JP5077026B2 - Composition for forming resist underlayer film and method of forming dual damascene structure using the same - Google Patents

Description

  The present invention relates to a resin composition for a resist underlayer film suitable for microfabrication in a lithography process using various types of radiation, particularly a highly integrated circuit element, and a method for forming a dual damascene structure using the same. More specifically, a resist underlayer film forming composition capable of forming a resist underlayer film excellent in embedding properties in vias or trenches and having good pattern transfer performance and etching resistance, and a method for forming a dual damascene structure using the same About.

  2. Description of the Related Art A semiconductor manufacturing process includes a step of sequentially stacking layers of processed films made of a plurality of substances having different characteristics on a silicon wafer and patterning the processed films into a desired pattern. For patterning of the film to be processed, first, a resist film made of a photosensitive substance (resist) is formed on the surface of the film to be processed, and a predetermined region of the resist film is exposed, and then an exposed portion of the resist film or The unexposed portion is removed by development processing to form a resist pattern, and further, the processed film is dry-etched using the resist pattern as an etching mask.

  In such a process, ultraviolet light such as an ArF excimer laser is used as an exposure light source for exposing the resist film. Currently, there is an increasing demand for miniaturization of large-scale integrated circuits (LSIs), and there are cases where the required resolution is less than the wavelength of exposure light. Thus, when the resolution is less than the wavelength of the exposure light, the exposure process tolerance such as the exposure tolerance and the focus tolerance is insufficient. In order to compensate for the shortage of exposure process tolerance, it is effective to improve the resolution by reducing the thickness of the resist film. However, if the thickness of the resist film is reduced, it becomes difficult to secure the resist thickness necessary for etching the film to be processed.

  Therefore, on the surface of the film to be processed, a resist underlayer film (hereinafter sometimes simply referred to as “underlayer film”) is formed, and after the resist pattern is once transferred to the underlayer film to form the underlayer film pattern, A process of transferring this lower layer film pattern to a film to be processed using an etching mask has been studied. Since the lower layer film used in this process preferably has etching resistance, it is proposed to form the lower layer film with a composition containing a polymer having an acenaphthylene skeleton that absorbs energy during etching and exhibits etching resistance. (For example, see Patent Documents 1 to 3).

  By the way, in the case of an LSI pattern rule having a fineness of 0.13 μm or less, the influence of wiring delay on the speeding up of the LSI increases, and the performance enhancement of the LSI will be advanced by the current LSI process technology. Is getting harder. Therefore, in order to reduce the wiring delay, it has been studied to change the wiring material from Al to Cu.

  As a technique for changing the wiring material from Al to Cu, a dual damascene process is known (see, for example, Patent Document 4). In this process, it is necessary to use a substrate having a large aspect ratio (unevenness) as compared with the case where Al is used as the wiring material. The composition for forming a resist underlayer film includes vias and trenches formed on the substrate. However, it is required to have excellent characteristics (embeddability) that can be easily filled.

  As a measure for improving the embedding property of the resist underlayer film forming composition, for example, a method of setting the molecular weight of the resin contained in the composition to 3,000 or less (see, for example, Patent Document 5), [viscosity of the composition The logarithmic change in (mPa · s)] / [change in solid content concentration (mass%)] is 0.06 or less, and the viscosity measured at a solid content concentration of 25 mass% is 1 to 80 mPa · s. There are known a method of s (for example, see Patent Document 6), a method of blending a nitrogen-containing compound (crosslinking agent) having a molecular weight of 800 or less in the composition, and the like (for example, see Patent Document 7).

JP 2000-143937 A JP 2001-40293 A JP 2004-168748 A US Pat. No. 6,057,239 JP 2000-294504 A JP 2003-057828 A JP 2002-329781 A

  However, the method described in Patent Document 5 requires the glass transition temperature of the resin to be 130 ° C. or lower in order to improve the embedding property of the composition. In particular, for a substrate having an aspect ratio of 3 or more, a resin having a glass transition temperature of 130 ° C. or higher could not improve the embeddability even if its molecular weight was lowered.

  On the other hand, when a resin having a glass transition temperature of 130 ° C. or lower is used, the embedding property of the composition is improved, but there is a problem that the etching resistance of the lower layer film, which is an important characteristic along with the embedding property, is insufficient. It was. Further, for a substrate in which vias and trenches are mixed, it has been difficult to exhibit sufficient burying properties in at least both of the vias and the trenches only by reducing the molecular weight of the resin.

  Moreover, the method described in Patent Document 6 has a problem that the etching resistance of the lower layer film is insufficient. In the first place, this method is an invention related to an antireflection film (BARC = Bottom Anti Reflective Coating) that requires lower etching resistance than resist.

  Furthermore, the method described in Patent Document 7 has a problem that the etching resistance of the lower layer film is insufficient. Further, when forming the lower layer film, there is also a problem that the nitrogen-containing compound or a decomposition product thereof is sublimated to contaminate the film forming apparatus.

Thus, at present, there is no disclosure of a composition for forming a resist underlayer film that has the characteristics (fillability) that can be easily filled in the trench formed in the substrate and the etching resistance of the underlayer film.
The present invention is suitable for embedding in a via or a trench, and further, for embedding in at least one of the via and the trench, and is easy to form based on a desired pattern and has a resist underlayer film excellent in etching resistance. An object of the present invention is to provide a resist underlayer film forming composition and a method for efficiently forming a dual damascene structure using the composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have developed a composition for forming a resist underlayer film containing a surfactant having an acetylene group into a via or a trench formed on a substrate. It is suitable for embedding, and at least among vias and trenches, is easy to form based on a desired pattern, provides a resist underlayer film with excellent etching resistance, and has an efficient dual damascene structure. The inventors have found that they can be formed well, and have completed the present invention.

［式中、Ｒ^１は、水素原子又は１価の有機基を示す。Ｒ^２及びＲ^３は、相互に独立して、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。］

［式中、Ｒ^４及びＲ^５は、相互に独立して、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。］

［式中、Ｒ^６は、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。Ｒ^７は、水素原子、炭素数１〜６の置換可能なアルキル基、又は、炭素数１〜６の置換可能なカルボニル基を示す。ｎは０又は１である。］

［式中、Ｒ^８は、水素原子、炭素数１〜６の置換可能なアルキル基、ヒドロキシル基、炭素数１〜６のアルコキシル基、カルボニル基、炭素数１〜６のアルコキシカルボニル基、メチロール基、炭素数１〜６のアルコキシメチロール基を示す。ｎは０〜６の整数である。但し、ｎが２〜６のとき、複数のＲ^８は同一でも異なっていてもよい。Ｘは、メチレン基、炭素数２〜２０の置換可能なアルキレン基、炭素数６〜１４の置換可能なアリーレン基、又はアルキレンエーテル基を示す。ｍは１〜８の整数である。ｍが２〜８のとき、各Ｘは同一でも異なっていてもよい。また、ｎ＋ｍは１〜８の整数である。］
［３］更に、（Ｄ）酸発生剤を含有する上記［２］に記載のレジスト下層膜形成用組成物。
［４］更に、（Ｅ）架橋剤を含有する上記［３］に記載のレジスト下層膜形成用組成物。
［５］前記架橋剤（Ｅ）が、下記一般式（５）で表される化合物、及び、下記一般式（６）で表される化合物のうちの少なくとも一方である上記［４］に記載のレジスト下層膜形成用組成物。

［式中、各Ｒ^９は、同一又は異なって、水素原子、メチル基、ｎ−ブチル基又はイソブチル基を示す。］

［式中、各Ｒ^１０は、同一又は異なって、水素原子、メチル基、ｎ−ブチル基又はイソブチル基を示す。］
［６］前記界面活性剤（Ｂ）が非イオン性である上記［１］乃至［５］のいずれかに記載のレジスト下層膜形成用組成物。
［７］前記界面活性剤（Ｂ）が、エチレンオキサイド部を含む化合物、アセチレンアルコール化合物、及び、アセチレングリコール化合物から選ばれる少なくとも１種である上記［６］に記載のレジスト下層膜形成用組成物。
［８］ビアもしくはトレンチパターンが形成された低誘電絶縁膜を有する基板上に、上記［１］乃至［５］のいずれかに記載のレジスト下層膜用組成物を塗布し、レジスト下層膜を形成する工程と、前記レジスト下層膜上に配置され、レジストパターンが形成されたフォトレジスト膜をマスクとして用いて、前記フォトレジスト膜の前記レジストパターンをエッチングにより前記レジスト下層膜に転写する工程と、前記フォトレジスト膜の前記レジストパターンが転写された前記レジスト下層膜をマスクとして用いて、前記レジスト下層膜の下に配置された低誘電絶縁膜に前記レジスト下層膜の前記レジストパターンを転写する工程と、前記低誘電絶縁膜に前記レジスト下層膜の前記レジストパターンを転写した後、前記レジスト下層膜を除去する工程と、を備えることを特徴とするデュアルダマシン構造の形成方法。 [1] A composition for forming a resist underlayer film used for embedding in a via or a trench, wherein (A) a polymer having an aryl group, (B) a surfactant having an acetylene group, and (C) A composition for forming a resist underlayer film, comprising a solvent.
[2] For forming a resist underlayer film according to [1], wherein the polymer (A) includes at least one selected from the group of structural units represented by the following general formulas (1) to (4): Composition.

[Wherein, R ¹ represents a hydrogen atom or a monovalent organic group. R ² and R ³ each independently represent a hydrogen atom or a C 1-6 substitutable alkyl group. ]

[In formula, R < ⁴ > and R < ⁵ > shows a hydrogen atom or a C1-C6 substitutable alkyl group mutually independently. ]

[Wherein, R ⁶ represents a hydrogen atom or a substitutable alkyl group having 1 to 6 carbon atoms. R ⁷ represents a hydrogen atom, a C 1-6 substitutable alkyl group or a C 1-6 substitutable carbonyl group. n is 0 or 1. ]

[Wherein R ⁸ is a hydrogen atom, a C 1-6 substitutable alkyl group, a hydroxyl group, a C 1-6 alkoxyl group, a carbonyl group, a C 1-6 alkoxycarbonyl group, or a methylol group. And an alkoxymethylol group having 1 to 6 carbon atoms. n is an integer of 0-6. However, when n is 2 to 6, a plurality of R ⁸ may be the same or different. X represents a methylene group, a C 2-20 substitutable alkylene group, a C 6-14 substitutable arylene group, or an alkylene ether group. m is an integer of 1-8. When m is 2 to 8, each X may be the same or different. N + m is an integer of 1-8. ]
[3] The composition for forming a resist underlayer film according to the above [2], further comprising (D) an acid generator.
[4] The resist underlayer film forming composition as described in [3] above, further comprising (E) a crosslinking agent.
[5] The above-mentioned [4], wherein the crosslinking agent (E) is at least one of a compound represented by the following general formula (5) and a compound represented by the following general formula (6). A composition for forming a resist underlayer film.

[In the formula, each R ⁹ is the same or different and represents a hydrogen atom, a methyl group, an n-butyl group or an isobutyl group. ]

[Wherein, each R ¹⁰ is the same or different and represents a hydrogen atom, a methyl group, an n-butyl group or an isobutyl group. ]
[6] The composition for forming a resist underlayer film according to any one of [1] to [5], wherein the surfactant (B) is nonionic.
[7] The composition for forming a resist underlayer film according to [6], wherein the surfactant (B) is at least one selected from a compound containing an ethylene oxide part, an acetylene alcohol compound, and an acetylene glycol compound. .
[8] The resist underlayer film composition according to any one of the above [1] to [5] is applied on a substrate having a low dielectric insulating film in which a via or trench pattern is formed, thereby forming a resist underlayer film Using the photoresist film formed on the resist underlayer film and formed with a resist pattern as a mask, transferring the resist pattern of the photoresist film to the resist underlayer film by etching, and Using the resist underlayer film to which the resist pattern of the photoresist film has been transferred as a mask, transferring the resist pattern of the resist underlayer film to a low dielectric insulating film disposed under the resist underlayer film; After transferring the resist pattern of the resist underlayer film to the low dielectric insulating film, the resist underlayer film is removed. The method for forming a dual damascene structure, characterized in that it comprises a step, to be.

  According to the composition for forming a resist underlayer film of the present invention, it is suitable for embedding in a via or a trench formed in a substrate, and further, for embedding in at least one of the via and the trench. It is easy to form based on the resist underlayer film having excellent etching resistance, and a dual damascene structure can be efficiently formed.

Hereinafter, embodiments of the present invention will be described in detail.
[1] Composition for forming resist underlayer film The composition for forming a resist underlayer film of the present invention is a composition used for embedding in a via or a trench, and further for embedding in at least one of the via and the trench. (A) a polymer having an aryl group (hereinafter referred to as “polymer (A)”), (B) a surfactant having an acetylene group (hereinafter referred to as “surfactant (B)”). And (C) a solvent (hereinafter referred to as “solvent (C)”).

［式中、Ｒ^１は、水素原子又は１価の有機基を示す。Ｒ^２及びＲ^３は、相互に独立して、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。］

［式中、Ｒ^４及びＲ^５は、相互に独立して、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。］

［式中、Ｒ^６は、水素原子又は炭素数１〜６の置換可能なアルキル基を示す。Ｒ^７は、水素原子、炭素数１〜６の置換可能なアルキル基、又は、炭素数１〜６の置換可能なカルボニル基を示す。ｎは０又は１である。］

［式中、Ｒ^８は、水素原子、炭素数１〜６の置換可能なアルキル基、ヒドロキシル基、炭素数１〜６のアルコキシル基、カルボニル基、炭素数１〜６のアルコキシカルボニル基、メチロール基、炭素数１〜６のアルコキシメチロール基を示す。ｎは０〜６の整数である。但し、ｎが２〜６のとき、複数のＲ^８は同一でも異なっていてもよい。Ｘは、メチレン基、炭素数２〜２０の置換可能なアルキレン基、炭素数６〜１４の置換可能なアリーレン基、又はアルキレンエーテル基を示す。ｍは１〜８の整数である。ｍが２〜８のとき、各Ｘは同一でも異なっていてもよい。また、ｎ＋ｍは１〜８の整数である。］
上記重合体（Ａ）は、上記構造単位の１種のみからなる重合体であってよいし、２種以上からなる重合体であってよいし、更には、１種又は２種以上と、他の構造単位とからなる重合体であってもよい。 The polymer (A) is not particularly limited as long as it has an aryl group. Examples of the aryl group include a phenyl group, a benzyl group, a tolyl group, a xylyl group, and a naphthyl group, and a naphthyl group is preferable. In order to obtain excellent etching resistance, this polymer (A) is preferably a polymer having a glass transition temperature of 130 ° C. or higher. Examples of such a polymer include polymers containing structural units represented by the following general formulas (1) to (4).

[Wherein, R ¹ represents a hydrogen atom or a monovalent organic group. R ² and R ³ each independently represent a hydrogen atom or a C 1-6 substitutable alkyl group. ]

[In formula, R < ⁴ > and R < ⁵ > shows a hydrogen atom or a C1-C6 substitutable alkyl group mutually independently. ]

[Wherein, R ⁶ represents a hydrogen atom or a substitutable alkyl group having 1 to 6 carbon atoms. R ⁷ represents a hydrogen atom, a C 1-6 substitutable alkyl group or a C 1-6 substitutable carbonyl group. n is 0 or 1. ]

[Wherein R ⁸ is a hydrogen atom, a C 1-6 substitutable alkyl group, a hydroxyl group, a C 1-6 alkoxyl group, a carbonyl group, a C 1-6 alkoxycarbonyl group, or a methylol group. And an alkoxymethylol group having 1 to 6 carbon atoms. n is an integer of 0-6. However, when n is 2 to 6, a plurality of R ⁸ may be the same or different. X represents a methylene group, a C 2-20 substitutable alkylene group, a C 6-14 substitutable arylene group, or an alkylene ether group. m is an integer of 1-8. When m is 2 to 8, each X may be the same or different. N + m is an integer of 1-8. ]
The polymer (A) may be a polymer composed of only one type of the structural unit, may be a polymer composed of two or more types, and may be one or more types, and others. The polymer which consists of these structural units may be sufficient.

In the structural unit represented by the general formula (1) (hereinafter referred to as “structural unit (1)”), the monovalent organic group represented by R ¹ is preferably a group having 1 to 10 carbon atoms. . Specifically, a phenyl group, an alkyl group, an alkenyl group, an acyl group, or some hydrogen atoms contained in these groups are halogen atoms, hydroxyl groups, mercapto groups, carboxyl groups, nitro groups, sulfonic acid groups. And a functional group substituted with a functional group such as The substituted functional group may be one substituted with two or more functional groups.

  As said alkyl group, a C1-C6 linear or branched alkyl group is preferable. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Moreover, as said alkenyl group, a C2-C6 linear or branched alkenyl group is preferable. Specific examples include a vinyl group, an allyl group, a methallyl group, a 1-butenyl group, and a 2-butenyl group. Further, the acyl group is preferably an aliphatic or aromatic acyl group having 2 to 6 carbon atoms. Specific examples include an acetyl group, a propionyl group, a butyryl group, and a benzoyl group.

In the structural unit (1), examples of the monovalent organic group represented by R ² or R ³ include the groups exemplified as the monovalent organic group represented by R ¹ .

In the structural unit (1), the group represented by R ¹ is preferably a hydrogen atom, a methyl group, or an acetyl group. Further, the group represented by R ² or R ^3, a hydrogen atom, a methyl group, a phenyl group is preferable.

  The polymer having the structural unit (1) can be obtained, for example, by subjecting acenaphthylenes that form the structural unit (1) to radical polymerization, anionic polymerization, cationic polymerization, or the like. These polymerizations can be carried out in conventionally known polymerization forms such as bulk polymerization and solution polymerization. Moreover, you may polymerize acenaphthylenes and another copolymerizable unsaturated compound as needed.

The polymer having the structural unit (1) in which R ¹ is a hydrogen atom is obtained by hydrolyzing the acetoxy group of the polymer having the structural unit (1) in which R ¹ is an acetyl group by a conventional method. Can be manufactured. Further, the polymer having the structural unit (1) in which R ¹ is an acetyl group is obtained by acetylating the hydroxyl group of the polymer having the structural unit (1) in which R ¹ is a hydrogen atom by a conventional method. Can be manufactured.
The polymer having the structural unit (1) has a characteristic of forming a cross-link between molecular chains by heating or exposure.

  As the acenaphthylenes forming the structural unit (1), 3-hydroxymethyl acenaphthylene, 4-hydroxymethyl acenaphthylene, 5-hydroxymethyl acenaphthylene, 1-methyl-3-hydroxymethyl acenaphthylene, 1-methyl-4-hydroxymethylacenaphthylene, 1-methyl-5-hydroxymethylacenaphthylene, 1-methyl-6-hydroxymethylacenaphthylene, 1-methyl-7-hydroxymethylacenaphthylene, 1- Methyl-8-hydroxymethylacenaphthylene, 1,2-dimethyl-3-hydroxymethylacenaphthylene, 1,2-dimethyl-4-hydroxymethylacenaphthylene, 1,2-dimethyl-5-hydroxymethylacenaphthylene Lene, 1-phenyl-3-hydroxymethylacenaphthylene, 1- Enyl-4-hydroxymethylacenaphthylene, 1-phenyl-5-hydroxymethylacenaphthylene, 1-phenyl-6-hydroxymethylacenaphthylene, 1-phenyl-7-hydroxymethylacenaphthylene, 1-phenyl- 8-hydroxymethylacenaphthylene, 1,2-diphenyl-3-hydroxymethylacenaphthylene, 1,2-diphenyl-4-hydroxymethylacenaphthylene, 1,2-diphenyl-5-hydroxymethylacenaphthylene, etc. Of hydroxymethylacenaphthylenes;

  3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene, 5-acetoxymethyl acenaphthylene, 1-methyl-3-acetoxymethyl acenaphthylene, 1-methyl-4-acetoxymethyl acenaphthylene, 1- Methyl-5-acetoxymethylacenaphthylene, 1-methyl-6-acetoxymethylacenaphthylene, 1-methyl-7-acetoxymethylacenaphthylene, 1-methyl-8-acetoxymethylacenaphthylene, 1,2- Dimethyl-3-acetoxymethyl acenaphthylene, 1,2-dimethyl-4-acetoxymethyl acenaphthylene, 1,2-dimethyl-5-acetoxymethyl acenaphthylene, 1-phenyl-3-acetoxymethyl acenaphthylene, 1-phenyl-4-acetoxymethylacenaphthylene, 1-phen 5-5-acetoxymethyl acenaphthylene, 1-phenyl-6-acetoxymethyl acenaphthylene, 1-phenyl-7-acetoxymethyl acenaphthylene, 1-phenyl-8-acetoxymethyl acenaphthylene, 1,2- Acetoxymethylacenaphthylenes such as diphenyl-3-acetoxymethylacenaphthylene, 1,2-diphenyl-4-acetoxymethylacenaphthylene, 1,2-diphenyl-5-acetoxymethylacenaphthylene;

  3-methoxymethylacenaphthylene, 4-methoxymethylacenaphthylene, 5-methoxymethylacenaphthylene, 1-methyl-3-methoxymethylacenaphthylene, 1-methyl-4-methoxymethylacenaphthylene, 1- Methyl-5-methoxymethylacenaphthylene, 1-methyl-6-methoxymethylacenaphthylene, 1-methyl-7-methoxymethylacenaphthylene, 1-methyl-8-methoxymethylacenaphthylene, 1,2- Dimethyl-3-methoxymethyl acenaphthylene, 1,2-dimethyl-4-methoxymethyl acenaphthylene, 1,2-dimethyl-5-methoxymethyl acenaphthylene, 1-phenyl-3-methoxymethyl acenaphthylene, 1-phenyl-4-methoxymethyl acenaphthylene, 1-phenyl-5-methoxymethyl aceto 1-phenyl-6-methoxymethyl acenaphthylene, 1-phenyl-7-methoxymethyl acenaphthylene, 1-phenyl-8-methoxymethyl acenaphthylene, 1,2-diphenyl-3-methoxymethyl acenaphthylene Methoxymethyl acenaphthylenes such as len, 1,2-diphenyl-4-methoxymethyl acenaphthylene, 1,2-diphenyl-5-methoxymethyl acenaphthylene;

3-phenoxymethyl acenaphthylene, 4-phenoxymethyl acenaphthylene, 5-phenoxymethyl acenaphthylene, 3-vinyloxymethyl acenaphthylene, 4-vinyloxymethyl acenaphthylene, 5-vinyloxymethyl acenaphthylene Etc.
These acenaphthylenes can be used singly or in combination of two or more.

  Among the above acenaphthylenes, 3-hydroxymethyl acenaphthylene, 4-hydroxymethyl acenaphthylene, 5-hydroxymethyl acenaphthylene, 3-acetoxymethyl acenaphthylene, 4-acetoxymethyl acenaphthylene, 5-acetoxymethyl Acenaphthylene, 3-methoxymethyl acenaphthylene, 4-methoxymethyl acenaphthylene, 5-methoxymethyl acenaphthylene and the like are preferable.

In the structural unit represented by the general formula (2) (hereinafter referred to as “structural unit (2)”), the monovalent organic group represented by R ⁴ or R ⁵ is the structural unit (1). In the above, groups exemplified as the monovalent organic group represented by R ² or R ³ can be exemplified. R ⁴ or R ⁵ in the structural unit (2) is preferably a hydrogen atom or a methyl group.

  The polymer having the structural unit (2) can be obtained, for example, by subjecting acenaphthylenes that form the structural unit (2) to radical polymerization, anionic polymerization, cationic polymerization, or the like. These polymerizations can be carried out in conventionally known polymerization forms such as bulk polymerization and solution polymerization. Moreover, you may polymerize this acenaphthylene and another copolymerizable unsaturated compound as needed.

Examples of acenaphthylenes that form the structural unit (2) include acenaphthylene and methyl acenaphthylene.
These acenaphthylenes can be used singly or in combination of two or more.

In the structural unit represented by the general formula (3) (hereinafter referred to as “structural unit (3)”), examples of the monovalent organic group for R ⁶ include 1 of R ¹ in the structural unit (1). The groups exemplified for the valent organic group can be applied. Moreover, as the monovalent atom and monovalent organic group of R ⁷ , for example, the groups exemplified for the monovalent atom and monovalent organic group of R ² and R ³ in the structural unit (1), respectively, are applied. be able to.
In the general formula (3), n is 0 or 1.

In the structural unit (3), R ⁶ is particularly preferably a hydrogen atom, a methyl group, or the like. R ⁷ is particularly preferably a hydrogen atom, a methyl group or the like.

  The polymer having the structural unit (3) can be obtained, for example, by subjecting an aromatic vinyl compound that forms the structural unit (3) to radical polymerization, anionic polymerization, cationic polymerization, or the like. These polymerizations can be carried out in conventionally known polymerization forms such as bulk polymerization and solution polymerization. Moreover, you may polymerize an aromatic vinyl type compound and another copolymerizable unsaturated compound as needed.

The polymer having the structural unit (3) in which R ⁶ is a hydrogen atom is obtained by hydrolyzing the acetoxy group of the polymer having the structural unit (3) in which R ⁶ is an acetyl group by a conventional method. Can be manufactured. Further, the polymer having the structural unit (3) in which R ⁶ is an acetyl group is obtained by acetylating the hydroxyl group of the polymer having the structural unit (3) in which R ⁶ is a hydrogen atom by a conventional method. Can be manufactured.

  Examples of the aromatic vinyl compound forming the structural unit (3) include 2-hydroxymethylstyrene, 3-hydroxymethylstyrene, 4-hydroxymethylstyrene, 2-hydroxymethyl-α-methylstyrene, 3-hydroxymethyl- hydroxymethylstyrene compounds such as α-methylstyrene and 4-hydroxymethyl-α-methylstyrene; 2-methoxymethylstyrene, 3-methoxymethylstyrene, 4-methoxymethylstyrene, 2-methoxymethyl-α-methylstyrene, Methoxymethylstyrene compounds such as 3-methoxymethyl-α-methylstyrene and 4-methoxymethyl-α-methylstyrene; 4-phenoxymethylstyrene, 4-phenoxymethyl-α-methylstyrene, 4-vinyloxymethylstyrene, 4-vinyloxime Le -α- methyl styrene, 4-acetoxymethyl styrene, other styrene-based compounds such as 4-acetoxymethyl -α- methyl styrene;

4-hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl-1-vinylnaphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 4-hydroxymethyl-1-isopropenylnaphthalene, 7-hydroxymethyl-1-isopropenyl Hydroxymethyl-1-vinylnaphthalene compounds such as naphthalene and 8-hydroxymethyl-1-isopropenylnaphthalene; 4-methoxymethyl-1-vinylnaphthalene, 7-methoxymethyl-1-vinylnaphthalene, 8-methoxymethyl-1 Methoxymethyl-1-vinylnaphthalene compounds such as vinylnaphthalene, 4-methoxymethyl-1-isopropenylnaphthalene, 7-methoxymethyl-1-isopropenylnaphthalene, 8-methoxymethyl-1-isopropenylnaphthalene; 4- Enoxymethyl-1-vinylnaphthalene, 4-vinyloxymethyl-1-vinylnaphthalene, 4-acetoxymethyl-1-vinylnaphthalene, 4-phenoxymethyl-1-isopropenylnaphthalene, 4-vinyloxymethyl-1-isopropenylnaphthalene And other vinyl naphthalene compounds such as 4-acetoxymethyl-1-isopropenylnaphthalene; and the like.
These aromatic vinyl compounds can be used singly or in combination of two or more.

  Of the aromatic vinyl compounds, 4-hydroxymethylstyrene, 4-methoxymethylstyrene, and the like are preferable.

In the structural unit represented by the general formula (4) (hereinafter referred to as “structural unit (4)”), R ⁸ is a hydrogen atom, a C 1-6 substitutable alkyl group, a hydroxyl group, carbon. An alkoxyl group having 1 to 6 carbon atoms, a carbonyl group, an alkoxycarbonyl group having 1 to 6 carbon atoms, a methylol group, and an alkoxymethylol group having 1 to 6 carbon atoms are shown. n is an integer of 0-6. However, when n is 2 to 6, a plurality of R ⁸ may be the same or different. X represents a methylene group, a C 2-20 substitutable alkylene group, a C 6-14 substitutable arylene group, or an alkylene ether group. m is an integer of 1-8. When m is 2 to 8, a plurality of X may be the same or different. N + m is an integer of 1-8.

In the structural unit (4), R ⁸ is particularly preferably a hydroxyl group. X is particularly preferably a methylene group or the like.

  The content of the structural units represented by the general formulas (1) to (4) (in the case of only one type, the content thereof, and in the case of two or more types, the total amount thereof) is the polymer ( When the total of all structural units constituting A) is 100% by mass, it is usually 5 to 90% by mass, preferably 10 to 80% by mass, and more preferably 20 to 70% by mass. When the polymer (A) having a content of the structural unit of 20 to 70% by mass is used, the embedding property, etching resistance, and low sublimation properties are excellent.

  As described above, the polymer (A) according to the present invention includes a polymer containing at least one selected from the structural units represented by the general formulas (1) to (4) and another structural unit. It may be. Examples of compounds that form other structural units include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, and 9-vinylanthracene. , Other aromatic vinyl compounds such as 9-vinylcarbazole; vinyl ester compounds such as vinyl acetate, vinyl propionate, vinyl caproate; vinyl cyanides such as (meth) acrylonitrile, α-chloroacrylonitrile, vinylidene cyanide, etc. Compounds: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meta ) Acrylate, Good Unsaturated carboxylic acid ester compounds such as ricidyl (meth) acrylate; ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, vinyl (meth) acrylate, dimethyl vinyl (meth) acryloyloxymethylsilane, etc. Unsaturated carboxyl group-containing unsaturated carboxylic acid ester compounds; halogen-containing vinyl compounds such as 2-chloroethyl vinyl ether, vinyl chloroacetate and allyl chloroacetate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Hydroxyl group-containing vinyl compounds such as acrylate and (meth) allyl alcohol; Amido group-containing vinyl compounds such as (meth) acrylamide and crotonic acid amide; Succinic acid mono [2- (meth) acryloyloxyethyl], maleic acid Bruno [2- (meth) acryloyloxyethyl], mono phthalate [2- (meth) acryloyloxyethyl] carboxyl group-containing vinyl such compounds. These compounds can be used alone or in combination of two or more.

  The polystyrene-converted weight average molecular weight (hereinafter sometimes referred to as “Mw”) measured by gel permeation chromatography of the polymer (A) is appropriately selected according to the properties required for the composition. Is preferably 500 to 10,000, more preferably 1,000 to 5,000. By using the composition containing the polymer (A) having this weight average molecular weight within the above range, the coating property is excellent, and the embedding property in vias and trenches formed in the substrate can be improved.

  The content of the polymer (A) contained in the composition for forming a resist underlayer film of the present invention is appropriately selected depending on the purpose, application and the like, but is usually 0.01 with respect to the whole composition. -70 mass%, Preferably it is 0.1-50 mass%. When content of the said polymer (A) exists in the said range, it is excellent in applicability | paintability and can reduce a sublimate.

［式中、Ｒ^１１は、Ｒ−（Ｏ−ＣＨ_２ＣＨ_２）_ｍ−（Ｒは、水素原子、炭素数１〜６の置換可能なアルキル基、又は、置換可能なアリール基であり、ｍは０〜５０の整数である。）である。Ｒ^１２及びＲ^１３は、相互に独立して、炭素数１〜１８のアルキル基である。Ｒ^１４は、水素原子、又は、下記（８）で示される有機基

（式中、Ｒ^１５、Ｒ^１６及びＲ^１７は、それぞれ、Ｒ^１２、Ｒ^１３及びＲ^１１と同様である。）である。］ Although it will not specifically limit as said surfactant (B) if it has an acetylene group, Preferably, it is a nonionic surfactant.
The surfactant (B) is preferably a compound represented by the following general formula (7).

[Wherein, R ¹¹ represents R— (O—CH ₂ CH ₂ ) _m — (R represents a hydrogen atom, a substitutable alkyl group having 1 to 6 carbon atoms, or a substitutable aryl group; Is an integer from 0 to 50). R ¹² and R ¹³ are each independently an alkyl group having 1 to 18 carbon atoms. R ¹⁴ represents a hydrogen atom or an organic group represented by the following (8)

(Wherein R ¹⁵ , R ¹⁶ and R ¹⁷ are the same as R ¹² , R ¹³ and R ¹¹ , respectively). ]

As said surfactant (B), the compound containing an ethylene oxide part, an acetylene alcohol compound, and an acetylene glycol compound are preferable.
The compound containing an ethylene oxide moiety is a compound in the case where R ¹¹ is R— (O—CH ₂ CH ₂ ) _m — and m is an integer of 1 to 50 in the general formula (7). is there. R ¹⁴ is not particularly limited but is preferably an organic group represented by (8) above, and R ¹⁵ , R ¹⁶ and R ¹⁷ are the same as R ¹² , R ¹³ and R ¹¹ , respectively. It is based on.
The acetylene alcohol compound is a compound when R ¹¹ is a hydrogen atom in the general formula (7). R ¹⁴ is not particularly limited, but when R ¹⁷ is a hydrogen atom, it becomes an acetylene glycol compound.

  As the surfactant (B), commercially available products can be used. Specific product names include Surfinol 61, 82, 104, 420, 440, 465, 485, 504, CT-111, CT-121, CT-131, CT-136, CT-141, CT-151. , CT-171, CT-324, DF-37, DF-58, DF-75, DF-110D, DF-210, GA, OP-340, PSA-204, PSA-216, PSA-336, SE, SE -F, Dinol 604, Olphine E1004, E1010, PD-001, PD002W, EXP. 4001, EXP. 4036, EXP. 4051F, SPC, AF-103, AF-104, AK-02, SK-14, AE-3, PD-003, PD201, PD-202, PD-301 (above, manufactured by Nisshin Chemical Co., Ltd. and Air Products) Etc.).

  The content of the surfactant (B) is preferably 0.001 to 15 parts by mass, more preferably 0.01 to 5 parts by mass, and still more preferably 0.001 to 100 parts by mass of the polymer (A). 01 to 1 part by mass. When a composition having a content of this surfactant (B) in the above range is used, it is suitable for embedding in vias and trenches formed in the substrate, and it is easy to form based on a desired pattern, A resist underlayer film having excellent etching resistance can be obtained.

  The solvent (C) is not particularly limited as long as it can dissolve the polymer (A), the surfactant (B), and the additive described later. For example, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate Ethylene glycol monoalkyl ether acetates such as ethylene glycol mono-n-propyl ether acetate and ethylene glycol mono-n-butyl ether acetate; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether Diethylene glycol etc. Alkyl ethers; triethylene glycol dialkyl ethers such as triethylene glycol dimethyl ether and triethylene glycol diethyl ether; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether Propylene glycol monoalkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dialkyl ethers such as propylene glycol di-n-butyl ether; propylene glycol monomethyl ether acetate, propylene glycol Monoether ether Propylene glycol monoalkyl ether acetates such as cetate, propylene glycol mono-n-propyl ether acetate, propylene glycol mono-n-butyl ether acetate; methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, lactic acid Lactic acid esters such as isobutyl; methyl formate, ethyl formate, n-propyl formate, isopropyl formate, n-butyl formate, isobutyl formate, n-amyl formate, isoamyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate , N-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate Aliphatic carboxylic acid esters such as chill, isobutyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, isobutyl butyrate; ethyl hydroxyacetate, ethyl 2-hydroxy-2-methylpropionate , Methyl 3-methoxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate 3-methoxypropyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, Methyl pyruvate, Other esters such as ethyl rubinate; aromatic hydrocarbons such as toluene and xylene; methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, etc. Ketones; amides such as N-methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone; lactones such as γ-butyrolactone; These can be used alone or in combination of two or more.

  Of the above compounds, ethylene glycol monoethyl ether acetate, ethyl lactate, n-butyl acetate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, 2-heptanone, cyclohexanone and the like are preferable.

  The content of the solvent (C) is preferably a solid content concentration of the composition, that is, a ratio of the total amount of components excluding the solvent (C), preferably 0.01 to 70% by mass, more preferably 0.05. It is -60 mass%, More preferably, it is the range used as 0.1-50 mass%.

  The composition for forming a resist underlayer film of the present invention has an acid generator (hereinafter, referred to as “acid generator (D)”), a crosslinking agent (hereinafter, “ Various additives such as a crosslinking agent (E) ”), a radiation absorber, a storage stabilizer, an antifoaming agent, a binder, and an adhesion aid can be blended.

As said acid generator (D), the substance which generate | occur | produces an acid by a chemical stimulus or a physical stimulus is used. For example, a photoacid generator that generates an acid when exposed to light, a thermal acid generator that generates an acid by heating, and the like can be used.
When the composition for forming a resist underlayer film of the present invention contains an acid generator (D), a crosslinked structure is efficiently formed between the molecular chains of the polymer (A) in a relatively low temperature range including normal temperature. be able to.

  Photoacid generators include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, diphenyliodonium Hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-tert-butylphenyl) iodonium n-dodecyl Benzene sulfonate, bis (4-tert-butylphenyl) Dodonium 10-camphorsulfonate, bis (4-tert-butylphenyl) iodonium naphthalenesulfonate, bis (4-tert-butylphenyl) iodonium hexafluoroantimonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butane Sulfonate, triphenylsulfonium n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium hexafluoroantimonate, 4-hydroxyphenyl phenyl methylsulfonium p-toluenesulfonate, 4-hydroxy Phenyl benzyl methylsulfonium p-toluene Sulfonates,

  Cyclohexyl methyl 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldicyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate 4-cyano-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldiethylsulfonium trifluoro Lome Sulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldiethyl Sulfonium trifluoromethanesulfonate,

  1- (4-hydroxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane Sulfonate, 1- [4- (1-methoxyethoxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-methoxyethoxy) naphthalene 1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothio Phenium trifluoromethanesulfonate, 1- (4-n-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate,

  1- (4-isopropoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, (4-tert-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-tetrahydrofuranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, [4- (2-Tetrahydropyranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-benzyloxy) tetrahydrothiophenium trif Oro methanesulfonate, 1-onium salt photoacid generators such as (naphthyl acetamide methyl) tetrahydrothiophenium trifluoromethanesulfonate;

  Halogen-containing compound-based photoacid generators such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine; -1,2-naphthoquinone diazide-4-sulfonic acid ester of 1,3-naphthoquinone diazide-4-sulfonyl chloride, 1,2-naphthoquinone diazide-5-sulfonyl chloride, 2,3,4,4'-tetrahydroxybenzophenone or 1,2, A diazo ketone compound photoacid generator such as naphthoquinonediazide-5-sulfonic acid ester; a sulfone compound photoacid generator such as 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane; benzointosi Rate, pyrogallol tris Trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2,2,1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethane And sulfonic acid compound-based photoacid generators such as sulfonate and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate; These photoacid generators can be used singly or in combination of two or more.

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

Examples of the thermal acid generator include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, and alkyl sulfonates. These thermal acid generators can be used singly or in combination of two or more.
The acid generator (D) may be used in combination with a photoacid generator and a thermal acid generator.

  The content when the acid generator (D) is used is usually 5,000 parts by mass or less, preferably 0.1 when the solid content of the resist underlayer film forming composition of the present invention is 100 parts by mass. To 1,000 parts by mass, more preferably 0.1 to 100 parts by mass.

It does not specifically limit as said crosslinking agent (E), A well-known compound can be used. When the composition for forming a resist underlayer film of the present invention contains a crosslinking agent (E), intermixing between the obtained resist underlayer film and the resist film formed thereon is prevented, and further the resist Cracks in the lower layer film can be prevented.
Examples of the crosslinking agent (E) include a compound having a glycoluril skeleton, a compound having a triazine skeleton, a polynuclear phenol, a diisocyanate compound, an epoxy compound, and a guanamine compound. These can be used alone or in combination of two or more. Of the above, compounds having a glycoluril skeleton and compounds having a triazine skeleton are preferred.

［式中、各Ｒ^９は、同一又は異なって、水素原子、炭素数１〜１０の置換可能なアルキル基を示す。］ Examples of the compound having a glycoluril skeleton include compounds represented by the following general formula (5).

[Wherein, each R ⁹ is the same or different and represents a hydrogen atom or a C 1-10 substitutable alkyl group. ]

In the above general formula (5), when R ⁹ is an alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, etc. Can be mentioned. Of these, a methyl group, an n-butyl group and an isobutyl group are preferable, and an n-butyl group is particularly preferable.

［式中、各Ｒ^１０は、同一又は異なって、水素原子、炭素数１〜１０の置換可能なアルキル基を示す。］ Examples of the compound having a triazine skeleton include compounds represented by the following general formula (6).

[Wherein, each R ¹⁰ is the same or different and represents a hydrogen atom or a substitutable alkyl group having 1 to 10 carbon atoms. ]

In the general formula (6), when R ¹⁰ is an alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, etc. Can be mentioned. Of these, a methyl group, an n-butyl group and an isobutyl group are preferable, and an n-butyl group is particularly preferable.

In the above general formulas (5) and (6), when R ⁹ and R ¹⁰ are both n-butyl groups, sublimation of the crosslinking agent (E) is suppressed, and as a result, contamination of the film forming apparatus is prevented. be able to.

  Examples of the polynuclear phenol include dinuclear phenols such as 4,4′-biphenyldiol, 4,4′-methylene bisphenol, 4,4′-ethylidene bisphenol, and bisphenol A; 4,4 ′, 4 ”-methylidene tris Examples thereof include phenol, trinuclear phenols such as 4,4 ′-[1- [4- {1- (4-hydroxyphenyl) -1-methylethyl} phenyl] ethylidene] bisphenol, and polyphenols such as novolac. These can be used alone or in combination of two or more.

  Examples of the diisocyanate compound include 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 3,4-tolylene diisocyanate, 3,5-tolylene diisocyanate, and 4,4′-diphenylmethane. Examples include diisocyanate, hexamethylene diisocyanate, and 1,4-cyclohexane diisocyanate.

  Examples of the epoxy compound include tris (2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, and the like.

  Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated, and a mixture thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, tetramethylol. Examples thereof include compounds in which 1 to 4 methylol groups of guanamine are acyloxymethylated and mixtures thereof.

  The content when using the crosslinking agent (E) is usually 5,000 parts by mass or less, preferably 0.1 to 1,000 parts by mass, when the polymer (A) is 100 parts by mass. Preferably it is 0.2-20 mass parts.

Examples of the radiation absorber include oil-soluble dyes, disperse dyes, basic dyes, methine dyes, pyrazole dyes, imidazole dyes, hydroxyazo dyes, and the like; bixin derivatives, norbixine, stilbene, 4,4′- Fluorescent brighteners such as diaminostilbene derivatives, coumarin derivatives and pyrazoline derivatives; hydroxyazo dyes, ultraviolet absorbers such as “Tinuvin 234” and “Tinuvin 1130” (trade name) manufactured by Ciba Geigy Corporation; anthracene derivatives, anthraquinone derivatives, etc. An aromatic compound etc. are mentioned. These can be used alone or in combination of two or more.
When using the said radiation absorber, content is 100 mass parts or less normally with respect to 100 mass parts of solid content of the composition for resist underlayer film formation, Preferably it is 50 mass parts or less.

  As the binder, a thermoplastic resin or a thermosetting resin can be used. Examples of the thermoplastic resin include polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-heptene, poly-1-octene, poly-1-decene, and poly-1. Α-olefin polymers such as dodecene, poly-1-tetradecene, poly-1-hexadecene, poly-1-octadecene, polyvinylcycloalkane; poly-1,4-pentadiene, poly-1,4-hexadiene, poly Non-conjugated diene polymers such as -1,5-hexadiene; α, β-unsaturated aldehyde polymers; α, β such as poly (methyl vinyl ketone), poly (aromatic vinyl ketone), poly (cyclic vinyl ketone) -Unsaturated ketone polymer; (meth) acrylic acid, α-chloroacrylic acid, (meth) acrylate, (meth) acrylic acid ester, (meth Polymer of α, β-unsaturated carboxylic acid or derivative thereof such as acrylic acid halide; α, β-unsaturated carboxylic acid anhydride such as poly (meth) acrylic anhydride, maleic anhydride copolymer, etc. Polymer; polymer of unsaturated polybasic carboxylic acid ester such as methylenemalonic acid diester and itaconic acid diester; polymer of diolefin carboxylic acid ester such as sorbic acid ester and muconic acid ester; (meth) acrylic acid thioester; polymer of α, β-unsaturated carboxylic acid thioester such as α-chloroacrylic acid thioester; polymer of (meth) acrylonitrile or derivative thereof such as (meth) acrylonitrile, α-chloroacrylonitrile; (meth) acrylamide, N, The weight of (meth) acrylamide or its derivatives such as N-dimethyl (meth) acrylamide Polymer; polymer of styryl metal compound; polymer of vinyloxy metal compound; polyimine; polyether such as polyphenylene oxide, poly-1,3-dioxolane, polyoxirane, polytetrahydrofuran, polytetrahydropyran; polysulfide; polysulfonamide; polypeptide Polyamides such as nylon 66 and nylon 1 to nylon 12; polyesters such as aliphatic polyester, aromatic polyester, alicyclic polyester, and polycarbonate; polyurea; polysulfone; polyazine; polyamine; polyaromatic ketone; polyimide; Polybenzoxazole; polybenzothiazole; polyaminotriazole; polyoxadiazole; polypyrazole; polytetrazole; polyquinoxaline; ; Polybenzoxazinone; polyquinoline, poly anthrahydroquinone gelsolin; and the like.

  Preferably, the thermosetting resin is cured by heating and becomes insoluble in a solvent, and has an action of preventing intermixing between the resulting resist underlayer film and the photoresist film formed thereon. is there. Examples of the resin having such properties include urea resins, melamine resins, amino resins, aromatic hydrocarbon resins, epoxy resins, alkyd resins, acrylic resins, phenol resins, and the like. Of these thermosetting resins, urea resins, melamine resins, aromatic hydrocarbon resins and the like are preferable.

  The component which comprises the said binder may be single 1 type, and 2 or more types may be sufficient as it. When the composition for forming a resist underlayer film of the present invention contains the binder, the content is usually 20 parts by mass or less, preferably 10 parts by mass or less, with respect to 100 parts by mass of the polymer (A). .

  The method for producing the resist underlayer film forming composition of the present invention is not particularly limited. For example, by dissolving a predetermined amount of the polymer (A) and the surfactant (B) in the solvent (C), If necessary, it can be obtained by subsequent filtration with a filter having a pore size of about 0.1 μm.

  The composition for forming a resist underlayer film of the present invention is embedded in a via or a trench, and further, a substrate comprising at least a trench of the via and the trench and made of a silicon wafer, a wafer covered with aluminum, or the like, or Applying these wafers as a base layer to the surface of the base layer, and applying to the surface of the via or trench, in particular, a composite substrate having a low dielectric insulating layer having at least one of the via and the trench, etc. It is suitable for filling the trench with the composition and forming the resist underlayer film uniformly.

[2] Method for forming dual damascene structure The method for forming a dual damascene structure of the present invention is to apply the resist underlayer film composition of the present invention to a substrate having a low dielectric insulating film in which vias or trench patterns are formed. And etching the resist pattern of the photoresist film using the photoresist film formed on the resist underlayer film and having the resist pattern formed thereon as a mask (see FIG. 5). A step of transferring to the resist underlayer film (see FIG. 6), and using the resist underlayer film to which the resist pattern of the photoresist film is transferred as a mask, a low dielectric constant disposed under the resist underlayer film A step of transferring the resist pattern of the resist underlayer film to the insulating film (a low dielectric insulating layer removing step described later) 7), and after transferring the resist pattern of the resist underlayer film to the low dielectric insulating film, removing the resist underlayer film (see FIG. 8). Furthermore, a dual damascene structure can be obtained by filling the trench formed by this process with a wiring material.

  A method for forming a dual damascene structure according to the present invention will be described in detail. A substrate having a lower wiring portion and vias and trenches formed on the surface of the substrate so that at least a part of the surface of the lower wiring portion is exposed. The resist underlayer film forming composition of the present invention is applied to a multilayer substrate including a low dielectric insulating layer having at least a via and a trench filled with the resist underlayer film forming composition and the surface of the multilayer substrate. A coating film is formed on (application process). Thereafter, the coating film is formed into a film to form a resist underlayer film (resist underlayer film forming step), and a photoresist film is formed on the surface of the resist underlayer film (photoresist film forming step). Next, the photoresist film is processed so that the resist underlayer film forming composition is filled in the vias and the resist underlayer film forming composition is filled in the trench. A resist pattern is formed so that the resist underlayer film disposed on the upper side of the composition filling portion is exposed (resist pattern forming step). Thereafter, using the photoresist film having the resist pattern disposed on the surface of the resist underlayer film as a mask, the exposed resist underlayer film is removed to expose the upper surface of the composition filling portion (resist Pattern transfer step). Next, the photoresist film disposed on the surface of the resist underlayer film is removed (photoresist film removal step), and the resist underlayer film remaining on the surface is used as a mask to form a surface layer of the composition filling portion. And the peripheral portion of the composition filling portion in the low dielectric insulating layer are removed to form a trench for the upper wiring portion (low dielectric insulating layer removing step). Thereafter, the resist underlayer film remaining on the surface and the composition filling portion are removed (resist underlayer film removal step). Next, the trench formed by the resist underlayer film removing step is filled with a wiring material (wiring material filling step) to obtain a dual damascene structure.

The laminated substrate used in the coating process includes a substrate having a lower wiring portion and a low dielectric insulating layer having at least a trench of a via and a trench formed so that at least a part of the surface of the lower wiring portion is exposed. With. The board | substrate which has a lower layer wiring part is not specifically limited, It may be provided with the base layer which has a recessed part, and the lower layer wiring part fitted by this recessed part, Even if it is illustrated by FIG. Good. 4 includes a base layer 11, a first low dielectric insulating layer 12a formed on the surface of the base layer 11, vias formed in the first low dielectric insulating layer 12a, and / or The trench includes a lower layer wiring portion 41 that is filled with a wiring material. In FIG. 4, the barrier metal layer 31 is shown between the lower wiring portion 41 and the base layer 11. However, the presence or absence of the barrier metal layer 31 does not matter in the present invention. The low dielectric insulating layer can be made of silicon oxide, silicon nitride, silicon oxynitride, or the like.
The laminated substrate is illustrated in FIGS. The laminated substrate 2 of FIG. 1 is located above the exposed portion (51, 51) so that at least a part of the surface of the substrate (composite substrate) 1 shown in FIG. 52) and a low dielectric insulating layer 15 formed by opening the holes. However, at least one of the opening portions is a trench. The hole 51 and the hole 52 may be vias or trenches having the same shape and size, or may be vias or trenches having different shapes. Furthermore, the hole 51 may be a via and the hole 52 may be a trench. The shape and size of the via and the trench are not particularly limited.
The multilayer substrate 2 ′ shown in FIG. 2 has openings (51, 52) above the exposed portions so that at least a part of the surface of the substrate (composite substrate) 1 and the lower layer wiring portion 41 of the substrate 1 is exposed. A second low dielectric insulating layer 14a, a third low dielectric insulating layer 16a, and the like. In the multilayer substrate 2 of FIG. 2, an etching stopper film 71a is provided between the second low dielectric insulating layer 14a and the third low dielectric insulating layer 16a.
3 includes an etching stopper film 75a on the surface of the third low dielectric insulating layer 16a in the multilayer substrate 2 ′ of FIG.
Hereinafter, the steps after the coating step in the method for forming a dual damascene structure of the present invention will be described based on a laminated substrate 2 ″ (FIG. 3) in which the hole 51 is a via and the hole 52 is a trench.

  In the coating step, the method for applying the resist underlayer film forming composition is not particularly limited, and known methods such as spin coating, cast coating, and roll coating are applied. By this coating process, the composition fills the holes 51 and 52, which are vias and trenches, without gaps, and a coating film is formed on the surface of the substrate 1. The thickness of the coating film is not particularly limited.

  Thereafter, in the resist underlayer film forming step, the coating film is formed into a film, and the resist underlayer film 6 is obtained (see FIG. 5). In this step, heat treatment (pre-baking) is usually provided to volatilize the solvent (C) contained in the coating film. The temperature of the heat treatment is appropriately selected depending on the constituent components of the coating film, but is usually selected from the range of 90 ° C to 350 ° C, preferably from 200 ° C to 300 ° C. This heat treatment may be performed at a constant temperature in the above range, or may be performed by combining temperature increase and temperature decrease.

  The thickness of the film (resist underlayer film) formed in the resist underlayer film forming step is usually 100 to 2,000 nm, preferably 200 to 500 nm.

  Next, a photoresist film is formed on the surface of the resist underlayer film 6 (photoresist film forming step). The resist composition used for forming this photoresist film is not particularly limited, but includes a positive or negative chemically amplified resist composition containing a photoacid generator; an alkali-soluble resin, a quinonediazide-based photosensitizer, and the like. A positive resist composition containing; a negative resist composition containing an alkali-soluble resin, a crosslinking agent, or the like can be used. When the resist composition is used, a photoresist film can be formed by applying it by a method such as spin coating and drying. The thickness of the photoresist film is not particularly limited.

  Thereafter, in the resist pattern forming step, the photoresist film is processed so that the resist underlayer film forming composition is filled in the vias above the composition filling portion, and the resist underlayer film forming composition. A resist pattern is formed (not shown) so as to expose the resist underlayer film disposed on the upper side of the composition filling portion filled in the trench. For the processing of the photoresist film, a known resist process including exposure, development and the like can be usually applied. In this resist pattern forming step, the photoresist film formed on the surface of the resist underlayer film 6 is processed. Among them, at least a photoresist film in which the composition filling portion is present on the lower side, and usually the composition filling portion and a peripheral portion thereof (a part of the low dielectric insulating layer) are present on the lower side (the above composition). The photoresist film (in a region larger than the filling portion) is removed.

  Next, in the resist pattern transfer step, the resist film 9 having a resist pattern disposed on the surface of the resist underlayer film 6 is used as a mask, and the exposed resist underlayer film is removed to fill the composition. The upper surface of the part is exposed. That is, the resist underlayer film 6 is processed by plasma ashing or the like to remove the film 63 on the upper side of the composition filling portion, and at least the upper surface of the composition filling portion 64, that is, usually the composition filling portion 64. The upper surface and its peripheral edge (a part of the low dielectric insulating layer) are exposed (see FIG. 6). After this step, the photoresist film 9 and the resist underlayer film 62 on the lower layer side remain.

Plasma ashing is an operation that generates a reactive gas plasma such as oxygen plasma to remove a film or the like at a desired position, and decomposes and removes it into CO _x , H ₂ O, etc. in the gas phase. is there.

  The conditions for plasma ashing are appropriately selected, but the high frequency power applied to the susceptor is usually 100 to 1,000 W, preferably 100 to 500 W. The susceptor temperature is preferably 20 ° C to 100 ° C, more preferably 20 ° C to 60 ° C. Furthermore, the pressure in the processing vessel is usually 1 to 300 mTorr, and preferably 30 to 100 mTorr.

  The gas used for plasma ashing is a gas containing at least one selected from the group consisting of nitrogen, hydrogen, ammonia, and argon, which can suppress an increase in the dielectric constant of the low dielectric insulating film due to ashing. Is preferred. Moreover, when using the mixed gas of nitrogen and hydrogen, it is preferable that hydrogen is 0-20 with respect to nitrogen 100 by a volume ratio, and it is still more preferable that hydrogen is 1-10. Moreover, when using the mixed gas of ammonia and argon, it is preferable that argon is 0-10 with respect to ammonia 100 by a volume ratio. The resist underlayer film can be more efficiently removed by such mixed gas plasma. Moreover, it is also preferable that it is a mixed gas of ammonia, nitrogen, and hydrogen.

  Thereafter, in the photoresist film removing step, the photoresist film 9 disposed on the surface of the resist underlayer film 62 is removed.

Next, using the resist underlayer film remaining on the surface as a mask in the low dielectric insulating layer removing step, the surface layer portion of the composition filling portion (the surface layer portion of the composition filling portion in the via, the composition in the trench) The surface layer portion of the filling portion) and the peripheral portion of the composition filling portion in the low dielectric insulating layer are removed to form a trench for the upper wiring portion. Referring to FIG. 6, the etching stopper film 75a, the low dielectric insulating layer 16a, and the composition filling portion exposed at the bottom surface of the groove (concave portion) formed on the upper surface side of the structure in FIG. 64 (portion surrounded by a dotted line in FIG. 6) is removed to obtain the structure of FIG. FIG. 7 shows a substrate (composite substrate) 1 and a second low dielectric insulating layer which is disposed on the surface of the substrate 1 and the composition filling portion 65 is in contact with the upper surface of the lower layer wiring portion 41 of the substrate 1. 14a and an etching stopper disposed between the trench 53 for the upper layer wiring portion having an opening region wider than the upper surface of the composition filling portion 65, and the second low dielectric insulating layer 14a and the third low dielectric insulating layer 16a. It is a schematic sectional drawing provided with the film | membrane 71a.
In this low dielectric insulating layer process, a method such as reactive ion etching can be applied. Regardless of the presence or absence of the etching stopper film 75a, a part of the composition filling portion 64 in FIG. The removal conditions are selected such that 53 is formed.

Thereafter, in the resist underlayer film removing step, the resist underlayer film remaining on the surface and the composition filling portion (the composition filling portion in the via and the composition filling portion in the trench) are removed.
In this resist underlayer film removing step, a method such as plasma ashing can be applied, the resist underlayer film 62 and the composition filling portion 65 in FIG. 7 are removed, and the upper surface of the lower layer wiring portion 41 is exposed, The structure of FIG. 8 is obtained. FIG. 8 shows a substrate (composite substrate) 1 and a hole 51 which is arranged on the surface of the substrate 1 and from which the composition filling portion 65 in FIG. 7 is removed on the upper surface of the lower wiring portion 41 in the substrate 1. Between the second low dielectric insulating layer 14a and the third low dielectric insulating layer 16a. The second low dielectric insulating layer 14a and the trench 53 having an opening region wider than the hole (via) 51. It is a schematic sectional drawing provided with the etching stopper film | membrane 71a.

Next, in the wiring material filling step, the wiring material is filled into the trench (including the via) formed by the resist underlayer film removing step. Before performing this wiring material filling step, a barrier metal film containing TiN, Ta, TaN or the like on the inner surface of the hole 51 and the inner surface of the trench 53 shown in FIG. You may provide the process of forming.
In the wiring material filling step, usually, sputtering, plating, etc. are performed, and the hole 51 and the trench 53 shown in FIG. 8 are filled with a wiring material such as copper (see FIG. 9). FIG. 9 shows an example of a structure in which the wiring material layer 43 is formed as a result of the wiring material filling step. The hole 51 and the trench 53 are filled with the wiring material. Indicates that a part or all of the surface of the etching stopper film 75a is covered.

  The dual damascene structure forming method of the present invention may include a polishing step of smoothing the surface of the wiring material layer 43 by a chemical mechanical polishing method or the like after the wiring material filling step. In this polishing step, the etching stopper film 75a may be removed.

As described above, according to the present invention, the substrate 8 having the dual damascene structure including the lower wiring portion 41, the connection wiring portion 45 and the upper wiring portion 47 joined to the lower wiring portion 41 as shown in FIG. Can be obtained.
In the case where the barrier metal film (33, 35) is formed on the inner surface of the hole 51 and the inner surface of the trench 53 shown in FIG. Then, a substrate 8 ′ having a dual damascene structure as shown in FIG. 11 can be obtained.

  The dual damascene structure is not limited to the one formed by via first, but may be formed by trench first. Moreover, various multilayer wiring structures can be formed by repeating the above steps.

EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.
Moreover, the weight average molecular weights (Mw) of the polymers (A-1), (A-2), (A-3) and the like shown below are GPC columns (“TSK-GEL G2000H _XL : 2” manufactured by Tosoh Corporation). A gel permeation chromatograph using monodisperse polystyrene as a standard under analysis conditions of flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C. (G3000H _XL : 1). (Detector: differential refractometer).

1. Synthesis of Polymer (A) Synthesis Example 1 [Synthesis of Polymer (A-1)]
A separable flask equipped with a thermometer was charged with 8 parts of acenaphthylene, 4 parts of 5-hydroxymethylacenaphthylene, 50 parts of n-butyl acetate and 4 parts of azobisisobutyronitrile in a nitrogen atmosphere while stirring. Polymerization was carried out at 80 ° C. for 7 hours. Thereafter, the reaction solution was diluted with 100 parts of n-butyl acetate, and the organic layer was washed with a large amount of water / methanol (mass ratio = 1/2) mixed solvent. Subsequently, the solvent was distilled off to obtain a polymer (A-1) having an Mw of 1,000.

Synthesis Example 2 [Synthesis of polymer (A-2)]
A separable flask equipped with a thermometer was charged with 7 parts of acenaphthylene, 3 parts of vinylbenzyl alcohol, 60 parts of 1-methoxy-2-propanol and 2 parts of dimethyl 2,2-azobisisobutyrate under a nitrogen atmosphere while stirring. Polymerization was carried out at 80 ° C. for 4 hours. Thereafter, the reaction solution was diluted with 100 parts of n-butyl acetate, and the organic layer was washed with a large amount of water / methanol (mass ratio = 1/2) mixed solvent. Subsequently, the solvent was distilled off to obtain a polymer (A-2) having an Mw of 1,500.

Synthesis Example 3 [Synthesis of polymer (A-3)]
A separable flask equipped with a thermometer was charged with 100 parts of 2,7-dihydroxynaphthalene, 100 parts of propylene glycol monomethyl ether acetate and 50 parts of paraformaldehyde under a nitrogen atmosphere. Thereafter, 2 parts of succinic acid was added, the temperature was raised to 120 ° C. while dehydrating, and the mixture was reacted for 5 hours to obtain a polymer (A-3) having an Mw of 1,500.

2. Preparation and Evaluation of Composition for Forming Resist Underlayer Film Example 1
10 parts of the polymer (A-1) and 0.001 part of “Surfinol 465” (trade name, indicated as “B-1” in Table 1) which is a surfactant (B), 0.5 part of bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate (D-1) as an acid generator (D) and tetrabutoxymethylglycoluril (E) as a crosslinking agent (E) -1, 0.5 parts shown below) was dissolved in 89 parts of n-butyl acetate (C-1) as the solvent (C) to obtain a mixed solution. Thereafter, this mixed solution was filtered through a membrane filter having a pore size of 0.1 μm, and the obtained filtrate was used as a resist underlayer film forming composition.

(1) Evaluation of embedding property The composition for forming a resist underlayer film was obtained by using vias having a size of 100 nm, a pitch of 1H / 1.2S and a depth of 1,000 nm, and a size of 200 nm, a pitch of 1 L / 1S and a depth of 1 Spin coating was performed on a tetraethylorthosilicate (TEOS) substrate on which a trench line of 1,000 nm was formed, and the embedding property in vias and trenches was evaluated by the following method.
After spin-coating the resist underlayer film forming composition, the substrate with the coating film was heated at 200 ° C. for 60 seconds. Thereby, a 300 nm-thick resist underlayer film was formed on the surface of the TEOS substrate. About the produced resist underlayer film, the embedding state of the composition in the via and the trench was observed with a scanning electron microscope. The case where the composition was filled in the via and the trench (when embedded) was determined as good (“◯”), and the case where the composition was not embedded was determined as poor (“×”).

Examples 2-15
A composition for forming a resist underlayer film was prepared and evaluated in the same manner as in Example 1 except that the formulation shown in Table 1 was used. In Table 1, “B-2” is “Dynaflow” (trade name) manufactured by JSR, “C-2” is 1-methoxy-2-acetoxypropane, and “E-2” is n-butyl ether. Hexamethylol melamine, “E-3” tetramethoxymethyl glycoluril, “E-4” is methylolated hexamethylol melamine.

Comparative Examples 1-9
A composition for forming a resist underlayer film was prepared and subjected to various evaluations in the same manner as in Example 1 except that the formulation shown in Table 1 was used. “B-3” in Table 1 is “Mega-Fac R-08” (trade name) manufactured by Dainippon Ink and “B-4” is “Surflon SC-103” (trade name) manufactured by Asahi Glass Co., Ltd. It is.

  As is clear from Table 1, the resist underlayer films formed from the resist underlayer film forming compositions of Examples 1 to 15 were excellent in embedding properties with respect to both vias and trenches. On the other hand, the composition for forming a resist underlayer film of Comparative Examples 1 to 3 had good embedding properties in vias, but was insufficient in embedding properties in trenches. Further, Comparative Examples 4 to 9, which are examples containing B-3 and B-4, which are fluorine-containing surfactants, respectively, had good embedding properties in vias, but poor embedding properties in trenches. It was enough.

  Next, in order to perform various evaluations of the resist underlayer film formed by each of the resist underlayer film forming compositions of Examples 1 to 15 and Comparative Examples 1 to 9, the ArF positive resist composition was changed as follows. Prepared.

In a separable flask equipped with a reflux tube, 8-methyl-8-tert-butoxycarbonylmethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (hereinafter referred to as “monomer (a)”) 29 parts, 8-methyl-8-hydroxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (hereinafter referred to as “monomer (b)”) 10 parts, maleic anhydride (hereinafter referred to as “monomer (c)”) 18 parts, 2, 5 -Charge 4 parts of dimethyl-2,5-hexanediol diacrylate, 1 part of tert-dodecyl mercaptan, 4 parts of azobisisobutyronitrile and 60 parts of 1,2-diethoxyethane for 6 hours at 70 ° C with stirring. Polymerized. Thereafter, the reaction solution was poured into a large amount of a mixed solvent of n-hexane / isopropyl alcohol (mass ratio 1/1) to solidify the resin in the reaction solution. The coagulated resin is washed several times with the mixed solvent and then vacuum-dried, and the structural units derived from each of the monomers (A), (B) and (C) (hereinafter referred to as (a1), (a2 ) And (shown in (a3)). The yield was 60%. This resin contained the structural units (a1), (a2) and (a3) in a molar ratio of 64:18:18, and Mw was 27,000.

  Thereafter, 80 parts of the obtained resin, 1.5 parts of 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 0.04 part of tri-n-octylamine, Was dissolved in 533 parts of propylene glycol monomethyl ether acetate to prepare a resist composition for ArF.

(2) Evaluation of pattern transferability On each resist underlayer film of Examples 1 to 15 and Comparative Examples 1 to 9, an intermediate layer forming composition solution for a three-layer resist process (trade name “NFC SOG302”, manufactured by JSR) Was coated on a hot plate at 200 ° C. for 60 seconds and subsequently heated on a hot plate at 300 ° C. for 60 seconds to form an intermediate layer film having a thickness of 0.05 μm. Thereafter, the ArF resist composition was spin-coated on the intermediate layer film, and pre-baked on a hot plate at 130 ° C. for 90 seconds to form a resist film having a thickness of 0.2 μm. Next, using an ArF excimer laser exposure apparatus (manufactured by NIKON, lens numerical aperture: 0.78, exposure wavelength: 193 nm), exposure was performed through the mask pattern for the optimum exposure time. Thereafter, the film was post-baked for 90 seconds on a 130 ° C. hot plate, and then developed at 25 ° C. for 1 minute using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38%. And it washed with water and dried and obtained the positive resist pattern for ArF. Using this resist pattern as a mask, the intermediate film was processed. Next, the resist underlayer film was processed using the processed intermediate film as a mask. Thereafter, the substrate was processed using the processed resist underlayer film as a mask.
When the pattern formed as described above was observed with a scanning electron microscope (SEM), no defects were found in the pattern shape in any of Examples 1 to 15. However, in Comparative Examples 1 to 9 in which the trench line embeddability was poor, a failure phenomenon such as a pattern falling or a pattern bending was observed.

(3) Etching resistance after substrate processing For each resist underlayer film of Examples 1 to 15 and Comparative Examples 1 to 9, using an etching apparatus (model name “EXAM”, manufactured by Shinko Seiki Co., Ltd.), CF ₄ / Etching was performed with Ar / O ₂ (CF4: 40 mL / min, Ar: 20 mL / min, O ₂ : 5 mL / min; pressure: 20 Pa; RF power: 200 W; treatment time: 40 seconds; temperature: 15 ° C.). The film thickness before and after the etching treatment was measured, the etching rate was calculated, and the etching resistance was evaluated. In all of Examples 1 to 15 and Comparative Examples 1 to 9, the etching rate was good at 150 nm / min or less. It was.

(4) Peelability after substrate processing In order to evaluate the ease of peeling of each resist underlayer film of Examples 1 to 15 and Comparative Examples 1 to 9, fluorination of the resist underlayer film used for forming the positive resist pattern The peelability after the treatment was evaluated by the following method. A resist underlayer film is formed by a spin coating method, and resist is used with CF ₄ (CF ₄ : 100 mL / min; pressure: 30 Pa; RF power: 200 W; treatment time: 60 seconds; temperature: 15 ° C.) using the above etching apparatus. The lower layer film was subjected to a fluorination treatment, and then a peeling treatment by ashing was performed as a peeling treatment. The ashing releasability is the same as that of the resist underlayer film before and after the ashing treatment under the NH ₃ plasma ashing conditions (pressure: 0.1 Torr, high frequency power: 550 W, NH ₃ = 150 sccm, substrate temperature: 20 ° C.) after the fluorination treatment. When the film thickness was measured, in all of Examples 1 to 15 and Comparative Examples 1 to 9, the film thickness became 0 nm in less than 5 minutes after the peeling treatment, and good peelability was exhibited.

  The composition for forming a resist underlayer film of the present invention is suitable for embedding in vias and trenches formed on a substrate, and can be easily formed based on a desired pattern, and provides a resist underlayer film having excellent etching resistance. . Therefore, the resist underlayer film forming composition of the present invention is suitable for forming a highly integrated circuit having a dual damascene structure.

It is a schematic sectional drawing which shows an example of the laminated substrate used for the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows the other example of the laminated substrate used for the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows the other example of the laminated substrate used for the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows an example of the board | substrate (composite type | mold board | substrate) which has a lower layer wiring part. It is a schematic sectional drawing which shows the resist underlayer film formation process in description of the formation method of the dual damascene structure of this invention which used the composition for resist underlayer film formation of this invention with respect to the laminated substrate of FIG. It is a schematic sectional drawing which shows the resist pattern transfer process in description of the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows the low dielectric insulating layer removal process in description of the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows the resist underlayer film removal process in description of the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows the wiring material filling process in description of the formation method of the dual damascene structure of this invention. It is a schematic sectional drawing which shows an example of the board | substrate which has the dual damascene structure obtained by this invention. It is a schematic sectional drawing which shows the other example of the board | substrate which has the dual damascene structure obtained by this invention.

Explanation of symbols

1: Substrate (composite substrate)
11: base layer 12: first low dielectric insulating layer 12a: first low dielectric insulating layer 14: second low dielectric insulating layer 14a: second low dielectric insulating layer 15: low dielectric insulating layer 16: third low dielectric insulating layer 16a : Third low dielectric insulating layer 16b: third low dielectric insulating layer 2, 2 'and 2 ": laminated substrate 31: barrier metal layer 33: barrier metal layer 35: barrier metal layer 41: lower wiring part 43: wiring material layer 45: Connection wiring portion 47: Upper layer wiring portion 51: Hole (via or trench)
52: Hole (via or trench)
53: Trench 6: Resist underlayer film 62: Resist underlayer film 64: Composition filling portion 65: Composition filling portion 71a: Etching stopper film 75a: Etching stopper films 8 and 8 ′: Substrate having dual damascene structure 9: Photoresist film

Claims (8)

  A composition for forming a resist underlayer film used for embedding in a via or a trench, comprising (A) a polymer having an aryl group, (B) a surfactant having an acetylene group, and (C) a solvent A composition for forming a resist underlayer film. The composition for forming a resist underlayer film according to claim 1, wherein the polymer (A) includes at least one selected from the group of structural units represented by the following general formulas (1) to (4).

[Wherein, R ¹ represents a hydrogen atom or a monovalent organic group. R ² and R ³ each independently represent a hydrogen atom or a C 1-6 substitutable alkyl group. ]

[In formula, R < ⁴ > and R < ⁵ > shows a hydrogen atom or a C1-C6 substitutable alkyl group mutually independently. ]

[Wherein, R ⁶ represents a hydrogen atom or a substitutable alkyl group having 1 to 6 carbon atoms. R ⁷ represents a hydrogen atom, a C 1-6 substitutable alkyl group or a C 1-6 substitutable carbonyl group. n is 0 or 1. ]

[Wherein R ⁸ is a hydrogen atom, a C 1-6 substitutable alkyl group, a hydroxyl group, a C 1-6 alkoxyl group, a carbonyl group, a C 1-6 alkoxycarbonyl group, or a methylol group. And an alkoxymethylol group having 1 to 6 carbon atoms. n is an integer of 0-6. However, when n is 2 to 6, a plurality of R ⁸ may be the same or different. X represents a methylene group, a C 2-20 substitutable alkylene group, a C 6-14 substitutable arylene group, or an alkylene ether group. m is an integer of 1-8. When m is 2 to 8, each X may be the same or different. N + m is an integer of 1-8. ]   The composition for forming a resist underlayer film according to claim 2, further comprising (D) an acid generator.   The composition for forming a resist underlayer film according to claim 3, further comprising (E) a crosslinking agent. The resist underlayer film formation according to claim 4, wherein the crosslinking agent (E) is at least one of a compound represented by the following general formula (5) and a compound represented by the following general formula (6). Composition.

[In the formula, each R ⁹ is the same or different and represents a hydrogen atom, a methyl group, an n-butyl group or an isobutyl group. ]

[Wherein, each R ¹⁰ is the same or different and represents a hydrogen atom, a methyl group, an n-butyl group or an isobutyl group. ]   The resist underlayer film forming composition according to any one of claims 1 to 5, wherein the surfactant (B) is nonionic.   The resist underlayer film forming composition according to claim 6, wherein the surfactant (B) is at least one selected from a compound containing an ethylene oxide part, an acetylene alcohol compound, and an acetylene glycol compound. Applying the resist underlayer film composition according to any one of claims 1 to 7 on a substrate having a low dielectric insulating film in which a via or trench pattern is formed, and forming a resist underlayer film;
A step of transferring the resist pattern of the photoresist film to the resist underlayer film by etching, using the photoresist film formed on the resist underlayer film and having a resist pattern as a mask;
Using the resist underlayer film to which the resist pattern of the photoresist film has been transferred as a mask, transferring the resist pattern of the resist underlayer film to a low dielectric insulating film disposed under the resist underlayer film; ,
Transferring the resist pattern of the resist underlayer film to the low dielectric insulating film, and then removing the resist underlayer film;
A method of forming a dual damascene structure, comprising:

Images