TW201405249A - Method for forming negative resist pattern and photoresist composition - Google Patents

Abstract

The present invention is a method for forming a negative resist pattern, which comprises: a step for forming a resist film using a photoresist composition; a step for exposing the resist film; and a step for developing the exposed resist film using a developer liquid that contains an organic solvent. The photoresist composition contains: (A) a polymer that has a structural unit (I) represented by formula (1) and at least one structural unit (II) selected from the group consisting of structural units represented by formula (2-1), formula (2-2) and formula (2-3); and (B) an acid generator. The total of the content ratios of the structural unit (I) and the structural unit (II) in the polymer (A) is 90% by mole or more.

Description

Negative resist pattern formation method and photoresist composition

The present invention relates to a negative photoresist pattern forming method and a photoresist composition.

The chemically amplified photoresist composition uses an ultraviolet light or an electron beam such as ArF excimer laser light or KrF excimer laser light to generate an acid in an exposed portion, and reacts the acid as a catalyst to thereby expose the film. The portion and the unexposed portion differ in the dissolution rate of the developing solution, and a composition of the photoresist pattern is formed on the substrate.

In the formation of a photoresist pattern using the photoresist composition, an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) has been used as the above-mentioned developing solution to form a positive type of resistive pattern. image. However, in recent years, as a technique of using an existing apparatus without increasing the resolution under the step, an organic solvent having a lower polarity than an aqueous alkali solution is used as a developing liquid to form a negative-type development image of a negative resist pattern ( Refer to JP-A-2000-199953).

As a photoresist composition in the negative development, as in the case of positive development, a structural unit having an acid-dissociable group and a A polymer of a structural unit of a lactone structure or a sultone structure (hereinafter also referred to as "lactone structure"). The lactone structure or the like can impart hydrophilicity to the polymer, adjust the solubility to a developing solution such as an aqueous alkali solution, and improve the adhesion of the formed resist film to the substrate. The situation of type imaging is considered to be the most appropriate.

However, in the negative development, since the polarity of the developing liquid used and the like are different from those in the positive development, it is considered that the polarity of the most suitable polymer is completely different. Therefore, from the viewpoint of improving the lithography performance such as the sensitivity, the resolution, and the LWR (Line With Roughness) performance of the photoresist composition, the lactone structure and the like cannot be said to be most suitable, and it is considered that Even if the lactone structure or the like is not substantially used in the polymer, the lithographic properties of the photoresist composition can be further improved. Further, since a monomer having a lactone structure or the like is generally complicated and expensive to be synthesized, it is possible to reduce the cost of the photoresist composition without using such a monomer.

According to this, in the formation of a negative pattern using a developing solution containing an organic solvent, it is desirable to form a resin having excellent LWR performance, resolution, and cross-sectional shape without using a lactone structure or the like. The method of lithographic performance of the photoresist pattern.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] JP-A-2000-199953

The present invention has been made in view of the above circumstances, and an object thereof is to provide a negative resistivity pattern which can form an LWR property, an image resolving property, and a cross-sectional shape without using a lactone structure or a sultone structure. Type of photoresist pattern formation method.

The invention for solving the above problems is a negative resist pattern forming method having the steps of: forming a resist film using a photoresist composition; exposing the resist film; and using organic a solvent developing solution for developing the exposed resist film, wherein the photoresist composition contains a structural unit (I) represented by the following formula (1) and is represented by the following formula (2-1) a polymer of at least one structural unit (II) selected from the group consisting of structural units represented by formula (2-2) and formula (2-3) (hereinafter also referred to as "[A] polymer"), and acid a product (hereinafter also referred to as "[B] acid generator"), wherein the total content of the structural unit (I) and the structural unit (II) in the polymer is 90 mol% or more. (In the formula (I), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ² is a monovalent acid dissociable group), (In the formula (2-1), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁴ is a single bond, *-C(=O)-O- or *-C(=O) -NH-, however, * represents a bonding site with a carbon atom to which R ³ is bonded, and R ⁵ is a single bond, a methylene group or an alkylene group having a carbon number of 2 to 5, and R ⁶ is a ring member number 5~ a monovalent aliphatic heterocyclic group of 20, a monovalent chain hydrocarbon group having 1 to 5 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a hydrogen atom, and the above aliphatic heterocyclic group is contained between carbon and carbon Contains -OC(=O)-O-, -SC(=S)-O-, -C(=O)-N(-* *)-C(=O)-, -O-, and -S- At least one selected from the group consisting of one or more hydrogen atoms of the chain hydrocarbon group and the alicyclic hydrocarbon group selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, an -NHSO ₂ R ^a group and an oxo group At least one base is substituted, R ^a is an alkyl group having 1 to 5 carbon atoms which may be substituted by a fluorine atom, * * represents a bonding site with R ⁵ , and in the formula (2-2), R ⁷ and R ^{8 are} each independently R ⁹ to R ^{12 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but two or more of R ⁹ to R ¹² may be bonded to each other to form a hydrogen atom, a fluorine atom or a methyl group. The carbon number of the carbon atom to be bonded is 3 to 10 ring structure, m1 and m2 Independently being an integer of 0~2, when R ⁹ ~ R ^{12 are} each plural, a plurality of R ⁹ ~ R ¹² may be the same or different, R ¹³ is -O- or -NR ^A -, and R ^A is a hydrogen atom. a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a hydrogen atom of a part of the alkyl group, a cycloalkyl group and an aryl group via a hydroxyl group or a carboxyl group In the formula (2-3), R ¹⁴ is a hydrogen atom or a methyl group, and R ¹⁵ to R ^{18 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but in R ¹⁵ to R ¹⁸ Two or more layers may be bonded to each other to form a ring structure including carbon atoms of the bonded carbon atoms of 3 to 10, and n1 and n2 are each independently an integer of 0 to 2, and when R ¹⁵ to R ¹⁸ are plural , a plurality of R ¹⁵ to R ¹⁸ may be the same or different, R ¹⁹ is -O- or -NR ^B -, and R ^B is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, and a carbon number of 4 to 20 a cycloalkyl group, an aryl group having 6 to 20 carbon atoms, or a group in which a part of hydrogen atoms of the alkyl group, the cycloalkyl group and the aryl group are substituted by a hydroxyl group or a carboxyl group).

The photoresist composition of the present invention is a negative-type pattern-forming photoresist composition using a developing solution containing an organic solvent, and is characterized in that it has a structural unit (I) represented by the above formula (1) and a polymer of at least one structural unit (II) selected from the group consisting of structural units represented by formula (2-1), formula (2-2), and formula (2-3), and In the acid generator, the total content ratio of the structural unit (I) and the structural unit (II) in the above polymer is 90 mol% or more.

According to the negative resist pattern forming method and the photoresist composition of the present invention, in the pattern formation using a developing solution containing an organic solvent, a monomer having a lactone structure or a sultone structure can be used without forming a monomer. A negative resist pattern with a small LWR, high resolution, and excellent squareness in cross-sectional shape. Accordingly, these can be suitably applied to pattern formation in the field of semiconductor fabrication which is more refined.

<Formation method of negative resist pattern>

The negative resist pattern formation method is a step of forming a resist film on a substrate by using a photoresist composition (hereinafter also referred to as "photoresist composition (I)") (hereinafter also referred to as "resist film" Forming step")

a step of exposing the resist film (hereinafter also referred to as "exposure step"), and a step of developing the exposed resist film using a developing solution containing an organic solvent (hereinafter also referred to as "development step" ").

According to the negative photoresist pattern forming method, due to the use of light Since the composition (I) is formed, a resist pattern having a small LWR, a high resolution, and a rectangular shape in a cross-sectional shape can be formed. Hereinafter, each step will be described. The photoresist composition (I) is described later.

[Resistance film forming step]

In this step, the photoresist composition (I) is applied onto a substrate to form a resist film. As the substrate, a conventionally known substrate such as a germanium wafer or an aluminum-coated wafer can be used. In addition, an organic or inorganic antireflection film disclosed in, for example, JP-A-6-12452 or JP-A-59-93448 can be formed on the substrate.

The coating method is exemplified by spin coating, casting coating, roll coating, and the like. Further, the film thickness of the formed photoresist film is usually from 0.01 μm to 1 μm, preferably from 0.01 μm to 0.5 μm.

After the photoresist composition (I) is applied, the solvent in the coating film may be volatilized by prebaking (PB) as needed. The temperature condition of PB is appropriately selected depending on the composition of the photoresist composition (I), but it is usually about 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C.

In order to prevent the influence of the alkaline impurities and the like contained in the environmental atmosphere, a protective film disclosed in, for example, JP-A-5-188598 can be provided on the resist film. In addition, in order to prevent the outflow of the self-resistance film such as an acid generator, a protective film for liquid immersion disclosed in, for example, JP-A-2005-352384 can be provided on the resist film. Also, these techniques can be used in combination.

[Exposure step]

This step exposes the resist film formed in the resist film formation step. The exposure is performed by reducing the projection or the like through a mask of a specific pattern and an optional liquid immersion liquid to the desired area. For example, a contour pattern can be formed by reducing the projection exposure or the like of a desired region through a contour pattern mask. Further, the exposure can be performed twice or more using the desired pattern and mask pattern. When two or more exposures are performed, it is preferred to continuously perform exposure. In the case of a plurality of exposures, for example, the first reduction projection exposure or the like is performed through the line and the interval mask in a desired region, and then the exposure portion for performing the first exposure is subjected to the second pass so that the lines intersect. Reduce the projection exposure and so on. The first exposure unit and the second exposure unit are preferably orthogonal to each other. By orthogonality, a true circular contact hole pattern can be easily formed in the unexposed portion surrounded by the exposure portion. Further, the liquid immersion liquid used for the exposure is exemplified by water or a fluorine-based inert liquid. The liquid immersion liquid is transparent to the exposure wavelength, and in order to keep the deformation of the optical image projected on the film to a minimum, it is preferable that the temperature coefficient of the refractive index is as small as possible, but especially the exposure light source is ArF excimer. In the case of laser light (wavelength: 193 nm), in addition to the above viewpoints, water is preferably used in terms of ease of handling and ease of handling. When water is used, a small proportion of additives which reduce the surface tension of water while increasing the interfacial activity can also be added. Preferably, the additive does not dissolve the resist layer on the wafer and is negligible for the optical coating beneath the lens. The water used is preferably distilled water.

The electromagnetic wave or charged particle beam used in the exposure is appropriately selected depending on the type of the [B] acid generator. For example, the electromagnetic wave is exemplified by ultraviolet light, far ultraviolet light, visible light, X-ray, γ-ray, etc., and the charged particle beam is enumerated as an electron beam, α. Rays, etc. Among these, it is preferably far ultraviolet rays and electrons. The beam is preferably far ultraviolet light, and more preferably ArF excimer laser light, KrF excimer laser light (wavelength 248 nm), preferably ArF excimer laser light. The exposure conditions such as the amount of exposure are appropriately selected depending on the composition of the photoresist composition (I), the type of the additive, and the like. In the method for forming a negative resist pattern of the present invention, a plurality of exposure steps may be used, and the same light source may be used for the plurality of exposures, or different light sources may be used, but the ArF excimer laser light is preferably used for the first exposure.

Further, it is preferred to perform post-exposure baking (PEB) after exposure. By carrying out PEB, the dissociation reaction of the acid dissociable group in the photoresist composition (I) proceeds smoothly. The temperature condition of PEB is usually from 30 ° C to 200 ° C, preferably from 50 ° C to 170 ° C.

[development step]

This step is developed after exposure in the exposure step using a negative-type developing solution containing an organic solvent to form a photoresist pattern. The so-called negative imaging solution is selectively dissolved. It is said that the developing liquid of the low-exposure portion and the unexposed portion is removed. The organic solvent contained in the negative-working liquid is preferably at least one selected from the group consisting of an alcohol solvent, an ether solvent, a ketone organic solvent, a guanamine solution, an ester organic solvent, and a hydrocarbon solvent. These organic solvents are exemplified by the same solvents as those exemplified as the solvent (E) contained in the photoresist composition (I) to be described later.

Among these, an ester solvent, a ketone solvent, and an ether solvent are preferable, and an ester solvent and an ether solvent are more preferable, and an ester solvent is more preferable. Specifically, it is anisole, n-butyl acetate, isopropyl acetate, and acetic acid. Amyl ester, methyl ethyl ketone, methyl n-butyl ketone and methyl n-amyl ketone are preferred, more preferably anisole, n-butyl acetate and methyl n-amyl ketone, preferably anisole And n-butyl acetate, preferably n-butyl acetate. These organic solvents may be used singly or in combination of two or more.

In the method for forming a negative resist pattern, the content of the organic solvent in the developing solution is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and most preferably 100% by mass. quality%. When the content of the organic solvent in the developing solution is at least the above lower limit, the contrast of the pattern in which the exposure occurs can be improved, and as a result, a pattern excellent in development characteristics and lithography performance can be formed. Further, the components other than the organic solvent are exemplified by water, eucalyptus oil, and the like.

An appropriate amount of surfactant may be added to the developing solution as needed. The surfactant is exemplified by an ionic or nonionic fluorine-based and/or lanthanoid surfactant.

The development method is, for example, a method in which a substrate is immersed in a bath filled with a developing liquid for a certain period of time (dipping method), and a surface liquid is used to cover the surface of the substrate with a surface tension and is imaged at a standstill for a certain period of time (liquid coating method) a method of spraying a developing solution onto a surface of a substrate (spraying method), and applying a developing solution while scanning a developing solution at a constant speed to scan a developing solution at a constant speed (dynamic coating method) )Wait.

In the method for forming a negative resist pattern, it is preferred to wash the resist film with a washing liquid after development of the developing step. Further, the washing liquid in the washing step may also use an organic solvent to effectively wash the generated dross. The washing liquid is preferably a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, or a guanamine. A solvent or the like. Among these, an alcohol solvent and an ester solvent are preferable, and an alcohol solvent having a carbon number of 6 to 8 is more preferable. The alcohol having 6 to 8 carbon atoms is exemplified by a linear, branched or cyclic monohydric alcohol, and is exemplified by, for example, 1-hexanol, 1-heptanol, 1-octanol, 4-methyl-2- Pentanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, and the like. Among these, 1-hexanol, 2-hexanol, 2-heptanol, and 4-methyl-2-pentanol are preferred.

The components of the above washing liquid may be used singly or in combination of two or more. The water content in the washing liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferably 3% by mass or less. By setting the water content to 10% by mass or less, good development characteristics can be obtained. Further, a surfactant described later may be added to the washing liquid.

The method of the washing treatment is, for example, a method in which a washing liquid is applied onto a substrate that is rotated at a constant speed (a spin coating method), a method in which a substrate is immersed in a tank filled with a washing liquid for a certain period of time (dipping method), and A method of spraying a washing liquid on a substrate surface (spraying method) or the like.

<Photoresist composition (I)>

The photoresist composition (I) is a negative-type pattern-forming photoresist composition using an organic solvent-containing developing solution, which is characterized by containing [A] polymer and {B} acid generator, [A] polymer. The total content ratio of the structural unit (I) and the structural unit (II) in the middle is 90 mol% or more.

The photoresist composition (I) may contain [C] acid diffusion controlling agent, [D] fluorine atom-containing polymer in addition to [A] polymer and [B] acid generator. The [E] solvent is preferably a component and may contain other optional components within the range not impairing the effects of the present invention. The components are described below.

<[A] Polymer>

[A] The polymer is a polymer having a structural unit (I) and a structural unit (II), and the total content ratio of the structural unit (I) and the structural unit (II) is 90 mol% or more. The photoresist composition (I) is formed by using a [A] polymer and forming a negative pattern of a developing liquid containing an organic solvent, and does not use a lactone structure, etc., and has LWR properties and dissolvability. The cross-sectional shape is excellent in squareness.

The photoresist composition (I) has a structural unit (I) having an acid-dissociable group and a structural unit (II) containing the above-mentioned specific polar group in the [A] polymer, by making the total of the content ratios In the above range, a lactone structure or the like can be omitted, and a negative pattern forming method using a developing liquid containing an organic solvent can be used, and the polarity of the polymer can be controlled to be moderate. As a result, in the negative pattern forming method using the developing liquid containing an organic solvent, it is considered that a resist pattern having a small LWR, a high resolution, and excellent cross-sectional rectangularity can be formed.

The [A] polymer may have other structural units in addition to the structural unit (I) and the structural unit (II). The [A] polymer may have one or two or more structural units. The following describes each structural unit.

[structural unit (I)]

The structural unit (I) is a structural unit represented by the following formula (I). [A]aggregation The system has the structural unit (I) and the effect of the acid generated by exposure to the [B] acid generator increases the polarity and reduces the solubility to the developing solution containing the organic solvent. As a result, the photoresist composition (I) makes the exposed portion insoluble or poorly soluble, and the unexposed portion becomes soluble, and a negative resist pattern can be formed.

In the above formula (I), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is a monovalent acid dissociable group. Here, the "acid dissociable group" is a group in which a hydrogen atom of a polar group such as a carboxyl group or a hydroxyl group is substituted, and means a group which is dissociated by the action of an acid.

The above R ¹ is preferably a hydrogen atom or a methyl group from the viewpoint of obtaining the copolymerizability of the monomer of the [A] polymer, and more preferably a methyl group.

The monovalent acid dissociable group represented by the above R ² is not particularly limited, but is preferably a group represented by the following formula (i). The above-mentioned monovalent acid dissociable group is made to have a group represented by the following formula (i) to improve its acid dissociation property. As a result, the LWR performance, the resolution, and the rectangular shape of the cross-sectional shape of the photoresist composition (I) are improved.

In the above formula (i), R ^p1 is a monovalent chain hydrocarbon group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ^p2 and R ^{p3 are} each independently 1 to 4 carbon atoms. A valence chain hydrocarbon group or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or R ^p2 and R ^p3 are bonded to each other to form an alicyclic structure having a ring carbon number of 4 to 20 together with the carbon atoms bonded thereto.

The monovalent chain hydrocarbon group having 1 to 4 carbon atoms represented by the above R ^p1 , R ^p2 and P ^p3 is exemplified by, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and An alkyl group such as a dibutyl group or a tributyl group; an alkenyl group such as an ethynyl group, a propynyl group, a butenyl group or a pentenyl group; an alkynyl group such as an ethynyl group, a propynyl group, a butynyl group or a pentynyl group; and the like.

Among these, an alkyl group is preferred, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably a methyl group or an ethyl group, and most preferably an ethyl group.

The monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by the above R ^p1 , R ^p2 and R ^p3 is exemplified by, for example, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group or a cyclodecyl group. a monocyclic cycloalkyl group such as a cyclodecyl group or a cyclododecyl group; a monocyclic cycloalkenyl group such as a cyclopentenyl group, a cyclohexenyl group or a cyclododecadienyl group; or a monocyclic cycloalkene a polycyclic cycloalkyl group such as norbornyl, adamantyl, tricyclodecyl or tetracyclododecyl; norbornyl, tricyclodecenyl, tetracyclododecadienyl, etc. a cycloalkenyl group or a polycyclic cycloalkadienyl group.

Among these, a cycloalkyl group is preferred, and more preferably a cyclopentyl group, a cyclohexyl group, a norbornyl group or an adamantyl group.

The alicyclic structure of the ring carbon number 4 to 20 in which R ^p2 and R ^p3 are bonded to each other and the carbon atom to be bonded together is, for example, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, or the like. A monocyclic alicyclic structure such as a cycloheptane structure or a cyclooctane structure; a polycyclic alicyclic structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure, or a tetracyclododecane structure.

Among these, a cyclopentane structure, a cyclohexane structure, a norbornane structure, and an adamantane structure are preferable, and a cyclopentane structure and an adamantane structure are more preferable.

The structural unit (I) is, for example, a structural unit represented by the following formulas (1-1) to (1-4) (hereinafter also referred to as "structural unit (I-1) to (I-4)").

In the above formulae (1-1) to (1-4), R ¹ is synonymous with the above formula (1). R ^p1 , R ^p2 and R ^p3 are synonymous with the above formula (i). n _p is an integer from 1 to 4.

The above n _p is preferably 1, 2 or 4, more preferably 1 or 4, and still more preferably 1 from the viewpoint of easiness of dissociation of the acid dissociable group.

The structural unit (I) is exemplified by a structural unit represented by the following formula, and the like.

In the above formula, R ¹ is synonymous with the above formula (1).

The structural unit (I) is preferably a structural unit (I-1) or a structural unit (I-2), more preferably a structural unit derived from 2-alkyl-2-adamantyl (meth)acrylate. The structural unit of 1-alkyl-1-cyclopentyl (meth)acrylate is more preferably derived from 2-ethyl-2-adamantyl (meth)acrylate or (meth)acrylic acid 1 - The structural unit of ethyl-1-cyclopentyl ester.

The lower limit of the content ratio of the structural unit (I) in the polymer [A] is preferably 10 mol%, more preferably 20 mol%, and more preferably the total structural unit constituting the [A] polymer. It is 35 mol%, preferably 45 mol%. On the other hand, the upper limit of the content ratio of the structural unit (I) is preferably 90 mol%, more preferably 80 mol%, still more preferably 65 mol%, and most preferably 55 mol%. When the content ratio of the structural unit (I) is less than the above lower limit, the solubility of the exposed portion to the developing liquid is lowered, the resolution is lowered, and the pattern may be difficult to form. On the other hand, when the content ratio of the structural unit (I) exceeds the above upper limit, the adhesion of the resist pattern formed of the resist composition (I) to the substrate may be lowered.

The monomer which obtained the structural unit (I) is, for example, a compound represented by the following formula (1m).

In the above formula (1m), R ¹ and R ² are synonymous with the above formula (1).

The monomer obtaining the structural unit (I) is preferably a 1-alkyl-1-monocyclic cycloalkyl (meth)acrylate or a 2-alkyl-2-polycyclic cycloalkyl (meth)acrylate. More preferably, it is 1-alkyl-1-cyclopentyl (meth)acrylate, 2-alkyl-2-adamantyl (meth)acrylate, and more preferably 1-ethyl (meth)acrylate. 1-cyclopentyl ester, 2-ethyl-2-adamantyl (meth)acrylate.

[structural unit (II)]

The structural unit (II) is at least one structural unit selected from the group consisting of structural units represented by the above formulas (2-1), (2-2), and (2-3) (hereinafter also referred to as " Structural unit (II-1), "structural unit (II-2)" and "structural unit (II-3)"). Hereinafter, each structural unit will be described.

(structural unit (II-1))

The structural unit (II-1) is a structural unit represented by the following formula (2-1).

In the above formula (2-1), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁴ is a single bond, *-C(=O)-O- or *-C(=O) -NH-, however, * represents a bonding site with a carbon atom to which R ³ is bonded, and R ⁵ is a single bond, a methylene group or an alkylene group having a carbon number of 2 to 5, and R ⁶ is a ring member number 5~ a monovalent aliphatic heterocyclic group of 20, a monovalent chain hydrocarbon group having 1 to 5 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a hydrogen atom, and the above aliphatic heterocyclic group is between carbon and carbon Contains -OC(=O)-O-, -SC(=S)-O-, -C(=O)-N(-* *)-C(=O)-, -O-, and -S- At least one selected from the group consisting of one or more hydrogen atoms of the chain hydrocarbon group and the alicyclic hydrocarbon group is selected from the group consisting of a hydroxyl group, a cyano group, ^a nitro group, a —NHSO ₂ R ^a group and an oxo group. Substituted by at least one group, R ^a is an alkyl group having 1 to 5 carbon atoms which may be substituted by a fluorine atom, * * represents a bonding site with R ⁵ , and as for the above R ³ , a structural unit (II-1) is obtained. From the viewpoint of the copolymerization property of the monomer, a hydrogen atom or a methyl group is preferred, and a methyl group is more preferred.

As for the above R ⁴ , a single bond, *-C(=O)-O- is preferred.

As the above R ⁵ , a single bond, a methylene group, an extended ethyl group, and a 1,2-extended propyl group are preferred.

The carbon-carbon represented by the above R ⁶ contains -OC(=O)-O-, -SC(=S)-O-, -C(=O)-N(-**)-C(=O The aliphatic heterocyclic group having at least one ring-membering number of 5 to 20 selected from the group consisting of -, -O-, and -S- is exemplified by, for example, a group having a cyclic carbonate structure and having a ring shape. A base of a dithiocarbonate structure, a group having a quinone imine structure, a group having a cyclic ether structure, a group having a cyclic thioether structure, and the like.

The above group having a cyclic carbonate structure is exemplified by, for example, 1,3-dioxo-2-oxocyclopentyl, 1,3-dioxo-2-oxocyclohexyl, 1,3-dioxan -2-oxocyclopentyl, 1,3-dioxo-2-oxocyclooctyl and the like.

The above group having a cyclic carbonate structure is exemplified by, for example, 1-thia-2-oxo-3-oxocyclopentyl, 1-thia-2-oxo-3-oxocyclohexyl, 1-2. - Oxo-3-oxepane, 1-thia-2-oxo-3-oxacyclooctyl and the like.

The above groups having a quinone imine structure are exemplified by 1,3-diaza-2-oxocyclopentyl, 1,3-diaza-2-oxocyclohexyl, and 1,3-diaza-2. - Oxocycloheptyl, 1-aza-2-oxocyclooctyl and the like.

The group having a cyclic ether structure is exemplified by, for example, an oxolyl group, an oxetanyl group, an oxetanyl group, an oxetanyl group or the like.

The group having a cyclic thioether structure is exemplified by, for example, a thiolanyl group, a thicyclohexyl group, a thietyl group, a thicyclooctyl group, and the like.

Examples of the group having a cyclic ether structure and a cyclic thioether structure are, for example, a thiooxolyl group, a thioxanthyl group, a thioxanylene group, a thioxanyl group, and the like.

A chain of carbon numbers 1 to 5, which is represented by the above R ⁶ and substituted with at least one group selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group, by replacing one or more hydrogen atoms. The chain hydrocarbon group in the hydrocarbon group is exemplified by, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, t-butyl, n-pentyl, isopentyl. An alkyl group such as a second pentyl group or a third pentyl group; an alkenyl group such as a vinyl group, a propenyl group, a butenyl group or a pentenyl group; an alkynyl group such as an ethynyl group, a propynyl group, a butynyl group or a pentynyl group; and the like.

Among these, an alkyl group is preferred, more preferably an alkyl group having 2 to 4 carbon atoms, still more preferably an ethyl group or a n-propyl group.

The chain hydrocarbon group substituted with a hydroxy group represented by the above R ⁶ is exemplified by a hydroxyalkyl group such as a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group or a hydroxypentyl group; a dihydroxyethyl group and a dihydroxypropyl group; a dihydroxyalkyl group such as a dihydroxybutyl group or a dihydroxypentyl group; a trihydroxyalkyl group such as a trihydroxypropyl group, a trihydroxybutyl group or a trihydroxypentyl group; and the like.

The chain hydrocarbon group substituted with a cyano group represented by the above R ⁶ is exemplified by a cyano group such as a cyanomethyl group, a cyanoethyl group, a cyanopropyl group, a cyanobutyl group or a cyanopentyl group; Dicyanoalkyl such as methyl, dicyanoethyl, dicyanopropyl, dicyanobutyl or dicyanopentyl; tricyanomethyl, tricyanoethyl, tricyanopropyl A tricyanoalkyl group such as a trisyl cyanobutyl group or a tricyanopentyl group.

The chain hydrocarbon group substituted with a nitro group represented by the above R ⁶ is exemplified by a nitroalkyl group such as a nitromethyl group, a nitroethyl group, a nitropropyl group, a nitrobutyl group or a nitropentyl group; Dinitroalkyl group such as methyl, dinitroethyl, dinitropropyl, dinitrobutyl or dinitropentyl; trinitromethyl, trinitroethyl, trinitropropane a trinitroalkyl group such as a trimethyl butyl group or a trinitropentyl group.

The chain hydrocarbon group substituted with a sulfonylamino group represented by the above R ⁶ is exemplified by a sulfonylamino group-substituted methyl group, a sulfonylamino group-substituted ethyl group, a sulfonylamino group-substituted propyl group, a sulfonamide. a sulfonylamino group substituted with a butyl group or a sulfonylamino group substituted with a sulfonylamino group; a methyl group substituted with a bis(sulfonylamino) group; an ethyl group substituted with a bis(sulfonylamino) group; a sulfonamide-substituted propyl group, a bis(sulfonylamino)-substituted butyl group, a bis(sulfonylamino)-substituted pentyl group, and the like, a bis(sulfonylamino)-substituted alkyl group; Amino substituted methyl, tris(sulfonylamino) substituted ethyl, tris(sulfonylamino) substituted propyl, tris(sulfonylamino) substituted butyl, tris(sulfonamide) a substituted tris(sulfonylamino)-substituted alkyl group such as a pentyl group.

The alkyl group having 1 to 5 carbon atoms which may be substituted by a fluorine atom represented by the above R ^a is exemplified by an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group; a fluoromethyl group and a difluoromethyl group; , trifluoromethyl, fluoroethyl, difluoroethyl, trifluoroethyl, pentafluoroethyl, fluoropropyl, difluoropropyl, trifluoropropyl, heptafluoropropyl, trifluorobutyl, nine Fluorobutyl, trifluoropentyl, undecafluoropentyl.

The chain hydrocarbon group substituted with an oxo group represented by the above R ⁶ is exemplified by, for example, an oxomethyl group, an oxoethyl group, an oxopropyl group, an oxybutyl group, an oxoyl group or the like; a dioxoalkyl group such as an oxoethyl group, a dioxopropyl group, a dioxobutyl group or a dioxopentyl group; a trioxo group such as a trioxopropyl group, a trioxobutyl group or a trioxopentyl group; Alkyl and the like.

The chain hydrocarbon group substituted with two or more groups selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group represented by the above R ⁶ is exemplified by, for example, a hydroxycyanoalkyl group and a hydroxyl group. Nitroalkyl, sulfonylamino substituted hydroxyalkyl, hydroxyoxyalkyl, cyanonitroalkyl, sulfonylamino substituted cyanoalkyl, cyanooxyalkyl, sulfonylamino Substituted nitroalkyl, nitrooxyalkyl, sulfonylamino substituted oxoalkyl, and the like.

An alicyclic ring having 4 to 20 carbon atoms substituted by at least one group selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group, and having 1 or more hydrogen atoms represented by the above R ⁶ The alicyclic hydrocarbon group in the hydrocarbon group is exemplified by a monocyclic cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group or a cyclododecyl group; a monocyclic cycloalkenyl group such as a cyclopentenyl group or a cyclohexenyl group; a polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group or a tetracyclododecyl group; a norbornene group; A polycyclic cycloalkenyl group such as a tricyclodecenyl group or a tetracyclododecenyl group.

An alicyclic ring having 4 to 20 carbon atoms substituted by at least one group selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group, and having 1 or more hydrogen atoms represented by the above R ⁶ The hydrocarbon group is exemplified by, for example, one of the above-exemplified alicyclic hydrocarbon groups having 4 to 20 carbon atoms exemplified by at least one selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group. A base made up of two or three hydrogen atoms.

An alicyclic ring having 4 to 20 carbon atoms substituted by at least one group selected from the group consisting of a hydroxyl group, a cyano group, a nitro group, a sulfonylamino group and an oxo group, and having one or more hydrogen atoms represented by the above R ⁶ Among the hydrocarbon groups, the adamantane skeleton is exemplified by a group represented by the following formulas (2-1-1a) to (2-1-1d).

In the above formulas (g-1) to (g-4), R ^b1 , R ^b2 and R ^{b3 are} each independently a hydroxyl group, a cyano group, a nitro group or a sulfonylamino group, and R ^a1 and R ^{a2 are} each independently a methylene group. Or a C 2~10 alkylene group, R ^a3 is a single bond, a methylene group or a C 2~10 alkyl group, c1 is an integer from 1 to 6, and c2 and c3 are each independently an integer from 1 to 15. When R ^b1 , R ^b2 and R ^{a1 are} each plural, a plurality of R ^b1 , R ^b2 and R ^a1 may be the same or different. However, * represents a bonding site with R ⁵ in the above formula (2-1).

In the above, R ⁶ is preferably a group having a cyclic carbonate structure, a group having a cyclic dithiocarbonate structure, a group having a quinone imine structure, a group having a cyclic ether structure, and having a cyclic thioether structure group, a cyclic ether structure and a thioether structure group, a hydroxy group-substituted chain hydrocarbon group, a sulfonylamino group-substituted chain hydrocarbon group, more preferably a 1,3-dioxane group 2-oxocycloalkyl, 1-thia-2-oxo-3-oxacycloalkyl, 1,3-dioxo-2-azacycloalkyl, oxacycloalkyl, thia Cycloalkyl, dithiacycloalkyl, thiooxacycloalkyl, dihydroxyalkyl, more preferably 1,3-dioxa-2-oxocyclopentyl, 1-thia-2- Oxo-3-oxocyclopentyl, 1,3-dioxo-2-azoleyl, 1,4-dithiahexyl, 1-thia-4-oxocyclohexyl, three Fluoromethylsulfonamide, dihydroxyethyl.

The structural unit (II-1) is, for example, a structural unit represented by the following formulas (2-1-1) to (2-1-16) (hereinafter also referred to as "structural unit (II-1-1) to (II) -1-16)").

In the above formulae (2-1-1) to (2-1-16), R ³ has the same meaning as the above formula (2-1).

Among these, structural units (II-1-1), structural units (II-1-2), structural units (II-1-4), structural units (II-1-6), and structural units (II- 1-7), structural unit (II-1-10), structural unit (II-1-11), structural unit (II-1-13), and structural unit (II-1-16) are preferred.

The monomer which obtained the structural unit (II-1) is, for example, a compound represented by the following (2m-1).

In the above formula (2m-1), R ³ to R ⁶ have the same meanings as in the above formula (2-1).

The monomer which obtains the structural unit (II-1) is preferably, for example, a (meth) acrylate having a cyclic carbonate structure, a (meth) acrylate having a cyclic dithiocarbonate structure, and having a quinone imine. Structure (meth) acrylate, (meth) acrylate having a cyclic thioether structure, (meth) acrylate having a cyclic ether structure and a cyclic thioether structure, (meth) acrylate having a hydroxyl group An ester, a (meth) acrylate having a sulfonamide group, (meth)acrylic acid, more preferably an alkyl (meth)acrylate containing a cyclic carbonate group, or a cyclic dithiocarbonate group ( Alkyl methacrylate, (meth) acrylate containing yttrium succinate, oxacycloalkyl (meth) acrylate , (di)alkyl (meth) acrylate, dihydroxyalkyl (meth) acrylate, hydroxycycloalkyl (meth) acrylate, alkyl sulfonamide (meth) acrylate, (Meth)acrylic acid, more preferably ethyl (meth) acrylate methyl ester methyl ester, (meth) acrylate dithiocarbonate ethyl ester methyl ester, N- (meth) propylene oxime Alkyl iminoimine, 1,4-oxathia-2-cyclohexyl (meth)acrylate, 1,4-dithia-2-cyclohexyl (meth)acrylate, (meth)acrylic acid 2 , 3-dihydroxy-1-propyl ester, trifluoromethylsulfonamide ethyl (meth)acrylate, 3-hydroxy-1-adamantyl (meth)acrylate, (meth)acrylic acid.

(structural unit (II-2))

The structural unit (II-2) is a structural unit represented by the following formula (2-2).

In the above formula (2-2), R ⁷ and R ⁸ each independently represent a hydrogen atom, a fluorine atom or a methyl group, and R ⁹ to R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but R ⁹ Two or more of ~R ¹² are bonded to each other to form a ring structure having a carbon number of 3 to 10 including the carbon atoms to be bonded, and m1 and m2 are each independently an integer of 0 to 2, and R ⁹ to R ¹² When each is plural, a plurality of R ⁹ to R ¹² may be the same or different, R ¹³ is -O- or -NR ^A -, and R ^A is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, and carbon. A cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a group in which a hydrogen atom of one of the alkyl group, the cycloalkyl group and the aryl group is substituted with a hydroxyl group or a carboxyl group.

From the viewpoint of obtaining the monomer copolymerizability of the structural unit (II-2), R ⁷ and R ⁸ are preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

The alkyl group having 1 to 5 carbon atoms represented by the above R ⁹ to R ¹² is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a second butyl group, and a third butyl group. Base, n-pentyl, isopentyl, second amyl, third amyl, neopentyl, and the like.

The ring structure of the carbon number of 3 to 10 which is formed by bonding two or more of the above R ⁹ to R ¹² to each other and the carbon atom to be bonded together is exemplified by, for example, a cyclopropane structure, a cyclobutane structure, and a cyclopentane. A monocyclic naphthenic structure such as a structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclodecane structure, or a cyclodecane structure.

A polycyclic naphthenic structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure, or a tetracyclododecane structure.

M1 and m2 are preferably 0 or 1, more preferably 0.

The above R ^{13 is} preferably -NR ^A -.

The alkyl group having 1 to 5 carbon atoms represented by R ^A is exemplified by the same groups as those exemplified as the above R ⁹ to R ¹² .

The cycloalkyl group having 4 to 20 carbon atoms represented by the above R ^A is exemplified by a monocyclic cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cyclooctyl group; a norbornyl group, an adamantyl group, and a tricyclic group; a polycyclic cycloalkyl group such as a cyclodecyl group or a tetracyclododecyl group.

The aryl group having 6 to 20 carbon atoms represented by the above R ^A is exemplified by, for example, phenyl, tolyl, xylyl, mesitylene, fluorophenyl, chlorophenyl, naphthyl, methylnaphthyl, anthracenyl. , methyl thiol and the like.

The group in which the hydrogen atom of one of the alkyl group, the cycloalkyl group and the aryl group is substituted with a hydroxyl group is exemplified by, for example, a hydroxyethyl group, a hydroxypropyl group, a hydroxycyclopentyl group, a hydroxycyclohexyl group, a hydroxyphenyl group, a hydroxynaphthyl group or the like.

The group in which a hydrogen atom of one of the alkyl group, the cycloalkyl group and the aryl group is substituted with a carboxyl group is exemplified by a carboxymethyl group, a carboxyethyl group, a carboxycyclopentyl group, a carboxycyclohexyl group, a carboxyphenyl group or a carboxynaphthyl group.

The structural unit (II-2) is exemplified by a structural unit represented by the following formula (2-2-1) to (2-2-8) (hereinafter also referred to as "structural unit (II-2-1) ~ ( II-2-8)") and so on.

In the above formulae (2-2-1) to (2-2-8), R ⁷ and R ⁸ have the same meanings as in the above formula (2-2).

Among these, it is preferable to have a structural unit (II-2-2) and a structural unit (II-2-3).

The monomer obtained in the structural unit (II-2) is exemplified by a compound represented by the following formula (2m-2).

In the above formula (2m-2), R ⁷ to R ¹³ and m1 and m2 have the same meanings as in the above formula (2-2).

The monomer which obtains the structural unit (II-2) is preferably a maleic imine compound or a maleic anhydride compound, more preferably maleic imide or maleic anhydride.

(structural unit (II-3))

The structural unit (II-3) is a structural unit represented by the following formula (2-3).

In the above formula (2-3), R ¹⁴ is a hydrogen atom or a methyl group, and R ¹⁵ to R ^{18 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but two or more of R ¹⁵ to R ¹⁸ Bonding to each other to form a ring structure containing carbon atoms of the bonded carbon atoms of 3 to 10, n1 and n2 are each independently an integer of 0 to 2, and when each of R ¹⁵ to R ¹⁸ is plural, a plurality of R ¹⁵ to R ¹⁸ may be the same or different, R ¹⁹ is -O- or -NR ^B -, and R ^B is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, An aryl group having 6 to 20 carbon atoms or a group in which a hydrogen atom of one of the alkyl group, the cycloalkyl group and the aryl group is substituted with a hydroxyl group or a carboxyl group.

As for the above R ¹⁴ , from the viewpoint of obtaining the monomer copolymerizability of the structural unit (II-3), a hydrogen atom is preferred.

The alkyl group having 1 to 5 carbon atoms represented by the above R ¹⁵ to R ¹⁸ is, for example, the same as the alkyl group as the carbon number 1 to 5 represented by R ⁹ to R ¹² in the above formula (2-2). Base.

The ring structure of the carbon number of 3 to 10 in which two or more of R ¹⁵ to R ¹⁸ are bonded to each other and the carbon atoms bonded thereto is exemplified as, for example, R ⁹ ~ in the above (2-2). The ring structure formed by bonding two or more of R ¹² to each other is the same as the base.

The above n1 and n2 are preferably 0 or 1, more preferably 0.

As for R ¹⁹ above, it is preferably -NR ^B -.

The alkyl group having 1 to 5 carbon atoms, the cycloalkyl group having 4 to 20 carbon atoms, the aryl group having 6 to 20 carbon atoms, and a part of hydrogen atoms of the alkyl group, the cycloalkyl group and the aryl group represented by the above R ^B The group substituted with a hydroxyl group or a carboxyl group is exemplified by the same groups as those exemplified as R ^A in the above formula (2-1).

The structural unit (II-3) is exemplified by a structural unit represented by the following formula (2-3-1) to (2-3-8) (hereinafter also referred to as "structural unit (II-3-1)~ (II-3-8)") and so on.

In the above formulas (2-3-1) to (2-3-8), R ¹⁴ has the same meaning as the above formula (2-3).

Among these, the structural unit (II-3-1), the structural unit (II-3-2), and the structural unit (II-3) are preferred, and more preferably the structural unit (II-3-1).

The monomer which obtained the structural unit (II-3) is a compound represented by the following formula (2m-3), etc., for example.

In the above formula (2m-3), R ¹⁴ to R ¹⁹ and n1 and n2 have the same meanings as in the above formula (2-3).

The monomer which obtains the structural unit (II-3) is preferably a methylene succinic anhydride compound or a methylene succinic acid imide compound, more preferably a methylene succinic anhydride compound, more preferably methylene succinic anhydride. .

The lower limit of the content ratio of the structural unit (II) in the polymer [A] is preferably 10 mol%, more preferably 20 mol%, still more preferably 35 mol%, and most preferably 45 mol%. On the other hand, the upper limit of the content ratio of the structural unit (II) is preferably 90 mol%, more preferably 80 mol%, still more preferably 65 mol%, and most preferably 55 mol%. When the content ratio of the structural unit (II) is less than the above lower limit, the contrast before and after the development is reduced, and the pattern formation property is lowered. When the content ratio of the structural unit (II) exceeds the above upper limit, the pattern formation property of the photoresist composition (I) may be lowered.

[A] The total content ratio of the structural unit (I) and the structural unit (II) in the polymer is 90 mol% or more, preferably 95 mol% or more, more preferably 98 mol% or more, and still more Good for 100% of the mole. When the total content ratio of the structural unit (I) and the structural unit (II) does not reach the above lower limit, the LWR performance, the resolution, and the rectangular shape of the cross-sectional shape of the photoresist composition (I) may be lowered.

[Other construction units]

The [A] polymer may have other structural units in addition to the above structural unit (I) and structural unit (II). Other structural units are exemplified by, for example, a structural unit containing a non-acid dissociable monovalent alicyclic hydrocarbon group. The etching resistance of the formed photoresist pattern can be improved by the structural unit having the above-mentioned non-acid dissociable monovalent alicyclic hydrocarbon group. The [A] polymer may have one or more other structural units. The total content of the other structural units is preferably 10 mol% or less, more preferably 5 mol% or less, based on the total structural unit of the [A] polymer.

Further, the [A] polymer preferably does not substantially contain at least one structural unit (hereinafter also referred to as "structural unit (0)") including at least one selected from the group consisting of a lactone structure and a sultone structure. In the structural unit (0), the lactone ring or the like may be opened due to impurities contained in the resist composition, and the reactivity may be high, so that the storage stability of the photoresist composition may be affected. Further, since the structural unit (0) has a tendency to agglomerate in the polymer due to the other monomers copolymerized, the solubility of the [A] polymer becomes uneven, and the inhibition of the development defect is caused. The situation of influence. According to this, by making the [A] polymer substantially have no structural unit (0), it is possible to improve the storage stability of the photoresist composition (I), suppress the development defects, and reduce the cost.

The [A] polymer has substantially no structural unit (0) means that, for example, the content ratio of the structural unit (0) is 10 mol% or less with respect to all the structural units constituting the [A] polymer. The content ratio of the structural unit (0) is preferably 5 mol% or less, more preferably 3 mol% or less, more preferably 1 mol% or less, and most preferably 1 mol% or less, based on the total structural unit of the [A] polymer. For 0.1 Less than or equal to the ear, and preferably 0% by mole.

<[A] Synthesis Method of Polymer>

The [A] polymer can be produced by, for example, polymerizing a monomer corresponding to each specific structural unit in a suitable solvent using a radical polymerization initiator.

The above radical polymerization initiators are exemplified by azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'- Azo such as azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate a radical initiator; a peroxide-based radical polymerization initiator such as benzammonium peroxide, tert-butyl hydroperoxide or cumyl hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred. These radical initiators may be used singly or in combination of two or more.

The solvent used in the above polymerization is exemplified by, for example, an alkane such as n-pentane, n-hexane, n-heptane, n-octane, n-decane or n-decane; cyclohexane, cycloheptane, cyclooctane, and decahydrogen; Naphthenes such as naphthalene and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and cumene; chlorobutanes, bromohexanes, dichloroethanes, hexamethylene Halogenated hydrocarbons such as dibromo and chlorobenzene; saturated carbonates such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; acetone, methyl ethyl ketone, 4-methyl-2-pentyl a ketone such as a ketone or a 2-heptanone; Ethers such as tetrahydrofuran, dimethoxyethane and diethoxyethane; alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. These solvents may be used singly or in combination of two or more.

The reaction temperature in the above polymerization is usually from 40 to 150 ° C, preferably from 50 ° C to 120 ° C. The reaction time is usually from 1 hour to 48 hours, preferably from 1 hour to 24 hours.

[A] The polystyrene-equivalent weight average molecular weight (Mw) measured by a gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 500,000 or less, more preferably 2,000 or more and 400,000 or less. Good for 3,000 or more and 300,000 or less. When the Mw of the [A] polymer does not reach the above lower limit, the heat resistance of the obtained resist film may be lowered. On the other hand, when the Mw of the [A] polymer exceeds 500,000, the developability of the resist film may be lowered.

The ratio (Mw/Mn) of the Mw of the polymer to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, more preferably 1 Above 2 or less.

The content of the [A] low molecular weight component (meaning component having a molecular weight of less than 1,000) in the polymer is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, still more preferably 0.1% by mass or less. By setting the content of the low molecular weight component in the above range, the LWR performance and the like of the photoresist composition (I) can be further improved.

[B] An acid generating system produces an acid substance by exposure of electromagnetic waves or charged particle beams. Using the acid produced above to store [A] polymer When the acid dissociable group dissociates to form a polar group such as a carboxyl group, the [A] polymer becomes insoluble to the developing solution. Here, the electromagnetic wave is exemplified by ultraviolet rays, visible rays, far ultraviolet rays, X-rays, γ rays, and the like, and the charged particle beam is exemplified by an electron beam or an α-ray. The form of the [B] acid generator in the photoresist composition (I) may be a compound form as described later (hereinafter sometimes referred to as "[B] acid generator" as appropriate), or may be a polymer. A part of the form of the acid generating group may also be in the form of the second.

The [B] acid generator is exemplified by, for example, an onium salt compound, an N-sulfonyloxyquinone imine compound, a halogen-containing compound, a diazoketone compound, and the like. Among the [B] acid generators, an onium salt compound is preferred.

The onium salt compound is exemplified by, for example, an onium salt, a tetrahydrothiophene salt, a phosphonium salt, a phosphonium salt, a diazonium salt, a pyridinium salt or the like.

The onium salt is exemplified by, for example, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium perfluorooctanesulfonate, triphenylsulfonium 2-bicyclo[ 2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenyl camphorsulfonate, 4-cyclohexylphenyldiphenylphosphonium trifluoromethanesulfonic acid Salt, 4-cyclohexylphenyldiphenylphosphonium nonafluorobutane sulfonate, 4-cyclohexylphenyldiphenylphosphonium perfluorooctane sulfonate, 4-cyclohexylphenyldiphenylphosphonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylcamphorsulfonate, 4-methanesulfonate Phenyldiphenylphosphonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium nonafluorobutanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium perfluorocarbon Octanesulfonate, 4-methanesulfonylphenyldiphenylphosphonium 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4- Methanesulfonylphenyldiphenyl camphor Sulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6-(1-adamantanecarbonyloxy)-hexane-1-sulfonate, triphenylsulfonium 2-(1-gold Alkyl)-1,1-difluoroethanesulfonate, triphenylsulfonium 2-(adamantane-1-ylcarbonyloxy)-1,1,3,3,3-pentafluoropropane-1- Sulfonate and the like.

The tetrahydrothiophene sulfonium salt is exemplified by, for example, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetra Hydrogenthiophene nonafluoro-n-butane sulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene fluorene perfluorooctane sulfonate, 1-(4-n-butoxynaphthalene) -1-yl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(4-n-butoxynaphthalene- 1-yl)tetrahydrothiophene camphorsulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene hexafluoropropyl sulfonimide, 1-(6-n-butoxy Naphthyl-2-yl)tetrahydrothiophene trifluoromethanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(6 n-Butoxynaphthalen-2-yl)tetrahydrothiophene fluorene perfluoro-n-octane sulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene 2-cyclo[2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(6-n-butoxynaphthalen-2-yl)tetrahydrothiophene camphorsulfonate, 1-(6 -n-butoxynaphthalen-2-yl)tetrahydrothiophene hexafluoro-propenylsulfonimide, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene trifluoromethanesulfonate Acid salt, 1-(3,5-dimethyl-4-hydroxyl Tetrahydrothiophene nonafluoro-n-butane sulfonate, 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene perfluorooctane sulfonate, 1-(3, 5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene 2-cyclobi[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1-(3 ,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene camphorsulfonate, etc., 1-(3,5-dimethyl-4-hydroxyphenyl)tetrahydrothiophene tetrahydrothiophene hexafluoro Propylsulfonimide and the like.

The onium salt is exemplified by, for example, diphenylsulfonium trifluoromethanesulfonate, diphenylsulfonium nonafluorobutanesulfonate, diphenylphosphonium perfluorooctanesulfonate, diphenylphosphonium 2-bicyclopropane. [2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, diphenyl camphorsulfonate, bis(4-t-butylphenyl)phosphonium trifluoride Methanesulfonate, bis(4-t-butylphenyl)phosphonium nonafluorobutane sulfonate, bis(4-t-butylphenyl)phosphonium perfluoro-n-octane sulfonate, double (4 -T-butylphenyl)indole 2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis(4-t-butylphenyl) Camphor sulfonate and the like.

The N-sulfonyloxyimide compound is exemplified by, for example, N-(trifluoromethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimideimine, N-(nine Fluorine butane sulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimenine, N-(perfluoro-n-octanesulfonyloxy)bicyclo[2.2.1] Hg-5-ene-2,3-dicarboxylimenine, N-(2-bicyclo[2.2.1]hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyarsenine, N-(2-(3-tetracyclo[4.4.0.1 ^2,5 .1 ^7,10 ]dodecyl] -1,1-difluoroethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylimenine, N-(camanosylsulfonyloxy)bicyclo[2.2. 1] Hept-5-ene-2,3-dicarboxylimenine and the like.

As the [B] acid generator, among these, a phosphonium salt is preferred, more preferably a phosphonium salt or a tetrahydrothiophene salt, and more preferably a triphenylsulfonium salt or a 1-(4-n-butoxynaphthalene) salt. -1-yl) tetrahydrothiophene sulfonium salt, preferably triphenylsulfonium 2-(1-adamantyl)-1,1-difluoroethanesulfonate, triphenylsulfonium 2-(adamantane- 1-ylcarbonyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonate, 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene hexafluoroexene Propylsulfonimide.

The [B] acid generators may be used singly or in combination of two on. [B] The content of the acid generator in the case of an acid generator is usually 0.1 parts by mass or more and 30 parts by mass with respect to 100 parts by mass of the [A] polymer, from the viewpoint of sensitivity and development of the resist. Hereinafter, it is preferably 0.5 parts by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less. In this case, when the content of the [B] acid generator is less than 0.1 part by mass, the sensitivity and the developing property tend to be lowered. On the other hand, when the content exceeds 30 parts by mass, the transparency to the radiation is lowered, which is difficult. The tendency to obtain the desired photoresist pattern.

<[C] Acid Diffusion Control Body>

[C] The acid diffusion control body controls the diffusion of the acid generated from the [B] acid generator by the exposure film in the resist film, and exhibits an effect of suppressing a poor chemical reaction in the unexposed region, and the light can be further improved. The storage stability of the composition is further improved, and the resolution as the photoresist is further improved, and the line width variation of the photoresist pattern due to the change of the standing time from the exposure to the development processing is suppressed, and the process stability is excellent. Composition. [C] The form of the acid diffusion controlling body in the photoresist composition (I) may be in the form of a free compound (hereinafter also referred to as [C] acid diffusion controlling agent), or may be incorporated in one part of the polymer. The form can also be the form of the two.

The [C] acid diffusion controlling agent is exemplified by, for example, an amine compound, a guanamine group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound, and the like.

The amine compounds are exemplified by, for example, mono(cyclo)alkylamines; di(cyclo)alkylamines; tri(cyclo)alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N , N', N'-tetramethylethylenediamine, tetramethylenediamine, Hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4' -diaminodiphenylamine, 2,2-bis(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2-( 4-aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, 1,4-bis(1-( 4-aminophenyl)-1-methylethyl)benzene, 1,3-bis(1-(4-aminophenyl)-1-methylethyl)benzene, bis(2-dimethylamine) Ethyl ethyl ether, bis(2-diethylaminoethyl) ether, 1-(2-hydroxyethyl)-2-imidazolidinone, 2-quinoxaline alcohol, N,N,N',N '-肆(2-hydroxypropyl)ethylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, and the like.

As the amide group-containing compound, for example, an N-tert-butoxycarbonyl group-containing amine compound, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, acetamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-ethinyl-1-adamantanamine, isocyanide Tris(2-hydroxyethyl) urate and the like.

Urea compounds are exemplified by, for example, urea, methyl urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea , tri-n-butyl thiourea, and the like.

The nitrogen-containing heterocyclic compound is exemplified by, for example, imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinazoline, anthracene, pyrrolidine, piperidine, piperidine ethanol, 3-piperidinyl-1 , 2-propanediol, morpholine, 4-methylmorpholine, 1-(4-morpholinyl)ethanol, 4-ethylmercaptomorpholine, 3-(N-morpholinyl)-1,2-propanediol, 1,4-Dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, and the like.

Also, as a [C] acid diffusion control agent, it can also be used by exposure Light-sensitive to produce a light-disinfecting base of weak acid. The photocracking base increases the insolubility of the [A] polymer to the developing solution by generating an acid in the exposed portion, and as a result, suppresses the roughness of the surface of the exposed portion after development. On the other hand, in the unexposed portion, a function as a quenching agent having a high acid capturing function obtained by an anion is exhibited, and an acid diffused from the exposed portion is captured. That is, since it functions as a quenching agent only in the unexposed portion, the contrast of the deprotection reaction is improved, and as a result, the resolution can be further improved. An example of a photodisintegration base is an onium salt compound which loses acid diffusion controllability by exposure decomposition. The onium salt compound is exemplified by an onium salt compound represented by the following formula (C1), an onium salt compound represented by the following formula (C2), and the like.

In the above formula (C1) and formula (C2), R ²⁰ to R ²⁴ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom or -SO ₂ -R ^A . R ^A is an alkyl group, a cycloalkyl group, an alkoxy group or an aryl group. Z ^- is OH ^- , R ^B -COO ^- , R ^C -SO ₂ -N ^- -R ^B , R ^B -SO ₃ ^- or an anion represented by the following formula (C3). R ^B is a linear or branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, and an aralkyl group having 7 to 30 carbon atoms. Some or all of the hydrogen atoms of the above alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted. R ^C is a linear or branched alkyl group having 1 to 10 carbon atoms, and a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. Some or all of the hydrogen atoms of the above alkyl group and cycloalkyl group may be substituted with a fluorine atom. However, when Z ^- is R ^B -SO ₃ ^- , there is no case where a fluorine atom is bonded to a carbon atom bonded to the SO ₃ ^- bond.

In the above formula (C3), R ²⁵ is a linear or branched alkyl group having 1 to 12 carbon atoms or a linear or branched carbon number of 1 to 12 which is partially or wholly substituted by a fluorine atom. Alkoxy group. u is an integer from 0 to 2.

The above R ²⁰ to R ^{24 are} preferably a hydrogen atom and -SO ₂ -R ^A . Further, the above R ^{A is} preferably a cycloalkyl group, more preferably a cyclohexyl group.

The alkyl group represented by the above R ^B is exemplified by, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, and a part or all of the hydrogen atoms of the groups are substituted. Base.

The cycloalkyl group represented by the above R ^B is exemplified by, for example, a cyclopentyl group, a cyclohexyl group, a norbornyl group, a tricyclodecyl group, a tetracyclododecyl group, an adamantyl group, and a part or all of hydrogen atoms of the groups. Substituted bases, etc.

The aryl group represented by the above R ²⁵ is exemplified by, for example, a phenyl group, a naphthyl group, an anthryl group or the like, and a partially or wholly substituted group of one of the hydrogen atoms of the groups.

The aralkyl group represented by the above R ²⁵ is exemplified by, for example, a benzyl group, a phenethyl group, a phenylpropyl group, and a partially or wholly substituted group of hydrogen atoms of the groups.

The substituent of the above alkyl group, cycloalkyl group, aryl group and aralkyl group is exemplified by a hydroxyl group, a halogen atom, an alkoxy group, a lactone group, an alkylcarbonyl group and the like.

The alkyl group represented by the above R ^C is exemplified by a methyl group, an ethyl group, a propyl group, a butyl group or the like.

The cycloalkyl group represented by the above R ^C is exemplified by, for example, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group or the like.

The photocracking base is exemplified by a compound represented by the following formula.

In the photoresist composition (I), the content of the [C] acid diffusion control body, When the [C] acid diffusion controlling agent is the [C] acid diffusion controlling agent, it is preferably 10 parts by mass or less based on 100 parts by mass of the [A] polymer. When the content of the [C] acid diffusion controlling agent exceeds 10 parts by mass, the sensitivity as a resist tends to decrease. These acid diffusion inhibitors may be used alone or in combination of two or more.

<[D] Polymer of fluorine atom>

The photoresist composition (I) may contain a polymer of [D] fluorine atom (except for [A] polymer). When the photoresist composition (I) contains a polymer of [D] fluorine-containing atom, when the resist film is formed, the distribution of the polymer of the fluorine atom is biased to the resist. Since the tendency of the film surface layer is suppressed, the acid generator or the acid diffusion controlling agent in the film can be dissolved in the liquid immersion medium when the liquid immersion exposure is suppressed. Further, by the water repellency characteristic of the polymer of the [D] fluorine-containing atom, the contact angle of the resist film and the liquid immersion medium can be controlled within a desired range, and generation of bubble defects can be suppressed. Further, the back contact angle of the resist film and the liquid immersion medium can be increased, and as a result, no water droplets remain, making it possible to perform high-speed scanning exposure. Thus, by making the photoresist composition (I) contain a polymer of [D] fluorine atom, a resist film suitable for liquid immersion exposure can be formed.

The polymer of the fluorine atom-containing polymer is not particularly limited as long as it is a polymer containing a fluorine atom, but it can be usually formed by polymerizing a monomer having a fluorine atom in one or more structures. The monomer having a fluorine atom in the structure is exemplified as a fluorine atom in the main chain, a fluorine atom in the side chain, and a fluorine atom in the main chain and the side chain.

The monomer having a fluorine atom in the above main chain is exemplified by, for example, an α-fluoroacrylate compound, an α-trifluoromethacrylate compound, and β-fluoropropene. Acid ester compound, β-trifluoromethacrylate compound, α,β-fluoroacrylate compound, α,β-trifluoromethacrylate compound, hydrogen of one or more vinyl sites via fluorine atom or trifluoro A compound such as a methyl group or the like.

The monomer having a fluorine atom on the side chain is exemplified by, for example, a side chain in which an alicyclic hydrocarbon compound of norbornene is a fluorine atom or a fluoroalkyl group or a derivative thereof, or an acrylic acid or methacrylic acid and a fluoroalkanol or The ester compound formed by the derivative and the side chain (the site containing no double bond) of one or more kinds of olefins are fluorine atoms or fluoroalkyl groups or derivatives thereof.

The monomer having a fluorine atom in the main chain and the side chain is exemplified by, for example, α-fluoroacrylic acid, β-fluoroacrylic acid, α,β-fluoroacrylic acid, α-trifluoromethacrylic acid, β-trifluoromethacrylic acid, An ester compound formed of a fluoroalkanol or a derivative thereof, such as α,β-di-trifluoromethacrylic acid, or a side chain of a compound in which one or more vinyl sites are substituted with a fluorine atom or a trifluoromethyl group or the like a fluorine atom or a fluoroalkyl group or a derivative thereof, wherein one or more hydrogens bonded to a double bond of the alicyclic olefin compound are substituted with a fluorine atom or a trifluoromethyl group, and the side chain is a fluoroalkyl group or Its derivatives and so on. Further, the alicyclic olefin compound is a compound in which a part of the ring is a double bond.

The polymer of the [D] fluorine-containing atom preferably has a structural unit represented by the following formula (D1) (hereinafter also referred to as "structural unit (D-1)").

In the above formula (D1), R ²⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. A is a single bond or a divalent linking group, and R ²⁷ is a linear or branched alkyl group having 1 to 6 carbon atoms having at least one fluorine atom, or a carbon number of 4 to 20 having at least one fluorine atom. A monovalent alicyclic hydrocarbon group or a derivative thereof.

The divalent linking group represented by the above A may, for example, be an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, a decylamino group, a sulfonylamino group or a urethane group.

Preferred monomers for obtaining the above structural unit (D-1) are exemplified by trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, and perfluoroethylene (meth)acrylate. Ester, perfluoro-n-propyl (meth)acrylate, perfluoroisopropyl (meth)acrylate, perfluoro-n-butyl (meth)acrylate, perfluoroisobutyl (meth)acrylate, (methyl) Perfluorotributyl acrylate, 2-(1,1,1,3,3,3-hexafluoropropyl) (meth)acrylate, 1-(2,2,3,3 (meth)acrylate ,4,4,5,5-octafluoropentyl)ester, perfluorocyclohexylmethyl (meth)acrylate, 1-(2,2,3,3,3-pentafluoropropyl (meth)acrylate ) ester, 1-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoroindolyl (meth)acrylate An ester, 1-(5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluorohexyl) (meth)acrylate or the like.

[D] The content ratio of the structural unit (D-1) in the polymer containing a fluorine atom is usually 5 mol% or more, preferably 5 mol% or more, based on the total structural unit of the polymer constituting the [D] fluorine atom. It is 10 mol% or more, more preferably 15 mol% or more. When the content ratio of the structural unit (D-1) is less than 5 mol%, the retraction contact angle of 70° or more cannot be achieved, and the self-resistance film such as an acid generator cannot be suppressed from eluting. The polymer of the [D] fluorine atom may contain one or more structural units (D-1).

The polymer of the fluorine atom-containing polymer may contain, in addition to the structural unit having the fluorine atom in the structure, one or more structural units having an acid dissociable group for controlling the dissolution rate of the developing solution. A structural unit having a hydroxyl group or a carboxyl group, a structural unit having an alicyclic compound, and a "other structural unit" for suppressing light scattering due to reflection from a substrate and a structural unit derived from an aromatic compound.

The structural unit having the acid-dissociable group is exemplified by a structural unit represented by the following formula (D2) (hereinafter also referred to as "structural unit (D-II)").

In the above formula (D2), R ²⁸ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^q1 to R ^{q3 are} each independently a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms.

The monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by the above R ^q1 to R ^q3 is exemplified by, for example, norbornane, tricyclodecane, tetracyclododecane, adamantane or cyclobutane, cyclopentane. a group of an alicyclic ring such as a cycloalkane such as an alkane, a cyclohexane, a cycloheptane or a cyclooctane; or a part or all of a hydrogen atom derived from a group of the alicyclic ring via, for example, a methyl group or an ethyl group; , a straight or branched alkyl group having a carbon number of 1 to 4, such as n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl or t-butyl, or a ring One or more or one or more substituted groups of a cycloalkyl group having 3 to 10 carbon atoms such as a butyl group or a cyclohexyl group. Further, any of R ^q1 to R ^q3 may be bonded to each other to form a divalent alicyclic hydrocarbon group or a derivative thereof. Among the alicyclic hydrocarbon groups, preferably derived from, or derived from, an alicyclic ring derived from norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclopentane or cyclohexane The hydrogen atom of the group such as the alicyclic ring is substituted with the above alkyl group.

The linear or branched alkyl group having 1 to 4 carbon atoms represented by the above R ^q1 to R ^q3 is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group or a 2-methyl group. Base, 1-methylpropyl, tert-butyl, and the like.

The group represented by -C(R ^q1 )(R ^q2 )(R ^q3 ) in the above formula (D2) is exemplified by, for example, a third butyl group, 1-n-(1-ethyl-1-methyl)propyl group. , 1-n-(1,1-dimethyl)propyl, 1-n-(1,1-dimethyl)butyl, 1-n-(1,1-dimethyl)pentyl, 1 -(1,1-diethyl)propyl, 1-n-(1,1-diethyl)butyl, 1-n-(1,1-diethyl)pentyl, 1-(1- Methyl)cyclopentyl, 1-(1-ethyl)cyclopentyl, 1-(1-n-propyl)cyclopentyl, 1-(1-isopropyl)cyclopentyl, 1-(1- Methyl)cyclohexyl, 1-(1-ethyl)cyclohexyl, 1-(1-n-propyl)cyclohexyl, 1-(1-isopropyl)cyclohexyl, 1-{1-methyl-1 -(2-norbornyl)}ethyl, 1-{1-methyl-1-(2-tetracycloindenyl)}ethyl, 1-{1-methyl-1-(1-adamantyl) )} ethyl, 2-(2-methyl)norbornyl, 2-(2-ethyl)norbornyl, 2-(2-n-propyl)norbornyl, 2-(2-isopropyl )norbornyl, 2-(2-methyl)tetracyclodecyl, 2-(2-ethyl)tetracyclodecyl, 2-(2-n-propyl)tetracyclodecyl, 2-(2- Isopropyl)tetracyclinyl, 1-(1-methyl)adamantyl, 1-(1-ethyl)adamantyl, 1-(1-n-propyl)adamantyl, 1-(1 -isopropyl)adamantyl, or a group derived from such alicyclic rings For example, a linear or branched carbon number of 1 to 4 such as methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1-methylpropyl or t-butyl. The alkyl group or one of the cyclic alkyl groups having 3 to 10 carbon atoms or one or more substituted groups.

The monomer which obtains the structural unit (D-II) is exemplified by, for example, 2-methyladamantan-2-yl (meth)acrylate, 2-methyl-3-hydroxyadamantane-2-(meth)acrylate Base ester, 2-ethyladamantan-2-yl (meth)acrylate, 2-ethyl-3-hydroxyadamantan-2-yl (meth)acrylate, 2-n-propyl (meth)acrylate Fundane-2-yl ester, 2-isopropyladamantan-2-yl (meth)acrylate, 2-methylbicyclo[2.2.1]hept-2-yl (meth)acrylate, 2-ethylbicyclo[2.2.1]hept-2-yl methacrylate, 8-methyltricyclo[5.2.1.0 ^2,6 ]non-8-yl (meth) acrylate, (methyl) Acetyl-8-ethyltricyclo[5.2.1.0 ^2,6 ]non-8-yl ester, 4-methyltetracyclo(methyl)acrylate [6.2.1 ^3,6 .0 ^2,7 ]12 Alkyl-4-yl ester, 4-ethyltetracyclo(methyl)acrylate [6.2.1 ^3,6 .0 ^2,7 ]dodecan-4-yl ester, 1-(bicyclo)[(meth)[ 2.2.1] Hept-2-yl)-1-methylethyl ester, 1-(tricyclo[5.2.1.0 ^2,6 ]non-8-yl)-1-methylethyl (meth)acrylate Ester, 1-(tetracyclo[6.2.1 ^3,6 .0 ^2,7 ]dodecan-4-yl)-1-methylethyl (meth)acrylate, 1-(meth)acrylate Adamantan-1-yl)-1-methylethyl ester, (A ) 1-(3-hydroxyadamantan-1-yl)-1-methylethyl acrylate, 1,1-dicyclohexylethyl (meth)acrylate, 1,1-di(meth)acrylate (Bicyclo[2.2.1]hept-2-yl)ethyl ester, 1,1-di(tricyclo[5.2.1.0 ^2,6 ]non-8-yl)ethyl (meth)acrylate, (A) 1,1-di(tetracyclo[6.2.1 ^3,6 .0 ^2,7 ]dodecan-4-yl)ethyl acrylate, 1,1-di(adamantane) (meth) acrylate 1-yl)ethyl ester, 1-methyl-1-cyclopentyl (meth)acrylate, 1-ethyl-1-cyclopentyl (meth)acrylate, 1-methyl (meth)acrylate Alkyl-1-cyclohexyl ester, 1-ethyl-1-cyclohexyl (meth)acrylate, and the like.

Among these monomers, 2-methyladamantan-2-yl (meth)acrylate, 2-ethyladamantan-2-yl (meth)acrylate, and 2-(meth)acrylic acid are preferred. Methylbicyclo[2.2.1]hept-2-yl ester, 2-ethylbicyclo[2.2.1]hept-2-yl (meth)acrylate, 1-(bicyclo[2.2.1] ]hept-2-yl)-1-methylethyl ester, 1-(adamantan-1-yl)-1-methylethyl (meth)acrylate, 1-methyl-(meth)acrylate 1-cyclopentyl ester, 1-ethyl-1-cyclopentyl (meth)acrylate, 1-methyl-1-cyclohexyl (meth)acrylate, 1-ethyl (meth)acrylate 1-cyclohexyl ester.

The structural unit having the alicyclic group (hereinafter also referred to as "structural unit (D-III)") is exemplified by a structural unit represented by the following formula (D4).

In the above formula (D4), R ²⁹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³⁰ is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.

The monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by the above R ³⁰ is exemplified by, for example, cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, and bicyclo [2.2.2]. ] octane, tricyclo[5.2.1.0 ^2,6 ]decane, tetracyclo[6.2.1.1 ^3,5 .0 ^2,7 ]dodecane, tricyclo[3.3.1.1 ^3,7 ]decane, etc. a hydrocarbon group of an alicyclic ring of an alkane. The hydrocarbon group derived from the cycloaliphatic alicyclic ring may have a substituent, for example, may also be methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-methylpropyl, 1- One or more or one or more substituents of a linear or branched alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 3 to 10 carbon atoms such as a methyl propyl group and a third butyl group. The substituent is not limited to the alkyl group and the cycloalkyl group, and may be a hydroxyl group, a cyano group, a hydroxyalkyl group having 1 to 10 carbon atoms, a carboxyl group or an oxo group.

The monomer which obtains the structural unit (D-III) is exemplified by, for example, bicyclo[2.2.1]hept-2-yl (meth)acrylate and bicyclo[2.2.2]oct-2-yl (meth)acrylate. , (cyclo)-(meth)acrylic acid [5.2.1.0 ^2,6 ]癸-7-yl ester, tetramethyl (meth)acrylate [6.2.1.1 ^3,6 .0 ^2,7 ]dodecane-9-yl Ester, tricyclo[3.3.1.1 ^3,7 ]non-1-yl (meth)acrylate, tricyclo[3.3.1.1 ^3,7 ]non-2-yl (meth)acrylate, and the like.

The monomer obtained by the structural unit derived from the above aromatic compound (hereinafter also referred to as "structural unit (D-IV)") is exemplified by, for example, styrene, α-methylstyrene, 2-methylstyrene, 3 -methylstyrene, 4-methylstyrene, 2-methoxystyrene, 3-methoxystyrene, 4-methoxystyrene, 4-(2-t-butoxycarbonylethyl) Oxy)styrene, 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2-hydroxy-α-methylstyrene, 3-hydroxy-α-methylstyrene, 4-hydroxy- --methylstyrene, 2-methyl-3-hydroxystyrene, 4-methyl-3-hydroxystyrene, 5-methyl-3-hydroxystyrene, 2-methyl-4-hydroxystyrene , 3-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene, 2,4,6-trihydroxystyrene, 4-tert-butoxystyrene, 4-tert-butoxy- Α-methylstyrene, 4-(2-ethyl-2-propoxy)styrene, 4-(2-ethyl-2-propoxy)-α-methylstyrene, 4-(1) -ethoxyethoxy)styrene, 4-(1-ethoxyethoxy)-α-methylstyrene, phenyl (meth)acrylate, benzyl (meth)acrylate, decene, 5-hydroxydecene, 1-vinyl Naphthalene, 2-vinylnaphthalene, 2-hydroxy-6-vinylnaphthalene, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, 1-naphthyl (meth)acrylate Ester, 1-decyl (meth)acrylate, 2-decyl (meth)acrylate, 9-decyl (meth)acrylate, 9-fluorenyl (meth)acrylate, 1-ethylene Inclusion of dinaphthalene and the like.

[D] The fluorine atom-containing polymer may have one or more structural units (D-II), a structural unit (D-III), a structural unit (D-IV), and a structural unit (DV) as the above. Other structural units. The total of the other structural units described above is contained in a ratio relative to the polymer constituting the [D] fluorine-containing atom. All structural units are usually 80 mol% or less, preferably 75 mol% or less, more preferably 70 mol% or less.

The content of the polymer of the [D] fluorine atom is preferably 20 parts by mass or less, more preferably 0.1 part by mass to 15 parts by mass, even more preferably 1 part by mass, per 100 parts by mass of the [A] polymer. 10 parts by mass, preferably 1 part by mass to 6 parts by mass. When the content of the polymer of the fluorine-containing atom exceeds the above upper limit, the water repellency on the surface of the resist film may be too high to cause development failure.

The fluorine atom content of the [D] fluorine atom-containing polymer is preferably larger than the [A] polymer fluorine atom content. When the fluorine atom content in the polymer of the fluorine atom-containing polymer is larger than that of the [A] polymer, the photoresist composition of the polymer containing the [A] polymer and the [D] fluorine-containing atom can be further improved. The water repellency of the surface of the resist film formed. The difference between the fluorine atom content of the polymer of the fluorine-containing atom and the fluorine atom content of the [A] polymer is preferably 1% by mass or more, more preferably 3% by mass or more.

Further, the fluorine atom content of the polymer of the [D] fluorine atom is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and most preferably 10% by mass or more.

Further, the fluorine atom content (% by mass) of the polymer can be determined by ¹³ C-NMR to determine the structure of the polymer.

<[D] Synthesis method of polymer containing fluorine atom>

The polymer of the [D] fluorine atom may be the same as the above [A] polymer, for example, by using a radical polymerization initiator to obtain a specific structural unit. The monomer is synthesized by polymerization in a suitable solvent.

<[E] Solvent>

The photoresist composition (I) usually contains an [E] solvent. The solvent of [E] is not particularly limited as long as it can dissolve at least the above-mentioned [A] polymer, [B] acid generator, and optionally any optional component.

The solvent of the [E] is, for example, at least one selected from the group consisting of an alcohol solvent, an ether solvent, a ketone organic solvent, a guanamine solvent, an ester organic solvent, and a hydrocarbon solvent.

The alcohol solvent is exemplified by, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, n-pentanol, isoamyl alcohol, 2-methylbutyl Alcohol, second pentanol, third pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, second hexanol, 2-ethylbutanol, second heptanol, 3-glycol Alcohol, n-octanol, 2-ethylhexanol, second octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n-nonanol, second-undecyl alcohol, trimethyl Sterol, second-tetradecyl alcohol, second heptadecyl alcohol, decyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, Monoalcoholic solvent such as diacetone alcohol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2 , a polyol solvent such as 5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol or tripropylene glycol; Glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, Ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, two Ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl A polyol partial ether such as ether or the like.

The ether solvent is exemplified by diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether, methoxybenzene, anisole (methylphenyl ether) and the like.

The ketone solvent is exemplified by, for example, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone (2-glycol). Ketone), ethyl n-butyl ketone, methyl n-hexyl ketone, diisobutyl ketone, trimethyl fluorenone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, A ketone solvent such as 2,4-pentanedione, etidylacetone or acetophenone.

The guanamine solvent is exemplified by, for example, N,N'-dimethylimidazolidinone, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, B. Indoleamine, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, and the like.

The ester solvent is exemplified by, for example, diethyl carbonate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, second butyl acetate, n-amyl acetate, Isoamyl acetate, second amyl acetate, 3-methoxybutyl acetate, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate , Methylcyclohexyl acetate, n-decyl acetate, methyl acetoxyacetate, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoacetate Methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl acetate Ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, diacetate glycol, methoxy tri-glycol acetate, ethyl propionate, n-butyl propionate, isoamyl propionate Ester, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate Ester and the like.

The hydrocarbon solvent is exemplified by, for example, n-pentane, isopentane, n-hexane, isohexane, n-heptane, isoheptane, 2,2,4-trimethylpentane, n-octane, isooctane, cyclohexane. An aliphatic hydrocarbon solvent such as an alkane or methylcyclohexane; benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, cumene, An aromatic hydrocarbon solvent such as diethylbenzene, isobutylbenzene, triethylbenzene, diisopropylbenzene or n-pentylnaphthalene.

Among these, an ester solvent, a ketone solvent, and an ether solvent are preferable, and an ester solvent and a ketone solvent are more preferable, and an ester solvent is more preferable. Specifically, the acetate or cyclic ketone of the polyol monoalkyl ether is preferably more preferably propylene glycol monoalkyl ether or cycloalkanone, more preferably propylene glycol monomethyl ether or cyclohexanone. Preferably, it is propylene glycol monomethyl ether. These [E] solvents may be used singly or in combination of two or more.

<Other optional ingredients>

The photoresist composition (I) may contain, in addition to the above components, other optional components such as a templating agent, a surfactant, a compound containing an alicyclic skeleton, and a sensitizer.

[biasing accelerator]

The biasing accelerator is a component which causes the polymer of the [D] fluorine atom to be more effectively segregated on the surface of the resist film. By allowing the photoresist composition (I) to contain a biasing accelerator, the polymer of the [D] fluorine atom can be more effectively segregated on the surface of the resist film, and as a result, the use of the [D] fluorine atom-containing polymer can be reduced. the amount. The above-mentioned partialization accelerator is exemplified by a lactone compound, a carbonate compound, a nitrile compound, a polyhydric alcohol, and the like. The above-mentioned partialization accelerator may be used alone or in combination of two or more.

The above lactone compound is exemplified by, for example, γ-butyrolactone, valerolactone, mevalononitrile, norbornane lactone and the like.

The above carbonate compound is exemplified by, for example, propyl carbonate, ethyl carbonate, butyl carbonate, and vinyl carbonate.

The above nitrile compound is exemplified by, for example, succinonitrile.

The above polyol is exemplified by glycerin or the like.

Among these, a lactone compound is preferred, and γ-butyrolactone is more preferred.

The content of the partialization accelerator is preferably from 5 parts by mass to 300 parts by mass, more preferably from 10 parts by mass to 100 parts by mass, even more preferably from 20 parts by mass to 70 parts by mass per 100 parts by mass of the [A] polymer. Parts by mass.

[Surfactant]

The surfactant is effective in improving coatability, streaking, and developing properties. As the surfactant, for example, polyoxyethylene ethyl lauryl ether, polyoxyethylene ethyl stearyl ether, polyoxyethylene ethyl oleyl ether, polyoxyethylene ethyl n-octyl phenyl ether, polyoxygen extension A nonionic surfactant such as ethyl n-nonylphenyl ether, polyethylene glycol dilaurate or polyethylene glycol distearate. Further, as a commercial item, KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), POLYFLOW No. 75, POLYFLOW No. 95 (manufactured by Kyoei Chemical Co., Ltd.), EF Top EF301, EF Top EF303, and EF Top EF352 (above) Manufactured by Tohchem Products, MEGAFAC F171, MEGAFAC F173 (above DIC), FLORARD FC430, FLORARD FC431 (above Sumitomo 3M), ASAHI GUARD AG710, SURFLON S-382, SURFLON SC-101, SURFLON SC- 102, SURFLON SC-103, SURFLON SC-104, SURFLON SC-105, SURFLON SC-106 (above is Asahi Glass). These surfactants may be used alone or in combination of two or more.

[A compound containing an alicyclic skeleton]

The compound containing an alicyclic skeleton exhibits effects of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

The compound having an alicyclic skeleton is exemplified by adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid tert-butyl ester; tert-butyl deoxycholate; Deoxycholate such as tributoxycarbonyl methyl deoxycholate or 2-ethoxyethyl deoxycholate; tert-butyl lithochate, tert-butoxycarbonyl methyl lithate, stone a cholinate such as 2-ethoxyethyl cholate; 3-[2-hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1 ^2,5 .1 ^{7, 10} ] Dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0 ^3,7 ]decane, and the like. These alicyclic skeleton-containing compounds may be used alone or in combination of two or more.

[sensitizer]

The sensitizer exhibits an effect of increasing the amount of formation of the [B] acid generator, and exhibits an effect of improving the "apparent sensitivity" of the photoresist composition (I).

The sensitizers are exemplified by, for example, carbazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetyl oximes, eosin, rose red, pyrenes, hydrazines. Classes, phenothiazines, etc. These sensitizers may be used alone or in combination of two or more.

<Modulation method of photoresist composition>

The photoresist composition (I) can be prepared, for example, by mixing the [A] polymer, the [B] acid generator, the optional component, and the [E] solvent in a specific ratio. The photoresist composition (I) is usually prepared by mixing the respective components so that the total solid content concentration is 1 to 50% by mass, preferably 3 to 25% by mass, and then filtering by a filter having a pore diameter of about 0.2 μm or the like.

[Examples]

The present invention will be more specifically described below based on the examples, but the present invention is not limited by the examples. Further, the method for measuring the properties of each substance is shown below.

[Mw and Mn]

The Mw and Mn of the polymer were measured by a gel permeation chromatography (GPC) under the following conditions. Further, the degree of dispersion (Mw/Mn) was calculated from the measurement results of Mw and Mn.

Pipe string: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (made by TOSOH)

Dissolution: tetrahydrofuran

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Column temperature: 40 ° C

Detector: differential refractometer

Reference material: monodisperse polystyrene

[Low molecular weight component content]

The content (% by mass) of the low molecular weight component (component having a molecular weight of less than 1,000) in the polymer was measured by a high-speed liquid chromatography (HPLC) under the following conditions.

Column: Intersil ODS-25μm column (4.6mm ×250mm) (made by JL Science)

Dissolution solvent: acrylonitrile / 0.1% by mass phosphoric acid aqueous solution

Flow rate: 1.0mL/min

Sample concentration: 1.0% by mass

Sample injection amount: 100 μL

Detector: differential refractometer

[ ¹³ C-NMR analysis]

The ¹³ C-NMR analysis for determining the content ratio of each constituent unit of the polymer was measured using a nuclear magnetic resonance apparatus ("JNM-ECX400" manufactured by JEOL Ltd.).

<Synthesis of Polymers>

The monomers used in the synthesis of the [A] polymer and the [D] fluorine atom-containing polymer are shown below.

The above compound (M-1) and the compound (M-14) are obtained by obtaining the structural unit (I) in the [A] polymer, and the compounds (M-2) to (M-12) and the compound (M-15) are obtained. Construction unit (II).

<[A] Synthesis of Polymers>

[Synthesis Example 1]

13.58 g (50 mol%) of the compound (M-1) and 6.42 g (50 mol%) of the compound (M-2) were dissolved in 40 g of 2-butanone, followed by use as a radical polymerization initiator. AIBN 1.22 g (5 mol% based on the total mole of the compound) was dissolved to prepare a monomer solution. After injecting 20 g of 2-butanone into a 100 mL three-necked flask under nitrogen for 30 minutes, the mixture was heated to 80 ° C with stirring, and the above-prepared monomer solution was added dropwise over 3 hours with a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. After completion of the polymerization reaction, the polymerization reaction liquid was cooled to 30 ° C or lower by water cooling. The cooled polymerization reaction liquid was poured into 400 g of methanol, and the precipitated white powder was filtered. The filtered white powder was washed twice with 80 g of methanol, and then filtered and dried at 50 ° C for 17 hours to obtain a white powdery polymer (A-1) (15.4 g, yield 77%). The polymer (A-1) had Mw of 7,000 and Mw/Mn of 1.53. As a result of ¹³ C-NMR analysis, the content ratio of the compound (M-1) and the compound (M-2) was 50.5 mol% and 49.5 mol%, respectively. Further, the content of the low molecular weight component in the polymer (A-1) was 0.05% by mass.

[Synthesis Example 2~17]

Each of the polymers was synthesized in the same manner as in Synthesis Example 1 except that the monomers of the type and amount used in Table 1 were used. The total mass of the monomers used was set to 20 g. The yield (%), Mw and Mw/Mn of each of the synthesized polymers are shown in Table 1. The "-" in Table 1 indicates that the monomer is not used.

<[D] Synthesis of a fluorine atom-containing polymer>

[Synthesis Example 18]

Compound (M-1) 79.9 g (70 mol%) and compound (M-13) 20.91 g (30 mol%) were dissolved in 100 g of 2-butanone, followed by 2 as a radical polymerization initiator 2.77 g of 2'-azobisisobutyric acid dimethyl ester was dissolved to prepare a monomer solution. The 1,000-mL three-necked flask in which 100 g of 2-butanone was injected was blown with nitrogen for 30 minutes, and then heated to 80 ° C with stirring, and the above-prepared monomer solution was added dropwise over 3 hours with a dropping funnel. The polymerization reaction was carried out for 6 hours starting from the start of the dropwise addition as the start time of the polymerization reaction. After completion of the polymerization reaction, the polymerization reaction liquid was cooled to 30 ° C or lower by water cooling. After the reaction solution was pipetted into a 2 L separatory funnel, the polymerization reaction solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added thereto and mixed. Next, 30 g of distilled water was charged, and the mixture was further stirred and allowed to stand for 30 minutes. Subsequently, the lower layer was recovered to prepare a propylene glycol monomethyl ether acetate solution of the polymer (D-1) (yield 60%). The obtained polymer (D-1) had Mw of 7,200, Mw/Mn of 2.00, and a low molecular weight component content of 0.07% by mass. As a result of ¹³ C-NMR analysis, the content ratio of the compound (M-1) and the compound (M-13) in the polymer (D-1) was 71.1 mol% and 28.9 mol%.

<Modulation of Photoresist Composition>

The [B] acid generator, [C] acid diffusion control agent, [E] solvent, and [F] biasing accelerator used in the preparation of the photoresist composition are shown below.

([B]acid generator)

B-1: triphenylsulfonium 2-(1-adamantyl)-1,1-difluoroethanesulfonate (compound represented by the following formula (B-1))

B-2: 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiophene hexafluoropropyl sulfonimide (a compound represented by the following formula (B-2))

B-3: triphenylsulfonium 2-(adamantan-1-ylcarbonyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonate (with the following formula (B-3) Compound represented)

([C] acid diffusion control agent)

C-1: triphenylsulfonium 10-camphorsulfonate (compound represented by the following formula (C-1))

([E] solvent)

E-1: propylene glycol monomethyl ether

E-2: cyclohexanone

([F] partialization accelerator)

F-1: γ-butyrolactone

[Example 1]

100 parts by mass of (A-1) as the [A] polymer, (B-1) 8.5 parts by mass as the [B] acid generator, and (C-1) 30% as the [C] acid diffusion controlling agent Ear % (relative to the molar ratio of the [B] acid generator), (D-1) 3 parts by mass of the polymer as the [D] fluorine atom, (E-1) 2,240 mass as the [E] solvent And (E-2) 960 parts by mass, and 30 parts by mass of (F-1) as the [F] biasing accelerator, the photoresist composition (J-1) was prepared.

[Examples 2 to 15 and Comparative Examples 1 and 2]

The photoresist compositions (J-2) to (J-15) and (CJ-1) and (CJ-) were prepared in the same manner as in Example 1 except that the components of the types and the amounts shown in Table 2 below were used. 2).

<Formation of photoresist pattern>

[Example 16]

The composition for forming an underlying antireflection film (ARC66, manufactured by Brewer Science) was applied onto a 12-inch wafer surface by a spin coater (CLEAN TRACK ACT12, manufactured by Tokyo Electronics Co., Ltd.), and then heated at 205 ° C for 60 seconds. A layer anti-reflection film having a film thickness of 105 nm was formed. The photoresist composition (J-1) was applied onto the underlying antireflection film using the above spin coater, and PB was carried out at 90 ° C for 60 seconds. Subsequently, it was cooled at 23 ° C for 30 seconds to form a resist film having a film thickness of 90 nm. Next, using an ArF excimer laser immersion exposure apparatus (NSR-S610C, manufactured by NIKON), with a line condition of NA = 1.30, dipole (σ 0.977/0.782), a line and a spacer (1L1S) masked at 40 nm. The pattern is exposed. After exposure, PEB was carried out at 90 ° C for 60 seconds. Subsequently, n-butyl acetate was used as a developing solution for development, and dried to form a negative resist pattern. Further, in the formation of the resist pattern, the exposure amount of the line width of 40 nm and the interval pattern (1L1S) formed as a line width of 1 to 1 is used as the optimum exposure amount (Eop).

[Examples 17 to 30 and Comparative Examples 3 and 4]

Except that the photoresist compositions (J-2) to (J-15) and (CJ-1) and (CJ-2) were used instead of the photoresist composition (J-1), respectively, the same as in Example 16, Each photoresist pattern is formed.

<Evaluation>

Each of the photoresist compositions was evaluated based on the measurement of each of the resist patterns formed as described above. The evaluation results are shown together in Table 2. The measurement of the resist pattern was performed using a scanning electron microscope (S-9380, manufactured by Hitachi High-Tech).

[LWR performance]

Using the above scanning electron microscope, the resist pattern formed by the above Eop was observed from the upper portion of the pattern. A line width of 50 points in total was measured at an arbitrary point, and a value of 3σ was obtained from the distribution of the measured values as LWR performance (nm). The smaller the value, the better the LWR performance. Compared with the comparative example 1, the LWR performance can be evaluated as "good" when the LWR performance is increased by 10% or more (the value of the LWR is 90% or less), and the "lower" when the LWR performance is less than 10%. "."

[resolution]

The size of the minimum resist pattern of the solution in the above Eop is taken as the resolution (nm). The smaller the value, the better the resolution. Compared with the comparative example 1, when the resolution is improved by 10% or more (the value of the resolution is 90% or less), it can be evaluated as "good", and when the resolution is less than 10%, the resolution is improved. Can be evaluated as "bad".

[Rectangularity of section shape]

The cross-sectional shape of the resist pattern of the solution in the above Eop was observed, and the line width Lb in the middle of the height direction of the resist pattern and the line width La in the upper portion of the pattern were measured. The value of La/Lb was calculated from these measured values as an index of the squareness of the cross-sectional shape. The closer to 1 is, the better the squareness of the cross-sectional shape is. The rectangular shape of the cross-sectional shape in the resist pattern is 0.9 ≦ (La/Lb) ≦ 1.1, which can be evaluated as “good”, and (La/Lb) ≦ 0.9 or 1.1 ≦ (La/Lb) can be evaluated as “bad”. "."

It can be understood from the results of Table 2 that the negative resist pattern formation method and the photoresist composition according to the examples do not use a lactone structure or a sulfonate in the formation of a negative pattern using a developing solution containing an organic solvent. The lactone structure can form a negative resist pattern having excellent RWR properties, resolution, and cross-sectional shape.

[Industrial availability]

According to the negative resist pattern forming method and the photoresist composition of the present invention, in the pattern formation using a developing solution containing an organic solvent, a monomer having a lactone structure or a sultone structure can be used. A negative resist pattern having a small LWR, high resolution, and excellent squareness in cross-sectional shape is formed. Accordingly, these can be preferably used for pattern formation in the field of semiconductor fabrication which is more refined.

Claims (5)

A negative resist pattern forming method having the steps of: using a photoresist composition to form a resist film; exposing the resist film; and using a developing solution containing an organic solvent to cause the above a step of developing an exposed resist film, wherein the photoresist composition contains a structural unit (I) represented by the following formula (1) and a formula (2-1) and a formula (2-2) a polymer of at least one structural unit (II) selected from the group consisting of structural units represented by the formula (2-3), and an acid generator, the structural unit (I) and the structural unit (II) in the above polymer The total ratio is 90% or more, (In the formula (I), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ² is a monovalent acid dissociable group), (In the formula (2-1), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁴ is a single bond, *-C(=O)-O- or *-C(=O) -NH-, however, * represents a bonding site with a carbon atom to which R ³ is bonded, and R ⁵ is a single bond, a methylene group or an alkylene group having a carbon number of 2 to 5, and R ⁶ is a ring member number 5~ a monovalent aliphatic heterocyclic group of 20, a monovalent chain hydrocarbon group having 1 to 5 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a hydrogen atom, and the above aliphatic heterocyclic group is contained between carbon and carbon From -OC(=O)-O-, -SC(=S)-O-, -C(=O)-N(-* *)-C(=O)-, -O-, and -S- At least one selected from the group consisting of at least one hydrogen atom selected from the group consisting of ^a hydroxyl group, a cyano group, ^a nitro group, a -NHSO ₂ R ^a group and an oxo group, and at least one selected from the group consisting of a chain hydrocarbon group and an alicyclic hydrocarbon group Substituted by one group, R ^a is an alkyl group having 1 to 5 carbon atoms which may be substituted by a fluorine atom, * * represents a bonding site with R ⁵ , and in the formula (2-2), R ⁷ and R ^{8 are} each independently R ⁹ to R ^{12 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but two or more of R ⁹ to R ¹² may be bonded to each other to form a hydrogen atom, a fluorine atom or a methyl group. The carbon number of the carbon atom to be bonded is 3 to 10 ring structure, m1 and m2 are independent Is an integer of 0 to 2, each R ⁹ ~ R ¹² is plural, plural R ⁹ ~ R ¹² may be the same or different, R ¹³ is -O- or -NR ^A -, R ^A is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a hydrogen atom of a part of the alkyl group, a cycloalkyl group and an aryl group substituted by a hydroxyl group or a carboxyl group In the formula (2-3), R ¹⁴ is a hydrogen atom or a methyl group, and R ¹⁵ to R ^{18 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but 2 of R ¹⁵ to R ¹⁸ One or more of them may be bonded to each other to form a ring structure having carbon atoms of 3 to 10 which are bonded to the carbon atoms to be bonded, and n1 and n2 are each independently an integer of 0 to 2, and when R ¹⁵ to R ¹⁸ are plural, respectively. A plurality of R ¹⁵ to R ¹⁸ may be the same or different, R ¹⁹ is -O- or -NR ^B -, and R ^B is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, and a ring having 4 to 20 carbon atoms. An alkyl group, an aryl group having 6 to 20 carbon atoms, or a group in which a part of hydrogen atoms of the alkyl group, the cycloalkyl group and the aryl group are substituted by a hydroxyl group or a carboxyl group). The negative resist pattern pattern forming method of claim 1, wherein the R ² in the above formula (1) is represented by the following formula (i), (In the formula (i), R ^p1 is a monovalent chain hydrocarbon group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, and R ^p2 and R ^{p3 are} each independently 1 to 4 carbon atoms. A valence chain hydrocarbon group or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a combination of R ^p2 and R ^p3 bonded to the carbon atoms bonded thereto to form an alicyclic structure having a ring carbon number of 4 to 20). The method for forming a negative resist pattern according to claim 2, wherein R ^p2 and R ^p3 in the above formula (i) are bonded to each other to form an alicyclic ring having a ring carbon number of 4 to 12 together with the bonded carbon atoms. structure. The method for forming a negative resist pattern according to claim 1, wherein the content ratio of the structural unit (I) in the polymer is 20 mol% or more and 90 mol The ear content is less than or equal to the ear, and the content ratio of the structural unit (II) is 10 mol% or more and 80 mol% or less. A photoresist composition for forming a negative pattern of a developing solution containing an organic solvent, which comprises a structural unit (I) represented by the following formula (1) and a polymer of at least one structural unit (II) selected from the group consisting of structural units represented by the formula (2-1), the formula (2-2), and the formula (2-3), and an acid generator in the above polymer The total content of the structural unit (I) and the structural unit (II) is 90 mol% or more. (In the formula (I), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ² is a monovalent acid dissociable group), (In the formula (2-1), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, and R ⁴ is a single bond, *-C(=O)-O- or *-C(=O) -NH-, however, * represents a bonding site with a carbon atom to which R ³ is bonded, and R ⁵ is a single bond, a methylene group or an alkylene group having a carbon number of 2 to 5, and R ⁶ is a ring member number 5~ a monovalent aliphatic heterocyclic group of 20, a monovalent chain hydrocarbon group having 1 to 5 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a hydrogen atom, and the above aliphatic heterocyclic group is contained between carbon and carbon From -OC(=O)-O-, -SC(=S)-O-, -C(=O)-N(-* *)-C(=O)-, -O-, and -S- At least one selected from the group consisting of at least one hydrogen atom selected from the group consisting of ^a hydroxyl group, a cyano group, ^a nitro group, a -NHSO ₂ R ^a group and an oxo group, and at least one selected from the group consisting of a chain hydrocarbon group and an alicyclic hydrocarbon group Substituted by one group, R ^a is an alkyl group having 1 to 5 carbon atoms which may be substituted by a fluorine atom, * * represents a bonding site with R ⁵ , and in the formula (2-2), R ⁷ and R ^{8 are} each independently R ⁹ to R ^{12 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but two or more of R ⁹ to R ¹² may be bonded to each other to form a hydrogen atom, a fluorine atom or a methyl group. The carbon number of the carbon atom to be bonded is 3 to 10 ring structure, m1 and m2 are independent Is an integer of 0 to 2, each R ⁹ ~ R ¹² is plural, plural R ⁹ ~ R ¹² may be the same or different, R ¹³ is -O- or -NR ^A -, R ^A is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 4 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a hydrogen atom of a part of the alkyl group, a cycloalkyl group and an aryl group substituted by a hydroxyl group or a carboxyl group In the formula (2-3), R ¹⁴ is a hydrogen atom or a methyl group, and R ¹⁵ to R ^{18 are} each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, but 2 of R ¹⁵ to R ¹⁸ One or more may be bonded to each other to form a ring structure having carbon atoms of 3 to 10 which are bonded to the carbon atoms, and n1 and n2 are each an integer of 0 to 2, and when R ¹⁵ to R ¹⁸ are plural, respectively. A plurality of R ¹⁵ to R ¹⁸ may be the same or different, R ¹⁹ is -O- or -NR ^B -, and R ^B is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, and a ring having 4 to 20 carbon atoms. An alkyl group, an aryl group having 6 to 20 carbon atoms, or a group in which a part of hydrogen atoms of the alkyl group, the cycloalkyl group and the aryl group are substituted by a hydroxyl group or a carboxyl group).