JPWO2019044510A1 - Pattern forming method, ion implantation method, laminate, kit, composition for forming resist underlayer film, resist composition, and method for manufacturing electronic device - Google Patents

Abstract

According to the present invention, (1) a step of forming a resist underlayer film on a substrate to be processed, and (2) a resin having an atom selected from the group consisting of (A) Si atom and Ti atom on the resist underlayer film. A step of forming a resist film with a resist composition containing: (3) a step of exposing the resist film, (4) a step of developing the exposed resist film to form a resist pattern, (5) And a step of forming a pattern by processing the resist underlayer film using the resist pattern as a mask, wherein the resist underlayer film has a film thickness of 2.5 μm or more and a resist film thickness of 1 μm. The following pattern forming method, an ion implantation method using the same, and a laminate, a kit, a resist underlayer film forming composition and a resist used in the pattern forming method. To provide a composition and an electronic device manufacturing method.

Description

  The present invention relates to a pattern forming method, an ion implantation method, a laminate, a kit, a composition for forming a resist underlayer film, a resist composition, and a method for manufacturing an electronic device. More specifically, the present invention relates to a pattern forming method and an ion implantation method suitable for a semiconductor manufacturing process such as an IC (Integrated Circuit), a circuit substrate such as a liquid crystal and a thermal head, and other lithography processes of photofabrication. The present invention relates to a method, a laminate, a kit, a composition for forming a resist underlayer film, a resist composition, and a method for producing an electronic device.

  BACKGROUND ART Conventionally, in a process of manufacturing a semiconductor device such as an IC, fine processing by lithography using a resist composition has been performed, and various pattern forming methods have been proposed.

Various resist compositions are known, and as one form, a composition containing a resin having a repeating unit having a Si atom is known.
For example, Patent Document 1 discloses (1) a step of forming a resist underlayer film on a substrate to be processed, (2) a resin having a repeating unit containing Si atoms (A) on the resist underlayer film, B) a step of forming a resist film with a resist composition containing a compound that generates an acid upon irradiation with actinic rays or radiation, (3) a step of exposing the resist film, and (4) an exposed resist film Developing a negative resist pattern using a developing solution containing an organic solvent, and (5) forming a pattern by processing the resist underlayer film and the substrate to be processed using the resist pattern as a mask. And a pattern forming method, wherein the content of the resin (A) is 20% by mass or more based on the total solid content of the resist composition.
Further, for example, Patent Document 2 discloses a silicon-containing polymer compound containing a specific repeating unit and used for a resist material.

International Publication No. WO 2016/208300 Japanese Patent Application Laid-Open No. 2002-256033

By the way, in manufacturing semiconductor devices, in a mode in which ions are implanted into a deep part of a substrate, ions are implanted into a substrate in which a specific region is masked by a resist pattern having a thick film thickness (eg, 2.5 μm or more). It is possible to do.
However, when a resist pattern having a large thickness and a high degree of fineness is to be formed by exposing and developing the resist film, a resist pattern having a vertically long cross section is used in the developing step. There was a problem that it was easy to fall down due to a capillary force from

  The present invention has been made in view of the above circumstances, and has a thick film thickness (for example, 2.5 μm or more) and a pattern forming method capable of forming a pattern in which pattern collapse hardly occurs. It is an object of the present invention to provide a laminate, a kit, a composition for forming a resist underlayer film, a resist composition, and a method for producing an electronic device, which are used in the ion implantation method and the pattern forming method.

  That is, the present inventors have found that the above problem can be solved by the following constitution.

[1]
(1) forming a resist underlayer film on a substrate to be processed;
(2) forming a resist film on the resist underlayer film by using a resist composition containing (A) a resin having an atom selected from the group consisting of Si atoms and Ti atoms;
(3) exposing the resist film to light;
(4) developing the exposed resist film to form a resist pattern;
(5) forming a pattern by processing the resist underlayer film using the resist pattern as a mask,
A pattern forming method, wherein the thickness of the resist underlayer film is 2.5 μm or more, and the thickness of the resist film is 1 μm or less.
[2]
The pattern forming method according to [1], wherein the resin (A) is a resin having a Si atom.
[3]
The pattern forming method according to [2], wherein the content of Si atoms in the resin (A) is 1 to 30% by mass based on the total amount of the resin (A).
[4]
The pattern forming method according to any one of [1] to [3], wherein the resin (A) has a repeating unit having an acid-decomposable group.
[5]
The pattern forming method according to any one of [1] to [4], wherein the resin (A) has at least one selected from the group consisting of a lactone structure, a sultone structure, and a carbonate structure.
[6]
The step (4) is a step of developing the exposed resist film with a developing solution to form a resist pattern, wherein the developing solution is an alkaline developing solution. Item 2. The pattern forming method according to Item 1.
[7]
The pattern forming method according to any one of [1] to [6], wherein in the step (3), the resist film is exposed by any one of KrF exposure, ArF exposure, and ArF immersion exposure.
[8]
The method according to any one of [1] to [7], wherein the step (5) is a step of forming a pattern by performing dry etching on the resist underlayer film using the resist pattern as a mask. Pattern formation method.
[9]
The pattern forming method according to [8], wherein the dry etching for the resist underlayer film is oxygen plasma etching.
[10]
The pattern forming method according to any one of [1] to [9], wherein the thickness of the resist underlayer film is 4 μm or more.
[11]
The pattern forming method according to any one of [1] to [10], wherein the resist composition is a chemically amplified resist composition.
[12]
An ion implantation method, wherein the pattern obtained by the pattern formation method according to any one of [1] to [11] is used as a mask to ion-implant the substrate to be processed.
[13]
A resist underlayer film and an atom selected from the group consisting of (A) Si atoms and Ti atoms are formed on a substrate to be processed, which is used in the pattern forming method according to any one of [1] to [11]. And a resist film formed of a resist composition containing a resin having the compound (B) and a compound capable of generating an acid upon irradiation with actinic rays or radiation.
[14]
A kit for use in the pattern forming method according to any one of [1] to [11], comprising a composition for forming a resist underlayer film for forming the resist underlayer film, and the resist composition.
[15]
A composition for forming a resist underlayer film included in the kit according to [14].
[16]
[14] A resist composition contained in the kit according to [14].
[17]
A composition for forming a resist underlayer film used in the pattern forming method according to any one of [1] to [11].
[18]
A resist composition used in the pattern forming method according to any one of [1] to [11].
[19]
A method for manufacturing an electronic device, comprising the pattern formation method according to any one of [1] to [11] or the ion implantation method according to [12].

  According to the present invention, a pattern forming method capable of forming a pattern having a large thickness (for example, 2.5 μm or more) and hardly causing pattern collapse, an ion implantation method using the same, and the pattern forming method The present invention can provide a laminate, a kit, a composition for forming a resist underlayer film, a resist composition, and a method for producing an electronic device used in the method.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In the description of groups and atomic groups in this specification, in the case where substitution or unsubstitution is not explicitly described, both those having no substituent and those having a substituent are included. For example, the term “alkyl group” that does not clearly indicate substitution or unsubstitution includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). It shall be.
In the present invention, the term "actinic ray" or "radiation" refers to, for example, the emission line spectrum of a mercury lamp, far ultraviolet represented by excimer laser, extreme ultraviolet (EUV light), X-ray, electron beam, ion beam, and other particle beams. Means In the present invention, “light” means actinic rays or radiation.
Unless otherwise specified, the term “exposure” in this specification means not only exposure using far ultraviolet rays such as mercury lamps and excimer lasers, X-rays, extreme ultraviolet rays (EUV light), but also electron beams and ion beams. It is assumed that drawing by a particle beam such as is also included.
In this specification, “(meth) acrylate” means “at least one of acrylate and methacrylate”. Further, “(meth) acrylic acid” means “at least one of acrylic acid and methacrylic acid”.
In this specification, the numerical range represented by using “to” means a range including the numerical values described before and after “to” as the lower limit and the upper limit.
In the present invention, “1「 ”is synonymous with“ 0.1 nanometer (nm) ”.

[Pattern forming method]
The pattern forming method of the present invention (hereinafter, also referred to as the method of the present invention)
(1) forming a resist underlayer film on a substrate to be processed;
(2) forming a resist film on the resist underlayer film by using a resist composition containing (A) a resin having an atom selected from the group consisting of Si atoms and Ti atoms;
(3) exposing the resist film to light;
(4) developing the exposed resist film to form a resist pattern;
(5) forming a pattern by processing the resist underlayer film using the resist pattern as a mask,
The thickness of the resist underlayer film is 2.5 μm or more, and the thickness of the resist film is 1 μm or less.

  Since the method of the present invention has such a configuration, it is considered that a desired effect can be obtained. The reason is not clear, but is presumed to be as follows.

First, the pattern (hereinafter, also referred to as “final pattern”) obtained after step (5) of the method of the present invention is a pattern formed by processing a resist underlayer film (hereinafter, also referred to as “resist underlayer film pattern”). ) On which a resist pattern is provided.
Here, since the film thickness of the resist underlayer film pattern is 2.5 μm or more, the final pattern including the film thickness of the resist underlayer film pattern also has a large film thickness. Thus, the present invention finally intends to form a pattern having a large film thickness.

As described above, the thickness of the resist film for forming the resist pattern is set to 1 μm or less. Since the upper limit of the thickness of the resist film is defined as described above, the thickness of the resist pattern formed by exposure and development is also limited to 1 μm or less. However, the resist pattern does not easily fall down.
Further, when processing the resist underlayer film using the resist pattern as a mask (that is, forming the resist underlayer film pattern), for example, by adopting a dry process such as a dry etching process, the obtained pattern can be a developing solution or the like. To avoid receiving a capillary force due to the liquid. Thereby, the resist underlayer film pattern can be made hard to fall down.
Further, the resist pattern obtained from the resist composition of the present invention contains a resin having an atom selected from the group consisting of Si atoms and Ti atoms. Here, since Si atoms and Ti atoms are atoms that impart high etching resistance to the resist pattern, an etching process is performed on the resist underlayer film using the resist pattern whose thickness is limited as described above as a mask. However, the resist underlayer film having a desired shape can be processed, for example, because the resist pattern as a mask remains as intended.
From the above, it is considered that the final pattern is a pattern that has a large thickness and is hard to fall down.

Hereinafter, each step of the pattern forming method of the present invention will be described.
[Step (1): Step of forming a resist underlayer film on a substrate to be processed]
The substrate to be processed in the step (1) may be provided on the underlayer.
The materials of the underlayer, the substrate to be processed, and the resist underlayer film are not particularly limited, but may be, for example, an inorganic substrate such as silicon, SiN, SiO ₂ or SiN, or an SOG (Spin on Glass) coating, respectively. A substrate generally used in a process for manufacturing a semiconductor such as an IC, a semiconductor substrate such as an IC, a circuit substrate such as a liquid crystal and a thermal head, and a lithography process for other photofabrication can be used.
In particular, a silicon (Si) substrate can be preferably used as the substrate to be processed.

Further, the substrate to be processed may be a stepped substrate. The step substrate is a substrate having at least one step formed on the substrate.
When the substrate to be processed is a stepped substrate, the thickness of the resist underlayer film means a height from a bottom surface on the step substrate to an upper surface of the formed resist underlayer film.
For example, in a mode in which ions are implanted into a substrate to be processed, a substrate in which fins and gates are patterned on a flat substrate can be used as the step substrate. When a resist underlayer film is applied on the stepped substrate on which the fins and gates are patterned as described above, the thickness of the resist underlayer film is defined as the height from the upper surface of the fin or gate to the upper surface of the resist underlayer film formed. Rather, it means the height from the bottom surface on the step substrate to the top surface of the resist underlayer film formed as described above.
The size (width, length, height, etc.), spacing, structure, configuration, and the like of the fins and gates are described in, for example, IEICE Vol. 91, No. 1, 200825-29, "Advanced FinFET Process and Integration Technology", Jpn. J. Appl. Phys. Vol. 42 (2003) pp. Part No. 4142-4146. 6B, June 2003 "Fin-Type Double-GateMetal-Oxide-Semiconductor Field-Effect Transistors Fabricated by Orientation-Dependent Exploration and Replenishment of the Appropriate Benefit of the Appropriate Benefit of the Orientation and the Dependency of the Employment and the Employment of the Exploitation to

As the step substrate, for example, the groove width is equal to or less than the exposure wavelength (preferably 100 nm or less, more preferably 40 nm or less, usually 15 nm or more), and the depth is 100 nm or less (preferably 50 to 100 nm, more preferably 65 to 100 nm). A stepped substrate having a groove of 100 nm), a diameter of not more than the exposure wavelength (preferably 100 nm or less, more preferably 40 nm or less, usually 15 nm or more), and a depth of 100 nm or less (preferably 50 to 100 nm, more preferably Stepped substrate having a cylindrical concave portion of 65 to 100 nm).
Examples of the stepped substrate having the above-mentioned groove portion include a stepped substrate having a plurality of grooves repeatedly at equal intervals, for example, at a pitch of 20 nm to 200 nm (preferably 50 to 150 nm, more preferably 70 to 120 nm).
Examples of the stepped substrate having the above-described cylindrical recessed portion include a stepped substrate having a plurality of cylindrical recessed portions, for example, having a pitch of 20 nm to 200 nm (preferably 50 to 150 nm, more preferably 70 to 120 nm) repeatedly at equal intervals. Is mentioned.

The resist underlayer film is required to have a function of improving the pattern resolution of the resist layer and a function of transferring the resist pattern onto the substrate to be processed while maintaining a good pattern shape. For example, SOC (Spin on Carbon) is required. ) Layers can be suitably mentioned.
Further, as the resist underlayer film, a crosslinked film can also be suitably exemplified. More specifically, a resin, a cross-linking agent, a photo-acid generator or a thermal acid generator, and a photo- or thermal cross-linking of a coating film obtained from a composition containing an additive that is added as necessary. Can also be suitably mentioned. As each component such as the resin, the crosslinking agent, the thermal acid generator, and the additive, for example, conventionally known materials can be appropriately used.
In the present invention, the thickness of the resist underlayer film is 2.5 μm or more, and since the thickness is large, if necessary, “formation of a coating film, and photocrosslinking or thermal crosslinking of the coating film” This may be performed a plurality of times so that the finally formed resist underlayer film has a thickness of 2.5 μm or more.
The formation of the substrate to be processed and the resist underlayer film can be performed by appropriately employing a well-known method according to the type of the material to be used.
When the substrate to be processed is formed on the underlayer, the method includes, on the underlayer, a liquid containing a material constituting the substrate to be processed, a conventionally known spin coating method, a spray method, a roller coating method, Examples include a method of applying and drying based on an immersion method, and a method of depositing a material constituting a substrate to be processed by a CVD method.
As a method of forming a resist underlayer film, a liquid containing a material constituting the resist underlayer film is applied on a substrate to be processed based on a conventionally known spin coating method, spraying method, roller coating method, dipping method, or the like. And a method of depositing a material constituting the resist underlayer film by a CVD method. The solid content concentration of the liquid containing the material constituting the resist underlayer film is preferably 10 to 55% by mass, more preferably 15 to 50% by mass, and further preferably 20 to 45% by mass. preferable.
The thickness of the resist underlayer film is at least 2.5 μm, preferably at least 4 μm. Further, the thickness of the resist underlayer film is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

  In the resist underlayer film used in the present invention, preferably, the function of improving the pattern resolution of the resist film, and the resist pattern formed on the upper layer is transferred onto the substrate to be processed in a state where the pattern shape is well maintained. Function is required. One of the functions to assist the pattern resolution of the resist film is to control the refractive index and extinction coefficient of the resist underlayer film at the exposure wavelength to appropriately control the reflection from the substrate side during exposure in the lithography process. And an optical function of maintaining an optical image formed at the time of exposure in a favorable shape. As other functions, the structure of the main chain and side chains of the resin, and the functional group of the cross-linking agent and other additives used together improve the interaction with the resist, and maintain the rectangular shape of the pattern cross section after development. And a function of assisting the resolution in the development process after exposure by the action of suppressing development defects such as pattern collapse, bridges, and pattern defects. Furthermore, when the pattern shape is transferred to the substrate to be processed, the resist film formed on the upper layer, and the resist lower layer film, when etching under conditions appropriately selected corresponding to the respective thickness and etching rate of the substrate to be processed. The etching mask also has a function of maintaining good mask performance.

  As a method of improving the reflection characteristics at the time of exposure, for example, in a mask exposure process, for example, a product based on exposure information including a mask pattern shape and transmittance, exposure intensity, deflection and shape of a projection light source, and the like. With the simulation software known under the name PROLITH (manufactured by KLATencor), the reflection characteristics are improved at the exposure wavelength, and as a result, the refractive index n value and the extinction of the underlayer film for maintaining the optical image at the time of exposure to a rectangular shape. By obtaining target design information such as the coefficient k value and the thickness of the underlayer film, and by using additives such as a resin structure and a cross-linking agent appropriate for the obtained target, good reflection characteristics and resolution can be obtained. Can be obtained. The resist underlayer film of the present invention is preferably designed in view of the above required properties. The preferable range of the refractive index n value of the lower layer film is preferably 1.2 or more and 3.0 or less. Further, the preferable range of the extinction coefficient k value of the lower layer film is preferably 0.05 or more and 1.0 or less.

As a method of improving the resolution by maintaining the rectangularity of the pattern cross section and suppressing development defects such as pattern collapse, bridges, and pattern defects, the mechanism is unknown, but the resist underlayer film and the resist film are not known. Interaction (intermolecular interaction), footing due to slight interfacial mixing between the resist film and the resist underlayer, and progression during development due to the relative movement of components between the resist underlayer and the resist film The resolution can be improved as a result by changing the reaction activity of the deprotection reaction of the protecting group by the acid to be formed and the dissolution of the polymer after the reaction in the developer. As the resin that can be used for the resist underlayer film, in view of the lithography performance and the processability of the substrate to be processed, by selecting a more appropriate resin, it is possible to obtain good resolution and processability. .
As another function, in a lithography process on a processed substrate, it is necessary to form a flat resist underlayer film on a substrate having a concavo-convex structure conforming to a pattern shape. There is also a function that satisfies the property.

<Resin for resist underlayer film>
As the resin that can be used for the resist underlayer film of the present invention (hereinafter, also referred to as “resin for the resist underlayer film”), as described above, for example, conventionally known materials can be appropriately used. It is preferable to arbitrarily design and use a composition using a polymer or a resin described below from the viewpoint of achieving a balance between resolution, defects, and processability of the substrate to be processed.
However, the resin for the resist underlayer film typically does not have an acid-decomposable group (specifically, an acid-decomposable group in the resin (A) described later).
As the resin for the resist underlayer film, (meth) acrylic resin, styrene resin, cellulose resin, phenol resin (novolak resin), and the like can be used. As other resins, an aromatic polyester resin, an aromatic polyimide resin, a polybenzoxazole resin, an aromatic polyamide resin, an acenaphthylene-based resin, an isocyanuric acid-based resin, or the like can be used.

In particular, as the aromatic polyamide resin and the aromatic polyimide resin, for example, resin compounds described in Japanese Patent No. 4120584, resin compounds described in Patent Nos. 4466877 [0021] to [0053], and Japanese Patent No. 4525940 [0025] To [0050] can be used. As the novolak resin, resin compounds described in Japanese Patent Nos. 5,215,825 [0015] to [0058] and No. 5,257,099 [0023] to [0041] can be used.
Examples of the acenaphthylene-based resin include, for example, resin compounds described in Japanese Patent Nos. 4666166 [0032] to [0052], resin compounds described in Japanese Patent Nos. 04388429 [0037] to [0043], and Japanese Patent No. 5040839 [0026] to [ 0065], resin compounds described in JP-A-4892670 [0015] to [0032], and the like.

The resin for a resist underlayer film is also preferably a resin containing a repeating unit containing a hydroxyl group that is a crosslinking reactive group.
Further, the resin for the resist underlayer film preferably also contains a repeating unit having a lactone structure, which will be described later in the resin (A).
The resin for the resist underlayer film can be formed by copolymerizing a non-crosslinkable monomer, whereby fine adjustment of the dry etching rate, the reflectance and the like can be performed. The following are mentioned as such a copolymerization monomer. For example, it has one addition-polymerizable unsaturated bond selected from acrylates, acrylamides, methacrylates, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, crotonates, and the like. Compound.

  Examples of the acrylates include alkyl acrylates having 1 to 10 carbon atoms in the alkyl group.

  Examples of the methacrylates include alkyl methacrylates in which the alkyl group has 1 to 10 carbon atoms.

  Examples of acrylamides include acrylamide, N-alkylacrylamide, N-arylacrylamide, N, N-dialkylacrylamide, N, N-diarylacrylamide, N-methyl-N-phenylacrylamide, N-2-acetamidoethyl-N- Acetylacrylamide and the like can be mentioned.

  Examples of methacrylamides include methacrylamide, N-alkyl methacrylamide, N-aryl methacrylamide, N, N-dialkyl methacrylamide, N, N-diaryl methacrylamide, N-methyl-N-phenyl methacrylamide, N- Ethyl-N-phenylmethacrylamide and the like.

  Examples of vinyl ethers include alkyl vinyl ether, vinyl aryl ether and the like.

  Examples of the vinyl esters include vinyl butyrate, vinyl isobutyrate, and vinyl trimethyl acetate.

  Examples of the styrenes include styrene, alkyl styrene, alkoxy styrene, and halogen styrene.

  Examples of crotonic esters include alkyl crotonates such as butyl crotonate, hexyl crotonate, and glycerin monocrotonate.

  In addition, dialkyl itaconates, dialkyl esters or monoalkyl esters of maleic acid or fumaric acid, crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilenitrile and the like can be mentioned. In addition, generally, any addition-polymerizable unsaturated compound that can be copolymerized with a polymer containing at least one hydroxyl group as a crosslinking reactive group per repeating unit can be used.

  The resin for the resist underlayer film may be any of a random polymer, a block polymer and a graft polymer. The polymer forming the resist underlayer film can be synthesized by a method such as radical polymerization, anionic polymerization, or cationic polymerization. Various forms such as solution polymerization, suspension polymerization, emulsion polymerization and bulk polymerization are possible.

  Further, as the resin for the resist underlayer film, various phenolic polymers having a phenol structure portion can be used. Preferably, a novolak resin, a p-hydroxystyrene homopolymer, an m-hydroxystyrene homopolymer, a copolymer having a p-hydroxystyrene structure, and a copolymer having an m-hydroxystyrene structure can be exemplified. In these copolymers, it is preferable that the copolymer has a repeating unit represented by the following general formula (1).

In the formula, R ₁ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a cyano group, or a halogen atom, and is preferably a hydrogen atom or a methyl group. L ₁ represents a single bond, —COO—, —CON (R ₃ ) —, or an arylene group, and R ₃ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. L ₁ is preferably a single bond, —COO—, or a phenylene group. L ₂ represents a single bond, an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 18 carbon atoms, —COO—, or —O—, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, or a phenylene group. It is. Rb represents an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 4 to 30 carbon atoms, a bridged alicyclic hydrocarbon group having 5 to 25 carbon atoms, or an aryl group having 6 to 18 carbon atoms; A C1-8 alkyl group (e.g., methyl group, ethyl group, butyl group, t-butyl group); a C5-8 cycloalkyl group (e.g., cyclohexyl group, cyclooctyl group); Represents a bridged alicyclic hydrocarbon group or an aryl group having 6 to 12 carbon atoms (phenyl group, naphthyl group, etc.). These groups may have a substituent. Examples of the substituent include a halogen atom (Cl, Br, etc.), a cyano group, an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a And an acyl group having 1 to 4 carbon atoms and an aryl group having 6 to 12 carbon atoms. Preferred skeletons of the bridged alicyclic hydrocarbon group having 5 to 20 carbon atoms are described below.

  Particularly preferred examples of these groups include (5), (6), (7), (8), (9), (10), (13), (14), (15), and (23). ), (28), (36), (37), (40), (42), and (47).

  When the resin for a resist underlayer film used in the present invention is the above-mentioned copolymer, the content of the repeating unit represented by the general formula (1) is 0 to 80 mol% with respect to all the repeating units of the copolymer. Is more preferable, and more preferably 0 to 60 mol%. In addition to this repeating unit, the copolymer may be a copolymer having another repeating unit for the purpose of improving film-forming properties, adhesion, developability, and the like.

  The resin for a resist underlayer film used in the present invention contains, in addition to the repeating unit represented by the general formula (1), another repeating unit for the purpose of improving film forming properties, adhesion, developability, and the like. May be used. Examples of the monomer corresponding to such another repeating unit include, for example, an addition-polymerizable monomer selected from acrylates, methacrylates, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, and the like. Compounds having one saturated bond are exemplified.

  Specifically, for example, acrylates, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) acrylate (for example, methyl acrylate, ethyl acrylate, propyl acrylate, amyl acrylate, acrylic Cyclohexyl acid, ethylhexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate etc);

Methacrylic esters, for example, alkyl (the alkyl group preferably has 1 to 10 carbon atoms) methacrylate (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate) Chlorobenzyl methacrylate, octyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc.);

Acrylamides, for example, acrylamide, N-alkylacrylamide (alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, propyl group, butyl group, t-butyl group, heptyl group, octyl group, cyclohexyl group , Hydroxyethyl group, etc.), N, N-dialkylacrylamide (alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, butyl group, isobutyl group, ethylhexyl group, cyclohexyl group, etc.) ), N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like;

Methacrylamides, for example, methacrylamide, N-alkyl methacrylamide (an alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a t-butyl group, an ethylhexyl group, a hydroxyethyl group, a cyclohexyl group, etc. ), N, N-dialkylmethacrylamide (an alkyl group includes an ethyl group, a propyl group, a butyl group and the like), N-hydroxyethyl-N-methylmethacrylamide and the like;

Allyl compounds, for example, allyl esters (for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol and the like;

Vinyl ethers such as alkyl vinyl ethers (for example, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether; Hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.);

Vinyl esters such as vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, and vinyl acetoacetate , Vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate and the like;

Dialkyl itaconates (eg, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.); dialkyl esters of fumaric acid (eg, dibutyl fumarate, etc.) or monoalkyl esters; acrylic acid, methacrylic acid, crotonic acid, itaconic acid , Maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, maleilenitrile and the like. In addition, any addition-polymerizable unsaturated compound copolymerizable with the above various repeating units may be used.

  Preferable examples of the phenolic polymer include the following.

  The resin for the resist underlayer film may be used alone or in combination of two or more.

  In a preferred embodiment, the composition for forming a resist underlayer film contains a solvent, an acid generator, a crosslinking agent, a surfactant, and the like, in addition to a resin. In this case, it is preferable to form a crosslinked film by exposing or heating the coating film formed from the composition for forming a resist underlayer film, and to use this as a resist underlayer film.

<Acid generator>
The composition for forming a resist underlayer film may optionally contain an acid generator. The acid generator is a component that generates an acid upon exposure or heating. By containing an acid generator, inhibition of a crosslinking reaction in the resist underlayer film (substances generated from a substrate (particularly, a low dielectric film) (for example, bases such as OH—, CH ₃ —, and NH ₂ —)). Diffusion into the film makes it possible to eliminate the problem of deactivating the acid in the resist underlayer film and inhibiting the crosslinking reaction). In other words, the acid generator in the formed resist underlayer film reacts with the inhibitor, thereby making it possible to prevent the inhibitor from diffusing into the resist underlayer film.
Among the acid generators, examples of the acid generator that generates an acid upon exposure (hereinafter also referred to as “photoacid generator”) are described, for example, in paragraphs [0076] to [0081] of WO 07/105776. And the like.

Among these photoacid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrene sulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalene sulfonate, Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-tert-butylphenyl) iodonium 10-camphorsulfonate, bis (4-tert-butylphenyl) ) Iodonium naphthalene sulfonate are preferred, bis (4-t- butylphenyl) iodonium nonafluoro -n- butane sulfonate is more preferable. These photoacid generators can be used alone or in combination of two or more.
As the photoacid generator, a photoacid generator described later in the resist composition can also be preferably used.

  Examples of the acid generator that generates an acid upon heating (hereinafter, also referred to as “thermal acid generator”) include, for example, 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl Tosylate, alkylsulfonates and the like can be mentioned. These thermal acid generators can be used alone or in combination of two or more. It should be noted that a photoacid generator and a thermal acid generator can be used in combination as the acid generator.

  The content of the acid generator is preferably 100 parts by mass or less, more preferably 0.1 part by mass to 30 parts by mass, and more preferably 0.1 part by mass to 10 parts by mass with respect to 100 parts by mass of the resin for a resist underlayer film. Is particularly preferred.

<Crosslinking agent>
When the composition for forming a resist underlayer film contains a crosslinking agent, the resist underlayer film can be cured at a lower temperature to form a protective film for the substrate to be processed.
As such a crosslinking agent, various curing agents can be used in addition to polynuclear phenols. Examples of the polynuclear phenols include dinuclear phenols such as 4,4'-biphenyldiol, 4,4'-methylenebisphenol, 4,4'-ethylidenebisphenol, and bisphenol A; 4,4 ', 4'' -Trinuclear phenols such as methylidene trisphenol, 4,4 '-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol; polyphenols such as novolak Is mentioned. Among them, 4,4 ′-[1- [4- [1- (4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol and novolak are preferable. In addition, these polynuclear phenols can be used alone or in combination of two or more.
Examples of the curing agent include diisocyanates, epoxy compounds, melamine-based curing agents, benzoguanamine-based curing agents, and glycoluril-based curing agents. Among these, a melamine-based curing agent and a glycoluril-based curing agent are preferred, and 1,3,4,6-tetrakis (methoxymethyl) glycoluril is more preferred. These curing agents can be used alone or in combination of two or more. In addition, a polynuclear phenol and a curing agent can be used in combination as a crosslinking agent.

  The content of the crosslinking agent is preferably 100 parts by mass or less, more preferably 1 part by mass to 20 parts by mass, particularly preferably 1 part by mass to 10 parts by mass with respect to 100 parts by mass of the resin for a resist underlayer film.

<Other optional ingredients>
The resist underlayer film forming composition contains, in addition to the above components, if necessary, other optional components such as a thermosetting polymer, a radiation absorber, a storage stabilizer, an antifoaming agent, and an adhesion aid. May be.

[Step (2): resist film forming step]
In the step (2), a resist film is formed on the resist underlayer film using a resist composition.
First, the members and materials used in the step (2) will be described, and then the procedure of the step (2) will be described.

(Resist composition)
The resist composition of the present invention contains a resin having an atom selected from the group consisting of Si atoms and Ti atoms.
The resist composition of the present invention may be a positive resist composition or a negative resist composition.
The resist composition of the present invention is typically a chemically amplified resist composition.
Hereinafter, each component contained in the resist composition of the present invention will be described.

[1] Resin (A)
The resist composition of the present invention contains a resin having an atom selected from the group consisting of Si atoms and Ti atoms.
The resin (A) is preferably a resin having a repeating unit having an atom selected from the group consisting of a Si atom and a Ti atom.

  The resin (A) is preferably a resin having a Si atom, and more preferably a resin having a repeating unit having a Si atom.

  The content of Si atoms in the resin (A) is preferably from 1 to 30% by mass, more preferably from 3 to 25% by mass, and still more preferably from 5 to 20% by mass. However, the resin (A) has a structure in which a polar group is protected by a leaving group which decomposes and desorbs by the action of an acid (that is, has a acid-decomposable group), and the above-mentioned leaving group is When the resin (A) has Si atoms, the content of the Si atoms in the resin (A) does not include the amount of the Si atoms in the leaving group.

  In the specification of the present application, a repeating unit having both a Si atom and an acid-decomposable group corresponds to a repeating unit having a Si atom and a repeating unit having an acid-decomposable group described later. For example, a resin including only a repeating unit having both a Si atom and an acid-decomposable group corresponds to a resin including a repeating unit having a Si atom and a repeating unit having an acid-decomposable group.

As described above, when the resin (A) is a resin having a Si atom, the resin (A) is preferably a resin having a repeating unit having a Si atom.
The repeating unit having a Si atom is not particularly limited as long as it has a Si atom. For example, a silane-based repeating unit (-SiR ₂ -: _{R 2} is an organic group), a siloxane-based repeating unit _{(-SiR 2} -O-: _R 2 is an organic group), with a Si atoms (meth) acrylate repeating units, And a vinyl-based repeating unit having a Si atom.
The repeating unit having a Si atom preferably has no acid-decomposable group.

The repeating unit having a Si atom preferably has a silsesquioxane structure. The silsesquioxane structure may be present in the main chain or in the side chain, but is preferably present in the side chain.
Examples of the silsesquioxane structure include a cage-type silsesquioxane structure, a ladder-type silsesquioxane structure (ladder-type silsesquioxane structure), and a random silsesquioxane structure. Among them, a cage silsesquioxane structure is preferable.
Here, the cage silsesquioxane structure is a silsesquioxane structure having a cage-like skeleton. The cage silsesquioxane structure may be a complete cage silsesquioxane structure or an incomplete cage silsesquioxane structure, but may be a complete cage silsesquioxane structure. preferable.
The ladder-type silsesquioxane structure is a silsesquioxane structure having a ladder-like skeleton.
The random silsesquioxane structure is a silsesquioxane structure having a random skeleton.

  The cage silsesquioxane structure is preferably a siloxane structure represented by the following formula (S).

In the above formula (S), R represents a monovalent organic group. A plurality of Rs may be the same or different.
The organic group is not particularly limited, and specific examples thereof include a halogen atom, a hydroxy group, a nitro group, a carboxy group, an alkoxy group, an amino group, a mercapto group, and a blocked mercapto group (for example, blocked (protected) by an acyl group). Mercapto group), an acyl group, an imide group, a phosphino group, a phosphinyl group, a silyl group, a vinyl group, a hydrocarbon group optionally having a hetero atom, a (meth) acryl group-containing group and an epoxy group-containing group. No.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.
Examples of the hetero atom of the hydrocarbon group which may have a hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, and a phosphorus atom.
Examples of the hydrocarbon group of the hydrocarbon group optionally having a hetero atom include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group obtained by combining these.
The aliphatic hydrocarbon group may be linear, branched, or cyclic. Specific examples of the aliphatic hydrocarbon group include a linear or branched alkyl group (particularly 1 to 30 carbon atoms), a linear or branched alkenyl group (particularly 2 to 30 carbon atoms), Examples thereof include a linear or branched alkynyl group (particularly, having 2 to 30 carbon atoms).
Examples of the aromatic hydrocarbon group include an aromatic hydrocarbon group having 6 to 18 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

  The repeating unit having a Si atom is preferably represented by the following formula (I).

In the above formula (I), L represents a single bond or a divalent linking group.
Examples of the divalent linking group include an alkylene group, a -COO-Rt- group, a -O-Rt- group, and the like. In the formula, Rt represents an alkylene group or a cycloalkylene group.
L is preferably a single bond or a -COO-Rt- group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group, a — (CH ₂ ) ₂ — group, or a — (CH ₂ ) ₃ — group.
In the above formula (I), X represents a hydrogen atom or an organic group.
Examples of the organic group include an alkyl group which may have a substituent such as a fluorine atom and a hydroxyl group, and a hydrogen atom, a methyl group, a trifluoromethyl group, and a hydroxymethyl group are preferable.
In the above formula (I), A represents a Si-containing group. Among them, a group represented by the following formula (a) or (b) is preferable.

  In the above formula (a), R represents a monovalent organic group. A plurality of Rs may be the same or different. Specific examples and preferred embodiments of R are the same as those in the above formula (S). In addition, when A in the above formula (I) is a group represented by the above formula (a), the above formula (I) is represented by the following formula (Ia).

In the above formula (b), R _b represents a hydrocarbon group which may have a hetero atom. Specific examples and preferred embodiments of the hydrocarbon group optionally having a hetero atom are the same as those of R in the above formula (S).

The repeating unit having a Si atom contained in the resin (A) may be a single type or a combination of two or more types.
The content of the repeating unit having a Si atom with respect to all the repeating units of the resin (A) is not particularly limited, but is preferably 1 to 70 mol%, more preferably 3 to 50 mol%.

  In a resist composition containing a resin having a repeating unit having a Si atom, the resin having a repeating unit having a Si atom generates an outgas at the time of exposure or is eluted into immersion water at the time of immersion exposure, There is a possibility that components containing Si atoms may adhere to the surface of the projection lens to lower the transmittance. As an embodiment for reducing such outgassing and elution, a resin having a repeating unit having a Si atom is stable with respect to an exposure wavelength, or a resin having a repeating unit having a Si atom has a large molecular weight. Are preferably mentioned.

The repeating unit having a Si atom contained in the resin (A) is a repeating unit obtained from a monomer having a turbidity of 1 ppm or less based on JIS K0101: 1998 using formazine as a standard substance and an integrating sphere measuring method as a measuring method. It is preferably a unit. By using a monomer having a turbidity of 1 ppm or less, the scum defect is improved.
The turbidity is preferably 0.8 ppm or less, more preferably 0.1 ppm or less. The turbidity is usually at least 0.01 ppm.
As a method for obtaining a monomer having a silicon atom having the above turbidity, for example, a method of purifying a monomer having a silicon atom after synthesis or commercially available so that the turbidity becomes 1 ppm or less is preferable. As the purification method, a known purification method can be employed. Specifically, for example, filtration, centrifugation, adsorption, liquid separation, distillation, sublimation, crystallization, and a combination of two or more of these methods Can be mentioned.
The repeating unit having a Si atom contained in the resin (A) is preferably a repeating unit obtained from a monomer having a purity (GPC purity) defined by a GPC (Gel Permeation Chromatography) area of 95% or more. By using a monomer having a GPC purity of 95% or more, scum defects after pattern formation are improved.
The GPC purity is more preferably 97% or more, and even more preferably 99% or more. The GPC purity is usually 99.9% or less.
GPC purity can be measured by the test methods described below.
Measurement method of GPC purity: Measurement is performed by GPC (gel permeation chromatography). The column used was a column in which TSKgel SuperHZ 2000 (4.6 mm ID × 15 cm, manufactured by Tosoh Corporation) and TSKgel SuperHZ 1000 (4.6 mm ID × 15 cm, manufactured by Tosoh Corporation) were used. Using tetrahydrofuran, a flow rate of 1.0 mL / min, a column temperature of 40 ° C., a differential refractometer as a detector, a sample is a 0.1% by weight tetrahydrofuran solution, and an injection amount is 100 μL. In the obtained chromatogram, when peaks are separated, vertical division is performed from the minimum value between peaks, and when peaks are overlapped, vertical division is performed from the inflection point between peaks. The area percentage of the main peak is calculated from the area value.
When synthesizing a monomer having a Si atom, any known synthesis method can be employed. For example, the methods described in JP-T-2008-523220 and WO 01/10871 can be used.
The resin solution after polymerization may be purified by a ceramic filter, a nylon filter, or the like.

The resin (A) preferably has a repeating unit having an acid-decomposable group. The repeating unit having an acid-decomposable group preferably has no Si atom.
Here, the acid-decomposable group refers to a group that is decomposed by the action of an acid to generate a polar group.
The acid-decomposable group preferably has a structure in which a polar group is protected by a group capable of decomposing and leaving by the action of an acid (leaving group).
Examples of the polar group include a phenolic hydroxyl group, a carboxyl group, a fluorinated alcohol group (preferably hexafluoroisopropanol group), a sulfonic acid group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl) (alkylcarbonyl) methylene group, and an (alkyl Sulfonyl) (alkylcarbonyl) imide group, bis (alkylcarbonyl) methylene group, bis (alkylcarbonyl) imide group, bis (alkylsulfonyl) methylene group, bis (alkylsulfonyl) imide group, tris (alkylcarbonyl) methylene group, tris An acidic group such as (alkylsulfonyl) methylene group (a group that dissociates in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide) or an alcoholic hydroxyl group.

  The alcoholic hydroxyl group is a hydroxyl group bonded to a hydrocarbon group and refers to a hydroxyl group other than a hydroxyl group (phenolic hydroxyl group) directly bonded to an aromatic ring. Aliphatic alcohols (for example, fluorinated alcohol groups (such as hexafluoroisopropanol groups)) substituted with a functional group are excluded. The alcoholic hydroxyl group is preferably a hydroxyl group having a pKa (acid dissociation constant) of 12 or more and 20 or less.

  Preferred polar groups include a carboxyl group, a fluorinated alcohol group (preferably a hexafluoroisopropanol group), and a sulfonic acid group.

Preferred groups as the acid-decomposable group are groups obtained by substituting a hydrogen atom of these groups with a group capable of leaving with an acid.
In the desorption radicals (leaving) the acid, for _{example, -C (R 36) (R} 37) (R 38), - C (R 36) (R 37) (OR 39), - C (R ₀₁ ) (R ₀₂ ) (OR ₃₉ ) and the like.
In the formula, R _{36 to} R ₃₉ each independently represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may combine with each other to form a ring.
R ₀₁ and R ₀₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

The alkyl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an alkyl group having 1 to 8 carbon atoms, for example, methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group, hexyl And octyl groups.
The cycloalkyl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ may be monocyclic or polycyclic. As the monocyclic type, a cycloalkyl group having 3 to 8 carbon atoms is preferable, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable, for example, an adamantyl group, a norbornyl group, an isobornyl group, a camphanyl group, a dicyclopentyl group, an α-pinel group, a tricyclodecanyl group, and a tetracyclododecyl group And an androstanyl group. In addition, at least one carbon atom in the cycloalkyl group may be substituted by a hetero atom such as an oxygen atom.
The aryl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.
The aralkyl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group and a naphthylmethyl group.
The alkenyl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an alkenyl group having 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.
The ring formed by combining R ₃₆ and R ₃₇ is preferably a cycloalkyl group (monocyclic or polycyclic). As the cycloalkyl group, a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic cycloalkyl group such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group are preferable. A monocyclic cycloalkyl group having 5 to 6 carbon atoms is more preferable, and a monocyclic cycloalkyl group having 5 carbon atoms is particularly preferable.

  The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group, or the like. More preferably, it is a tertiary alkyl ester group.

  The resin (A) preferably has a repeating unit represented by the following general formula (AI) as a repeating unit having an acid-decomposable group. The repeating unit represented by the general formula (AI) generates a carboxyl group as a polar group by the action of an acid.

In the general formula (AI),
Xa ₁ represents a hydrogen atom, an alkyl group, a cyano group, or a halogen atom.
T represents a single bond or a divalent linking group.
Rx _{1 to} Rx ₃ each independently represent an alkyl group or a cycloalkyl group.
Two of Rx _{1 to} Rx ₃ may combine to form a ring structure.

Examples of the divalent linking group for T include an alkylene group, a -COO-Rt- group, a -O-Rt- group, and a phenylene group. In the formula, Rt represents an alkylene group or a cycloalkylene group.
T is preferably a single bond or a -COO-Rt- group. Rt is preferably an alkylene group having 1 to 5 carbon atoms, more preferably a —CH ₂ — group, a — (CH ₂ ) ₂ — group, or a — (CH ₂ ) ₃ — group. T is more preferably a single bond.

The alkyl group of _Xa1 may have a substituent, and examples of the substituent include a hydroxyl group and a halogen atom (preferably, a fluorine atom).
Alkyl group X _a1 is preferably those having 1 to 4 carbon atoms, a methyl group, an ethyl group, a propyl group, a hydroxymethyl group or a trifluoromethyl group and the like, preferably a methyl group.
X _a1 is preferably a hydrogen atom or a methyl group.

The alkyl group for Rx ₁ , Rx ₂ and Rx ₃ may be linear or branched, and may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group. And a t-butyl group. The carbon number of the alkyl group is preferably from 1 to 10, and more preferably from 1 to 5.
Examples of the cycloalkyl group of Rx ₁ , Rx ₂ and Rx ₃ include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group, and a polycyclic ring such as a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Are preferred.

Examples of the ring structure formed by combining two of Rx ₁ , Rx ₂ and Rx ₃ include a monocyclic cycloalkane ring such as a cyclopentyl ring and a cyclohexyl ring, a norbornane ring, a tetracyclodecane ring, a tetracyclododecane ring, and an adamantane ring And a polycyclic cycloalkyl group such as A monocyclic cycloalkane ring having 5 or 6 carbon atoms is particularly preferred.

Rx ₁ , Rx ₂ and Rx ₃ are each independently preferably an alkyl group, more preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

  Each of the above groups may have a substituent. Examples of the substituent include an alkyl group (1 to 4 carbon atoms), a cycloalkyl group (3 to 8 carbon atoms), a halogen atom, an alkoxy group (carbon Formulas 1 to 4), a carboxyl group, an alkoxycarbonyl group (2 to 6 carbon atoms), and the like, and preferably 8 or less carbon atoms. Among them, a substituent having no hetero atom such as an oxygen atom, a nitrogen atom, and a sulfur atom is more preferable from the viewpoint of further improving the dissolution contrast in a developer containing an organic solvent before and after acid decomposition (for example, , More preferably not an alkyl group substituted with a hydroxyl group), further preferably a group consisting only of a hydrogen atom and a carbon atom, and particularly preferably a linear or branched alkyl group or a cycloalkyl group. .

In Formula (AI), Rx _{1 to} Rx ₃ are each independently an alkyl group, and it is preferable that two of Rx _{1 to} Rx ₃ do not combine to form a ring structure. This can suppress an increase in the volume of the group represented by —C (Rx ₁ ) (Rx ₂ ) (Rx ₃ ) as a group which is decomposed and eliminated by the action of an acid. In the post-exposure heating step that may be performed, the volume shrinkage of the exposed portion tends to be suppressed.

Specific examples of the repeating unit represented by the general formula (AI) are shown below, but the present invention is not limited to these specific examples.
In the specific examples, Rx represents a hydrogen atom, CH ₃ , CF ₃ , or CH ₂ OH. Rxa and Rxb each independently represent an alkyl group (preferably an alkyl group having 1 to 10, more preferably 1 to 5 carbon atoms). Xa ₁ represents a hydrogen atom, CH ₃ , CF ₃ , or CH ₂ OH. Z represents a substituent. When a plurality of Zs are present, the plurality of Zs may be the same or different. p represents 0 or a positive integer. Specific examples and preferred examples of Z are the same as the specific examples and preferred examples of the substituent that each group such as Rx _{1 to} Rx ₃ may have.

  Further, the resin (A) also preferably has a repeating unit described in paragraphs [0057] to [0071] of JP-A-2014-202969 as a repeating unit having an acid-decomposable group.

  Further, the resin (A) may have, as a repeating unit having an acid-decomposable group, a repeating unit that produces an alcoholic hydroxyl group described in paragraphs [0072] to [0073] of JP-A-2014-202969. Good.

  The resin (A) also preferably has, as a repeating unit having an acid-decomposable group, a repeating unit having a structure in which a phenolic hydroxyl group is protected by a leaving group which is decomposed and eliminated by the action of an acid. In the present specification, the phenolic hydroxyl group is a group obtained by replacing a hydrogen atom of an aromatic hydrocarbon group with a hydroxyl group. The aromatic ring of the aromatic hydrocarbon group is a monocyclic or polycyclic aromatic ring, such as a benzene ring and a naphthalene ring.

  As the repeating unit having a structure in which a phenolic hydroxyl group is decomposed and desorbed by the action of an acid and protected by a leaving group, a repeating unit represented by the following general formula (AII) is preferable.

In the general formula (AII),
R ₆₁ , R ₆₂ and R ₆₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an alkoxycarbonyl group. However, R ₆₂ may be bonded to Ar ₆ to form a ring, in which case R ₆₂ represents a single bond or an alkylene group.
X ₆ represents a single bond, —COO—, or —CONR ₆₄ —. R ₆₄ represents a hydrogen atom or an alkyl group.
L ₆ represents a single bond or an alkylene group.
Ar ₆ represents an (n + 1) -valent aromatic hydrocarbon group, and represents an (n + 2) -valent aromatic hydrocarbon group when bonded to R ₆₂ to form a ring.
Y ₂ independently represents a hydrogen atom or a group capable of leaving by the action of an acid when n ≧ 2. However, at least one of Y ₂ represents a group which is eliminated by the action of an acid. The group leaving by the action of an acid as Y ₂ is preferably those listed above as the leaving group.
n represents an integer of 1 to 4.

  Each of the above groups may have a substituent. Examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and Examples thereof include an alkoxycarbonyl group (2 to 6 carbon atoms), and those having 8 or less carbon atoms are preferable.

  One type of repeating unit having an acid-decomposable group may be used, or two or more types may be used in combination.

  The content of the repeating unit having an acid-decomposable group contained in the resin (A) (when there are a plurality of repeating units having an acid-decomposable group, the sum thereof) is based on the total repeating units of the resin (A). It is preferably from 20 to 90 mol%, more preferably from 40 to 80 mol%. Above all, the resin (A) has a repeating unit represented by the general formula (AI), and the content of the repeating unit represented by the general formula (AI) is 40 mol based on all repeating units of the resin (A). % Is preferable.

  The resin (A) preferably has at least one selected from the group consisting of a lactone structure, a sultone structure, and a carbonate structure, and is selected from the group consisting of a lactone structure, a sultone structure, and a carbonate structure. It is more preferred to have at least one type of repeating unit.

  Any lactone structure or sultone structure can be used as long as it has a lactone structure or a sultone structure, but is preferably a 5- to 7-membered lactone structure or a 5- to 7-membered sultone structure. A bicyclic structure or a spiro structure is formed in a membered lactone structure and another ring structure is condensed, or a 5- to 7-membered sultone structure is formed in a bicyclo structure or a spiro structure to form another ring. Those having a fused ring structure are more preferred. A lactone structure represented by any of the following general formulas (LC1-1) to (LC1-21), or a sultone structure represented by any of the following general formulas (SL1-1) to (SL1-3); It is more preferred to have a repeating unit having the formula: Further, a lactone structure or a sultone structure may be directly bonded to the main chain. Preferred lactone structures are (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (LC1-14), and (LC1-17). A preferred lactone structure is (LC1-4). By using such a specific lactone structure, LER and development defects are improved.

The lactone structure portion or the sultone structure portion may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms, and a carboxyl group. , A halogen atom, a hydroxyl group, a cyano group, an acid-decomposable group, and the like. More preferred are an alkyl group having 1 to 4 carbon atoms, a cyano group, and an acid-decomposable group. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of substituents (Rb ₂ ) may be the same or different. Further, a plurality of substituents (Rb ₂ ) may be bonded to each other to form a ring.

  The repeating unit having a lactone structure or a sultone structure usually has an optical isomer, but any optical isomer may be used. Further, one kind of optical isomer may be used alone, or a plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) is preferably 90% or more, more preferably 95% or more.

  The repeating unit having a lactone structure or a sultone structure is preferably a repeating unit represented by the following general formula (III).

In the above general formula (III),
A represents an ester bond (a group represented by -COO-) or an amide bond (a group represented by -CONH-).
When there are a plurality of R _{0 s} , each independently represents an alkylene group, a cycloalkylene group, or a combination thereof.
Z is a single bond, an ether bond, an ester bond, an amide bond, a urethane bond when there are a plurality of

Or urea bond

Represents Here, each R independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group.
R ₈ represents a monovalent organic group having a lactone structure or a sultone structure.
n _is the repetition number of the structure represented by -R 0 -Z-, represents an integer of 0 to 5, preferably 0 or 1, and more preferably 0. When n is _0, -R 0 -Z- is not present, the single bond.
R ₇ represents a hydrogen atom, a halogen atom or an alkyl group.

The alkylene group and cycloalkylene group of R ₀ may have a substituent.
Z is preferably an ether bond or an ester bond, and particularly preferably an ester bond.

The alkyl group for R ₇ is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.
The alkylene group of R ₀ , the cycloalkylene group, and the alkyl group of R ₇ may be each substituted. Examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, a mercapto group, a hydroxyl group, Examples include an alkoxy group such as a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group and a benzyloxy group, and an acyloxy group such as an acetyloxy group and a propionyloxy group.
R ₇ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.

The preferred chain alkylene group for R ₀ is preferably a chain alkylene group having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and examples thereof include a methylene group, an ethylene group, and a propylene group. Preferred cycloalkylene groups are cycloalkylene groups having 3 to 20 carbon atoms, such as cyclohexylene, cyclopentylene, norbornylene, and adamantylene. In order to exhibit the effects of the present invention, a chain alkylene group is more preferable, and a methylene group is particularly preferable.

The monovalent organic group having a lactone structure or a sultone structure represented by R ₈ is not limited as long as it has a lactone structure or a sultone structure, and specific examples thereof include general formulas (LC1-1) to (LC1-1). LC1-21) and a lactone structure or a sultone structure represented by any of (SL1-1) to (SL1-3), and among these, the structure represented by (LC1-4) is particularly preferable. preferable. Further, _{n 2} is more preferably of 2 or less in (LC1-1) ~ (LC1-21).
R ₈ is preferably an unsubstituted monovalent organic group having a lactone structure or a sultone structure, or a monovalent organic group having a lactone structure or a sultone structure having a methyl group, a cyano group or an alkoxycarbonyl group as a substituent. And a monovalent organic group having a lactone structure (cyanolactone) having a cyano group as a substituent.

  Specific examples of the repeating unit having a group having a lactone structure or a sultone structure are shown below, but the present invention is not limited thereto.

  In order to enhance the effects of the present invention, two or more types of repeating units having a lactone structure or a sultone structure can be used in combination.

  When the resin (A) contains a repeating unit having a lactone structure or a sultone structure, the content of the repeating unit having a lactone structure or a sultone structure is 5 to 60 mol% based on all repeating units in the resin (A). Is more preferable, more preferably 5 to 55 mol%, and still more preferably 10 to 50 mol%.

  The repeating unit having a carbonate structure (cyclic carbonate structure) is preferably a repeating unit represented by the following general formula (A-1).

In Formula (A-1), R _A ¹ represents a hydrogen atom or an alkyl group.
R _A ² are each independently of when n is 2 or more, it represents a substituent.
A represents a single bond or a divalent linking group.
Z represents an atomic group forming a monocyclic or polycyclic structure together with the group represented by -OC (= O) -O- in the formula.
n represents an integer of 0 or more.

The general formula (A-1) will be described in detail.
The alkyl group represented by R _A ¹ may have a substituent such as a fluorine atom. R _A ¹ represents a hydrogen atom, preferably represents a methyl group or a trifluoromethyl group, and more preferably a methyl group.
Substituents represented by R _A ² is, for example, an alkyl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonylamino group. Preferably it is a C1-C5 alkyl group, for example, a C1-C5 linear alkyl group, such as a methyl group, an ethyl group, a propyl group, and a butyl group; an isopropyl group, an isobutyl group, and a t-butyl group And other branched alkyl groups having 3 to 5 carbon atoms. The alkyl group may have a substituent such as a hydroxyl group.
n is an integer of 0 or more representing the number of substituents. n is, for example, preferably 0 to 4, and more preferably 0.

Examples of the divalent linking group represented by A include an alkylene group, a cycloalkylene group, an ester bond, an amide bond, an ether bond, a urethane bond, a urea bond, and a combination thereof. As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, and an alkylene group having 1 to 5 carbon atoms is more preferable, and examples thereof include a methylene group, an ethylene group, and a propylene group.
In one embodiment of the present invention, A is preferably a single bond or an alkylene group.

Represented by Z, The monocyclic ring containing -O-C (= O) -O- , e.g., in the cyclic carbonate represented by the following general formula _(a), an n A = 2 to 4 5 to 7-membered ring, and is preferably a 5- or 6-membered ring _(n a = 2 or 3), more preferably a 5-membered ring _(n a = 2).
As the polycyclic ring containing -OC (= O) -O- represented by Z, for example, a cyclic carbonic acid ester represented by the following general formula (a) may be used together with one or more other ring structures. Examples include a structure forming a condensed ring and a structure forming a spiro ring. The `` other ring structure '' capable of forming a condensed ring or a spiro ring may be an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic ring. .

  The monomer corresponding to the repeating unit represented by the general formula (A-1) is described in, for example, Tetrahedron Letters, Vol. 27, no. 32 p. 3741 (1986), Organic Letters, Vol. 4, No. 15 p. 2561 (2002) and the like, and can be synthesized by a conventionally known method.

The resin (A) may contain one kind alone or two or more kinds of the repeating units represented by the general formula (A-1).
In the resin (A), the content of the repeating unit having a cyclic carbonate structure (preferably, the repeating unit represented by the general formula (A-1)) is based on the total repeating units constituting the resin (A). , Preferably 3 to 80 mol%, more preferably 3 to 60 mol%, further preferably 3 to 45 mol%, particularly preferably 3 to 30 mol%, and 10 to 10 mol%. Most preferably, it is 15 mol%. With such a content, the developability, low defectivity, low LWR (Line Width Roughness), low PEB (Post Exposure Bake) temperature dependency, profile, and the like of the resist can be improved.

Hereinafter, specific examples of the repeating unit represented by Formula (A-1) will be given, but the present invention is not limited thereto.
Incidentally, _R ^{A 1} in the following specific examples are the same meaning as _R ^{A 1} in the general formula (A-1).

The resin (A) may have a repeating unit having a phenolic hydroxyl group.
Examples of the repeating unit having a phenolic hydroxyl group include a hydroxystyrene repeating unit or a hydroxystyrene (meth) acrylate repeating unit. As the repeating unit having a phenolic hydroxyl group, a repeating unit represented by the following general formula (I) is particularly preferred.

Where:
R ₄₁ , R ₄₂ and R ₄₃ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an alkoxycarbonyl group. However, R ₄₂ may combine with Ar ₄ to form a ring, in which case R ₄₂ represents a single bond or an alkylene group.
X ₄ represents a single bond, —COO—, or —CONR ₆₄ —, and R ₆₄ represents a hydrogen atom or an alkyl group.
L ₄ represents a single bond or a divalent linking group.
Ar ₄ represents an (n + 1) -valent aromatic hydrocarbon group, and represents an (n + 2) -valent aromatic hydrocarbon group when bonded to R ₄₂ to form a ring.
n represents an integer of 1 to 5.
For the purpose of increasing the polarity of the repeating unit represented by the general formula (I), it is also preferable that n is an integer of 2 or more, or X ₄ is —COO— or —CONR ₆₄ —.

The alkyl group represented by R ₄₁ , R ₄₂ and R ₄₃ in the general formula (I) includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, which may have a substituent. An alkyl group having 20 or less carbon atoms such as a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, and a dodecyl group is preferable, an alkyl group having 8 or less carbon atoms is more preferable, and an alkyl group having 3 or less carbon atoms is preferable. More preferred.

The cycloalkyl group represented by R ₄₁ , R ₄₂ and R ₄₃ in the general formula (I) may be monocyclic or polycyclic. A monocyclic cycloalkyl group having 3 to 8 carbon atoms such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group which may have a substituent is preferable.
Examples of the halogen atom represented by R ₄₁ , R ₄₂ and R ₄₃ in the general formula (I) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
As the alkyl group contained in the alkoxycarbonyl group represented by R ₄₁ , R ₄₂ and R ₄₃ in the general formula (I), the same alkyl groups as those described above for R ₄₁ , R ₄₂ and R ₄₃ are preferable.

  Preferred substituents in each of the above groups include, for example, an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, and an acyl group. Groups, an acyloxy group, an alkoxycarbonyl group, a cyano group, a nitro group and the like, and the substituent preferably has 8 or less carbon atoms.

Ar ₄ represents an (n + 1) -valent aromatic hydrocarbon group. The divalent aromatic hydrocarbon group when n is 1 may have a substituent, for example, arylene having 6 to 18 carbon atoms such as a phenylene group, a tolylene group, a naphthylene group, and an anthracenylene group. Preferred are groups or aromatic hydrocarbon groups containing heterocycles such as, for example, thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzimidazole, triazole, thiadiazole and thiazole.

Specific examples of the (n + 1) -valent aromatic hydrocarbon group when n is an integer of 2 or more include, from the above-described specific examples of the divalent aromatic hydrocarbon group, (n-1) arbitrary arbitrary groups. A group obtained by removing a hydrogen atom can be preferably exemplified.
The (n + 1) -valent aromatic hydrocarbon group may further have a substituent.

Examples of the substituent which the above-mentioned alkyl group, cycloalkyl group, alkoxycarbonyl group and (n + 1) -valent aromatic hydrocarbon group may have include, for example, R ₄₁ , R ₄₂ and R ₄₃ in the general formula (I). The above-mentioned alkyl groups; alkoxy groups such as methoxy group, ethoxy group, hydroxyethoxy group, propoxy group, hydroxypropoxy group and butoxy group; aryl groups such as phenyl group;
_-CONR 64 represented by X ₄ - _{(R 64} represents a hydrogen atom or an alkyl group) The alkyl group for _{R 64} in, which may have a substituent, a methyl group, an ethyl group, a propyl group , An isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, and an alkyl group having 20 or less carbon atoms such as a dodecyl group, and an alkyl group having 8 or less carbon atoms is more preferable. .
X ₄ is preferably a single bond, —COO—, or —CONH—, and more preferably a single bond or —COO—.

The divalent linking group as L ₄ is preferably an alkylene group. As the alkylene group, a methylene group, ethylene group, propylene group, butylene group, hexylene group, which may have a substituent, And an alkylene group having 1 to 8 carbon atoms such as octylene group.
Ar ₄ is preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and more preferably a benzene ring group, a naphthalene ring group, or a biphenylene ring group. Among them, the repeating unit represented by the general formula (I) is preferably a repeating unit derived from hydroxystyrene. That is, Ar ₄ is preferably a benzene ring group.

  Hereinafter, specific examples of the repeating unit having a phenolic hydroxyl group are shown, but the present invention is not limited thereto. In the formula, a represents 1 or 2.

  The resin (A) may have a single type of repeating unit having a phenolic hydroxyl group, or may have a combination of two or more types.

  In the resin (A), the content of the repeating unit having a phenolic hydroxyl group is preferably at least 40 mol%, more preferably at least 50 mol%, and preferably at least 60 mol%, based on all repeating units in the resin (A). Is more preferably 85 mol% or less, and more preferably 80 mol% or less.

  The resin (A) preferably has a repeating unit having a hydroxyl group or a cyano group other than the above-mentioned repeating unit. Thereby, the substrate adhesion and the developer affinity are improved. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and preferably has no acid-decomposable group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As a preferred alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, a structure represented by the following general formula is preferable.

The content of the repeating unit having a hydroxyl group or a cyano group is preferably 5 to 40 mol%, more preferably 5 to 30 mol%, and still more preferably 10 to 25 mol%, based on all the repeating units in the resin (A).
Specific examples of the repeating unit having a hydroxyl group or a cyano group include a repeating unit disclosed in paragraph 0340 of US Patent Publication No. 2012/0135348, but the present invention is not limited thereto.

The resin (A) may have a repeating unit having an alkali-soluble group. Examples of the alkali-soluble group include a carboxyl group, a sulfonamide group, a sulfonylimide group, a bissulfonylimide group, and an aliphatic alcohol in which the α-position is substituted with an electron-withdrawing group (for example, hexafluoroisopropanol group). It is more preferred to have a repeating unit having By containing a repeating unit having an alkali-soluble group, the resolution for contact hole use is increased. Examples of the repeating unit having an alkali-soluble group include a repeating unit in which an alkali-soluble group is directly bonded to the main chain of the resin, such as a repeating unit of acrylic acid and methacrylic acid, or an alkali-soluble group connected to the main chain of the resin via a linking group. A repeating unit to which a soluble group is bonded, and further introduced at the end of a polymer chain using a polymerization initiator or a chain transfer agent having an alkali-soluble group at the time of polymerization, both are preferable, and the linking group is a monocyclic or polycyclic one. It may have a cyclic hydrocarbon structure. Particularly preferred are repeating units of acrylic acid and methacrylic acid.
The content of the repeating unit having an alkali-soluble group is preferably from 0 to 20 mol%, more preferably from 3 to 15 mol%, and still more preferably from 5 to 10 mol%, based on all repeating units in the resin (A).
Specific examples of the repeating unit having an alkali-soluble group include the repeating unit disclosed in paragraph 0344 of US Patent Publication No. 2012/0135348, but the present invention is not limited to this.

  The resin (A) of the present invention may further have an alicyclic hydrocarbon structure having no polar group (for example, the above-mentioned alkali-soluble group, hydroxyl group, cyano group, etc.) and may have a repeating unit that does not exhibit acid-decomposability. it can. Examples of such a repeating unit include a repeating unit represented by the general formula (IV).

In the general formula (IV), R ₅ represents a hydrocarbon group having at least one cyclic structure and having no polar group.
Ra represents a hydrogen atom, an alkyl group or a —CH ₂ —O—Ra ₂ group. In the formula, Ra ₂ represents a hydrogen atom, an alkyl group or an acyl group. Ra is preferably a hydrogen atom, a methyl group, a hydroxymethyl group, or a trifluoromethyl group, and particularly preferably a hydrogen atom or a methyl group.
The cyclic structure of R ₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include cycloalkyl groups having 3 to 12 carbon atoms such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group, and cycloalkenyl groups having 3 to 12 carbon atoms such as cyclohexenyl group. Groups. Preferred monocyclic hydrocarbon groups are monocyclic hydrocarbon groups having 3 to 7 carbon atoms, and more preferred are a cyclopentyl group and a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring-assembled hydrocarbon group and a bridged cyclic hydrocarbon group, and examples of the ring-assembled hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. As the bridged cyclic hydrocarbon ring, for example, bicyclic such as pinane, bornane, norpinane, norbornane, bicyclooctane ring (bicyclo [2.2.2] octane ring, bicyclo [3.2.1] octane ring, etc.) A hydrocarbon ring, a tricyclic hydrocarbon ring such as homobledan, adamantane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [4.3.1.1 ^2,5 ] undecane ring, tetracyclo [ 4.4.0.1 ^2,5 . [ ^7,10 ] dodecane, tetracyclic hydrocarbon rings such as perhydro-1,4-methano-5,8-methanonaphthalene ring and the like. Also, the bridged cyclic hydrocarbon ring includes a condensed cyclic hydrocarbon ring, for example, perhydronaphthalene (decalin), perhydroanthracene, perhydrophenanthrene, perhydroacenaphthene, perhydrofluorene, perhydroindene, perhydroindene A condensed ring formed by condensing a plurality of 5- to 8-membered cycloalkane rings such as a phenalene ring is also included.
Preferred bridged cyclic hydrocarbon rings include a norbornyl group, an adamantyl group, a bicyclooctanyl group, a tricyclo [5,2,1,0 ^2,6 ] decanyl group, and the like. More preferred crosslinked cyclic hydrocarbon rings include a norbornyl group and an adamantyl group.

These alicyclic hydrocarbon groups may have a substituent, and preferred substituents include a halogen atom, an alkyl group, a hydroxyl group substituted with a hydrogen atom, and an amino group substituted with a hydrogen atom. Can be Preferred halogen atoms include bromine, chlorine and fluorine atoms, and preferred alkyl groups include methyl, ethyl, butyl and t-butyl groups. The above-mentioned alkyl group may further have a substituent, and as a substituent which may further have, a halogen atom, an alkyl group, a hydroxyl group substituted with a hydrogen atom, an amino group substituted with a hydrogen atom Groups.
Examples of the group in which the hydrogen atom is substituted include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group. Preferred alkyl groups are alkyl groups having 1 to 4 carbon atoms, preferred substituted methyl groups are methoxymethyl, methoxythiomethyl, benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl group, and preferred substituted ethyl groups are , 1-ethoxyethyl, 1-methyl-1-methoxyethyl, and preferred acyl groups include aliphatic acyl groups having 1 to 6 carbon atoms such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl and pivaloyl groups, and alkoxycarbonyl Examples of the group include an alkoxycarbonyl group having 1 to 4 carbon atoms.

The resin (A) has an alicyclic hydrocarbon structure having no polar group, and may or may not contain a repeating unit having no acid-decomposability. Is preferably 1 to 40 mol%, more preferably 2 to 20 mol%, based on all repeating units in the resin (A).
Specific examples of the repeating unit having an alicyclic hydrocarbon structure having no polar group and exhibiting no acid-decomposability include the repeating unit disclosed in paragraph 0354 of U.S. Patent Publication No. 2012/0135348. However, the present invention is not limited to these.

The resin (A) used in the method of the present invention may contain, in addition to the above-mentioned repeating structural units, dry etching resistance, suitability for a standard developer, substrate adhesion, a resist profile, and resolution which is a general necessary property of a resist. It can have various repeating structural units for the purpose of adjusting heat resistance, sensitivity and the like. Examples of such a repeating structural unit include, but are not limited to, repeating structural units corresponding to the following monomers.
Thereby, the performance required for the resin (A) used in the method of the present invention, in particular, (1) solubility in a coating solvent, (2) film-forming property (glass transition point), (3) alkali developability, Fine adjustments such as (4) film loss (selection of hydrophilic / hydrophobic and alkali-soluble groups), (5) adhesion of the unexposed portion to the substrate, and (6) dry etching resistance can be performed.

As such a monomer, for example, a compound having one addition-polymerizable unsaturated bond selected from acrylates, methacrylates, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, and the like And the like.
In addition, as long as it is an addition-polymerizable unsaturated compound copolymerizable with a monomer corresponding to the above-mentioned various repeating structural units, it may be copolymerized.
In the resin (A), the molar ratio of each repeating structural unit is determined by the dry etching resistance of the resist, the suitability for a standard developer, the substrate adhesion, the resist profile, and the resolution, heat resistance, and sensitivity, which are general required properties of the resist. It is set as appropriate to adjust etc.

  When the resist composition of the present invention is used for ArF exposure, the resin (A) preferably has substantially no aromatic group from the viewpoint of transparency to ArF light. More specifically, in all the repeating units of the resin (A), the content of the repeating unit having an aromatic group is preferably 5 mol% or less, more preferably 3 mol% or less, and ideally. Is more preferably 0 mol%, that is, does not have a repeating unit having an aromatic group. Further, the resin (A) preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.

  In addition, it is also preferable that the resin (A) does not contain a fluorine atom and a silicon atom.

  The resin (A) is preferably one in which all of the repeating units are composed of (meth) acrylate-based repeating units. In this case, any of those in which all of the repeating units are methacrylate-based repeating units, those in which all of the repeating units are acrylate-based repeating units, and those in which all of the repeating units are composed of methacrylate-based repeating units and acrylate-based repeating units. Although it can be used, it is preferable that the acrylate-based repeating unit accounts for 50 mol% or less of all the repeating units.

The resin (A) can be synthesized according to a conventional method (for example, radical polymerization). For example, as a general synthesis method, a batch polymerization method in which a monomer species and an initiator are dissolved in a solvent and polymerization is performed by heating, a solution of the monomer species and the initiator is dropped in a heating solvent over 1 to 10 hours. Drop polymerization method, and the like, and the drop polymerization method is preferable. As the reaction solvent, for example, ethers such as tetrahydrofuran, 1,4-dioxane, diisopropyl ether and the like, methyl ethyl ketone, ketones such as methyl isobutyl ketone, ester solvents such as ethyl acetate, dimethylformamide, amide solvents such as dimethylacetamide, Further, a solvent that dissolves the resist composition of the present invention, such as propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and cyclohexanone described below, may be used. More preferably, polymerization is carried out using the same solvent as that used in the resist composition of the present invention. Thereby, generation of particles during storage can be suppressed.
The polymerization reaction is preferably performed in an atmosphere of an inert gas such as nitrogen or argon. The polymerization is started using a commercially available radical initiator (such as an azo-based initiator or a peroxide) as the polymerization initiator. As the radical initiator, an azo initiator is preferable, and an azo initiator having an ester group, a cyano group, and a carboxyl group is preferable. Preferred initiators include azobisisobutyronitrile, azobisdimethylvaleronitrile, dimethyl 2,2′-azobis (2-methylpropionate) and the like. If desired, an initiator is added or added in portions, and after completion of the reaction, the mixture is poured into a solvent and a desired polymer is recovered by a method such as powder or solid recovery. The solid content concentration in the reaction solution is 5 to 50% by mass, preferably 10 to 30% by mass. The reaction temperature is usually from 10C to 150C, preferably from 30C to 120C, more preferably from 60C to 100C.
In addition, the resin (A) may be any of a random polymer, a block polymer, and a graft polymer.

The weight average molecular weight of the resin (A) is preferably from 1,000 to 200,000, more preferably from 2,000 to 40,000, still more preferably from 3,000 to 30,000, particularly preferably from 4,000. 2,000 to 25,000. When the weight average molecular weight is 1,000 to 200,000, deterioration of heat resistance and dry etching resistance can be prevented, and developability is deteriorated, and viscosity is increased to deteriorate film formability. Can be prevented.
The dispersity (molecular weight distribution) of the resin (A) is usually 1.0 to 3.0, preferably 1.0 to 2.6, more preferably 1.0 to 2.0, and particularly preferably 1. Those having a range of 1 to 2.0 are used. The smaller the molecular weight distribution, the better the resolution and the resist shape, the smoother the side wall of the resist pattern, and the better the roughness.
In the specification of the present application, the weight average molecular weight (Mw) and the degree of dispersion are standard polystyrene conversion values determined by gel permeation chromatography (GPC) under the following conditions.
-Type of column: TSK gel Multipore HXL-M (manufactured by Tosoh Corporation, 7.8 mm ID x 30.0 cm)
・ Developing solvent: THF (tetrahydrofuran)
・ Column temperature: 40 ° C. ・ Flow rate: 1 ml / min
・ Sample injection volume: 10 μl
-Equipment name: HLC-8120 (manufactured by Tosoh Corporation)

The content of the resin (A) is preferably 20% by mass or more, more preferably 40% by mass or more, and further preferably 60% by mass or more, based on the total solid content of the resist composition. It is particularly preferably at least 80% by mass. The content of the resin (A) is preferably 99% by mass or less based on the total solid content of the resist composition.
In the present invention, the resin (A) may be used alone or in combination of two or more.

[2] Compound that Generates Acid by Irradiation with Actinic Ray or Radiation The resist composition of the present invention contains a compound that generates an acid by irradiation with actinic ray or radiation (hereinafter, also referred to as “photoacid generator”). Is preferred. The photoacid generator is not particularly limited, but is preferably a compound that generates an organic acid upon irradiation with actinic rays or radiation.
As a photoacid generator, a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, a photodecolorant for dyes, a photochromic agent, or a microresist, etc. Known compounds that generate an acid upon irradiation and mixtures thereof can be appropriately selected and used, for example, compounds described in paragraphs [0039] to [0103] of JP-A-2010-61043, Examples include compounds described in paragraphs [0284] to [0389] of JP-A-2013-4820, but the present invention is not limited thereto.
For example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imidosulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzylsulfonates can be mentioned.

  As the photoacid generator contained in the resist composition of the present invention, for example, a compound (specific photoacid generator) represented by the following general formula (3) that generates an acid upon irradiation with actinic rays or radiation is preferable. Can be mentioned.

(Anion)
In the general formula (3),
Xf each independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom.
R ₄ and R ₅ each independently represent a hydrogen atom, a fluorine atom, an alkyl group, or an alkyl group substituted with at least one fluorine atom, and when there are a plurality of R ₄ and R ₅ , But they may be different.
L represents a divalent linking group, and when a plurality of L are present, L may be the same or different.
W represents an organic group containing a cyclic structure.
o represents an integer of 1 to 3. p represents an integer of 0 to 10. q represents an integer of 0 to 10.

Xf represents a fluorine atom or an alkyl group substituted with at least one fluorine atom. The alkyl group preferably has 1 to 10 carbon atoms, and more preferably 1 to 4 carbon atoms. Further, the alkyl group substituted with at least one fluorine atom is preferably a perfluoroalkyl group.
Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4 carbon atoms. Xf is more preferably a fluorine atom or CF ₃ . In particular, it is preferable that both Xf are fluorine atoms.

R ₄ and R ₅ each independently represent a hydrogen atom, a fluorine atom, an alkyl group, or an alkyl group substituted with at least one fluorine atom, and when there are a plurality of R ₄ and R ₅ , But they may be different.
The alkyl group as R ₄ and R ₅ may have a substituent, and preferably has 1 to 4 carbon atoms. R ₄ and R ₅ are preferably a hydrogen atom.
Specific examples and preferred embodiments of the alkyl group substituted with at least one fluorine atom are the same as the specific examples and preferred embodiments of Xf in formula (3).

L represents a divalent linking group, and when a plurality of L are present, L may be the same or different.
Examples of the divalent linking group include -COO-(-C (= O) -O-), -OCO-, -CONH-, -NHCO-, -CO-, -O-, -S-,- SO -, - SO ₂ -, an alkylene group (preferably having 1 to 6 carbon atoms), a cycloalkylene group (preferably having from 3 to 10 carbon atoms), an alkenylene group (preferably having from 2 to 6 carbon atoms), or a combination of these multiple And a divalent linking group. Among them, -COO -, - OCO -, - CONH -, - NHCO -, - CO -, - O -, - SO 2 -, - COO- alkylene group -, - OCO- alkylene group -, - CONH- alkylene group - or -NHCO- alkylene group - are preferred, -COO -, - OCO -, - CONH -, - SO 2 -, - COO- alkylene group - or -OCO- alkylene group - is more preferable.

W represents an organic group containing a cyclic structure. Among them, a cyclic organic group is preferable.
Examples of the cyclic organic group include an alicyclic group, an aryl group, and a heterocyclic group.
The alicyclic group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic group include a monocyclic cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic group include polycyclic cycloalkyl groups such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group. Above all, an alicyclic group having a bulky structure having 7 or more carbon atoms such as a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group, and an adamantyl group is subjected to a PEB (heating after exposure) step. It is preferable from the viewpoints of suppressing the diffusivity in the film and improving MEEF (Mask Error Enhancement Factor).

The aryl group may be monocyclic or polycyclic. Examples of the aryl group include a phenyl group, a naphthyl group, a phenanthryl group and an anthryl group. Among them, a naphthyl group having a relatively low light absorbance at 193 nm is preferable.
The heterocyclic group may be monocyclic or polycyclic, but polycyclic is more capable of suppressing acid diffusion. Further, the heterocyclic group may have aromaticity or may not have aromaticity. Examples of the aromatic heterocyclic ring include a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Examples of the heterocyclic ring having no aromaticity include a tetrahydropyran ring, a lactone ring, a sultone ring, and a decahydroisoquinoline ring. As the heterocyclic ring in the heterocyclic group, a furan ring, a thiophene ring, a pyridine ring or a decahydroisoquinoline ring is particularly preferred. Examples of the lactone ring and the sultone ring include the lactone structure and the sultone structure exemplified in the aforementioned resin.

  The cyclic organic group may have a substituent. Examples of the substituent include an alkyl group (which may be straight-chain or branched, and preferably has 1 to 12 carbon atoms) and a cycloalkyl group (which may be any of a monocyclic, polycyclic, and spiro ring). Often having 3 to 20 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), a hydroxyl group, an alkoxy group, an ester group, an amide group, a urethane group, a ureido group, a thioether group, a sulfonamide group, and a sulfonic acid. Ester groups are mentioned. The carbon constituting the cyclic organic group (carbon contributing to ring formation) may be a carbonyl carbon.

o represents an integer of 1 to 3. p represents an integer of 0 to 10. q represents an integer of 0 to 10.
In one embodiment, it is preferable that in the general formula (3), o is an integer of 1 to 3, p is an integer of 1 to 10, and q is 0. Xf is preferably a fluorine atom, R ₄ and R ₅ are preferably both hydrogen atoms, and W is preferably a polycyclic hydrocarbon group. o is more preferably 1 or 2, and still more preferably 1. p is more preferably an integer of 1 to 3, furthermore preferably 1 or 2, and particularly preferably 1. W is more preferably a polycyclic cycloalkyl group, even more preferably an adamantyl group or a diamantyl group.
In the general formula (3), as a partial structure other than ^{_{W, SO 3 - -CF 2 -CH}} 2 -OCO-, SO 3 - -CF 2 -CHF-CH 2 -OCO-, SO 3 - -CF 2 ^{_{-COO-, SO 3 - -CF 2 -CF}} 2 -CH 2 -, SO 3 - -CF 2 -CH (CF 3) -OCO- it is mentioned as preferred.

(Cation)
In the general formula (3), X ⁺ represents a cation.
X ⁺ is not particularly limited as long as it is a cation, but preferred embodiments include, for example, cations (parts other than Z ⁻ ) in general formulas (ZI), (ZII) and (ZIII) described below.

(Preferred embodiment)
Preferred embodiments of the specific photoacid generator include, for example, compounds represented by the following general formulas (ZI), (ZII) and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represent an organic group.
The organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ generally has 1 to 30, preferably 1 to 20 carbon atoms.
Two of R _{201 to} R ₂₀₃ may be bonded to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond, or a carbonyl group. Examples of the group formed by combining two of R _{201 to} R ₂₀₃ include an alkylene group (for example, a butylene group and a pentylene group).
Z ⁻ represents an anion in the general formula (3), and specifically represents the following anion.

Examples of the organic groups represented by R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include, for example, corresponding groups in compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4) described later. Can be mentioned.
Note that a compound having a plurality of structures represented by the general formula (ZI) may be used. For example, at least one of R _{201 to} R ₂₀₃ of the compound represented by the general formula (ZI) is combined with at least one of R _{201 to} R ₂₀₃ of another compound represented by the general formula (ZI) by a single bond or It may be a compound having a structure linked via a linking group.

  More preferred components (ZI) include compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4) described below.

First, compound (ZI-1) will be described.
The compound (ZI-1) is an arylsulfonium compound in which at least one of R _{201 to} R _{203 in} the general formula (ZI) is an aryl group, that is, a compound having arylsulfonium as a cation.
In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group, and the remainder may be an alkyl group or a cycloalkyl group.
Examples of the arylsulfonium compound include a triarylsulfonium compound, a diarylalkylsulfonium compound, an aryldialkylsulfonium compound, a diarylcycloalkylsulfonium compound, and an aryldicycloalkylsulfonium compound.

The aryl group of the arylsulfonium compound is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, and the like. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue, a benzothiophene residue, and the like. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.
The alkyl group or cycloalkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms and a cycloalkyl group having 3 to 15 carbon atoms, for example, a methyl group, Examples thereof include an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group and cycloalkyl group of R _{201 to} R ₂₀₃ are an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), and an aryl group (for example, having 6 to 14 carbon atoms). , An alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, or a phenylthio group as a substituent.

Next, the compound (ZI-2) will be described.
Compound (ZI-2) is a compound in which R _{201 to} R ₂₀₃ in formula (ZI) each independently represent an organic group having no aromatic ring. Here, the aromatic ring includes an aromatic ring containing a hetero atom.
The organic group containing no aromatic ring as R _{201 to} R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.
R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, and more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxy group. A carbonylmethyl group, particularly preferably a straight-chain or branched 2-oxoalkyl group.

As the alkyl group and cycloalkyl group of R _{201 to} R ₂₀₃ , preferably, a linear or branched alkyl group having 1 to 10 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group), carbon atom Cycloalkyl groups (cyclopentyl group, cyclohexyl group, norbornyl group) of 3 to 10 can be exemplified.
R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

Next, the compound (ZI-3) will be described.
The compound (ZI-3) is a compound represented by the following formula (ZI-3) and a compound having a phenacylsulfonium salt structure.

In the general formula (ZI-3),
R _{1c to} R _5c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group. , A nitro group, an alkylthio group or an arylthio group.
R _6c and R _7c each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an aryl group.
R _x and R _y each independently represent an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonylalkyl group, an allyl group, or a vinyl group.

Any two or more of R _{1c to} R _5c , R _5c and R _6c , R _6c and R _7c , R _5c and R _x , and R _x and R _y may combine to form a ring structure. Often, this ring structure may contain an oxygen atom, a sulfur atom, a ketone group, an ester bond, and an amide bond.
Examples of the ring structure include an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic hetero ring, and a polycyclic fused ring in which two or more of these rings are combined. Examples of the ring structure include a 3- to 10-membered ring, preferably a 4- to 8-membered ring, and more preferably a 5- or 6-membered ring.

Examples of the group formed by combining any two or more of R _{1c to} R _5c , R _6c and R _7c , and R _x and R _y include a butylene group and a pentylene group.
The group formed by combining R _5c and R _6c , and R _5c and R _x is preferably a single bond or an alkylene group, and examples of the alkylene group include a methylene group and an ethylene group. .
Zc ^- represents an anion of the general formula (3), specifically, as described above.

Specific examples of the alkoxy group in the alkoxycarbonyl group as R _1c to R _5c are the same as specific examples of the alkoxy group as the _R 1c _{to R 5c.}
Specific examples of the alkyl group in the alkylcarbonyloxy group and alkylthio group as R _1c to R _5c are the same as specific examples of the alkyl group of the _R 1c _{to R 5c.}
Specific examples of the cycloalkyl group in the cycloalkyl carbonyl group as R _1c to R _5c are the same as specific examples of the cycloalkyl group of the _R 1c _{to R 5c.}
Specific examples of the aryl group in the aryloxy group and arylthio group as R _1c to R _5c are the same as specific examples of the aryl group of the _R 1c _{to R 5c.}

  Examples of the cation in the compound (ZI-2) or (ZI-3) in the present invention include cations described in paragraphs [0036] and after of US Patent Application Publication No. 2012/0076996.

Next, the compound (ZI-4) will be described.
Compound (ZI-4) is represented by the following general formula (ZI-4).

In the general formula (ZI-4),
R ₁₃ represents a group having a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, or a cycloalkyl group. These groups may have a substituent.
R ₁₄ is a group having a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group having a cycloalkyl group, when a plurality of groups are present, Represents These groups may have a substituent.
R ₁₅ each independently represents an alkyl group, a cycloalkyl group or a naphthyl group. These groups may have a substituent. Two R _{15 s} may combine with each other to form a ring. When two R ₁₅ are bonded to each other to form a ring, the ring skeleton may contain a hetero atom such as an oxygen atom or a nitrogen atom. In one aspect, it is preferred that two R ₁₅ are alkylene groups and combine with each other to form a ring structure.
l represents an integer of 0 to 2.
r represents an integer of 0 to 8.
Z ⁻ represents an anion in the general formula (3), and is specifically as described above.

In the general formula (ZI-4), the alkyl group for R ₁₃ , R _14, and R ₁₅ is linear or branched, and preferably has 1 to 10 carbon atoms, and is preferably a methyl group, an ethyl group, or an n group. -Butyl group, t-butyl group and the like are preferred.
Examples of the cation of the compound represented by the general formula (ZI-4) in the present invention include paragraphs [0121], [0123], and [0124] of JP-A-2010-256842, and JP-A-2011-76056. The cations described in paragraphs [0127], [0129], and [0130] can be used.

Next, general formulas (ZII) and (ZIII) will be described.
In formulas (ZII) and (ZIII), R _{204 to} R ₂₀₇ each independently represent an aryl group, an alkyl group, or a cycloalkyl group.
The aryl group represented by R _{204 to} R ₂₀₇ is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. The aryl group of R _{204 to} R ₂₀₇ may be an aryl group having a heterocyclic structure having an oxygen atom, a nitrogen atom, a sulfur atom, and the like. Examples of the skeleton of the aryl group having a heterocyclic structure include pyrrole, furan, thiophene, indole, benzofuran, and benzothiophene.
As the alkyl group and cycloalkyl group for R _{204 to} R ₂₀₇ , preferably a linear or branched alkyl group having 1 to 10 carbon atoms (eg, methyl, ethyl, propyl, butyl, pentyl), carbon Cycloalkyl groups (cyclopentyl group, cyclohexyl group, norbornyl group) of 3 to 10 can be exemplified.

The aryl group, alkyl group, and cycloalkyl group of R _{204 to} R ₂₀₇ may have a substituent. Examples of the substituent which the aryl group, alkyl group and cycloalkyl group of R _{204 to} R ₂₀₇ may have include, for example, an alkyl group (for example, having 1 to 15 carbon atoms) and a cycloalkyl group (for example, having 3 to 15 carbon atoms). ), An aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.
Z ⁻ represents an anion in the general formula (3), and is specifically as described above.

The photoacid generator (including the specific photoacid generator; the same applies hereinafter) may be in the form of a low-molecular compound or may be in a form incorporated in a part of the polymer. Further, the form of the low molecular compound and the form incorporated in a part of the polymer may be used in combination.
When the photoacid generator is in the form of a low-molecular compound, the molecular weight is preferably 580 or more, more preferably 600 or more, still more preferably 620 or more, and particularly preferably 640 or more. preferable. The upper limit is not particularly limited, but is preferably 3000 or less, more preferably 2000 or less, and still more preferably 1000 or less.
When the photoacid generator is in a form incorporated in a part of the polymer, it may be incorporated in a part of the resin described above or in a resin different from the resin.
The photoacid generator can be synthesized by a known method, for example, according to the method described in JP-A-2007-161707.
The photoacid generator can be used alone or in combination of two or more.
The content of the photoacid generator in the composition (when a plurality of types are present, the total thereof) is preferably 0.1 to 30% by mass, more preferably 0.5 to 30% by mass, based on the total solid content of the composition. It is 25% by mass, more preferably 3 to 20% by mass, particularly preferably 3 to 15% by mass.
When the compound represented by the above general formula (ZI-3) or (ZI-4) is included as the photoacid generator, the content of the photoacid generator contained in the composition (when a plurality of types are present, the 1.5 to 35% by mass, more preferably 5 to 35% by mass, still more preferably 8 to 30% by mass, and still more preferably 9 to 30% by mass, based on the total solid content of the composition. Preferably, 9 to 25% by mass is particularly preferred.

[3] Acid Diffusion Control Agent The resist composition of the present invention preferably contains an acid diffusion control agent. The acid diffusion controller acts as a quencher that traps an acid generated from a photoacid generator or the like at the time of exposure and suppresses the reaction of the acid-decomposable resin in the unexposed area due to the excess generated acid. As the acid diffusion controller, a basic compound, a low-molecular compound having a nitrogen atom and having a group capable of leaving by the action of an acid, a basic compound whose basicity decreases or disappears upon irradiation with actinic rays or radiation, or Alternatively, an onium salt that becomes a weak acid relatively to the photoacid generator can be used.

  Preferred examples of the basic compound include compounds having structures represented by the following formulas (A) to (E).

In the general formulas (A) and (E),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different, and represent a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (having a carbon number of 1 to 20). 6 to 20), wherein R ²⁰¹ and R ²⁰² may be bonded to each other to form a ring.
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and represent an alkyl group having 1 to 20 carbon atoms.

Regarding the alkyl group, the alkyl group having a substituent is preferably an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a cyanoalkyl group having 1 to 20 carbon atoms.
The alkyl groups in these general formulas (A) and (E) are more preferably unsubstituted.

Preferred compounds include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, piperidine and the like, and more preferred compounds are imidazole structure, diazabicyclo structure, onium hydroxide structure, onium carboxylate. Examples thereof include a compound having a structure, a trialkylamine structure, an aniline structure or a pyridine structure, an alkylamine derivative having a hydroxyl group and / or an ether bond, and an aniline derivative having a hydroxyl group and / or an ether bond.
Specific examples of preferred compounds include the compounds exemplified in US 2012/0219913 A1 [0379].
Preferred basic compounds further include an amine compound having a phenoxy group, an ammonium salt compound having a phenoxy group, an amine compound having a sulfonic acid ester group, and an ammonium salt compound having a sulfonic acid ester group.
One of these basic compounds may be used alone, or two or more of them may be used in combination.

The resist composition of the present invention may or may not contain a basic compound. If it does, the content of the basic compound is usually 0.001 to 10 based on the solid content of the composition. % By mass, preferably 0.01 to 5% by mass.
The ratio of the photoacid generator and the basic compound used in the composition is preferably photoacid generator / basic compound (molar ratio) = 2.5 to 300, more preferably 5.0 to 200, and still more preferably. 7.0 to 150.

Low molecular weight compounds having a nitrogen atom and having a group capable of leaving by the action of an acid (hereinafter also referred to as “compound (C)”) are amine derivatives having a group capable of leaving by the action of an acid on the nitrogen atom. It is preferred that
As the group leaving by the action of an acid, an acetal group, a carbonate group, a carbamate group, a tertiary ester group, a tertiary hydroxyl group, and a hemiaminal ether group are preferable, and a carbamate group and a hemiaminal ether group are particularly preferable. .
The molecular weight of the compound (C) is preferably from 100 to 1,000, more preferably from 100 to 700, and particularly preferably from 100 to 500.
Compound (C) may have a carbamate group having a protecting group on the nitrogen atom. The protecting group constituting the carbamate group can be represented by the following general formula (d-1).

In the general formula (d-1),
Rb is each independently a hydrogen atom, an alkyl group (preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferably having 3 to 30 carbon atoms), an aryl group (preferably having 3 to 30 carbon atoms), or an aralkyl group ( Preferably represents 1 to 10 carbon atoms) or an alkoxyalkyl group (preferably 1 to 10 carbon atoms). Rb may be mutually connected to form a ring.
The alkyl group, cycloalkyl group, aryl group, and aralkyl group represented by Rb are substituted with a hydroxyl group, a cyano group, an amino group, a pyrrolidino group, a piperidino group, a morpholino group, a functional group such as an oxo group, an alkoxy group, or a halogen atom. May be. The same applies to the alkoxyalkyl group represented by Rb.

Rb is preferably a linear or branched alkyl group, cycloalkyl group, or aryl group. More preferably, it is a linear or branched alkyl group or cycloalkyl group.
Examples of the ring formed by two Rb's being connected to each other include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic hydrocarbon group, and derivatives thereof.
As a specific structure of the group represented by the general formula (d-1), a structure disclosed in US2012 / 0135348 A1 [0466] can be mentioned, but it is not limited thereto.

  It is particularly preferable that the compound (C) has a structure represented by the following general formula (6).

In the general formula (6), Ra represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group. When 1 is 2, the two Ras may be the same or different, and the two Ras may be mutually connected to form a heterocyclic ring with the nitrogen atom in the formula. The heterocycle may contain a hetero atom other than the nitrogen atom in the formula.
Rb has the same meaning as Rb in formula (d-1), and preferred examples are also the same.
l represents an integer of 0 to 2, m represents an integer of 1 to 3, and satisfies l + m = 3.
In the general formula (6), the alkyl group, cycloalkyl group, aryl group and aralkyl group as Ra are described above as the group which may be substituted with the alkyl group, cycloalkyl group, aryl group and aralkyl group as Rb. It may be substituted with the same group as the group.

Specific examples of the alkyl group, cycloalkyl group, aryl group, and aralkyl group of Ra (these alkyl group, cycloalkyl group, aryl group, and aralkyl group may be substituted with the above group) include: As Rb, the same groups as in the specific examples described above can be mentioned.
Specific examples of the particularly preferred compound (C) in the present invention include, but are not limited to, the compounds disclosed in US 2012/0135348 A1 [0475].

The compound represented by the general formula (6) can be synthesized based on JP-A-2007-298569, JP-A-2009-199021, and the like.
In the present invention, the low molecular weight compound (C) having a group capable of leaving by the action of an acid on the nitrogen atom can be used alone or in combination of two or more.
The content of the compound (C) in the resist composition of the present invention is preferably 0.001 to 20% by mass, more preferably 0.001 to 10% by mass, based on the total solid content of the composition. More preferably, it is 0.01 to 5% by mass.

  A basic compound whose basicity decreases or disappears upon irradiation with actinic rays or radiation (hereinafter, also referred to as “compound (PA)”) has a proton acceptor functional group, and is irradiated with actinic rays or radiation. Is a compound whose proton acceptor property is reduced or disappears or changes from proton acceptor property to acidic.

  The proton acceptor functional group is a group having an electron capable of interacting electrostatically with a proton or a functional group having an electron, for example, a functional group having a macrocyclic structure such as a cyclic polyether, or a π conjugate. A functional group having a nitrogen atom with an unshared electron pair that does not contribute. The nitrogen atom having a lone pair that does not contribute to π conjugation is, for example, a nitrogen atom having a partial structure represented by the following formula.

  Preferred partial structures of the proton acceptor functional group include, for example, crown ether, azacrown ether, primary to tertiary amine, pyridine, imidazole, and pyrazine structures.

The compound (PA) is decomposed by irradiation with actinic rays or radiation to generate a compound in which the proton acceptor property has been reduced or eliminated, or the proton acceptor property has been changed to acidic. Here, the decrease, disappearance, or change from the proton acceptor property to the acidic property of the proton acceptor property is a change in the proton acceptor property due to the addition of a proton to the proton acceptor functional group. Means that when a proton adduct is formed from a compound having a proton acceptor functional group (PA) and a proton, the equilibrium constant in the chemical equilibrium thereof decreases.
The proton acceptor property can be confirmed by performing pH measurement.

  In the present invention, the compound generated by decomposition of the compound (PA) upon irradiation with actinic rays or radiation preferably has an acid dissociation constant pKa satisfying pKa <−1, more preferably −13 <pKa <−1. And more preferably −13 <pKa <−3.

  In the present invention, the acid dissociation constant pKa means the acid dissociation constant pKa in an aqueous solution, for example, Chemical Handbook (II) (revised 4th edition, 1993, edited by The Chemical Society of Japan, Maruzen Co., Ltd.) The lower the value, the higher the acid strength. Specifically, the acid dissociation constant pKa in an aqueous solution can be actually measured by measuring the acid dissociation constant at 25 ° C. using an infinitely diluted aqueous solution. Can be determined by calculation. All the pKa values described in this specification indicate values calculated by using this software package.

  Software Package 1: Advanced Chemistry Development (ACD / Labs) Software V8.14 for Solaris (1994-2007 ACD / Labs).

  The compound (PA) generates, for example, a compound represented by the following general formula (PA-1) as the above-mentioned protonated product generated by decomposition upon irradiation with actinic rays or radiation. The compound represented by the general formula (PA-1) has an acidic group together with a proton-accepting functional group, so that the proton-accepting property decreases, disappears, or decreases from the proton-accepting property as compared with the compound (PA). It is a compound that has changed to acidic.

In the general formula (PA-1),
Q _represents -SO 3 H, _-CO 2 H, or _-W 1 _NHW 2 _{R f.} Here, R _f represents an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 to 30 carbon atoms), and W ₁ and W _{1 2,} each independently, -SO ₂ - represents a or -CO-.
A represents a single bond or a divalent linking group.
X is, -SO ₂ - represents a or -CO-.
n represents 0 or 1.
B represents a single bond, an oxygen atom, or -N _(R x) R _y - represents a. Here, _Rx represents a hydrogen atom or a monovalent organic group, and _Ry represents a single bond or a divalent organic group. R _x may be bonded to R _y to form a ring, or may be bonded to R to form a ring.
R represents a monovalent organic group having a proton acceptor functional group.

  The compound (PA) is preferably an ionic compound. The proton acceptor functional group may be contained in either the anion portion or the cation portion, but is preferably contained in the anion portion.

  In the present invention, a compound (PA) other than the compound generating the compound represented by the general formula (PA-1) can also be appropriately selected. For example, an ionic compound having a proton acceptor site in the cation portion may be used. More specifically, a compound represented by the following general formula (7) is exemplified.

In the formula, A represents a sulfur atom or an iodine atom.
m represents 1 or 2, and n represents 1 or 2. However, when A is a sulfur atom, m + n = 3, and when A is an iodine atom, m + n = 2.
R represents an aryl group.
R _N represents an aryl group substituted with a proton acceptor functional group. X ^- represents a counter anion.
Specific examples of X ⁻ include the same as the anion of the photoacid generator described above.
Specific examples of the aryl group of R and R _N is a phenyl group are preferably exemplified.

Specific examples of the proton acceptor functional group R _N are the same as those of the proton acceptor functional group described in the foregoing formula (PA-1).
Hereinafter, specific examples of the ionic compound having a proton acceptor site in the cation portion include the compounds exemplified in US2011 / 0269072A1 [0291].
In addition, such a compound can be synthesized with reference to the methods described in, for example, JP-A-2007-230913 and JP-A-2009-122623.

As the compound (PA), one type may be used alone, or two or more types may be used in combination.
The content of the compound (PA) is preferably from 0.1 to 10% by mass, more preferably from 1 to 8% by mass, based on the total solid content of the composition.

In the resist composition of the present invention, an onium salt that becomes a weak acid relatively to the photoacid generator can be used as an acid diffusion controller.
When a photoacid generator and an onium salt that generates an acid that is a relatively weak acid with respect to the acid generated from the photoacid generator are used in a mixture, the photoacid generator is activated by irradiation with actinic rays or radiation. When the generated acid collides with an unreacted onium salt having a weak acid anion, the weak acid is released by salt exchange to produce an onium salt having a strong acid anion. In this process, the strong acid is exchanged for a weak acid having a lower catalytic ability, so that the acid is apparently deactivated and the acid diffusion can be controlled.

  As the onium salt that becomes a relatively weak acid with respect to the photoacid generator, compounds represented by the following general formulas (d1-1) to (d1-3) are preferable.

In the formula, R ⁵¹ is a hydrocarbon group which may have a substituent, and Z ^2c is a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent (provided that carbon atoms adjacent to S , A fluorine atom is not substituted), R ⁵² is an organic group, Y ³ is a linear, branched or cyclic alkylene group or an arylene group, and Rf is a fluorine atom. And each M ⁺ is independently a sulfonium or iodonium cation.

Preferred examples of the sulfonium cation or iodonium cation represented by M ⁺ include a sulfonium cation exemplified by the general formula (ZI) and an iodonium cation exemplified by the general formula (ZII).

Preferred examples of the anion portion of the compound represented by the general formula (d1-1) include a structure exemplified in paragraph [0198] of JP-A-2012-242799.
Preferred examples of the anion moiety of the compound represented by the general formula (d1-2) include a structure exemplified in paragraph [0201] of JP-A-2012-242799.
Preferred examples of the anion portion of the compound represented by the general formula (d1-3) include the structures exemplified in paragraphs [0209] and [0210] of JP-A-2012-242799.

The onium salt which becomes a relatively weak acid with respect to the photoacid generator is (C) a compound having a cation site and an anion site in the same molecule, and wherein the cation site and the anion site are linked by a covalent bond. (Hereinafter, also referred to as “compound (CA)”).
The compound (CA) is preferably a compound represented by any of the following formulas (C-1) to (C-3).

In the general formulas (C-1) to (C-3),
R ₁ , R ₂ and R ₃ represent a substituent having 1 or more carbon atoms.
L ₁ represents a divalent linking group or a single bond linking the cation site and the anion site.
-X ^{- is,} -COO _^-, -SO 3 _- represents an anion portion selected from ^{_{-R 4 -, -SO 2 -,}} -N. R ₄ has a carbonyl group: —C (＝ O) —, a sulfonyl group: —S (＝ O) ₂ —, and a sulfinyl group: —S (＝ O) — at a linking site with an adjacent N atom. Represents a valent substituent.
R ₁ , R ₂ , R ₃ , R ₄ , and L ₁ may combine with each other to form a ring structure. In (C-3), two of R _{1 to} R ₃ may be combined to form a double bond with an N atom.

Examples of the substituent having 1 or more carbon atoms in R _{1 to} R ₃ include an alkyl group, a cycloalkyl group, an aryl group, an alkyloxycarbonyl group, a cycloalkyloxycarbonyl group, an aryloxycarbonyl group, an alkylaminocarbonyl group, and a cycloalkylamino. Examples include a carbonyl group and an arylaminocarbonyl group. Preferably, they are an alkyl group, a cycloalkyl group, and an aryl group.

L ₁ as a divalent linking group includes a linear or branched alkylene group, a cycloalkylene group, an arylene group, a carbonyl group, an ether bond, an ester bond, an amide bond, a urethane bond, a urea bond, and a mixture of these two types. Examples include groups obtained by combining the above. L ₁ is more preferably an alkylene group, an arylene group, an ether bond, an ester bond, or a group formed by combining two or more of these.
Preferred examples of the compound represented by the general formula (C-1) include paragraphs [0037] to [0039] of JP-A-2013-6827 and paragraphs [0027] to [0029] of JP-A-2013-8020. ] Can be mentioned.
Preferred examples of the compound represented by the general formula (C-2) include the compounds exemplified in paragraphs [0012] to [0013] of JP-A-2012-189977.
Preferred examples of the compound represented by the general formula (C-3) include the compounds exemplified in paragraphs [0029] to [0031] of JP-A-2012-252124.

  The content of the onium salt which becomes a relatively weak acid with respect to the photoacid generator is preferably 0.5 to 10.0% by mass, and more preferably 0.5 to 8.0% by mass based on the solid content of the composition. %, More preferably 1.0 to 8.0% by mass.

[4] Solvent The resist composition of the present invention usually contains a solvent.
Solvents that can be used when preparing the composition include, for example, alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate, alkyl alkoxypropionate, cyclic lactone (preferably having 4 to 4 carbon atoms). 10), an organic solvent such as a monoketone compound (preferably having 4 to 10 carbon atoms) which may have a ring, an alkylene carbonate, an alkyl alkoxyacetate and an alkyl pyruvate.
Specific examples of these solvents include those described in U.S. Patent Application Publication No. 2008/0187860 [0441] to [0455].

In the present invention, a mixed solvent obtained by mixing a solvent having a hydroxyl group in the structure with a solvent having no hydroxyl group may be used as the organic solvent.
As the solvent containing a hydroxyl group and the solvent not containing a hydroxyl group, the above-mentioned exemplified compounds can be appropriately selected. As the solvent containing a hydroxyl group, alkylene glycol monoalkyl ether, alkyl lactate and the like are preferable, and propylene glycol monomethyl ether ( PGME (also known as 1-methoxy-2-propanol), ethyl lactate, and methyl 2-hydroxyisobutyrate are more preferred. Further, as the solvent containing no hydroxyl group, alkylene glycol monoalkyl ether acetate, alkyl alkoxy propionate, a monoketone compound which may contain a ring, a cyclic lactone, an alkyl acetate and the like are preferable, and among these, propylene glycol monomethyl ether is preferable. Acetate (PGMEA, also known as 1-methoxy-2-acetoxypropane), ethylethoxypropionate, 2-heptanone, γ-butyrolactone, cyclohexanone, and butyl acetate are particularly preferred, and propylene glycol monomethyl ether acetate, ethylethoxypropionate, -Heptanone is most preferred.
The mixing ratio (mass) of the solvent containing a hydroxyl group to the solvent not containing a hydroxyl group is 1/99 to 99/1, preferably 10/90 to 90/10, and more preferably 20/80 to 60/40. . A mixed solvent containing 50% by mass or more of a solvent containing no hydroxyl group is particularly preferable in view of coating uniformity.
The solvent preferably contains propylene glycol monomethyl ether acetate, and is preferably a single solvent of propylene glycol monomethyl ether acetate or a mixed solvent of two or more kinds containing propylene glycol monomethyl ether acetate.

[5] Surfactant The resist composition of the present invention may or may not further contain a surfactant, and if so, a fluorine-based and / or silicon-based surfactant (fluorine-based surfactant, silicon-based Or a surfactant having both a fluorine atom and a silicon atom).

When the resist composition of the present invention contains a surfactant, it is possible to provide a resist pattern with good sensitivity and resolution, low adhesion and little development defects when using an exposure light source of 250 nm or less, particularly 220 nm or less. Becomes
Examples of the fluorine-based and / or silicon-based surfactants include surfactants described in paragraph [0276] of US Patent Application Publication No. 2008/0248425.
In the present invention, a surfactant other than the fluorine-based and / or silicon-based surfactant described in paragraph [0280] of US Patent Application Publication No. 2008/0248425 can also be used.

These surfactants may be used alone or in some combination.
When the resist composition of the present invention contains a surfactant, the amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.0005 to 2% by mass based on the total solid content of the composition. 1% by mass.

[6] Other Additives The resist composition of the present invention may or may not contain an onium carboxylate. Examples of such an onium carboxylate include those described in U.S. Patent Application Publication No. 2008/0187860 [0605] to [0606].
These onium carboxylate salts can be synthesized by reacting sulfonium hydroxide, iodonium hydroxide, ammonium hydroxide and carboxylic acid with silver oxide in a suitable solvent.

When the resist composition of the present invention contains an onium carboxylate, the content is generally from 0.1 to 20% by mass, preferably from 0.5 to 10% by mass, based on the total solid content of the composition. %, More preferably 1 to 7% by mass.
The resist composition of the present invention may further contain, if necessary, an acid multiplying agent, a dye, a plasticizer, a photosensitizer, a light absorbing agent, an alkali-soluble resin, a dissolution inhibitor, and a compound that promotes solubility in a developer. (For example, a phenol compound having a molecular weight of 1,000 or less, an alicyclic or aliphatic compound having a carboxyl group) and the like.

Such a phenol compound having a molecular weight of 1,000 or less can be obtained by, for example, referring to the methods described in JP-A-4-122938, JP-A-2-28531, U.S. Pat. No. 4,916,210, and EP 219294. Thus, it can be easily synthesized by those skilled in the art.
Specific examples of the alicyclic group having a carboxyl group, or an aliphatic compound include carboxylic acid derivatives having a steroid structure such as cholic acid, deoxycholic acid, and lithocholic acid, adamantanecarboxylic acid derivatives, adamantanedicarboxylic acid, cyclohexanecarboxylic acid, and cyclohexane. Examples include, but are not limited to, dicarboxylic acids.

The solid content concentration of the resist composition of the present invention is usually 1.0 to 20% by mass, preferably 2.0 to 15% by mass, and more preferably 2.0 to 10% by mass. When the solid content concentration is in the above range, the resist solution can be uniformly applied on the substrate, and a resist pattern excellent in line width roughness can be formed. Although the reason is not clear, it is probable that by setting the solid content concentration to 20% by mass or less, aggregation of the material, particularly the photoacid generator, in the resist solution is suppressed, and as a result, a uniform resist film is formed. It is considered that was formed.
The solid content concentration is a weight percentage of the weight of the other resist components excluding the solvent with respect to the total weight of the composition.

  The method for preparing the resist composition of the present invention is not particularly limited, but it is preferable to dissolve each of the above-described components in a predetermined organic solvent, preferably the above-mentioned mixed solvent, and to filter the solution. The pore size of the filter used for filter filtration is preferably 0.1 μm or less, more preferably 0.05 μm or less, and still more preferably 0.03 μm or less, made of polytetrafluoroethylene, polyethylene, or nylon. In filter filtration, for example, as in JP-A-2002-62667, circulating filtration may be performed, or filtration may be performed by connecting a plurality of types of filters in series or in parallel. The composition may be filtered a plurality of times. Further, the composition may be subjected to a degassing treatment before and after the filtration.

[Procedure of step (2)]
Although the procedure of the step (2) is not particularly limited, a method of applying the resist composition on the resist underlayer film and performing a curing treatment as necessary (coating method) or forming a resist film on the temporary support Then, a method of transferring a resist film onto a substrate may be used. Among them, the coating method is preferred from the viewpoint of excellent productivity.

[Resist film]
The thickness of the resist film is 1 μm or less, more preferably 700 nm or less, and further preferably 500 nm or less for the above-described reason.
Further, the thickness of the resist film is preferably 1 nm or more, more preferably 10 nm or more, and further preferably 100 nm or more. Such a film thickness can be obtained by setting the solid content concentration in the composition to an appropriate range, imparting an appropriate viscosity, and improving coatability and film forming property.

  An adhesion auxiliary layer may be provided between the resist underlayer film and the resist film for the purpose of reducing peeling and falling of the resist pattern.

  As a method of forming the adhesion auxiliary layer, a method of forming an adhesion auxiliary layer having a polymerizable group on the resist underlayer film is preferably exemplified. The polymerizable group in the adhesion assisting layer formed by the present method forms a chemical or physical bond between the resist underlayer film and the resist film. It is considered that excellent adhesion is exhibited.

The adhesion auxiliary layer preferably has a polymerizable group. More specifically, it is preferable that the material (particularly, preferably a resin) forming the adhesion auxiliary layer has a polymerizable group.
Although the type of the polymerizable group is not particularly limited, for example, (meth) acryloyl group, epoxy group, oxetanyl group, maleimide group, itaconic ester group, crotonic ester group, isocrotonic ester group, maleic ester group, styryl group , A vinyl group, an acrylamide group, and a methacrylamide group. Among them, a (meth) acryloyl group, an epoxy group, an oxetanyl group, and a maleimide group are preferable, and a (meth) acryloyl group is more preferable.

  The thickness of the adhesion auxiliary layer is not particularly limited, but is preferably 1 to 100 nm, more preferably 1 to 50 nm, and more preferably 1 to 10 nm, because a more precise fine pattern can be formed. More preferably, it is particularly preferably 1 to 5 nm.

The method for forming the adhesion auxiliary layer is not particularly limited, but a method for applying the composition for forming an adhesion auxiliary layer on a resist underlayer film and subjecting the composition to a curing treatment as needed to form the adhesion auxiliary layer ( Coating method) or a method of forming an adhesion auxiliary layer on a temporary support and transferring the adhesion auxiliary layer onto a resist underlayer film. Among them, the coating method is preferred from the viewpoint of excellent productivity.
The method of applying the composition for forming an adhesion auxiliary layer on the resist underlayer film is not particularly limited, and a known method can be used. In the field of semiconductor manufacturing, spin coating is preferably used.

  After applying the composition for forming an adhesion auxiliary layer on the resist underlayer film, a curing treatment may be performed, if necessary. The curing treatment is not particularly limited, and examples thereof include an exposure treatment and a heat treatment.

For the exposure processing, light irradiation with a UV lamp, visible light, or the like is used. Examples of the light source include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of the radiation include an electron beam, an X-ray, an ion beam, and a far infrared ray. Specific examples include scanning exposure with an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, and infrared lamp exposure.
The exposure time varies depending on the reactivity of the polymer and the light source, but is usually between 10 seconds and 5 hours. The exposure energy may be about 10 to 10000 mJ / cm ^2, preferably in the range of 100~8000mJ / cm ^2.
In the case of using heat treatment, a blow dryer, an oven, an infrared dryer, a heating drum, or the like can be used.
The exposure treatment and the heat treatment may be combined.

[Step (3): exposure step]
Step (3) is a step of irradiating (exposure) actinic rays or radiation to the film (resist film) formed in step (2).

  As described above, the thickness of the resist film is set to 1 μm or less, and the thickness is set to be small. Therefore, light at the time of exposure is hardly absorbed by the resin or the like in the resist film, and light easily reaches the bottom of the exposed portion. As a result, the present invention has an advantage that the exposure sensitivity of the resist film is high.

The light used for exposure is not particularly limited, and examples thereof include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-ray, and electron beam. Far ultraviolet light having a wavelength of preferably 250 nm or less, more preferably 220 nm or less, and still more preferably 1 to 200 nm.
More specifically, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (157 nm), X-ray, EUV (13 nm), electron beam and the like are mentioned. It is preferably an ArF excimer laser, EUV or an electron beam, more preferably a KrF excimer laser or an ArF excimer laser, and further preferably a KrF excimer laser.

  In the exposure step, a liquid immersion exposure method can be applied. The immersion exposure method can be combined with a super-resolution technique such as a phase shift method and a modified illumination method. The immersion exposure can be performed, for example, according to the method described in paragraphs [0594] to [0601] of JP-A-2013-2422397.

  In step (3), the resist film is preferably exposed by one of KrF exposure, ArF exposure, and ArF immersion exposure, and is preferably exposed by KrF exposure.

After the step (3) and before the step (4) to be described later, the film irradiated (irradiated) with the actinic ray or the radiation in the step (3) may be subjected to a heat treatment (PEB: Post Exposure Bake). Good. This step promotes the reaction of the exposed part. The heat treatment (PEB) may be performed plural times.
The temperature of the heat treatment is preferably from 70 to 130 ° C, more preferably from 80 to 120 ° C.
The time of the heat treatment is preferably from 30 to 300 seconds, more preferably from 30 to 180 seconds, and further preferably from 30 to 90 seconds.
The heat treatment can be performed by means provided in a usual exposure / developing machine, and may be performed using a hot plate or the like.

[Step (4): developing step]
The step (4) is a step of developing the film (exposed) irradiated with the actinic ray or radiation in the step (3) to form a resist pattern.

As a preferred embodiment of the resist pattern, a resist pattern having a line portion having a line width of 5000 nm or less can be mentioned. In this embodiment, the line width of the line portion is more preferably 1000 nm or less, and further preferably 500 nm or less. The line width of the line portion is usually 10 nm or more.
When a resist pattern having a line portion having a line width in such a range is formed, the cross-sectional shape of a pattern (final pattern) finally obtained after the step (5) has a vertically long shape (that is, a shape having a large aspect ratio). ). In general, a pattern having a vertically long cross section tends to fall easily.However, the present invention forms a final pattern having a line portion having a line width in the above range because the resist underlayer film pattern hardly falls due to the reason described above. Very useful in

Step (4) is preferably a step of developing the exposed resist film with a developing solution to form a resist pattern. The developing solution may be an alkali developing solution or a developing solution containing an organic solvent. There may be.
As the alkali developer, a quaternary ammonium salt represented by tetramethylammonium hydroxide is usually used, but an alkaline aqueous solution such as an inorganic alkali, a tertiary amine, an alcoholamine, or a cyclic amine is also used. It is possible.
Specifically, examples of the alkali developing solution include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; and primary alkalis such as ethylamine and n-propylamine. Amines; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcoholamines such as dimethylethanolamine and triethanolamine; tetramethylammonium hydroxide and tetraethylammonium hydroxy And alkaline amines such as pyrrole and piperidine, and the like. Among these, it is preferable to use an aqueous solution of tetraethylammonium hydroxide.
Further, an appropriate amount of an alcohol or a surfactant may be added to the alkaline developer. The alkali concentration of the alkali developer is usually from 0.1 to 20% by mass. The pH of the alkaline developer is usually from 10.0 to 15.0.
The development time using the alkali developer is usually 10 to 300 seconds.
The alkali concentration (and pH) and the development time of the alkali developer can be appropriately adjusted according to the pattern to be formed.
After development using an alkali developing solution, washing may be performed using a rinsing solution. As the rinsing solution, pure water is used, and an appropriate amount of a surfactant may be added.
Further, after the development process or the rinsing process, a process of removing the developing solution or the rinsing solution attached to the pattern by using a supercritical fluid can be performed.
Further, after the rinsing treatment or the treatment with the supercritical fluid, a heat treatment can be performed to remove moisture remaining in the pattern.

As the organic developer, polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents and hydrocarbon solvents can be used. Other than those described in paragraphs [0461] to [0463] of JP-A-048500, there may be mentioned methyl 2-hydroxyisobutyrate, butyl butyrate, isobutyl isobutyrate, butyl propionate, butyl butanoate and isoamyl acetate.
A plurality of the above solvents may be mixed, or a mixture of a solvent other than the above and water may be used. However, in order to sufficiently exhibit the effects of the present invention, the water content of the entire developer is preferably less than 10% by mass, and more preferably substantially no water content.
That is, the amount of the organic solvent used in the organic developer is preferably 90% by mass or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less based on the total amount of the developer.

  In particular, the organic developer is preferably a developer containing at least one organic solvent selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. .

  The vapor pressure of the organic developer at 20 ° C. is preferably 5 kPa or less, more preferably 3 kPa or less, and particularly preferably 2 kPa or less. By reducing the vapor pressure of the organic developer to 5 kPa or less, the evaporation of the developer on the substrate or in the developing cup is suppressed, the temperature uniformity on the wafer surface is improved, and as a result, the dimensional uniformity on the wafer surface is improved. The property improves.

An appropriate amount of a surfactant can be added to the organic developer as needed.
Although the surfactant is not particularly limited, for example, an ionic or nonionic fluorine-based and / or silicon-based surfactant can be used. As these fluorine and / or silicon surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, U.S. Pat. No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,436,098, No. 5,576,143, No. 5,294,511, and No. 5,824,451. , Preferably a nonionic surfactant. The nonionic surfactant is not particularly limited, but it is more preferable to use a fluorine-based surfactant or a silicon-based surfactant.

  The amount of the surfactant to be used is generally 0.001 to 5% by mass, preferably 0.005 to 2% by mass, more preferably 0.01 to 0.5% by mass, based on the total amount of the developer.

  The organic developer may contain a basic compound. Specific examples and preferred examples of the basic compound that can be contained in the organic developer used in the present invention are the same as those of the basic compound that can be contained in the composition described above as the acid diffusion controller.

  As a developing method, for example, a method of dipping a substrate in a bath filled with a developing solution for a certain period of time (dip method), a method of raising the developing solution on the substrate surface by surface tension and stopping for a certain period of time (paddle) Method), a method of spraying a developing solution onto a substrate surface (spray method), and a method of continuously discharging a developing solution while scanning a developing solution discharge nozzle at a constant speed on a substrate rotating at a constant speed (dynamic dispense method). Etc. can be applied. The suitable range of the discharge pressure of the discharged developer and the method of adjusting the discharge pressure of the developer are not particularly limited, but, for example, paragraphs [0631] to [0631] of JP-A-2013-2422397. 0636] can be used.

In the pattern forming method of the present invention, a step of developing using an alkali developing solution (alkali developing step) and a step of developing using a developing solution containing an organic solvent may be used in combination. Thereby, a finer pattern can be formed.
In the present invention, portions having low exposure intensity are removed by the organic solvent development process, and portions having high exposure intensity are also removed by further performing the alkali development process. By the multiple development process in which development is performed a plurality of times in this manner, a pattern can be formed without dissolving only a region having an intermediate exposure intensity, so that a finer pattern than usual can be formed (see paragraphs of JP-A-2008-292975). Mechanism similar to [0077]).
In the pattern forming method of the present invention, the order of the alkali developing step and the organic solvent developing step is not particularly limited, but it is more preferable to perform the alkali developing before the organic solvent developing step.

After the step of developing with a developer containing an organic solvent, it is preferable to include a step of washing with a rinse solution.
The rinsing liquid used in the rinsing step after the step of developing with a developing solution containing an organic solvent is not particularly limited as long as the resist pattern is not dissolved, and a solution containing a general organic solvent can be used. . As the rinsing liquid, use a rinsing liquid containing at least one organic solvent selected from the group consisting of hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. Is preferred.
Specific examples of the hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, alcohol-based solvent, amide-based solvent, and ether-based solvent include the same ones as described in the developer containing an organic solvent.

After the step of developing using a developer containing an organic solvent, more preferably, at least one kind selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, amide solvents, and hydrocarbon solvents. Performing a step of cleaning using a rinse liquid containing an organic solvent, more preferably performing a step of cleaning using a rinse liquid containing an alcohol-based solvent or an ester-based solvent, particularly preferably containing a monohydric alcohol The cleaning step is performed using a rinsing liquid, and most preferably, the cleaning step is performed using a rinsing liquid containing a monohydric alcohol having 5 or more carbon atoms.
As the rinsing liquid containing a hydrocarbon solvent, a hydrocarbon compound having 6 to 30 carbon atoms is preferable, a hydrocarbon compound having 8 to 30 carbon atoms is more preferable, and a hydrocarbon compound having 10 to 30 carbon atoms is particularly preferable. Above all, by using a rinsing liquid containing decane and / or undecane, pattern collapse is suppressed.
When an ester solvent is used as the organic solvent, a glycol ether solvent may be used in addition to the ester solvent (one or two or more). As a specific example in this case, use of an ester-based solvent (preferably, butyl acetate) as a main component and a glycol ether-based solvent (preferably, propylene glycol monomethyl ether (PGME)) as a sub-component is exemplified. Thereby, residue defects are further suppressed.

  Here, examples of the monohydric alcohol used in the rinsing step include linear, branched, and cyclic monohydric alcohols, and specifically, 1-butanol, 2-butanol, and 3-methyl-1-butanol. Tert-butyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 4-methyl-2-pentanol, 1-heptanol, 1-octanol, 2-hexanol, cyclopentanol, 2-heptanol, 2 -Octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol and the like can be used. Particularly preferred monohydric alcohols having 5 or more carbon atoms include 1-hexanol, 2-hexanol and 4-methyl-. Using 2-pentanol, 1-pentanol, 3-methyl-1-butanol, etc. It can be.

A plurality of each component may be mixed, or a mixture with an organic solvent other than the above may be used.
The water content in the rinsing liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. By setting the water content to 10% by mass or less, good development characteristics can be obtained.

  The vapor pressure of the rinsing liquid used after the step of developing using a developing solution containing an organic solvent is preferably from 0.05 kPa to 5 kPa at 20 ° C., more preferably from 0.1 kPa to 5 kPa, more preferably from 0.1 kPa to 5 kPa. The pressure is most preferably 12 kPa or more and 3 kPa or less. By setting the vapor pressure of the rinsing liquid to 0.05 kPa or more and 5 kPa or less, the temperature uniformity in the wafer surface is improved, and the swelling due to the penetration of the rinsing liquid is suppressed, and the dimensional uniformity in the wafer surface is reduced. Is improved.

An appropriate amount of a surfactant may be added to the rinse solution.
In the rinsing step, the wafer that has been developed using the developing solution containing an organic solvent is subjected to a cleaning process using the above-mentioned rinsing solution containing the organic solvent. The method of the cleaning treatment is not particularly limited. For example, a method of continuously discharging the rinsing liquid onto the substrate rotating at a constant speed (rotation coating method), or immersing the substrate in a bath filled with the rinsing liquid for a predetermined time A method (dip method), a method of spraying a rinsing liquid on a substrate surface (spray method), and the like can be applied. Among them, a cleaning process is performed by a spin coating method, and after cleaning, the substrate is rotated at a rotation speed of 2000 rpm to 4000 rpm. It is preferable that the rinsing liquid is rotated to remove the rinsing liquid from the substrate. It is also preferable to include a heating step (Post Bake) after the rinsing step. The developer and the rinsing liquid remaining between the patterns and inside the patterns are removed by the baking. The heating step after the rinsing step is usually performed at 40 to 160 ° C, preferably 70 to 95 ° C, usually for 10 seconds to 3 minutes, preferably for 30 seconds to 90 seconds.

It is preferable that the resist composition of the present invention and various materials (for example, a developer and a rinsing liquid) used in the pattern forming method of the present invention do not contain impurities such as metals. Examples of the metal impurity component include Na, K, Ca, Fe, Cu, Mn, Mg, Al, Cr, Ni, Zn, Ag, Sn, Pb, and Li. The total content of impurities contained in these materials is preferably 1 ppm (parts per million) or less, more preferably 10 ppb or less, further preferably 100 ppt (parts per trillion) or less, particularly preferably 10 ppt or less, and most preferably 1 ppt or less. preferable.
Examples of a method for removing impurities such as metals from the above various materials include filtration using a filter. The pore size of the filter is preferably 50 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. As a material of the filter, a filter made of polytetrafluoroethylene, polyethylene, or nylon is preferable. In the filter filtration step, a plurality of types of filters may be connected in series or in parallel. When a plurality of types of filters are used, filters having different pore sizes and / or materials may be used in combination. Further, various materials may be filtered a plurality of times, and the step of filtering a plurality of times may be a circulation filtration step.
Further, as a method of reducing impurities such as metals contained in the various materials, select a material having a low metal content as a material constituting the various materials, perform a filter filtration on the materials constituting the various materials, And the like. Preferred conditions for filter filtration performed on raw materials constituting various materials are the same as those described above.
In addition to filter filtration, removal of impurities by an adsorbent may be performed, or filter filtration and an adsorbent may be used in combination. As the adsorbent, a known adsorbent can be used. For example, an inorganic adsorbent such as silica gel and zeolite, and an organic adsorbent such as activated carbon can be used.
In order to reduce impurities such as metals contained in the various materials, it is necessary to prevent metal impurities from being mixed in the manufacturing process. Whether or not metal impurities have been sufficiently removed from the manufacturing apparatus can be confirmed by measuring the content of the metal component contained in the cleaning liquid used for cleaning the manufacturing apparatus. The content of the metal component contained in the used cleaning solution is preferably 100 ppt (parts per trillion) or less, more preferably 10 ppt or less, and particularly preferably 1 ppt or less.
The resist composition of the present invention, and the organic processing solution used in the pattern forming method of the present invention (resist solvent, developing solution, rinsing solution, etc.) are charged with static electricity, a chemical solution pipe and various kinds of liquid accompanying the subsequent electrostatic discharge. In order to prevent failure of parts (filters, O-rings, tubes, etc.), a conductive compound may be added. The conductive compound is not particularly limited, but includes, for example, methanol. The addition amount is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, from the viewpoint of maintaining preferable development characteristics. Regarding the member of the chemical solution piping, various types of piping coated with SUS (stainless steel) or polyethylene, polypropylene or fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, etc.) subjected to antistatic treatment may be used. it can. Similarly, for the filter and the O-ring, polyethylene, polypropylene, or a fluororesin (polytetrafluoroethylene, perfluoroalkoxy resin, or the like) subjected to an antistatic treatment can be used.

A method for improving the surface roughness of the pattern may be applied to the pattern formed by the method of the present invention. As a method of improving the surface roughness of the pattern, for example, there is a method of treating a resist pattern with a plasma of a gas containing hydrogen disclosed in WO2014 / 002808A1. In addition, JP-A-2004-235468, US2010 / 0020297A, JP-A-2008-83384, Proc. of SPIE Vol. 8328 83280N-1 "A known method as described in" EUV Resist Curing Technology for LWR Reduction and Etch Selection Enhancement "may be applied.
The pattern forming method of the present invention can also be used for guide pattern formation in DSA (Directed Self-Assembly) (for example, see ACS Nano Vol. 4 No. 8 Page 4815-4823).
The resist pattern formed by the above method can be used, for example, as a core material in a spacer process disclosed in JP-A-3-270227 and JP-A-2013-164509.

  Further, a pattern miniaturization process may be applied to the pattern formed by the method of the present invention. As a pattern miniaturization process, for example, as described in JP-A-2013-145290 and JP-A-2014-071424, a composition for miniaturization is applied on a pattern and heated to form a resist pattern. There is a method of increasing the width. Note that the composition for miniaturization preferably contains silicon atoms in order to maintain the etching resistance of the resist pattern after the miniaturization process.

[Step (5): Pattern forming step]
Step (5) is a step of forming a pattern by processing the resist underlayer film using the resist pattern formed in step (4) as a mask.

The method of processing the resist underlayer film is not particularly limited, but step (5) is preferably a step of forming a pattern by performing dry etching on the resist underlayer film using the resist pattern as a mask.
The dry etching may be a single-stage etching or a multi-stage etching. When the etching is etching having a plurality of stages, the etching in each stage may be the same process or different processes.
Although the type of the dry etching apparatus is not particularly limited, in particular, an ICP (Inductive Coupled Plasma, inductive coupling) type, a dual-frequency CCP (Conductive Coupled Plasma capacitive coupling) type, an ECR (electron cyclotron resonance); It is more preferable to use such a method as to independently control the plasma density and the bias voltage.
For the etching, any known method can be used, and various conditions and the like are appropriately determined according to the type and use of the substrate. For example, Proceedings of the International Society of Optical Engineering (Proc. Of SPIE) Vol. Etching can be performed according to 6924, 692420 (2008), JP-A-2009-267112, and the like. In addition, the method described in “Chapter 4 Etching” of “Semiconductor Process Textbook 4th Edition, published in 2007, Publisher: SEMI Japan” can be used.

In particular, the dry etching for the resist underlayer film is preferably oxygen plasma etching.
The term “oxygen plasma etching” as used herein means plasma etching using a gas containing oxygen atoms, and specifically, O ₂ , O ₃ , CO, CO ₂ , NO, NO ₂ , N ₂ O , SO, SO ₂ , COS, and the like. Further, in addition to the oxygen-containing gas, at least one selected from the group consisting of Ar, He, Xe, Kr, and N _{2 is used} as a diluent gas, and Cl ₂ , HBr, BCl ₃ , CH ₄ , and NH _{4 are used} as additional gases. At least one member may be added from the group consisting of:
When an oxygen atom-containing gas is used, the irradiation effect of oxygen radicals and oxygen ions generated in the plasma promotes the etching of the resist underlayer film. On the other hand, with respect to the silicon-containing resist film, oxidation and oxidation of silicon components in the resist film are performed. Agglomeration enhances the etching resistance, and can increase the selectivity between the silicon-containing resist film and the resist underlayer film.
In the case of suppressing a pattern dimension variation before and after etching, an oxygen-containing gas containing oxygen atoms and at least one of C, N, S (eg, CO, CO ₂ , NO, NO ₂ , N ₂ O, SO, SO ₂ , By increasing the ratio of (COS), the deposition component generated in the plasma adheres to the sidewall of the etching pattern, suppressing the side etching effect due to oxygen radicals, and reducing the line width before and after etching. Become. The above effect can also be obtained by adding CH ₄ or NH ₄ as an additive gas to an oxygen-containing gas (for example, O ₂ , O ₃ , CO, CO ₂ , NO, NO ₂ , N ₂ O, SO, SO ₂ , COS). Be demonstrated.
When a gas containing a halogen element other than fluorine, such as Cl ₂ or HBr, is used, a high-boiling carbon chloride or a carbon bromide is formed as an etching product of the underlayer film, and the adhesion to the processing pattern side wall is enhanced. Also in this case, an effect of suppressing side etching by oxygen radicals can be expected.
On the other hand, by appropriately selecting the mixing ratio of the O ₂ or O ₃ gas and the diluent gas, the side etching amount of the silicon-containing resist film and the resist underlayer film is controlled, and the trimming process of a desired size is performed simultaneously with the etching. Is also possible.

In semiconductor device manufacturing, a pattern is formed by applying a resist underlayer film or a resist film to a substrate to be processed, and then performing exposure, development processing, and the like. There is a step of checking whether or not is actually formed. If the dimension is out of the allowable range, a method of removing and removing the underlayer film and the resist layer and re-performing the pattern formation from the application of the resist underlayer film and the resist film is generally performed (rework step).
In this case, it is important to completely remove and remove the resist underlayer film and the resist film on the substrate to be processed in order to prevent defects from occurring in the exposure and development processes. In a normal resist film stripping method, most of the organic compounds on the substrate are removed by dry processing (ashing) using oxygen gas, and a rinsing treatment is performed as necessary to remove the resist film almost completely. It is possible and widely practiced.
However, in a two-layer resist system using a silicon-containing resist film as in the present invention, when the above-described ashing treatment is performed, the silicon-containing resist film remains in the form of silicon oxide, making it difficult to completely remove it. There is fear.
For this reason, when performing rework by dry processing, it is necessary to select an etching gas so that the etching rate of the silicon-containing resist film does not become too slow. For example, a fluorine-based gas such as CF ₄ is applicable for this purpose.
In the case of the above-mentioned dry treatment, there is a possibility that the types of the resist underlayer film and the substrate to be used may be limited. Therefore, a wet treatment is preferable as a method for reworking the silicon-containing resist film. Examples of the treatment liquid (stripping liquid) applied in this case include a mixed liquid of sulfuric acid and hydrogen peroxide, a diluted fluorine aqueous solution, an alkaline aqueous solution, an organic solvent, and the like, but are not limited thereto.
In the above wet treatment, it is more preferable to add a surfactant to the treatment liquid in order to effectively perform wet peeling. Examples of the surfactant include a fluorine-based surfactant and a silicon-based surfactant.
Prior to the wet stripping step, processes such as overall exposure and heating can be applied to the silicon wafer on which the resist film has been formed. By promoting the polarity conversion reaction of the resist film, an effect of improving solubility in a wet processing solution can be expected.

The present invention also relates to an ion implantation method in which ions are implanted into a substrate to be processed using a pattern obtained by the pattern forming method of the present invention as a mask.
As a method of ion implantation, any known method can be adopted.

  The present invention provides a resist underlayer film, a resin having an atom selected from the group consisting of Si atoms and Ti atoms, and a resin (B) which is used in the pattern forming method of the present invention. The present invention also relates to a laminate in which a resist film formed from a resist composition containing a compound that generates an acid upon irradiation with actinic rays or radiation is laminated in this order. The details of the substrate to be processed, the resist underlayer film, the resist film, and the like in the laminate of the present invention are the same as those described in the pattern forming method of the present invention.

  The present invention also relates to a kit including a resist underlayer film forming composition for forming a resist underlayer film and a resist composition, which is used in the above-described pattern forming method of the present invention.

The present invention also relates to the composition for forming a resist underlayer film included in the kit.
The present invention also relates to a resist composition contained in the above kit.
The present invention also relates to a composition for forming a resist underlayer film used in the pattern forming method of the present invention.
The present invention also relates to a resist composition used in the pattern forming method of the present invention.

The present invention also relates to a method for manufacturing an electronic device, including the above-described pattern forming method or ion implantation method of the present invention, and an electronic device manufactured by this manufacturing method.
The electronic device of the present invention is suitably mounted on electric / electronic equipment (home appliances, office automation (OA) / media-related equipment, optical equipment, communication equipment, and the like).

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

<Synthesis Example 1: Synthesis of resin PRP-1>
70.91 g of cyclohexanone was placed in a three-necked flask under a nitrogen stream, and heated to 80 ° C. Then, 17.0 g, 10.60 g, 8.17 g, and a polymerization initiator V-601 (0.553 g, manufactured by Wako Pure Chemical Industries, Ltd.) were sequentially added to the monomer corresponding to each repeating unit of the resin PRP-1 described below from the left. A solution dissolved in 105 g of cyclohexanone was added dropwise over 6 hours. After the completion of the dropwise addition, the reaction was further performed at 80 ° C. for 2 hours. After allowing the reaction solution to cool, it was dropped into a mixture of methanol and water over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain the following resin PRP-1 (31.6 g), which is an acid-decomposable resin. Was. The composition ratio (molar ratio) of the repeating unit determined by NMR (nuclear magnetic resonance) was 15/45/40. The weight average molecular weight (Mw) of the obtained resin PRP-1 was 12000 in terms of standard polystyrene determined by GPC, and the degree of dispersion (Mw / Mn) was 1.5.

  Other polymers were synthesized by a similar procedure or a known procedure.

  The structures of the resins PRP-1 to PRP-6 are shown below. The composition ratio (molar ratio), weight average molecular weight (Mw), and degree of dispersion (Mw / Mn) of each resin are shown below.

<Preparation of resin composition>
After mixing the ingredients with the compositions shown in Tables 1 and 2, respectively, the mixture was filtered through a polyethylene filter having a pore size of 0.03 μm to prepare a composition for forming a resist underlayer film and a resist composition. Table 2 below shows the Si content (% by mass) based on the total amount of the resin before and after acid decomposition.

  Abbreviations in the above table are as follows. In addition, the composition ratio of each repeating unit of the resin was represented by a molar ratio.

<Resin for resist underlayer film>

<Crosslinking agent>

<Thermal acid generator>

<Resin for resist composition>
The resin for the resist composition is as described above.

<Photoacid generator>

<Acid diffusion controller>

<Surfactant>

<Solvent>
S-1: Propylene glycol monomethyl ether acetate (PGMEA)
S-2: Propylene glycol monomethyl ether (PGME)
S-3: Ethyl lactate S-4: Ethyl 3-ethoxypropionate

[Examples of KrF exposure] (Examples 1 to 6, Comparative Examples 1 and 2)
A silicon wafer is subjected to HMDS (hexamethyldisilazane) treatment (110 ° C. for 35 seconds), and a resist underlayer film and a resist film are formed thereon in this order under the conditions shown in Table 3 to form a wafer having a laminate. did. In addition, when the layer was not described in the table, the next layer was formed without forming the general layer.
The obtained wafer was subjected to pattern exposure using a KrF excimer laser scanner (PAS5500 / 850, manufactured by ASML) (NA 0.80). A reticle used was a line and space pattern binary mask having a line width of 200 nm and a space width of 200 nm. Then, after baking (Post Exposure Bake; PEB) under the conditions shown in the following Table 3, it was developed by paddle development with a developing solution shown in the following Table 3 for 30 seconds. After rinsing by paddle rinsing with a rinse solution, the wafer was rotated at a rotation speed of 4000 rpm for 30 seconds to obtain a line and space pattern having a pitch of 400 nm, a line width of 200 nm, and a space width of 200 nm. The results are summarized in Table 3.

  Abbreviations in the above table are as follows.

<Rinse liquid>
D-1: pure water D-2: 4-methyl-2-pentanol D-3: n-undecane

  Next, in Examples 1 to 6 and Comparative Example 2, with respect to the silicon wafer on which the resist pattern was formed, the resist underlayer film was etched under the following etching conditions using a parallel plate type reactive ion etching apparatus DES-245R manufactured by Plasma System. did.

(Etching conditions)
Etching gas: O ₂
Pressure: 20mTorr
Applied power: 800 mW / cm ²
Bias power: 300W

  The evaluations in the above table were performed based on the following evaluation methods.

[Pattern collapse]
A pattern described on a silicon wafer as a substrate to be processed (a laminated body of a resist underlayer film pattern and a resist pattern in Examples 1 to 6 and Comparative Example 2, a resist pattern in Comparative Example 1) is used for length-measuring scanning electron Observation was performed using a microscope (S-9380II, manufactured by Hitachi, Ltd.), and pattern collapse was evaluated based on the following criteria.

A: The pattern collapse area in the wafer area is A: less than 5% B: 5% to less than 10% C: 10% to less than 20% D: 20% or more

As is clear from Table 3, in comparison with Comparative Example 1 in which the resist underlayer film was not provided and Comparative Example 2 in which the thickness of the resist layer was large, according to Examples 1 to 6, the thick film (2. (5 μm or more), and a pattern excellent in pattern collapse performance was formed.
Therefore, the present invention is very useful when implanting ions into a substrate in which a specific region is masked by a resist pattern having a large thickness, for example, when implanting ions into a deep portion of a substrate. .

  According to the present invention, a pattern forming method capable of forming a pattern having a large thickness (for example, 2.5 μm or more) and hardly causing pattern collapse, an ion implantation method using the same, and the pattern forming method The present invention can provide a laminate, a kit, a composition for forming a resist underlayer film, a resist composition, and a method for producing an electronic device used in the method.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on August 30, 2017 (Japanese Patent Application No. 2017-165909), the contents of which are incorporated herein by reference.

Claims (19)

(1) forming a resist underlayer film on a substrate to be processed;
(2) forming a resist film on the resist underlayer film using a resist composition containing (A) a resin having an atom selected from the group consisting of Si atoms and Ti atoms;
(3) exposing the resist film;
(4) developing the exposed resist film to form a resist pattern;
(5) forming a pattern by processing the resist underlayer film using the resist pattern as a mask,
A pattern forming method, wherein the thickness of the resist underlayer film is 2.5 μm or more, and the thickness of the resist film is 1 μm or less.   The pattern forming method according to claim 1, wherein the resin (A) is a resin having a Si atom.   3. The pattern forming method according to claim 2, wherein the content of Si atoms in the resin (A) is 1 to 30% by mass based on the total amount of the resin (A).   The pattern forming method according to any one of claims 1 to 3, wherein the resin (A) has a repeating unit having an acid-decomposable group.   The pattern forming method according to any one of claims 1 to 4, wherein the resin (A) has at least one selected from the group consisting of a lactone structure, a sultone structure, and a carbonate structure.   The step (4) is a step of developing the exposed resist film with a developer to form a resist pattern, and the developer is an alkali developer. 4. The pattern forming method according to 1.   The pattern forming method according to claim 1, wherein in the step (3), the resist film is exposed by any one of KrF exposure, ArF exposure, and ArF immersion exposure.   The pattern formation according to any one of claims 1 to 7, wherein the step (5) is a step of forming a pattern by performing dry etching on the resist underlayer film using the resist pattern as a mask. Method.   The pattern forming method according to claim 8, wherein the dry etching for the resist underlayer film is oxygen plasma etching.   The pattern forming method according to claim 1, wherein the resist underlayer film has a thickness of 4 μm or more.   The pattern forming method according to claim 1, wherein the resist composition is a chemically amplified resist composition.   An ion implantation method, wherein the pattern obtained by the pattern formation method according to any one of claims 1 to 11 is used as a mask to implant ions into the substrate to be processed.   A resin having a resist underlayer film and an atom selected from the group consisting of (A) Si atoms and Ti atoms on a substrate to be used, which is used in the pattern forming method according to claim 1. And (B) a laminate in which a resist film formed of a resist composition containing a compound that generates an acid upon irradiation with actinic rays or radiation is laminated in this order.   A kit comprising the composition for forming a resist underlayer film for forming the resist underlayer film used in the pattern forming method according to claim 1, and the resist composition.   A composition for forming a resist underlayer film included in the kit according to claim 14.   A resist composition contained in the kit according to claim 14.   A resist underlayer film forming composition used in the pattern forming method according to claim 1.   A resist composition used in the pattern forming method according to claim 1.   A method for manufacturing an electronic device, comprising: the pattern forming method according to any one of claims 1 to 11 or the ion implantation method according to claim 12.