JP2008203364A - Composition for resist underlayer film formation and resist underlayer film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for resist underlayer film formation capable of forming a resist underlayer film having a function as an antireflection film and also having good matching properties with a resist, and a resist underlayer film formed using the same. <P>SOLUTION: The composition for resist underlayer film formation contains a siloxane polymer component having specific repeating units. The resist underlayer film having a function as an antireflection film and also having good matching properties with a resist is obtained by forming a resist underlayer film using the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resist underlayer film forming composition used for forming a resist underlayer film that functions as an antireflection film when forming a resist pattern on a substrate, and a resist underlayer film formed using the same.

  Conventionally, in the manufacture of semiconductor devices, a lithography process has been used for pattern formation on a substrate. In recent years, with the high integration of semiconductor elements on a circuit board, pattern formation has been miniaturized. However, as the pattern becomes finer, the influence of standing waves generated in the exposure process increases, and there is a problem that it becomes difficult to transfer the pattern with accurate dimensions. Since a standing wave is generated by interference between incident light and reflected light from the substrate, one method for solving this problem is to provide an antireflection film (resist underlayer film, hard mask) under the resist layer. is there. The resist underlayer film is etched using the resist layer as a mask before pattern formation on the substrate.

  The resist underlayer film includes an organic type and an inorganic type. In the case of an organic resist underlayer film, since the resist layer is also organic, the etching rate is equivalent. Therefore, when the resist underlayer film is etched, the resist layer is similarly etched, and it becomes difficult to transfer an accurate pattern. On the other hand, it is conceivable that the resist layer is thickened to obtain necessary etching resistance. However, with the recent miniaturization of patterns, a pattern formed from a thick resist layer has a problem that pattern collapse tends to occur due to an increase in aspect ratio.

Therefore, an inorganic resist underlayer film has been studied. In the case of an inorganic resist underlayer film, the difference in etching speed with respect to the organic resist layer becomes large, and high etching selectivity can be obtained. Therefore, the pattern can be accurately transferred to the resist underlayer film even with a thin resist layer. Therefore, it is possible to solve the problem of pattern collapse by increasing the thickness of the resist layer. Here, Patent Documents 1 and 2 disclose those using a silicon-based material as an inorganic resist underlayer film.
JP 2004-310019 A JP-A-2005-18054

  However, in the resist underlayer films described in Patent Documents 1 and 2, good matching has not been obtained at the interface between the resist and the resist underlayer film. If the matching is poor, the resist pattern to be formed becomes an undercut shape and pattern collapse occurs, or it becomes difficult to transfer the exact dimensions to the substrate in a skirt shape. Therefore, a resist underlayer film forming composition capable of forming a resist underlayer film having good matching characteristics with a resist has been demanded.

The present invention has been made in view of the above problems. To provide a resist underlayer film forming composition capable of forming a resist underlayer film having a function as an antireflection film and having good matching characteristics with a resist, and a resist underlayer film formed using the resist underlayer film composition is there.
Here, “having good matching characteristics with the resist” means that the resist pattern formed on the resist underlayer film has neither an undercut shape nor a skirt shape, and is perpendicular to the resist underlayer film surface. This means that it has an excellent shape.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by a resist underlayer film forming composition containing a siloxane polymer component having a specific repeating unit. The present invention has been completed.

［式（１）と（２）の中で、Ｐｈはフェニル基を表す。Ａｒはナフチル基、アントラセン基、またはフェナントレン基を表す。Ｒ_１、Ｒ_２は、それぞれ独立して水素原子または１価の有機基を示す。また、複数のＲ_１同士、及びＲ_２同士が異なっていてもよい。ａ、ｂはそれぞれ０、１、または２である。］ More specifically, the present invention comprises a composition for forming a resist underlayer film comprising a siloxane polymer component having repeating units represented by the following general formulas (1) and (2), and the resist A resist underlayer film formed by applying a composition for forming an underlayer film and baking at a predetermined temperature is provided.

[In the formulas (1) and (2), Ph represents a phenyl group. Ar represents a naphthyl group, an anthracene group, or a phenanthrene group. R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent organic group. Moreover, several R < ₁ > and R < ₂ > may differ. a and b are 0, 1, or 2, respectively. ]

  According to the present invention, a resist underlayer film forming composition capable of forming a resist underlayer film having a function as an antireflection film and having good matching characteristics with a resist, and a resist underlayer formed using the same A membrane can be provided.

  Hereinafter, embodiments of the present invention will be described in detail. Although the composition for forming a resist underlayer film according to the present invention can be used at a wavelength of 248 nm or less, it is preferably described as being used with an ArF laser beam of 193 nm.

［式（１）と（２）の中で、Ｐｈはフェニル基を表す。Ａｒはナフチル基、アントラセン基、またはフェナントレン基を表す。Ｒ_１、Ｒ_２は、それぞれ独立して水素原子または１価の有機基を示す。また、複数のＲ_１同士、及びＲ_２同士が異なっていてもよい。ａ、ｂはそれぞれ０、１、または２である。］ The composition for forming a resist underlayer film according to the present invention contains a siloxane polymer component having a repeating unit represented by the following general formulas (1) and (2).

[In the formulas (1) and (2), Ph represents a phenyl group. Ar represents a naphthyl group, an anthracene group, or a phenanthrene group. R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent organic group. Moreover, several R < ₁ > and R < ₂ > may differ. a and b are 0, 1, or 2, respectively. ]

  Since the siloxane polymer component contains a repeating unit of formula (1) having a phenyl group and a repeating unit of formula (2) having a naphthyl group, an anthracene group, or a phenanthrene group, the siloxane polymer component has a function as an antireflection film. In addition, good matching characteristics with the resist can be obtained.

  More specifically, by having a phenyl group, a naphthyl group, an anthracene group, and a phenanthrene group, etching resistance to oxygen-based plasma can be improved when a resist underlayer film is formed. Furthermore, by having a phenyl group, light absorption with respect to a wavelength of 193 nm of an ArF laser can be improved. Further, by having a naphthyl group, an anthracene group, and a phenanthrene group, good matching with a resist can be obtained. Among these, a naphthyl group that can maximize the Si content of the siloxane polymer component is preferable. A high Si content means that the inorganic property of the resist underlayer film is increased, which is preferable because the etching selectivity with respect to the organic film can be increased.

  The proportion of the repeating unit of the formula (1) is in the range of 0.45 to 86 mol% with respect to the entire siloxane polymer component, and the proportion of the repeating unit of the formula (2) is 3.6 to 55 mol%. It is a range. When each structural unit is within this range, a resist underlayer film composition having a sufficient antireflection function and capable of forming a good pattern with high perpendicularity can be obtained.

  Preferably, the ratio of the repeating unit of formula (1) is in the range of 1 to 73 mol%, and the ratio of the repeating unit of formula (2) is in the range of 9 to 50 mol%. More preferably, the ratio of the repeating unit of formula (1) is in the range of 2 to 64 mol%, and the ratio of the repeating unit of formula (2) is in the range of 13 to 40 mol%.

In Formula (1), it is preferable that the values of a and b are 0 because a ladder skeleton can be formed and the curability of the resist underlayer film can be improved. Moreover, it is preferable because the Si content of the siloxane polymer component can be maintained high, the inorganic property of the resist underlayer film can be increased, and the etching selectivity with respect to the organic film can be increased. R ₁ and R ₂ are preferably hydrogen atoms because the Si content can be maintained high. Further, it is considered that the Si—H bond functions as a crosslinking site and can improve the curability of the film.

When R ₁ and R ₂ are monovalent organic groups, the effect of the present invention is not particularly limited as long as the effects of the present invention can be obtained. However, since Ph and Ar are bulky functional groups, for example, 1 to 5 carbon atoms. A sterically small substituent such as a linear / branched alkyl group, a hydroxyl group, or an alkoxy group having 1 to 4 carbon atoms is preferred. Among these, when R ₁ and R ₂ contain a hydroxyl group, if each of the repeating units represented by the formulas (1) and (2) is 40 mol% or less, It is preferable because gelation can be prevented. Moreover, it is preferable for the same reason that the repeating unit having a hydroxyl group is 40 mol% or less with respect to the entire siloxane polymer component.

  Moreover, as a monovalent organic group, the monovalent organic group which can be bridge | crosslinked can also be mentioned, for example. Examples of the monovalent organic group capable of crosslinking include an organic group containing an epoxy group or an oxetanyl group. The presence of a crosslinking group is preferable because the curability of the lower layer film can be increased.

［式（３）中、Ｍｅはメチル基を表す。Ｒ_３は独立して、水素原子、アルキル基、ヒドロキシル基、架橋可能な１価の有機基、または，ヒドロキシル基、ポリエーテル基、カルボニル基、エステル基、ラクトン基、アミド基、エーテル基、及びニトリル基よりなる群から選択される少なくとも１つの官能基を有する１価の有機基を表す。また、複数のＲ_３同士が異なっていてもよい。ｃは０、１、または２である。］ Moreover, it is preferable that the said siloxane polymer component further has a repeating unit represented by the following general formula (3).

[In formula (3), Me represents a methyl group. R ₃ is independently a hydrogen atom, an alkyl group, a hydroxyl group, a crosslinkable monovalent organic group, or a hydroxyl group, a polyether group, a carbonyl group, an ester group, a lactone group, an amide group, an ether group, and It represents a monovalent organic group having at least one functional group selected from the group consisting of nitrile groups. Or it may be different plurality of R ₃ to each other. c is 0, 1, or 2. ]

  The methyl group is preferable because it is an organic group that can maintain a high Si content next to a hydrogen atom. In addition, a resin composed of Si—H bonds has a property of easily dissolving in an alkali developer, whereas a resin composed of Si—Me bonds has a property of being hardly soluble in an alkali developer. Therefore, it is preferable that the siloxane polymer component contains the formula (3) because the alkali developer resistance of the resist underlayer film can be improved when the resist film is alkali-developed. By having sufficient resistance to alkali developer, it is possible to prevent the resist underlayer film from being damaged during development of the resist layer, and to make the pattern shape on the substrate obtained after etching good (rectangular).

In Formula (3), it is preferable that c is 0 because a ladder skeleton can be formed and the curability of the resist underlayer film can be improved. Moreover, it is preferable because the Si content of the siloxane polymer component can be maintained high, the inorganic property of the resist underlayer film can be increased, and the etching selectivity with respect to the organic film can be increased. R ₃ is preferably a hydrogen atom because the Si content can be kept high. Further, it is considered that the Si—H bond functions as a crosslinking site and can improve the curability of the film. The alkyl group of R ₃ is preferably a linear / branched alkyl group having 1 to 5 carbon atoms. It is preferable that R ₃ is a hydrogen atom, an alkyl group, or a hydroxyl group because a balance in synthesis between the structural units is easily achieved. It is preferable that R ₃ is a crosslinkable monovalent organic group since the curability of the lower layer film can be increased. Examples of the monovalent organic group capable of crosslinking include an organic group containing an epoxy group or an oxetanyl group.

R ₃ is a monovalent organic group having at least one functional group selected from the group consisting of a hydroxyl group, a polyether group, a carbonyl group, an ester group, a lactone group, an amide group, an ether group, and a nitrile group. It is preferable because the verticality of the resist pattern shape can be improved. When R ₃ contains a hydroxyl group, the composition for forming a resist underlayer film, when the proportion of the repeating unit in which R ₃ is a hydroxyl group in the entire repeating unit represented by the formula (3) is 40 mol% or less It is preferable because it can prevent gelation.

  The repeating unit of the formula (3) is preferably in the range of 7.2 to 91.5 mol% with respect to the total siloxane polymer component from the viewpoint of the Si content and the resistance to alkali developer. .

［式（４）中、Ｒ_３は上述の通りである。また、複数のＲ_３同士が異なっていてもよい。ｄは０、１、または２である。］ Moreover, it is preferable that the said siloxane polymer component further has a repeating unit represented by the following general formula (4).

[In the formula (4), R ₃ is as described above. Or it may be different plurality of R ₃ to each other. d is 0, 1, or 2. ]

  A repeating unit containing a hydrogen atom is preferable because it can maintain a high Si content in the siloxane polymer component, increase the inorganic properties of the resist underlayer film, and increase the etching selectivity with respect to the organic film. Further, it is considered that the Si—H bond functions as a crosslinking site and can improve the curability of the film.

In Formula (4), it is preferable that d is 0 because a ladder skeleton can be formed and the curability of the resist underlayer film can be improved. Moreover, since Si content rate can be maintained high, it is preferable. R ₃ is as described above, and when R ₃ contains a hydroxyl group, the proportion of the repeating unit in which R ₃ is a hydroxyl group in the whole repeating unit represented by the formula (4) is 40 mol% or less. This is preferable because gelation of the resist underlayer film composition can be prevented.

  It is preferable from the point of the above-mentioned Si content that the repeating unit of Formula (4) is in the range of 0.45 to 86 mol% with respect to the total siloxane polymer component.

［式（５）中、Ｒ_３は上述の通りである。Ｒは、エステル基及びポリエーテル基から選択される少なくとも１つの官能基を有する１価の有機基を表す。また、複数のＲ_３同士が異なっていてもよい。ｅは０、１、または２である。］ Moreover, it is preferable that the said siloxane polymer component further has a repeating unit represented by the following general formula (5).

[In the formula (5), R ₃ is as described above. R represents a monovalent organic group having at least one functional group selected from an ester group and a polyether group. Or it may be different plurality of R ₃ to each other. e is 0, 1 or 2; ]

［式（６）中、ａは２〜１２、ｂは２〜６、ｃは２〜２００であり、Ｒ’は水素原子、アルキル基、またはその他の有機基である。］ Having a repeating unit containing R is preferable because the resist underlayer film according to the present invention can improve the adhesion to the resist film. R is selected from an ester group and a polyether group. An ester group is an organic group containing at least one ester group. The polyether group has a structure as shown in the following formula (6).

[In Formula (6), a is 2-12, b is 2-6, c is 2-200, and R 'is a hydrogen atom, an alkyl group, or another organic group. ]

As the ester group, for example, those represented by the following formulas (7) and (8) are preferable.

As the polyether group, for example, those represented by the following formulas (9) to (11) are preferable.

In Formula (5), it is preferable that e is 0 because a ladder skeleton can be formed and the curability of the resist underlayer film can be improved. Moreover, it is preferable because the Si content of the siloxane polymer component can be maintained high, the inorganic property of the resist underlayer film can be increased, and the etching selectivity with respect to the organic film can be increased. R ₃ is as described above, and when R ₃ contains a hydroxyl group, the proportion of the repeating unit in which R ₃ is a hydroxyl group in the whole repeating unit represented by the formula (5) is 40 mol% or less. This is preferable because gelation of the resist underlayer film composition can be prevented.

  The repeating unit of the formula (5) is preferably in the range of 0.09 to 86 mol% with respect to the total siloxane polymer from the viewpoint of improving the above-mentioned adhesion.

  The mass average molecular weight of the siloxane polymer in the siloxane polymer component is preferably in the range of 300 to 400,000. By using the siloxane polymer in the above range, the film formability and coating property of the resist underlayer film forming composition can be improved. More preferably, it is 500-100,000.

  The siloxane polymer component is a mixture containing a siloxane polymer A having a repeating unit represented by the formula (1) and a siloxane polymer B having a repeating unit represented by the formula (2). It is preferable.

  By using the mixture of the siloxane polymers A and B, the composition for forming a resist underlayer film according to the present invention has a sufficient antireflection function for short wavelength exposure of 248 nm or less and a good matching characteristic with a resist film. It is preferable because a resist underlayer film can be formed and the adjustment of the siloxane polymer component can be simplified.

<Siloxane polymer A>
The siloxane polymer A has a repeating unit represented by the formula (1). When the ratio of the repeating unit of the formula (1) is in the range of 5 to 95 mol% with respect to the entire siloxane polymer A, the light absorption function is improved and the etching resistance to oxygen-based plasma when a resist underlayer film is formed. Can be improved. If it is in the range of 10 to 50 mol%, it can be balanced with other repeating units, which is more preferable.

  The siloxane polymer A preferably further has a repeating unit represented by the formula (3). The repeating unit of the formula (3) is preferably in the range of 5 to 95 mol% with respect to the entire siloxane polymer A from the viewpoint of the Si content and the resistance to alkali developer. If it is in the range of 10 to 70 mol%, it is possible to balance with other repeating units, which is more preferable.

  Moreover, it is preferable that the said siloxane polymer A further has a repeating unit represented by the said Formula (4). The repeating unit of the formula (4) is preferably in the range of 5 to 95 mol% with respect to the entire siloxane polymer A from the viewpoint of the Si content described above. If it is in the range of 10 to 70 mol%, it is possible to balance with other repeating units, which is more preferable.

  The siloxane polymer A preferably further has a repeating unit represented by the formula (5). The repeating unit of the formula (5) is preferably in the range of 1 to 95 mol% with respect to the entire siloxane polymer A from the viewpoint of improving the adhesion. If it is in the range of 5 to 20 mol%, it is possible to balance with other repeating units, which is more preferable.

［式（１２）中、Ｐｈ、Ｍｅ、Ｒ、Ｒ_１、Ｒ_３は、上述の通りである。複数のＲ_１同士、Ｒ_３同士が異なっていてもよい。ａ、ｃ、ｄ、ｅは０、１、または２である。］ The siloxane polymer A preferably includes a repeating unit represented by the following general formula (12).

[In the formula (12), Ph, Me, R, R ₁ and R ₃ are as described above. A plurality of R ₁ may be different from each other and R ₃ may be different from each other. a, c, d, and e are 0, 1, or 2. ]

  The range of m, s, t, u (unit: mol%) with respect to the entire siloxane polymer A is 5 to 95, s is 5 to 95, t is 5 to 95, u is 1 to 95, and m + s + t + u. = 100. Preferred ranges are m = 10-50, s = 10-70, t = 10-70, u = 5-20, m + s + t + u = 100, respectively.

  As the siloxane polymer A, for example, a, c, d, and e in the formula (12) are 0, and m, s, t, and u are m = 10 to 25, s = 15 to 30, and t = 25, respectively. -55, u = 5-20, and R is a substituent represented by Formula (7). Or, a, d, e, and f of formula (12), m, s, t, and u are as described above, and R is a substituent represented by formula (10). The siloxane polymer A having these structures is preferable because it is particularly excellent in the above-described antireflection function, etching resistance, Si content, alkali developer resistance, and improved adhesion.

  The siloxane polymer A preferably has a mass average molecular weight of 500 to 400,000. By setting the mass average molecular weight of the siloxane polymer A within the above range, the film formability and coating property of the resist underlayer film forming composition can be improved. More preferably, it is 500-100,000, More preferably, it is 700-10,000.

  The siloxane polymer A is obtained by hydrolyzing and condensation-polymerizing each monomer capable of deriving the repeating unit represented by the formulas (1) to (12). The amount of water during the hydrolysis reaction is preferably 0.2 to 10 moles per mole of monomer. As each monomer, alkoxysilanes or chlorosilanes capable of deriving each repeating unit are preferably used. In the condensation polymerization, a conventionally known catalyst such as a metal chelate compound, an organic acid, an inorganic acid, an organic base, or an inorganic base may be added as appropriate.

  Examples of the metal chelate compound include tetraalkoxytitanium, trialkoxymono (acetylacetonato) titanium, tetraalkoxyzirconium, trialkoxymono (acetylacetonato) zirconium, and the like. Examples of the organic acid include acetic acid, propionic acid, oleic acid, stearic acid, linoleic acid, salicylic acid, benzoic acid, formic acid, malonic acid, phthalic acid, fumaric acid, citric acid, and tartaric acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, sulfonic acid, methyl sulfonic acid, tosylic acid, trifluoromethane sulfonic acid, and the like. Organic bases include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, diazabicyclononane, diazine Examples include zabicycloundecene and tetramethylammonium hydroxide. Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.

  In the case where the repeating unit of the siloxane polymer contains a monovalent organic group that can be cross-linked as described above, ammonia, organic amines, etc., so that the cross-linking reaction does not proceed during polymerization and so that alkali and metal impurities are not mixed. It is preferable to use the basic catalyst. Of these, tetraalkylammonium hydroxide is preferably used. In addition, when an epoxy group or an oxetanyl group is included as a monovalent organic group that can be cross-linked, it is preferable to set the system in an atmosphere of pH 7 or higher in order to prevent ring opening of these groups. These catalysts can be used alone or in combination of two or more.

  As a reaction operation, first, each monomer is dissolved in an organic solvent, and water is added to start a hydrolysis reaction. The catalyst may be added to water or may be added to an organic solvent.

  As the organic solvent used in the reaction, those which are hardly soluble or insoluble in water are preferable. Specifically, tetrahydrofuran, toluene, hexane, ethyl acetate, cyclohexanone, methyl-2-n-amyl ketone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol Dimethyl ether and mixtures thereof are preferred.

  Next, the catalyst is neutralized and the organic solvent layer is separated and dehydrated. This is because the remaining water causes the condensation reaction of the remaining silanol to proceed. A known dehydration method such as an adsorption method using a salt such as magnesium sulfate or a molecular sieve, or an azeotropic dehydration method while removing the solvent is used.

  Subsequently, a slightly soluble or insoluble organic solvent is added to the water, and the organic solvent layer is separated and washed with water to remove the catalyst used for hydrolysis and condensation. At this time, you may neutralize as needed. Finally, the siloxane polymer A is obtained by dehydrating the separated organic solvent layer.

<Siloxane polymer B>
Siloxane polymer B has a repeating unit represented by the general formula (2). The repeating unit of the formula (2) is in the range of 40 to 60 mol% with respect to the entire siloxane polymer B, and the above-described improvement in etching resistance to oxygen-based plasma when used as a resist underlayer film, and resist It is preferable because good matching with can be obtained. It is more preferable in the range of 45 to 55 mol%.

  The siloxane polymer B preferably further has a repeating unit represented by the formula (3). The repeating unit of the formula (3) is preferably in the range of 30 to 60 mol% with respect to the entire siloxane polymer B from the above-mentioned point of Si content and alkali developer resistance. More preferably, it is in the range of 45 to 55 mol%.

  Moreover, it is preferable from the point of the simplicity at the time of synthesize | combining the siloxane polymer B that the said siloxane polymer B consists of a repeating unit represented by the said General formula (2) and (3). When the ratio of the repeating units of the formulas (2) and (3) is in the range of 40 to 60 mol% with respect to the entire siloxane polymer B, the above-mentioned etching resistance and good matching with the resist From the standpoint of maintaining the Si content and improving the resistance to alkali developer. It is more preferable in the range of 45 to 55 mol%.

  Similar to the siloxane polymer A, the siloxane polymer B is obtained by hydrolyzing and polycondensing each monomer capable of deriving the repeating unit represented by the above formulas (2) and (3). The specific manufacturing method is as described above.

  The mass average molecular weight of the siloxane polymer B is preferably 300 to 8,000. By setting the mass average molecular weight of the siloxane polymer B within the above range, the compatibility with the siloxane polymer A is improved, and a more dense resist underlayer film can be formed. More preferably, it is 500-1500.

  The content of the siloxane polymer B is 10 parts by mass to 1,000 parts by mass with respect to 100 parts by mass of the siloxane polymer A. By setting the content of the siloxane polymer B within the above range, it is possible to form a resist underlayer film having a sufficient antireflection function and good matching characteristics with the resist film. Preferably, they are 30 mass parts-500 mass parts, More preferably, they are 50 mass parts-200 mass parts.

<Solvent>
The composition for forming a resist underlayer film according to the present invention may contain a solvent. The kind of solvent is not specifically limited, A conventionally well-known solvent can be used. Specifically, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, hexanetriol, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopro Alcohol monoethers such as ether, propylene glycol monobutyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate and ethyl lactate (EL), ketones such as acetone, methyl ethyl ketone, cycloalkyl ketone, methyl isoamyl ketone, ethylene Glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether (PGDM), propylene glycol diethyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and other alcohols All hydroxyl groups of Alcohol ethers obtained by ether reduction, glycol ether esters such as propylene glycol monomethyl ether acetate (PGMEA) and the like.

  The said solvent may be used independently and may be used in combination of 2 or more type. The amount of the solvent used is preferably 1 to 100 times the mass of the siloxane polymer component. By making the total use amount of the solvent within this range, the applicability of the resist underlayer film forming composition can be improved. More preferably, the amount is 2 to 20 times.

<Crosslinking agent>
The composition for forming a resist underlayer film according to the present invention may contain a crosslinking agent. By including a crosslinking agent, the film formability of the resist underlayer film can be further improved. It does not specifically limit as a kind of crosslinking agent, A conventionally well-known crosslinking agent can be used. Specific examples include epoxy compounds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, and cresol novolak type epoxy resin. Further, divinylbenzene, divinylsulfone, triacryl formal, glyoxal, polyhydric alcohol acrylic ester or methacrylic ester or the like can also be used. Furthermore, compounds having two or more reactive groups in which at least two amino groups of melamine, urea, benzoguanamine, and glycoluril are substituted with a methylol group or a lower alkoxymethyl group can be used.

  Compounds in which at least two amino groups of melamine are substituted with a methylol group or a lower alkoxymethyl group include compounds in which 1 to 6 of hexamethylol melamine, hexamethoxymethyl melamine, hexamethylol melamine are methoxymethylated, and Examples thereof include a mixture, a compound in which one to five methylol groups of hexamethoxyethylmelamine, hexaacyloxymethylmelamine, and hexamethylolmelamine are acyloxymethylated, or a mixture thereof.

  Examples of the compound in which at least two amino groups of urea are substituted with a methylol group or a lower alkoxymethyl group include 1 to 4 methylol groups of tetramethylol urea, tetramethoxymethyl urea, tetramethoxyethyl urea, and tetramethylol urea. Examples thereof include a methoxymethyl group compound or a mixture thereof.

  As a compound in which at least two amino groups of benzoguanamine are substituted with a methylol group or a lower alkoxymethyl group, 1 to 4 methylol groups of tetramethylolguanamine, tetramethoxymethylguanamine, and tetramethylolguanamine are methoxymethylated. Examples thereof include a compound or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethoxyethylguanamine, tetraacyloxyguanamine, and tetramethylolguanamine are acyloxymethylated, or a mixture thereof.

  Examples of the compound in which at least two of the amino groups of glycoluril are substituted with a methylol group or a lower alkoxymethyl group include one of the methylol groups of tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril and tetramethylolglycoluril. -4 compounds having a methoxymethyl group or a mixture thereof, compounds having 1 to 4 methylol groups in tetramethylol glycoluril, or a mixture thereof.

  The said crosslinking agent may be used independently and may be used in combination of 2 or more type. As a usage-amount of a crosslinking agent, 0.1 mass part-50 mass parts are preferable with respect to 100 mass parts of siloxane polymer components. More preferably, it is 0.5 mass part-40 mass parts.

<Acid generator>
The resist underlayer film forming composition according to the present invention may contain an acid generator. It does not specifically limit as a kind of acid generator, A conventionally well-known acid generator can be used. Specifically, onium salts, diazomethane derivatives, glyoxime derivatives, bissulfone derivatives, β-ketosulfone derivatives, disulfone derivatives, nitrobenzyl sulfonate derivatives, sulfonate ester derivatives, sulfonate ester derivatives of N-hydroxyimide compounds, and the like can be used. it can.

Examples of onium salts include tetramethylammonium trifluoromethanesulfonate, tetramethylammonium nonafluorobutanesulfonate, tetra-n-butylammonium nonafluorobutanesulfonate, tetraphenylammonium nonafluorobutanesulfonate, and tetramethyl p-toluenesulfonate. Ammonium, trifluoromethanesulfonic acid diphenyliodonium, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, p-toluenesulfonic acid diphenyliodonium, p-toluenesulfonic acid (p-tert-butoxyphenyl) phenyliodonium, trifluoromethane Triphenylsulfonium sulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) Phenylsulfonium, trifluoromethanesulfonic acid bis (p-tert-butoxyphenyl) phenylsulfonium, trifluoromethanesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, p-toluenesulfonic acid triphenylsulfonium, p-toluenesulfonic acid (p -Tert-butoxyphenyl) diphenylsulfonium, bis (p-tert-butoxyphenyl) phenylsulfonium p-toluenesulfonate, tris (p-tert-butoxyphenyl) sulfonium p-toluenesulfonate, triphenylsulfonium nonafluorobutanesulfonate , Triphenylsulfonium butanesulfonate, trimethylsulfonium trifluoromethanesulfonate, trimethylsulfone p-toluenesulfonate , Cyclohexylmethyl trifluoromethanesulfonate (2-oxocyclohexyl) sulfonium, p-toluenesulfonate cyclohexylmethyl (2-oxocyclohexyl) sulfonium, trifluoromethanesulfonate dimethylphenylsulfonium, p-toluenesulfonate dimethylphenylsulfonium, trifluoromethane Dicyclohexylphenylsulfonium sulfonate, dicyclohexylphenylsulfonium p-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, (2-norbornyl) methyl trifluoromethanesulfonate (2- Oxocyclohexyl) sulfonium, ethylenebis [Methyl (2-oxocyclopentyl) sulfonium trifluoromethanesulfonate], 1,2'-naphthylcarbonylmethyltetrahydrothiophenium triflate and the like. Moreover, the thing of the following structural formula is mentioned preferably.

  Diazomethane derivatives include bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (xylenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (cyclopentylsulfonyl) diazomethane, bis (n-butylsulfonyl) diazomethane Bis (isobutylsulfonyl) diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane, bis (n-amylsulfonyl) diazomethane Bis (isoamylsulfonyl) diazomethane, bis (sec-amylsulfonyl) diazomethane, bis (tert-amylsulfur) Nyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-butylsulfonyl) diazomethane, 1-cyclohexylsulfonyl-1- (tert-amylsulfonyl) diazomethane, 1-tert-amylsulfonyl-1- (tert-butylsulfonyl) diazomethane Etc.

  Examples of glyoxime derivatives include bis-O- (p-toluenesulfonyl) -α-dimethylglyoxime, bis-O- (p-toluenesulfonyl) -α-diphenylglyoxime, bis-O- (p-toluenesulfonyl)- α-dicyclohexylglyoxime, bis-O- (p-toluenesulfonyl) -2,3-pentanedione glyoxime, bis-O- (p-toluenesulfonyl) -2-methyl-3,4-pentanedione glyoxime, Bis-O- (n-butanesulfonyl) -α-dimethylglyoxime, bis-O- (n-butanesulfonyl) -α-diphenylglyoxime, bis-O- (n-butanesulfonyl) -α-dicyclohexylglyoxime Bis-O- (n-butanesulfonyl) -2,3-pentanedione glyoxime, bis-O- ( -Butanesulfonyl) -2-methyl-3,4-pentanedione glyoxime, bis-O- (methanesulfonyl) -α-dimethylglyoxime, bis-O- (trifluoromethanesulfonyl) -α-dimethylglyoxime, bis -O- (1,1,1-trifluoroethanesulfonyl) -α-dimethylglyoxime, bis-O- (tert-butanesulfonyl) -α-dimethylglyoxime, bis-O- (perfluorooctanesulfonyl)- α-dimethylglyoxime, bis-O- (cyclohexanesulfonyl) -α-dimethylglyoxime, bis-O- (benzenesulfonyl) -α-dimethylglyoxime, bis-O- (p-fluorobenzenesulfonyl) -α- Dimethylglyoxime, bis-O- (p-tert-butylbenzenesulfonyl) α- dimethylglyoxime, bis -O- (xylene sulfonyl)-.alpha.-dimethylglyoxime, bis -O- (camphorsulfonyl)-.alpha.-dimethylglyoxime, and the like.

  Examples of bissulfone derivatives include bisnaphthylsulfonylmethane, bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane, bisethylsulfonylmethane, bispropylsulfonylmethane, bisisopropylsulfonylmethane, bis-p-toluenesulfonylmethane, and bisbenzenesulfonylmethane. Can be mentioned.

  Examples of the β-ketosulfone derivative include 2-cyclohexylcarbonyl-2- (p-toluenesulfonyl) propane and 2-isopropylcarbonyl-2- (p-toluenesulfonyl) propane.

  Examples of disulfone derivatives include disulfone derivatives such as diphenyl disulfone derivatives and dicyclohexyl disulfone derivatives.

  Examples of the nitrobenzyl sulfonate derivative include nitrobenzyl sulfonate derivatives such as p-toluenesulfonic acid 2,6-dinitrobenzyl and p-toluenesulfonic acid 2,4-dinitrobenzyl.

  Examples of sulfonic acid ester derivatives include 1,2,3-tris (methanesulfonyloxy) benzene, 1,2,3-tris (trifluoromethanesulfonyloxy) benzene, 1,2,3-tris (p-toluenesulfonyloxy). And sulfonic acid ester derivatives such as benzene.

  Examples of sulfonic acid ester derivatives of N-hydroxyimide compounds include N-hydroxysuccinimide methanesulfonic acid ester, N-hydroxysuccinimide trifluoromethanesulfonic acid ester, N-hydroxysuccinimide ethanesulfonic acid ester, N-hydroxysuccinimide 1-propanesulfonic acid. Ester, N-hydroxysuccinimide 2-propanesulfonic acid ester, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide 1-octanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxysuccinimide p-methoxybenzenesulfonic acid ester, N-hydroxysuccinimide 2-chloroethanesulfonic acid ester N-hydroxysuccinimide benzenesulfonic acid ester, N-hydroxysuccinimide 2,4,6-trimethylbenzenesulfonic acid ester, N-hydroxysuccinimide 1-naphthalenesulfonic acid ester, N-hydroxysuccinimide 2-naphthalenesulfonic acid ester, N-hydroxy 2-Phenylsuccinimide methanesulfonate, N-hydroxymaleimide methanesulfonate, N-hydroxymaleimide ethanesulfonate, N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimide methanesulfonate N-hydroxyglutarimide benzene sulfonate, N-hydroxyphthalimide methane sulfonate, N-hydroxy Phthalimidobenzenesulfonic acid ester, N-hydroxyphthalimide trifluoromethanesulfonic acid ester, N-hydroxyphthalimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, N-hydroxy -5-norbornene-2,3-dicarboximide methanesulfonate, N-hydroxy-5-norbornene-2,3-dicarboximide trifluoromethanesulfonate, N-hydroxy-5-norbornene-2,3- Dicarboximide p-toluenesulfonic acid ester etc. are mentioned.

  The said acid generator may be used independently and may be used in combination of 2 or more type. As the usage-amount of an acid generator, 0.1 mass part-50 mass parts are preferable with respect to 100 mass parts of siloxane polymer components. By setting the total amount of the acid generator to be used within this range, a resist pattern with good perpendicularity can be formed. More preferably, it is 0.5 mass part-40 mass parts.

［式（１３）中、Ｒａ〜Ｒｄは、それぞれ独立して炭化水素基であり、Ｘ⁻はカウンターアニオンである。］ <Quaternary ammonium compound>
The resist underlayer film forming composition according to the present invention preferably further contains a quaternary ammonium compound. When a quaternary ammonium compound is blended, it is possible to prevent the resist layer formed on the resist underlayer film from being reduced, and the shape of the resist pattern to be formed is preferable. Specifically, the quaternary ammonium compound is preferably a quaternary ammonium compound represented by the following general formula (13).

[In the formula (13), Ra to Rd are each independently a hydrocarbon group, and X ⁻ is a counter anion. ]

  Examples of the “hydrocarbon group” of Ra to Rd include linear, branched, or cyclic saturated or unsaturated hydrocarbon groups. These may have a substituent. Examples of linear and branched hydrocarbon groups include methyl, methylene, ethyl, ethylene, propyl, propylene, isopropyl, n-butyl, isobutyl, isopropylene and sec-butyl. Group, tertiary butyl group, amyl group, isoamyl group, tertiary amyl group, hexyl group, heptyl group, octyl group, isooctyl group, 2-ethylhexyl group, tertiary octyl group, nonyl group, isononyl group, decyl group, isodecyl Groups and the like.

  Examples of the cyclic hydrocarbon group include a cyclic alkyl group and an aryl group. Examples of the cyclic alkyl group include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as cycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Examples of the aryl group include a phenyl group, a naphthyl group, a methylphenyl group, an ethylphenyl group, a tolyl group, a chlorophenyl group, a bromophenyl group, and a fluorophenyl group.

  Moreover, as said substituent, OH group, a C1-C3 alkoxy group, etc. are mentioned, for example.

  Especially, the thing whose total carbon number of Ra-Rd is 10 or more is preferable. By setting the total number of carbon atoms to 10 or more as described above, tailing of the resist pattern formed on the resist underlayer film can be reduced and the pattern shape can be improved. Moreover, it is preferable that at least one of Ra to Rd is a hydrocarbon group having 8 or more carbon atoms. Thereby, the tailing of the resist pattern formed on the resist underlayer film can be further reduced. The total number of carbon atoms of Ra to Rd is preferably 25 or less. Thereby, skirting can be further reduced.

X ⁻ of the counter anion is preferably OH ⁻ , Cl ⁻ , Br ⁻ , F ⁻ , an alkyl carboxylate anion, an aryl carboxylate anion, an aralkyl carboxylate anion, or the like.

  Moreover, the addition amount of a quaternary ammonium compound is 0.01 mass part-10 mass parts with respect to 100 mass parts of siloxane polymer components, and prevents the film loss of the resist layer formed on a resist underlayer film. And the shape of the resist pattern to be formed is also preferable. It is more preferably 0.1 parts by mass to 5 parts by mass, and most preferably 0.1 parts by mass to 3 parts by mass.

<Organic acid>
The composition for forming a resist underlayer film according to the present invention preferably further contains an organic acid. By adding this organic acid, it is possible to prevent the deterioration of the resist underlayer film forming composition over time due to the addition of the quaternary ammonium compound.

  Examples of organic acids include organic carboxylic acids, organic phosphonic acids, and organic sulfonic acids. Examples of the organic carboxylic acid include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lauric acid, palmitic acid and stearic acid; unsaturated aliphatic monocarboxylic acids such as oleic acid and linoleic acid; oxalic acid, Aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid and maleic acid; oxycarboxylic acids such as lactic acid, gluconic acid, malic acid, tartaric acid and citric acid; aromatics such as benzoic acid, mandelic acid, salicylic acid and phthalic acid Carboxylic acids are mentioned. As these organic acids, malonic acid is particularly preferable.

  Moreover, it is preferable that the addition amount of an organic acid is 0.01 mass part-10 mass parts with respect to 100 mass parts of siloxane polymer components. By making the addition amount 0.01 parts by mass or more, the temporal stability of the resist underlayer film forming composition can be further improved. Moreover, the inhibition with respect to the said quaternary ammonium component can be suppressed by making addition amount into 10 mass parts or less.

  The mass ratio of the organic acid component and the quaternary ammonium compound is preferably in the range of 100: 20 to 100: 60, and more preferably in the range of 100: 30 to 100: 50. By making this mass ratio range, the tailing of the resist pattern formed on the resist underlayer film is reduced, the pattern shape is improved, and the temporal stability of the resist underlayer film composition is further improved. Can do.

  The composition for forming a resist underlayer film according to the present invention can be obtained by mixing the siloxane polymer component with the above-described solvent, crosslinking agent, acid generator, quaternary ammonium compound, organic acid, and the like as necessary. The obtained resist underlayer film forming composition is preferably filtered with a filter or the like.

<Resist underlayer film>
The resist underlayer film according to the present invention is formed by using the resist underlayer film forming composition. Specifically, the resist underlayer film forming composition is applied onto a workpiece such as a substrate (preferably, on an organic bottom layer formed on the substrate) using a spin coater, a slit nozzle coater, or the like. And then dried by heating. For the heating, a one-step heating method or a multi-step heating method is adopted. As a multistage heating method, for example, it is preferable to heat at 100 ° C. to 120 ° C. for 60 seconds to 120 seconds, and then at 200 ° C. to 250 ° C. for 60 seconds to 120 seconds. The thickness of the resist underlayer film according to the present invention thus formed is preferably 15 nm to 200 nm.

  The resist underlayer film according to the present invention is preferably used as an intermediate layer of a multilayer resist process such as a three-layer resist process. An example of a pattern forming method using the resist underlayer film according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1A, a conventionally known organic bottom layer forming composition is applied onto a substrate 20 by spin coating or the like, and baked at a predetermined temperature to form an organic bottom layer 26. Next, a resist underlayer film forming composition according to the present invention is applied onto the organic bottom layer 26 by a spin coat method or the like, and baked at a predetermined temperature to form a resist underlayer film 22. Next, a conventionally known resist composition is applied by spin coating or the like in the same manner as described above, and pre-baked at a predetermined temperature (preferably, at 150 to 300 ° C. for 30 to 300 seconds), and the resist film 24 ( Preferably, the film thickness is 100 nm to 300 nm.

Next, as shown in FIG. 1B, a predetermined pattern is formed by exposure and development. The resist underlayer film 22 is etched using the patterned resist film 24 as a mask, and the resist pattern is transferred to the resist underlayer film 22 as shown in FIG. Examples of the etching gas at this time include CF (CF _{4 and the} like), Cl (CCl _{4 and the} like), SF (SF _{6 and the} like), and the like. Further, FIG. 1D shows that the organic bottom layer 26 is etched using the resist film 24 and the resist underlayer film 22 as a mask, and the resist pattern is transferred to the organic bottom layer 26. As an etching gas at this time, an O ₂ system (O ₂ / N ₂ or the like) can be used. In the etching, the resist film 24 may be removed at the same time. Finally, FIG. 1E shows a pattern transferred to the substrate 20 using the resist underlayer film 22 and the organic bottom layer 26 as a mask. Examples of the etching gas at this time include CF (CF _{4 and the} like), CHF (CHF _{3 and the} like), Cl (CCl _{4 and the} like), SF (SF _{6 and the} like), and the like. In the etching, the resist underlayer film 22 may also be removed by etching at the same time.

  Since the organic bottom layer 26 acts as a mask when the substrate 20 is etched, it is desirable that the organic bottom layer 26 has high etching resistance. Further, since it is required not to mix with the upper resist lower layer film 22, it is desirable to crosslink with heat or acid after coating by spin coating or the like. Specifically, it is preferable to use a resin such as cresol novolak, naphthol novolak, catol dicyclopentadiene novolak, amorphous carbon, polyhydroxystyrene, (meth) acrylate, polyimide, polysulfone.

  Moreover, as a resist composition used for formation of the resist film 24, a conventionally well-known thing like the mixture of base resin, an organic solvent, and an acid generator can be used, for example. Base resins include polyhydroxystyrene and derivatives thereof, polyacrylic acid and derivatives thereof, polymethacrylic acid and derivatives thereof, copolymers selected from hydroxystyrene, acrylic acid, methacrylic acid and derivatives thereof, cycloolefin and derivatives thereof. Examples thereof include at least one polymer selected from the group consisting of a derivative, maleimide, acrylic acid and three or more copolymers selected from acrylic acid and derivatives thereof, polynorbornene, and a metathesis ring-opening polymer. The derivatives referred to here are those in which the main skeleton remains after induction so that acrylic acid derivatives include acrylic acid esters, methacrylic acid derivatives include methacrylic acid esters, etc., and hydroxystyrene derivatives include alkoxystyrene. Means what

  Further, as a resist composition for KrF excimer laser, co-polymerization of any one of polyhydroxystyrene, hydroxystyrene, and styrene with any one of acrylic acid ester, methacrylic acid ester, and maleimide N carboxylic acid ester Coalescence is mentioned. Also, as resist compositions for ArF excimer laser, acrylic ester, methacrylic ester, alternating copolymer of norbornene and maleic anhydride, alternating copolymer of tetracyclododecene and maleic anhydride, Examples thereof include polynorbornene and metathesis polymerization by ring-opening polymerization, but are not limited to these polymerization polymers.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

［式（１４）中、Ｒは、−（ＣＨ_２）_２−ＯＣ（Ｏ）Ｍｅであり、Ｍｅはメチル基を示す。カッコの外にある数字の単位はモル％である。］ <Example 1>
[Siloxane Polymer A]
In this example, a siloxane polymer having a repeating unit represented by the following formula (14) was used.

[In the formula (14), R represents — (CH ₂ ) ₂ —OC (O) Me, and Me represents a methyl group. The unit of the numbers outside the parentheses is mol%. ]

  Specifically, the siloxane polymer A was synthesized according to the following procedure. 120 g of PGMEA, 13.2 g (0.0625 mol) of phenyltrichlorosilane, 10.2 g (0.075 mol) of trichlorosilane, 14.9 g (0.1 mol) of methyltrichlorosilane, acetoxyethyltrichlorosilane 2.8 g (0.0125 mol) was added and mixed, and the mixture was reacted by nitrogenation. After the reaction, a mixed solution of 200 g of PGMEA and 10 g (0.555 mol) of water was added to the solution over 1 hour. The mixture was further stirred at 20 ° C. for 1 hour. The resin solution was concentrated to about 10 wt% by a rotary evaporator set at 40 ° C. About 40 g of ethanol was added to the resin solution. Again, the solution was stripped to about 20 wt%. Further, the reaction vessel was changed, and PGMEA was added to dilute to 10 wt%. The solution was filtered through a 0.2 micron PTFE filter. Siloxane polymer A was obtained through the above steps. When the molecular weight of the siloxane polymer A was determined by GPC, the mass average molecular weight (Mw) in terms of polystyrene was 9,700.

［式（８）中、Ｍｅはメチル基を示す。カッコの外にある数字の単位はモル％である。］ [Siloxane polymer B]
In this example, a siloxane polymer represented by the following formula (15) was used as the siloxane polymer B.

[In the formula (8), Me represents a methyl group. The unit of the numbers outside the parentheses is mol%. ]

Specifically, the siloxane polymer B was synthesized according to the following procedure. A 1L four-necked flask was charged with 97.1 g (5.39 mol) of water and 9.1 g of 35% aqueous hydrochloric acid, 108.5 g (0.437 mol) of 1-naphthyltrimethoxysilane and 59.5 g of methyltrimethoxysilane. (0.437 mol) of 252.2 g of toluene was added dropwise at a reaction temperature of 10 to 20 ° C. After completion of the dropwise addition, after aging for 2 hours at the same temperature, it was confirmed by GC analysis of the reaction solution that all the raw materials were gone. Next, liquid separation was performed after standing, and an oil layer was recovered. Subsequently, it was washed with a 5% aqueous sodium hydrogen carbonate solution, further washed with water, and finally a toluene oil layer was recovered. The solvent was removed from the obtained oil layer with an evaporator to obtain 117.2 g of a white powder of 1-naphthylsilsesquioxane / methylsilsesquioxane copolymer. As a result of GPC analysis, Mw was 1,000 and dispersity (Mw / Mn: polystyrene conversion) was 1.2. Moreover, the spectrum data of the obtained siloxane polymer B are shown below.
Infrared absorption spectrum (IR) data: 3055, 1504 cm ⁻¹ (naphthalene), 1026-1111 cm ⁻¹ (Si—O) (Shimadzu IR Prestige-21).
Nuclear magnetic resonance spectrum (NMR) data: 0.182 ppm (bs), 7.021-8.252 ppm (b) ( ¹ H-NMR solvent: CDCl ₃ , 400 MHz NMR measuring instrument manufactured by JEOL Ltd.).

[Preparation of resist underlayer film forming composition]
50 parts by mass of siloxane polymer A, 50 parts by mass of siloxane polymer B, 0.3 parts by mass of hexadecyltrimethylammonium acetate, 0.75 parts by mass of malonic acid, and PGMEA / EL = 6/4 as a solvent The siloxane polymer A and the siloxane polymer B were added so as to adjust the polymer solid content concentration to 2.5% by mass.

  The Si concentration in the solid content in the resist underlayer film forming composition of this example was 29.4% by mass (calculated from the formulation). This value can be regarded as equivalent to the Si concentration in the resist underlayer film to be formed. The resist underlayer film formed using this resist underlayer film forming composition has a refractive index (n value) at 193 nm of 1.50, an extinction coefficient (k value) of 0.15 and a refractive index at 248 nm (n Value) was 1.66, and the extinction coefficient (k value) was 0.034.

[Adjustment of organic bottom layer forming composition]
As the organic bottom layer forming composition, two types of bottom layer A and bottom layer B were used. As the bottom layer A, 100 parts by mass of the polymer (Mw: 6,000) represented by the following formula (16), 20 parts by mass of Sanwa Chemical's binder “Nikarak MX270” (trade name), and Nippon Cytec's addition 1 part by weight of the agent “Catalyst 602” (trade name) and 0.05 part by weight of the surfactant “Megafac XR104” (trade name) manufactured by Dainippon Ink & Chemicals, Inc., and the solvent PGMEA / EL = 6 / 4 was prepared and added so that the solid content concentration was 14.3% by mass.

As the bottom layer B, 100 parts by mass of the polymer represented by the following formula (17) (Mw: 8,700), 20 parts by mass of Sanwa Chemical's binder “Nikarak MX270” (trade name), Nippon Cytec's addition 1 part by weight of the agent “Catalyst 602” (trade name) and 0.05 part by weight of the surfactant “Megafac XR104” (trade name) manufactured by Dainippon Ink & Chemicals, Inc., and the solvent PGMEA / EL = 6 / 4 was prepared and added so that the solid content concentration was 12.5% by mass.

[Pattern formation]
An organic bottom layer was formed by applying a composition for forming an organic bottom layer on a silicon wafer using a conventional resist coater and performing a heat treatment at 250 ° C. for 90 seconds. In the case of the bottom layer A, the film thickness was 300 nm, and in the case of the bottom layer B, the film thickness was 250 nm.

  Next, the resist underlayer film forming composition was applied on these organic bottom layers, and a heat treatment was performed at 250 ° C. for 90 seconds to form a resist underlayer film. The resist underlayer film formed on the bottom layer A was 60 nm thick, and the resist underlayer film formed on the bottom layer B was 50 nm thick. Further, a resist composition was formed on these resist underlayer films to form a resist film, and exposure and development with an ArF excimer laser were performed. Here, the shape of the resist pattern formed by development was evaluated.

  In addition, as resist composition, pattern formation was performed using three types of resist A, resist B, and resist C, respectively. When the organic bottom layer is the bottom layer A, pattern formation using the resist A is performed in Example 1-1, pattern formation using the resist B is performed in Example 1-2, and pattern formation using the resist C is performed. It was set as Example 1-3. Further, pattern formation using the resist C on the bottom layer B was taken as Example 1-4.

Example 1-1 As the resist A, 50 parts by mass of a polymer I (Mw: 7,000) having a repeating unit represented by the following formula (18), a repeating unit represented by the following formula (19) 50 parts by mass of polymer II having a molecular weight (Mw: 10,000), 4.0 parts by mass of an acid generator represented by the following formula (20), and 1. an acid generator represented by the following formula (21). 0 parts by mass, 4.0 parts by mass of an acid generator represented by the following formula (22), 1.0 part by mass of a quencher tri-n-octylamine, 10 parts by mass of γ-butyrolactone as an additive, Similarly, 0.39 parts by mass of the additive salicylic acid was mixed, and the solvent PGMEA / EL = 6/4 was prepared and added so that the solid content concentration was 5.6% by mass. Further, this resist A was applied to form a resist film having a thickness of 130 nm, and a 120 nm line and space (L / S) pattern was formed.

Example 1-2 As the resist B, 100 parts by mass of polymer III (Mw: 7,000) having a repeating unit represented by the following formula (23), acid generation represented by the above formula (21) 8.0 parts by weight of the agent, 1.2 parts by weight of the quencher tri-n-pentylamine, 0.10 parts by weight of the surfactant “Megafac XR104” (trade name) manufactured by Dainippon Ink & Chemicals, 10 parts by weight of γ-butyrolactone as an additive and 1.32 parts by weight of salicylic acid as an additive are mixed, and PGMEA / EL = 6/4 as a solvent is set so that the polymer solid content concentration is 5.0% by weight. What was prepared and added was used. Further, this resist B was applied to form a resist film having a thickness of 100 nm, and an L / S pattern having a thickness of 50 nm was formed.

Example 1-3 As the resist C, 100 parts by mass of polymer IV (Mw: 10,000) having a repeating unit represented by the following formula (24), acid generation represented by the above formula (20) 13.0 parts by weight of the agent, 0.54 parts by weight of the quencher tri-n-pentylamine, 0.10 parts by weight of the surfactant “Megafac XR104” (trade name) manufactured by Dainippon Ink & Chemicals, 10 parts by mass of γ-butyrolactone as an additive and 1.32 parts by mass of salicylic acid as an additive were mixed, and PGMEA / EL = 6/4 as a solvent was adjusted so that the polymer solid content concentration was 6.3% by mass. What was prepared and added was used. Further, this resist C was applied to form a resist film having a thickness of 160 nm, and an L / S pattern having a thickness of 120 nm was formed.

(Example 1-4)
The resist C described above was applied to form a resist film having a thickness of 120 nm, and an L / S pattern having a thickness of 90 nm was formed.

<Example 2>
[Siloxane Polymer A]
In this example, the same siloxane polymer as in Example 1 was used.

［式（２５）中、Ｍｅはメチル基を示す。カッコの外にある数字の単位はモル％である。ノルボルナン骨格をもつ構成単位について、Ｓｉ−との結合位置は、２位と３位にあるものが混在している。］ [Siloxane polymer B]
In this example, a siloxane polymer represented by the following formula (25) was used as the siloxane polymer B.

[In the formula (25), Me represents a methyl group. The unit of the numbers outside the parentheses is mol%. Regarding the structural unit having a norbornane skeleton, the bonding positions with Si- are mixed at the 2nd and 3rd positions. ]

Specifically, the siloxane polymer B was synthesized according to the following procedure. In a 1 L four-necked flask, 97.1 g (5.39 mol) of water and 9.1 g of 35% hydrochloric acid aqueous solution were charged, 108.5 g (0.437 mol) of 1-naphthyltrimethoxysilane, and 35. methyltrimethoxysilane. A solution of 7g (0.262 mol) and 5-methoxycarbonylnorbornane-2 (or 3) -yltrimethoxysilane 50.3 g (0.175 mol) in toluene 252.2 g was added dropwise at a reaction temperature of 10 to 20 ° C. . After completion of the dropwise addition, after aging for 2 hours at the same temperature, it was confirmed by GC analysis of the reaction solution that all the raw materials were gone. Next, liquid separation was performed after standing, and an oil layer was recovered. Subsequently, it was washed with a 5% aqueous sodium hydrogen carbonate solution, further washed with water, and finally a toluene oil layer was recovered. The solvent was removed from the obtained oil layer with an evaporator, and 1-naphthylsilsesquioxane, methylsilsesquioxane, 5-methoxycarbonylnorbornane-2 (or 3) -ylsilsesquioxane as a white powder 152.4g of coalescence was obtained. As a result of GPC analysis, Mw was 900 and dispersity (Mw / Mn: polystyrene conversion) was 1.1. The spectrum data of the obtained siloxane polymer B are shown below.
Infrared absorption spectrum (IR) data: 3057, 1589 cm ⁻¹ (naphthalene), 1703 to 1726 cm ⁻¹ (—CO—), 991-1115 cm ⁻¹ (Si—O) (Shimadzu IR Prestige-21).
Nuclear magnetic resonance spectrum (NMR) data: 0.070-0.332 ppm (b), 1.042-1.431 ppm (b), 2.12-22.501 (b), 3.370-3.643 ( b), 7.062-8.281 ppm (b) ( ¹ H-NMR solvent: CDCl ₃ , 400 MHz NMR measuring instrument manufactured by JEOL Ltd.).

[Preparation of resist underlayer film forming composition]
50 parts by mass of siloxane polymer A, 50 parts by mass of siloxane polymer B, 0.3 parts by mass of hexadecyltrimethylammonium acetate, 0.75 parts by mass of malonic acid, and PGMEA / EL = 6: 4 as a solvent The siloxane polymer A and the siloxane polymer B were added so as to adjust the solid content concentration to 2.5% by mass.

  The Si concentration in the solid content of the resist underlayer film forming composition of this example was 27.3 mass% (calculated from the blending). This value can be regarded as equivalent to the Si concentration in the resist underlayer film to be formed. The resist underlayer film formed using this resist underlayer film forming composition has a refractive index (n value) at 193 nm of 1.55, an extinction coefficient (k value) of 0.15, and a refractive index (n value) at 248 nm. Was 1.66 and the extinction coefficient (k value) was 0.034.

[Pattern formation]
Bottom layer A was used as the organic bottom layer. Except that the thickness of the resist underlayer film was 50 nm, the same process as in Example 1 was performed to form a pattern. Pattern formation using the resist A was taken as Example 2-1, pattern formation using the resist B was taken as Example 2-2, and pattern formation using the resist C was taken as Example 2-3. The resist film thicknesses and the L / S pattern dimensions of Examples 2-1 to 2-3 are the same as those of Examples 1-1 to 1-3.

<Example 3>
[Siloxane Polymer A]
In this example, the same siloxane polymer as in Example 1 was used.

[Siloxane polymer B]
In this example, the same siloxane polymer as in Example 1 was used.

[Preparation of resist underlayer film forming composition]
100 parts by mass of siloxane polymer A, 100 parts by mass of siloxane polymer B, 3 parts by mass of an acid generator represented by the following formula (26), 3 parts by mass of hexadecyltrimethylammonium acetate and 7.5 parts by mass of malonic acid Partly mixed, and PGMEA / EL = 6: 4 as a solvent was added so as to adjust the solid content concentration of the siloxane polymer A and the siloxane polymer B to 2.5% by mass.

  The Si concentration in the solid content in the resist underlayer film forming composition of this example was 30.0% by mass (calculated from the blending). This value can be regarded as equivalent to the Si concentration in the resist underlayer film to be formed. The resist underlayer film formed using this resist underlayer film forming composition has a refractive index (n value) at 193 nm of 1.50, an extinction coefficient (k value) of 0.15, and a refractive index (n value) at 248 nm. Was 1.66 and the extinction coefficient (k value) was 0.034.

[Pattern formation]
The bottom layer A was used as the organic bottom layer. Except that the thickness of the resist underlayer film was 50 nm, the same process as in Example 1 was performed to form a pattern. Pattern formation using the resist A was taken as Example 3-1, pattern formation using the resist B was taken as Example 3-2, and pattern formation using the resist C was taken as Example 3-3. The resist film thicknesses and the L / S pattern dimensions in Examples 3-1 to 3-3 are the same as those in Examples 1-1 to 1-3.

<Comparative Example 1>
A composition for forming a resist underlayer film was prepared in the same manner as in Example 1 except that only the siloxane polymer A represented by the above formula (14) was used without using the siloxane polymer B. The Si concentration in the solid content of the resist underlayer film composition of this comparative example was 35% by mass (calculated from the formulation). This value can be regarded as equivalent to the Si concentration in the resist underlayer film to be formed. The resist underlayer film formed using this resist underlayer film forming composition has a refractive index (n value) at 193 nm of 1.72 and an extinction coefficient (k value) of 0.332 and a refractive index at 248 nm (n Value) was 1.56, and the extinction coefficient (k value) was 0.0008. Further, the bottom layer A was used as the organic bottom layer, and the pattern was formed in the same manner as in Example 1. Pattern formation using the resist A was set as Comparative Example 1-1, pattern formation using the resist B was set as Comparative Example 1-2, and pattern formation using the resist C was set as Comparative Example 1-3. The resist film thicknesses and the L / S pattern dimensions of Comparative Examples 1-1 to 1-3 are the same as those of Examples 1-1 to 1-3.

<Pattern evaluation>
The shape of the pattern formed in the example and the comparative example was evaluated. The evaluation was performed by magnifying and observing the pattern state using an SEM (scanning electron microscope). As a result, in all of the comparative examples, the resist pattern was shaped like a skirt, but in the examples, any resist pattern was a rectangular pattern having high perpendicularity to the surface of the resist underlayer film. There was no solitary or undercut shape. From the above, it was confirmed in this example that good matching characteristics between the resist underlayer film and the resist film can be obtained regardless of the resist composition.

<Etching evaluation>
For Example 1-4 using the resist C for the bottom layer B, etching evaluation was also performed after the formation of the L / S pattern. The etching apparatus used was Telius (manufactured by Tokyo Electron). The etching conditions are shown in Table 1.

First, the resist underlayer film was etched using the patterned resist C as a mask, and then the bottom layer B was etched using the resist C and the resist underlayer film as a mask. Subsequently, at this time, the resist C remaining as a mask was also removed. Subsequently, the substrate (SiO ₂ ) was etched using the resist underlayer film and the bottom layer B as a mask, and the resist underlayer film remaining as a mask was also removed at the same time. Through the above steps, a substrate having the L / S pattern transferred thereon was obtained. At this time, the change width from the L / S pattern dimension (90 nm) of the resist layer in the L / S pattern dimension transferred to the substrate was 1.7 nm or less. Finally, the remaining bottom layer B was removed with an O ₂ / N ₂ ashing gas having a mixing ratio of 80/20.

  The comparative example is not evaluated here because it is clear that the formed pattern has a trailing shape and accurate pattern transfer cannot be performed.

  By forming the resist underlayer film according to the present invention, it was possible to obtain a rectangular resist pattern instead of a skirt shape, and the resist pattern dimensions could be transferred to the lower layer sequentially and accurately in each etching step. . That is, it was possible to obtain a substrate formed with more accurate pattern dimensions.

It is a figure for demonstrating pattern formation using the composition for resist lower layer film formation which concerns on this invention.

Explanation of symbols

20 Substrate 22 Resist underlayer film 24 Resist film 26 Organic bottom layer

Claims (13)

A resist underlayer film forming composition comprising a siloxane polymer component having a repeating unit represented by the following general formulas (1) and (2).

[In the formulas (1) and (2), Ph represents a phenyl group. Ar represents a naphthyl group, an anthracene group, or a phenanthrene group. R ₁ and R ₂ each independently represent a hydrogen atom or a monovalent organic group. Moreover, several R < ₁ > and R < ₂ > may differ. a and b are 0, 1, or 2, respectively. ] The composition for forming a resist underlayer film according to claim 1, wherein the siloxane polymer component further has a repeating unit represented by the following general formula (3).

[In formula (3), Me represents a methyl group. R ₃ is independently a hydrogen atom, an alkyl group, a hydroxyl group, a crosslinkable monovalent organic group, or a hydroxyl group, a polyether group, a carbonyl group, an ester group, a lactone group, an amide group, an ether group, and It represents a monovalent organic group having at least one functional group selected from the group consisting of nitrile groups. Or it may be different plurality of R ₃ to each other. c is 0, 1, or 2. ] The composition for forming a resist underlayer film according to claim 1 or 2, wherein the siloxane polymer component further has a repeating unit represented by the following general formula (4).

[In Formula (4), R ₃ is independently a hydrogen atom, an alkyl group, a hydroxyl group, a monovalent organic group capable of crosslinking, or a hydroxyl group, a polyether group, a carbonyl group, an ester group, a lactone group, A monovalent organic group having at least one functional group selected from the group consisting of an amide group, an ether group, and a nitrile group. Or it may be different plurality of R ₃ to each other. d is 0, 1, or 2. ] The composition for forming a resist underlayer film according to any one of claims 1 to 3, wherein the siloxane polymer component further has a repeating unit represented by the following general formula (5).

[In the formula (5), R ₃ is independently a hydrogen atom, an alkyl group, a hydroxyl group, a monovalent organic group capable of crosslinking, or a hydroxyl group, a polyether group, a carbonyl group, an ester group, a lactone group, A monovalent organic group having at least one functional group selected from the group consisting of an amide group, an ether group, and a nitrile group. R represents a monovalent organic group having at least one functional group selected from an ester group and a polyether group. Or it may be different plurality of R ₃ to each other. e is 0, 1 or 2; ]   The siloxane polymer component contains a siloxane polymer A having a repeating unit represented by the general formula (1) and a siloxane polymer B having a repeating unit represented by the general formula (2). The composition for forming a resist underlayer film according to any one of claims 1 to 4.   6. The resist underlayer film forming composition according to claim 5, wherein the siloxane polymer B further has a repeating unit represented by the general formula (3).   The composition for forming a resist underlayer film according to claim 5 or 6, wherein the siloxane polymer A further has a repeating unit represented by the general formula (3).   The composition for forming a resist underlayer film according to any one of claims 5 to 7, wherein the siloxane polymer A further has a repeating unit represented by the general formula (4).   The composition for forming a resist underlayer film according to any one of claims 5 to 8, wherein the siloxane polymer A further has a repeating unit represented by the general formula (5).   10. The composition for forming a resist underlayer film according to claim 5, wherein the content of the siloxane polymer B is 10 parts by mass to 1,000 parts by mass with respect to 100 parts by mass of the siloxane polymer A. .   The composition for forming a resist underlayer film according to any one of claims 5 to 10, wherein the siloxane polymer A has a mass average molecular weight of 500 to 400,000.   The composition for forming a resist underlayer film according to any one of claims 5 to 11, wherein the siloxane polymer B has a mass average molecular weight of 300 to 8,000.   A resist underlayer film formed by applying the composition for forming a resist underlayer film according to claim 1 and baking at a predetermined temperature.

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