JP2012203406A - Radiation-sensitive resin composition for liquid immersion exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition for liquid immersion exposure which is capable of providing a resist coating film that exhibits excellent drainability on the surface by having a high dynamic contact angle during the exposure in a liquid immersion exposure process, while suppressing occurrence of development defects by being greatly decreased in the dynamic contact angle during the development.SOLUTION: The radiation-sensitive resin composition for liquid immersion exposure contains: [A] a polymer having a fluorine atom, an alkali-dissociable group, and an alicyclic group in the main chain; and [C] an acid generator. [A] The polymer preferably contains a structural unit (I) represented by formula (1).

Description

  The present invention relates to a radiation-sensitive resin composition for immersion exposure.

  In the field of microfabrication represented by the manufacture of integrated circuit elements, conventionally, a resist film is formed on a substrate with a resin composition containing a polymer having an acid-dissociable group, and the resist film is formed on the resist film via a mask pattern. A fine resist pattern is formed by irradiating a short-wavelength radiation such as an excimer laser for exposure, and removing an exposed portion with an alkaline developer.

  In recent years, the use of the immersion exposure method is expanding as a method for forming a finer resist pattern having a line width of about 45 nm. The immersion exposure method has an advantage that the depth of focus is hardly lowered even when the numerical aperture (NA) of the lens is increased, and high resolution can be obtained. The resin composition used in the immersion exposure method suppresses elution of the acid generator and the like from the formed resist film to the immersion medium, and prevents deterioration of the coating film performance and contamination of the lens, etc. It is required to improve the water drainage of the resist film surface to prevent the watermark from remaining and to enable high-speed scan exposure.

  As means for achieving these, for example, Japanese Patent Application Laid-Open No. 2005-352384 proposes a technique for forming an upper layer film (protective film) on a resist film, but requires a separate film formation step, which is complicated. . Therefore, methods for increasing the hydrophobicity of the resist film surface have been studied. For example, International Publication No. 2007/116664 proposes a resin composition containing a fluorine-containing polymer having high hydrophobicity.

  However, if the hydrophobicity of the resist film is increased, the surface wettability of the developing solution and the rinsing solution decreases, so that the development residue deposited on the unexposed portion of the resist surface during development becomes insufficient, and blob (Blob) etc. Development defects may occur. For the purpose of suppressing such development defects, JP 2010-032994 A proposes a fluorine-containing polymer that is hydrophobic during immersion exposure but decreases in hydrophobicity during alkali development. .

  In these documents, the change in hydrophobicity of the resist film is confirmed using the static contact angle with water as an index.

JP 2005-352384 A International Publication No. 2007/116664 JP 2010-032994 A

  However, the dynamic contact angle such as the receding contact angle is more important than the static contact angle as an index regarding the above-mentioned water drainage performance in the actual immersion exposure process. In addition, in order to shorten the development process time, it is also desired that such a change in the dynamic contact angle occurs in a shorter time during the processing of the developer. In that respect, the degree of decrease in the dynamic contact angle after alkali development of the fluorine-containing polymer shown in the above document and the time required for the contact angle change do not sufficiently contribute to the improvement in the actual immersion exposure process. .

  The present invention has been made based on the circumstances as described above, and its purpose is to exhibit excellent water drainage on the resist film surface by showing a large dynamic contact angle during exposure in the immersion exposure process. A radiation-sensitive resin composition for immersion exposure that gives a resist film in which the occurrence of development defects is suppressed by greatly reducing the dynamic contact angle during development, and further reduces the time required for changing the dynamic contact angle. Is to provide.

The invention made to solve the above problems is
[A] a polymer having a fluorine atom and an alkali dissociable group and having an alicyclic group in the main chain (hereinafter also referred to as “[A] polymer”), and a liquid containing [C] an acid generator A radiation-sensitive resin composition for immersion exposure.

  The [A] polymer contained in the composition is a polymer having a fluorine atom and an alicyclic group in the main chain. [A] The polymer has an alicyclic group in the main chain in addition to having a fluorine atom, so that an upper layer film for the purpose of blocking the resist film and the immersion medium can be separately formed. Without necessity, the resist film surface exhibits a larger dynamic contact angle. Therefore, according to the composition, elution of the [C] acid generator and the like from the resist film can be suppressed, and higher drainage characteristics can be imparted to the resist film surface. Furthermore, since the [A] polymer has a fluorine atom, in alkali development, the alkali dissociable group of the [A] polymer is more easily dissociated to produce a hydrophilic group, and the resist film surface The hydrophobicity of is greatly reduced. As a result, the dynamic contact angle during the development in the alkaline development process is greatly reduced, so that the wettability of the resist film surface to the developer and the rinse liquid is greatly improved. Occurrence of development defects in the film can be further suppressed.

[A] The polymer preferably contains a structural unit (I) represented by the following formula (1).

(In Formula (1), R < ¹ > -R < ⁴ > is respectively independently a hydrogen atom, a fluorine atom, or a C1-C20 monovalent organic group. A is 0 or 1. b is It is an integer from 0 to 2.)

  By including the structural unit (I) as the main structural unit of the [A] polymer, the [A] polymer can have a bulkier alicyclic group, and uneven distribution is further promoted.

At least one of R ^{1 to} R ⁴ is preferably a fluorine atom or a trifluoromethyl group. As an embodiment in which the [A] polymer has a fluorine atom, the [A] polymer can be more unevenly distributed by having a fluorine atom in the structural unit (I).

（式（２）中、Ｒ^５はアルカリ解離性基である。） At least one of the R ^{1 to} R ⁴ is preferably a group represented by the following formula (2).

(In formula (2), R ⁵ is an alkali dissociable group.)

  [A] As an aspect in which the polymer has an alkali-dissociable group, having an alkali-dissociable group in the structural unit (I) promotes uneven distribution and further increases the decrease in dynamic contact angle. Can do.

R ⁵ is a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or a carbon number having 6 to 20 which may be substituted with a fluorine atom or a fluorinated alkyl group. It is preferable that it is an aromatic group. The R ⁵ is an alkali dissociative group, the effect of the more the present invention by the above specific groups is improved.

（式（３）中、Ｒ^６及びＲ^７は、それぞれ独立して炭素数１〜２０の１価の有機基である。Ｒ^８及びＲ^９は、それぞれ独立して２価の連結基である。） [A] The polymer may further contain a structural unit (II) represented by the following formula (3), and at least one of the above R ⁸ and R ⁹ is an oxygen atom, and R is bonded to this oxygen atom. ⁶ or R ⁷ is preferably an alkali dissociable group.

(In Formula (3), R ⁶ and R ⁷ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a divalent linking group. .)

  [A] As an aspect in which the polymer has an alkali-dissociable group, an aspect further including the structural unit (II) is preferable, and since the structural unit has an alkali-dissociable group, the density of the alkali-dissociable group is present. The effect of the present invention is further improved.

It is preferable that the alkali dissociable group represented by R ⁶ or R ⁷ bonded to the oxygen atom is a linear or branched fluorinated alkyl group having 1 to 10 carbon atoms. When the structural unit (II) has a fluorine atom, the alkali-dissociable group is more easily dissociated in the alkali development step to generate a hydrophilic group, and the hydrophobicity of the resist film surface is further reduced.

  [A] The polymer preferably further includes a structural unit (III) having —C (═O) —O—C (═O) —, and the structural unit (III) is derived from maleic anhydride. More preferably, it is a structural unit. By including the structural unit (III) in the [A] polymer, for example, in addition to the structural unit (I), the [A] polymer can have a bulky structure in the main chain. Further, in the alkali development step, the structural unit (III) derived from maleic anhydride is easily dissociated by hydrolysis, so that the dynamic contact angle can be reduced in a shorter time.

  The composition further contains a base polymer having a [B] acid dissociable group and having a fluorine atom content smaller than that of the [A] polymer (hereinafter also referred to as “[B] polymer”). Is preferred. When the composition contains the [B] polymer, uneven distribution of the [A] polymer component is further promoted. As a result, the resist film surface exhibits a larger dynamic contact angle without the need to separately form an upper layer film for the purpose of blocking the resist film and the immersion medium.

  The composition preferably further contains a [D] acid diffusion controller. The composition further contains a [D] acid diffusion control agent, thereby controlling the diffusion phenomenon of the acid generated from the [C] acid generator upon exposure in the resist film and suppressing undesirable chemical reactions in the non-exposed areas. As a result, the storage stability of the resulting radiation-sensitive resin composition is improved, the resolution of the resist is improved, and the change of the resist pattern line width due to fluctuations in the holding time from exposure to development processing is achieved. The composition which can be suppressed and is extremely excellent in process stability is obtained.

  As described above, the radiation-sensitive resin composition for immersion exposure of the present invention is such that the resist film formed in the immersion exposure process exhibits a moderately large dynamic contact angle during exposure, while after alkali development. The dynamic contact angle is greatly reduced, and the time required for changing the dynamic contact angle can be shortened. As a result, in addition to suppressing the elution of acid generators from the resist film, the resist film surface has excellent water drainage, enabling high-speed scan exposure and compatibility with the developer during development. Therefore, the occurrence of development defects can be suppressed and a good resist pattern can be formed.

<Radiation-sensitive resin composition for immersion exposure>
The radiation-sensitive resin composition for immersion exposure of the present invention contains a [A] polymer and a [C] acid generator. Moreover, the said composition can contain a [B] polymer and a [D] acid diffusion control agent as a suitable component. Furthermore, the said composition may contain another arbitrary component, unless the effect of this invention is impaired. Hereinafter, each component will be described in detail.

<[A] polymer>
[A] The polymer is a polymer having a fluorine atom and an alkali-dissociable group and having an alicyclic group in the main chain.

[Structural unit (I)]
[A] The polymer is not particularly limited as long as it has a fluorine atom and an alkali dissociable group and an alicyclic group in the main chain, but the structural unit represented by the above formula (1) (I ) As a main structural unit of the polymer [A]. By including the structural unit (I) as the main structural unit of the [A] polymer, the [A] polymer can have a bulkier alicyclic group, and uneven distribution is further promoted.

In said formula (1), R < ¹ > -R < ⁴ > is a hydrogen atom, a fluorine atom, or a C1-C20 monovalent organic group each independently. a is 0 or 1. b is an integer of 0-2.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^{1 to} R ⁴ include a chain or branched hydrocarbon group having 1 to 20 carbon atoms and an alicyclic group having 3 to 20 carbon atoms. Examples thereof include a hydrocarbon group or an aromatic hydrocarbon group having 6 to 20 carbon atoms. However, one part or all part of the hydrogen atom which these groups have may be substituted.

Examples of the chain or branched hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, a methylcyclohexyl group, and an ethylcyclohexyl group. Monocyclic saturated hydrocarbon group; such as cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group, cyclodecenyl group, cyclopentadienyl group, cyclohexadienyl group, cyclooctadienyl group, cyclodecadiene, etc. Monocyclic unsaturated hydrocarbon group; bicyclo [2.2.1] heptyl group, bicyclo [2.2.2] octyl group, tricyclo [5.2.1.0 ^2,6 ] decyl group, tricyclo [3 .3.1.1 ^3,7] decyl group, tetracyclo [6.2.1.1 ^, 6. 0 ^2,7 ] dodecyl group, polycyclic saturated hydrocarbon group such as adamantyl group and the like. As said C6-C20 aromatic hydrocarbon group, a phenyl group, a biphenyl group, a terphenyl group, a benzyl group, a naphthyl group etc. are mentioned, for example.

At least one of R ^{1 to} R ⁴ is preferably a fluorine atom or a trifluoromethyl group. As an embodiment in which the [A] polymer has a fluorine atom, the [A] polymer can be more unevenly distributed by having a fluorine atom in the structural unit (I). Moreover, it is preferable that at least 1 of said R < ¹ > -R < ⁴ > is group represented by the said Formula (2). [A] As an aspect in which the polymer has an alkali-dissociable group, having an alkali-dissociable group in the structural unit (I) promotes uneven distribution and further increases the decrease in dynamic contact angle. Can do.

In the above formula (2), R ⁵ is an alkali dissociable group. The alkali-dissociable group is a group that replaces a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group, and is in the presence of an alkali (for example, 2.38% by mass of tetramethylammonium hydroxyside at 23 ° C. A group that dissociates in an aqueous solution. Thereby, a structural unit (I) will produce a polar group by the effect | action of an alkali.

R ⁵ is a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or a carbon number having 6 to 20 which may be substituted with a fluorine atom or a fluorinated alkyl group. It is preferable that it is an aromatic group. The R ⁵ is an alkali dissociative group, the effect of the more the present invention by the above specific groups is improved.

  As a and b, 0 is preferable. As the structural unit (I), a structural unit represented by the following formula is preferred.

  [A] The polymer may contain two or more structural units (I). [A] The content of the structural unit (I) with respect to all the structural units in the polymer is preferably 30 mol% or more and 100 mol% or less. By setting the content of the structural unit (I) in the specific range, it is possible to achieve a sufficient decrease in the dynamic contact angle due to development as well as a large dynamic contact angle during immersion exposure.

[Structural unit (II)]
[A] The polymer may further contain the structural unit (II) represented by the above formula (3). In the above formula (3), R ⁶ and R ⁷ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a divalent linking group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the R ⁶ and R ⁷ include the groups exemplified as the monovalent organic group having 1 to 20 carbon atoms represented by the R ^{1 to} R ^4. Is applicable.

Examples of the divalent linking group represented by R ⁸ and R ⁹ include a divalent chain hydrocarbon group having 1 to 30 carbon atoms, a divalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms, Examples thereof include a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, an ether group, an ester group, a carbonyl group, an imino group, an amide group, or a divalent group obtained by combining these.

  Examples of the divalent chain hydrocarbon group having 1 to 30 carbon atoms include a methanediyl group, an ethanediyl group, a propanediyl group, a butanediyl group, a pentanediyl group, a hexanediyl group, an octanediyl group, a decandidiyl group, and an undecandiyl group. Alkenediyl groups such as ethenediyl group, propenediyl group, butenediyl group, pentenediyl group, hexenediyl group, octenediyl group, decenediyl group, undecenediyl group, hexadecenediyl group, icocenediyl group; And alkynediyl groups such as propynediyl group, butynediyl group, octynediyl group, butadienediyl group, hexadienediyl group, octatrienediyl group and the like.

Examples of the divalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms include cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, cyclooctanediyl group, cyclohexane Monocyclic saturated hydrocarbon groups such as decanediyl group, methylcyclohexanediyl group, ethylcyclohexanediyl group; cyclobutenediyl group, cyclopentenediyl group, cyclohexenediyl group, cycloheptenediyl group, cyclooctenediyl group, cyclodecenediyl group Group, cyclopentadienediyl group, cyclohexadienediyl group, cyclooctadienediyl group, cyclodecadienediyl group and the like; bicyclo [2.2.1] heptanediyl group, bicyclo [2.2 .2] Octanediyl group Tricyclo [5.2.1.0 ^{2, 6]} decanediyl group, tricyclo [3.3.1.1 ^{3, 7]} decanediyl group, tetracyclo [6.2.1.1 ^{3, 6.} 0 ^2,7 ] polycyclic saturated hydrocarbon groups such as dodecanediyl group and adamantanediyl group; bicyclo [2.2.1] heptenediyl group, bicyclo [2.2.2] octenediyl group, tricyclo [5.2.1] .0 ^2,6] Desenjiiru group, tricyclo [3.3.1.1 ^{3, 7]} Desenjiiru group, tetracyclo [6.2.1.1 ^{3, 6.} And a polycyclic unsaturated hydrocarbon group such as 0 ^2,7 ] dodecenediyl group. Examples of the divalent aromatic hydrocarbon group having 6 to 30 carbon atoms include a phenylene group, a biphenylene group, a terphenylene group, a benzylene group, a phenyleneethylene group, a phenylenecyclohexylene group, and a naphthylene group.

As the structural unit (II), it is preferable that at least one of R ⁸ and R ⁹ is an oxygen atom, and R ⁶ or R ⁷ bonded to the oxygen atom is an alkali dissociable group. By having the alkali dissociable group in the structural unit (II), the density of the alkali dissociable group is increased, and the effect of the present invention is further improved.

R ⁶ and R ⁷ are preferably each independently a linear or branched fluorinated alkyl group having 1 to 10 carbon atoms. When the structural unit (II) has a fluorine atom, the alkali-dissociable group is more easily dissociated in the alkali development step to generate a hydrophilic group, and the hydrophobicity of the resist film surface is further reduced.

  Examples of the alkyl group of the fluorinated alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, and a t-butyl group. Is mentioned.

  As the structural unit (II), a structural unit represented by the following formula is preferred.

  [A] The polymer may contain two or more structural units (II). [A] As a content rate of structural unit (II) with respect to all the structural units in a polymer, 30 mol% or more and 60 mol% or less are preferable. By setting the content of the structural unit (II) within the above specific range, it is possible to achieve a sufficient decrease in the dynamic contact angle by development as well as a large dynamic contact angle during immersion exposure.

[Structural unit (III)]
[A] The polymer preferably further includes a structural unit (III) having —C (═O) —O—C (═O) —. By including the structural unit (III) in the [A] polymer, for example, in addition to the structural unit (I), the [A] polymer can have a bulky structure in the main chain. Further, in the alkali development step, the structural unit (III) having —C (═O) —O—C (═O) — is easily dissociated by hydrolysis, so that the decrease in the dynamic contact angle is further shortened. Can be realized in time.

  The structural unit (III) is preferably a structural unit derived from maleic anhydride, and examples thereof include a structural unit represented by the following formula.

In the above formula, R ¹⁰ is a monovalent organic group having 1 to 20 carbon atoms. c is an integer of 0-2. However, when R ¹⁰ is plural, the plurality of R ¹⁰ may be different even in the same.

As the monovalent organic group having 1 to 20 carbon atoms represented by R ¹⁰ , for example, the groups exemplified as the monovalent organic group having 1 to 20 carbon atoms represented by R ^{1 to} R ⁴ can be applied. .

  [A] The polymer may contain two or more kinds of structural units (III). [A] As a content rate of structural unit (III) with respect to all the structural units in a polymer, 30 mol% or more and 60 mol% or less are preferable. By making the content rate of structural unit (III) into the said specific range, sufficient fall of the dynamic contact angle by image development can be achieved with the large dynamic contact angle at the time of immersion exposure.

  As content of the [A] polymer in the said composition, when it contains the [B] polymer mentioned later, 0.1 mass part or more and 10 mass parts or less are with respect to 100 mass parts of [B] polymers. preferable. [A] By making the content of the polymer within the above specified range, segregation of the polymer [A] on the surface of the resist film occurs effectively, so that elution from the resist film is further suppressed and the resist Since the dynamic contact angle on the film surface is further increased, the water drainage can be further improved.

<[A] Polymer Synthesis Method>
[A] As a method for synthesizing the polymer, for example, a monomer corresponding to each predetermined structural unit can be produced by polymerizing in a suitable solvent using a radical polymerization initiator. For example, a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; a solution containing a monomer and a solution containing a radical initiator Respectively, a method of dropping a solution into a reaction solvent or a monomer-containing solution to cause a polymerization reaction; a plurality of types of solutions each containing a monomer, and a solution containing a radical initiator, It is preferable to synthesize by a method such as a method of dropping it into a reaction solvent or a solution containing a monomer to cause a polymerization reaction.

  Examples of the monomer that gives the structural unit (I) include monomers represented by the following formulas.

In said formula, R < ¹ > -R < ⁴ >, a and b are synonymous with the said Formula (1).

  As a monomer which gives structural unit (II), the monomer etc. which are represented by a following formula are mentioned, for example.

In said formula, R < ⁶ > -R < ⁹ > is synonymous with the said Formula (3).

  As described above, the structural unit (III) is preferably a structural unit derived from maleic anhydride, and examples of the monomer that gives the structural unit (III) include a monomer represented by the following formula: It is done.

In the above formula, R ¹⁰ is a monovalent organic group having 1 to 20 carbon atoms. c is an integer of 0-2. However, when R ¹⁰ is plural, the plurality of R ¹⁰ may be different even in the same.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 degreeC-150 degreeC, 40 degreeC-150 degreeC is preferable, and 50 degreeC-140 degreeC is more preferable. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, and more preferably 1 hour to 10 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobis (2-methylpropionate); benzoyl peroxide And peroxide radical initiators such as t-butyl hydroperoxide and cumene hydroperoxide. Of these, AIBN is preferred. These can be used alone or in combination of two or more.

  As the polymerization solvent, any solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and capable of dissolving the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These can be used alone or in combination of two or more.

  The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the polymerization reaction is completed, the polymer is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] Although the polystyrene conversion weight average molecular weight (Mw) by the gel permeation chromatography (GPC) of a polymer is not specifically limited, It is preferable that it is 1,000-50,000, and is 1,000-40,000. More preferably, it is particularly preferably 1,000 to 30,000. [A] By setting Mw of the polymer within the specific range, a resist film having a sufficient dynamic contact angle can be obtained, and the developability of the resist film is improved.

  [A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually 1.0 to 5.0, preferably 1.0 to 4.0. 1.0 to 2.0 is more preferable.

  In addition, Mw and Mn were obtained by using monodisperse polystyrene under analytical conditions of a TOSOH GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) at a flow rate of 1.0 mL / min, elution solvent at a column temperature of 40 ° C. It was measured by standard gel permeation chromatography.

<[B] polymer>
The [B] polymer contained in the composition is a component that is a main component of the resist film, has an acid-dissociable group, and is a base polymer having a fluorine atom content smaller than that of the [A] polymer. . By containing the [B] polymer, the [A] polymer is unevenly distributed on the resist film surface when the resist film is formed from the composition containing the [A] polymer and the [B] polymer. It becomes. The fluorine atom content can be measured by ¹³ C-NMR.

  [B] The fluorine atom content in the polymer is usually less than 5% by mass, preferably 0% by mass to 4.9% by mass, more preferably 0%, when the entire fluorine-containing polymer is 100% by mass. It is mass%-4 mass%. [B] By making the fluorine atom content ratio in the polymer within the above range, the water repellency of the resist film surface formed from the composition containing the [B] polymer and the [A] polymer can be increased. .

[Structural unit (IV)]
[B] The polymer is not particularly limited as long as it has an acid-dissociable group and has a fluorine atom content smaller than that of the polymer [A], but is usually a structural unit having an acid-dissociable group represented by the following formula (Hereinafter also referred to as “structural unit (IV)”). The acid dissociable group refers to a group that substitutes a hydrogen atom in a polar functional group such as a hydroxyl group or a carboxyl group, and dissociates in the presence of an acid. Thereby, a structural unit (IV) will produce a polar group by the effect | action of an acid. Therefore, it is preferable at the point which can make the solubility with respect to the alkali developing solution of the part exposed in the exposure process high.

In the above formula, R ¹¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{12 to} R ¹⁴ are each independently a linear or branched alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 14 carbon atoms which may have a substituent. However, R ¹² and R ¹³ may form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom bonded to each other.

Examples of the linear or branched alkyl group having 1 to 10 carbon atoms represented by R ^{12 to} R ¹⁴ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a 1-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, i-pentyl group, sec-pentyl group, neo-pentyl group, tert-pentyl group, n-hexyl group, i-hexyl group, Examples include n-heptyl group, i-heptyl group, n-octyl group, i-octyl group, n-nonyl group, i-nonyl group, n-decyl group, i-decyl group and the like. Examples of the aryl group having 6 to 14 carbon atoms represented by R ^{12 to} R ¹⁴ include a phenyl group, a naphthyl group, and an anthranyl group. Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms that may be formed together with the carbon atom in which R ¹² and R ¹³ are bonded to each other include cyclopropane, cyclobutane, cyclopentane, Examples include groups in which two hydrogen atoms have been removed from an alicyclic hydrocarbon such as cyclohexane, dicyclopentane, norbornane, tricyclodecane, tetracyclododecane, and adamantane.

  Examples of the structural unit (IV) include a structural unit represented by the following formula.

In the above formula, R ¹¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Of these, R ⁹ is a methyl group, and together with the carbon atoms to which R ¹¹ and R ¹² are bonded to each other, a group in which two hydrogen atoms are removed from adamantane is formed, and R ¹⁰ has a carbon number of 1 to The structure of 4 linear alkyl groups is preferred as the structural unit (IV).

  [B] The content of the structural unit (IV) in the polymer is preferably 5 mol% to 70 mol%, and preferably 10 mol% to 60 mol% with respect to all the structural units constituting the [A] polymer. More preferred. In addition, the [B] polymer may contain 2 or more types of structural units (IV).

[Structural unit (V)]
[B] The polymer may contain a structural unit containing at least one structure selected from the group consisting of a lactone structure and a cyclic carbonate structure (hereinafter also referred to as “structural unit (V)”). [B] When a polymer contains a structural unit (V), the adhesiveness with the board | substrate of the resist film obtained from the said composition improves.

  Examples of the structural unit (V) include a structural unit represented by the following formula.

In the above formula, R ¹² is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  [B] The content of the structural unit (V) in the polymer is preferably 0 mol% to 70 mol%, preferably 5 mol% to 60 mol%, based on all structural units constituting the [B] polymer. More preferred. In addition, the [B] polymer may contain 2 or more types of structural units (V).

<[B] Polymer Synthesis Method>
[B] As a method for synthesizing the polymer, for example, a monomer corresponding to each predetermined structural unit can be produced by polymerizing in a suitable solvent using a radical polymerization initiator. For example, a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction; a solution containing a monomer and a solution containing a radical initiator Respectively, a method of dropping a solution into a reaction solvent or a monomer-containing solution to cause a polymerization reaction; a plurality of types of solutions each containing a monomer, and a solution containing a radical initiator, It is preferable to synthesize by a method such as a method of dropping it into a reaction solvent or a solution containing a monomer to cause a polymerization reaction.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 degreeC-180 degreeC, and 40 degreeC-160 degreeC is preferable. Although dripping time changes with conditions, such as reaction temperature, the kind of initiator, and the monomer made to react, it is 30 minutes-8 hours normally, and 45 minutes-6 hours are preferable. Further, the total reaction time including the dropping time varies depending on the conditions as well as the dropping time, but is usually 30 minutes to 8 hours, and preferably 45 minutes to 7 hours.

  As the radical initiator, the solvent, and the polymer recovery method used for the polymerization, the same compounds and methods as those described in [A] Polymer Synthesis Method can be applied.

  [B] The Mw of the polymer is usually 1,000 to 300,000, preferably 2,000 to 200,000, and more preferably 3,000 to 100,000. By making Mw into the said specific range, it is preferable from a viewpoint which the heat resistance and developability as a resist improve.

<[C] acid generator>
[C] The acid generator is a compound that generates an acid by light that has passed through a mask in an exposure process, which is one process of forming a resist pattern. The composition of the [C] acid generator in the composition is incorporated as a part of the polymer even in the form of a compound as described later (hereinafter, this aspect is also referred to as “[C] acid generator” as appropriate). Or both of these embodiments.

  [C] Examples of the acid generator include onium salt compounds and sulfonimide compounds. Of these, onium salt compounds are preferred.

  Examples of the onium salt compounds include sulfonium salts (including tetrahydrothiophenium salts) and iodonium salts.

  Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro- n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept- -Yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium par Fluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylphosphonium 1,1, Examples include 2,2-tetrafluoro-6- (1-adamantane carbonyloxy) -hexane-1-sulfonate. Among these, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylphosphonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) -hexane-1 -Sulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophene Nitro 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- (6-n-butoxynaphthalene-2 Yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene- 2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydro Thiophenium perfluoro-n-octance Phonates, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, etc. Can be mentioned. Of these tetrahydrothiophenium salts, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) Tetrahydrothiophenium perfluoro-n-octane sulfonate and 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butane sulfonate are preferred.

  Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t -Butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetra Le Oro ethanesulfonate. Of these iodonium salts, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate is preferred.

  Examples of the sulfonimide compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [ 2.2.1] Hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3- Dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene -2,3-dicarboximide and the like.

  [C] The acid generator may be used alone or in combination of two or more. [C] The amount used when the acid generator is an “agent” is from the viewpoint of ensuring the sensitivity and developability of the coating film formed from the composition, with respect to 100 parts by mass of the polymer (B). 0.1 parts by mass or more and 30 parts by mass or less are preferable, and 1 part by mass or more and 20 parts by mass or less are more preferable.

<[D] Acid diffusion controller>
The composition may contain a [D] acid diffusion controller as a suitable component. [D] The acid diffusion control agent controls the diffusion phenomenon of the acid generated from the [C] acid generator upon exposure in the resist film, and suppresses an undesirable chemical reaction in the non-exposed region, and the resulting radiation sensitive This improves the storage stability of the functional resin composition, improves the resolution of the resist, and suppresses changes in the line width of the resist pattern due to fluctuations in the holding time from exposure to development processing. An extremely excellent composition is obtained.

  [D] Examples of the acid diffusion controller include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

  Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′-tetra Methylethylenediamine, 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-amino) Phenyl) -2- (4-hydroxyphenyl) propane, 1, -Bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylaminoethyl) ether Bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine and the like.

  Examples of amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, Examples thereof include benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, and isocyanuric acid tris (2-hydroxyethyl).

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea and the like. Is mentioned.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles; pyridines; piperazines; piperidines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidineethanol, 3-piperidino-1,2-propanediol, morpholine 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2. 2.2] octane and the like.

  [D] As the acid diffusion controlling agent, a photodisintegrating base that is exposed to light and generates a weak acid can be used. As an example of the photodegradable base, there is an onium salt compound that is decomposed by exposure and loses acid diffusion controllability. Examples of the onium salt compound include a sulfonium salt compound and an iodonium salt compound.

  [D] The acid diffusion controller may be used alone or in combination of two or more. [D] The acid diffusion control agent acid content is preferably 15 parts by mass or less from the viewpoint of improving the sensitivity as a resist with respect to 100 parts by mass of the polymer [B].

<Other optional components>
In addition to the [A] polymer, the [C] acid generator, and the [B] polymer, which is a preferred component, and the [D] acid diffusion controller, the composition may be used as long as the effects of the present invention are not impaired. For example, it can contain other optional components such as an uneven distribution accelerator, a surfactant, and a sensitizer. Each of these optional components may be used alone or in combination of two or more. Moreover, the compounding quantity of another arbitrary component can be suitably determined according to the objective. Hereinafter, each component will be described in detail.

[Uneven distribution promoter]
The uneven distribution promoter has an effect of segregating the [A] polymer on the resist film surface more efficiently. Examples of the uneven distribution promoter include low molecular compounds having a relative dielectric constant of 30 or more and 200 or less and a boiling point of 100 ° C. or more at 1 atm. Examples of such compounds include lactone compounds, carbonate compounds, and nitrile compounds v.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

  Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

  Examples of the nitrile compound include succinonitrile. Examples of the polyhydric alcohol include glycerin.

[Surfactant]
A surfactant is a component that exhibits an effect of improving coatability, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate are listed. Examples of commercially available products include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, manufactured by Tochem Products), MegaFac F171, F173 (above, manufactured by Dainippon Ink & Chemicals), Fluorad FC430, FC431 ( As above, manufactured by Sumitomo 3M, Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, manufactured by Asahi Glass) ) And the like.

[Sensitizer]
The sensitizer absorbs energy other than the energy of radiation absorbed by the [C] acid generator, and transmits the energy to the [C] acid generator in the form of, for example, electrons and radicals, thereby It has the effect of increasing the amount of acid produced, and has the effect of improving the “apparent sensitivity” of the composition.

  Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Method for preparing radiation-sensitive resin composition for immersion exposure>
The composition is prepared by uniformly mixing other optional components in addition to the [A] polymer, [B] polymer, [C] acid generator and [D] acid diffusion controller as a suitable component. Is done. The composition is preferably used in the form of a solution dissolved in a suitable solvent.

  As a solvent used for the preparation of the composition, a solvent that uniformly dissolves essential components and optional components and does not react with each component is used. Examples of the solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, Diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylene Glycol monomethyl ether, dipro (Poly) alkylene glycol monoalkyl ethers such as lenglycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether; acetic acid Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol mono-n-butyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-propyl ether acetate , Diethylene glycol acetate mono-n-butyl ether, propylene glycol acetate Acetic acid (poly) alkylene glycol monoalkyl ethers such as ethyl monomethyl ether, propylene glycol monoethyl ether acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate; diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl Other ethers such as ether and tetrahydrofuran; methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, diacetone alcohol (4-hydroxy-4-methylpentan-2-one), 4-hydroxy-4-methylhexane-2 Ketones such as -one; diacetates such as propylene glycol diacetate, 1,3-butylene glycol diacetate, and 1,6-hexanediol diacetate Alkyl lactates such as methyl lactate and ethyl lactate; ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl formate, i-pentyl acetate, 3- Methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, n-butyl propionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl butyrate, n-propyl butyrate, i-propyl butyrate N-butyl butyrate, ethyl hydroxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, N-propyl pyruvate, methyl acetoacetate, acetoacetate , Other esters such as ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate and ethyl 2-oxobutyrate; aromatic hydrocarbons such as toluene and xylene; N-methylpyrrolidone Amides such as N, N-dimethylformamide and N, N-dimethylacetamide. The solvent can be used alone or in combination of two or more.

  Although it is not limited as content of a solvent, the total solid content density | concentration of each component except the solvent of the said composition from viewpoints of the applicability | paintability of the said composition obtained, stability, etc. is 5 mass%-50 mass%. The quantity which becomes 10 mass%-40 mass% is more preferable. The composition solution thus prepared can be used after being filtered using a Millipore filter or the like having a pore diameter of about 0.5 μm.

<Method for forming resist pattern>
As a method of forming a resist pattern using the composition,
(1) The process of forming a coating film on a board | substrate using the said composition (2) The process of arrange | positioning the liquid for immersion exposure to the said formed coating film, and performing the immersion exposure via the liquid for immersion exposure ,
(3) A step of developing a coating film subjected to immersion exposure to form a resist pattern.

  In the step (1), the solution of the composition is applied onto a substrate such as a silicon wafer or a wafer coated with aluminum by an appropriate application means such as spin coating, cast coating, roll coating, and the like. Form a coating film. Moreover, after apply | coating the said composition solution so that it may become a desired film thickness, the solvent in a coating film is volatilized by prebaking as needed. The thickness of the coating film is preferably about 10 nm to 500 nm. Although prebaking heating conditions change with composition of a radiation sensitive resin composition, about 30 to 200 degreeC is preferable and 50 to 150 degreeC is more preferable.

  In the step (2), an immersion exposure liquid is disposed on the coating film formed in the step (1), and immersion exposure is performed by irradiating radiation through the immersion exposure liquid. Examples of the immersion exposure liquid include pure water, long-chain or cyclic aliphatic compounds, and fluorine-based inert liquids. The radiation is appropriately selected from visible rays, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams, etc., depending on the type of [C] acid generator to be used. ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm) is preferred, and ArF excimer laser (wavelength 193 nm) is more preferred. The exposure conditions such as the exposure amount can be appropriately selected according to the blending composition of the radiation-sensitive resin composition, the type of additive, and the like.

  Moreover, it is preferable to perform post-baking after exposure. By post-baking, the dissociation reaction of the acid-dissociable group in the resin component can proceed smoothly. The post-baking heating condition is appropriately adjusted depending on the composition of the radiation-sensitive resin composition, but is usually preferably 30 ° C to 200 ° C and 50 ° C to 170 ° C.

  In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, for example, an organic or inorganic antireflection film can be formed on the substrate to be used. Moreover, in order to prevent the influence of the basic impurity etc. which are contained in environmental atmosphere, a protective film can also be provided, for example on a coating film. Furthermore, in order to prevent the [C] acid generator and the like from flowing out of the photoresist film during the immersion exposure, an immersion protective film can be provided on the coating film, for example. Moreover, these techniques can be used together.

  In step (3), the immersion-exposed coating film is developed to form a resist pattern. Examples of the developer used in the development step include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, and di-n-propylamine. , Triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] An alkaline aqueous solution in which at least one of alkaline compounds such as 5-nonene is dissolved is preferable.

  The concentration of the alkaline aqueous solution is preferably 10% by mass or less from the viewpoint that the non-exposed portion is hardly dissolved in the developer.

EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example. Incidentally, ¹ H-NMR analysis of the compound, ¹³ C-NMR analysis to determine the fluorine atom content of the polymer, nuclear magnetic resonance apparatus (manufactured by JEOL, JNM-ECX400) was used.

<Synthesis of monomer>
[Synthesis Example 1]
A toluene solution of oxalyl chloride was prepared, and a toluene solution (0.25 mol / L) of a monomer (M-1-1) represented by the following formula as a precursor was added dropwise at room temperature over 10 minutes. After the dropwise addition, several drops of DMF were added and stirred for 2 hours to prepare acid chloride (M-1-2) represented by the following formula. In an ice bath, a toluene solution of triethylamine (2.0 mol / L) was added dropwise over 1 hour, stirred for 1 hour, and then a toluene solution of tert-butyl alcohol (1.5 mol / L) was added dropwise over 30 minutes. did. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with a toluene / sodium hydrogen carbonate aqueous solution to obtain a monomer (M-1) represented by the following formula (yield: 70%).

¹ H-NMR (400 MHz, CDCl ₃ ): δ 6.33 (1H, dd), 6.07 (1H, m), 3.49 (1H, br), 3.01 (1H, br), 2.62 (1H, dd), 1.50 (2H, m), 1.42 (1H, s), 1.39 (9H, s)

[Synthesis Example 2]
A toluene solution of oxalyl chloride was prepared, and the toluene solution (0.25 mol / L) of the precursor monomer (M-1-1) was added dropwise at room temperature over 10 minutes. After the dropwise addition, several drops of DMF were added and stirred for 2 hours to prepare acid chloride (M-1-2) represented by the above formula. In an ice bath, a toluene solution of triethylamine (2.0 mol / L) was dropped over 1 hour and stirred for 1 hour, and then a toluene solution of 2,2,2-trifluoroethanol (1.5 mol / L) was added. It was added dropwise over 30 minutes. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with an aqueous toluene / sodium hydrogen carbonate solution to obtain a monomer (M-2) represented by the following formula (yield: 75%).

¹ H-NMR (400 MHz, CDCl 3): δ 6.38 (1H, dd), 6.14 (1H, m), 4.60 (2H, m), 3.49 (1H, br), 3.01 ( 1H, br), 2.62 (1H, dd), 1.50 (2H, m), 1.42 (1H, s)

[Synthesis Example 3]
A toluene solution of oxalyl chloride was prepared, and the toluene solution (0.25 mol / L) of the precursor monomer (M-1-1) was added dropwise at room temperature over 10 minutes. After dropping, several drops of DMF were added and stirred for 2 hours to prepare the acid chloride (M-1-2). Toluene solution of triethylamine (2.0 mol / L) was dropped over 1 hour in an ice bath, stirred for 1 hour, and then a toluene solution of hexafluoroisopropyl alcohol (1.5 mol / L) was dropped over 30 minutes. did. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separating and purifying with an aqueous toluene / sodium hydrogen carbonate solution, a monomer (M-3) represented by the following formula was obtained (yield 73%).

¹ H-NMR (400 MHz, CDCl 3): δ 6.38 (1H, dd), 6.14 (1H, m), 5.59 (1H, m), 3.49 (1H, br), 3.01 ( 1H, br), 2.62 (1H, dd), 1.50 (2H, m), 1.42 (1H, s)

[Synthesis Example 4]
A toluene solution of oxalyl chloride was prepared, and the toluene solution (0.25 mol / L) of the precursor monomer (M-1-1) was added dropwise at room temperature over 10 minutes. After dropping, several drops of DMF were added and stirred for 2 hours to prepare the acid chloride (M-1-2). A toluene solution of triethylamine (2.0 mol / L) was dropped in an ice bath over 1 hour and stirred for 1 hour, followed by a toluene solution of m-trifluoromethylphenol (1.5 mol / L) over 30 minutes. And dripped. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with an aqueous toluene / sodium hydrogen carbonate solution to obtain a monomer (M-4) represented by the following formula (yield: 75%).

¹ H-NMR (400 MHz, CDCl 3): δ 8.23 (2H, d), 7.55 (2H, d), 6.38 (1H, dd), 6.14 (1H, m), 3.49 ( 1H, br), 3.01 (1H, br), 2.62 (1H, dd), 1.50 (2H, m), 1.42 (1H, s)

[Synthesis Example 5]
A toluene solution of oxalyl chloride was prepared, and a toluene solution (0.25 mol / L) of a monomer (M-5-1) represented by the following formula as a precursor was added dropwise at room temperature over 10 minutes. After the dropwise addition, several drops of DMF were added and stirred for 2 hours to prepare acid chloride (M-5-2) represented by the following formula. In an ice bath, a toluene solution of triethylamine (2.0 mol / L) was dropped over 1 hour and stirred for 1 hour, and then a toluene solution of 2,2,2-trifluoroethanol (1.5 mol / L) was added. It was added dropwise over 30 minutes. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with an aqueous toluene / sodium hydrogen carbonate solution to obtain a monomer (M-5) (yield 72%).

¹ H-NMR (400 MHz, CDCl 3): δ 6.31 (1H, dd), 6.09 (1H, m), 4.53 (2H, m), 3.45 (1H, br), 3.06 ( 1H, br), 2.65 (1H, dd), 1.56 (1H, m), 1.50 (1H, m) 1.46 (1H, s)

[Synthesis Example 6]
A toluene solution of oxalyl chloride was prepared, and a toluene solution (0.25 mol / L) of the precursor monomer (M-5-1) was added dropwise at room temperature over 10 minutes. After dropping, several drops of DMF were added and stirred for 2 hours to prepare the acid chloride (M-5-2). A toluene solution of triethylamine (2.0 mol / L) was dropped in an ice bath over 1 hour and stirred for 1 hour, followed by a toluene solution of m-trifluoromethylphenol (1.5 mol / L) over 30 minutes. And dripped. Further, a toluene solution of 1,4-diazabicyclo [2.2.2] octane (0.075 mol / L) was added dropwise over 10 minutes and stirred for 12 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with an aqueous toluene / sodium hydrogen carbonate solution to obtain a monomer (M-6) represented by the following formula (yield 68%).

¹ H-NMR (400 MHz, CDCl 3): δ 8.23 (2H, d), 7.55 (2H, d), 6.31 (1H, dd), 6.09 (1H, m), 3.45 ( 1H, br), 3.06 (1H, br), 2.65 (1H, dd), 1.56 (1H, m), 1.50 (1H, m) 1.46 (1H, s)

[Synthesis Example 7]
A toluene solution of oxalyl chloride was prepared, and a toluene solution (0.25 mol / L) of a precursor monomer (M-7-1) represented by the following formula was added dropwise at room temperature over 10 minutes. After the dropwise addition, several drops of DMF were added and stirred for 2 hours to prepare acid chloride (M-7-2) represented by the following formula. In an ice bath, a toluene solution of triethylamine (2.0 mol / L) was dropped over 1 hour and stirred for 1 hour, and then a toluene solution of 2,2,2-trifluoroethanol (1.5 mol / L) was added. The mixture was added dropwise over 30 minutes, returned to room temperature, and stirred for 1.5 hours. After adding 1N hydrochloric acid and stirring for 30 minutes, the organic layer was taken out and the solvent was distilled off. Separation and purification were performed with an aqueous toluene / sodium hydrogen carbonate solution to obtain a monomer (M-7) represented by the following formula (yield 78%).

¹ H-NMR (400 MHz, CDCl 3): δ 7.20 (2H, s), 4.64 (4H, q)

<[A] Synthesis of polymer>
[Synthesis Example 8]
A 500 mL three-necked flask equipped with a thermometer was charged with 50 mol% of monomer (M-1) and 50 mol% of maleic anhydride and purged with nitrogen for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer. AIBN was added thereto as a polymerization initiator and reacted for 6 hours. Then, it cooled until it became 30 degrees C or less, and obtained the polymer solution. In addition, mol% of each monomer represents mol% with respect to the total amount of monomers, and the usage ratio of the initiator was 2 mol% with respect to the total amount of the monomer and the initiator. After completion of the polymerization, the mixture was poured into 250 g of hexane to precipitate a viscous white solid. Thereafter, the precipitated white solid was filtered off. The filtered white solid was washed twice with 50 g of hexane and filtered. Thereafter, it was dried at 50 ° C. for 17 hours to obtain a polymer (A-1) (70 g, yield 70%). Mw of the polymer (A-1) is 4,500, Mw / Mn is 1.44, and as a result of ¹³ C-NMR analysis, the content of each structural unit derived from each monomer is (M-1). : Maleic anhydride = 50: 50 (mol%). The fluorine atom content was 14.6 mol%.

[Synthesis Examples 2 to 13]
Each polymer was obtained in the same manner as in Synthesis Example 8 except that the monomers of the types and blending amounts shown in Table 1 were mixed. The physical property values are also shown in Table 1. In addition, the monomers (M-8) and (M-9) in Table 1 are compounds represented by the following formulas, respectively.

<[B] Synthesis of polymer>
32 g (50 mol%) of the compound (M-10) represented by the following formula and 28 g (50 mol%) of the compound (M-11) represented by the following formula are dissolved in 120 g of 2-butanone, and further a polymerization initiator. As a result, 20.94 g of AIBN was added to obtain a monomer solution. On the other hand, a three-necked flask charged with 60 g of 2-butanone was purged with nitrogen for 30 minutes. After purging with nitrogen, the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution was added dropwise using a dropping funnel over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled to 30 ° C. or less by water cooling, and poured into 1,200 g of methanol to precipitate a white powder. Thereafter, the precipitated white powder was filtered off. The filtered white powder was washed twice with 240 g of methanol in the form of a slurry and filtered. Then, it dried at 50 degreeC for 17 hours, and obtained the polymer (B-1) of the white powder (42g, 70% of yield). The polymer (B-1) had Mw of 6,200 and Mw / Mn of 1.5. As a result of ¹³ C-NMR analysis, the content of each structural unit derived from each monomer was (M-10) :( M-11) = 47.5: 52.5 (mol%).

<Preparation of radiation-sensitive resin composition for immersion exposure>
The [C] acid generator and the [D] acid diffusion controller used for the preparation of the radiation sensitive resin composition for immersion exposure are shown below.

<[C] acid generator>
Compound represented by the following formula

<[D] Acid diffusion controller>
D-1: t-Butyl-4-hydroxy-1-piperidinecarboxylate

[Example 1]
5 parts by mass of polymer (A-1), 100 parts by mass of polymer (B-1), 9.0 parts by mass of acid generator (C-1), 5.6 parts by mass of acid diffusion controller (D-1) In addition, 2,800 parts by mass of propylene glycol monomethyl ether acetate and 1,200 parts by mass of cyclohexanone were mixed as a solvent to prepare a radiation sensitive resin composition for immersion exposure.

[Examples 2 to 12 and Comparative Example 1]
Except having mixed each component of the kind and compounding quantity shown in Table 2, it operated similarly to Example 1 and obtained the radiation sensitive resin composition for each immersion exposure.

<Evaluation>
A resist pattern was formed as follows for the prepared radiation-sensitive resin composition for immersion exposure, and the following evaluation was performed. The evaluation results are shown in Table 2.

[Backward contact angle (°)]
A coating film was formed on the substrate using each radiation-sensitive resin composition for immersion exposure. Thereafter, the receding contact angle (°) of the formed coating film was measured in the following procedure using DSA-10 manufactured by KRUS under an environment of room temperature 23 ° C., humidity 45%, and normal pressure. The DSA-10 needle is cleaned with acetone and isopropyl alcohol before measurement, then water is injected into the needle, and the wafer is set on the wafer stage. The height of the stage is adjusted so that the distance between the wafer surface and the tip of the needle is 1 mm or less, and then water is discharged from the needle to form a 25 μL water droplet on the wafer. And a contact angle was measured every second. The average value was calculated for the contact angles of a total of 20 points from the time when the contact angle was stabilized, and was taken as the receding contact angle.
Each substrate was coated with a radiation-sensitive resin composition for immersion exposure on an 8-inch silicon wafer to form a 110 nm-thickness film, and then subjected to soft baking (SB) at 120 ° C. for 50 seconds. In Table 2 was “after SB”.
Each of the radiation-sensitive resin compositions for immersion exposure was applied onto an 8-inch silicon wafer to form a coating film having a thickness of 110 nm, and SB was performed at 120 ° C. for 50 seconds. Thereafter, development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 10 seconds using a GP nozzle of a developing device (manufactured by Tokyo Electron Ltd., Clean Track ACT8), rinsed with pure water for 15 seconds, and then shaken off and dried at 2,000 rpm. The receding contact angle of the substrate was “after 10 seconds development” in Table 2.
Each of the radiation-sensitive resin compositions for immersion exposure was applied onto an 8-inch silicon wafer to form a coating film having a thickness of 110 nm, and SB was performed at 120 ° C. for 50 seconds. Thereafter, development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 30 seconds using a GP nozzle of a developing device (manufactured by Tokyo Electron Ltd., Clean Track ACT8), rinsed with pure water for 30 seconds, and then shaken off and dried at 2,000 rpm. The receding contact angle of the substrate was “after 30 seconds development” in Table 2.

[Development defects]
Each of the radiation-sensitive resin compositions for immersion exposure was applied onto a 12-inch silicon wafer on which a lower antireflection film (ARC66, manufactured by Nissan Chemical Industries) was formed, thereby forming a coating film having a thickness of 100 nm. Next, this coating film was exposed through a mask pattern using an ArF excimer laser immersion exposure apparatus (NSR S610C, manufactured by NIKON) under the conditions of NA = 1.3, ratio = 0.812, and Crosspore. After the exposure, post-baking was performed at 95 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, washed with water and dried to form a positive resist pattern. At this time, the exposure amount for forming a line and space having a width of 55 nm was determined as the optimum exposure amount. A line and space having a line width of 55 nm was formed on the entire surface of the wafer with this optimum exposure amount to obtain a defect inspection wafer. Note that a scanning electron microscope (S-9380, manufactured by Hitachi High-Technologies) was used for length measurement. Thereafter, the number of defects on the defect inspection wafer was measured using a KLA-Tencor KLA2810. The measured defects were classified into those judged to be derived from the resist and foreign matters derived from the outside. After classification, “A” (determined as good) when the total number of defects determined from resist (number of defects) was 100 / wafer or less, “B” (defect) when 100 / wafer or more Judgment).

  As is apparent from the results in Table 2, it can be confirmed that when the composition is used, the receding contact angle after SB is greatly reduced after 10 seconds development and after 30 seconds development as compared with the comparative example. It was found that the contact angle change is excellent. It was also found that development defects are less likely to occur when the composition is used.

  In the radiation-sensitive resin composition for immersion exposure according to the present invention, the resist film formed in the immersion exposure process exhibits a moderately large dynamic contact angle during exposure, while the dynamic contact angle is large after alkali development. Deteriorating characteristics can be exhibited, and the time required for changing the dynamic contact angle can be shortened. As a result, in addition to suppressing the elution of acid generators from the resist film, the resist film surface has excellent water drainage, enabling high-speed scan exposure and compatibility with the developer during development. Therefore, the occurrence of development defects can be suppressed and a good resist pattern can be formed. Accordingly, the composition can be suitably used as a chemically amplified resist for manufacturing semiconductor devices.

Claims (12)

[A] A radiation-sensitive resin composition for immersion exposure, comprising a polymer having a fluorine atom and an alkali-dissociable group and having an alicyclic group in the main chain, and [C] an acid generator. [A] The radiation-sensitive resin composition for immersion exposure according to claim 1, wherein the polymer contains a structural unit (I) represented by the following formula (1).

(In Formula (1), R < ¹ > -R < ⁴ > is respectively independently a hydrogen atom, a fluorine atom, or a C1-C20 monovalent organic group. A is 0 or 1. b is It is an integer from 0 to 2.) The radiation-sensitive resin composition for immersion exposure according to claim 2, wherein at least one of R ^{1 to} R ⁴ is a fluorine atom or a trifluoromethyl group. ^4. The radiation-sensitive resin composition for immersion exposure according to claim 2, wherein at least one of the R ^{1 to} R ⁴ is a group represented by the following formula (2).

(In formula (2), R ⁵ is an alkali dissociable group.) R ⁵ is a linear or branched alkyl group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or a carbon number having 6 to 20 which may be substituted with a fluorine atom or a fluorinated alkyl group. The radiation-sensitive resin composition for immersion exposure according to claim 4, which is an aromatic group. [A] The radiation-sensitive resin composition for immersion exposure according to any one of claims 1 to 5, wherein the polymer further comprises a structural unit (II) represented by the following formula (3).

(In Formula (3), R ⁶ and R ⁷ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a divalent linking group. .) The radiation-sensitive resin composition for immersion exposure according to claim 6, wherein at least one of R ⁸ and R ⁹ is an oxygen atom, and R ⁶ or R ⁷ bonded to the oxygen atom is an alkali dissociable group. 8. The liquid immersion exposure according to claim 7, wherein the alkali dissociable group represented by R ⁶ or R ⁷ bonded to the oxygen atom is a linear or branched fluorinated alkyl group having 1 to 10 carbon atoms. Radiation sensitive resin composition.   [A] The immersion exposure according to any one of claims 1 to 8, wherein the polymer further comprises a structural unit (III) having -C (= O) -OC (= O)-. Radiation sensitive resin composition.   The radiation-sensitive resin composition for immersion exposure according to claim 9, wherein the structural unit (III) is a structural unit derived from maleic anhydride.   The immersion exposure according to any one of claims 1 to 10, further comprising a base polymer having an acid dissociable group [B] and a fluorine atom content smaller than that of the polymer [A]. Radiation sensitive resin composition.   [D] The radiation-sensitive resin composition for immersion exposure according to any one of claims 1 to 11, further comprising an acid diffusion controller.