JP2008242303A - Composition for forming upper antireflection film, and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming an upper antireflection film capable of thoroughly reducing standing-wave effect and blob defects in lithography and having superior solubility in an alkali developer, and to provide a resist pattern forming method. <P>SOLUTION: The composition for forming an upper antireflection film contains a polymer (A), soluble in an alkali developer and having an aromatic group, and at least one of a radiation-sensitive acid generator (B) and a compound (C) having sulfonic acid residue. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composition for forming an upper antireflection film and a method for forming a resist pattern. More specifically, the present invention is a composition for forming an upper antireflection film that can sufficiently reduce the standing wave effect and blob defects in lithography (particularly 193 nm lithography) and has excellent solubility in an alkaline developer. And a resist pattern forming method.

Conventionally, in the field of microfabrication represented by the manufacture of integrated circuit elements, in order to obtain a higher degree of integration, the processing size in lithography has been miniaturized. Recently, an ArF excimer laser (wavelength: 193 nm), There is a need for a lithography technique that enables fine processing at a level of about 200 nm or less using an F ₂ excimer laser (wavelength 157 nm) or the like. As a resist suitable for irradiation with such an excimer laser, a component having an acid dissociable functional group and a component that generates an acid upon irradiation with radiation (hereinafter referred to as “exposure”) (hereinafter referred to as “acid generator”). )) And a resist utilizing the chemical amplification effect (hereinafter referred to as “chemically amplified resist”) have been proposed. As this chemically amplified resist, for example, a resist containing a resin having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and an acid generator has been proposed. In this resist, the t-butyl ester group or t-butyl carbonate group present in the resin is dissociated by the action of an acid generated by exposure, so that the resin has an acidic group composed of a carboxyl group or a phenolic hydroxyl group. As a result, the phenomenon that the exposure region of the photoresist film becomes easily soluble in an alkali developer is utilized.
In such lithography, in the future, it is required to form finer patterns, and in particular, studies on microfabrication using an ArF excimer laser (wavelength 193 nm) have become active.

  However, since the radiation normally used in the lithography process has a single wavelength, the incident radiation and the radiation reflected by the upper and lower interfaces of the photoresist film interfere with each other in the photoresist film, resulting in a “standing wave effect”. ”Or“ multiple interference effect ”, that is, even if the exposure dose is constant, if the thickness of the photoresist film changes, the effective exposure dose to the photoresist film changes due to mutual interference within the film. This causes a problem that adversely affects the formation of the resist pattern. For example, the coating film thickness may change due to slight differences in resist composition, viscosity, resist coating conditions, etc., or there may be a difference in coating film thickness due to a step in the substrate (the concave part is more prominent than the convex part). When the thickness is increased), the effective exposure amount for the photoresist film changes due to the difference in the film thickness, and the pattern dimension varies or the dimensional accuracy of the resist pattern decreases.

  In order to solve such problems related to the standing wave effect, a method has been proposed in which an upper antireflection film is formed on the photoresist film to suppress reflection on the surface of the photoresist film and to reduce multiple interference in the film. ing. For example, Non-Patent Document 1 describes that a standing wave effect is reduced by laminating polysiloxane, polyethyl vinyl ether, polyvinyl alcohol or the like as an upper antireflection film on a photoresist film. In this case, the reflection suppression effect on the surface of the photoresist film mainly depends on the refractive index and the film thickness of the antireflection film, and the ideal refractive index of the upper antireflection film is √n (n is the refractive index of the resist). The ideal film thickness of the upper antireflection film is assumed to be an odd multiple of λ / 4m (λ is the wavelength of radiation and m is the refractive index of the upper antireflection film).

J. et al. Electrochem. Soc. , Vol. 137, no. 12, p. 3900 (1990)

  Since the refractive index of a general resist is 1.6 to 1.8, an upper antireflection film having a refractive index of 1.4 or less is required to sufficiently suppress the standing wave effect. However, the refractive index of the upper antireflection film made of polysiloxane, polyethyl vinyl ether or polyvinyl alcohol is generally 1.5 or more, and the standing wave effect cannot be sufficiently suppressed. As the size becomes finer and the management of the pattern line width becomes stricter, an upper antireflection film having a smaller refractive index is required.

  In addition, the upper antireflection film needs not only to have a low refractive index but also to have a high transmittance. This is because if the upper antireflection film has strong absorption, the light reaching the resist film is weakened, resulting in a problem that sensitivity is lowered and throughput is lowered. Therefore, it is preferable that the absorption coefficient (k value) of the upper antireflection film is small, and it can be said that 0.25 or less is practical.

  Also, in recent lithography processes in the manufacture of integrated circuit elements, defects that occur during resist film development have become problems, such as bridge defects and scum defects in line and space patterns, opening defect defects and scum defects in contact hole patterns, etc. Is mentioned. One of the causes of these defects is that a hardly soluble substance in the developer is reattached on the resist or the substrate at the time of rinsing after development, and this defect is called a blob defect.

  Improvement of this blob defect leads to an increase in yield in the manufacture of integrated circuit elements, and thus many studies have been made so far, but no satisfactory solution has yet been found.

  The present invention has been made to overcome such problems. In lithography (especially 193 nm lithography), the standing wave effect and blob defects can be sufficiently reduced, and the solubility in an alkaline developer is improved. It is an object of the present invention to provide a composition for forming an upper antireflection film and a method for forming a resist pattern which are excellent in the above.

〔式（１）において、Ｒ^１は、炭素数１〜１０の直鎖状或いは分岐状のアルキル基、炭素数３〜２０の脂環式アルキル基或いはその誘導体、水酸基、カルボキシル基、アルキルエーテル基、アルキルオキシカルボニル基、又はアルキルカルボニルオキシ基を表し、Ｚは炭素数４〜１２の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表し、ｍは０〜４の整数であり、ｎは１〜４の整数である。尚、Ｒ^１が複数存在する場合、相互に同一であっても異なっていてもよい。〕
［３］前記重合体（Ａ）が、下記式（２）で表される繰り返し単位、及び下記式（３）で表される繰り返し単位のうちの少なくとも一方を含んでおり、ゲルパーミエーションクロマトグラフィー法により測定される重量平均分子量が１０００〜１０００００である前記［１］又は［２］に記載の上層反射防止膜形成用組成物。

〔式（２）において、Ｒ^２〜Ｒ^８は、それぞれ、水素原子、−ＯＨ、−ＣＯＯＨ、又は−ＳＯ_３Ｈを表す。〕

〔式（３）において、Ｒ^９〜Ｒ^１５は、それぞれ、水素原子、−ＯＨ、−ＣＯＯＨ、又は−ＳＯ_３Ｈを表す。〕
［４］前記重合体（Ａ）が、更に、下記式（４）〜（７）で表される繰り返し単位のうちの少なくとも１種を含む前記［３］に記載の上層反射防止膜形成用組成物。

〔式（４）において、Ｒ^１６は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表し、Ａは単結合、カルボニル基又はカルボニルオキシ基を表し、Ｂは単結合又はイミノ基を表し、Ｄは単結合、炭素数１〜２０の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表す。〕

〔式（５）において、Ｒ^１７は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表す。〕

〔式（６）において、Ｒ^１８は水素原子、炭素数１〜１２のアルキル基又は炭素数１〜１２のフッ素化アルキル基を表す。〕

〔式（７）において、Ｒ^１９は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表し、Ｐは単結合、カルボニル基又はカルボニルオキシ基を表し、Ｑは単結合、炭素数１〜２０の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表し、Ｒ^２０及びＲ^２１は、それぞれ、水素原子、炭素数１〜４のアルキル基又は炭素数１〜４のフッ素化アルキル基を表す。〕
［５］前記重合体（Ａ）は、下記式（８）で表される繰り返し単位、及び下記式（９）で表される繰り返し単位を含む前記［１］乃至［４］のいずれかに記載の上層反射防止膜形成用組成物。

［６］（１）基板上にフォトレジスト膜を形成する工程と、（２）前記［１］乃至［５］のいずれかに記載の上層反射防止膜形成用組成物を用いて、前記フォトレジスト膜上に上層反射防止膜を形成する工程と、（３）前記上層反射防止膜が形成された前記フォトレジスト膜の所用領域に放射線を照射し、露光する工程と、（４）現像して前記上層反射防止膜を除去する工程と、を備えることを特徴とするレジストパターン形成方法。 Means for achieving the above object are as follows.
[1] At least one of a polymer (A) that is soluble in an alkali developer and has an aromatic group, and a radiation-sensitive acid generator (B) and a compound (C) having a sulfonic acid residue And an upper antireflection film-forming composition comprising:
[2] The composition for forming an upper antireflection film according to [1], wherein the compound (C) having the sulfonic acid residue is a compound represented by the following formula (1).

[In the formula (1), R ¹ represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms or a derivative thereof, a hydroxyl group, a carboxyl group, an alkyl ether group. Represents an alkyloxycarbonyl group or an alkylcarbonyloxy group, and Z represents a linear, branched or alicyclic hydrocarbon group having 4 to 12 carbon atoms or an aromatic hydrocarbon which may have a substituent. Represents a group, m is an integer of 0 to 4, and n is an integer of 1 to 4. In the case where R ¹ there are a plurality, it may be the same or different from each other. ]
[3] The polymer (A) contains at least one of a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3), and gel permeation chromatography. The composition for forming an upper antireflection film according to [1] or [2], wherein the weight average molecular weight measured by a method is 1000 to 100,000.

In [Equation ^(2), R 2 ~R ⁸ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ]

In [Equation ^{(3), R} 9 ~R ¹⁵ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ]
[4] The composition for forming an upper antireflection film according to [3], wherein the polymer (A) further contains at least one of repeating units represented by the following formulas (4) to (7): object.

[In the formula (4), R ¹⁶ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, A represents a single bond, a carbonyl group or a carbonyloxy group, and B represents a single bond or an imino group. , D represents a single bond, a linear, branched or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group which may have a substituent. ]

In [Equation (5), R ¹⁷ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group. ]

In [Equation ^{(6), R 18} represents a hydrogen atom, an alkyl group or fluorinated alkyl group having 1 to 12 carbon atoms having 1 to 12 carbon atoms. ]

[In the formula (7), R ¹⁹ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, P represents a single bond, a carbonyl group or a carbonyloxy group, Q represents a single bond, 20 represents a linear, branched or alicyclic hydrocarbon group or an aromatic hydrocarbon group which may have a substituent, and R ²⁰ and R ²¹ each represent a hydrogen atom, a carbon number of 1 to 4 alkyl group or a C1-C4 fluorinated alkyl group is represented. ]
[5] The polymer (A) is any one of [1] to [4], including a repeating unit represented by the following formula (8) and a repeating unit represented by the following formula (9). A composition for forming an upper antireflection film.

[6] (1) A step of forming a photoresist film on a substrate, and (2) the photoresist using the composition for forming an upper antireflection film according to any one of [1] to [5] A step of forming an upper antireflection film on the film; (3) a step of irradiating a desired region of the photoresist film on which the upper antireflection film is formed and exposing; and (4) development and And a step of removing the upper antireflection film.

  According to the present invention, in lithography (particularly 193 nm lithography), it is possible to sufficiently reduce the standing wave effect and blob defects, and to form an upper antireflection film excellent in solubility in an alkaline developer. It is. Therefore, the present invention can be used very suitably for the manufacture of LSIs that are expected to be further miniaturized in the future.

Hereinafter, embodiments of the present invention will be described in detail.
[1] Composition for forming an upper antireflection film The composition for forming an upper antireflection film of the present invention is a polymer (A) which is soluble in an alkali developer and has an aromatic group (hereinafter simply referred to as “heavy” Compound (A) ”), radiation-sensitive acid generator (B) [hereinafter also simply referred to as“ acid generator (B) ”] and compound (C) having a sulfonic acid residue (hereinafter simply“ At least one of the compounds (also referred to as “compound (C)”).

The “polymer (A)” in the composition for forming an upper antireflection film of the present invention is particularly as long as the effects of the present invention can be obtained and it is soluble in an alkali developer and has an aromatic group. It is not limited.
Examples of the aromatic group include a phenyl group, a naphthyl group, an acenaphthyl group, a thiophenyl group, and the like. Among these, a naphthyl group and an acenaphthyl group are particularly preferable.

  Examples of the polymer (A) include a repeating unit represented by the following formula (2) [hereinafter referred to as “repeat unit (1)”] and a repeating unit represented by the following formula (3) [hereinafter, Of the “repeating unit (2)” and having a weight average molecular weight of 1000 to 100,000 as measured by gel permeation chromatography is preferred.

〔式（２）において、Ｒ^２〜Ｒ^８は、それぞれ、水素原子、−ＯＨ、−ＣＯＯＨ、又は−ＳＯ_３Ｈを表す。〕

In [Equation ^(2), R 2 ~R ⁸ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ]

〔式（３）において、Ｒ^９〜Ｒ^１５は、それぞれ、水素原子、−ＯＨ、−ＣＯＯＨ、又は−ＳＯ_３Ｈを表す。〕

In [Equation ^{(3), R} 9 ~R ¹⁵ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ]

  Each of the repeating units (1) and (2) contained in the polymer (A) may be one kind or two or more kinds.

The polymer (A) contains at least one of —OH, —COOH and —SO ₃ H in addition to the repeating units (1) and (2) in order to promote alkali developer solubility. Repeating units containing seeds can be included. Specific examples of the repeating unit include repeating units represented by the following formulas (4), (5), (6) and (7) [hereinafter referred to as “repeating unit (3)” and “repeating unit (4), respectively”. ”,“ Repeat unit (5) ”and“ repeat unit (6) ”. And the like. In the present invention, it is preferable to include at least one of these repeating units (3) to (6).

〔式（４）において、Ｒ^１６は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表し、Ａは単結合、カルボニル基又はカルボニルオキシ基を表し、Ｂは単結合又はイミノ基を表し、Ｄは単結合、炭素数１〜２０の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表す。〕

[In the formula (4), R ¹⁶ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, A represents a single bond, a carbonyl group or a carbonyloxy group, and B represents a single bond or an imino group. , D represents a single bond, a linear, branched or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group which may have a substituent. ]

〔式（５）において、Ｒ^１７は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表す。〕

In [Equation (5), R ¹⁷ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group. ]

〔式（６）において、Ｒ^１８は水素原子、炭素数１〜１２のアルキル基又は炭素数１〜１２のフッ素化アルキル基を表す。〕

In [Equation ^{(6), R 18} represents a hydrogen atom, an alkyl group or fluorinated alkyl group having 1 to 12 carbon atoms having 1 to 12 carbon atoms. ]

〔式（７）において、Ｒ^１９は水素原子、メチル基、ヒドロキシメチル基又はトリフルオロメチル基を表し、Ｐは単結合、カルボニル基又はカルボニルオキシ基を表し、Ｑは単結合、炭素数１〜２０の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表し、Ｒ^２０及びＲ^２１は、それぞれ、水素原子、炭素数１〜４のアルキル基又は炭素数１〜４のフッ素化アルキル基を表す。〕

[In the formula (7), R ¹⁹ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, P represents a single bond, a carbonyl group or a carbonyloxy group, Q represents a single bond, 20 represents a linear, branched or alicyclic hydrocarbon group or an aromatic hydrocarbon group which may have a substituent, and R ²⁰ and R ²¹ each represent a hydrogen atom, a carbon number of 1 to 4 alkyl group or a C1-C4 fluorinated alkyl group is represented. ]

  Here, as the aromatic hydrocarbon group which may have a linear, branched or alicyclic hydrocarbon group or a substituent having 1 to 20 carbon atoms in D of the formula (4), for example, , Methylene group, ethylene group, propylene group such as 1,3-propylene group or 1,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group , Undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonacamethylene group, 1-methyl-1 , 3-propylene group, 2-methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4 Saturated chain hydrocarbon groups such as butylene, 2-methyl-1,4-butylene, methylidene, ethylidene, propylidene or 2-propylidene; arylene such as phenylene and tolylene, 1,3- Cyclobutylene groups such as cyclobutylene groups, cyclopentylene groups such as 1,3-cyclopentylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, and cyclooctylene groups such as 1,5-cyclooctylene groups A monocyclic hydrocarbon ring group such as a cycloalkylene group having 3 to 10 carbon atoms such as a group; a norbornylene group such as a 1,4-norbornylene group or a 2,5-norbornylene group; a 1,5-adamantylene group; 6-adamantylene group and other adamantylene groups, etc. 2-4 cyclic hydrocarbon hydrocarbon groups such as hydrocarbon ring groups having 4 to 20 carbon atoms, substituted and unsubstituted phenyl Ren group, and the like.

  Preferred monomers that give the repeating unit (3) represented by the formula (4) include, for example, vinyl sulfonic acid, allyl sulfonic acid, (meth) acrylic acid 1-sulfoxyethyl ester, 4-vinyl-1 -Benzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, etc. are mentioned.

  Moreover, as a preferable monomer which gives the repeating unit (4) represented by said Formula (5), (meth) acrylic acid, (alpha) -trifluoromethylacrylic acid etc. are mentioned, for example.

Examples of the alkyl group having 1 to 12 carbon atoms in R ¹⁸ of the formula (6) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, and 1 -Methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, etc. Chain or branched alkyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups and other cycloalkyl groups, bicyclo [2.2.1] heptan-2-yl groups, bicyclo [2. 2.2] Alicyclic hydrocarbon groups such as octan-2-yl group, adamantane-1-yl group, and adamantane-2-yl group.
Examples of the fluorinated alkyl group having 1 to 12 carbon atoms in R ¹⁸ include a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 12 carbon atoms are substituted with fluorine atoms. it can.

  Examples of the aromatic hydrocarbon group which may have a linear, branched or alicyclic hydrocarbon group or a substituent having 1 to 20 carbon atoms in Q of the formula (7) include a methylene group, an ethylene group, Propylene group such as 1,3-propylene group or 1,2-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodeca Methylene group, tridecamethylene group, tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonacamethylene group, 1-methyl-1,3-propylene group, 2 -Methyl-1,3-propylene group, 2-methyl-1,2-propylene group, 1-methyl-1,4-butylene group, 2-methyl Saturated chain hydrocarbon groups such as -1,4-butylene group, methylidene group, ethylidene group, propylidene group or 2-propylidene group; arylene groups such as phenylene group and tolylene group; cyclohexane such as 1,3-cyclobutylene group 3 carbon atoms such as butylene group, cyclopentylene group such as 1,3-cyclopentylene group, cyclohexylene group such as 1,4-cyclohexylene group, cyclooctylene group such as 1,5-cyclooctylene group, etc. Monocyclic hydrocarbon ring group such as 10 to cycloalkylene group; norbornylene group such as 1,4-norbornylene group or 2,5-norbornylene group, 1,5-adamantylene group, 2,6-adamantylene group and the like And a bridged cyclic hydrocarbon ring group such as a hydrocarbon ring group having 2 to 4 cyclic carbon atoms of 4 to 20 carbon atoms such as an adamantylene group, a substituted or unsubstituted phenylene group, and the like.

Furthermore, as a C1-C4 alkyl group in R < ²⁰ > and R < ²¹ > of said Formula (7), a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, 2- A methylpropyl group, a 1-methylpropyl group, a t-butyl group, etc. are mentioned.
Examples of the fluorinated alkyl group having 1 to 4 carbon atoms in R ²⁰ and R ²¹ include a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 4 carbon atoms are substituted with fluorine atoms. Can be mentioned.
R ²⁰ and R ²¹ may be the same or different.

Moreover, as a preferable monomer which gives the repeating unit (6) represented by the formula (7), for example, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2- Hydroxy-3-propyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1) -Trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester 2-([5- (1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl (meth) acrylic acid Ester, (meth) acrylic acid 3 - {[8- (1 ', 1', 1'-trifluoro-2'-trifluoromethyl-2'-hydroxy) propyl] tetracyclo [6.2.1.1 ^{3 , 6} . 0 ^2,7 ] dodecyl} ester and the like.

  In particular, the polymer (A) preferably contains at least a repeating unit represented by the following formula (8) and a repeating unit represented by the following formula (9). In this case, the standing wave effect can be further reduced as an antireflection film, and the solubility in an alkali developer can be improved.

In the polymer (A), the total content of the repeating units (1) and (2) is not particularly limited, but when all the repeating units in the polymer (A) are 100 mol%, It is preferable that it is 20-80 mol%, More preferably, it is 30-70 mol%, More preferably, it is 40-60 mol%. When the content ratio is 20 to 80 mol%, the standing wave effect as the antireflection film can be sufficiently reduced, and it has a sufficient transmittance at a wavelength of 193 nm, and has a good pattern. And an increase in sensitivity can be suppressed.
Further, the total content of the repeating units (3) to (6) that promote the solubility of the alkali developer is not particularly limited, but when all the repeating units in the polymer (A) are 100 mol%, It is preferable that it is 20-80 mol%, More preferably, it is 30-70 mol%, More preferably, it is 40-60 mol%. When this content ratio is 20 to 80 mol%, sufficient solubility in the developer can be obtained, and undissolved or scum can be suppressed during development.

  The polymer (A) has a weight average molecular weight (hereinafter referred to as “Mw”) measured by a gel permeation chromatography method (GPC method) of 1000 to 100,000, preferably 1500 to 10,000, more preferably. 2000-7000. If this Mw is less than 1000, the film forming ability may be insufficient. On the other hand, if it exceeds 100000, a sufficient dissolution rate with respect to the developer cannot be obtained, and undissolved matter and scum are not formed. May occur.

In addition, the polymer (A) is, for example, a polymerizable unsaturated monomer corresponding to each repeating unit, radical polymerization start of hydroperoxides, dialkyl peroxides, diacyl peroxides, azo compounds, etc. It can manufacture by superposing | polymerizing in a suitable solvent in presence of a chain transfer agent using an agent as needed.
Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, Cycloalkanes such as norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethane, hexamethylene dibromide, chlorobenzene; ethyl acetate Saturated carboxylic acid esters such as n-butyl acetate, i-butyl acetate and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone and 2-heptanone; tetrahydrofuran, dimethoxyethanes, Ethers such as diethoxyethanes It can be mentioned. These solvents may be used alone or in combination of two or more.
Moreover, the reaction temperature in the said polymerization is 40-120 degreeC normally, Preferably it is 50-100 degreeC, and reaction time is 1 to 24 hours normally, Preferably it is 3 to 12 hours.

  The “acid generator (B)” in the composition for forming an upper antireflection film of the present invention is a substance that generates an acid upon exposure to radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray. is there. Examples of the acid generator (B) include onium salt compounds, halogen-containing compounds, sulfone compounds, sulfonic acid ester compounds, and quinonediazide compounds.

Specific examples of the acid generator (B) 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, triphenylsulfonium 2- (3-tetracyclo [4.4.0.1 ^2,5 .1 ^7,10 Dodecanyl) -1,1-difluoroethanesulfonate, triphenylsulfonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, triphenylsulfonium camphorsulfonate,

4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2. 2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexyl-phenyl diphenyl sulfonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7, 10} ] dodecanyl) -1,1-difluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 4-cyclohexylphenyldiphenylsulfonium camphorsulfonate,

4-t-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-t-butylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-t-butylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-t-butylphenyl Diphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-t-butylphenyldiphenylsulfonium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10] dodecanyl) -1,1-difluoroethanesulfonate, 4-t-butylphenyl diphenyl sulfonium N, N-bis (nonafluoro -n- butanesulfonyl) imidate, 4-t-butyl Phenyldi Phenylsulfonium camphorsulfonate, tri (4-t-butylphenyl) sulfonium trifluoromethanesulfonate, tri (4-t-butylphenyl) sulfonium nonafluoro-n-butanesulfonate, tri (4-t-butylphenyl) sulfonium perfluoro- n-octanesulfonate, tri (4-t-butylphenyl) sulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, tri (4-t- Butylphenyl) sulfonium 2- (3-tetracyclo [4.4.0.1 ^2,5 7. ^7,10 ] dodecanyl) -1,1-difluoroethanesulfonate, tri (4-t-butylphenyl) sulfonium N, N -Bis (nonafluoro-n-butanesulfonyl) imi Dating, tri (4-t-butylphenyl) sulfonium camphorsulfonate,

Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-tetrafluoroethane sulfonate, diphenyliodonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonate, diphenyliodonium N, N-bis ( Nonafluoro-n-butanesulfonyl) imidate, diphenyliodonium camphorsulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodo Nimononafluoro-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-tetrafluoroethanesulfonate, bis (4-t- butylphenyl) iodonium 2- (3-tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl ) -1,1-difluoroethanesulfonate, bis (4-t-butylphenyl) iodonium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, bis (4-t-butylphenyl) iodonium camphorsulfonate,

1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (4-n-Butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2-bicyclo [2.2. 1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10 ] dodecanyl) -1,1-difluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiofe Nium camphorsulfonate,

1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (3,5-Dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2. 1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2- (3-tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10 ] dodecanyl) -1,1-difluoro Ethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium N, N-bis (nonafluoro-n-butanesulfonyl) imidate, 1- (3,5-dimethyl-4-hydroxyphenyl) Tetrahydrothiophenium camphorsulfonate,

N- (trifluoromethanesulfonyloxy) succinimide, N- (nonafluoro-n-butanesulfonyloxy) succinimide, N- (perfluoro-n-octanesulfonyloxy) succinimide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethane sulfonyloxy) succinimide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethanesulfonyloxy) succinimide, N- (camphorsulfonyloxy) succinimide,

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-dicarboxy imide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethane-sulfonyloxy) bicyclo [2.2.1] hept -5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and the like.

The acid generator (B) may be used alone or in combination of two or more.
Moreover, it is preferable that content of this acid generator (B) is 0.1-15 mass parts with respect to 100 mass parts of polymers (A), More preferably, 0.1-10 mass parts, More preferably, it is 0.1-5 mass parts. When this content is 0.1 to 15 parts by mass, blob defects can be reduced and a good resist pattern shape can be obtained. Moreover, when content of an acid generator (B) is less than 0.1 mass part, there exists a possibility that the effect which reduces a blob defect may become inadequate. On the other hand, when the amount exceeds 15 parts by mass, the top loss of the resist pattern after development is remarkably increased, and it may be difficult to obtain a rectangular resist pattern.

  The “compound (C)” in the composition for forming an upper antireflection film of the present invention is a compound having a sulfonic acid residue. Although this compound (C) is not specifically limited, For example, it is preferable that it is a compound represented by following General formula (1).

〔式（１）において、Ｒ^１は、炭素数１〜１０の直鎖状或いは分岐状のアルキル基、炭素数３〜２０の脂環式アルキル基或いはその誘導体、水酸基、カルボキシル基、アルキルエーテル基、アルキルオキシカルボニル基、又はアルキルカルボニルオキシ基を表し、Ｚは炭素数４〜１２の直鎖状、分岐状、脂環式の炭化水素基或いは置換基を有していてもよい芳香族炭化水素基を表し、ｍは０〜４の整数であり、ｎは１〜４の整数である。尚、Ｒ^１が複数存在する場合、相互に同一であっても異なっていてもよい。〕

[In the formula (1), R ¹ represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms or a derivative thereof, a hydroxyl group, a carboxyl group, an alkyl ether group. Represents an alkyloxycarbonyl group or an alkylcarbonyloxy group, and Z represents a linear, branched or alicyclic hydrocarbon group having 4 to 12 carbon atoms or an aromatic hydrocarbon which may have a substituent. Represents a group, m is an integer of 0 to 4, and n is an integer of 1 to 4. In the case where R ¹ there are a plurality, it may be the same or different from each other. ]

Examples of the linear or branched alkyl group having 1 to 10 carbon atoms of R ¹ in the formula (1) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, An n-decyl group etc. are mentioned.

Examples of the alicyclic alkyl group having 3 to 20 carbon atoms of R ¹ in the formula (1) or a derivative thereof include norbornane, tricyclodecane, tetracyclododecane, adamantane, cyclobutane, cyclopentane, cyclohexane, Groups composed of alicyclic rings derived from cycloalkanes such as cycloheptane and cyclooctane, and groups composed of these alicyclic rings include, for example, methyl group, ethyl group, n-propyl group, i-propyl group A group substituted by one or more of linear, branched or cyclic alkyl groups such as n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group, etc., hydroxyl group , A group substituted with one or more by a carboxyl group, a hydroxyalkyl group, a cyano group, a cyanoalkyl group, and the like.

  Furthermore, examples of the linear, branched, and alicyclic hydrocarbon groups having 4 to 12 carbon atoms in Z in the formula (1) include, for example, a 1-methyl-1,3-propylene group, 2- Methyl-1,3-propylene group, 1,4-butylene group, 1-methyl-1,4-butylene group, 2-methyl-1,4-butylene group, 1,5-pentylene group, 1,1-dimethyl -1,4-butylene group, 2,2-dimethyl-1,4-butylene group, 1,2-dimethyl-1,4-butylene group, 1,6-hexylene group; 1,3-cyclobutylene group, etc. Monocycles such as cyclobutylene groups such as cyclobutylene groups, 1,3-cyclopentylene groups, cyclohexylene groups such as 1,4-cyclohexylene groups, and cyclooctylene groups such as 1,5-cyclooctylene groups Hydrocarbon ring group; 1,4-norbornylene group or , 5-norbornylene norbornylene group such as a group, 1,5-adamantylene group and a crosslinked cyclic hydrocarbon ring groups such as adamantylene groups such as 2,6-adamantylene group.

  Moreover, as an aromatic hydrocarbon group which may have a substituent in Z of said Formula (1), a phenyl group, a naphthyl group, a thiophenyl group etc. are mentioned, for example.

  Specific examples of the compound (C) include trifluoromethanesulfonic acid, pentafluoroethanesulfonic acid, heptafluoropropanesulfonic acid, nonafluorobutanesulfonic acid, dodecafluoropentanesulfonic acid, and tridecafluorohexanesulfonic acid. , Pentadecafluoroheptanesulfonic acid, heptadecafluorooctanesulfonic acid, octadecafluorononanesulfonic acid, fluoromethanesulfonic acid, difluoromethanesulfonic acid, 1,1-difluoroethanesulfonic acid, 2,2,2-trifluoroethane Sulfonic acid, 1,1-difluoropropanesulfonic acid, 1,1,2,2-tetrafluoropropansulfonic acid, 3,3,3-trifluoropropanesulfonic acid, 2,2,3,3,4,4 , 4-Heptafluorobutane Sulfonic acid, 3,3,4,4,4 fluoroalkyl sulfonic acids such as pentafluorobutane sulfonic acid,

  Methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, isopropanesulfonic acid, butanesulfonic acid, isobutanesulfonic acid, 1,1-dimethylethanesulfonic acid, pentanesulfonic acid, 1-methylbutanesulfonic acid, 2-methylbutanesulfone Acids, alkyl sulfonic acids such as 3-methylbutanesulfonic acid, neopentanesulfonic acid, hexanesulfonic acid, hebutanesulfonic acid, octanesulfonic acid, nonanesulfonic acid, decanesulfonic acid, benzenesulfonic acid, 2-toluenesulfonic acid, 3-toluenesulfonic acid, 4-toluenesulfonic acid, 4-ethylbenzenesulfonic acid, 4-propylbenzenesulfonic acid, 4-butylbenzenesulfonic acid, 4- (t-butyl) benzenesulfonic acid, 2,5-dimethylbenzenesulfone Acid, 2-me Tylenesulfonic acid, 2,4-dinitrobenzenesulfonic acid, 4-chlorobenzenesulfonic acid, 4-bromobenzenesulfonic acid, 4-fluorobenzenesulfonic acid, 2,3,4,5,6-pentafluorobenzenesulfonic acid, 4 -Hydroxybenzenesulfonic acid, 2-hydroxybenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, 3-sulfosalicylic acid, 4-sulfosalicylic acid, 5-sulfosalicylic acid, 1-naphthylsulfonic acid, 2-naphthylsulfonic acid, cyclohexylsulfonic acid Arylsulfonic acids such as 2-hydroxycyclohexylsulfonic acid, 3-hydroxycyclohexylsulfonic acid, 4-sulfobenzoic acid, 4-sulfoaniline,

  Aralkylsulfonic acids such as benzylsulfonic acid and phenethylsulfonic acid, cyclic sulfonic acids such as camphorsulfonic acid, benzenesulfonic acid, 2-hydroxybenzenesulfonic acid, 3-hydroxybenzenesulfonic acid, 3-sulfosalicylic acid, 4-sulfosalicylic acid 5-sulfosalicylic acid, 1-naphthylsulfonic acid, 2-naphthylsulfonic acid, cyclohexylsulfonic acid, 2-hydroxycyclohexylsulfonic acid, 3-hydroxycyclohexylsulfonic acid, poly (4-styrenesulfonic acid), polyvinylnaphthalenesulfonic acid, etc. Is mentioned.

The said compound (C) may be used independently and may be used in mixture of 2 or more types.
Moreover, it is preferable that content of the said compound (C) is 0.1-15 mass parts with respect to 100 mass parts of polymers (A), More preferably, it is 0.1-10 mass parts, More preferably. Is 0.1 to 5 parts by mass. When this content is 0.1 to 15 parts by mass, blob defects can be reduced and a good resist pattern shape can be obtained. Moreover, when this content is less than 0.1 mass part, there exists a possibility that the effect of reducing a blob defect may become inadequate. On the other hand, when the amount exceeds 15 parts by mass, the top loss of the resist pattern after development is remarkably increased, and it may be difficult to obtain a rectangular resist pattern.

The composition for forming an upper antireflection film of the present invention may contain a surfactant for the purpose of improving coating properties, antifoaming properties, leveling properties and the like.
Examples of the surfactant include BM-1000, BM-1100 (above, manufactured by BM Chemie), MegaFuck F142D, F172, F173, F183 [above, manufactured by Dainippon Ink & Chemicals, Inc.] , FLORARD FC-135, FC170C, FC-430, FC-431 [above, manufactured by Sumitomo 3M Co., Ltd.], Surflon S-112, S-113, S-131, S-131 [above, Asahi Glass Co., Ltd.], SH-28PA, -190, -193, SZ-6032, SF8428 [above, manufactured by Toray Dow Corning Silicone Co., Ltd.], Emulgen A-60, 104P, 306P [above, Kao ( Fluorosurfactants marketed under trade names such as “made by Co., Ltd.” can be used. In addition, these surfactants may be used independently and may be used in mixture of 2 or more types.

  The content of the surfactant is preferably 5 parts by mass or less with respect to 100 parts by mass of the polymer (A).

  In addition, the composition for forming an upper antireflection film of the present invention usually has a total solid concentration of 0.1 to 15% by mass, preferably 0.1 to 10% by mass, when used. It is preferable to use one prepared by dissolving in a solvent and then filtering through a filter having a pore size of about 20 nm, for example.

As the solvent, a solvent that hardly deteriorates the lithography performance by causing intermixing with the photoresist film when the composition for forming an upper antireflection film of the present invention is applied onto the photoresist film is used. It is done.
Examples of such solvents include monohydric alcohols, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ethers, cyclic ethers, higher hydrocarbons, and aromatics. Examples thereof include hydrocarbons, ketones, esters, water and the like.

  The monohydric alcohol is preferably a monohydric alcohol having 4 to 8 carbon atoms. Specifically, for example, 2-methyl-1-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-2-pentanol, 4-methyl 2-pentanol, 2-ethyl-1-butanol, 2,4-dimethyl-3-pentanol and the like.

Examples of the polyhydric alcohols include ethylene glycol and propylene glycol.
Examples of the alkyl ethers of the polyhydric alcohol include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol. Examples include ethyl methyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether.
Examples of the alkyl ether acetates of the polyhydric alcohol include ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate and the like.

Examples of the ethers include dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl. Ether, di-tert-butyl ether, dipentyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether, cyclohexyl-2- Propyl ether, cyclopentyl butyl ether, cyclopentyl-te t- butyl ether, cyclohexyl ether, cyclohexyl -tert- butyl ether and the like.
Examples of the cyclic ethers include tetrahydrofuran and dioxane.

Examples of the higher hydrocarbons include decane, dodecane, and undecane.
Examples of the aromatic hydrocarbons include benzene, toluene, xylene and the like.
Examples of the ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, and the like.
Examples of the esters include ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate , Methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-ethoxypropionate and the like.

Among these, monohydric alcohols, ethers, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, and higher hydrocarbons are preferable.
In addition, these solvents may be used independently and may be used in mixture of 2 or more types.

Further, the refractive index (n value) at a wavelength of 193 nm of the film formed using the composition for forming an upper antireflection film of the present invention is preferably 1.5 or less, more preferably 1.25 to 1. .45, more preferably 1.25 to 1.4. When the refractive index is 1.5 or less, reflection of light in the laminate is suppressed, and the low standing wave effect can be reduced, which is preferable.
This refractive index can be measured with an ellipsometer after coating the upper antireflection film-forming composition on a silicon wafer having a diameter of 8 inches.

[2] Resist pattern forming method The resist pattern forming method of the present invention comprises:
(1) a step of forming a photoresist film on the substrate [hereinafter referred to as “step (1)”];
(2) Using the composition for forming an upper antireflection film, a step of forming an upper antireflection film on the photoresist film (hereinafter referred to as “step (2)”);
(3) A step of irradiating and exposing a desired region of the photoresist film on which the upper antireflection film is formed (hereinafter referred to as “step (3)”);
(4) A step of developing and removing the upper antireflection film [hereinafter referred to as “step (4)”].

In the step (1), a photoresist film is formed on the substrate.
Specifically, the resist composition solution is applied onto the substrate by an appropriate application method such as spin coating, cast coating, roll coating, or the like so that the resulting photoresist film has a predetermined thickness, and then pre-baked ( Hereinafter, it is referred to as “pre-bake (PB)”), and the solvent in the coating film is volatilized to form a photoresist film.

  As the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used. In order to maximize the potential of the photoresist film to be formed, for example, as disclosed in Japanese Patent Publication No. 6-12452, an organic or inorganic reflective material is used on the substrate to be used. A prevention film may be formed in advance.

The resist composition solution is not particularly limited, and can be appropriately selected according to the intended use of the photoresist. As a specific resist composition solution, for example, a chemically amplified resist composition containing an acid generator or the like is, for example, a solid content concentration of 0.1 to 20% by mass in an appropriate solvent. For example, a resist composition solution prepared by filtering with a filter having a pore diameter of about 30 nm can be used. A commercially available resist solution can be used as it is.
The resist composition solution may be a positive type or a negative type, but is preferably a positive type resist composition solution. In a chemically amplified positive resist, an acid-dissociable organic group in the polymer is dissociated by the action of an acid generated from an acid generator by exposure to generate, for example, a carboxyl group. As a result, the resist is exposed. The solubility of the portion in the alkali developer is increased, and the exposed portion is dissolved and removed by the alkali developer, whereby a positive resist pattern is obtained.

In the step (2), an upper antireflection film is formed on the photoresist film using the upper antireflection film forming composition. The above description can be applied as it is to the composition for forming an upper antireflection film.
Specifically, the upper antireflection film-forming composition is applied onto the photoresist film by an appropriate application method such as spin coating, cast coating, roll coating or the like so that the obtained upper antireflection film has a predetermined thickness. After coating, the upper antireflection film is formed by baking.
As the thickness of the upper antireflection film is closer to an odd multiple of λ / 4m (λ is the wavelength of radiation and m is the refractive index of the upper antireflection film), the antireflection effect at the upper interface of the photoresist film increases. . For this reason, it is preferable to make the thickness of the upper antireflection film close to this value.
In the present invention, any one of the pre-baking after the application of the resist composition solution in the step (1) and the baking after the application of the upper layer film-forming composition in the step (2) is performed in order to simplify the process. Can be omitted.

In the step (3), the desired region of the photoresist film on which the upper antireflection film is formed is irradiated with radiation to perform exposure.
The radiation is appropriately selected according to the components constituting the photoresist film and the combination of the photoresist film and the upper antireflection film. For example, various kinds of radiation such as visible rays; ultraviolet rays such as g rays and i rays; far ultraviolet rays such as excimer lasers; X rays such as synchrotron radiation; and charged particle rays such as electron beams can be selectively used. Among these, an ArF excimer laser (wavelength 193 nm) and a KrF excimer laser (wavelength 248 nm) are preferable, and an ArF excimer laser is particularly preferable.
In order to improve the resolution, pattern shape, developability, etc. of the photoresist film, baking (hereinafter referred to as “PEB”) is preferably performed after exposure. The baking temperature is appropriately adjusted depending on the resist composition used and the like, but is usually about 30 to 200 ° C., preferably 50 to 150 ° C.

In the step (4), the photoresist film and the upper antireflection film are simultaneously removed by development.
Specifically, after the photoresist film is developed with a developer and washed, a desired resist pattern is formed, and the upper antireflection film is separated separately during the development or after the development. It is completely removed without having to go through any steps.

Examples of the developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethyl. Ethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5,4,0] -7-undecene, 1,5-diazabicyclo- [4 , 3,0] -5-nonane and the like.
In addition, an appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, a surfactant, and the like can be added to these developers.
In addition, after developing using alkaline aqueous solution, generally it wash | cleans with water and dries.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In addition, the description of “part” and “%” in the description of this example is based on mass unless otherwise specified.

[1] Synthesis of polymer (A) Hereinafter, synthesis examples of the respective polymers [polymers (A-1) to (A-3)] will be described. The physical properties of each polymer obtained in each synthesis example were evaluated in the following manner.

(1) Mw
Monodispersed polystyrene using Tosoh Corporation GPC columns (G2000HXL: 2, G3000HXL: 1, G4000HXL: 1), flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, column temperature 40 ° C Was measured by a gel permeation chromatography method.
(2) Copolymerization ratio
^The copolymerization ratio of each monomer was determined by the area ratio of the peaks derived from the side chain groups of each monomer in the absorption spectra by ¹ H-NMR and ¹³ C-NMR.

<Synthesis Example 1>
A separable flask equipped with a stirrer, a thermometer, and a condenser tube was charged with 30 g of tetrahydrofuran (hereinafter referred to as “THF”), and after bubbling nitrogen gas for 15 minutes, 10.4809 g of 2-vinylnaphthalene, α-trifluoromethyl 9.5911 g of t-butyl acrylate and 1.87779 g of 2,2′-azobis (dimethyl 2-methylpropionate) were added, and the internal temperature was raised to 45 ° C. After 1 hour, the internal temperature was raised, the mixture was refluxed at about 70 ° C., reacted for 8 hours, and then cooled to 25 ° C. Subsequently, the copolymer was obtained by vacuum-drying and removing a solvent.
This copolymer had an Mw of 3.5 × 10 ³ and a copolymerization ratio (mol%) of 2-vinylnaphthalene / α-trifluoromethylacrylic acid of 50/50. This copolymer is referred to as “polymer (A-1)”.

<Synthesis Example 2>
A separable flask equipped with a stirrer, a thermometer, and a condenser tube was charged with 30 g of methyl ethyl ketone, and after bubbling nitrogen gas for 15 minutes, 8.9840 g of 2-vinylnaphthalene, 8.1596 g of α-trifluoromethylacrylic acid, maleic anhydride The acid 2.8600g 2,2'-azobis (dimethyl 2-methylpropionate) 2.0122g was added, and the internal temperature was raised to 45 degreeC. After 1 hour, the internal temperature was raised and reacted at 70 ° C. for 8 hours, and then cooled to 25 ° C. Next, 3 g of a 1% oxalic acid aqueous solution was slowly added dropwise, the internal temperature was raised to 70 ° C., and the reaction was performed for 2 hours. Thereafter, the reaction solution was washed with 50 g of water three times, and vacuum-dried to remove the solvent to obtain a copolymer.
This copolymer had an Mw of 3.8 × 10 ³ and a copolymerization ratio (mol%) of 2-vinylnaphthalene / α-trifluoromethylacrylic acid / maleic acid of 40/40/20. This copolymer is referred to as “polymer (A-2)”.

<Synthesis Example 3>
A separable flask equipped with a stirrer, a thermometer and a condenser tube was charged with 30 g of THF, and after bubbling nitrogen gas for 15 minutes, 9.3063 g of 2-vinylnaphthalene, 9.3915 g of α-trifluoromethylacrylic acid, 2-sulfo 1.3000 g of ethyl methacrylate and 1.8528 g of 2,2′-azobis (dimethyl 2-methylpropionate) were added, and the internal temperature was raised to 45 ° C. After 1 hour, the internal temperature was raised, the mixture was refluxed at about 70 ° C., reacted for 8 hours, and then cooled to 25 ° C. Subsequently, the copolymer was obtained by vacuum-drying and removing a solvent.
This copolymer has an Mw of 3.7 × 10 ³ and a copolymerization ratio (mol%) of 2-vinylnaphthalene / α-trifluoromethylacrylic acid / 2-sulfoethyl methacrylate of 45/50/5. there were. This copolymer is referred to as “polymer (A-3)”.

[2] Preparation of composition for forming upper antireflection film <Examples 1 to 9>
After blending the acid generator (B) and the compound (C) shown in Table 1 into 100 parts of each polymer (A) shown in Table 1, 4-methyl-2-pentanol was added to obtain a solid content concentration of 1 %. Then, it filtered with the membrane filter with the hole diameter of 0.2 micrometer, and obtained the composition for each upper layer anti-reflective film formation of Examples 1-9.
<Comparative Examples 1-3>
4-methyl-2-pentanol was added to 100 parts of each polymer (A) shown in Table 1 to obtain a solid content concentration of 1%, followed by filtration with a membrane filter having a pore size of 0.2 μm. The upper-layer antireflection film-forming composition of ~ 3 was obtained.

In addition, the detail of the component used for each Example and comparative example in Table 1 is shown below.
<Acid generator (B)>
(B-1): Triphenylsulfonium trifluoromethanesulfonate (B-2): Triphenylsulfonium nonafluorobutanesulfonate <Compound (C)>
(C-1): 5-sulfosalicylic acid (C-2): camphorsulfonic acid

[3] Measurement of refractive index The refractive index (wavelength 193 nm) of the film formed using each composition for forming an upper antireflection film in Examples and Comparative Examples was measured as follows. The results are also shown in Table 1.
<Measurement method of refractive index>
The composition for forming the upper antireflection film was spin-coated on a silicon wafer having a diameter of 8 inches so that the film thickness of the antireflection film formed was in the range of 26 to 33 nm. After that, J.H. A. Woollam Co. , Inc. The refractive index of the film was measured using an ellipsometer “VUV-VASE”.

[4] Performance evaluation About each composition for upper-layer antireflection film formation in an example and a comparative example, a resist pattern was formed and performance evaluation as an antireflection film was performed. The evaluation results are shown in Table 2.

(1) Formation of Resist Pattern After spin-coating a chemically amplified positive resist for ArF excimer laser (trade name “ARX1682J”, manufactured by JSR Corporation) on a silicon wafer having a diameter of 8 inches, a hot plate at 110 ° C. The photoresist film having a thickness of 0.19 μm was formed by pre-baking for 60 seconds.
Thereafter, the upper antireflection film-forming composition solutions of Examples and Comparative Examples were spin-coated on the photoresist film so that the thickness of the antireflection film to be formed was in the range of 26 to 33 nm. Next, using a scanner “NSRS306C” (wavelength: 193 nm) manufactured by Nikon Corporation, exposure was performed for a predetermined time. Immediately after the exposure, post exposure bake (PEB) was performed on a 115 ° C. hot plate for 60 seconds. Thereafter, development was performed at 25 ° C. for 1 minute using a 2.38% aqueous solution of tetramethylammonium hydroxide, washed with water, and dried to form a resist pattern.

(2) Performance evaluation of upper antireflection film <Developability>
The degree of scum and residual development due to the residue of the upper antireflection film or photoresist film was examined with a scanning electron microscope, and if no scum or residual development was observed, the developability was good.

<Pattern shape>
In the case of shapes (b), (c) and (d) among the cross-sectional shapes (a) to (f) shown in FIG. 1, the cross-sectional shape of the resist in the 160 nm-1L / 1S pattern is observed with a scanning electron microscope. Was good.

<Standing wave effect>
A photoresist film was formed on a silicon wafer having a diameter of 8 inches so that the film thickness was different by 0.01 μm in a range of 0.18 to 0.24 μm, and then an upper antireflection film was formed as described above. Next, exposure was performed by changing the exposure amount for each wafer using the reduced projection exposure machine. Thereafter, post-exposure baking and development were performed as described above to form a resist pattern.
Next, a wafer having a photoresist film thickness of 0.19 um was observed with a scanning electron microscope, and an exposure amount at which a 160 nm-1L / 1S pattern was obtained with a mask of 160 nm-1L / 1S was measured. Then, the wafer in each film thickness was observed with the obtained exposure amount, and the dimension of the pattern when the mask was 160 nm-1 L / 1S was measured. Then, the maximum value of the obtained pattern dimension is E _max , the minimum value is E _min , the S value of the following equation (the dimensional fluctuation accompanying the film thickness change) is used as an indicator of the standing wave effect, and the S value is smaller than 35 In some cases, the standing wave effect was good.
S = (E _max −E _min )

<Blob defect>
A chemical amplification type positive resist for ArF excimer laser (trade name “ARX1682J” manufactured by JSR Corporation) was spin-coated on an 8-inch diameter silicon wafer, and then pre-baked on a 110 ° C. hot plate for 60 seconds. A photoresist film having a thickness of 0.19 μm was formed.
Then, each antireflection film forming composition solution was spin-coated on the photoresist film so that the film thickness of each antireflection film to be formed was in the range of 26 to 33 nm. Next, using a scanner NSRS306C (wavelength: 193 nm) manufactured by Nikon Corporation, exposure for blob defect inspection was performed for a predetermined time, and immediately after exposure, baking was performed for 60 seconds on a 115 ° C. hot plate. Thereafter, development was performed at 25 ° C. for 1 minute using a 2.38% aqueous solution of tetramethylammonium hydroxide, washed with water, and dried to form a resist pattern.
Subsequently, defect measurement was performed with KLA2351 (KLA Tencor), and when the number of development peeling defects detected was 500 or less, it was judged good, and when it exceeded 500, it was deemed insufficient.

[5] Effects of Examples As can be seen from Table 2, when each of the upper antireflection film forming compositions of Examples 1 to 9 is used, the standing wave effect and blob defects can be sufficiently reduced. I was able to confirm that it was possible.

It is a schematic diagram explaining the cross-sectional shape of a pattern.

Claims (6)

A polymer (A) that is soluble in an alkali developer and has an aromatic group;
A composition for forming an upper antireflection film, comprising: at least one of a radiation sensitive acid generator (B) and a compound (C) having a sulfonic acid residue. The composition for forming an upper antireflection film according to claim 1, wherein the compound (C) having the sulfonic acid residue is a compound represented by the following formula (1).

[In the formula (1), R ¹ represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms or a derivative thereof, a hydroxyl group, a carboxyl group, an alkyl ether group. Represents an alkyloxycarbonyl group or an alkylcarbonyloxy group, and Z represents a linear, branched or alicyclic hydrocarbon group having 4 to 12 carbon atoms or an aromatic hydrocarbon which may have a substituent. Represents a group, m is an integer of 0 to 4, and n is an integer of 1 to 4. In the case where R ¹ there are a plurality, it may be the same or different from each other. ] The polymer (A) contains at least one of a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3), and measured by gel permeation chromatography. The composition for forming an upper antireflection film according to claim 1 or 2, wherein the weight average molecular weight is 1,000 to 100,000.

In [Equation ^(2), R 2 ~R ⁸ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ]

In [Equation ^{(3), R} 9 ~R ¹⁵ each represent a hydrogen atom, -OH, -COOH, or -SO ₃ H. ] The composition for forming an upper antireflection film according to claim 3, wherein the polymer (A) further contains at least one of repeating units represented by the following formulas (4) to (7).

[In the formula (4), R ¹⁶ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, A represents a single bond, a carbonyl group or a carbonyloxy group, and B represents a single bond or an imino group. , D represents a single bond, a linear, branched or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an aromatic hydrocarbon group which may have a substituent. ]

In [Equation (5), R ¹⁷ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group. ]

In [Equation ^{(6), R 18} represents a hydrogen atom, an alkyl group or fluorinated alkyl group having 1 to 12 carbon atoms having 1 to 12 carbon atoms. ]

[In the formula (7), R ¹⁹ represents a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, P represents a single bond, a carbonyl group or a carbonyloxy group, Q represents a single bond, 20 represents a linear, branched or alicyclic hydrocarbon group or an aromatic hydrocarbon group which may have a substituent, and R ²⁰ and R ²¹ each represent a hydrogen atom, a carbon number of 1 to 4 alkyl group or a C1-C4 fluorinated alkyl group is represented. ] The upper-layer antireflection film formation according to any one of claims 1 to 4, wherein the polymer (A) includes a repeating unit represented by the following formula (8) and a repeating unit represented by the following formula (9). Composition.

(1) forming a photoresist film on the substrate;
(2) using the composition for forming an upper antireflection film according to any one of claims 1 to 5 to form an upper antireflection film on the photoresist film;
(3) irradiating and exposing a desired region of the photoresist film on which the upper antireflection film is formed; and
(4) A step of developing to remove the upper antireflection film, and a resist pattern forming method.

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