structure of norbornane or tetracyclododecane) in the main chain, the carbon density is increased and the etching resistance is also improved.

Here, the “fluorinated hydroxyalkyl group” is a hydroxyalkyl group in which part of the hydrogen atoms of the alkyl group is substituted with a hydroxy group, and part or all of the remaining hydrogen atoms in the hydroxyalkyl group are It is substituted by a fluorine atom.
In a fluorinated hydroxyalkyl group, the hydrogen atom of the hydroxy group is easily released by fluorination.
In the fluorinated hydroxyalkyl group, the alkyl group is preferably a linear or branched alkyl group. Although carbon number of this alkyl group is not specifically limited, 1-20 are preferable, 4-16 are more preferable, and it is most preferable that it is 4-12.
The number of hydroxy groups in the fluorinated hydroxyalkyl group is not particularly limited, but is preferably one.

The fluorinated hydroxyalkyl group is a group in which a fluorinated alkyl group and / or a fluorine atom is bonded to the carbon atom to which the hydroxy group is bonded (here, the α-position carbon atom of the hydroxyalkyl group). Is preferred.
Here, in the fluorinated alkyl group bonded to the α-position, it is preferable that all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms. Further, the alkyl group of the fluorinated alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and more preferably 1 carbon atom.

The aliphatic cyclic group in the “aliphatic cyclic group having a fluorinated hydroxyalkyl group” may be a monocyclic group or a polycyclic group. In the structural unit (a1 ′), the aliphatic cyclic group is preferably polycyclic because it is excellent in etching resistance and the like.
An aliphatic cyclic group is a hydrocarbon group composed of carbon and hydrogen (alicyclic group), and a part of the carbon atoms constituting the ring of the alicyclic group is a heterogeneous group such as an oxygen atom, a nitrogen atom, or a sulfur atom. Heterocyclic groups and the like substituted with atoms are included. These aliphatic cyclic groups may have a substituent, and examples of the substituent include an alkyl group having 1 to 5 carbon atoms.
Here, “having a substituent” means that part or all of the hydrogen atoms bonded to the carbon atoms constituting the ring of the aliphatic cyclic group are substituted with a substituent (atom or group other than a hydrogen atom). Means that In the present invention, the alicyclic group is preferable as the aliphatic cyclic group.
The aliphatic cyclic group may be either saturated or unsaturated, but is preferably saturated because it is highly transparent to ArF excimer laser and the like, and has excellent resolution and depth of focus (DOF). .
It is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the aliphatic cyclic group include the following.
Examples of the monocyclic group include groups in which two or more hydrogen atoms have been removed from a cycloalkane. More specifically, a group in which two or more hydrogen atoms have been removed from cyclopentane or cyclohexane can be mentioned, and a group in which two or more hydrogen atoms have been removed from cyclohexane is preferred.
Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. More specifically, a group obtained by removing two or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like can be given.
Such an aliphatic cyclic group can be appropriately selected and used from among a large number of proposed resins for photoresist compositions for ArF excimer laser processes, for example.
Among these, a group obtained by removing two or more hydrogen atoms from cyclohexane, adamantane, norbornane, or tetracyclododecane is preferable because it is easily available from an industrial viewpoint.
Among these exemplified alicyclic groups, a group obtained by removing three hydrogen atoms from norbornane or tetracyclododecane is preferable, as in the structural unit (a1′-1) described later, and in particular, three hydrogen atoms from norbornane. A group excluding is preferred.

  Preferred examples of the structural unit (a1 ′) include structural units (a1′-1) represented by general formula (a1′-1) shown below. By including the structural unit (a1′-1), solubility in an alkali developer is particularly improved. Also, lithography properties such as resolution are improved.

[In the formula, Z is a fluorinated hydroxyalkyl group, and r is 0 or 1. ]

In the formula (a1′-1), r is 0 or 1, and is preferably 0 because it is easily available industrially.
In the formula (a1′-1), examples of the “fluorinated hydroxyalkyl group” represented by Z are the same as those described above.
Among these, Z is preferably a group represented by the following general formula (a1′-1-1) because the resist pattern shape is excellent and line edge roughness (LER) is reduced. “Line edge roughness (LER)” refers to uneven unevenness on the side wall of a line.

[Wherein, R ¹¹ ″ and R ¹² ″ are each independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, m ″ and n ″ are each independently an integer of 1 to 5, q Is an integer of 1-5. ]

In formula (a1′-1-1), R ¹¹ ″ and R ¹² ″ each independently represent a hydrogen atom or a lower alkyl group.
The lower alkyl group is preferably a linear or branched lower alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a tert-butyl group. , A pentyl group, an isopentyl group, a neopentyl group, and the like, and a methyl group is preferable.
Among these, it is preferable that R ¹¹ ″ and R ¹² ″ are both hydrogen atoms.
q is an integer of 1 to 5, more preferably an integer of 1 to 3, and most preferably 1.
m ″ and n ″ are each independently an integer of 1 to 5, more preferably an integer of 1 to 3. In particular, m ″ and n ″ are preferably 1 because of excellent synthesis.

As the structural unit (a1 ′), one type or a mixture of two or more types can be used.
In the resin (A1 ′), the proportion of the structural unit (a1 ′) is preferably 50 to 90 mol% and more preferably 55 to 90 mol% with respect to the total of all the structural units constituting the resin (A1 ′). 60 to 80 mol% is more preferable. The effect by containing a structural unit (a1 ') improves by being more than the lower limit of the said range, and a balance with another structural unit becomes favorable by being below an upper limit.

・ Structural unit (a2 ′)
The resin (A1 ′) preferably further contains a structural unit (a2 ′) having a hydroxyalkyl group in addition to the structural unit (a1 ′).
In the present invention, when the component (A ′) contains the resin (A1 ′) having such a structural unit (a2 ′), the solubility in an alkali developer is improved. In addition, the crosslinkability with the component (C ′) is increased, the difference in solubility (contrast) in the alkaline developer between the exposed portion and the unexposed portion is increased, and the negative resist composition functions more fully. Can do.
Examples of the structural unit (a2 ′) include a structural unit (a210 ′) having an aliphatic cyclic group having a hydroxyalkyl group in the main chain, and a structural unit derived from an acrylate ester having a hydroxyl group-containing alkyl group ( a220 ′) and the like are preferably used.
These structural units (a2 ′) can be used alone or in combination of two or more.

..Structural unit (a210 ')
In the present invention, the structural unit (a210 ′) is a structural unit having an aliphatic cyclic group having a hydroxyalkyl group in the main chain.
As the structural unit (a210 ′), in the “fluorinated hydroxyalkyl group” of the structural unit (a1 ′), a non-fluorinated hydroxyalkyl group, that is, a part of hydrogen atoms of the alkyl group is a hydroxy group. The structural unit similar to the structural unit (a1 ′) is preferable except that the remaining hydrogen atom in the substituted hydroxyalkyl group is not substituted with a fluorine atom.
Preferred examples of the structural unit (a210 ′) include structural units (a2′-1) represented by general formula (a2′-1) shown below. By including the structural unit (a2′-1), lithography characteristics such as a resist pattern shape and line width roughness (LWR) are improved. In addition, good contrast is easily obtained and etching resistance is improved.

Wherein R ¹³ ″ and R ¹⁴ ″ are each independently a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, Y ′ is a hydrogen atom or a hydroxyalkyl group, and r is 0 or 1. , G is an integer of 1 to 3. ]

The structural unit (a2′-1) represented by the general formula (a2′-1) is a structural unit having a norbornane or tetracyclododecane structure having a hydroxyalkyl group in the main chain.
In formula (a2′-1), R ¹³ ″ and R ¹⁴ ″ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. As the lower alkyl group, the same as the lower alkyl groups represented by R ¹¹ ″ and R ¹² ″ in formula (a1′-1-1) can be exemplified. Among these, it is preferable that R ¹³ ″ and R ¹⁴ ″ are both hydrogen atoms.
Y ′ is a hydrogen atom or a hydroxyalkyl group.
The hydroxyalkyl group is preferably a linear or branched hydroxyalkyl group having 10 or less carbon atoms, more preferably a linear or branched hydroxyalkyl group having 8 or less carbon atoms, and further preferably Is a linear lower hydroxyalkyl group having 1 to 3 carbon atoms.
The number of hydroxyl groups and the bonding position in the hydroxyalkyl group are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.
Y ′ is particularly preferably a hydrogen atom.
r is 0 or 1, and 0 is preferable.
g is an integer of 1 to 3, preferably 1 or 2, and most preferably 1.

  Specific examples of the structural unit (a2′-1) include structural units represented by the following chemical formulas (a2′-1-1) to (a2′-1-7).

Among these, the above chemical formulas (a2′-1-1), (a2′-1-2), and (a2′-1-3) are preferable.
As the structural unit (a210 ′), one type or a mixture of two or more types can be used.
10-50 mol% is preferable with respect to the sum total of all the structural units which comprise resin (A1 ') in resin (A1'), and the ratio of structural unit (a210 ') is more preferable 15-50 mol%. 20 to 45 mol% is more preferable. By being more than the lower limit of the above range, the effect of containing the structural unit (a210 ′) such that alkali solubility is improved and good contrast is easily obtained is improved. On the other hand, the balance with other structural units becomes favorable by being below an upper limit.

..Structural unit (a220 ')
The structural unit (a220 ′) is a structural unit derived from an acrylate ester having a hydroxyl group-containing alkyl group.
Hydroxyl group-containing alkyl groups can be broadly classified into hydroxyl group-containing cyclic alkyl groups and hydroxyl group-containing chain alkyl groups.

In the case where the structural unit (a220 ′) is a structural unit having a hydroxyl group-containing cyclic alkyl group (hereinafter abbreviated as the structural unit (a221 ′)), the swelling suppression effect of the resist pattern is enhanced.
Also, the resolution is improved. Furthermore, good contrast and etching resistance are easily obtained.
The structural unit (a221 ′) is exemplified in the description of “structural unit (a22 ′) derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group” constituting the resin (A2 ′) described later, for example. Among the structural units, an aliphatic cyclic group is a saturated hydrocarbon group. Among them, the substituent bonded to the α-position of the acrylate ester is more preferably a fluorine atom or a fluorinated alkyl group, particularly preferably a fluorinated alkyl group, and a trifluoromethyl group (—CF ₃ ) is most preferred.

In the case where the structural unit (a220 ′) is a structural unit having a hydroxyl group-containing chain alkyl group (hereinafter abbreviated as “structural unit (a222 ′)”), the hydrophilicity of the entire component (A ′) is increased and an alkaline developer. Solubility in the water is increased and resolution is improved. Further, the controllability of the crosslinking reaction during the formation of the resist pattern becomes good, and the pattern shape and resolution are improved. Furthermore, there is a tendency that the film density is improved, and this can suppress the film loss during etching, and the heat resistance tends to be improved.
As the structural unit (a222 ′), for example, “structural unit (a23 derived from acrylic acid having no cyclic structure and having an alcoholic hydroxyl group in the side chain) constituting a resin (A2 ′) described later. Among the structural units exemplified in the description of “)”, those having a hydroxyalkyl group are exemplified. Among them, those having a hydroxyalkyl group in the ester portion of the acrylate ester are preferable, and among them, the substituent bonded to the α-position of the acrylate ester is more preferably a fluorine atom or a fluorinated alkyl group, Those that are fluorinated alkyl groups are particularly preferred, and those that are trifluoromethyl groups (—CF ₃ ) are most preferred.

As the structural unit (a220 ′), one type or a mixture of two or more types can be used.
10-80 mol% is preferable with respect to the sum total of all the structural units which comprise resin (A1 ') in resin (A1'), and the ratio of structural unit (a220 ') is more preferable 15-60 mol%. 20 to 55 mol% is more preferable. The effect by containing a structural unit (a220 ') is acquired by being more than the lower limit of the said range, and a balance with another structural unit becomes favorable by being below an upper limit.

When the structural unit (a220 ′) includes both the structural unit (a221 ′) and the structural unit (a222 ′), the mixing ratio of both is a molar ratio, and the structural unit (a221 ′): structural unit (a222) ') = 9: 1 to 1: 9 is preferable, 8: 2 to 2: 8 is more preferable, and 6: 4 to 7: 3 is more preferable.
A good exposure margin can be obtained by blending the structural unit (a221 ′) and the structural unit (a222 ′) in a balanced manner at the mixing ratio. Moreover, a moderate contrast is obtained and the resolution is improved. Furthermore, etching resistance is also improved.

Other structural units In the negative resist composition used as the second chemically amplified resist composition, the resin (A1 ′) is a structural unit other than the structural units (a1 ′) and (a2 ′). The structural unit used in the known component (A ′) for conventional chemically amplified resist compositions can be appropriately used.
In the present invention, the resin (A1 ′) is preferably a resin mainly composed of the structural unit (a1 ′) and the structural unit (a2 ′).
Here, the “main component” means that the total of the structural unit (a1 ′) and the structural unit (a2 ′) is 70 mol% or more with respect to the total of all the structural units constituting the resin (A1 ′). Means 80% by mole or more. Among them, a resin composed of the structural unit (a1 ′) and the structural unit (a2 ′) is preferable.

  In the present invention, the combination of the structural unit (a1 ′) and the structural unit (a2 ′) in the resin (A1 ′) is preferably a combination of the structural unit (a1 ′) and the structural unit (a210 ′). Examples of the combination include the following chemical formulas (A1′-1) to (A1′-4).

The mass average molecular weight (Mw; polystyrene-converted value by gel permeation chromatography) of the resin (A1 ′) is preferably 2000 to 10,000, more preferably 3000 to 6000, and particularly preferably 3000 to 5000. . A favorable contrast can be obtained by being more than the lower limit of the said range, and swelling of a resist pattern can be suppressed by being below an upper limit. As a result, the resolution is improved. Further, since the swelling of the pattern can be suppressed, the effect of improving the depth of focus (DOF) characteristic and the effect of suppressing the line edge roughness (LER) can be obtained. Moreover, it is preferable to make the said mass mean molecular weight into this range from the point that the swelling inhibitory effect of a resist pattern is also high. When the mass average molecular weight is lower within this range, good characteristics tend to be obtained.
The dispersity (Mw / Mn) is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5.

When the resin (A1 ′) is used in the component (A ′), one or more of the resins (A1 ′) can be mixed and used.
When the resin (A1 ′) is used, the ratio of the resin (A1 ′) contained in the component (A ′) is preferably 70% by mass or more, more preferably 80% by mass or more, and 100% by mass. % Is most preferred.

[Resin (A2 ′)]
The resin (A2 ′) has a structural unit (a21 ′) containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group.
In addition to the structural unit (a21 ′), the resin (A2 ′) preferably further includes a structural unit (a22 ′) derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group.
In addition to the structural unit (a21 ′) or the structural unit (a21 ′) and the structural unit (a22 ′), the resin (A2 ′) preferably further does not have a cyclic structure. And a structural unit (a23 ′) derived from acrylic acid having an alcoholic hydroxyl group in the side chain.

・ Structural unit (a21 ′)
The structural unit (a21 ′) is a structural unit containing an aliphatic cyclic group having a fluorinated hydroxyalkyl group. By including the structural unit (a21 ′), the solubility in the antkari developer is improved. Further, the swelling of the resist is suppressed, and the lithography properties such as the pattern shape and LWR are improved.

The aliphatic cyclic group having a fluorinated hydroxyalkyl group is the same as that of the structural unit (a1 ′), and the aliphatic cyclic group (the state before the fluorinated hydroxyalkyl group is bonded). Among them, a group in which two hydrogen atoms are removed from cyclohexane, adamantane, norbornane, or tetracyclododecane is preferable because it is easily available on the industry.
Of these exemplified monocyclic groups and polycyclic groups, groups in which two hydrogen atoms have been removed from norbornane are particularly preferred.

  The structural unit (a21 ′) is preferably a structural unit derived from acrylic acid, and in particular, an oxygen atom (—O—) of a carbonyloxy group [—C (═O) —O—] of an acrylate ester. And a structure in which the aliphatic cyclic group is bonded to each other (a structure in which a hydrogen atom of a carboxy group of acrylic acid is substituted with the aliphatic cyclic group).

  More specifically, the structural unit (a21 ′) is preferably a structural unit represented by the following general formula (1).

[Wherein, R represents a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms, or a halogenated lower alkyl group having 1 to 5 carbon atoms; y, t, and x are each independently an integer of 1 to 5; is there. ]

In formula (1), R is a hydrogen atom, a lower alkyl group having 1 to 5 carbon atoms, or a halogenated lower alkyl group having 1 to 5 carbon atoms.
Examples of the lower alkyl group for R include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. preferable.
The halogenated alkyl group for R is a group in which one or more hydrogen atoms of a lower alkyl group having 5 or less carbon atoms are substituted with a halogen atom. Specific examples of the lower alkyl group are the same as described above. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. The hydrogen atom substituted with a halogen atom may be a part or all of the hydrogen atoms constituting the alkyl group.
In the present invention, R is preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom or a methyl group in terms of industrial availability.

y is each independently an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.
t is an integer of 1 to 5, preferably an integer of 1 to 3, and 1 is most preferable.
x is an integer of 1 to 3, preferably an integer of 1 to 2, and 1 is most preferable.
In the structural unit represented by the general formula (1), it is preferable that a 2-norbornyl group or a 3-norbornyl group is bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a21 ′), one type or a mixture of two or more types can be used.
In the resin (A2 ′), the proportion of the structural unit (a21 ′) is preferably 10 to 90 mol% and more preferably 20 to 90 mol% with respect to the total of all the structural units constituting the resin (A2 ′). 40 to 90 mol% is particularly preferable, and 45 to 85 mol% is most preferable. The effect by containing a structural unit (a21 ') is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

・ Structural unit (a22 ′)
In addition to the structural unit (a21 ′), the resin (A2 ′) preferably further includes a structural unit (a22 ′) derived from an acrylate ester containing a hydroxyl group-containing aliphatic cyclic group. When the resin (A2 ′) having such a structural unit (a22 ′) is added to the negative resist composition, the hydroxyl group (alcoholic hydroxyl group) of the structural unit (a22 ′) is an acid generated from the component (B ′). By the action, it reacts with the component (C ′), whereby the resin (A2 ′) changes from a soluble property to an insoluble property in an alkaline developer.

The “hydroxyl group-containing aliphatic cyclic group” is a group in which a hydroxyl group is bonded to an aliphatic cyclic group.
The number of hydroxyl groups bonded to the aliphatic cyclic group is preferably 1 to 3, more preferably 1.
The aliphatic cyclic group may be monocyclic or polycyclic, but is preferably a polycyclic group. Moreover, it is preferable that it is an alicyclic hydrocarbon group. Moreover, it is preferable that it is saturated. Moreover, it is preferable that carbon number of an aliphatic cyclic group is 5-15.
Specific examples of the aliphatic cyclic group (the state before the hydroxyl group is bonded) include those similar to the aliphatic cyclic group of the structural unit (a21 ′).
As the aliphatic cyclic group of the structural unit (a22 ′), among them, a cyclohexyl group, an adamantyl group, a norbornyl group, and a tetracyclododecyl group are preferable because they are industrially available. Among these, a cyclohexyl group and an adamantyl group are preferable, and an adamantyl group is particularly preferable.
In addition to the hydroxyl group, a linear or branched alkyl group having 1 to 4 carbon atoms may be bonded to the aliphatic cyclic group.

In the structural unit (a22 ′), the hydroxyl group-containing aliphatic cyclic group is preferably bonded to the ester group (—C (═O) —O—) of the acrylate ester.
In this case, in the structural unit (a22 ′), another substituent may be bonded to the α-position (α-position carbon atom) of the acrylate ester instead of the hydrogen atom. Preferred examples of the substituent include an alkyl group and a halogenated alkyl group.
These descriptions are the same as the description of R in the general formula (1) of the structural unit (a21 ′), and among those capable of bonding to the α-position, a preferable one is a hydrogen atom or an alkyl group, In particular, a hydrogen atom or a methyl group is more preferable, and a hydrogen atom is most preferable.

  As a specific example of the structural unit (a22 ′), for example, a structural unit represented by the following general formula (2) is preferable.

[Wherein, R is as defined above; R ⁷ ″ is a hydrogen atom, an alkyl group, or an alkoxy group having 1 to 5 carbon atoms; and r ′ is an integer of 1 to 3].

In the formula (2), R is the same as the description of R in the general formula (1).
The alkyl group for R ⁷ ″ is preferably a lower alkyl group having 1 to 5 carbon atoms, and is the same as the lower alkyl group for R.
In the general formula (2), R and R ⁷ ″ are most preferably a hydrogen atom.
r ′ is an integer of 1 to 3, and is preferably 1.
The bonding position of the hydroxyl group is not particularly limited, but is preferably bonded to the 3rd position of the adamantyl group.

As the structural unit (a22 ′), one type or a mixture of two or more types can be used.
In the resin (A2 ′), the proportion of the structural unit (a22 ′) is preferably 10 to 70 mol%, more preferably 10 to 50 mol%, based on the total of all the structural units constituting the resin (A2 ′). 20-40 mol% is more preferable. The effect by containing a structural unit (a22 ') is acquired by being more than the lower limit of the said range, and a balance with another structural unit is favorable by being below an upper limit.

・ Structural unit (a23 ′)
In addition to the structural unit (a21 ′) or the structural unit (a21 ′) and the structural unit (a22 ′), the resin (A2 ′) further has no cyclic structure and has a side chain. It is preferable to have a structural unit (a23 ′) derived from acrylic acid having an alcoholic hydroxyl group.
When the resin (A2 ′) containing the structural unit (a23 ′) is blended with the negative resist composition, the alcoholic hydroxyl group of the structural unit (a23 ′), together with the hydroxyl group of the structural unit (a22 ′), (B ′) It reacts with the component (C ′) by the action of an acid generated from the component. Therefore, the resin (A2 ′) easily changes from a soluble property to an insoluble property with respect to an alkaline developer, and an effect of improving lithography properties such as resolution can be obtained. Moreover, film loss can be suppressed. Moreover, the controllability of the crosslinking reaction during pattern formation is improved. Furthermore, the film density tends to improve. Thereby, there exists a tendency for heat resistance to improve. Furthermore, etching resistance is also improved.

In the structural unit (a23 ′), “having no cyclic structure” means having no aliphatic cyclic group or aromatic group.
The structural unit (a23 ′) is clearly distinguished from the structural unit (a22 ′) by not having a cyclic structure.
Examples of the structural unit having an alcoholic hydroxyl group in the side chain include a structural unit having a hydroxyalkyl group.
Examples of the hydroxyalkyl group include those similar to the hydroxyalkyl group in the “fluorinated hydroxyalkyl group” of the structural unit (a21 ′).
For example, the hydroxyalkyl group may be directly bonded to the α-position carbon atom of the main chain (the portion where the ethylenic double bond of acrylic acid is cleaved), or may be substituted with the hydrogen atom of the carboxy group of acrylic acid. You may comprise ester.
In the structural unit (a23 ′), it is preferable that at least one or both of them be present.
When a hydroxyalkyl group is not bonded to the α-position, an alkyl group or a halogenated alkyl group may be bonded to the α-position carbon atom instead of a hydrogen atom. About these, it is the same as that of description of R in General formula (1).

  As the structural unit (23 ′), structural unit (a23 ′) represented by general formula (3) shown below is preferred.

[Wherein R ⁸ ″ represents a hydrogen atom, an alkyl group, a halogenated alkyl group, or a hydroxyalkyl group, R ⁹ ″ represents a hydrogen atom, an alkyl group, or a hydroxyalkyl group, and R ⁸ ″, R ^At least one of ⁹ "is a hydroxyalkyl group. ]

The hydroxyalkyl group in R ⁸ ″ is preferably a hydroxyalkyl group having 10 or less carbon atoms, desirably a linear or branched chain, and more preferably a hydroxyalkyl group having 2 to 8 carbon atoms. And most preferably a hydroxymethyl group or a hydroxyethyl group.
The number of hydroxyl groups and the bonding position are not particularly limited, but are usually one and preferably bonded to the terminal of the alkyl group.
The alkyl group for R ⁸ ″ is preferably an alkyl group having 10 or less carbon atoms, more preferably an alkyl group having 2 to 8 carbon atoms, and most preferably an ethyl group or a methyl group.
The halogenated alkyl group for R ⁸ ″ is preferably a group in which part or all of the hydrogen atoms in a lower alkyl group having 5 or less carbon atoms (preferably an ethyl group or a methyl group) 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.
As the alkyl group and hydroxyalkyl group for R ⁹ ″, the same alkyl groups and hydroxyalkyl groups as described for R ⁸ ″ can be used.

As the structural unit represented by the general formula (3), specifically, a structural unit derived from (α-hydroxyalkyl) acrylic acid (however, a structural unit derived from an acrylate ester is not included here). ), Structural units derived from (α-hydroxyalkyl) acrylic acid alkyl esters, and structural units derived from (α-alkyl) acrylic acid hydroxyalkyl esters.
Among these, when the structural unit (a23 ′) includes a structural unit derived from (α-hydroxyalkyl) acrylic acid alkyl ester, it is preferable from the viewpoint of improving the film density, and among them, (α-hydroxymethyl)- Structural units derived from acrylic acid ethyl ester or (α-hydroxymethyl) -acrylic acid methyl ester are preferred.
Moreover, when the structural unit (a23 ′) includes a structural unit derived from (α-alkyl) acrylic acid hydroxyalkyl ester, it is preferable in terms of crosslinking efficiency. Among them, a structural unit derived from α-methyl-acrylic acid hydroxyethyl ester or α-methyl-acrylic acid hydroxymethyl ester is preferable.

As the structural unit (a23 ′), one type or a mixture of two or more types can be used.
In the resin (A2 ′), the proportion of the structural unit (a23 ′) is preferably 5 to 50 mol% and more preferably 5 to 40 mol% with respect to the total of all the structural units constituting the resin (A2 ′). 5 to 30 mol% is particularly preferable, and 10 to 25 mol% is most preferable. The effect by containing a structural unit (a23 ') is acquired by being more than the lower limit of the said range, and a balance with another structural unit becomes favorable by being below an upper limit.

-Other structural unit Resin (A2 ') may have another structural unit which can be copolymerized as structural units other than said each structural unit (a21')-(a23 ').
As such a constitutional unit, a constitutional unit conventionally used for a resin component known for a chemically amplified resist composition can be used. For example, it is derived from an acrylate ester containing a lactone-containing monocyclic or polycyclic group. And a structural unit (a24 ′).
As the structural unit (a24 ′), the same structural units as those exemplified in the description of the structural unit (a2) in the component (A) of the positive resist composition can be given.

As the structural unit (a24 ′), one type or a mixture of two or more types can be used.
When the structural unit (a24 ′) is contained in the resin (A2 ′), the proportion of the structural unit (a24 ′) in the resin (A2 ′) is based on the total of all the structural units constituting the resin (A2 ′). 10 to 70 mol% is preferable, 10 to 40 mol% is more preferable, and 10 to 25 mol% is most preferable. The effect by containing a structural unit (a24 ') is acquired by being more than the lower limit of the said range, and a balance with another structural unit becomes favorable by being below an upper limit.

The resin (A2 ′) is particularly preferably a resin mainly composed of the structural units (a21 ′) to (a23 ′).
Here, the “main component” means that the total of the structural units (a21 ′) to (a23 ′) occupies 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol%. That's it. Most preferably, it is 100 mol%. That is, the resin (A2 ′) is most preferably a resin composed of the structural unit (a21 ′), the structural unit (a22 ′), and the structural unit (a23 ′).

The mass average molecular weight (Mw; polystyrene conversion value by gel permeation chromatography) of the resin (A2 ′) is preferably 2000 to 30000, more preferably 2000 to 10000, and further preferably 3000 to 8000. By setting it within this range, a good dissolution rate in an alkali developer can be obtained, which is preferable from the viewpoint of high resolution. When the mass average molecular weight is lower within this range, good characteristics tend to be obtained.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, and more preferably 1.0 to 2.5.

In the component (A ′), when the resin (A2 ′) is used, one or more of the resins (A2 ′) can be mixed and used.
When the resin (A2 ′) is used, the ratio of the resin (A2 ′) contained in the component (A ′) is preferably 50% by mass or more, more preferably 70% by mass or more, and 80% by mass. % Or more is particularly preferable, and 100% by mass is most preferable.

[Resin (A3 ′)]
The resin (A3 ′) has a structural unit (a31 ′) derived from hydroxystyrene.
In addition to the structural unit (a31 ′), the resin (A1 ′) preferably further includes a structural unit (a32 ′) derived from styrene.

[Structural unit (a31 ′)]
The structural unit (a31 ′) is a structural unit derived from hydroxystyrene. By including the structural unit (a31 ′) in the resin (A3 ′), dry etching resistance is improved. Furthermore, the structural unit (a31 ′) also has an advantage that the raw material hydroxystyrene is easily available and is inexpensive.
In the present specification and claims, the term “hydroxystyrene” refers to hydroxystyrene, and those obtained by replacing the hydrogen atom at the α-position of hydroxystyrene with another substituent such as an alkyl group, and derivatives thereof. Include concepts.
The α-position (α-position carbon atom) is a carbon atom to which a benzene ring is bonded unless otherwise specified.
The “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
Preferable examples of the structural unit (a31 ′) include structural units represented by general formula (a31′-1) shown below.

[In the formula (a31′-1), R ′ represents a hydrogen atom or a lower alkyl group; R ⁶ represents a lower alkyl group; p represents an integer of 1 to 3; q represents an integer of 0 to 2] . ]

In the general formula (a31′-1), the lower alkyl group for R ′ is an alkyl group having 1 to 5 carbon atoms, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, and n-butyl. Groups, isobutyl groups, tert-butyl groups, pentyl groups, isopentyl groups, neopentyl groups and the like include linear or branched alkyl groups, and among these, methyl groups are preferred.
R ′ is preferably a hydrogen atom or a lower alkyl group, particularly preferably a hydrogen atom or a methyl group.

p is an integer of 1 to 3, preferably 1.
The bonding position of the hydroxyl group may be any of the o-position, m-position and p-position of the phenyl group. When p is 1, the p-position is preferred because it is readily available and inexpensive. When p is 2 or 3, arbitrary substitution positions can be combined.

q is an integer of 0-2. Among these, q is preferably 0 or 1, and is preferably 0 industrially.
As the lower alkyl group for R ^{6, the same as} the lower alkyl group for R ′ can be exemplified.
When q is 1, the substitution position of R ⁶ may be any of the o-position, m-position, and p-position. When q is 2, arbitrary substitution positions can be combined. The plurality of R ⁶ may be the same or different.

As the structural unit (a31′-1), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.
The proportion of the structural unit (a31′-1) in the resin (A3 ′) is preferably 50 to 90 mol% with respect to the total of all the structural units constituting the resin (A3 ′), and is 55 to 85 mol. % Is more preferable, and 60 to 80 mol% is further more preferable. Within this range, moderate alkali solubility is obtained, and the balance with other structural units is good.

[Structural unit (a32 ′)]
The structural unit (a32 ′) is a structural unit derived from styrene. By having the structural unit (a32 ′), the solubility in an alkali developer can be adjusted. Moreover, when it is set as a resist composition, heat resistance and dry etching resistance improve.
In the present specification and claims, “styrene” means styrene, and those obtained by substituting the hydrogen atom at the α-position of styrene with another substituent such as an alkyl group, and derivatives thereof (provided that The concept includes hydroxystyrene. Therefore, the hydrogen atom of a phenyl group shall include what was substituted by substituents, such as a C1-C5 alkyl group.
“Structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.

  The proportion of the structural unit (a32 ′) in the resin (A3 ′) is preferably 1 to 40 mol%, more preferably 3 to 30 mol%, based on the total of all structural units constituting the resin (A3 ′). 5-25 mol% is more preferable. When it is at least the lower limit of the range, the effect of having the structural unit (a32 ') is high, and when it is at most the upper limit, the balance with other structural units is also good.

In the component (A ′), when the resin (A3 ′) is used, one or more of the resins (A3 ′) can be mixed and used.
When the resin (A3 ′) is used, the ratio of the resin (A3 ′) contained in the component (A ′) is preferably 50% by mass or more, more preferably 75% by mass or more, and 100% by mass. % Is most preferred.

The component (A ′) such as the resin (A1 ′), the resin (A2 ′), the resin (A3 ′) is, for example, a method in which a monomer for deriving each structural unit is radical-polymerized by a conventional method, International Publication No. 2004/076495. It can be synthesized by the method described in the pamphlet.
In addition to the resin (A1 ′), the resin (A2 ′), and the resin (A3 ′), the component (A ′) includes other polymer compounds (novolac resin, used in a conventional negative resist composition). An acrylic resin etc.) can also be used.

  The content of the (A ′) component in the negative resist composition may be adjusted according to the resist film thickness to be formed.

[(B ′) component]
The acid generator component (B ′) is not particularly limited, and any conventionally known acid generator for chemically amplified resists can be appropriately selected and used.
Examples of the component (B ′) include those exemplified in the description of the component (B) of the positive resist composition.
As the component (B ′), one type of acid generator may be used alone, or two or more types may be used in combination.
The content of the component (B ′) in the negative resist composition of the present invention is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A ′). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

[(C ′) component]
The crosslinking agent component (C ′) is not particularly limited, and can be arbitrarily selected from the crosslinking agents used in the chemically amplified negative resist compositions known so far.
Specifically, for example, 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis (hydroxymethyl) norbornane, cyclohexanedimethanol, 3,4,8 (or 9) -trihydroxytri Aliphatic cyclic carbonization having a hydroxyl group or a hydroxyalkyl group or both such as cyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, 1,3,5-trihydroxycyclohexane Examples thereof include hydrogen and oxygen-containing derivatives thereof.

In addition, amino group-containing compounds such as melamine, acetoguanamine, benzoguanamine, urea, ethylene urea, propylene urea, glycoluril are reacted with formaldehyde or formaldehyde and lower alcohol, and the hydrogen atom of the amino group is hydroxymethyl group or lower alkoxymethyl. And a compound substituted with a group and a compound having an epoxy group.
Of these, those using melamine are melamine-based crosslinking agents, those using urea are urea-based crosslinking agents, those using alkylene ureas such as ethylene urea and propylene urea are alkylene urea-based crosslinking agents, and glycoluril is used. What was used was a glycoluril-based crosslinking agent, and what used a compound having an epoxy group was called an epoxy-based crosslinking agent.
The component (C ′) is preferably at least one selected from the group consisting of melamine crosslinking agents, urea crosslinking agents, alkylene urea crosslinking agents, glycoluril crosslinking agents, and epoxy crosslinking agents, A glycoluril-based crosslinking agent is particularly preferable.

  Melamine-based crosslinking agents include compounds in which melamine and formaldehyde are reacted to replace the amino group hydrogen atom with a hydroxymethyl group, and melamine, formaldehyde and lower alcohol are reacted to convert the amino group hydrogen atom into a lower alkoxy group. Examples include compounds substituted with a methyl group. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxybutyl melamine, and the like, among which hexamethoxymethyl melamine is preferable.

  Urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to replace amino group hydrogen atoms with hydroxymethyl groups, and urea, formaldehyde and lower alcohols are reacted to convert amino group hydrogen atoms into lower alkoxy groups. Examples include compounds substituted with a methyl group. Specific examples include bismethoxymethylurea, bisethoxymethylurea, bispropoxymethylurea, bisbutoxymethylurea, etc. Among them, bismethoxymethylurea is preferable.

  As an alkylene urea type crosslinking agent, the compound represented, for example by the following general formula (c1'-1) is mentioned.

[In the formula, R ⁵ ′ and R ⁶ ′ are each independently a hydroxyl group or a lower alkoxy group, R ³ ′ and R ⁴ ′ are each independently a hydrogen atom, a hydroxyl group or a lower alkoxy group, and v is 0 or 1 It is an integer of ~ 2. ]

When R ⁵ ′ and R ⁶ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ⁵ ′ and R ⁶ ′ may be the same or different from each other. More preferably, they are the same.
When R ³ ′ and R ⁴ ′ are lower alkoxy groups, they are preferably alkoxy groups having 1 to 4 carbon atoms, and may be linear or branched. R ³ ′ and R ⁴ ′ may be the same or different from each other. More preferably, they are the same.
v is 0 or an integer of 1 to 2, preferably 0 or 1.
As the alkylene urea crosslinking agent, a compound in which v is 0 (ethylene urea crosslinking agent) and / or a compound in which v is 1 (propylene urea crosslinking agent) are particularly preferable.

  The compound represented by the general formula (c1′-1) can be obtained by a condensation reaction between alkylene urea and formalin, and by reacting this product with a lower alcohol.

  Specific examples of the alkylene urea crosslinking agent include, for example, mono and / or dihydroxymethylated ethylene urea, mono and / or dimethoxymethylated ethylene urea, mono and / or diethoxymethylated ethylene urea, mono and / or dipropoxy Ethylene urea-based crosslinking agents such as methylated ethylene urea, mono and / or dibutoxymethylated ethylene urea; mono and / or dihydroxymethylated propylene urea, mono and / or dimethoxymethylated propylene urea, mono and / or diethoxymethyl Propylene urea-based crosslinkers such as propylene urea, mono and / or dipropoxymethylated propylene urea, mono and / or dibutoxymethylated propylene urea; 1,3-di (methoxymethyl) 4,5-dihydroxy-2- Imidazolidinone, 1,3-di (Metoki Like, etc.) -4,5-dimethoxy-2-imidazolidinone.

Examples of the glycoluril-based crosslinking agent include glycoluril derivatives in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms. Such glycoluril derivatives can be obtained by condensation reaction of glycoluril and formalin, and by reacting this product with a lower alcohol.
Specific examples of the glycoluril-based crosslinking agent include, for example, mono, di, tri and / or tetrahydroxymethylated glycoluril, mono, di, tri and / or tetramethoxymethylated glycoluril, mono, di, tri and / or Examples include tetraethoxymethylated glycoluril, mono, di, tri and / or tetrapropoxymethylated glycoluril, mono, di, tri and / or tetrabutoxymethylated glycoluril.

The epoxy-based crosslinking agent is not particularly limited as long as it has an epoxy group, and can be arbitrarily selected and used. Among them, those having two or more epoxy groups are preferable. By having two or more epoxy groups, crosslinking reactivity is improved.
The number of epoxy groups is preferably 2 or more, more preferably 2 to 4, and most preferably 2.
The following are suitable as the epoxy-based crosslinking agent.

As the component (C ′), one type may be used alone, or two or more types may be used in combination.
The content of the component (C ′) is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the component (A ′), more preferably 3 to 30 parts by mass, further preferably 3 to 15 parts by mass, 5 to 10 parts by mass is most preferable. When the content of the component (C ′) is at least the lower limit value, crosslinking formation proceeds sufficiently and a good resist pattern with little swelling is obtained. Moreover, when it is less than or equal to this upper limit value, the storage stability of the resist coating solution is good and the deterioration of sensitivity over time is suppressed.

[Optional ingredients]
The negative resist composition further contains a nitrogen-containing organic compound component (D ′) (hereinafter referred to as “(D ′) component”) as an optional component in order to improve the resist pattern shape, stability with time, and the like. It is preferable to contain.
Examples of the component (D ′) include those exemplified in the description of the component (D) of the positive resist composition.
As the component (D ′), one type may be used alone, or two or more types may be used in combination.
The component (D ′) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A ′).

The negative resist composition includes a group consisting of organic carboxylic acid, phosphorus oxo acid and derivatives thereof as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape and stability with time. At least one compound (E ′) selected from (hereinafter referred to as “component (E ′)”) can be contained.
Examples of the component (E ′) include the same components as those exemplified in the description of the component (E) of the positive resist composition.
As the component (E ′), one type may be used alone, or two or more types may be used in combination.
The component (E ′) is usually used at a ratio of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A ′).

  The negative resist composition further includes miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coatability, dissolution inhibitors, plasticizers, Stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

[(S ′) component]
Examples of the component (S ′) include the same components as those exemplified in the description of the component (S) of the positive resist composition.
In the present invention, in particular, as the component (S ′), in addition to dissolving each component of the negative resist composition, an organic solvent that does not dissolve the first resist film (hereinafter referred to as “(S ₂ ′) component”) It is preferable to contain.
When the component (S) contains the component (S ₂ ′), the first resist pattern is formed when the chemically amplified negative resist composition is applied onto the support on which the first resist pattern is formed. The shape is kept good and the resist pattern can be formed stably.
Examples of such organic solvents (S ₂ '), are the same as those for the chemical amplification type positive resist composition (S) organic solvents mentioned component (S _2).

(S ') A component may be used individually by 1 type and may use 2 or more types.
The amount of component (S ′) used is not particularly limited, and the amount of the negative resist composition used is a liquid having a concentration that can be applied onto the support on which the first resist pattern is formed.

  EXAMPLES Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

[Preparation Example of First Chemically Amplified Resist Composition (Positive Resist Composition)]
Components shown in Table 1 below were mixed and dissolved to prepare a first chemically amplified resist composition (positive resist composition).

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1: A copolymer having a mass average molecular weight (Mw) of 7000 and a dispersity of 1.7 represented by the following chemical formula (A) -1. In the formula, the numerical value on the lower right of () indicates the ratio (mol%) of the structural unit to which the numerical value is given, and is a1: a2: a3 = 45: 35: 20.
(A) -2: a copolymer having a mass average molecular weight (Mw) of 7000 and a dispersity of 1.7 represented by the following chemical formula (A) -2. In the formula, the numerical value on the lower right of () indicates the ratio (mol%) of the structural unit to which the numerical value is attached, and is a1: a2: a3 = 35: 45: 20.
(A) -3: a copolymer having a mass average molecular weight (Mw) of 7000 and a dispersity of 1.7 represented by the following chemical formula (A) -3. In the formula, the numerical value on the lower right of () indicates the ratio (mol%) of the structural unit to which the numerical value is attached, and is a1: a2: a3 = 40: 40: 20.
(B) -1: (4-methylphenyl) diphenylsulfonium nonafluoro-n-butanesulfonate.
(D) -1: tri-n-pentylamine.
(E) -1: salicylic acid.
(S) -1: γ-butyrolactone.
(S) -2: Mixed solvent of PGMEA and PGME (PGMEA: PGME = 6: 4 (mass ratio).

[Examples of Preparation of Second Positive Type and Negative Type Resist Composition]
Components shown in Table 2 below were mixed and dissolved to prepare a second chemically amplified resist composition (positive resist composition, negative resist composition).

Each abbreviation in Table 2 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -4: a copolymer represented by the following chemical formula (A) -4 [Mw: 7000, dispersity: 1.5].
(A) -5: a copolymer represented by the following chemical formula (A) -5 [Mw: 7000, dispersity: 1.5].
(A ′)-1: a copolymer represented by the following chemical formula (A ′)-1 [Mw: 4700, dispersity: 1.48, manufactured by Promerus Corporation].
(A ′)-2: a copolymer represented by the following chemical formula (A ′)-2 [Mw: 3000, dispersity: 1.50].
(B) -2: A compound represented by the following formula (B) -2.
(B ′)-1: Triphenylsulfonium heptafluoro-n-propanesulfonate (B ′)-2: Compound represented by the following formula (B ′)-2 (C ′)-1: Tetraethoxymethylated glycoluril E-9401 (product name, manufactured by Sanwa Chemical Co., Ltd.).
(C ′)-2: tetramethoxymethylated glycoluril MX-270 (product name, manufactured by Sanwa Chemical Co., Ltd.).
(D) -2: Triethanolamine (D ′)-1: Triisopropanolamine.
(E ′)-1: malonic acid.
(S) -3: Isobutanol.
(S) -4: 1-butoxy-2-propanol

[Pattern formation]
Pattern formation was performed as in Examples 1 and 2 below. Note that the exposure table 3-6, because 5~50mJ / cm ² from 5 mJ / cm ^2, was carried waving exposure amount up to 50 mJ / cm ² over the steps for each 1 mJ / cm ² It shows that. [Example 1]
Tables 3 and 4 show the first and second resists used for pattern formation by ArF exposure, and the baking conditions applied to each resist. The pattern formation process is as follows.

[Example 1]
First, an organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thus, an organic antireflection film having a film thickness of 85 nm was formed.
A first chemically amplified resist composition (positive resist composition) shown in Table 3 is spin-coated on the organic antireflection film, and prebaking (PAB) treatment is performed on the hot plate under the conditions shown in Table 3. By performing and drying, a resist film (first resist film) having a film thickness shown in Table 3 was formed.
Next, for the first resist film, an ArF excimer laser (193 nm) is selected through a mask pattern using an ArF exposure apparatus NSR-S302A (Nikon Corporation; NA (numerical aperture) = 0.60). Irradiated. Thereafter, post-exposure heating (PEB) treatment was performed under the conditions shown in Table 3.
Subsequently, a second chemically amplified resist composition (positive composition or negative resist composition) shown in Table 4 is spin-coated on the first resist film, and the surface is displayed on a hot plate. A pre-bake (PAB) treatment was performed using the condition 4 and dried to form a resist film (second resist film) having a film thickness shown in Table 4.
Next, an ArF excimer laser (193 nm) is applied to the second resist film through a mask pattern using an ArF exposure apparatus NSR-S302A (Nikon Corporation; NA (numerical aperture) = 0.60). Selectively irradiated. At this time, the pattern was exposed to be orthogonal to the second resist film with respect to the pattern exposed to the first resist film.
Thereafter, PEB treatment was performed under the conditions shown in Table 4, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 30 seconds, followed by water rinsing with pure water for 30 seconds, Shake off and dry.
L / S derived from the second resist film on the line (70 to 1000 nm) of the L / S pattern formed in the first resist film for any of the examples by the resist pattern forming method as described above. The pattern lines (70 to 1000 nm) were formed so as to overlap perpendicularly.
A photograph of the resist pattern obtained in Example 1-2 is shown in FIG. As shown in FIG. 1, the space portion of the L / S pattern formed by the first resist film is not filled with the L / S pattern derived from the second resist film, and a clear space is ensured. I was able to. Moreover, it was confirmed that the same applies to other examples.

[Example 2]
Tables 5 and 6 show the first and second resists used for pattern formation by KrF exposure, and the baking conditions applied to each resist. The pattern formation process is as follows.
First, an organic antireflection film composition “DUV42” (trade name, manufactured by Nissan Chemical Industries, Ltd.) was applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to dry. As a result, an organic antireflection film having a film thickness of 65 nm was formed.
A first chemically amplified resist composition (positive resist composition) shown in Table 5 is spin-coated on the organic antireflection film, and prebaking (PAB) treatment is performed on the hot plate under the conditions shown in Table 5. By performing and drying, a resist film (first resist film) having a film thickness shown in Table 5 was formed.
Next, a KrF excimer laser (248 nm) is selected through the mask pattern for the first resist film using an ArF exposure apparatus NSR-S203C (Nikon Corporation; NA (numerical aperture) = 0.68). Irradiated. Thereafter, post-exposure heating (PEB) treatment was performed under the conditions shown in Table 5.
Subsequently, a second chemically amplified resist composition (negative resist composition) shown in Table 6 is spin-coated on the first resist film, and the conditions shown in Table 6 are used on a hot plate. The resist film (second resist film) having the film thickness shown in Table 6 was formed by performing pre-baking (PAB) treatment and drying.
Next, an ArF excimer laser (248 nm) is applied to the second resist film through a mask pattern using a KrF exposure apparatus NSR-S302C (Nikon Corporation; NA (numerical aperture) = 0.68). Selectively irradiated. At this time, the pattern was exposed to be orthogonal to the second resist film with respect to the pattern exposed to the first resist film.
Thereafter, PEB treatment was performed under the conditions shown in Table 6, followed by development with an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C. for 30 seconds, and then water rinsing with pure water for 30 seconds. Shake off and dry.
L / S derived from the second resist film on the line (150 to 1000 nm) of the L / S pattern formed in the first resist film for any of the examples by the resist pattern forming method described above. Pattern lines (120 to 1000 nm) were formed so as to overlap perpendicularly. At this time, the space portion of the L / S pattern formed by the first resist film was not filled with the L / S pattern derived from the second resist film, and a clear space could be secured.

  From the above results, by the resist pattern forming method of the present invention, a fine multilayer resist pattern having a complicated three-dimensional structure such as a hollow structure can be formed using a liquid resist such as a KrF resist or an ArF resist. It was confirmed.

Claims (10)

A first step of forming a first resist film using the first chemically amplified resist composition, and selectively exposing the first resist film;
A second chemically amplified resist composition is applied onto the first resist film to form a second resist film, the second resist film is selectively exposed, and a post-exposure bake treatment is performed. The second step,
Developing the first resist film and the second resist film to form a multilayer resist pattern,
A resist pattern forming method, wherein the first chemically amplified resist composition is a positive resist composition whose solubility in an alkali developer increases upon exposure.   The resist pattern forming method according to claim 1, further comprising a post-exposure baking process in the first step. The resist pattern forming method according to claim 2, wherein the temperature of the post-exposure bake treatment in the second step is the same as or lower than the temperature of the post-exposure bake treatment in the first step.   The resist pattern forming method according to claim 1, wherein the first chemically amplified resist composition contains a resin component having a structural unit derived from an acrylate ester.   The resist pattern forming method according to claim 1, wherein the second chemically amplified resist composition contains an organic solvent that does not dissolve the first resist film.   6. The resist pattern according to claim 5, wherein the organic solvent that does not dissolve the first resist film is at least one selected from the group consisting of alcohol solvents, fluorine solvents, and ether organic solvents having no hydroxyl group. Forming method.   In the second step, before the second resist film is selectively exposed, the second resist film is subjected to a pre-bake treatment, and the temperature of the pre-bake treatment is the same as that in the first step. The method for forming a resist pattern according to claim 1, wherein the temperature is the same as or lower than the temperature of the post-exposure baking process.   The resist pattern forming method according to claim 1, wherein the second chemically amplified resist composition is a positive resist composition whose solubility in an alkali developer increases upon exposure.     The resist pattern forming method according to claim 8, wherein the second chemically amplified resist composition contains a resin component having a structural unit derived from an acrylate ester.   The method for forming a resist pattern according to any one of claims 1 to 6, wherein the second chemically amplified resist composition is a negative resist composition whose solubility in an alkaline developer is reduced by exposure.