JP5644339B2 - Resist underlayer film forming composition, resist underlayer film and pattern forming method - Google Patents

Description

  The present invention relates to a resist underlayer film forming composition, a resist underlayer film, and a pattern forming method.

  Along with miniaturization of semiconductor devices and the like, a required characteristic level such as pattern formability is increasing with respect to a resist material used as a mask in pattern formation on a substrate. In addition, the film thickness of the resist film itself tends to be thinned to less than 100 nm in order to improve the pattern formability and the like. However, since a resist film having a thickness of less than 100 nm is difficult to process sufficiently by etching, a method using a multilayer resist film has recently attracted attention as a solution, and adaptation by device manufacturers has become active. (See JP 2001-284209 A).

  As a general method using this multilayer resist film, the following method is adopted. First, a resist underlayer film having an etching selection ratio different from that of the surface resist film is interposed between the resist film and the substrate to be processed to form a resist pattern on the surface resist film. Thereafter, the pattern is transferred to the resist underlayer film by dry etching using the obtained resist pattern as a mask. Subsequently, using the obtained resist underlayer film pattern as a mask, the pattern is transferred to the substrate to be processed by dry etching. Further, a three-layer resist method in which another film is interposed between the resist underlayer film and the substrate to be processed is also employed.

  In such a multilayer resist method, in order to finally form a precise pattern on the substrate to be processed, it is necessary to use materials having a high etching selectivity between the surface resist film and the substrate and the resist underlayer film. That is, the resist underlayer film is easy to be etched when the resist underlayer film is processed using the resist film as a mask, and is difficult to be etched when the substrate is processed using the resist underlayer film as a mask. An excellent balance is required.

  Further, when the pattern becomes finer, the contact area between the patterned resist film and the resist underlayer film decreases. At this time, if the adhesiveness between the two is low, the resist film is likely to be peeled off from the resist underlayer film due to stress during development and rinsing in the formed resist pattern. As a result, the pattern is transferred to the substrate to be processed. May not be done sufficiently. On the other hand, with the progress of multilayer wiring, a series of process temperatures are also set to the upper limit of heat curing (baking) treatment at 220 to 250 ° C., and each film including the resist underlayer film is sufficiently cured by heating, It has also become difficult to ensure adhesion, etching resistance, and etching selectivity.

  Furthermore, in order to further improve the pattern formability, it is necessary to reduce the thickness of the resist underlayer film as well as the thickness of the surface resist film. However, the resist underlayer film also functions as an antireflection film in the patterning of the resist film, and there is an inconvenience that reducing the film thickness leads to a decrease in the antireflection function. In addition, various curable compositions including a composition for forming a resist underlayer film are also required to have excellent storage stability.

  Under such circumstances, various proposals for a composition for forming a resist underlayer film have been made in order to improve pattern formability and the like (see JP 2010-85912 A and JP 2008-39811 A). Resist underlayer capable of exhibiting excellent pattern formability by providing high adhesion to the resist film, excellent etching selectivity with respect to the resist film and the substrate, low reflectivity, etc. Development of a film-forming composition has not yet been achieved.

JP 2001-284209 A JP 2010-85912 A JP 2008-39811 A

  The present invention has been made based on the above circumstances, and has excellent storage stability, and a cured film as a resist underlayer film has high adhesion to a resist film, and excellent resistance to a resist film and a substrate to be processed. It aims at providing the composition for resist underlayer film formation which can exhibit the outstanding pattern formation property by providing an etching selectivity and low reflectivity. Another object of the present invention is to provide a resist underlayer film having such characteristics and a pattern forming method excellent in pattern formability.

（式（１）中、Ｒ^１は、それぞれ独立して、水素原子、炭素数１〜８のアルキル基又は炭素数１〜８のヒドロキシアルキル基である。Ａ^ｂ−は、ｂ価の有機酸アニオンである。ｂは、１又は２である。） The invention made to solve the above problems is
[A] polysiloxane,
[B] A compound represented by the following formula (1) (hereinafter also referred to as “[B] compound”),
[C] A resist underlayer film forming composition containing an organic acid and [D] an organic solvent.

(In Formula (1), each R ¹ is independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms. A ^b- is a b-valent organic acid. An anion, b is 1 or 2)

  The resist underlayer film forming composition contains a [C] organic acid. For this reason, since [C] organic acid volatilizes by heating, the obtained resist underlayer film can be made into a porous shape. When the resist underlayer film has a porous shape, the resist film laminated on the resist underlayer film surface has improved adhesion with the resist underlayer film due to the anchor effect. Therefore, according to the composition for forming a resist underlayer film, the pattern formability can be improved due to the high adhesion between the resist underlayer film and the resist film. Moreover, [C] organic acid can improve the storage stability of the said resist underlayer film composition.

  In addition, according to the resist underlayer film forming composition, the [B] compound that is an organic acid ammonium salt suitably functions as a curing catalyst for [A] polysiloxane, and thus the resulting resist underlayer film has a porous shape. Despite being, it can exhibit excellent etching resistance during substrate processing. Furthermore, according to the resist underlayer film composition, by providing such a composition, a resist underlayer film having a high etching selectivity and low reflectivity can be obtained, and as a result, the pattern forming property can be improved. .

  [A] The content of the [B] compound with respect to 100 parts by mass of silicon atoms contained in the polysiloxane is preferably 0.01 parts by mass or more and 5 parts by mass or less. According to the resist underlayer film composition, by keeping the content of the [B] compound in the above range, the etching resistance of the obtained resist underlayer film and the adhesion with the resist film are further improved while maintaining the storage stability. Can be increased.

  [A] The content of the [C] organic acid with respect to 100 parts by mass of silicon atoms contained in the polysiloxane is preferably 10 parts by mass or more and 300 parts by mass or less. According to the resist underlayer film composition, by setting the content of [C] organic acid in the above range, the porosity of the obtained resist underlayer film can be adjusted to an appropriate range, and the adhesion to the resist film can be improved. Etching resistance can be achieved at a high level.

（式（２）中、Ｒ^２は、単結合、酸素原子、ｄ価の炭素数１〜６の直鎖状若しくは分岐状の脂肪族飽和炭化水素基、ｄ価の芳香族炭化水素基又はｄ価の複素環式基であり、この芳香族炭化水素基及び複素環式基の水素原子の一部又は全部は置換されていてもよい。複数のＲ^３は、それぞれ独立して、１価の有機基である。複数のＸは、それぞれ独立して、単結合、メチレン基、炭素数２〜５の直鎖状若しくは分岐状のアルキレン基又はフェニレン基であり、このメチレン基、アルキレン基及びフェニレン基の水素原子の一部又は全部が置換されていてもよい。複数のＹは、それぞれ独立して、ハロゲン原子又は−ＯＲ^６である。Ｒ^６は、１価の有機基である。ｃは、０〜２の整数である。ｄは、２又は３である。但し、ｄが３の場合、Ｒ^２が単結合又は酸素原子である場合はない。
式（３）中、Ｒ^４及びＲ^５は、それぞれ独立して、１価の有機基である。） [A] The polysiloxane is derived from at least one compound selected from the group consisting of a tetraalkoxysilane-derived structural unit, a compound represented by the following formula (2), and a compound represented by the following formula (3). It is preferable to have a structural unit.

(In Formula (2), R ² is a single bond, an oxygen atom, a d-valent C 1-6 linear or branched aliphatic saturated hydrocarbon group, a d-valent aromatic hydrocarbon group, or d. the valence of the heterocyclic group, the aromatic hydrocarbon group and partially or. more R ³ which may be substituted in all of the hydrogen atoms of the heterocyclic group are each independently a monovalent A plurality of X's are each independently a single bond, a methylene group, a linear or branched alkylene group having 2 to 5 carbon atoms or a phenylene group, and the methylene group, alkylene group and phenylene group A part or all of the hydrogen atoms in the group may be substituted, and each of the plurality of Y is independently a halogen atom or —OR ^6. R ⁶ is a monovalent organic group, c is , the .d an integer of 0 to 2, is 2 or 3. However, if d is 3, R But not if it is a single bond or an oxygen atom.
In formula (3), R ⁴ and R ⁵ are each independently a monovalent organic group. )

  [A] When the polysiloxane has the above structural unit, the storage stability is further increased, and the silicon content can be increased. As a result, the adhesion to the resist film and the etching selectivity can be further improved. it can.

  Since the resist underlayer film of the present invention is formed using the above resist underlayer film forming composition, it has high adhesion to the resist film, excellent etching selectivity with respect to the resist film and the substrate to be processed, and low reflection. It has sex.

The BET specific surface area of the resist underlayer film is preferably 10 m ² / g or more and 150 m ² / g or less. Since the resist underlayer film has a specific surface area in such a range, the adhesion with the resist film and the etching resistance can be achieved at a high level.

The pattern forming method of the present invention comprises:
(1) applying the resist underlayer film forming composition on a substrate to be processed to form a resist underlayer film;
(2) applying a resist composition on the resist underlayer film to form a resist film;
(3) exposing the resist film by selectively irradiating the resist film with radiation through a photomask;
(4) developing the exposed resist film to form a resist pattern;
And (5) forming a pattern by dry etching the resist underlayer film and the substrate to be processed using the resist pattern as a mask.

  Since the pattern formation method uses the composition for forming a resist underlayer film that is excellent in adhesion to the resist film and etching selectivity as described above, a fine pattern can be efficiently formed. In addition, due to the adhesion utilizing the excellent anchor effect of the resist underlayer film of the present invention, even a pattern formed by a pattern formation method other than photolithography, for example, a pattern formed by an imprint method, adheres well, and a fine pattern is formed. Can be given.

  As described above, according to the resist underlayer film composition of the present invention, the storage stability is excellent, and the cured film as the resist underlayer film has high adhesion to the resist film, and excellent resistance to the resist film and the substrate to be processed. By providing the etching selectivity and low reflectivity, excellent pattern forming properties can be exhibited.

  Hereinafter, embodiments of the resist underlayer film forming composition, resist underlayer film, and pattern forming method of the present invention will be described in this order.

<Composition for forming resist underlayer film>
The composition for forming a resist underlayer film of the present invention contains [A] polysiloxane, [B] compound, [C] organic acid and [D] organic solvent, and may further contain other optional components.

<[A] polysiloxane>
[A] The polysiloxane is not particularly limited as long as it is a polymer of a compound having a siloxane bond. This [A] polysiloxane is cured by heating using a [B] compound or [C] organic acid as a catalyst.

  [A] The polysiloxane can be usually obtained by hydrolytic condensation of a hydrolyzable silane compound in the presence of a catalyst. Preferred examples of the hydrolyzable silane compound include tetraalkoxysilane, a compound represented by the above formula (2), and a compound represented by the above formula (3).

<Tetraalkoxysilane>
Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetra-iso-propoxysilane. Among these, tetramethoxysilane and tetraethoxysilane are preferable.

<Compound represented by the above formula (2)>
In the compound represented by the above formula (2), examples of the d-valent linear or branched aliphatic hydrocarbon group represented by R ² represented by R ² include methane, ethane, and propane. And a group having a structure in which one or two hydrogens are removed from a linear aliphatic hydrocarbon such as 2-ethylpropane or branched aliphatic hydrocarbons such as 2-ethylpropane and 2-ethylbutane.

Examples of the d-valent aromatic hydrocarbon group represented by R ² include divalent aromatic groups such as a phenylene group, a biphenylene group, a terphenylene group, a benzylene group, a phenyleneethylene group, a phenylenecyclohexylene group, and a naphthylene group. Examples thereof include a hydrocarbon group, and a trivalent aromatic hydrocarbon group such as a benzenetriyl group, a biphenyltriyl group, a terphenyltriyl group, and a toluenetoyl group.

Examples of the d-valent heterocyclic group represented by R ² include divalent heterocyclic groups such as pyridylene group and furylene group, pyridine triyl group, tetrahydrofuran triyl group, tetrahydropyrantriyl group, tetrahydro And trivalent heterocyclic groups such as a thiofurantriyl group and a tetrahydrothiopyrantriyl group.

Examples of the monovalent organic group represented by R ³ include a monovalent chain hydrocarbon group having 1 to 30 carbon atoms, a monovalent aliphatic cyclic hydrocarbon group having 3 to 30 carbon atoms, and 6 to 6 carbon atoms. 30 monovalent aromatic hydrocarbon groups, etc., and some or all of the hydrogen atoms of these groups were substituted with substituents such as epoxy groups, ester groups, alkoxy groups, hydroxy groups, etc. The group can be mentioned.

  Examples of the monovalent chain hydrocarbon group having 1 to 30 carbon atoms include alkyl groups having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group, carbons such as an ethenyl group, a propenyl group, and a butenyl group. C1-C30 alkynyl groups, such as a C1-C30 alkenyl group, an ethynyl group, a propynyl group, a butynyl group, etc. can be mentioned.

  Examples of the monovalent aliphatic cyclic hydrocarbon group having 1 to 30 carbon atoms include monocyclic saturated hydrocarbon groups such as cyclobutyl group and cyclohexyl group, polycyclic unsaturated hydrocarbon groups such as cyclobutenyl group and cyclohexenyl group, Examples thereof include polycyclic saturated hydrocarbon groups such as a bicyclo [2.2.1] heptanyl group, polycyclic unsaturated hydrocarbon groups such as a bicyclo [2.2.1] heptenyl group, and the like.

  Examples of the monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms include a phenyl group, a biphenyl group, a terphenyl group, a benzyl group, and a naphthyl group.

  A plurality of X's are each independently a single bond, a methylene group, a linear or branched alkylene group having 2 to 5 carbon atoms or a phenylene group, and the hydrogen atoms of the methylene group, alkylene group and phenylene group Some or all of them may be substituted. Examples of the linear or branched alkylene group having 2 to 5 carbon atoms include an ethylene group, a propylene group, and a butylene group.

Y is a halogen atom or —OR ⁶ (where R ⁶ is a monovalent organic group), and examples of the halogen atom include a chlorine atom and a bromine atom. Examples of the monovalent organic group for R ⁶ include those exemplified for R ³ .

In the above formula (2), d is 2, R ² is a single bond, a divalent linear or branched aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, or a divalent aromatic hydrocarbon. What is group is preferable.

In the above formula (2), specific examples of the compound when R ² is a single bond include hexamethoxydisilane, hexaethoxydisilane, hexaphenoxydisilane, 1,1,1,2,2-pentamethoxy-2- Methyldisilane, 1,1,1,2,2-pentaethoxy-2-methyldisilane, 1,1,1,2,2-pentaphenoxy-2-methyldisilane, 1,1,1,2,2-penta Methoxy-2-ethyldisilane, 1,1,1,2,2-pentaethoxy-2-ethyldisilane, 1,1,1,2,2-pentaphenoxy-2-ethyldisilane, 1,1,1,2 , 2-pentamethoxy-2-phenyldisilane, 1,1,1,2,2-pentaethoxy-2-phenyldisilane, 1,1,1,2,2-pentaphenoxy-2-phenyldisilane, 1,1 , 2,2-Tetramethoxy-1,2-dimethyldisilane, 1,1,2,2-tetraethoxy-1,2-dimethyldisilane, 1,1,2,2-tetraphenoxy-1,2-dimethyldisilane 1,1,2,2-tetramethoxy-1,2-diethyldisilane, 1,1,2,2-tetraethoxy-1,2-diethyldisilane, 1,1,2,2-tetraphenoxy-1, 2-diethyldisilane, 1,1,2,2-tetramethoxy-1,2-diphenyldisilane, 1,1,2,2-tetraethoxy-1,2-diphenyldisilane, 1,1,2,2-tetra Phenoxy-1,2-diphenyldisilane, 1,1,2-trimethoxy-1,2,2-trimethyldisilane, 1,1,2-triethoxy-1,2,2-trimethyldisilane, 1,1,2-tripheno Si-1,2,2-trimethyldisilane, 1,1,2-trimethoxy-1,2,2-triethyldisilane, 1,1,2-triethoxy-1,2,2-triethyldisilane, 1,1,2 -Triphenoxy-1,2,2-triethyldisilane, 1,1,2-trimethoxy-1,2,2-triphenyldisilane, 1,1,2-triethoxy-1,2,2-triphenyldisilane, , 1,2-Triphenoxy-1,2,2-triphenyldisilane, 1,2-dimethoxy-1,1,2,2-tetramethyldisilane, 1,2-diethoxy-1,1,2,2- Tetramethyldisilane, 1,2-diphenoxy-1,1,2,2-tetramethyldisilane, 1,2-dimethoxy-1,1,2,2-tetraethyldisilane, 1,2-diethoxy-1,1,2 , 2- Traethyldisilane, 1,2-diphenoxy-1,1,2,2-tetraethyldisilane, 1,2-dimethoxy-1,1,2,2-tetraphenyldisilane, 1,2-diethoxy-1,1,2 , 2-tetraphenyldisilane, 1,2-diphenoxy-1,1,2,2-tetraphenyldisilane, and the like.

  Among these, hexamethoxydisilane, hexaethoxydisilane, 1,1,2,2-tetramethoxy-1,2-dimethyldisilane, 1,1,2,2-tetraethoxy-1,2-dimethyldisilane, 1, 1,2,2-tetramethoxy-1,2-diphenyldisilane, 1,2-dimethoxy-1,1,2,2-tetramethyldisilane, 1,2-diethoxy-1,1,2,2-tetramethyl Disilane, 1,2-dimethoxy-1,1,2,2-tetraphenyldisilane, and 1,2-diethoxy-1,1,2,2-tetraphenyldisilane are preferred.

In the above formula (2), as a specific example of a compound in the case where R ² is a divalent linear or branched aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, bis (trimethoxysilyl) ) Methane, bis (triethoxysilyl) methane, bis (tri-n-propoxysilyl) methane, bis (tri-iso-propoxysilyl) methane, bis (tri-n-butoxysilyl) methane, bis (tri-sec-) Butoxysilyl) methane, bis (tri-tert-butoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1,2-bis (tri-n- Propoxysilyl) ethane, 1,2-bis (tri-iso-propoxysilyl) ethane, 1,2-bis (tri-n-butoxysilyl) ethane, 1,2-bis (to Li-sec-butoxysilyl) ethane, 1,2-bis (tri-tert-butoxysilyl) ethane, 1- (dimethoxymethylsilyl) -1- (trimethoxysilyl) methane, 1- (diethoxymethylsilyl)- 1- (triethoxysilyl) methane, 1- (di-n-propoxymethylsilyl) -1- (tri-n-propoxysilyl) methane, 1- (di-iso-propoxymethylsilyl) -1- (tri- iso-propoxysilyl) methane, 1- (di-n-butoxymethylsilyl) -1- (tri-n-butoxysilyl) methane, 1- (di-sec-butoxymethylsilyl) -1- (tri-sec- Butoxysilyl) methane, 1- (di-tert-butoxymethylsilyl) -1- (tri-tert-butoxysilyl) methane, 1- (dimethoxymethyl) Rusilyl) -2- (trimethoxysilyl) ethane, 1- (diethoxymethylsilyl) -2- (triethoxysilyl) ethane, 1- (di-n-propoxymethylsilyl) -2- (tri-n-propoxy) Silyl) ethane, 1- (di-iso-propoxymethylsilyl) -2- (tri-iso-propoxysilyl) ethane, 1- (di-n-butoxymethylsilyl) -2- (tri-n-butoxysilyl) Ethane, 1- (di-sec-butoxymethylsilyl) -2- (tri-sec-butoxysilyl) ethane, 1- (di-tert-butoxymethylsilyl) -2- (tri-tert-butoxysilyl) ethane;
Bis (dimethoxymethylsilyl) methane, bis (diethoxymethylsilyl) methane, bis (di-n-propoxymethylsilyl) methane, bis (di-iso-propoxymethylsilyl) methane, bis (di-n-butoxymethylsilyl) ) Methane, bis (di-sec-butoxymethylsilyl) methane, bis (di-tert-butoxymethylsilyl) methane, 1,2-bis (dimethoxymethylsilyl) ethane, 1,2-bis (diethoxymethylsilyl) Ethane, 1,2-bis (di-n-propoxymethylsilyl) ethane, 1,2-bis (di-iso-propoxymethylsilyl) ethane, 1,2-bis (di-n-butoxymethylsilyl) ethane, 1,2-bis (di-sec-butoxymethylsilyl) ethane, 1,2-bis (di-tert-butoxymethyl) ) Ethane and the like.

  Among these, bis (trimethoxysilyl) methane, bis (triethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1- (dimethoxymethylsilyl) ) -1- (trimethoxysilyl) methane, 1- (diethoxymethylsilyl) -1- (triethoxysilyl) methane, 1- (dimethoxymethylsilyl) -2- (trimethoxysilyl) ethane, 1- (di Ethoxymethylsilyl) -2- (triethoxysilyl) ethane, bis (dimethoxymethylsilyl) methane, bis (diethoxymethylsilyl) methane, 1,2-bis (dimethoxymethylsilyl) ethane, 1,2-bis (di Ethoxymethylsilyl) ethane is preferred.

In the above formula (2), as R ² is a divalent aromatic hydrocarbon group, 1,2-bis (trimethoxysilyl) benzene, 1,2-bis (triethoxysilyl) benzene, 1,2-bis (tri-n-propoxysilyl) benzene, 1,2-bis (tri-iso-propoxysilyl) benzene, 1,2-bis (tri-n-butoxysilyl) benzene, 1,2-bis (Tri-sec-butoxysilyl) benzene, 1,2-bis (tri-tert-butoxysilyl) benzene, 1,3-bis (trimethoxysilyl) benzene, 1,3-bis (triethoxysilyl) benzene, 1 , 3-bis (tri-n-propoxysilyl) benzene, 1,3-bis (tri-iso-propoxysilyl) benzene, 1,3-bis (tri-n-butoxysilyl) ) Benzene, 1,3-bis (tri-sec-butoxysilyl) benzene, 1,3-bis (tri-tert-butoxysilyl) benzene, 1,4-bis (trimethoxysilyl) benzene, 1,4-bis (Triethoxysilyl) benzene, 1,4-bis (tri-n-propoxysilyl) benzene, 1,4-bis (tri-iso-propoxysilyl) benzene, 1,4-bis (tri-n-butoxysilyl) Examples thereof include benzene, 1,4-bis (tri-sec-butoxysilyl) benzene, 1,4-bis (tri-tert-butoxysilyl) benzene and the like.

  Among these, 1,2-bis (trimethoxysilyl) benzene, 1,2-bis (triethoxysilyl) benzene, 1,3-bis (trimethoxysilyl) benzene, 1,3-bis (triethoxysilyl) Benzene, 1,4-bis (trimethoxysilyl) benzene, and 1,4-bis (triethoxysilyl) benzene are preferred.

<Compound represented by the above formula (3)>
In the compound represented by the above formula (3), R ⁴ is a monovalent organic group. Examples of the organic group include those exemplified for R ³ above, but a monovalent hydrocarbon group having an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aromatic ring. And a group in which some or all of these hydrogen atoms may be substituted and may have an oxygen atom, -CO- or -COO- between these carbon-carbon bonds is preferred. .

  Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Examples of the cycloalkyl group having 3 to 20 carbon atoms include a cyclohexyl group, a cyclohexenyl group, and a bicyclo [2.2.1] heptanyl group. Examples of the monovalent hydrocarbon group having an aromatic ring include a phenyl group, a biphenyl group, and a benzyl group.

And a monovalent hydrocarbon group having an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms or an aromatic ring, which is a preferred group as the organic group for R ⁴ , and these hydrogen atoms Examples of the group in which a part or all of them are substituted and the group which may have an oxygen atom, -CO- or -COO- between these carbon-carbon bonds include an epoxy group, an ester group, and an alkoxy group , Groups containing a hydroxy group, a group having a silicon-silicon bond, and the like. Specific examples of these groups include groups represented by the following formulas. In the following formula, (Si) represents a bonding site with Si.

In the above formula (3), R ⁵ is a monovalent organic group. The plurality of R ⁵ may be the same or different. Examples of the monovalent organic group represented by R ⁵ include those exemplified above for R ^{3 and the} like.

  Specific examples of the compound represented by the above formula (3) include 3- (trimethoxysilyl) propyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, N-3- (methacryloxy-2-hydroxypropyl) -3. -Aminopropyltriethoxysilane, 2- (trimethoxysilyl) ethyl methacrylate, 2- (triethoxysilyl) ethyl methacrylate, trimethoxysilylmethyl methacrylate, methacryloxypropyltris (methoxyethoxy) silane, triethoxysilylmethyl methacrylate, 3 -[Tris (trimethylsiloxy) silyl] propyl methacrylate, 3- [Tris (dimethylvinylsiloxy)] propyl methacrylate, 3- (trimethoxysilyl) propyl acrylate, 3- (triethoxysilane) ) Propyl acrylate,

2-cyanoethyltrimethoxysilane, 2-cyanoethyltriethoxysilane, 2-cyanoethyltri-n-propoxysilane, 2-cyanoethyltri-iso-propoxysilane,
Trimethoxysilane, triethoxysilane, tri-n-propoxysilane, tri-iso-propoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltri-iso-propoxysilane, ethyltrimethoxysilane , Ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltri-iso-propoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-propoxysilane, vinyltri-iso-propoxysilane, n-propyltrimethoxysilane N-propyltriethoxysilane, n-propyltri-n-propoxysilane, n-propyltri-iso-propoxysilane, i-propyltrimethoxysilane, i-propylto Ethoxysilane, i-propyltri-n-propoxysilane, i-propyltri-iso-propoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-butyltri-n-propoxysilane, n-butyltri- iso-propoxysilane, sec-butyltrimethoxysilane, sec-butyl-i-triethoxysilane, sec-butyl-tri-n-propoxysilane, sec-butyl-tri-iso-propoxysilane, t-butyltrimethoxysilane , T-butyltriethoxysilane, t-butyltri-n-propoxysilane, t-butyltri-iso-propoxysilane, cyclopropyltrimethoxysilane, cyclopropyltriethoxysilane, cyclopropyl-tri-n-propoxysilane, cyclo Propyl-tri-iso-propoxysilane, cyclobutyltrimethoxysilane, cyclobutyltriethoxysilane, cyclobutyl-tri-n-propoxysilane, cyclobutyl-tri-iso-propoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclopentyl -Tri-n-propoxysilane, cyclopentyl-tri-iso-propoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexyl-tri-n-propoxysilane, cyclohexyl-tri-iso-propoxysilane, cyclohexenyltrimethoxysilane Cyclohexenyltriethoxysilane, cyclohexenyl-tri-n-propoxysilane, cyclohexenyl-tri-iso-pro Poxysilane, Cyclohexenylethyltrimethoxysilane, Cyclohexenylethyltriethoxysilane, Cyclohexenylethyl-tri-n-propoxysilane, Cyclohexenylethyltri-iso-propoxysilane, Cyclooctenyltrimethoxysilane, Cyclooctenyltriethoxysilane , Cyclooctanyl-tri-n-propoxysilane, cyclooctanyl-tri-iso-propoxysilane, cyclopentadienylpropyltrimethoxysilane, cyclopentadienylpropyltriethoxysilane, cyclopentadienylpropyl-tri-n -Propoxysilane, cyclopentadienylpropyl-tri-iso-propoxysilane, bicycloheptenyltrimethoxysilane, bicycloheptenyltriethoxysilane, Chloheptenyl-tri-n-propoxysilane, bicycloheptenyl-tri-iso-propoxysilane, bicycloheptyltrimethoxysilane, bicycloheptyltriethoxysilane, bicycloheptyl-tri-n-propoxysilane, bicycloheptyl-tri-iso-propoxy Examples include silane, adamantyltrimethoxysilane, adamantyltriethoxysilane, adamantyl-tri-n-propoxysilane, adamantyl-tri-iso-propoxysilane, and the like.

  Moreover, as a light absorptive monomer which is a compound represented by the formula (3), phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-iso-propoxysilane, benzyltrimethoxysilane , Benzyltriethoxysilane, benzyltri-n-propoxysilane, benzyltri-iso-propoxysilane, tolyltrimethoxysilane, tolyltriethoxysilane, tolyltri-n-propoxysilane, tolyltri-iso-propoxysilane, phenethyltrimethoxysilane, phenethyl Triethoxysilane, phenethyltri-n-propoxysilane, phenethyltri-iso-propoxysilane, naphthyltrimethoxysilane, naphthyltriethoxysilane, naphthyltri-n- Ropokishishiran, can be mentioned Nafuchirutori -iso- propoxy silane.

Among these, 2-cyanoethyltrimethoxysilane, 3- (trimethoxysilyl) propyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, trimethoxysilylmethyl methacrylate, 2- (trimethoxysilyl) ethyl methacrylate, 2- ( Triethoxysilyl) ethyl methacrylate methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, iso-propyltrimethoxysilane, iso-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, iso-butyltrimethoxysilane Lan, iso-butyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexenyltrimethoxysilane, cyclohexenyltriethoxysilane Phenyltrimethoxysilane, phenyltriethoxysilane, benzyltrimethoxysilane, benzyltriethoxysilane, phenethyltrimethoxysilane, and phenethyltriethoxysilane are preferable.

  In addition, as this [A] polysiloxane, at least 1 sort (s) chosen from the group which consists of the structural unit derived from tetraalkoxysilane, the compound represented by the said Formula (2), and the compound represented by the said Formula (3). It is preferable to have a structural unit derived from this compound. [A] When the polysiloxane has the above structural unit, the storage stability is further increased, and the silicon content can be increased. As a result, the adhesion to the resist film and the etching selectivity can be further improved. it can.

  Moreover, the usage ratio of the tetraalkoxysilane, the compound represented by the above formula (2) and the compound represented by the above formula (3) is the total number of moles of tetraalkoxysilane (I), and the above formula (2). When the total number of moles of the compound represented by formula (3) and the compound represented by formula (3) is (II), the ratio (I / II) is 1 or more, preferably 2 or more, more preferably 3 or more. And it is preferably 20 or less. When this ratio I / II is less than 1, the dry processing speed as the resist underlayer film material is faster than the base, and it may be difficult to maintain sufficient processing mask resistance. On the contrary, if the ratio I / II exceeds 20, the residual amount of reactive active groups in the resist underlayer film may increase and storage stability may decrease.

  The polysiloxane used in the present invention includes other hydrolyzable silanes in addition to the silane compounds (tetraalkoxysilane, the compound represented by the above formula (2) and the compound represented by the above formula (3)). You may use a compound together. In addition, as a range which does not impair the effect of this invention, the mass of the structural unit derived from another hydrolyzable silane compound is 30 mass with respect to 100 mass of structural units derived from the said silane compound in [A] polysiloxane. It is preferable not to exceed the part.

  [A] The weight average molecular weight of the polysiloxane is preferably 20,000 or less, more preferably 500 or more and 10,000 or less, and particularly preferably 800 or more and 6,000 or less. [A] By making the weight average molecular weight of polysiloxane into the said range, the applicability | paintability of a composition and the intensity | strength and workability of the resist underlayer film obtained can be made compatible on a high level. Here, the weight average molecular weight means a weight average molecular weight in terms of polystyrene using GPC (gel permeation chromatography) using tetrahydrofuran as a mobile phase.

<[A] Production method of polysiloxane>
[A] Polysiloxane is prepared by, for example, using the hydrolyzable silane compound as a starting material, dissolving the starting material in an organic solvent, and adding water intermittently or continuously to the solution to perform a hydrolytic condensation reaction. Can be manufactured. At this time, a catalyst may be used. This catalyst may be dissolved or dispersed in advance in an organic solvent, or may be dissolved or dispersed in water to be added. Moreover, as temperature for performing a hydrolysis-condensation reaction, it is 0 to 100 degreeC normally.

  In addition, when [A] polysiloxane is manufactured using a plurality of types of hydrolyzable silane compounds, a mixture of all of the plurality of types of hydrolyzable silane compounds may be subjected to a hydrolytic condensation reaction at a time, or each compound The hydrolytic condensation reaction may be carried out using the hydrolyzate or condensate thereof, or the hydrolyzate or condensate of a mixture of selected compounds.

  The organic solvent is not particularly limited as long as it is an organic solvent used for this kind of application. For example, methyl alcohol, ethyl alcohol, isopropyl alcohol, propylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, etc. Can be mentioned.

  Although it does not specifically limit as water for performing the said hydrolysis-condensation reaction, It is preferable to use ion-exchange water. The water is used in an amount of 0.25 to 3 mol, preferably 0.3 to 2.5 mol, per mol of hydrolyzable group (alkoxy group or the like) of the hydrolyzable silane compound used. Is this. By using water in an amount in the above range, the uniformity of the formed coating film is not likely to be reduced, and the storage stability of the composition is less likely to be reduced.

  It does not specifically limit as said catalyst, For example, a metal chelate compound, an organic acid, an inorganic acid, an organic base, an inorganic base etc. are mentioned.

  Examples of the metal chelate compound include a titanium chelate compound, a zirconium chelate compound, and an aluminum chelate compound. Specifically, compounds described in JP 2000-356854 A can be used.

  Examples of the organic acid include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, adipic acid, sebacic acid, and gallic acid. Acid, butyric acid, meritic acid, arachidonic acid, mikimic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, benzenesulfone Examples include acids, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, pentafluoropropionic acid and the like.

  Examples of the inorganic acid include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid.

  Examples of the organic base include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicycloocrane, diazabicyclo. Nonane, diazabicycloundecene, tetramethylammonium hydroxide and the like can be mentioned.

  Examples of the inorganic base include ammonia, sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide and the like.

  Of these catalysts, metal chelate compounds, organic acids and inorganic acids are preferred. The said catalyst may be used independently and may be used in combination of 2 or more type.

  As a usage-amount of a catalyst, it is 0.001-50 mass parts normally with respect to 100 mass parts of said hydrolysable silane compounds, Preferably it is 0.01-40 mass parts.

  Further, after the hydrolysis condensation reaction, it is preferable to perform a removal treatment of reaction by-products such as lower alcohols such as methanol and ethanol. Thereby, the composition which has the outstanding applicability | paintability with respect to a board | substrate, and also has favorable storage stability can be obtained.

  The method for removing the reaction by-product is not particularly limited as long as the reaction of the hydrolyzate and / or its condensate does not proceed. For example, the boiling point of the reaction by-product is the boiling point of the organic solvent. If it is lower, it can be distilled off under reduced pressure.

<[B] Compound>
Since the composition for forming a resist underlayer film of the present invention contains a [B] compound, this [B] compound functions suitably as a curing catalyst for [A] polysiloxane, so that the resulting resist underlayer film is porous. Despite the quality shape, it is possible to exhibit excellent etching resistance during substrate processing.

[B] Examples of the alkyl group having 1 to 8 carbon atoms in R ¹ in the formula (1) representing the compound include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.

Examples of the hydroxyalkyl group having 1 to 8 carbon atoms in R ¹ include a hydroxymethyl group (—CH ₂ OH), a hydroxyethyl group (—CH ₂ CH ₂ OH), and the like.

^Examples of the b-valent organic acid anion represented by A ^b- include formic acid, acetic acid, maleic acid, fumaric acid, phthalic acid, malonic acid, succinic acid, tartaric acid, malic acid, lactic acid, citric acid, propionic acid and butanoic acid. , Pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, adipic acid, sebacic acid, butyric acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-amino Monovalent or polyvalent carboxylic acids such as benzoic acid;
Examples thereof include sulfonic acids such as p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and trifluoroethanesulfonic acid.

  Specific examples of the [B] compound include ammonium formate, ammonium maleate, ammonium fumarate, ammonium phthalate, ammonium malonate, ammonium succinate, ammonium tartrate, ammonium malate, ammonium lactate, and citric acid. Ammonium, ammonium acetate, ammonium propionate, ammonium butanoate, ammonium pentanoate, ammonium hexanoate, ammonium heptanoate, ammonium octoate, ammonium nonanoate, ammonium decanoate, ammonium oxalate, ammonium adipate, ammonium sebacate, butyric acid Ammonium, ammonium oleate, ammonium stearate, ammonium linoleate, ammonium linoleate, ammonium salicylate Bromide, ammonium benzenesulfonate, ammonium benzoate, ammonium p- aminobenzoic acid, ammonium p- toluenesulfonic acid, ammonium methanesulfonate, ammonium trifluoromethanesulfonate and ammonium salts such as ammonium trifluoroethane sulfonic acid.

  In addition, the ammonium ion of the above ammonium salt is methylammonium ion, dimethylammonium ion, trimethylammonium ion, tetramethylammonium ion, ethylammonium ion, diethylammonium ion, triethylammonium ion, tetraethylammonium ion, propylammonium ion, dipropylammonium ion Ion, tripropylammonium ion, tetrapropylammonium ion, butylammonium ion, dibutylammonium ion, tributylammonium ion, tetrabutylammonium ion, trimethylethylammonium ion, dimethyldiethylammonium ion, dimethylethylpropylammonium ion, methylethylpropylbutylammonium Ion, triethanolammonium ion, diethanolammonium ion, and also such as ammonium salts substituted triethanolammonium ions.

  Among these compounds, a tetraalkylammonium salt is preferable and a tetramethylammonium salt is more preferable from the viewpoint of low metal contamination requirements as a resist underlayer film. Examples of the tetramethylammonium salt include tetramethylammonium acetate, tetramethylammonium propionate, and tetramethylammonium maleate.

  In addition, these [B] compounds are used individually by 1 type or in combination of 2 or more types.

  Moreover, as content of a [B] compound, it is preferable that it is 0.01 to 5 mass parts with respect to 100 mass parts of silicon atoms in [A] polysiloxane, and is 0.05 to 2 mass parts. It is more preferable that the amount is not more than part by mass. If this content is less than 0.01 parts by mass, the resist underlayer film does not sufficiently cure, resulting in an insufficiently cured coating state. As a result, the etching resistance of the resulting resist underlayer film and the adhesion to the resist film are reduced. However, the workability tends to decrease. On the contrary, when the content ratio exceeds 5 parts by mass, the storage stability and the like tend to decrease.

  In addition, after dissolving or diluting a [B] compound in water or a solvent as needed, it can add to the solution of [A] polysiloxane, and can add and adjust it in a desired ratio. The timing of adding the [B] compound to the [A] polysiloxane is not particularly limited. For example, when the [A] polysiloxane is hydrolyzed, during the hydrolysis, at the end of the reaction, before and after the solvent distillation, Also good.

  Moreover, the [B] compound can produce the same effect as the case where [B] compound itself is added also by producing | generating in the synthesis | combination process of polysiloxane. That is, the [B] compound is only required to be present in a predetermined ratio in the composition, and the addition method and production method are not particularly limited. Therefore, for example, when 0.01 parts by mass of tetramethylammonium acetate is added as the [B] compound, [A] polysiloxane is synthesized by hydrolysis condensation reaction with an acetic acid catalyst, and tetramethylammonium is added to the reaction solution. Can be used as the compound [B] of the present invention by adding 0.01 parts by mass of tetramethylammonium acetate with respect to [A] polysiloxane in the reaction solution. .

<[C] Organic acid>
The composition for forming a resist underlayer film of the present invention contains a [C] organic acid, and this [C] organic acid is volatilized by heating, so that the resulting resist underlayer film can be made porous. . Since the resist underlayer film has a porous shape, the resist film laminated on the resist underlayer film surface has improved adhesion with the resist underlayer film due to the anchor effect. Therefore, according to the composition for forming a resist underlayer film, the pattern formability can be improved due to the high adhesion between the resist underlayer film and the resist film. Moreover, [C] organic acid can improve the storage stability of the said resist underlayer film composition.

  [C] The organic acid is not particularly limited. For example, formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid , Adipic acid, sebacic acid, gallic acid, butyric acid, melicic acid, arachidonic acid, mikimic acid, 2-ethylhexanoic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, Mono- or polyvalent carboxylic acids such as monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, malonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, pentafluoropropionic acid, p-toluenesulfonic acid, benzene Mention may be made of sulfonic acids such as sulfonic acids. These organic acids can be used alone or in combination of two or more.

  Among these, compounds having sublimation properties are preferable, and polyvalent carboxylic acids such as maleic acid and oxalic acid, and sulfonic acids such as methanesulfonic acid can form a uniform porous shape with respect to the obtained cured film. Is preferable.

  [C] The content of the organic acid is preferably 10 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of silicon atoms in [A] polysiloxane. [C] By setting the content of the organic acid in the above range, the porosity of the resulting resist underlayer film can be adjusted to an appropriate range, and the adhesion to the resist film and the etching resistance can be made compatible at a high level. it can.

  That is, when the content of the [C] organic acid is less than the above lower limit, a sufficient porous shape cannot be formed, and the adhesion with the resist film may not be sufficiently improved. On the other hand, when the content exceeds the above upper limit, there are too many hollow portions in the cured film, and the strength of the resulting film may be reduced.

  In addition, this [C] organic acid can be used as it is, when an organic acid is used when synthesize | combining [A] polysiloxane. [C] The organic acid can be contained in addition to or separately from the organic acid used in the synthesis of [A] polysiloxane.

<[D] Organic solvent>
The composition for forming a resist underlayer film of the present invention contains [D] an organic solvent, so that each composition is uniformly mixed and the coating property is also improved.

[D] As an organic solvent, for example,
Aliphatic carbonization such as n-pentane, iso-pentane, n-hexane, i-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, methylcyclohexane A hydrogen-based solvent;
Benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propyl benzene, iso-propyl benzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propyl benzene, n-amylnaphthalene, trimethylbenzene, etc. Aromatic hydrocarbon solvents;
Methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert- Pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n- Nonyl alcohol, 2,6-dimethylheptanol-4, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, pheno , Cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, phenyl methyl carbinol, diacetone alcohol, mono-alcohol solvents such as cresol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 A polyhydric alcohol solvent such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin;
Acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso- Ketone solvents such as butyl ketone, trimethylnonanone, cyclohexanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, and fenchon;
Ethyl ether, iso-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, 2-methoxyethanol, 2- Ethoxyethanol, ethylene glycol diethyl ether, 2-n-butoxyethanol, 2-n-hexoxyethanol, 2-phenoxyethanol, 2- (2-ethylbutoxy) ethanol, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , Diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl Ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether, 1-n-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monomethyl ether, propylene glycol monoethyl Ether solvents such as ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran;
Diethyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec -Pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl acetate Ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, propylene glycol acetate Monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, methoxytriglycol acetate, propionic acid Ethyl, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, Ester solvents such as diethyl phthalate;
Nitrogen-containing solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone;
Examples thereof include sulfur-containing solvents such as dimethyl sulfide, diethyl sulfide, thiophene, tetrahydrothiophene, dimethyl sulfoxide, sulfolane, and 1,3-propane sultone.

  Among these [D] solvents, ether solvents and ester solvents are preferable. Furthermore, among ether solvents and ester solvents, glycol solvents are particularly preferable because of their excellent film formability. Specific examples of the glycol solvent include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and the like. It is done.

  These solvents may be used alone or in combination of two or more.

<Other optional components>
The composition for forming a resist underlayer film of the present invention may contain other components as long as the effects of the present invention are not impaired. Examples of other components include an acid generator, a stabilizer, a crosslinking agent, and a surfactant.

<Acid generator>
The acid generator is a compound that generates an acid by heat treatment, radiation irradiation, or the like. Here, for example, visible light, ultraviolet light, or far ultraviolet light can be used as the radiation. Examples of the acid generator include a compound that generates an acid by heat treatment (hereinafter also referred to as “latent thermal acid generator”) and a compound that generates an acid by an ultraviolet light irradiation treatment (hereinafter “latent”). Also referred to as a “active photoacid generator”.

  The latent thermal acid generator is a compound that generates an acid by heating to 50 to 450 ° C, preferably 200 to 350 ° C. Examples of the latent thermal acid generator include onium salts such as sulfonium salts, benzothiazolium salts, ammonium salts, and phosphonium salts.

Specific examples of the sulfonium salt include 4-acetophenyldimethylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, dimethyl-4- (benzyloxycarbonyloxy) phenylsulfonium hexafluoroantimonate, dimethyl- Alkylsulfonium salts such as 4- (benzoyloxy) phenylsulfonium hexafluoroantimonate, dimethyl-4- (benzoyloxy) phenylsulfonium hexafluoroarsenate, dimethyl-3-chloro-4-acetoxyphenylsulfonium hexafluoroantimonate; benzyl -4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl-4-hydroxyphenyl Methylsulfonium hexafluorophosphate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, benzyl-4-methoxyphenylmethylsulfonium hexafluoroantimonate, benzyl-2-methyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyl- Benzylsulfonium salts such as 3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroarsenate, 4-methoxybenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, benzoin tosylate, 2-nitrobenzyl tosylate;
Dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate, 4-acetoxyphenyldibenzylsulfonium hexafluoroantimonate, dibenzyl-4-methoxyphenylsulfonium hexafluoroantimonate, dibenzyl-3 -Chloro-4-hydroxyphenylsulfonium hexafluoroarsenate, dibenzyl-3-methyl-4-hydroxy-5-tert-butylphenylsulfonium hexafluoroantimonate, benzyl-4-methoxybenzyl-4-hydroxyphenylsulfonium hexafluorophosphate Dibenzylsulfonium salts such as p-chlorobenzyl-4-hydroxyphenylmethyl Rusulfonium hexafluoroantimonate, p-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, p-chlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, p-nitrobenzyl-3-methyl-4-hydroxy Substituted benzylsulfonium such as phenylmethylsulfonium hexafluoroantimonate, 3,5-dichlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, o-chlorobenzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroantimonate salt;
Specific examples of the benzothiazonium salt include 3-benzylbenzothiazolium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluorophosphate, 3-benzylbenzothiazolium tetrafluoroborate, 3- (p- Benzylbenzothiazolium such as methoxybenzyl) benzothiazolium hexafluoroantimonate, 3-benzyl-2-methylthiobenzothiazolium hexafluoroantimonate, 3-benzyl-5-chlorobenzothiazolium hexafluoroantimonate Salt.

  Furthermore, as other latent thermal acid generators, triethylammonium 1,1,3,3,3-pentafluoro-2- (pivaloyloxy) propanesulfonate, tetrabutylammonium 1,1,3,3,3-penta Mention may also be made of ammonium salts such as fluoro-2- (pivaloyloxy) propanesulfonate and tetrabutylammonium trifluoromethanesulfonate, 2,4,4,6-tetrabromocyclohexadienone and the like.

  Among these latent thermal acid generators, 4-acetoxyphenyldimethylsulfonium hexafluoroarsenate, benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, dibenzyl-4 -Hydroxyphenylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylsulfonium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluoroantimonate, tetrabutylammonium trifluoromethanesulfonate, triethylammonium 1,1,3,3,3 -Pentafluoro-2- (pivaloyloxy) propanesulfonate is preferably used. Examples of these commercially available products include Sun-Aid SI-L85, SI-L110, SI-L145, SI-L150, SI-L160 (manufactured by Sanshin Chemical Industry Co., Ltd.).

  The latent photoacid generator is a compound that generates an acid upon irradiation with ultraviolet light of usually 1 to 100 mJ, preferably 10 to 50 mJ.

Examples of the latent photoacid generator include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium nonafluoro n-butanesulfonate, and bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate. Bis (4-tert-butylphenyl) iodonium dodecylbenzenesulfonate, bis (4-tert-butylphenyl) iodonium naphthalenesulfonate, bis (4-tert-butylphenyl) iodonium hexafluoroantimonate, bis (4-tert-butyl Phenyl) iodonium nonafluoro n-butanesulfonate, triphenylsulfonium trifluor Lomethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium nonafluoro n-butanesulfonate, (hydroxyphenyl) benzenemethylsulfonium toluenesulfonate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, Dicyclohexyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, dimethyl (2-oxocyclohexyl) sulfonium trifluoromethanesulfonate, diphenyliodonium hexafluoroantimonate, triphenylsulfonium camphorsulfonate, (4-hydroxyphenyl) benzylmethylsulfonium Toluenesulfonate, 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl -1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyl-diethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoro L-methanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-methoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- Methoxymethoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxymethoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- (1-methoxyethoxy) -1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- (2-methoxyethoxy) -1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-methyl Xyloxycarbonyloxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-ethoxycarbyloxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-n-propoxycarbonyloxy-1-naphthyltetrahydrothiophenium trifluoromethane Sulfonate, 4-iso-propoxycarbonyloxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-n-butoxyvinyloxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-tert-butoxycarbonyloxy- 1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4- (2-tetrahydrofuranyloxy) -1- Futyltetrahydrothiophenium trifluoromethanesulfonate, 4- (2-tetrahydropyranyloxy) -1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-benzyloxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 1- Onium salt photoacid generators such as (naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate;
Halogen-containing compound-based photoacid generators such as phenyl-bis (trichloromethyl) -s-triazine, methoxyphenyl-bis (trichloromethyl) -s-triazine, naphthyl-bis (trichloromethyl) -s-triazine;
1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,3,4-naphthoquinonediazide-4-sulfonic acid ester of 2,3,4,4′-tetrabenzophenone or 1 Diazo ketone compound-based photoacid generators such as 1,2-naphthoquinonediazide-5-sulfonic acid ester;
Sulfonic acid compound photoacid generators such as 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane;
Benzoin tosylate, pyrogallol tristrifluoromethanesulfonate, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1] hept-5-ene-2,3-dicarbodiimide, Examples thereof include sulfonic acid compound-based photoacid generators such as N-hydroxysuccinimide trifluoromethanesulfonate and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate.

  These acid generators can be used alone or in combination of two or more.

  It is preferable that content of the said acid generator is 0.1-20 mass parts with respect to 100 mass parts of solid content of [A] polysiloxane, More preferably, it is 0.1-10 mass parts.

<Stabilizer>
The composition for forming a resist underlayer film of the present invention may contain a stabilizer in order to improve the uniformity of the film obtained and the storage stability. Examples of the stabilizer include β-diketones, monovalent or divalent alcohols having a cyclic ether as a substituent, and cyclic ether compounds represented by the following structural formulas.

  Examples of the β-diketone include acetylacetone, 2,4-hexanedione, 2,4-heptanedione, 3,5-heptanedione, 2,4-octanedione, 3,5-octanedione, and 2,4-nonanedione. 3,5-nonanedione, 5-methyl-2,4-hexanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 1,1,1,5,5,5-hexafluoro -2,4-heptanedione and the like.

  As said cyclic ether compound, each compound represented by the following structural formula can be mentioned.

In the above formula, R ^11a is a hydrogen atom, a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms, R ¹² O— (CH ₂ CH ₂ O) _n1 — (CH ₂ ). _n2 − (where 0 ≦ n1 ≦ 5, 0 ≦ n2 ≦ 3, R ¹² is a hydrogen atom or a methyl group), or R ¹³ O— [CH (CH ₃ ) CH ₂ O] _n3 — (CH _{2) n4} - (wherein, 0 ≦ n3 ≦ 5,0 ≦ n4 ≦ 3, R 13 is a hydrogen atom or a methyl group).. R ^11b is a hydroxyl group, a linear, branched or cyclic monovalent hydrocarbon group having 1 or 2 or more hydroxyl groups, and HO— (CH ₂ CH ₂ O) _n5 — (CH ₂ ) _n6 − (where 1 ≦ n5 ≦ 5, 1 ≦ n6 ≦ 3), or HO— [CH (CH ₃ ) CH ₂ O] _n7 — (CH ₂ ) _n8 — (where 1 ≦ n7 ≦ 5 and 1 ≦ n8 ≦ 3. However, n1-n8 is an integer.

  Among these stabilizers, preferred structures are a crown ether derivative and a compound having a bicyclo ring whose bridge head position is an oxygen atom. When such a stabilizer is added, the charge of the acid is further stabilized and contributes to the stabilization of the silicon-containing compound in the composition. In addition, polyhydric alcohols such as pentaerythritol are preferable because they may show similar effects.

  In addition, the said stabilizer can be used individually by 1 type or in combination of 2 or more types. Moreover, when the sum total with said [D] organic solvent is 100 mass parts, it is preferable that the addition amount of a stabilizer is 1-50 mass parts, and it is further more preferable that it is 3-30 mass parts.

<Crosslinking agent>
Examples of the crosslinking agent that may be contained in the resist underlayer film forming composition of the present invention include an epoxy resin having a condensed polycyclic skeleton, a biphenyl skeleton, and an oxazolidone ring skeleton, and an amine-type epoxy resin having excellent curability. Can do. Here, the condensed polycyclic skeleton is a cyclic hydrocarbon formed by sharing two or more monocycles with each other, or a cyclic compound containing a hetero atom. Such a single ring may be a ring composed of a saturated bond or a ring having an unsaturated bond. The unsaturated bond is a bond selected from a carbon-carbon double bond, a carbon-nitrogen double bond, and a carbon-carbon triple bond. Specific examples of such a condensed polycyclic skeleton include naphthalene, fluorene, dicyclopentadiene, anthracene, xanthene, pyrene and the like.

  Examples of epoxy resins having a naphthalene skeleton include “Epiclon (registered trademark)” HP4032, HP4032D, HP4700, HP4770 (above, Dainippon Ink & Chemicals, Inc.), NC-7000, NC-7300 (above, Nippon Kayaku) ESN-175, ESN-360 (above, manufactured by Toto Kasei Co., Ltd.) and the like.

  Commercially available epoxy resins having a fluorene skeleton include “ONCOAT (registered trademark)” EX-1010, EX-1011, EX-1012, EX-1020, EX-1030, EX-1040, EX-1050, EX- 1051 (manufactured by Nagase Sangyo Co., Ltd.).

  Commercially available epoxy resins having a dicyclopentadiene skeleton include “Epiclon (registered trademark)” HP7200, HP7200L, HP7200H (above, manufactured by Dainippon Ink and Chemicals), Tactix558 (manufactured by Huntsman Advanced Materials) XD-1000-1L, XD-1000-2L (Nippon Kayaku Co., Ltd.), XD-1000-1L, XD-1000-2L (Nippon Kayaku Co., Ltd.), and the like. .

  Examples of commercially available epoxy resins having an anthracene skeleton include “jER (registered trademark)” YX8800 (manufactured by Japan Epoxy Resin Co., Ltd.).

  Commercially available epoxy resins having a biphenyl skeleton include “jER (registered trademark)” YX4000H, YX4000, YL6616, YL6121H, YL6640 (above, manufactured by Japan Epoxy Resin Co., Ltd.), NC3000 (Nippon Kayaku Co., Ltd.). Manufactured).

  Examples of commercially available epoxy resins having an oxazolidone ring skeleton include AER4152, XAC4151, and the like, manufactured by Asahi Kasei Epoxy Corporation. An epoxy resin having an oxazolidone ring skeleton can also be obtained, for example, by the method described in JP-A No. 2003-119253, for example, by reacting an epoxy resin with an isocyanate compound in the presence of a catalyst.

  Among these epoxy resins, an epoxy resin containing an oxazolidone ring skeleton and a naphthalene skeleton is preferable because of a good balance between elastic modulus and toughness.

  Examples of the amine type epoxy resin include tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, triglycidylaminocresol, diglycidylaniline, diglycidyltoluidine, tetraglycidylxylylenediamine, halogen substituted products thereof, and alkyl substituted products. , Alkoxy substituted products, aryl substituted products, aryloxy substituted products, hydrogenated products, and the like.

  Among these, tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, diglycidylaniline, and diglycidyltoluidine are preferable because they provide high toughness in addition to improving the balance between elastic modulus and plastic deformation ability.

  Commercially available products of the above-mentioned tetraglycidyldiaminodiphenylmethane include “Sumiepoxy (registered trademark)” ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH434L (manufactured by Tohto Kasei Co., Ltd.), “jER (registered trademark)” 604 (Japan Epoxy). Resin Co., Ltd.), “Araldide (registered trademark)” MY720, MY721 (manufactured by Huntsman Advanced Materials), and the like.

  Commercially available products of the above triglycidylaminophenol or triglycidylaminocresol include “Sumiepoxy (registered trademark)” ELM100, ELM120 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldide (registered trademark)” MY0500, MY0510, MY0600 (Huntsman). -Advanced Materials Co., Ltd.), "jER (registered trademark)" 630 (Japan Epoxy Resin Co., Ltd.) etc. can be mentioned.

  Examples of commercially available diglycidylaniline include GAN (manufactured by Nippon Kayaku Co., Ltd.).

  As a commercial item of the said diglycidyl toluidine, GOT (Nippon Kayaku Co., Ltd. product) etc. can be mentioned.

  Examples of commercially available tetraglycidylxylylenediamine and hydrogenated products thereof include “TETRAD (registered trademark)”-X, “TETRAD (registered trademark)”-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the like. it can.

  These crosslinking agents can be used alone or in combination of two or more.

  Other crosslinking agents that can be used in combination include phenol novolac type epoxy resins, cresol novolac type epoxy resins, resorcinol type epoxy resins, phenol aralkyl type epoxy resins, triphenylmethane type epoxy resins, and tetraphenylethane type epoxy resins. Etc.

  Commercially available products of the above phenol novolac type epoxy resins are “jER (registered trademark)” 152, 154 (above, manufactured by Japan Epoxy Resin Co., Ltd.), “Epiclon (registered trademark)” N-740, N-770, N- 775 (manufactured by Dainippon Ink & Chemicals, Inc.) and the like.

  Commercially available products of the above cresol novolac type epoxy resins include “Epiclon (registered trademark)” N-660, N-665, N-670, N-673, N-695 (above, manufactured by Dainippon Ink & Chemicals, Inc.). ), EOCN-1020, EOCN-102S, and EOCN-104S (manufactured by Nippon Kayaku Co., Ltd.).

  Examples of commercially available resorcinol-type epoxy resins include “Denacol (registered trademark)” EX-201 (manufactured by Nagase ChemteX Corporation).

  As a commercial item of the said triphenylmethane type epoxy resin, "Tactix" 742 (made by Huntsman Advanced Materials), EPPN-501H, EPPN-502H (above, Nippon Kayaku Co., Ltd. product) etc. are mentioned.

  Examples of the tetraphenylethane type epoxy resin include “jER (registered trademark)” 1031S (manufactured by Japan Epoxy Resin Co., Ltd.).

  As content of these crosslinking agents, 0.1-50 mass parts is preferable with respect to 100 mass parts of [A] polysiloxane, and 1-40 mass parts is more preferable. When the content is 0.1 parts by mass or less, curing as a crosslinking agent cannot be sufficiently exhibited. Conversely, when the content exceeds 50 parts by mass, the storage stability of the composition is significantly impaired.

<Surfactant>
Examples of the surfactant that may be contained in the resist underlayer film forming composition of the present invention include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and silicones. Surfactants, polyalkylene oxide surfactants, fluorine-containing surfactants, and the like. These surfactants may be used individually by 1 type, and may be used in combination of 2 or more type.

<Method for preparing resist underlayer film forming composition>
The method for preparing the composition for forming a resist underlayer film of the present invention is not particularly limited. For example, [A] polysiloxane, [B] compound, [C] organic acid, [D] organic solvent, and other as necessary. It can be obtained by mixing arbitrary components. As described above, the [B] compound and the [C] organic acid may be the same as those used in the synthesis of [A] polysiloxane, or may be used by reacting these components. Good.

  In the composition for forming a resist underlayer film of the present invention, the solid content concentration of the resin is not particularly limited, but is preferably 0.5 to 20% by mass from the viewpoint of uniform coating properties, and more preferably. Is 1 to 5% by mass.

<Resist underlayer film>
Since the resist underlayer film of the present invention is formed using the above-described resist underlayer film forming composition, it has high adhesion to the resist film, excellent etching selectivity with respect to the resist film and the substrate to be processed, and low Has reflectivity. Therefore, the resist underlayer film can be suitably used in a multilayer resist process. Further, among multilayer resist processes, it is particularly preferably used in pattern formation using a multilayer resist process in a region finer than 90 nm (ArF, ArF, F ₂ , EUV, nanoimprint in immersion exposure). it can.

Since the resist underlayer film is formed of a composition containing [C] organic acid as described above, the resist underlayer film has a porous shape by volatilization of [C] organic acid during heat curing. Yes. The degree of the porous shape can be evaluated by the BET specific surface area. The BET specific surface area of the resist underlayer film is preferably 10 m ² / g or more and 150 m ² / g or less. Since the resist underlayer film has a surface area in such a range, the adhesion with the resist film and the etching resistance can be achieved at a high level. When the BET specific surface area of the resist underlayer film is less than the above lower limit, sufficient unevenness is not formed on the surface, and the adhesion with the resist layer may not be sufficiently improved. Conversely, if the BET specific surface area exceeds the above upper limit, the internal cavity volume will increase, and the strength may be reduced.

  The film thickness of the resist underlayer film is usually 10 nm or more and 200 nm or less, and is preferably 20 nm or more and 50 nm or less in order to improve patterning properties and processing performance.

  As a specific method for producing the resist underlayer film, for example, a resist coating film or other underlayer film (antireflection film) is applied on the surface to form a resist underlayer film forming composition coating film. Examples of the method include a method in which the coating film is cured by heat treatment, or in the case where a latent photoacid generator is contained, by curing with ultraviolet light irradiation and heat treatment.

  Examples of the method for applying the resist underlayer film forming composition include known methods such as a spin coating method, a roll coating method, and a dip method. Moreover, the heating temperature of the coating film formed is 50-450 degreeC normally.

<Pattern formation method>
The pattern forming method of the present invention comprises:
(1) a step of applying the above composition for forming a resist underlayer film on a substrate to be processed to form a resist underlayer film (hereinafter also referred to as “step (1)”);
(2) a step of applying a resist composition on the resist underlayer film to form a resist film (hereinafter also referred to as “step (2)”);
(3) a step (hereinafter also referred to as “step (3)”) of exposing the resist film by selectively irradiating the resist film with radiation through a photomask;
(4) A step of developing the exposed resist film to form a resist pattern (hereinafter also referred to as “step (4)”),
(5) A step of forming a pattern by dry etching the resist underlayer film and the substrate to be processed using the resist pattern as a mask (hereinafter also referred to as “step (5)”).

  Since the pattern formation method uses the composition for forming a resist underlayer film that is excellent in adhesion to the resist film and etching selectivity as described above, a fine pattern can be efficiently formed. Hereinafter, each step will be described in detail.

<Step (1)>
In this step (1), a resist underlayer film is formed on the substrate to be processed using the resist underlayer film forming composition. Thereby, a substrate with a resist underlayer film in which a resist underlayer film is formed on a substrate to be processed can be obtained.

  As the substrate to be processed, for example, an insulating film such as silicon oxide, silicon nitride, silicon oxynitride, polysiloxane, etc., hereinafter all trade names are black diamond (manufactured by AMAT), silk (manufactured by Dow Chemical), LKD5109. An interlayer insulating film such as a wafer coated with a low dielectric insulating film (manufactured by JSR) or the like can be used. As the substrate to be processed, a patterned substrate such as a wiring course (trench) or a plug groove (via) may be used.

In addition, another lower layer film (hereinafter also referred to as “lower layer film”) different from the resist lower layer film obtained by using the composition for forming a resist lower layer film of the present invention in advance is formed on the substrate to be processed. May be. This lower layer film is a film provided with an antireflection function, coating film flatness, high etching resistance to a fluorine-based gas such as CF _{4, and the} like. This lower layer film can be formed using, for example, a material marketed under a trade name such as “NFC HM8005” (manufactured by JSR), “NFC CT08” (manufactured by JSR), and the like.

  The method of forming the lower layer film is not particularly limited. For example, a coating film formed by applying a known method such as a spin coat method on a substrate to be processed is cured by exposure and / or heating. can do. Examples of radiation used for this exposure include visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ-rays, molecular beams, and ion beams. Moreover, the temperature at the time of heating a coating film is although it does not specifically limit, It is preferable that it is 90-550 degreeC, More preferably, it is 90-450 degreeC, More preferably, it is 90-300 degreeC.

  In addition, although the film thickness of the said lower layer film is not specifically limited, It is preferable that it is 100-20,000 nm.

  Further, the method and thickness of forming the resist underlayer film in the step (1) are described in detail in the above description of <resist underlayer film>, and thus description thereof is omitted here.

<Step (2)>
In this step (2), a resist film is formed on the resist underlayer film obtained in step (1) using the resist composition.

  Examples of the resist composition used in this step (2) include a positive or negative chemically amplified resist composition containing a photoacid generator, and a positive type comprising an alkali-soluble resin and a quinonediazide-based photosensitizer. Suitable examples include resist compositions, negative resist compositions comprising an alkali-soluble resin and a crosslinking agent.

  Moreover, the solid content concentration of the resist composition is not particularly limited, but is preferably 5 to 50% by mass, for example.

  Moreover, as a resist composition, what was filtered using the filter with a hole diameter of about 0.2 micrometer can be used conveniently. In the pattern forming method of the present invention, a commercially available resist composition can be used as it is as such a resist composition.

  The method for applying the resist composition is not particularly limited, and for example, it can be applied by a conventional method such as spin coating. In addition, when apply | coating a resist composition, the quantity of the resist composition to apply | coat is adjusted so that the resist film obtained may become a predetermined film thickness.

  The resist film may be formed by volatilizing a solvent (that is, a solvent contained in the resist composition) in the coating film by pre-baking the coating film formed by applying the resist composition. it can. Although the temperature at the time of prebaking is suitably adjusted according to the kind etc. of resist composition to be used, it is preferable that it is 30-200 degreeC, More preferably, it is 50-150 degreeC. In addition, you may provide another film on the surface of this resist film.

<Step (3)>
In this step (3), the resist film obtained in step (2) is selectively irradiated with radiation through a photomask to expose the resist film.

The radiation used in this step (3) includes visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, gamma rays, molecular beams, ions, depending on the type of acid generator used in the resist composition. Although it is appropriately selected from a beam or the like, it is preferable to use far ultraviolet rays, and in particular, KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ excimer laser (wavelength 157 nm), Kr ₂ excimer laser (wavelength 147 nm) ), ArKr excimer laser (wavelength 134 nm), extreme ultraviolet light (wavelength 13 nm, etc.) and the like can be mentioned as preferred examples.

  The exposure method is not particularly limited, and can be performed in accordance with a conventionally known method for pattern formation. Further, an immersion exposure method can also be employed.

<Process (4)>
In this step (4), the resist film exposed in step (3) is developed to form a resist pattern.

  The developer used for development can be appropriately selected according to the type of resist composition used. In the case of a positive type chemically amplified resist composition or a positive type resist composition containing an alkali-soluble resin, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n -Propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo [5 4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene, and other alkaline aqueous solutions can be used. These alkaline aqueous solutions may be those obtained by adding an appropriate amount of a water-soluble organic solvent, for example, alcohols such as methanol and ethanol, and a surfactant.

  Further, in the case of a negative chemically amplified resist composition and a negative resist composition containing an alkali-soluble resin, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, etc. Inorganic alkalis, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, dimethylethanolamine and triethanolamine Alcohol amines such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline and other quaternary ammonium salts, and alkaline aqueous solutions such as pyrrole and piperidine cyclic amines can be used.

  In step (4), a predetermined resist pattern corresponding to the photomask can be formed by performing development with the developer, washing, and drying.

  In this step (4), in order to improve resolution, pattern profile, developability, etc., it is preferable to perform post-baking before development (that is, after exposure in step (3)). The post-baking temperature is appropriately adjusted according to the type of resist composition used, but is preferably 50 to 200 ° C, more preferably 80 to 150 ° C.

<Step (5)>
In this step (5), the resist underlayer film and the substrate to be processed are dry-etched using the resist pattern formed in step (4) as a mask (etching mask) to form a pattern. Note that when the substrate to be processed on which the lower layer film is formed is used, the lower layer film is also dry-etched together with the resist lower layer film and the substrate to be processed.

The dry etching can be performed using a known dry etching apparatus. The source gas during dry etching depends on the elemental composition of the object to be etched, but includes oxygen atoms such as O ₂ , CO, and CO ₂ , inert gases such as He, N ₂ , and Ar, Cl ₂ , chlorine gas such as BCl ₄ , H ₂ , NH ₃ gas, or the like can be used. In addition, these gases can also be mixed and used.

  According to the pattern forming method of the present invention, since the resist underlayer film forming composition having excellent adhesion to the resist film and etching selectivity as described above is used, the above steps (1) to (5) are appropriately performed. Thus, a fine pattern can be efficiently formed.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example. Here, “part” and “%” are based on mass unless otherwise specified.

  The determination of the solid content ratio, the weight average molecular weight (Mw), and the performance evaluation as a resist underlayer film in this example were performed by the following methods.

<Determination of solid content>
By baking 0.5 g of the siloxane resin solution at 250 ° C. for 30 minutes, the weight of the solid content relative to 0.5 g of the resin solution was measured, and the solid content of the siloxane resin solution was determined.

<Measurement of weight average molecular weight (Mw)>
Tosoh GPC columns (trade name “G2000HXL”, 2 trade names “G3000HXL”, trade name “G4000HXL” 1), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature : Measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C.

[A] Synthesis of polysiloxane (A) In each of the synthesis examples described below, polysiloxane was synthesized using hydrolyzable silane compounds of the following compounds (M-1) to (M-7). The structure of each compound is shown in the following formula.
Compound (M-1): Tetramethoxysilane Compound (M-2): Methyltrimethoxysilane Compound (M-3): Phenyltrimethoxysilane Compound (M-4): 2- (3,4-epoxycyclohexyl) ethyl Trimethoxysilane Compound (M-5): Tetraethoxysilane Compound (M-6): Tris (trimethylsilyl) silylethyltrimethoxysilane Compound (M-7): 1,4-bis (triethoxysilyl) benzene

上記式中、Ｍｅはメチル基、Ｅｔはエチル基である。

In the above formula, Me is a methyl group, and Et is an ethyl group.

Synthesis Example 1 Synthesis of Polysiloxane (A-1) 3.43 g of trifluoroacetic acid was dissolved in 4.33 g of water to prepare an aqueous trifluoroacetic acid solution. Thereafter, 8.66 g of tetramethoxysilane [formula (M-1)], 2.77 g of methyltrimethoxysilane [formula (M-2)], phenyltrimethoxysilane [formula (M-3)]. A condenser tube and a dropping funnel containing the prepared aqueous trifluoroacetic acid solution were set in a flask containing 81 g and 80 g of propylene glycol monoethyl ether. Subsequently, after heating at 60 degreeC with an oil bath, the aqueous trifluoroacetic acid solution was dripped slowly, and it was made to react at 60 degreeC for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then set in an evaporator, and methanol produced by the reaction was removed to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-1).

  The content ratio of the solid content in the obtained resin solution was 18.0% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 1,900.

[Synthesis Example 2] Synthesis of polysiloxane (A-2) 2.79 g of maleic acid was dissolved in 17.32 g of water to prepare an aqueous maleic acid solution. Thereafter, 13.85 g of tetramethoxysilane [formula (M-1)], 1.29 g of phenyltrimethoxysilane [formula (M-3)], 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane [ In the flask containing 8 g of the above formula (M-4) and 56.7 g of propylene glycol monoethyl ether, a cooling tube and a dropping funnel containing the prepared aqueous maleic acid solution were set. Subsequently, after heating at 60 degreeC with an oil bath, maleic acid aqueous solution was dripped slowly and it was made to react at 60 degreeC for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then set in an evaporator, and methanol produced by the reaction was removed to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-2).

  The content ratio of the solid content in the obtained resin solution was 17.6% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 1,500.

[Synthesis Example 3] Synthesis of polysiloxane (A-3) 0.49 g of oxalic acid was dissolved in 3.9 g of water to prepare an oxalic acid aqueous solution. Then, tetramethoxysilane [formula (M-1)] 5.92 g, phenyltrimethoxysilane [formula (M-3)] 1.1 g, tetraethoxysilane [formula (M-5)] 2.31 g , And a flask containing 86.28 g of propylene glycol monoethyl ether were set with a condenser and a dropping funnel containing the prepared aqueous oxalic acid solution. Subsequently, after heating to 60 degreeC with an oil bath, the oxalic acid aqueous solution was dripped slowly, and it was made to react at 60 degreeC for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then set in an evaporator, and methanol produced by the reaction was removed to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-3).

  The content ratio of the solid content in the obtained resin solution was 16.0% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 1,400.

[Synthesis Example 4] Synthesis of polysiloxane (A-4) In a flask containing 30.33 g of triethylamine, 104.6 g of water and 60 g of methanol, a condenser tube and tetramethoxysilane [formula (M-1) above] A dropping funnel containing 42 g, 2.97 g of phenyltrimethoxysilane [formula (M-3)], 43.75 g of tetraethoxysilane [formula (M-5)], and 60 g of methanol was set. Subsequently, after heating to 50 degreeC with an oil bath, the monomer solution was dripped slowly and it was made to react at 60 degreeC for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then added dropwise to a beaker containing 38.4 g of oxalic acid, 153 g of water, and 150 g of methanol while stirring to neutralize the flask. To this neutralized reaction solution, 300 g of butyl acetate was added to extract the polysiloxane into the butyl acetate layer and washed with water. Further, 800 g of propylene glycol monoethyl ether and 2.5 g of oxalic acid were added to the resulting butyl acetate solution (200 g) of polysiloxane and concentrated to obtain a propylene glycol monoethyl ether solution of polysiloxane. Let the solid content in this resin solution be polysiloxane (A-4).

  The content ratio of the solid content in the obtained resin solution was 17.0% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 2,300.

[Synthesis Example 5] Synthesis of polysiloxane (A-5) Into a flask containing 16.4 g of tetramethylammonium hydride, 62.8 g of water and 60 g of methanol, a cooling tube, tetramethoxysilane [the above formula (M-1) ] 31.97 g, phenyltrimethoxysilane [formula (M-3)] 2.97 g, tris (trimethylsilyl) silylethyltrimethoxysilane [formula (M-6)] 29.77 g, and methanol 60 g were added. A dropping funnel was set. Subsequently, after heating to 50 degreeC with an oil bath, the monomer solution was dripped slowly and it was made to react at 60 degreeC for 2 hours. After the completion of the reaction, the flask containing the reaction solution was allowed to cool and then added dropwise to a beaker containing 27 g of acetic acid, 90 g of water, and 90 g of methanol with stirring to perform neutralization. To this neutralized reaction solution, 300 g of butyl acetate was added to extract the polysiloxane into the butyl acetate layer and washed with water. Further, 800 g of propylene glycol monoethyl ether and 2.5 g of oxalic acid were added to the resulting butyl acetate solution (200 g) of polysiloxane and concentrated to obtain a propylene glycol monoethyl ether solution of polysiloxane. Let the solid content in this resin solution be polysiloxane (A-5).

  The content ratio of the solid content in the obtained resin solution was 18.9% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 3,600.

Synthesis Example 6 Synthesis of Polysiloxane (A-6) 0.9 g of oxalic acid was dissolved in 5.77 g of water to prepare an oxalic acid aqueous solution. Then, tetramethoxysilane [formula (M-1)] 11.54 g, methyltrimethoxysilane [formula (M-2)] 3.69 g, 1,4-bis (triethoxysilyl) benzene [formula ( M-7)] A flask containing 2.18 g and propylene glycol-1-methyl ether 75.91 g was set with a condenser and a dropping funnel containing the prepared aqueous trifluoroacetic acid solution. Subsequently, after heating to 35 degreeC with an oil bath, acid aqueous solution was dripped slowly, and it heated up at 60 degreeC after that, and was made to react for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool and then set in an evaporator, and methanol produced by the reaction was removed to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-6).

  The content ratio of the solid content in the obtained resin solution was 16.0% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 1,300.

Synthesis Example 7 Synthesis of Polysiloxane (A-7) 44.6 g of ethanol, 25.4 g of ion-exchanged water, and 9.04 g of methanesulfonic acid were charged into a 200 mL glass flask, and tetramethoxysilane [formula (M-1) above]. ] A mixture of 15.07 g, phenyltrimethoxysilane [formula (M-3)] 1.3 g, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane [formula (M-4)] 4.57 g Was added at room temperature. The product was subjected to hydrolysis and condensation for 8 hours at room temperature. Thereto, 300 mL of propylene glycol monoethyl ether was added and concentrated under reduced pressure to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-7).

  The content ratio of the solid content in the obtained resin solution was 17.3% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 2,200.

[Synthesis Example 8] Synthesis of polysiloxane (A-8) 47.6 g of isopropanol, 29.5 g of ion-exchanged water, and 3.15 g of methanesulfonic acid were charged into a 200 mL glass flask, and tetramethoxysilane [the above formula (M-1) ] 5.87 g, phenyltrimethoxysilane [above formula (M-3)] 2.03 g, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane [above formula (M-4)] 11.87 g Was added at room temperature. The temperature was raised to 60 ° C. while stirring, and the mixture was hydrolyzed and condensed at 60 ° C. for 4 hours. Thereto, 300 mL of propylene glycol monoethyl ether was added and concentrated under reduced pressure to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-8).

  The content ratio of the solid content in the obtained resin solution was 15.0% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 2,600.

Synthesis Example 9 Synthesis of Polysiloxane (A-9) 2.79 g of oxalic acid was dissolved in 17.32 g of water to prepare an aqueous oxalic acid solution. Thereafter, 13.85 g of tetramethoxysilane [formula (M-1)], 1.29 g of phenyltrimethoxysilane [formula (M-3)], 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane [ In the flask containing 8 g of the above formula (M-4)] and 56.7 g of propylene glycol monoethyl ether, a cooling tube and a dropping funnel containing the prepared aqueous oxalic acid solution were set. Subsequently, after heating to 60 degreeC with an oil bath, the oxalic acid aqueous solution was dripped slowly, and it was made to react at 60 degreeC for 2 hours. After completion of the reaction, the flask containing the reaction solution was allowed to cool, 0.01 g of tetramethylammonium hydroxide was added and set in an evaporator, and methanol produced by the reaction was removed to obtain a resin solution. Let the solid content in this resin solution be polysiloxane (A-9).

  The content ratio of the solid content in the obtained resin solution was 17.5% as a result of measurement by a firing method. Moreover, the weight average molecular weight (Mw) of solid content was 1,600.

  Table 1 shows the catalyst, the compound and the mixing ratio, the weight average molecular weight (Mw) of the obtained polysiloxane, and the solid content concentration used in each synthesis example. In Table 1, the I / II ratio is the tetramethoxysilane [(M-1) and (M-5)] and the above formulas (2) and (3) in the hydrolyzable silane compound used for the synthesis. It is a molar ratio with the represented compounds [(M-2) to (M-4), (M-6) and (M-7)].

[Example 1]
0.2 parts by mass of the compound (B-1) is added to the polysiloxane (A-1) solution obtained in Synthesis Example 1 with respect to 100 parts by mass of Si of the polysiloxane, and the solid content concentration is 2 masses. After diluting and dissolving with an additional dilution solvent (D-1) so as to be an amount%, this solution was filtered with a filter having a pore size of 0.2 μm to obtain a resist underlayer film forming composition of Example 1. The contents of the preparation are summarized in Table 2. [C] Maleic acid, an organic acid, was used in the synthesis of polysiloxane (A-1), and was included in the polysiloxane solution as it was.

[Examples 2 to 11 and Comparative Example 1] Preparation of Composition for Forming Resist Underlayer Film Examples 2 to 11 and Comparative Example 1 were the same as Example 1 except that the components were changed to the types and amounts shown in Table 2. The resist underlayer film composition of Comparative Example 1 was obtained. In Table 2, the [C] organic acid of Examples 4, 5 and 11 is the kind and amount of the organic acid added during the preparation. [C] Organic acids in other examples and comparative examples are used in the synthesis of polysiloxane and are included in the polysiloxane solution as they are.

In addition, each title in Table 2 represents each of the following compounds.
[B] Compound (B-1): Tetramethylammonium acetate (B-2): Ammonium p-toluenesulfonate (B-3): Tetramethylammonium oxalate [D] Organic solvent (D-1): Propylene glycol Monoethyl ether (D-2): Propylene glycol monomethyl ether acetate (D-3): Methanol [E] Other additives (E-1): 18-crown-6 (stabilizer represented by the following formula)

(E-2): Tetraglycidyldiaminodiphenylmethane (crosslinking agent)
(E-3): Triethylammonium 1,1,3,3,3-pentafluoro-2- (pivaloyloxy) propanesulfonate (latent thermal acid generator)
(E-4): Pentaerythritol (stabilizer)

<Evaluation>
In order to evaluate the performance of the resist underlayer film forming compositions prepared in Examples 1 to 11 and Comparative Example 1, the storage stability, substrate reflectance, BET specific surface area, pattern forming ability and etching selectivity were determined according to the following methods. evaluated. In Comparative Example 2, a SiO ₂ film formed by CVD is used as the resist underlayer film. The results are summarized in Table 3.

<Characteristic evaluation of resist underlayer>
(1) Storage stability of the composition solution The prepared composition is applied to the surface of a silicon wafer using a spin coater under the conditions of 2,000 rpm and 20 seconds, and then on a hot plate at 250 ° C. A resist underlayer film was formed by drying for 60 seconds. About the obtained resist underlayer film, the film thickness was measured at 50 points using an optical film thickness meter (manufactured by KLA-Tencor, “UV-1280SE”), and the average film thickness (initial film thickness = T ₀ ). Further, using the composition after two months at a temperature of 30 ° C., a silicon-containing film was formed in the same manner as described above, the film thickness was measured, and the average film thickness (film thickness after storage = T) was obtained. It was.

Then, the difference (T−T ₀ ) between the initial film thickness T ₀ and the post-storage film thickness T is obtained, and the ratio [(T−T ₀ ) / T ₀ ] of the difference with respect to the average film thickness T ₀ is obtained. The film thickness change rate was calculated and evaluated. If the value is 5% or less, it is good.

(2) Pattern forming ability A composition for forming a lower layer film (trade name “NFC HM8006”, manufactured by JSR Corporation) is applied on a silicon wafer by a spin coater and dried on a hot plate at 250 ° C. for 60 seconds. Thus, a lower layer film having a thickness of 300 nm was formed.

  Thereafter, a resist underlayer film forming composition was applied onto the underlayer film by a spin coater and baked on a hot plate at 200 ° C. for 60 seconds to form a resist underlayer film (dry film thickness = 35 nm).

Next, a resist material “ARX2014J, manufactured by JSR Corporation” was applied onto the resist underlayer film, and dried at 90 ° C. for 60 seconds. The resist film thickness at this time was controlled to 100 nm. Further, a liquid immersion upper layer film material “NFC TCX091-7, manufactured by JSR Co., Ltd.) was applied onto the formed resist film and dried for 60 seconds at 90 ° C. The film thickness of the liquid immersion upper layer was 30 nm. Thereafter, using an ArF excimer laser irradiation apparatus “S610C, manufactured by Nikon Corporation”, the substrate was irradiated under the condition of 16 mJ / cm ² , and then the substrate was heated for 60 seconds at 115 ° C. Next, 2.38% The resist film was developed with an aqueous tetramethylammonium hydroxide solution for 30 seconds, and a resist pattern was formed using a mask for forming a 50 nm line and space pattern.

When the resist pattern formed on the substrate as described above is observed with a scanning electron microscope (SEM), the resist pattern does not develop and peel off, and the bottom of the resist pattern has a rectangular shape. The case where there was “◯” and peeling or shape abnormality was evaluated as “×”. In addition, the pattern width of the minimum pattern remaining when exposed and developed under the condition of 18 mJ / cm ² is defined as the minimum collapse dimension, and the smaller this value, the better the adhesion between the resist film and the resist underlayer film. means.

(3) Substrate reflectance On a silicon wafer, in order from the bottom, a 300 nm underlayer film (trade name “NFC HM8006”, manufactured by JSR Corporation, film thickness = 300 nm), a resist underlayer film (film thickness = 35 nm), resist Multi-layer consisting of materials (trade name “ARX2014J”, manufactured by JSR Corporation, film thickness = 100 nm), and immersion upper layer film material (trade name “NFC TCX091-7”, manufactured by JSR Corporation, film thickness = 30 nm) The substrate reflectance (unit:%) when the resist film is exposed at S610C, illumination conditions: NA = 1.35, DipoleX, outer sigma 0.97, Inner Sigma 0.77, Blade angle 35 °) is KLA-Tencor. The calculation was performed using a lithography simulation software PROLITH X3.1 manufactured by the company. If it is 1% or less, it is good. In addition, each film | membrane was shape | molded by the method used by said (2) pattern formation ability.

(4) BET specific surface area From a bottom layer film (trade name “NFC HM8006”, manufactured by JSR Corporation, film thickness = 300 nm) and resist layer film (film thickness = 35 nm) in order from the bottom on a silicon wafer. The BET specific surface area (unit: m ² / g) was determined by using an automatic specific surface area measuring apparatus (trade name “Gemini V2380”, manufactured by Shimadzu Corporation) using nitrogen gas as an adsorbed gas. In addition, each film | membrane was shape | molded by the method used by said (2) pattern formation ability. The artificial zeolite used as the standard substance had a BET specific surface area of 45.5 m ² / g.

(5) Processing performance (5-1) Selectivity ratio to resist A resist material “ARX2014J, manufactured by JSR Co., Ltd.) was applied onto a silicon wafer and dried at 90 ° C. for 60 seconds to form a resist film having a thickness of 100 nm. A resist underlayer film composition was applied to another silicon wafer, and dried at 200 ° C. for 60 seconds to form a resist underlayer film having a thickness of 50 nm.These two types of wafers were then subjected to dry etching equipment TE manufactured by Tokyo Electron Ltd. Etching was performed using -8500 P, and the etching rate per processing time was calculated from the difference in film thickness before and after the treatment.The value obtained by dividing the etching rate of the resist underlayer film by the etching rate of the resist film was used as the selectivity to the resist film. If this ratio is 10 or more, it is good.

Etching conditions are as shown below.
Chamber pressure 40.0Pa
RF power 500W
Gap 9mm
CHF ₃ gas flow rate 20mL / min
CF ₄ gas flow rate 60mL / min
Ar gas flow rate 200mL / min
Time 30sec

(5-2) Selection ratio with respect to base material (substrate to be processed) A composition for forming a lower layer film (trade name “NFC HM8006, manufactured by JSR Corporation”) was applied on a silicon wafer by a spin coater, and hot at 250 ° C. An underlayer film having a thickness of 300 nm was formed by drying on a plate for 60 seconds, and a resist underlayer film forming composition was applied to another silicon wafer and dried at 200 ° C. for 60 seconds to form a resist underlayer film having a thickness of 50 nm. These two types of wafers were etched using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Co., Ltd., and the etching rate per processing time was calculated from the difference in film thickness before and after the processing. A value obtained by dividing the etching rate by the etching rate of the resist underlayer film was used as a selection ratio with respect to the base material. .

Etching conditions are as shown below.
Chamber pressure 60.0Pa
RF power 300W
Ar gas flow rate 40mL / min
O ₂ gas flow rate 60mL / min
Gap 9mm
Time 20sec

  As shown from the results in Table 3, it was found that the resist underlayer film forming compositions of Examples 1 to 11 showed good results in any evaluation and exhibited excellent performance. In addition, it turned out from the comparison with Example 10 and 11 and another Example that the more superior performance is expressed by adjusting the quantity of a [B] compound and a [C] organic acid.

The composition for forming a resist underlayer film of the present invention can be suitably used as a composition for forming a resist underlayer film in a multilayer resist process.

Claims (6)

[A] polysiloxane,
[B] a compound represented by the following formula (1),
[C] an organic acid, and [D] an organic solvent seen including,
[A] A composition for forming a resist underlayer film, wherein the content of [C] organic acid is 10 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of silicon atoms contained in polysiloxane .

(In Formula (1), each R ¹ is independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms. A ^b- is a b-valent organic acid. An anion, b is 1 or 2)   [A] The composition for forming a resist underlayer film according to claim 1, wherein the content of the [B] compound is from 0.01 parts by mass to 5 parts by mass with respect to 100 parts by mass of silicon atoms contained in the polysiloxane. [A] The polysiloxane is derived from at least one compound selected from the group consisting of a tetraalkoxysilane-derived structural unit, a compound represented by the following formula (2), and a compound represented by the following formula (3). The composition for forming a resist underlayer film according to claim 1, comprising a structural unit.

(In Formula (2), R ² is a single bond, an oxygen atom, a d-valent C 1-6 linear or branched aliphatic saturated hydrocarbon group, a d-valent aromatic hydrocarbon group, or d. the valence of the heterocyclic group, the aromatic hydrocarbon group, and some or. more R ³ which may be substituted in all of the hydrogen atoms of the heterocyclic group are each independently a monovalent A plurality of X's are each independently a single bond, a methylene group, a linear or branched alkylene group having 2 to 5 carbon atoms or a phenylene group, and the methylene group, alkylene group and phenylene group A part or all of the hydrogen atoms in the group may be substituted, and each of the plurality of Y is independently a halogen atom or —OR ^6. R ⁶ is a monovalent organic group, c is , the .d an integer of 0 to 2, is 2 or 3. However, if d is 3, R But not be a single bond or oxygen atom.
In formula (3), R ⁴ and R ⁵ are each independently a monovalent organic group. ) A resist underlayer film formed using the resist underlayer film forming composition according to claim 1, 2 or 3 . The resist underlayer film according to claim 4 , wherein the BET specific surface area is 10 m ² / g or more and 150 m ² / g or less. (1) A step of applying a composition for forming a resist underlayer film according to claim 1 , claim 2 or claim 3 on a substrate to be processed to form a resist underlayer film;
(2) applying a resist composition on the resist underlayer film to form a resist film;
(3) exposing the resist film by selectively irradiating the resist film with radiation through a photomask;
(4) developing the exposed resist film to form a resist pattern;
(5) A pattern forming method comprising: forming a pattern by dry etching the resist underlayer film and the substrate to be processed using the resist pattern as a mask.