JP6281490B2 - Resist underlayer film forming resin composition, resist underlayer film, method for forming the same, and pattern forming method - Google Patents

Description

  The present invention relates to a resist underlayer film forming resin composition, a resist underlayer film and a method for forming the resist underlayer film, a pattern forming method, a crosslinking agent, and a compound.

  In the manufacture of semiconductor devices, a multilayer resist process is used to obtain a high degree of integration. In this process, first, a resist underlayer film forming resin composition is applied to the upper surface side of the substrate to form a resist underlayer film, and the resist composition is applied to the upper surface side of the resist underlayer film to form a resist film. Then, the resist film is exposed through a mask pattern with a reduction projection exposure apparatus (stepper) or the like, and developed with an appropriate developer to form a resist pattern. Then, the resist underlayer film is dry-etched using the resist pattern as a mask, and the substrate is further dry-etched using the obtained resist underlayer film pattern as a mask, whereby a desired pattern can be formed on the substrate. The resist underlayer film used in such a multilayer resist process is required to have general characteristics such as etching resistance and optical characteristics.

  In recent years, in order to further increase the degree of integration, pattern miniaturization has further progressed. In the multilayer resist process described above, there are various structures and functional groups contained in the polymer and the like contained in the resin composition for forming a resist underlayer film. (See JP 2004-177668 A). In particular, even if the pattern is further miniaturized, it is required that the resist underlayer film pattern can have a good shape. For this reason, the resist underlayer film to be formed is required to have high bending resistance.

  Recently, a multilayer resist process in which a hard mask is formed on a resist underlayer film by a CVD method has been studied. Specifically, a process of forming a resist underlayer film and producing an inorganic hard mask intermediate layer as a resist intermediate layer thereon by a CVD method has been studied. When the inorganic hard mask intermediate layer is formed by the CVD method, it is necessary to heat the substrate at a minimum of 300 ° C., usually 400 ° C., particularly in forming a nitride film.

JP 2004-177668 A

  However, due to the organic material as the main component, the resist underlayer film using the above conventional composition has difficulty in heat resistance, and due to the low heat resistance, the resist underlayer film component is heated by the resist underlayer film formation. May sublimate, and the sublimated components may reattach to the substrate and deteriorate the manufacturing yield of semiconductor devices.

  The present invention has been made based on the circumstances as described above, and its purpose is to sufficiently satisfy general characteristics such as etching resistance, and in addition, a resist underlayer film having high heat resistance and high bending resistance can be formed. A resist underlayer film forming resin composition, a resist underlayer film using the composition, a method for forming the resist underlayer film, and a pattern forming method using the composition are provided.

  As a result of intensive studies, the present inventors have found that the above-described object can be achieved by a resin composition for forming a resist underlayer film using a crosslinking agent having a specific structure, and the present invention has been completed.

（式（ｉ）中、
Ｘは、カルボニル基又はスルホニル基である。
Ｑは、１価の複素芳香族基又は−ＯＲ^１である。Ｒ^１は、炭素数１〜３０の１価の有機基である。
Ａｒは、芳香族炭化水素基又は複素芳香族基である。
ｎは、１〜８の整数である。ｎが２以上の場合、複数のＸ及びＱはそれぞれ同一でも異なっていてもよい。）
［２］上記架橋剤が、下記式（ｂ１）で表される化合物及び下記式（ｂ２）で表される化合物からなる群より選ばれる少なくとも１種である上記［１］に記載のレジスト下層膜形成用樹脂組成物。

（式（ｂ１）中、
Ｘ及びＱは、上記式（ｉ）と同義である。
Ａｒ^１は、（ｎ_１＋ｎ_２＋１）価の芳香族炭化水素基又は（ｎ_１＋ｎ_２＋１）価の複素芳香族基である。
Ａｒ^２は、（ｎ_３＋ｎ_４＋１）価の芳香族炭化水素基又は（ｎ_３＋ｎ_４＋１）価の複素芳香族基である。
Ｒ^２は、それぞれ独立して、ヒドロキシ基又は置換若しくは非置換の炭素数１〜３０の１価の炭化水素基である。
Ｒ^３は、単結合、炭素数１〜３０の２価の炭化水素基、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−、−ＣＳ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＮＲ−又はこれらの基を組み合わせた２価の基である。Ｒは、水素原子又は炭素数１〜３０の炭化水素基である。
Ｒ^４は、単結合、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−Ｏ−、−ＣＳ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＮＲ−、炭素数１〜３０の（ｎ_５＋１）価の炭化水素基又はこれらの基を組み合わせた（ｎ_５＋１）価の基である。Ｒは、水素原子又は炭素数１〜３０の炭化水素基である。
ｎ_１は、１〜７の整数である。ｎ_２は、０〜６の整数である。但し、ｎ_１＋ｎ_２は、７以下である。
ｎ_３は、１〜７の整数である。ｎ_４は、０〜６の整数である。但し、ｎ_３＋ｎ_４は、７以下である。
ｎ_５は、１〜５の整数である。
Ａｒ^２、Ｒ^２、Ｒ^３、Ｘ及びＱがそれぞれ複数の場合、複数のＡｒ^２、Ｒ^２、Ｒ^３、Ｘ及びＱはそれぞれ同一でも異なっていてもよい。）

（式（ｂ２）中、
Ｘ及びＱは、上記式（ｉ）と同義である。
Ａｒ^３は、（ｎ_６＋ｎ_７）価の芳香族炭化水素基又は（ｎ_６＋ｎ_７）価の複素芳香族基である。
Ｒ^２は、ヒドロキシ基又は置換若しくは非置換の炭素数１〜３０の１価の炭化水素基である。
ｎ_６は、１〜８の整数である。ｎ_７は、０〜７の整数である。但し、ｎ_６＋ｎ_７は、８以下である。
Ｒ^２、Ｘ及びＱがそれぞれ複数の場合、複数のＲ^２、Ｘ及びＱはそれぞれ同一でも異なっていてもよい。）
［３］上記式（ｉ）におけるＱのＲ^１が、下記式（ｉｉ）〜（ｉｖ）のいずれかで表される上記［１］に記載のレジスト下層膜形成用樹脂組成物。

（式（ｉｉ）中、Ｒ^５及びＲ^６は、それぞれ独立して、炭素数１〜２０の１価の有機基である。但し、上記Ｒ^５とＲ^６とが互いに結合して、それらが結合している炭素原子と共に環構造を形成してもよい。）

（式（ｉｉｉ）中、Ｒ^７及びＲ^８は、それぞれ独立して、炭素数１〜２０の１価の有機基である。但し、上記Ｒ^７とＲ^８とが互いに結合して、それらが結合している窒素原子と共に環構造を形成してもよい。）

（式（ｉｖ）中、Ｒ^９は、電子求引性基を含む炭素数１〜２０の１価の有機基である。）
［４］上記式（ｉ）におけるＱのＲ^１が、上記式（ｉｖ）で表される上記［３］に記載のレジスト下層膜形成用樹脂組成物。
［５］上記樹脂が、ノボラック樹脂、レゾール樹脂、アセナフチレン系樹脂、スチレン系樹脂及びポリアリーレン系樹脂から選ばれる少なくとも１種である上記［１］に記載のレジスト下層膜形成用樹脂組成物。
［６］溶媒をさらに含有する上記［１］に記載のレジスト下層膜形成用樹脂組成物。
［７］上記［１］に記載のレジスト下層膜形成用樹脂組成物により形成されたレジスト下層膜。
［８］上記［１］に記載のレジスト下層膜形成用樹脂組成物で基板の上面側に塗膜を形成する工程と、上記塗膜と上記基板とを加熱する工程とを備えるレジスト下層膜の形成方法。
［９］基板の上面側に、上記［１］に記載のレジスト下層膜形成用樹脂組成物でレジスト下層膜を形成する工程と、上記レジスト下層膜の上面側にレジストパターンを形成する工程と、上記レジストパターンをマスクとし、上記レジスト下層膜及び上記基板を順次エッチングする工程とを備えるパターン形成方法。
［１０］上記式（ｉ）で表される部分構造を有する架橋剤。
［１１］上記式（ｂ１）で表される化合物。
［１２］上記式（ｂ２）で表される化合物。The present invention is as follows.
[1] A resin containing an aromatic ring (hereinafter also referred to as “resin (A)”) and a crosslinking agent having a partial structure represented by the following formula (i) (hereinafter also referred to as “crosslinking agent (B)”) And a resin composition for forming a resist underlayer film.

(In the formula (i),
X is a carbonyl group or a sulfonyl group.
Q is a monovalent heteroaromatic group or —OR ¹ . R ¹ is a monovalent organic group having 1 to 30 carbon atoms.
Ar is an aromatic hydrocarbon group or a heteroaromatic group.
n is an integer of 1-8. When n is 2 or more, the plurality of X and Q may be the same or different. )
[2] The resist underlayer film according to [1], wherein the crosslinking agent is at least one selected from the group consisting of a compound represented by the following formula (b1) and a compound represented by the following formula (b2). Resin composition for forming.

(In the formula (b1),
X and Q are synonymous with the above formula (i).
Ar ¹ is a (n ₁ + n ₂ +1) -valent aromatic hydrocarbon group or a (n ₁ + n ₂ +1) -valent heteroaromatic group.
Ar ² is an (n ₃ + n ₄ +1) -valent aromatic hydrocarbon group or a (n ₃ + n ₄ +1) -valent heteroaromatic group.
R ² is each independently a hydroxy group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.
R ³ represents a single bond, a divalent hydrocarbon group having 1 to 30 carbon atoms, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO. _2- , -NR- or a divalent group in which these groups are combined. R is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
R ⁴ is a single bond, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ —, —NR—, or C 1-30. It is a (n ₅ +1) valent hydrocarbon group or a (n ₅ +1) valent group obtained by combining these groups. R is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
n ₁ is an integer of 1 to 7. n ₂ is an integer of 0 to 6. However, n ₁ + n ₂ is 7 or less.
n ₃ is an integer of 1 to 7. n ₄ is an integer of 0 to 6. However, n ₃ + n ₄ is 7 or less.
n ₅ is an integer of 1 to 5.
^{Ar 2, R 2, R 3} , if X and Q are a plurality each of a plurality of ^{Ar 2, R 2, R 3} , X and Q may each be the same or different. )

(In the formula (b2),
X and Q are synonymous with the above formula (i).
Ar ³ is an (n ₆ + n ₇ ) -valent aromatic hydrocarbon group or a (n ₆ + n ₇ ) -valent heteroaromatic group.
R ² is a hydroxy group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.
n ₆ represents an integer of 1 to 8. n ₇ is an integer of 0 to 7. However, n ₆ + n ₇ is 8 or less.
R ^2, if ^X and Q are a plurality each of the plurality of R ^2, X and Q may be the same as or different from each other. )
[3] The resin composition for forming a resist underlayer film according to the above [1], wherein R ¹ of Q in the formula (i) is represented by any one of the following formulas (ii) to (iv).

(In formula (ii), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms, provided that R ⁵ and R ⁶ are bonded to each other, and (A ring structure may be formed with the carbon atom to which it is bonded.)

(In Formula (iii), R ⁷ and R ⁸ are each independently a monovalent organic group having 1 to 20 carbon atoms, provided that R ⁷ and R ⁸ are bonded to each other, and (A ring structure may be formed together with the nitrogen atom bonded thereto.)

(In formula (iv), R ⁹ is a monovalent organic group having 1 to 20 carbon atoms including an electron withdrawing group.)
[4] The resin composition for forming a resist underlayer film according to the above [3], wherein R ¹ of Q in the formula (i) is represented by the formula (iv).
[5] The resin composition for forming a resist underlayer film according to [1], wherein the resin is at least one selected from a novolak resin, a resole resin, an acenaphthylene resin, a styrene resin, and a polyarylene resin.
[6] The resin composition for forming a resist underlayer film according to [1], further including a solvent.
[7] A resist underlayer film formed from the resin composition for forming a resist underlayer film according to [1].
[8] A resist underlayer film comprising: a step of forming a coating film on the upper surface side of a substrate with the resin composition for forming a resist underlayer film according to [1] above; and a step of heating the coating film and the substrate. Forming method.
[9] A step of forming a resist underlayer film on the upper surface side of the substrate with the resin composition for forming a resist underlayer film according to [1], a step of forming a resist pattern on the upper surface side of the resist underlayer film, And a step of sequentially etching the resist underlayer film and the substrate using the resist pattern as a mask.
[10] A crosslinking agent having a partial structure represented by the above formula (i).
[11] A compound represented by the formula (b1).
[12] A compound represented by the formula (b2).

  According to the resin composition for forming a resist underlayer film of the present invention, it is possible to form a resist underlayer film that sufficiently satisfies general characteristics such as etching resistance and has high heat resistance and high bending resistance. Accordingly, the resist underlayer film forming resin composition, the resist underlayer film and its forming method, the pattern forming method, the cross-linking agent, and the compound are a pattern forming process using a multilayer resist process in a semiconductor device in which further miniaturization of the pattern proceeds. Can be suitably used.

  Hereinafter, the present invention will be described in detail.

<Resin underlayer film forming resin composition>
The resist underlayer film forming resin composition of the present invention contains a resin (A) and a crosslinking agent (B).

[Resin (A)]
Examples of the resin (A) include novolak resins, resol resins, acenaphthylene resins, styrene resins, and polyarylene resins.

  Examples of the novolak resin include phenol, cresol, xylenol, resorcinol, bisphenol A, p-tert-butylphenol, p-octylphenol, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4- Phenols such as hydroxyphenyl) fluorene and 9,9-bis (4-hydroxynaphthalene) fluorene; groups consisting of naphthols such as α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene and 2,7-dihydroxynaphthalene 1 type or 2 or more types of phenolic compounds selected from more than 1 type or 2 or more types of aldehydes selected from the group which consists of aldehyde sources, such as formaldehyde; paraformaldehyde, trioxane, etc. using an acidic catalyst Obtained resin, etc. Is mentioned.

  Examples of such a resin include a polymer having a repeating unit represented by the following formula (a).

In the above formula (a1),
Ar ¹⁰ is a (m ₁₁ + m ₁₂ + m ₁₃ +1) -valent aromatic group.
R ¹⁰ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms, or —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ —. And a monovalent group in which at least one selected from the group consisting of -NR- and a monovalent hydrocarbon group having 1 to 10 carbon atoms are combined. R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
Ar ¹¹ is a single bond or a divalent aromatic group.
R ¹¹ represents a single bond, a divalent hydrocarbon group having 1 to 10 carbon atoms, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO. _2- , -NR- or a divalent group in which these groups are combined. R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
Z ⁰ is a single bond, a divalent hydrocarbon group having 1 to 10 carbon atoms, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO. _2- , -NR- or a divalent group in which these groups are combined. R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
m ₁₁ represents the number of bonds in which Z ⁰ is bonded to Ar ¹⁰ and is an integer of 1 to 6. m ₁₂ is an integer of 0 to 6. m ₁₃ is an integer of 0 to 6. m ₁₄ is an integer of 0-2. ^{R 10, Ar 11,} R 11 and ^Z when ⁰ is plural respective plurality of ^{R 10,} Ar ^{11, R} 11 and ^{Z 0} may have respectively the same or different. * Represents a bond.

In addition, the hydrocarbon group in R ¹⁰ and R ¹¹ in the above formula (a1) may have a substituent. Examples of the substituent include a halogen atom and a hydroxy group. As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.

Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ¹⁰ in the formula (a1) include, for example, a monovalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, Examples thereof include a monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms, or a monovalent group obtained by combining these.

  Examples of the monovalent linear or branched hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methylpropyl. Group, 1-methylpropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group and the like.

  Examples of the monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.

  Examples of the monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group.

It consists of —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ — and —NR— represented by R ¹⁰ in the above formula (a1). Examples of the monovalent group in which at least one selected from the group and a monovalent hydrocarbon group having 1 to 10 carbon atoms are combined include, for example, an alkoxy group having 1 to 10 carbon atoms and an alkoxycarbonyl group having 2 to 10 carbon atoms. Group, a glycidyl ether group, an alkyl glycidyl ether group (however, the alkyl moiety has 1 to 10 carbon atoms).

Examples of the divalent hydrocarbon group having 1 to 10 carbon atoms represented by R ¹¹ and Z ⁰ in the above formula (a1) include, for example, a divalent linear or branched hydrocarbon having 1 to 10 carbon atoms. A divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 10 carbon atoms, or a divalent group obtained by combining these groups.

  As said C1-C10 bivalent linear or branched hydrocarbon group, a C2-C8 linear or branched alkylene group is preferable, an ethylene group, a propylene group, a butylene group, A hexylene group and an octylene group are more preferable.

  The divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms is preferably an alicyclic hydrocarbon group having 5 to 10 carbon atoms, and the monocyclic alicyclic hydrocarbon group is a cyclopentylene group. The cyclohexylene group is more preferably a norbornanediyl group or an adamantanediyl group as the polycyclic alicyclic hydrocarbon group.

  The divalent aromatic hydrocarbon group having 6 to 10 carbon atoms is preferably a phenylene group, a tolylene group or a naphthylene group.

Examples of the (m ₁₁ + m ₁₂ + m ₁₃ +1) -valent aromatic group represented by Ar ¹⁰ include a benzene aromatic ring such as a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, a fluorenylidene biphenyl ring; a furan ring, A compound having a heteroaromatic ring such as a pyrrole ring, a thiophene ring, a phosphole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring or a triazine ring on an aromatic ring ( m ₁₁ + m ₁₂ + m ₁₃ +1) groups and the like excluding hydrogen atoms.

Examples of the divalent aromatic group represented by Ar ¹¹ include benzene aromatic rings such as benzene ring, naphthalene ring, anthracene ring, indene ring, fluorenylidene biphenyl ring; furan ring, pyrrole ring, thiophene ring, phosphorol ring A group in which two hydrogen atoms on an aromatic ring are removed from a compound having a heteroaromatic ring such as a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring or a triazine ring Etc.

  Examples of the resol resin include resins obtained by reacting the above-mentioned phenolic compounds with the above-mentioned aldehydes using an alkaline catalyst.

  As said acenaphthylene-type resin, the polymer etc. which have a repeating unit represented by a following formula (a2) are mentioned, for example.

In the above formula (a2),
R ²⁰ and R ²¹ are each independently a hydrogen atom, a halogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or —CO—, —COO—, —OCO—, —O—, —CS. A monovalent group in which at least one selected from the group consisting of —, —S—, —SO—, —SO ₂ — and —NR— is combined with a monovalent hydrocarbon group having 1 to 10 carbon atoms. . R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
R ²² is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms.
m ₂₁ is an integer of 0 to 6. If R ²² is plural, plural R ²² may be the same or different.

Examples of the group represented by R ²⁰ and R ²¹ in the above formula (a2) include the same groups as those exemplified as R ^{10 in the} above formula (a1).

Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms represented by R ²² in the formula (a2) include a monovalent linear or branched hydrocarbon group having 1 to 12 carbon atoms and 3 carbon atoms. A -12 alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or a combination thereof.

  Examples of the monovalent linear or branched hydrocarbon group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methylpropyl. Group, 1-methylpropyl group, t-butyl group, pentyl group, hexyl group, octyl group, dodecyl group and the like.

  Examples of the monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.

  Examples of the monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group.

  The acenaphthylene-based resin can be obtained by polymerizing a compound having an acenaphthylene skeleton in an appropriate polymerization form such as bulk polymerization or solution polymerization by radical polymerization, anionic polymerization, cationic polymerization, or the like. Further, as described in paragraphs [0008] to [0031] of JP-A No. 2002-296789, it is obtained by reacting a polymer of a compound having an acenaphthylene skeleton with paraformaldehyde under acidic conditions. You can also.

  As said styrenic resin, the polymer etc. which contain the repeating unit represented by a following formula (a3) are mentioned, for example.

In the above formula (a3),
R ³⁰ each independently represents a halogen atom, a hydroxy group, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or —CO—, —COO—, —OCO—, —O—, —CS—, — S -, - SO -, - is and at least one and a divalent group comprising a combination of a monovalent hydrocarbon group having 1 to 10 carbon atoms chosen from the group consisting of -NR- - SO _2. R is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
m ₃₁ is an integer from 0 to 5. If R ³⁰ is plural, plural R ³⁰ may be the same or different.

Examples of the group represented by R ³⁰ in the above formula (a3) include the same groups as those exemplified as R ^{10 in the} above formula (a1).

  The styrenic resin may have other repeating units in addition to the repeating unit represented by the formula (a3).

  The monomer that gives the other repeating unit is not particularly limited, and examples thereof include compounds having various polymerizable unsaturated bonds. Examples of such a compound having a polymerizable unsaturated bond include (meth) styrene monomers such as α-methylstyrene, (meth) acrylonitrile, (meth) acrylic acid, methyl (meth) acrylate, and the like. Acrylic monomers such as acrylic acid ester and (meth) acrylamide; vinyl ethers such as ethyl vinyl ether, maleic anhydride, vinyl acetate, vinyl pyridine and the like.

  As a content rate of the other repeating unit in the said styrene resin, less than 50 mol% is preferable with respect to all the structural units which comprise a styrene resin, and less than 40 mol% is further more preferable.

  The degree of polymerization of the styrenic resin, that is, the total number of repeating units represented by the formula (a3) and other repeating units is preferably 5 or more and 200 or less, and more preferably 10 or more and 150 or less.

  As the precursor polymer for forming the styrene resin (particularly, a polyvinylphenol polymer), a commercially available product may be used. For example, “Marcalinker M” (poly-p-vinylphenol manufactured by Maruzen Petrochemical Co., Ltd.). ), “Linker MB” (brominated poly-p-vinylphenol), “Linker CMM” (p-vinylphenol / methyl methacrylate copolymer), “Linker CHM” (p-vinylphenol / 2-hydroxy methacrylate) Ethyl copolymer), “linker CST” (p-vinylphenol / styrene copolymer), and the like.

  Examples of the polyarylene resin include polyarylene ether, polyarylene sulfide, polyarylene ether sulfone, and polyarylene ether ketone.

  The polystyrene-converted weight average molecular weight (hereinafter also referred to as “Mw”) measured by gel permeation chromatography (GPC) of the resin (A) is preferably 500 to 100,000, more preferably 1,000 to 50, 000, more preferably 1,200 to 40,000.

  The ratio (Mw / Mn) between the Mw of the resin (A) and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) measured by GPC is usually 1 to 5, preferably 1 to 3. .

  The resist underlayer film forming resin composition may contain only one type of resin (A), or may contain two or more types.

[Crosslinking agent (B)]
The crosslinking agent (B) has a partial structure represented by the following formula (i). That is, the structural formula of the compound constituting the crosslinking agent (B) includes at least the structure represented by the above formula (i). In addition, this crosslinking agent (B) may be a compound having a structure represented by the above formula (i).

  In the resist underlayer film forming resin composition, it is speculated that the crosslinking agent (B) reacts with the resin (A) to generate a carbonyl group or a sulfonyl group sandwiched between aromatic rings. A carbonyl group or a sulfonyl group can contribute to high heat resistance. As a result, it is considered that the formed resist underlayer film sufficiently satisfies general characteristics such as etching resistance, has high bending resistance, and improves heat resistance.

In the above formula (i),
X is a carbonyl group or a sulfonyl group.
Q is a monovalent heteroaromatic group or —OR ¹ . R ¹ is a monovalent organic group having 1 to 30 carbon atoms.
Ar is an aromatic hydrocarbon group or a heteroaromatic group.
n is an integer of 1-8. When n is 2 or more, X and Q may be the same or different.

  Examples of the monovalent heteroaromatic group represented by Q in the above formula (i) include heteroaromatic groups such as pyrrole ring, imidazole ring, pyrazole ring, pyrazine ring, indole ring, isoindole ring, benzimidazole ring, and purine ring. And a group obtained by removing one hydrogen atom on a heteroaromatic ring from a compound containing a ring. Among these heteroaromatic groups, a heteroaromatic group having 3 to 30 carbon atoms is preferable, a group including a heteroaromatic ring having an NH group is more preferable, and a group obtained by removing a hydrogen atom on a nitrogen atom is more preferable.

The monovalent organic group represented by R ¹ in the formula (i) is not particularly limited, but a group represented by any one of the following formulas (ii) to (iv) is preferable.

In the above formula (ii), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms. However, R ⁵ and R ⁶ may be bonded to each other to form a ring structure together with the carbon atom to which they are bonded.

In the above formula (iii), R ⁷ and R ⁸ are each independently a monovalent organic group having 1 to 20 carbon atoms. However, R ⁷ and R ⁸ may be bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded.

In said formula (iv), R < ⁹ > is a C1-C20 monovalent organic group containing an electron withdrawing group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ^{5 to} R ⁸ include, for example, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or —CO—, —COO—, and —OCO. At least one group selected from the group consisting of —, —O—, —NR—, —CS—, —S—, —SO— and —SO ₂ — and a monovalent hydrocarbon group having 1 to 20 carbon atoms. And a combination of these and the like.

  Part or all of the hydrogen atoms of the monovalent hydrocarbon group may be substituted with a substituent. As said substituent, a fluorine atom, a hydroxy group, a carboxy group, a cyano group etc. are mentioned, for example.

R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Examples of the monovalent organic group for R include the same groups as those exemplified above for R ^{5 to} R ⁸ .

  Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include an alkyl group having 1 to 20 carbon atoms and a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

  Examples of the alkyl group having 1 to 20 carbon atoms include linear alkyl groups such as methyl group, ethyl group, n-propyl group, and n-butyl group; i-propyl group, i-butyl group, sec- Examples thereof include branched alkyl groups such as a butyl group and a t-butyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, methylcyclohexyl group, and ethyl. Monocyclic saturated hydrocarbon group such as cyclohexyl group; cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group, cyclodecenyl group, cyclopentadienyl group, cyclohexadienyl group, cyclooctadienyl group, cyclo Monocyclic unsaturated hydrocarbon group such as decadiene; bicyclo [2.2.1] heptyl group, bicyclo [2.2.2] octyl group, tricyclo [5.2.1.0 ^2,6 ] decyl group , Tricyclo [3.3.1.1 ^3,7 ] decyl group, tetracyclo [6.2. 1.1 ^{3, 6} . And a polycyclic saturated hydrocarbon group such as 0 ^2,7 ] dodecyl group. The “alicyclic hydrocarbon group” does not need to be composed only of the structure of the alicyclic hydrocarbon, and a part thereof may include a chain structure.

As the ^{R 5} and ^{R 6,} a monovalent hydrocarbon group having 1 to 20 carbon atoms, a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms preferably.

R ⁷ and R ⁸ are preferably a group in which —CO— and a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms are combined.

Examples of the monovalent organic group having 1 to 20 carbon atoms including the electron withdrawing group represented by R ⁹ include, for example, 1 to 1 carbon atoms in which at least some of the hydrogen atoms are substituted with electron withdrawing groups. And 20 hydrocarbon groups. Examples of the electron withdrawing group include a halogen atom such as a fluorine atom and a chlorine atom, a nitro group, and a cyano group, and a fluorine atom, a nitro group, and a cyano group are preferable. The hydrocarbon groups of 1 to 20 carbon atoms, and monovalent hydrocarbon groups of ^R 5 carbon atoms exemplified as the monovalent organic group having 1 to 20 carbon atoms represented by to R ⁸ 1-20 The same group etc. are mentioned.

  Preferred examples of the groups represented by the above formulas (ii) to (iv) include the following formulas (ii-1) to (ii-4) as the above formula (ii) and the following formula (iii) as the following formula (iii): As the formula (iii-1), the above formula (iv) includes the following formulas (iv-1) to (iv-4).

  Among these, from the viewpoint of excellent crosslinking reactivity of the crosslinking agent (B) and improving the heat resistance and bending resistance of the formed resist underlayer film, the group represented by the formula (ii), the formula (iv) A group represented by formula (iv) is more preferred, a group represented by formula (iv-3), a group represented by formula (iv-4) is more preferred, and a group represented by formula (iv) -3) is particularly preferred.

  As the aromatic hydrocarbon group represented by Ar in the above formula (i), from a compound containing a benzene aromatic ring such as a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, a fluorenylidene biphenyl ring, this benzene type Examples include groups other than hydrogen atoms in the aromatic ring or groups other than the number of hydrogen atoms bonded to the group. As said aromatic hydrocarbon group, a C6-C30 aromatic hydrocarbon group is preferable.

  Examples of the heteroaromatic group represented by Ar in the above formula (i) include a furan ring, a pyrrole ring, a thiophene ring, a phosphole ring, a pyrazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, and a pyrimidine. Examples thereof include groups obtained by removing hydrogen atoms corresponding to the number of bonds to atoms or groups other than hydrogen atoms of the heteroaromatic rings from compounds containing heteroaromatic rings such as rings, pyridazine rings, and triazine rings. The heteroaromatic group is preferably a C3-C30 heteroaromatic group.

  As n of said Formula (i), the integer of 1-7 is preferable, the integer of 1-5 is more preferable, and the integer of 1-3 is more preferable.

  Examples of the crosslinking agent (B) having the above-described structure include a compound represented by the following formula (b1), a compound represented by the following formula (b2), and the like.

In the above formula (b1),
X and Q are synonymous with the above formula (i).
Ar ¹ is a (n ₁ + n ₂ +1) -valent aromatic hydrocarbon group or a (n ₁ + n ₂ +1) -valent heteroaromatic group.
Ar ² is an (n ₃ + n ₄ +1) -valent aromatic hydrocarbon group or a (n ₃ + n ₄ +1) -valent heteroaromatic group.
R ² is each independently a hydroxy group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.
R ³ represents a single bond, a divalent hydrocarbon group having 1 to 30 carbon atoms, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO. _2- , -NR- or a divalent group in which these groups are combined. R is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
R ⁴ is a single bond, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ —, —NR—, or C 1-30. It is a (n ₅ +1) valent hydrocarbon group or a (n ₅ +1) valent group obtained by combining these groups. R is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
n ₁ is an integer of 1 to 7. n ₂ is an integer of 0 to 6. However, n ₁ + n ₂ is 7 or less.
n ₃ is an integer of 1 to 7. n ₄ is an integer of 0 to 6. However, n ₃ + n ₄ is 7 or less.
n ₅ is an integer of 1 to 5.
^{Ar 2, R 2, R 3} , if X and Q are a plurality each of a plurality of ^{Ar 2, R 2, R 3} , X and Q may each be the same or different.

In the above formula (b2),
X and Q are synonymous with the above formula (i).
Ar ³ is an (n ₆ + n ₇ ) -valent aromatic hydrocarbon group or a (n ₆ + n ₇ ) -valent heteroaromatic group.
R ² is a hydroxy group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.
n ₆ represents an integer of 1 to 8. n ₇ is an integer of 0 to 7. However, n ₆ + n ₇ is 8 or less.
R ^2, if ^X and Q are a plurality each of the plurality of R ^2, X and Q may be the same as or different from each other.

The monovalent hydrocarbon group having 1 to 30 carbon atoms of R ² in the above formula (b1) may have a substituent. Examples of the substituent include a halogen atom and a hydroxy group. As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.

As a C1-C20 bivalent hydrocarbon group represented by R < ³ > of said formula (b1), a C1-C20 bivalent linear or branched hydrocarbon group, carbon number 3 -20 divalent alicyclic hydrocarbon group, C6-C20 divalent aromatic hydrocarbon group, or a group obtained by combining these groups.

  As said C1-C20 bivalent linear or branched hydrocarbon group, a C2-C8 linear or branched alkylene group is preferable, an ethylene group, a propylene group, a butylene group, A hexylene group and an octylene group are more preferable.

  The divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms is preferably an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and the monocyclic alicyclic hydrocarbon group is a cyclopentylene group. The cyclohexylene group and the polycyclic alicyclic hydrocarbon group are preferably a norbornanediyl group and an adamantanediyl group.

  The divalent aromatic hydrocarbon group having 6 to 20 carbon atoms is preferably an aromatic hydrocarbon group having 6 to 15 carbon atoms, more preferably a phenylene group, a tolylene group, or a naphthylene group.

The (n ₅ +1) valent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁴ in the above formula (b1) is a linear or branched chain having 1 to 20 carbon atoms (n ₅ +1) valent. A hydrocarbon group having 3 to 20 carbon atoms, an (n ₅ +1) valent alicyclic hydrocarbon group having 6 to 20 carbon atoms, an (n ₅ +1) valent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a combination thereof. Groups and the like.

Examples of the (n ₅ +1) -valent linear or branched hydrocarbon group having 1 to 30 carbon atoms include linear or branched carbonic groups such as methane, ethane, propane, butane, ethylene, and acetylene. And groups obtained by removing (n ₅ +1) hydrogen atoms from hydrogen.

The (n 5 ₊₁₎ -valent alicyclic hydrocarbon groups of 3 to 30 carbon atoms, for example, cyclopropane, cyclobutane, cyclopentane, alicyclic hydrocarbons such as cyclohexane (n 5 ₊₁₎ number of hydrogen Examples include groups other than atoms.

Examples of the (n ₅ +1) -valent aromatic hydrocarbon group having 6 to 30 carbon atoms include (n ₅ +1) hydrogen atoms from aromatic hydrocarbons such as benzene, naphthalene, anthracene, pyrene and coronene. Excluded groups and the like.

It is composed of —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ — and —NR— represented by R ³ in the above formula (b1). As a divalent group combining at least one selected from the group and a C1-C30 divalent hydrocarbon group, from the structures represented by the following formulas (R-1) to (R-4): Examples include a group in which two hydrogen atoms are removed.

It consists of —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ — and —NR— represented by R ⁴ in the formula (b1). the at least one and 1-30 carbon _(n 5 +1) valent hydrocarbon combining the group _(n 5 +1) -valent group selected from the group of the following formula (R-1) ~ (R- And a group obtained by removing (n ₅ +1) hydrogen atoms from the structure represented by 4).

In the above formulas (R-1) to (R-4),
Ar ⁴⁰ is an n ₁₁ valent aromatic hydrocarbon group having 6 to 20 carbon atoms. Ar ⁴¹ is each independently an (n ₁₂ +1) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms. Ar ⁴² is an (n ₁₃ +2) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms. Ar ⁴³ is an (n ₁₅ + n ₁₆ ) -valent aromatic hydrocarbon group having 6 to 20 carbon atoms.
R ⁴⁰ each independently represents a monovalent chain hydrocarbon group having 1 to 12 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, or these groups and —CO—, — COO -, - OCO -, - O -, - CS -, - S -, - SO -, - SO 2 - and a monovalent group formed by combining at least one group selected from the group consisting of -NR- It is. R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.
R ⁴¹ each independently represents a single bond, —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ —, —NR—, carbon, A divalent chain hydrocarbon group having 1 to 12 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, or a divalent group obtained by combining these groups. R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.
R ⁴² and R ⁴³ are each independently a monovalent chain hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms. R ⁴² and R ⁴³ may be bonded to each other to form a ring structure together with Y to which they are bonded.
n ₁₁ is an integer of from 1 to 6. n ₁₂ is an integer from 0 to 5. n ₁₃ is an integer of 0-4. n ₁₄ is an integer from 0 to 5. n ₁₅ is an integer of from 1 to 6. n ₁₆ is an integer from 0 to 5. Y is —CO—, —COO—, —OCO—, —O—, —CS—, —S—, —SO—, —SO ₂ — or —NR—. R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ^{Ar 41,} Ar 42, ^{R 40} and when ^{R 41} is plural, respectively, a plurality of ^{Ar 41, Ar 42, R 40} and ^{R 41} may respectively be the same or different.

Examples of the monovalent chain hydrocarbon group having 1 to 12 carbon atoms represented by R ⁴⁰ , R ⁴² and R ⁴³ in the above formulas (R-1) to (R-4) include a methyl group and an ethyl group. N-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms represented by R ⁴⁰ , R ⁴² and R ⁴³ in the above formulas (R-1) to (R-4) include, for example, a cyclopropyl group, Examples include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.

Examples of the divalent chain hydrocarbon group having 1 to 12 carbon atoms represented by R ⁴¹ in the above formulas (R-2) and (R-3) include a methylene group, an ethylene group, and 1,2-propylene. Group, 1,3-propylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group and the like.

Examples of the divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms represented by R ⁴¹ in the formulas (R-2) and (R-3) include a cyclopentylene group and a cyclohexylene group. A monocyclic alicyclic hydrocarbon group; a polycyclic alicyclic hydrocarbon group such as a norbornanediyl group and an adamantanediyl group;

R ^{40 to} R ⁴³ in the above formulas (R-1) to (R-4) may have a substituent. Examples of the substituent include a halogen atom and a hydroxy group.

  As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.

N ₁ and n _{3 in} the formula (b1) are integers of 1 to 7, an integer of 1 to 5 is preferable, and an integer of 1 to 3 is more preferable.

N ₂ and n _{4 in} the formula (b1) are integers of 0 to 7, an integer of 0 to 5 is preferable, and an integer of 0 to 3 is more preferable.

N _{5 in the} formula (b1) is an integer of 1 to 5, and an integer of 1 to 3 is preferable.

Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by R ² in the above formula (b2) and the substituent that this group may have include R ² in the above formula (b1). And the like.

_{N 6} in the above formula (b2) is an integer of 1-8, preferably an integer of 1 to 5, an integer of 1 to 3 is more preferable.

_{N 7} of the formula (b2) is an integer of 0-7, preferably an integer of 0 to 5, more preferably an integer of 0 to 3.

  Here, as a specific crosslinking agent (B), the compound etc. which are represented by following formula (B-1)-(B-4) are mentioned, for example.

  These crosslinking agents (B) may be used alone or in combination of two or more.

  As content of a crosslinking agent (B), it is 0.1 mass part or more and 100 mass parts or less normally with respect to 100 mass parts of resin (A) of the said resin composition for resist lower layer film formation, Preferably it is 0. 5 parts by mass or more and 50 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less, and further preferably 5 parts by mass or more and 15 parts by mass or less.

[Other cross-linking agents]
In the resist underlayer film forming resin composition, a crosslinking agent other than the above-described crosslinking agent (B) may be blended.

  Examples of other crosslinking agents include polynuclear phenols and various commercially available curing agents. As such other crosslinking agents, for example, those described in paragraphs [0085] to [0086] in JP-A No. 2004-168748 can be used.

  These other crosslinking agents may be used singly or in combination of two or more, and polynuclear phenols and a curing agent may be used in combination.

  The content of the other crosslinking agent is usually 0.1 parts by mass or more and 100 parts by mass or less, preferably 0.1 parts by mass with respect to 100 parts by mass of the resin (A) of the resin composition for forming a resist underlayer film. 5 parts by mass or more and 50 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less.

[Solvent (C)]
The resist underlayer film forming resin composition contains the above-described resin (A) and cross-linking agent (B), and this composition usually contains a solvent (hereinafter referred to as “solvent (C) ) ")).

  The solvent (C) is not particularly limited as long as it can dissolve the resin (A). For example, those described in paragraphs [0070] to [0073] in JP-A No. 2004-168748 are used. Can do.

  Among these solvents (C), propylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone, γ -Butyrolactone is preferred.

  In addition, a solvent (C) may be used individually by 1 type, and may be used in combination of 2 or more type.

  As content of a solvent (C), solid content concentration of the composition obtained is 1 mass%-80 mass% normally, Preferably it is 3 mass%-40 mass%, More preferably, 5 mass%-30 mass%, Especially preferably, it is the range used as 7 mass%-20 mass%.

  In the resist underlayer film forming resin composition, an acid generator (D), an accelerator (E), and an additive (F) are blended as necessary unless the desired effect in the present invention is impaired. be able to. Among these, it is preferable that the accelerator (E) is blended.

[Acid generator (D)]
The acid generator (D) is a component that generates an acid upon exposure or heating. By including the acid generator (D), the resist underlayer film forming resin composition can effectively cause a crosslinking reaction between the molecular chains of the resin at a relatively low temperature including normal temperature.

  Examples of the acid generator that generates an acid upon exposure (hereinafter referred to as “photoacid generator”) include those described in paragraphs [0077] to [0081] of JP-A No. 2004-168748. .

  Among these photoacid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylpheny ) Iodonium naphthalene sulfonate is preferred.

  In addition, these photo-acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the acid generator that generates an acid by heating (hereinafter referred to as “thermal acid generator”) include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, and 2-nitrobenzyl tosylate. And alkyl sulfonates.

  In addition, these thermal acid generators may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, you may use together a photo-acid generator and a thermal acid generator as an acid generator (D).

  The content of the acid generator (D) is usually 5,000 parts by mass or less, preferably 0.1 parts by mass to 100 parts by mass of the resin (A) of the resin composition for forming a resist underlayer film. 1,000 parts by mass, more preferably 0.1 parts by mass to 100 parts by mass, and particularly preferably 1 part by mass to 10 parts by mass.

[Accelerator (E)]
The accelerator (E) is a one-electron oxidizer or the like for sufficiently causing a dehydrogenation reaction necessary for oxidative crosslinking. One-electron oxidant means an oxidant that itself undergoes one-electron transfer. For example, in the case of cerium (IV) ammonium nitrate, cerium ion (IV) obtains one electron and changes to cerium ion (III). Alternatively, a radical oxidizing agent such as halogen obtains one electron and converts it into an anion. In this way, the phenomenon of oxidizing the oxide by taking one electron from the oxide (substrate, catalyst, etc.) is called one-electron oxidation, and the component that receives one electron at this time is called a one-electron oxidant.

  Typical examples of the one-electron oxidant include (a) metal compound, (b) peroxide, (c) diazo compound, (d) halogen or halogen acid.

Examples of the metal compound (a) include metal compounds containing cerium, lead, silver, manganese, osmium, ruthenium, vanadium, thallium, copper, iron, bismuth, and nickel. Specifically, (a1) cerium salts (such as cerium (IV) ammonium nitrate (CAN; ammonium hexanitratocerium (IV)), cerium (IV) acetate, cerium (IV) nitrate, cerium (IV) sulfate ( For example, tetravalent cerium salt), (a2) lead tetraacetate, lead oxide such as lead (IV) oxide (eg, tetravalent lead compound), (a3) silver (I) oxide, silver (II) oxide, Silver carbonate (Fetizon reagent), silver compounds such as silver nitrate, (a4) manganese compounds such as permanganate, activated manganese dioxide, manganese (III) salts, (a5) osmium compounds such as osmium tetroxide, (a6) Ruthenium compounds such as ruthenium oxide, (a7) Vanadium compounds such as VOCl ₃ , VOF ₃ , V ₂ O ₅ , NH ₄ VO ₃ , NaVO ₃ , (a8) Tariu acetate (III), thallium compounds such as thallium (III) trifluoroacetate, thallium (III) nitrate, (a9) copper (II) acetate, copper (II) trifluoromethanesulfonate, copper (II) trifluoroborate, copper chloride (II), copper compounds such as copper (I) acetate, (a10) iron compounds such as iron (III) chloride and potassium hexacyanoferrate (III), (a11) bismuth compounds such as sodium bismuth, (a12) Examples thereof include nickel compounds such as nickel oxide.

  Examples of the (b) peroxide include peracids such as peracetic acid and m-chloroperbenzoic acid; hydroxyperoxides such as hydrogen peroxide and alkylhydroxyperoxide such as t-butyl hydroperoxide; diacyl peroxide; , Peracid ester, peracid ketal, peroxydicarbonate, dialkyl peroxide, peracid ketone and the like.

  Examples of the (c) diazo compound include 2,2'-azobisisobutyronitrile.

  Examples of the above (d) halogen or halogen acid include halogen selected from chlorine, bromine and iodine, perhalogen acid, halogen acid, halogen acid, hypohalous acid and salts thereof. Examples of the halogen in the halogen acid include chlorine, bromine, and iodine. Or as a specific compound used as a halogen acid or its salt, sodium perchlorate, sodium bromate, etc. are mentioned.

  Among these one-electron oxidants, (b) peroxides and (c) diazo compounds are preferred, and in particular, m-chloroperbenzoic acid, t-butyl hydroperoxide, 2,2′-azobisisobutyronitrile. Is preferred. When these are used, there is no possibility that metal residues or the like adhere to the substrate, which is preferable.

  In addition, a promoter (E) may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the accelerator (E) is usually 1,000 parts by mass or less, preferably 0.01 parts by mass to 500 parts per 100 parts by mass of the resin (A) of the resin composition for forming a resist underlayer film. Part by mass, more preferably 0.1 part by mass to 100 parts by mass.

[Additive (F)]
As said additive (F), binder resin, a radiation absorber, surfactant, etc. are mentioned.

  As these additives (F), for example, those described in paragraphs [0088] to [0093] in JP-A No. 2004-168748 can be used.

  As the binder resin, various thermoplastic resins and thermosetting resins (excluding the above-described resin (A)) can be used. A thermoplastic resin is a component which has the effect | action which provides the fluidity | liquidity, mechanical characteristic, etc. of the added thermoplastic resin to a resist underlayer film. The thermosetting resin is a component that is cured by heating and becomes insoluble in a solvent, and has a function of preventing intermixing between the resulting resist underlayer film and the resist film formed thereon. It can be preferably used as a resin. Among these, thermosetting resins are preferable, and urea resins, melamine resins, and aromatic hydrocarbon resins are more preferable.

  In addition, these binder resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  As content of the said binder resin, it is 20 mass parts or less normally with respect to 100 mass parts of resin (A) in the said resin composition for resist lower layer film formation, Preferably it is 10 mass parts or less.

  As content of the said radiation absorber, it is 100 mass parts or less normally with respect to 100 mass parts of resin (A) of the said resin composition for resist underlayer film formation, Preferably it is 50 mass parts or less.

  The surfactant is a component having an effect of improving coatability, striation, wettability, developability and the like.

  These surfactants may be used individually by 1 type, and may be used in combination of 2 or more type.

  As content of the said surfactant, it is 15 mass parts or less normally with respect to 100 mass parts of resin (A) of the said resin composition for resist underlayer film formation, Preferably it is 10 mass parts or less.

  In addition to the above-described additives, other additives such as a storage stabilizer, an antifoaming agent, and an adhesion aid can be blended with the resist underlayer film forming resin composition.

<Resist underlayer film>
The resist underlayer film of the present invention is formed from the resist underlayer film forming resin composition. In addition, about this resist underlayer film forming resin composition, the description of the above-mentioned resist underlayer film forming resin composition of this invention is applicable as it is.

  This resist underlayer film is formed by forming a resist underlayer film on the upper surface side of the substrate, forming a resist pattern on the upper surface side of the resist underlayer film, and then transferring the resist pattern to the resist underlayer film to form an underlayer film pattern. The lower layer film pattern can be suitably used in a multilayer resist process for transferring to a substrate using an etching mask.

  The hydrogen content of the resist underlayer film is usually 0 to 50 atom%, preferably 0 to 35 atom%. The hydrogen content in the resist underlayer film was determined by measuring the mass-converted value (% by mass) of each element of the resist underlayer film using a carbon / hydrogen / nitrogen simultaneous determination apparatus (“JM10” from J Science Laboratories). From this mass conversion value, the number of atoms of each element is calculated by [mass conversion value of each element (mass%) / atomic weight of each element (g / mol)], and from the value of the number of atoms of each element, [ The number of hydrogen atoms in the resist underlayer film / the total number of atoms in the resist underlayer film].

  A method for forming such a resist underlayer film is not particularly limited, and examples thereof include a method for forming a resist underlayer film of the present invention described later.

<Method for forming resist underlayer film>
The method for forming a resist underlayer film of the present invention includes a step of forming a coating film on the upper surface side of a substrate with the resin composition for forming a resist underlayer film, and a step of heating the coating film and the substrate. For the resist underlayer film forming resin composition, the description of the resist underlayer film forming resin composition of the present invention can be applied as it is.

  As the substrate, for example, a silicon wafer, a wafer coated with aluminum, or the like can be used.

  Moreover, the application | coating method of the resin composition for resist underlayer film formation to a board | substrate is not specifically limited, For example, it can implement by appropriate methods, such as spin coating, cast coating, and roll coating.

  The coating film is usually heated in the atmosphere (oxygen concentration of about 20% by volume).

  The heating temperature at this time is usually 300 ° C to 500 ° C, preferably 350 ° C to 450 ° C. When this heating temperature is less than 300 ° C., the oxidative crosslinking does not proceed sufficiently, and there is a possibility that the characteristics necessary for the resist underlayer film may not be exhibited.

  The heating time at this time is usually 30 seconds to 1,200 seconds, and preferably 60 seconds to 600 seconds.

  The oxygen concentration when the coating is cured is preferably 5% by volume or more. When the oxygen concentration at the time of coating film formation is low, the oxidation cross-linking of the resist underlayer film does not proceed sufficiently, and there is a possibility that the characteristics necessary for the resist underlayer film cannot be expressed.

  Moreover, before heating a coating film at the temperature of 300 to 500 degreeC, you may preheat at the temperature of 60 to 250 degreeC.

  The heating time in the preheating is not particularly limited, but is preferably 10 seconds to 300 seconds, and more preferably 30 seconds to 180 seconds.

  By performing this preheating, the dehydrogenation reaction can be efficiently advanced by vaporizing the solvent in advance and keeping the film dense.

  In the method for forming the resist underlayer film, the coating film is usually cured by heating the coating film to form a resist underlayer film. A predetermined photocuring agent ( By containing a photocrosslinking agent), an exposure step for the heated coating film can be provided and photocured to form a resist underlayer film. The radiation exposed at this time is visible light, ultraviolet light, far ultraviolet light, X-rays, electron beam, γ-ray, molecular beam, depending on the type of acid generator blended in the resin composition for forming the resist underlayer film. The ion beam is appropriately selected.

<Pattern formation method>
The pattern forming method of the present invention comprises a step of forming a resist underlayer film on the upper surface side of the substrate with the resin composition for forming a resist underlayer film (hereinafter also referred to as “resist underlayer film forming step”), and the resist underlayer film. A step of forming a resist pattern on the upper surface side of the film (hereinafter also referred to as “resist pattern forming step”), and a step of sequentially etching the resist underlayer film and the substrate using the resist pattern as a mask (hereinafter referred to as “etching step”). ").

[Resist underlayer film forming step]
In the resist underlayer film forming step, a resist underlayer film is formed on the upper surface side of the substrate. The above description can be applied as it is for the method of forming the resist underlayer film.

  The film thickness of the resist underlayer film formed in this step is usually 0.1 μm to 5 μm.

  In addition, this pattern forming method may further include a step of forming an intermediate layer (intermediate coating) on the resist lower layer film as necessary after the resist lower layer film forming step.

  This intermediate layer is a layer provided with these functions in order to further supplement the functions of the resist underlayer film and / or resist film in forming the resist pattern, or to obtain functions that they do not have. . For example, when the antireflection film is formed as an intermediate layer, the antireflection function of the resist underlayer film can be further supplemented.

  This intermediate layer can be formed of an organic compound or an inorganic oxide. Examples of organic compounds include commercially available materials such as “DUV-42”, “DUV-44”, “ARC-28”, and “ARC-29” manufactured by Brewer Science, and “AR-3” manufactured by Rohm and Haas. Commercial materials such as “AR-19” can be used. Examples of the inorganic oxide include commercially available materials such as “NFC SOG01”, “NFC SOG04”, “NFC SOG080” manufactured by JSR, and polysiloxane, titanium oxide, alumina oxide, tungsten oxide, etc. formed by the CVD method. Can be used.

  Although the method for forming the intermediate layer is not particularly limited, for example, a coating method, a CVD method, or the like can be used. Among these, a coating method is preferable. When the coating method is used, the intermediate layer can be formed continuously after forming the resist underlayer film.

  The film thickness of the intermediate layer is not particularly limited and is appropriately selected depending on the function required for the intermediate layer, but is preferably 10 nm to 3,000 nm, and more preferably 20 nm to 300 nm.

[Resist pattern formation process]
In the resist pattern forming step, a resist pattern is formed on the upper surface side of the resist underlayer film. Examples of a method for forming this resist pattern include a method using photolithography.

  A method of forming a resist pattern using photolithography includes a step of forming a resist film with a resist composition on the upper surface side of the resist underlayer film (hereinafter also referred to as “resist film forming step”), and exposing the resist film. And a step of developing the exposed resist film (hereinafter also referred to as “developing step”).

(Resist film formation process)
In the resist film forming step, a resist film is formed on the upper surface side of the resist underlayer film using the resist composition. Specifically, after applying the resist composition so that the resulting resist film has a predetermined thickness, the solvent in the coating film is usually volatilized by pre-baking to form a resist film.

  Examples of the resist composition include a positive or negative chemically amplified resist composition containing a photoacid generator, a positive resist composition comprising an alkali-soluble resin and a quinonediazide-based photosensitizer, and an alkali-soluble resin and a crosslinking agent. And negative resist compositions composed of an agent.

  The resist composition used when the resist film is formed on the resist underlayer film has a solid concentration of usually about 1% by mass to 50% by mass, and is generally a filter having a pore size of about 0.2 μm, for example. Filtration is performed for forming a resist film. In this step, a commercially available resist composition can be used as it is.

  The method for applying the resist composition is not particularly limited, and for example, the resist composition can be applied by a spin coating method or the like.

  The pre-baking temperature is appropriately adjusted according to the type of resist composition used and the like, but is usually about 30 ° C to 200 ° C, preferably 50 ° C to 150 ° C.

(Exposure process)
In the exposure step, radiation is irradiated onto a predetermined region of the obtained resist film, and exposure is selectively performed.

The radiation used for the exposure is appropriate from visible light, ultraviolet light, far ultraviolet light, X-rays, electron beams, γ rays, molecular beams, ion beams, etc., depending on the type of photoacid generator used in the resist composition. However, far ultraviolet rays are preferable, 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) ) And extreme ultraviolet rays (wavelength 13 nm, etc.) are preferable.

  In order to improve resolution, pattern profile, developability, etc., post-baking can be performed after the exposure. The post-baking temperature is appropriately adjusted according to the type of resist composition used, but is usually about 50 ° C to 200 ° C, preferably 70 ° C to 150 ° C.

(Development process)
In the development step, the resist film exposed in the exposure step is developed with a developer. Thereby, a resist pattern is formed.

  The developer used in this step is appropriately selected according to the type of resist composition used. Specifically, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanol Amine, 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 the like.

  An appropriate amount of a water-soluble organic solvent, for example, an alcohol such as methanol or ethanol, or a surfactant can be added to these alkaline aqueous solutions.

  As the developer, a liquid containing an organic solvent can also be used. As such an organic solvent, the solvent similar to what was illustrated as said solvent (C), etc. are mentioned.

  In addition, after developing with the developer, the resist pattern is formed by washing and drying.

  Examples of a method for forming a resist pattern in the resist pattern forming step include a method using nanoimprint lithography, a method using a self-organizing composition, and the like in addition to the method using photolithography.

[Etching process]
In the etching step, the resist underlayer film and the substrate are sequentially etched using the obtained resist pattern as a mask. Examples of the etching include dry etching using gas plasma such as oxygen plasma, wet etching using an acid solution, and the like. Among these, dry etching is preferable in that a finer substrate pattern can be obtained. By performing this etching step, a predetermined substrate pattern is obtained.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Here, “part” and “%” are based on mass unless otherwise specified.

  In addition, the measurement of the weight average molecular weight (Mw) in a present Example uses the Tosoh "GPC column" (G2000HXL: 2 pieces, G3000HXL: 1 piece), flow volume: 1.0 ml / min, elution solvent: tetrahydrofuran, column Temperature: Measured by gel permeation chromatograph (detector: differential refractometer) using monodispersed polystyrene as a standard under analysis conditions of 40 ° C.

<Synthesis of Resin (A)>
[Synthesis Example 1] (Synthesis of Resin (A-1))
A reactor equipped with a condenser, a thermometer, and a stirrer was charged with 100 parts of 2,7-dihydroxynaphthalene, 100 parts of propylene glycol monomethyl ether acetate and 50 parts of paraformaldehyde, added with 2 parts of oxalic acid, and while dehydrating, 120 By raising the temperature to ° C. and reacting for 5 hours, a resin (A-1) composed of a repeating unit represented by the following formula (A-1) was obtained. Mw of the obtained resin (A-1) was 2,000.

[Synthesis Example 2] (Synthesis of Resin (A-2))
A reactor equipped with a condenser, thermometer, and stirrer was charged with 100 parts of fluorene bisphenol, 100 parts of propylene glycol monomethyl ether acetate, and 50 parts of paraformaldehyde, added with 2 parts of oxalic acid, and heated to 120 ° C. while dehydrating. Then, by reacting for 5 hours, a resin (A-2) composed of a repeating unit represented by the following formula (A-2) was obtained. Mw of the obtained resin (A-2) was 4,000.

[Synthesis Example 3] (Synthesis of Resin (A-3))
A separable flask equipped with a thermometer was charged with 100 parts of acenaphthylene, 78 parts of toluene, 52 parts of dioxane and 3 parts of azobisisobutyronitrile under nitrogen and stirred at 70 ° C. for 5 hours. To the obtained resin having a molecular weight of 10,000, 5.2 parts of p-toluenesulfonic acid monohydrate and 40 parts of paraformaldehyde were added, the temperature was raised to 120 ° C., and the mixture was further stirred for 6 hours. Thereafter, the reaction solution was poured into a large amount of isopropanol, and the precipitated resin was filtered to obtain a resin (A-3) composed of a repeating unit represented by the following formula (A-3). Mw of the obtained resin (A-3) was 20,000.

<Preparation of Resin Underlayer Film Forming Resin Composition>
[Example 1]
As shown in Table 1, 10 parts of the above resin (A-1) as the resin (A), 1 part of the following compound (B-1) as the crosslinking agent (B), and the acid generator (D) (heat 0.5 part of diphenyliodonium trifluoromethanesulfonate (D-1) as an acid generator was dissolved in 90 parts of propylene glycol monomethyl ether acetate (C-1) as a solvent (C). This solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resin composition for forming a resist underlayer film of Example 1.

[Examples 2 to 6]
Except having used each component of the kind and content shown in Table 1, it carried out similarly to Example 1, and prepared each resin composition for resist underlayer film formation of Examples 2-6.

  In addition, resin (A-1)-(A-3) used by Examples 1-6 in Table 1 is resin obtained by the above-mentioned synthesis examples 1-3. Moreover, the crosslinking agents (B-1) to (B-4) in Table 1 are as follows and are synthesized by the following methods, respectively.

[Synthesis Example 4] (Synthesis of cross-linking agent (B-1))
60 parts of dichloromethane was added to a flask equipped with a thermometer, 15 parts of isophthaloyl chloride was dissolved, and the mixture was cooled to 0 ° C. in an ice bath. 8 parts 1,1,1,3,3,3-hexafluoro-2-propanol was added into the flask and a solution of 5 parts triethylamine in 12 parts dichloromethane was added dropwise with stirring. . After completion of dropping, the mixture was stirred at 0 ° C. for 2 hours. After confirming the disappearance of the raw material isophthaloyl chloride by thin layer chromatography, 100 parts of 1% by mass oxalic acid water was added to the reaction system. After removing the aqueous phase with a separatory funnel and repeating this operation twice, 100 parts of ion exchange water was added, and the operation of removing the aqueous phase with a separatory funnel was performed twice. The solvent was removed from the obtained organic phase by distillation under reduced pressure, and purification was performed by column chromatography using a developing solvent of ethyl acetate / n-hexane to obtain a crosslinking agent (B-1).

[Synthesis Example 5] (Synthesis of crosslinking agent (B-2))
13 parts of dichloromethane was added to a flask equipped with a thermometer, 11 parts of oxalyl chloride was dissolved, and the mixture was cooled to 0 ° C. in an ice bath. 6 parts of trimesic acid were dissolved in 13 parts of dichloromethane and added dropwise to the flask. After confirming the disappearance of trimesic acid by thin-layer chromatography, 27 parts of 1,1,1,3,3,3-hexafluoro-2-propanol was added to the flask, and 13 parts of 16 parts of triethylamine was stirred. Of dichloromethane in dichloromethane was added dropwise. After completion of dropping, the mixture was stirred at 0 ° C. for 2 hours. Thereafter, 100 parts of 1% by mass oxalic acid water was added to the reaction system. After removing the aqueous phase with a separatory funnel and repeating this operation twice, 100 parts of ion exchange water was added, and the operation of removing the aqueous phase with a separatory funnel was performed twice. The solvent was removed from the obtained organic phase by distillation under reduced pressure, and purification was performed by column chromatography using a developing solvent of ethyl acetate / n-hexane to obtain a crosslinking agent (B-2).

[Synthesis Example 6] (Synthesis of cross-linking agent (B-3))
16 parts of dichloromethane was added to a flask equipped with a thermometer, 9 parts of oxalyl chloride was dissolved, and the mixture was cooled to 0 ° C. in an ice bath. 7 parts 2,6-naphthalenedicarboxylic acid was dissolved in 16 parts dichloromethane and added dropwise to the flask. After confirming disappearance of 2,6-naphthalenedicarboxylic acid by thin layer chromatography, 22 parts of 1,1,1,3,3,3-hexafluoro-2-propanol was added to the flask, and the mixture was stirred under 13 A solution of parts of triethylamine in 16 parts of dichloromethane was added dropwise. After completion of dropping, the mixture was stirred at 0 ° C. for 2 hours. Thereafter, 100 parts of 1% by mass oxalic acid water was added to the reaction system. After removing the aqueous phase with a separatory funnel and repeating this operation two more times, 100 parts of ion-exchanged water was added, and the operation of removing the aqueous phase with a separatory funnel was performed twice. The solvent was removed from the obtained organic phase by distillation under reduced pressure, and purification was performed by column chromatography using a developing solvent of ethyl acetate / n-hexane to obtain a crosslinking agent (B-3).

[Synthesis Example 7] (Synthesis of crosslinking agent (B-4))
27 parts of THF was added to a flask equipped with a thermometer, 12 parts of 2,6-naphthalenedicarboxylic acid was dissolved, and the mixture was cooled to 0 ° C. in an ice bath. Under a nitrogen atmosphere, 15 parts of oxalyl chloride was slowly added dropwise with stirring. After stirring at 0 ° C. for 2 hours, low-boiling components were removed with an evaporator. The residue was dissolved in 27 parts THF and cooled to 0 ° C. 8 parts of acetoxime was added to this THF solution, and 12 parts of triethylamine was further added. After completion of the dropwise addition, the reaction is carried out for 2 hours, 100 parts of 0.5N HCl is added, the aqueous phase is removed with a separatory funnel, this operation is repeated twice more, and then 100 parts of ion-exchanged water is added. The operation of removing the aqueous phase with a liquid funnel was performed twice. The solvent was removed from the obtained organic phase by distillation under reduced pressure, and purification was performed by column chromatography using a developing solvent of ethyl acetate / n-hexane to obtain a crosslinking agent (B-4).

[Comparative Example 1]
As shown in Table 1, 10 parts of the resin (A-1) described above as the resin (A), 1 part of the following compound (b-1) as the crosslinking agent, and an acid generator (D) (thermal acid generation) 0.5 part of diphenyliodonium trifluoromethanesulfonate (D-1) as an agent was dissolved in 90 parts of propylene glycol monomethyl acetate (C-1) as a solvent (C). This solution was filtered through a membrane filter having a pore size of 0.1 μm to prepare a resin composition for forming a resist underlayer film of Comparative Example 1.

<Evaluation>
The following evaluation was performed about each resin underlayer film forming resin composition of Examples 1-6 and Comparative Example 1. The results are shown in Table 2.

[Resist shape]
A silicon oxide film of 0.3 μm was deposited on a 12-inch diameter silicon wafer by CVD. Next, each resist underlayer film forming resin composition was spin-coated, heated at 180 ° C. for 60 seconds in a hot plate having an oxygen concentration of 20% by volume, and subsequently heated at 350 ° C. for 120 seconds to obtain a film thickness of 0. A resist underlayer film of 25 μm was formed. Next, an intermediate layer forming composition solution for a three-layer resist process (NFC SOG508, manufactured by JSR) is spin-coated on this resist underlayer film, and then heated at 200 ° C. for 60 seconds, and subsequently heated at 300 ° C. for 60 seconds. An intermediate layer having a thickness of 0.04 μm was formed. Next, a resist composition was spin-coated on this intermediate layer, and pre-baked at 100 ° C. for 60 seconds to form a resist film having a thickness of 0.1 μm. A commercially available resist composition (ARX3038JN, manufactured by JSR) was used.

  Next, using an ArF immersion exposure apparatus (lens numerical aperture 1.30, exposure wavelength 193 nm, manufactured by NIKON), exposure was performed for an optimal exposure time through a mask. Next, after post-baking at 100 ° C. for 60 seconds, the resist film was developed using a 2.38 mass% tetramethylammonium hydroxide aqueous solution. Thereafter, it was washed with water and dried to form a positive resist pattern.

  Then, the resist film on which the positive resist pattern was formed was observed with a scanning electron microscope and evaluated according to the following criteria (referred to as “resist shape” in Table 2). The case where the observed pattern shape is a rectangle is good (denoted as “A” in Table 2), and the shape other than the rectangle (for example, T-top, scum, etc.) is defective (“B” in Table 2). ).

[Bending resistance]
A silicon oxide film of 0.3 μm was deposited on a 12-inch diameter silicon wafer by CVD. Next, each resist underlayer film forming resin composition was spin-coated, heated at 180 ° C. for 60 seconds in a hot plate having an oxygen concentration of 20% by volume, and subsequently heated at 350 ° C. for 120 seconds to obtain a film thickness of 0. A resist underlayer film of 25 μm was formed. Next, an intermediate layer forming composition solution for a three-layer resist process (NFC SOG508, manufactured by JSR) is spin-coated on this resist underlayer film, and then heated at 200 ° C. for 60 seconds, and subsequently heated at 300 ° C. for 60 seconds. An intermediate layer having a thickness of 0.04 μm was formed. Next, the above resist composition was spin-coated on this intermediate layer and pre-baked at 100 ° C. for 60 seconds to form a resist film having a thickness of 0.1 μm.

  Next, using an ArF immersion exposure apparatus (lens numerical aperture 1.30, exposure wavelength 193 nm, manufactured by NIKON), exposure was performed for an optimal exposure time through a mask. Next, after post-baking at 100 ° C. for 60 seconds, the resist film was developed using a 2.38 mass% tetramethylammonium hydroxide aqueous solution. Thereafter, it was washed with water and dried to form a positive resist pattern. Next, using the resist film on which this pattern is formed as a mask, the intermediate layer is dry-etched with carbon tetrafluoride gas using a reactive ion etching type etching apparatus (Telius SCCM, manufactured by Tokyo Electron), When the intermediate layer located under the opening of the resist film disappeared, the etching process was stopped and the resist pattern was transferred to the intermediate layer.

  Next, using the intermediate layer to which the resist pattern was transferred as a mask, dry etching treatment was performed with a mixed gas of oxygen and nitrogen using the etching apparatus, and the resist underlayer film located below the intermediate layer opening was lost. By the way, the etching process was stopped and the pattern of the intermediate layer was transferred to the resist underlayer film. Next, using the resist underlayer film to which the intermediate layer pattern has been transferred as a mask, dry etching is performed with a mixed gas of carbon tetrafluoride and argon using the etching apparatus, and the resist underlayer film is positioned below the opening of the resist underlayer film. The etching process was stopped when the silicon oxide film to be removed was removed by 0.1 μm.

  Then, among the resist underlayer film patterns remaining on the substrate, the shape of a so-called line and space pattern in which linear patterns are arranged at equal intervals was observed with an SEM (scanning electron microscope). In this line and space pattern, the repetition interval is fixed at 84 nm and 100 linear patterns are arranged at equal intervals, and this is regarded as one set. There are 21 sets of pattern groups having different pattern widths on the same substrate, and the pattern widths are in increments of 1 nm from 50 nm to 30 nm. The pattern width referred to here is the width of one linear pattern arranged at equal intervals formed by the resist underlayer film. Of the same design pattern on the substrate, the pattern of each pattern width was observed with the SEM at five arbitrary locations, and the observation result was regarded as bending resistance. At this time, if all the patterns of the resist underlayer film are vertical, the bending resistance is “A”, the bending resistance is “B”, the bending resistance is “B”, and the bending resistance is “C” when two or more are bending.

[Etching resistance]
Each of the resist underlayer film forming resin compositions was spin-coated on a silicon wafer having a diameter of 8 inches, and then heated at 180 ° C. for 60 seconds in a hot plate having an oxygen concentration of 20% by volume. A resist underlayer film having a film thickness of 0.25 μm is formed by heating, and this resist underlayer film is CF ₄ / Ar / O ₂ (CF ₄ : 40 mL / min) using an etching apparatus “EXAM” (manufactured by Shinko Seiki). , Ar: 20 mL / min, O ₂ : 5 mL / min; pressure: 20 Pa; RF power: 200 W; treatment time: 40 seconds; temperature: 15 ° C.).

And the film thickness before and behind an etching process was measured, the etching rate was computed, and the etching tolerance was evaluated on the following reference | standard.
“A”: When the etching rate is 120 nm / min or less “B”: When the etching rate exceeds 120 nm / min

[Heat-resistant]
A resin film for forming each resist underlayer film was spin-coated on a silicon wafer having a diameter of 8 inches to form a coating film (resist underlayer film), and the film thickness of this coating film was measured using the above spectroscopic ellipsometer ( Let this measurement be X). Next, this resist underlayer film was heated at 350 ° C. for 120 seconds, and the film thickness of the resist underlayer film after heating was measured using the above spectroscopic ellipsometer (this measured value is set as Y). Then, the film thickness reduction rate ΔFT (%) (ΔFT (%) = 100 × (XY) / X) of the resist underlayer film before and after heating is calculated, and this calculated value is defined as heat resistance (%). . Compared with Comparative Example 1, the heat resistance improvement of 10% or more (which means that the heat resistance value is 90% or less) is “A (good)” and the heat resistance performance improvement is less than 10%. Was evaluated as “B (defect)”. In addition, the smaller the value of heat resistance (%), the fewer sublimates and film decomposition products generated during heating of the resist underlayer film, indicating better (high heat resistance). “-” In Table 2 indicates a criterion for evaluation.

  According to Table 2, according to each resist underlayer film forming resin composition of Examples 1 to 6, the pattern shape of the resist formed in the upper layer is good, and the bending resistance, etching resistance, and heat resistance are good. It was confirmed that a resist underlayer film can be formed.

  According to the resin composition for forming a resist underlayer film of the present invention, it is possible to form a resist underlayer film having a favorable resist pattern shape formed in an upper layer and having good bending resistance, etching resistance, and heat resistance. . Therefore, it can be used very suitably for fine processing in a lithography process. In particular, in the dry etching process, the resist pattern formed on the upper layer has a good pattern shape, and furthermore, has a precise pattern transfer performance and good etching selectivity. The resist pattern can be faithfully transferred with good reproducibility. In addition, since the lower layer film pattern is not bent when the substrate is etched, an improvement in yield can be expected in microfabrication in the lithography process, particularly in the manufacture of highly integrated circuit elements.

  And the pattern formation method of this invention using such a resin composition for resist underlayer film formation is very useful as a lithography process, especially the process for manufacturing a highly integrated circuit element.

Claims (7)

It contains a resin containing an aromatic ring, and a cross-linking agent,
A resin composition for forming a resist underlayer film , wherein the crosslinking agent is a compound represented by the following formula (b2) .

(In the formula (b2),
X is a carbonyl group or a sulfonyl group.
Q is a monovalent heteroaromatic group or —OR ¹ . R ¹ is a monovalent organic group having 1 to 30 carbon atoms represented by any of the following formulas (ii) to (iv).
Ar ³ is an (n ₆ + n ₇ ) -valent aromatic hydrocarbon group or a (n ₆ + n ₇ ) -valent heteroaromatic group.
R ² is a hydroxy group or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 30 carbon atoms.
n ₆ is an integer of 2 to 8. n ₇ is an integer from 0 to 6. However, n ₆ + n ₇ is 8 or less.
When R ² is plural, the plurality of R ² may be the same or different. A plurality of X and Q may be the same or different. )

(In formula (ii), R ⁵ and R ⁶ are each independently a monovalent organic group having 1 to 20 carbon atoms, provided that R ⁵ and R ⁶ are bonded to each other, and (A ring structure may be formed with the carbon atom to which it is bonded.)

(In Formula (iii), R ⁷ and R ⁸ are each independently a monovalent organic group having 1 to 20 carbon atoms, provided that R ⁷ and R ⁸ are bonded to each other, and (A ring structure may be formed together with the nitrogen atom bonded thereto.)

(In Formula (iv), R ⁹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms in which at least a part of hydrogen atoms is substituted with at least one of a halogen atom, a nitro group, and a cyano group. ) The resin composition for forming a resist underlayer film according to claim 1, wherein R ¹ of Q in the formula ( b2 ) is represented by the formula (iv).   2. The resin composition for forming a resist underlayer film according to claim 1, wherein the resin is at least one selected from the group consisting of a novolak resin, a resole resin, an acenaphthylene resin, a styrene resin, and a polyarylene resin.   The resin composition for forming a resist underlayer film according to claim 1, further comprising a solvent.   A resist underlayer film formed from the resin composition for forming a resist underlayer film according to claim 1. Forming a coating film on the upper surface side of the substrate with the resin composition for forming a resist underlayer film according to claim 1;
A method of forming a resist underlayer film comprising the step of heating the coating film and the substrate. Forming a resist underlayer film on the upper surface side of the substrate with the resin composition for forming a resist underlayer film according to claim 1;
Forming an intermediate layer on the resist underlayer film;
Forming a resist pattern on the upper surface side of the resist underlayer film;
Transferring the pattern of the resist pattern to the intermediate layer by etching using the resist pattern as a mask;
A step of transferring the pattern of the intermediate layer to the resist underlayer film by etching using the intermediate layer to which the pattern of the resist pattern is transferred as a mask;
Forming a pattern on the substrate by etching using the resist underlayer film to which the pattern of the intermediate layer is transferred as a mask.