JP7258279B2 - Film-forming material for lithography, film-forming composition for lithography, underlayer film for lithography, and pattern forming method - Google Patents

Description

The present invention provides a film-forming material for lithography, a film-forming composition for lithography containing the material, an underlayer film for lithography formed using the composition, and a pattern-forming method using the composition (e.g., a resist pattern). method or circuit pattern method).

2. Description of the Related Art In the manufacture of semiconductor devices, microfabrication is performed by lithography using photoresist materials. In recent years, as the integration density and speed of LSIs have increased, there has been a demand for further miniaturization based on pattern rules. In lithography using photoexposure, which is currently used as a general-purpose technique, the intrinsic resolution limit due to the wavelength of the light source is approaching.

The light source for lithography used for resist pattern formation has been shortened from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). However, as the resist pattern becomes finer and finer, a resolution problem or a problem that the resist pattern collapses after development occurs. However, simply thinning the resist makes it difficult to obtain a resist pattern with a film thickness sufficient for substrate processing. Therefore, in addition to the resist pattern, there is a need for a process in which a resist underlayer film is formed between the resist and the semiconductor substrate to be processed, and this resist underlayer film also functions as a mask during substrate processing.

At present, various types of resist underlayer films are known for such processes. For example, unlike conventional resist underlayer films with a high etching rate, terminal groups are removed by applying a predetermined energy to realize a resist underlayer film for lithography that has a dry etching rate selectivity close to that of resist. An underlayer film-forming material for multi-layer resist processes has been proposed, which contains a solvent and a resin component having at least a substituent group that is separated to form a sulfonic acid residue (see Patent Document 1). In addition, a resist underlayer film material containing a polymer having a specific repeating unit has been proposed as a material for realizing a resist underlayer film for lithography having a dry etching rate selectivity ratio lower than that of a resist (see Patent Document 2). .). Furthermore, in order to realize a resist underlayer film for lithography having a dry etching rate selectivity ratio smaller than that of a semiconductor substrate, acenaphthylene repeating units and repeating units having a substituted or unsubstituted hydroxy group are copolymerized. A resist underlayer film material containing a polymer has been proposed (see Patent Document 3).

On the other hand, an amorphous carbon underlayer film formed by CVD using methane gas, ethane gas, acetylene gas, etc. as raw materials is well known as a material having high etching resistance in this type of resist underlayer film.

In addition, the present inventors have found that a naphthalene formaldehyde polymer containing a specific structural unit and an organic solvent are used as materials that are excellent in optical properties and etching resistance, are soluble in solvents, and can be subjected to wet processes. A film-forming composition has been proposed (see Patent Documents 4 and 5).

Regarding the method of forming the intermediate layer used in the formation of the resist underlayer film in the three-layer process, for example, a method of forming a silicon nitride film (see Patent Document 6) and a method of forming a silicon nitride film by CVD (see Patent Document 7). ) are known. In addition, materials containing silsesquioxane-based silicon compounds are known as intermediate layer materials for three-layer processes (see Patent Documents 8 and 9).

JP-A-2004-177668 JP 2004-271838 A JP-A-2005-250434 WO2009/072465 WO2011/034062 JP-A-2002-334869 WO2004/066377 Japanese Patent Application Laid-Open No. 2007-226170 JP 2007-226204 A

As described above, many film-forming materials for lithography have been proposed in the past, but they not only have high solvent solubility to which wet processes such as spin coating and screen printing can be applied, but also have sublimation resistance during high-temperature baking. There is no material that satisfies all of these requirements at a high level, such as heat resistance, embedding properties in stepped substrates, and film flatness, and the development of new materials is required.

The present invention has been made in view of the above-mentioned problems, and its object is to apply a wet process, and to achieve sublimation resistance, heat resistance, embedding characteristics in stepped substrates, and film flatness during high-temperature baking. A film-forming material for lithography, a composition for forming a film for lithography containing the material, and an underlayer film for lithography and a pattern forming method using the composition, which are useful for forming a photoresist underlayer film excellent in to provide.

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a compound having a specific structure, and have completed the present invention. That is, the present invention is as follows.

（式（１）中、
Ｒは、各々独立して、水素原子及び炭素数１～４のアルキル基からなる群より選ばれる）
を有する化合物を含有し、
前記化合物の分子量が４５０以上である、リソグラフィー用膜形成材料。
［２］
前記式（１）の基を有する化合物が、下記式（１Ａ）で表される、［１］に記載のリソグラフィー用膜形成材料。

（式（１Ａ）中、
Ｘは、それぞれ独立に、単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（ＣＨ₃）₂－、－ＣＯ－、－Ｃ（ＣＦ₃）₂－、－ＣＯＮＨ－又は－ＣＯＯ－であり、
Ａは、単結合、酸素原子、又はヘテロ原子を含んでいてもよい炭素数６～８０の２価の炭化水素基であり、ここで、前記炭化水素基は芳香環を含み、
Ｒ₁は、それぞれ独立に、ヘテロ原子を含んでいてもよい炭素数０～３０の基であり、
ｍ１は、それぞれ独立に、０～４の整数である。）
［３］
Ａが、単結合、酸素原子、又は以下の構造のいずれかであり、

Ｙが単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（ＣＨ₃）₂－、－Ｃ（ＣＦ₃）₂－、

である、
［２］に記載のリソグラフィー用膜形成材料。
［４］
Ｘが、それぞれ独立に、単結合、－Ｏ－、－Ｃ（ＣＨ₃）₂－、－ＣＯ－、又は－ＣＯＯ－であり、
Ａが、単結合、酸素原子、又は以下の構造であり、

Ｙが－Ｃ（ＣＨ₃）₂－又は－Ｃ（ＣＦ₃）₂－である、
［２］又は［３］に記載のリソグラフィー用膜形成材料。
［５］
前記式（１）の基を有する化合物が、下記式（２）又は下記式（３）で表される、［１］に記載のリソグラフィー用膜形成材料。

（式（２）中、
Ｒ₂はそれぞれ独立に、ヘテロ原子を含んでいてもよい炭素数０～１０の基であり、
ｍ２はそれぞれ独立に０～３の整数であり、
ｍ２´はそれぞれ独立に０～４の整数であり、
ｎは１～４の整数である。）

（式（３）中、
Ｒ₃及びＲ₄はそれぞれ独立に、ヘテロ原子を含んでいてもよい炭素数０～１０の基であり、
ｍ３はそれぞれ独立に０～４の整数であり、
ｍ４はそれぞれ独立に０～４の整数であり、
ｎは０～４の整数である。）
［６］
ヘテロ原子が、酸素、フッ素、及びケイ素からなる群より選ばれる、［２］～［５］のいずれかに記載のリソグラフィー用膜形成材料。
［７］
架橋剤をさらに含有する、［１］～［６］のいずれかに記載のリソグラフィー用膜形成材料。
［８］
前記架橋剤が、フェノール化合物、エポキシ化合物、シアネート化合物、アミノ化合物、ベンゾオキサジン化合物、メラミン化合物、グアナミン化合物、グリコールウリル化合物、ウレア化合物、イソシアネート化合物及びアジド化合物からなる群より選ばれる少なくとも１種である、［７］に記載のリソグラフィー用膜形成材料。
［９］
前記架橋剤が、少なくとも１つのアリル基を有する、［７］又は［８］に記載のリソグラフィー用膜形成材料。
［１０］
前記架橋剤の含有割合が、前記式（１）の基を有する化合物の質量を１００質量部とした場合に、０．１～１００質量部である、［７］～［９］のいずれかに記載のリソグラフィー用膜形成材料。
［１１］
架橋促進剤をさらに含有する、［１］～［１０］のいずれかに記載のリソグラフィー用膜形成材料。
［１２］
前記架橋促進剤が、アミン類、イミダゾール類、有機ホスフィン類、及びルイス酸からなる群より選ばれる少なくとも１種である、［１１］に記載のリソグラフィー用膜形成材料。
［１３］
前記架橋促進剤の含有割合が、前記式（１）の基を有する化合物の質量を１００質量部とした場合に、０．１～５質量部である、［１１］又は［１２］に記載のリソグラフィー用膜形成材料。
［１４］
ラジカル重合開始剤をさらに含有する、［１］～［１３］のいずれかに記載のリソグラフィー用膜形成材料。
［１５］
前記ラジカル重合開始剤が、ケトン系光重合開始剤、有機過酸化物系重合開始剤及びアゾ系重合開始剤からなる群より選ばれる少なくとも１種である、［１４］に記載のリソグラフィー用膜形成材料。
［１６］
前記ラジカル重合開始剤の含有割合が、前記式（１）の基を有する化合物の質量を１００質量部とした場合に、０．０５～２５質量部である、［１４］又は［１５］に記載のリソグラフィー用膜形成材料。
［１７］
［１］～［１６］のいずれかに記載のリソグラフィー用膜形成材料と溶媒とを含有する、リソグラフィー用膜形成用組成物。
［１８］
酸発生剤をさらに含有する、［１７］に記載のリソグラフィー用膜形成用組成物。
［１９］
塩基発生剤をさらに含有する、［１７］又は［１８］に記載のリソグラフィー用膜形成用組成物。
［２０］
リソグラフィー用膜がリソグラフィー用下層膜である、［１７］～［１９］のいずれかに記載のリソグラフィー用膜形成用組成物。
［２１］
［２０］に記載のリソグラフィー用膜形成用組成物を用いて形成される、リソグラフィー用下層膜。
［２２］
基板上に、［２０］に記載のリソグラフィー用膜形成用組成物を用いて下層膜を形成する工程、
該下層膜上に、少なくとも１層のフォトレジスト層を形成する工程、及び
該フォトレジスト層の所定の領域に放射線を照射し、現像を行う工程、
を含む、レジストパターン形成方法。
［２３］
基板上に、［２０］に記載のリソグラフィー用膜形成用組成物を用いて下層膜を形成する工程、
該下層膜上に、珪素原子を含有するレジスト中間層膜材料を用いて中間層膜を形成する工程、
該中間層膜上に、少なくとも１層のフォトレジスト層を形成する工程、
該フォトレジスト層の所定の領域に放射線を照射し、現像してレジストパターンを形成する工程、
該レジストパターンをマスクとして前記中間層膜をエッチングする工程、
得られた中間層膜パターンをエッチングマスクとして前記下層膜をエッチングする工程、
得られた下層膜パターンをエッチングマスクとして基板をエッチングすることで基板にパターンを形成する工程、
を含む、パターン形成方法。
［２４］
［１］～［１６］のいずれかに記載のリソグラフィー用膜形成材料を、溶媒に溶解させて有機相を得る工程と、
前記有機相と酸性の水溶液とを接触させて、前記リソグラフィー用膜形成材料中の不純物を抽出する第一抽出工程と、
を含み、
前記有機相を得る工程で用いる溶媒が、水と任意に混和しない溶媒を含む、精製方法。
［２５］
前記酸性の水溶液が、鉱酸水溶液又は有機酸水溶液であり、
前記鉱酸水溶液が、塩酸、硫酸、硝酸及びリン酸からなる群より選ばれる１種以上を含み、
前記有機酸水溶液が、酢酸、プロピオン酸、蓚酸、マロン酸、コハク酸、フマル酸、マレイン酸、酒石酸、クエン酸、メタンスルホン酸、フェノールスルホン酸、ｐ－トルエンスルホン酸及びトリフルオロ酢酸からなる群より選ばれる１種以上を含む、［２４］に記載の精製方法。
［２６］
前記水と任意に混和しない溶媒が、トルエン、２－ヘプタノン、シクロヘキサノン、シクロペンタノン、メチルイソブチルケトン、プロピレングリコールモノメチルエーテルアセテート及び酢酸エチルからなる群より選ばれる１種以上の溶媒である、［２４］又は［２５］に記載の精製方法。
［２７］
前記第一抽出工程後、前記有機相を、水に接触させて、前記リソグラフィー用膜形成材料中の不純物を抽出する第二抽出工程をさらに含む、［２４］～［２６］のいずれかに記載の精製方法。 [1]
A group of the following formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
A film-forming material for lithography, wherein the compound has a molecular weight of 450 or more.
[2]
The film-forming material for lithography according to [1], wherein the compound having the group of formula (1) is represented by the following formula (1A).

(In formula (1A),
Each X is independently a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -CO-, -C(CF ₃ ) ₂ -, -CONH- or -COO- ,
A is a single bond, an oxygen atom, or a divalent hydrocarbon group having 6 to 80 carbon atoms which may contain a heteroatom, wherein the hydrocarbon group contains an aromatic ring,
each R ₁ is independently a group having 0 to 30 carbon atoms which may contain a heteroatom;
Each m1 is independently an integer of 0 to 4. )
[3]
A is a single bond, an oxygen atom, or any of the following structures,

Y is a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -,

is
The film-forming material for lithography according to [2].
[4]
each X is independently a single bond, —O—, —C(CH ₃ ) ₂ —, —CO—, or —COO—;
A is a single bond, an oxygen atom, or the following structure,

Y is -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -
The film-forming material for lithography according to [2] or [3].
[5]
The film-forming material for lithography according to [1], wherein the compound having the group of formula (1) is represented by the following formula (2) or (3).

(In formula (2),
each R ₂ is independently a group having 0 to 10 carbon atoms which may contain a heteroatom;
m2 is each independently an integer of 0 to 3,
each m2' is independently an integer of 0 to 4,
n is an integer of 1-4. )

(In formula (3),
R ₃ and R ₄ are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom,
m3 is each independently an integer of 0 to 4,
m4 is each independently an integer of 0 to 4,
n is an integer of 0-4. )
[6]
The film-forming material for lithography according to any one of [2] to [5], wherein the heteroatom is selected from the group consisting of oxygen, fluorine and silicon.
[7]
The film-forming material for lithography according to any one of [1] to [6], further comprising a cross-linking agent.
[8]
The cross-linking agent is at least one selected from the group consisting of phenol compounds, epoxy compounds, cyanate compounds, amino compounds, benzoxazine compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds and azide compounds. , the film-forming material for lithography according to [7].
[9]
The film-forming material for lithography of [7] or [8], wherein the cross-linking agent has at least one allyl group.
[10]
Any one of [7] to [9], wherein the content of the cross-linking agent is 0.1 to 100 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass. A film-forming material for lithography as described.
[11]
The film-forming material for lithography according to any one of [1] to [10], further comprising a cross-linking accelerator.
[12]
The film-forming material for lithography according to [11], wherein the cross-linking accelerator is at least one selected from the group consisting of amines, imidazoles, organic phosphines, and Lewis acids.
[13]
The content of the cross-linking accelerator is 0.1 to 5 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass, [11] or [12]. Film-forming materials for lithography.
[14]
The film-forming material for lithography according to any one of [1] to [13], further comprising a radical polymerization initiator.
[15]
The film formation for lithography according to [14], wherein the radical polymerization initiator is at least one selected from the group consisting of ketone-based photopolymerization initiators, organic peroxide-based polymerization initiators and azo-based polymerization initiators. material.
[16]
[14] or [15], wherein the content of the radical polymerization initiator is 0.05 to 25 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass. film-forming material for lithography.
[17]
A film-forming composition for lithography, comprising the film-forming material for lithography according to any one of [1] to [16] and a solvent.
[18]
The film-forming composition for lithography according to [17], further comprising an acid generator.
[19]
The film-forming composition for lithography according to [17] or [18], further comprising a base generator.
[20]
The composition for forming a film for lithography according to any one of [17] to [19], wherein the film for lithography is an underlayer film for lithography.
[21]
An underlayer film for lithography, which is formed using the composition for forming a film for lithography according to [20].
[22]
forming an underlayer film on a substrate using the film-forming composition for lithography according to [20];
a step of forming at least one layer of photoresist layer on the underlayer film; and a step of irradiating a predetermined region of the photoresist layer with radiation and developing;
A method of forming a resist pattern, comprising:
[23]
forming an underlayer film on a substrate using the film-forming composition for lithography according to [20];
forming an intermediate layer film on the underlayer film using a resist intermediate layer film material containing silicon atoms;
forming at least one photoresist layer on the intermediate layer film;
a step of irradiating a predetermined region of the photoresist layer with radiation and developing to form a resist pattern;
etching the intermediate layer film using the resist pattern as a mask;
etching the underlayer film using the resulting intermediate layer film pattern as an etching mask;
forming a pattern on the substrate by etching the substrate using the obtained underlayer film pattern as an etching mask;
A method of forming a pattern, comprising:
[24]
a step of dissolving the film-forming material for lithography according to any one of [1] to [16] in a solvent to obtain an organic phase;
a first extraction step of contacting the organic phase with an acidic aqueous solution to extract impurities in the film-forming material for lithography;
including
A purification method, wherein the solvent used in the step of obtaining the organic phase comprises a solvent optionally immiscible with water.
[25]
The acidic aqueous solution is a mineral acid aqueous solution or an organic acid aqueous solution,
The mineral acid aqueous solution contains one or more selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid,
The organic acid aqueous solution is the group consisting of acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, methanesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid and trifluoroacetic acid. The purification method according to [24], including one or more selected from
[26]
The solvent optionally immiscible with water is one or more solvents selected from the group consisting of toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate and ethyl acetate, [24 ] or the purification method according to [25].
[27]
The method according to any one of [24] to [26], further comprising, after the first extraction step, a second extraction step of contacting the organic phase with water to extract impurities in the film-forming material for lithography. purification method.

According to the present invention, a wet process can be applied, and it is useful for forming a photoresist underlayer film that has excellent sublimation resistance, heat resistance, embedding characteristics in stepped substrates, and film flatness during high-temperature baking. A film-forming material for lithography, a film-forming composition for lithography containing the material, and an underlayer film for lithography and a pattern forming method using the composition can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The following embodiments are examples for explaining the present invention, and the present invention is not limited only to these embodiments.

（式（１）中、
Ｒは、各々独立して、水素原子及び炭素数１～４のアルキル基からなる群より選ばれる）
を有する化合物を含有し、
前記化合物の分子量が４５０以上である、リソグラフィー用膜形成材料に関する。 One embodiment of the present invention is a group of formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
It relates to a film-forming material for lithography, wherein the compound has a molecular weight of 450 or more.

A compound having a group of formula (1) (hereinafter also referred to as a "maleimide compound") preferably has two or more groups of formula (1). As the maleimide compound, a compound having two groups of formula (1) and a resin obtained by addition polymerization of a compound having a group of formula (1) are more preferable.

The content of the maleimide compound in the film-forming material for lithography of the present embodiment is preferably 51 to 100% by mass, more preferably 60 to 100% by mass, from the viewpoint of sublimation resistance during high-temperature baking. It is more preferably 70 to 100% by mass, and particularly preferably 80 to 100% by mass.

The maleimide compound in the film-forming material for lithography of this embodiment can also be used as an additive to improve the heat resistance of conventional underlayer film-forming compositions. In that case, the content of the maleimide compound is preferably 1 to 50% by mass, more preferably 1 to 30% by mass.
Examples of conventional underlayer film-forming compositions include, but are not limited to, those described in International Publication 2013/024779.

The maleimide compound in the film-forming material for lithography of the present embodiment is characterized by having a function other than that of an acid generator or basic compound for forming a film for lithography.

The maleimide compound of this embodiment must have a molecular weight of 450 or more. When the molecular weight is 450 or more, the formation of sublimate or decomposed product is suppressed even by high-temperature baking during thin film formation. The molecular weight is preferably 500 or more, more preferably 550 or more, even more preferably 600 or more. Although the upper limit of the molecular weight is not particularly limited, it may be, for example, 2000, 1750, 1500, 1250, 1000 and the like. The molecular weight can be measured by the method described in Examples.

式（１Ａ）中、
Ｘは、それぞれ独立に、単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（ＣＨ₃）₂－、－ＣＯ－、－Ｃ（ＣＦ₃）₂－、－ＣＯＮＨ－又は－ＣＯＯ－であり、
Ａは、単結合、酸素原子、又はヘテロ原子（例えば、酸素、窒素、硫黄、フッ素）を含んでいてもよい炭素数６～８０の２価の炭化水素基であり、ここで、前記炭化水素基は芳香環を含み、
Ｒ₁は、それぞれ独立に、ヘテロ原子（例えば、酸素、窒素、硫黄、フッ素、塩素、臭素、ヨウ素）を含んでいてもよい炭素数０～３０の基であり、
ｍ１はそれぞれ独立に、０～４の整数である。 The maleimide compound of the present embodiment is more preferably a compound represented by the following formula (1A).

In formula (1A),
Each X is independently a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -CO-, -C(CF ₃ ) ₂ -, -CONH- or -COO- ,
A is a single bond, an oxygen atom, or a divalent hydrocarbon group having 6 to 80 carbon atoms which may contain a heteroatom (e.g., oxygen, nitrogen, sulfur, fluorine), wherein the hydrocarbon the group contains an aromatic ring,
each R ₁ is independently a group having 0 to 30 carbon atoms optionally containing a heteroatom (e.g., oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine);
Each m1 is independently an integer of 0-4.

Ｙは単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（ＣＨ₃）₂－、－Ｃ（ＣＦ₃）₂－、

である。 More preferably, from the viewpoint of improving heat resistance, in formula (1A), A is a single bond, an oxygen atom, or any of the following structures,

Y is a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -,

is.

Ｙは－Ｃ（ＣＨ₃）₂－又は－Ｃ（ＣＦ₃）₂－である。 More preferably, in formula (1A),
each X is independently a single bond, —O—, —C(CH ₃ ) ₂ —, —CO—, or —COO—;
A is a single bond, an oxygen atom, or the following structure,

Y is -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -.

X is preferably a single bond from the viewpoint of heat resistance, and preferably -COO- from the viewpoint of solubility.
From the viewpoint of improving heat resistance, Y is preferably a single bond.
R ₁ is preferably a group having 0 to 20 or 0 to 10 carbon atoms which may contain heteroatoms (eg, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine). From the viewpoint of improving solubility in organic solvents, R ₁ is preferably a hydrocarbon group. For example, R ₁ includes an alkyl group (eg, an alkyl group having 1 to 6 or 1 to 3 carbon atoms) and the like, and specific examples include a methyl group, an ethyl group and the like.
m1 is preferably an integer of 0 to 2, more preferably 1 or 2 from the viewpoint of raw material availability and solubility improvement.

From the viewpoint of improving heat resistance, the maleimide compound of the present embodiment is preferably a compound represented by the following formula (2) or the following formula (3).

In formula (2), each R ₂ is independently a group having 0 to 10 carbon atoms which may contain a heteroatom (eg, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine). From the viewpoint of improving solubility in organic solvents, R ₂ is preferably a hydrocarbon group. For example, R ₂ includes an alkyl group (eg, an alkyl group having 1 to 6 or 1 to 3 carbon atoms) and the like, and specific examples include a methyl group and an ethyl group.
Each m2 is independently an integer of 0 to 3. In addition, m2 is preferably 0 or 1, and more preferably 0 from the viewpoint of raw material availability.
Each m2' is independently an integer of 0-4. In addition, m2' is preferably 0 or 1, and more preferably 0 from the viewpoint of raw material availability.
n is an integer from 0 to 4; Also, n is preferably an integer of 1 to 4 or 0 to 2, and more preferably an integer of 1 to 2 from the viewpoint of improving heat resistance.

In the above formula (3), R ₃ and R ₄ are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom (eg, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine); be. From the viewpoint of improving solubility in organic solvents, R ₃ and R ₄ are preferably hydrocarbon groups. Examples of R ₃ and R ₄ include alkyl groups (eg, alkyl groups having 1 to 6 or 1 to 3 carbon atoms) and the like, and specific examples include methyl and ethyl groups.
Each m3 is independently an integer of 0 to 4. Further, m3 is preferably an integer of 0 to 2, and more preferably 0 from the viewpoint of raw material availability.
Each m4 is independently an integer of 0-4. Further, m4 is preferably an integer of 0 to 2, and more preferably 0 from the viewpoint of raw material availability.
n is an integer from 0 to 4; Also, n is preferably an integer of 1 to 4 or 0 to 2, and more preferably an integer of 1 to 2 from the viewpoint of raw material availability.

The film-forming material for lithography of this embodiment can be applied to a wet process. In addition, the film-forming material for lithography of the present embodiment has a rigid aromatic maleimide skeleton, and by satisfying a certain molecular weight standard, it is possible to produce a sublimate or a decomposition product by high-temperature baking during thin film formation. is suppressed. As a result, deterioration of the film during high-temperature baking is suppressed, and an underlayer film having excellent etching resistance can be formed. Furthermore, the film-forming material for lithography of the present embodiment has high solubility in organic solvents and high solubility in safe solvents in spite of having an aromatic structure. Furthermore, the underlayer film for lithography made of the composition for forming a film for lithography according to the present embodiment, which will be described later, is excellent in embedding characteristics in stepped substrates and film flatness, and not only has good stability in product quality, but also resist. Excellent adhesion to the layer and the resist intermediate layer film material makes it possible to obtain an excellent resist pattern.

Specifically, the maleimide compound used in this embodiment is 1,3-bis[2-(4-maleimidophenyl)-2-propyl], 1,3-bis[2-(4-maleimidophenyl) -2-propyl]benzenebis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 1,1-bis(3-ethyl-5-methyl-4-maleimidophenyl)ethane, 2,2-bis( 3-ethyl-5-methyl-4-maleimidophenyl)propane, N,N'-4,4'-[3,3'-dimethyl-diphenylmethane]bismaleimide, N,N'-4,4'-[3 ,3′-dimethyl-1,1-diphenylethane]bismaleimide, N,N′-4,4′-[3,3′-dimethyl-1,1-diphenylpropane]bismaleimide, N,N′-4 ,4′-[3,3′-diethyl-diphenylmethane]bismaleimide, N,N′-4,4′-[3,3′-di-n-propyl-diphenylmethane]bismaleimide, N,N′-4, Diphenylalkane skeleton-containing bismaleimide such as 4′-[3,3′-di-n-butyl-diphenylmethane]bismaleimide; N,N′-4,4′-[3,3′-dimethyl-biphenylene]bismaleimide, biphenyl skeleton-containing bismaleimides such as N,N'-4,4'-[3,3'-diethyl-biphenylene]bismaleimide;

Among the above maleimide compounds, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 1,3-bis[2-(4-maleimidophenyl)-2-propyl]benzene, etc. are particularly resistant to sublimation. and solubility.

As the maleimide compound used in the present embodiment, an addition polymerization type maleimide resin is also preferably used. For example, bismaleimide M-20 (manufactured by Mitsui Toatsu Chemicals, trade name), BMI-2300 (manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name), BMI-3200 (manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name), MIR -3000 (manufactured by Nippon Kayaku Co., Ltd., product name) and the like. Among these, BMI-2300 is particularly preferable because it is excellent in solubility and heat resistance.

<Crosslinking agent>
In addition to the maleimide compound, the film-forming material for lithography of the present embodiment may optionally contain a cross-linking agent from the viewpoint of suppressing a decrease in curing temperature and intermixing.

The cross-linking agent is not particularly limited as long as it undergoes a cross-linking reaction with maleimide, and any known cross-linking system can be applied. compounds, amino compounds, benzoxazine compounds, acrylate compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds, azide compounds and the like, but are not particularly limited thereto. These cross-linking agents can be used singly or in combination of two or more. Among these, a benzoxazine compound, an epoxy compound, or a cyanate compound is preferred, and a benzoxazine compound is more preferred from the viewpoint of improving etching resistance.

In the cross-linking reaction between maleimide and a cross-linking agent, for example, active groups possessed by these cross-linking agents (phenolic hydroxyl group, epoxy group, cyanate group, amino group, or phenolic hydroxyl group obtained by ring-opening the alicyclic moiety of benzoxazine ) undergoes an addition reaction with the carbon-carbon double bond that constitutes the maleimide group to form a crosslink, and the two carbon-carbon double bonds of the bismaleimide compound of the present embodiment polymerize to form a crosslink.

A well-known thing can be used as said phenol compound. For example, those described in WO 2018-016614 can be mentioned. Aralkyl-type phenolic resins are preferable from the viewpoint of heat resistance and solubility.

A known epoxy compound can be used as the epoxy compound, and is selected from those having two or more epoxy groups in one molecule. For example, those described in WO 2018-016614 can be mentioned. Epoxy resins may be used alone or in combination of two or more. From the viewpoint of heat resistance and solubility, epoxy resins that are solid at room temperature, such as epoxy resins obtained from phenol aralkyl resins and biphenyl aralkyl resins, are preferred.

The cyanate compound is not particularly limited as long as it is a compound having two or more cyanate groups in one molecule, and known compounds can be used. For example, those described in International Publication No. 2011-108524 can be mentioned. In the present embodiment, preferred cyanate compounds include a structure in which the hydroxyl group of a compound having two or more hydroxyl groups in one molecule is substituted with a cyanate group. are listed. Moreover, the cyanate compound preferably has an aromatic group, and a cyanate compound having a structure in which the cyanate group is directly linked to the aromatic group can be preferably used. Examples of such cyanate compounds include those described in WO 2018-016614. You may use a cyanate compound individually or in combination of 2 or more types as appropriate. Moreover, the cyanate compound may be in any form of monomer, oligomer and resin.

Examples of the amino compound include those described in WO2018-016614.

The oxazine structure of the benzoxazine compound is not particularly limited, and examples include oxazine structures having an aromatic group including a condensed polycyclic aromatic group, such as benzoxazine and naphthoxazine.

Examples of benzoxazine compounds include compounds represented by the following general formulas (a) to (f). In the general formulas below, the bond shown toward the center of the ring indicates that it is bonded to any carbon that constitutes the ring and to which a substituent can be bonded.

In general formulas (a) to (c), R1 and R2 independently represent an organic group having 1 to 30 carbon atoms. In general formulas (a) to (f), R3 to R6 independently represent hydrogen or a hydrocarbon group having 1 to 6 carbon atoms. In the general formulas (c), (d) and (f), X is independently a single bond, -O-, -S-, -S-S-, -SO ₂ -, -CO-, - CONH-, -NHCO-, -C( _CH3 ) _2- , -C( _CF3 ) _2- , -( _CH2 )m-, -O-( _CH2 )m-O-, -S-(CH ₂ ) represents m-S-. where m is an integer of 1-6. In general formulas (e) and (f), Y is independently a single bond, -O-, -S-, -CO-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - or represents alkylene having 1 to 3 carbon atoms.

Further, benzoxazine compounds include oligomers and polymers having oxazine structures in side chains and oligomers and polymers having benzoxazine structures in main chains.

The benzoxazine compound can be produced by methods similar to those described in WO 2004/009708, JP-A-11-12258, and JP-A-2004-352670.

Examples of the melamine compound include those described in WO2018-016614.

Examples of the guanamine compound include those described in WO2018-016614.

Examples of the glycoluril compound include those described in WO 2018-016614.

Examples of the urea compound include those described in WO2018-016614.

Moreover, in the present embodiment, a cross-linking agent having at least one allyl group may be used from the viewpoint of improving the cross-linkability. Examples of cross-linking agents having at least one allyl group include those described in International Publication No. 2018-016614. The cross-linking agent having at least one allyl group may be used alone or in combination of two or more. From the viewpoint of excellent compatibility with maleimide compounds, 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 1,1,1,3,3,3-hexafluoro-2,2-bis( 3-allyl-4-hydroxyphenyl)propane, bis(3-allyl-4-hydroxyphenyl)sulfone, bis(3-allyl-4-hydroxyphenyl)sulfide, bis(3-allyl-4-hydroxyphenyl)a- Allylphenols such as teru are preferred.

The film-forming material for lithography of the present embodiment can be formed with the maleimide compound alone or after blending with the above-mentioned cross-linking agent, and then cross-linked and cured by a known method to form the film for lithography of the present embodiment. Examples of cross-linking methods include techniques such as heat curing and photo-curing.

The content of the cross-linking agent is usually in the range of 0.1 to 10,000 parts by mass when the mass of the maleimide compound is 100 parts by mass, and is preferably 0.1 from the viewpoint of heat resistance and solubility. ~1000 parts by mass, more preferably 0.1 to 100 parts by mass, still more preferably 1 to 50 parts by mass, most preferably 1 to 30 parts by mass be.

The film-forming material for lithography of the present embodiment may optionally contain a cross-linking accelerator for promoting cross-linking and curing reactions.

The cross-linking accelerator is not particularly limited as long as it promotes cross-linking and curing reaction, and examples thereof include amines, imidazoles, organic phosphines, and Lewis acids. These cross-linking accelerators can be used singly or in combination of two or more. Among these, imidazoles and organic phosphines are preferred, and imidazoles are more preferred from the viewpoint of lowering the cross-linking temperature.

Examples of the cross-linking accelerator include those described in WO 2018-016614.

The amount of the cross-linking accelerator to be blended is generally preferably in the range of 0.1 to 10 parts by mass, and more preferably in terms of ease of control and economy, when the mass of the maleimide compound is 100 parts by mass. From the viewpoint of , it is in the range of 0.1 to 5 parts by mass, more preferably in the range of 0.1 to 3 parts by mass.

The film-forming material for lithography of the present embodiment may optionally contain a latent base generator for promoting cross-linking and curing reactions. One that generates a base by thermal decomposition, one that generates a base by light irradiation, and the like are known, and any of them can be used.

The thermal base generator contains at least one selected from an acidic compound (A1) that generates a base when heated to 40° C. or higher, and an ammonium salt (A2) having an anion with a pKa1 of 0 to 4 and an ammonium cation.
Since the acidic compound (A1) and the ammonium salt (A2) generate bases when heated, the bases generated from these compounds can promote cross-linking and curing reactions. In addition, since these compounds hardly undergo cyclization of the film-forming material for lithography unless they are heated, a highly stable film-forming composition for lithography can be prepared.

A photobase generator is a neutral compound that generates a base upon exposure to electromagnetic radiation. For example, amines that generate benzyl carbamates, benzoin carbamates, O-carbamoyl hydroxylamines, O-carbamoyl oximes, etc., and RR'-N-CO-OR" (wherein R, R' hydrogen or lower alkyl, R″ is nitrobenzyl or α-methyl nitrobenzyl). In particular, a borate compound that generates a tertiary amine or a quaternary ammonium salt containing dithiocarbamate as an anion is used to ensure storage stability when added to a solution and to suppress volatilization during baking due to low vapor pressure. (CE Hoyle, et. al., Macromolecules, 32, 2793 (1999)) and the like are preferable.

Specific examples of the latent base generator include the following, but the present invention is by no means limited to these.
(Examples of hexaammineruthenium (III) triphenylalkylborate) hexaammineruthenium (III) tris (triphenylmethylborate), hexaammineruthenium (III) tris (triphenylethylborate), hexaammineruthenium (III) tris ( triphenylpropylborate), hexaammineruthenium (III) tris (triphenylbutylborate), hexaammineruthenium (III) tris (triphenylhexylborate), hexaammineruthenium (III) tris (triphenyloctylborate), hexaammine Ruthenium (III) Tris (triphenyloctadecylborate), Hexammineruthenium (III) Tris (triphenylisopropylborate), Hexammineruthenium (III) Tris (triphenylisobutylborate), Hexammineruthenium (III) Tris (triphenyl -sec-butylborate), hexaammineruthenium(III) tris(triphenyl-tert-butylborate), hexaammineruthenium(III) tris(triphenylneopentylborate) and the like.
(Examples of hexaammineruthenium (III) triphenylborate) hexaammineruthenium (III) tris (triphenylcyclopentylborate), hexaammineruthenium (III) tris (triphenylcyclohexylborate), hexaammineruthenium (III) tris [tris phenyl(4-decylcyclohexyl)borate], hexaammineruthenium(III) tris[triphenyl(fluoromethyl)borate], hexaammineruthenium(III) tris[triphenyl(chloromethyl)borate], hexaammineruthenium(III) tris [triphenyl(bromomethyl)borate], hexaammineruthenium (III) tris [triphenyl(trifluoromethyl)borate], hexaammineruthenium (III) tris [triphenyl(trichloromethyl)borate], hexaammineruthenium (III) ) tris [triphenyl(hydroxymethyl)borate], hexaammineruthenium (III) tris [triphenyl(carboxymethyl)borate], hexaammineruthenium (III) tris [triphenyl(cyanomethyl)borate], hexaammineruthenium (III) ) tris[triphenyl(nitromethyl)borate], hexaammineruthenium(III) tris[triphenyl(azidomethyl)borate] and the like.
(Examples of hexaammineruthenium (III) triarylbutylborate) hexaammineruthenium (III) tris [tris(1-naphthyl)butylborate], hexaammineruthenium (III) tris [tris(2-naphthyl)butylborate], Hexammineruthenium (III) tris [tris(o-tolyl)butylborate], hexaammineruthenium (III) tris [tris(m-tolyl)butylborate], hexaammineruthenium (III) tris [tris(p-tolyl) butylborate], hexaammineruthenium(III) tris[tris(2,3-xylyl)butylborate], hexaammineruthenium(III) tris[tris(2,5-xylyl)butylborate] and the like.
(Examples of ruthenium (III) tris (triphenylbutylborate)) tris (ethylenediamine) ruthenium (III) tris (triphenylbutylborate), cis-diamminebis (ethylenediamine) ruthenium (III) tris (triphenylbutylborate), trans-diamminebis(ethylenediamine)ruthenium(III)tris(triphenylbutylborate), tris(trimethylenediamine)ruthenium(III)tris(triphenylbutylborate), tris(propylenediamine)ruthenium(III)tris(triphenyl butylborate), tetraammine {(-) (propylenediamine)} ruthenium (III) tris (triphenylbutylborate), tris (trans-1,2-cyclohexanediamine) ruthenium (III) tris (triphenylbutylborate), bis (diethylenetriamine) ruthenium (III) tris (triphenylbutylborate), bis (pyridine) bis (ethylenediamine) ruthenium (III) tris (triphenylbutylborate), bis (imidazole) bis (ethylenediamine) ruthenium (III) tris (tri phenylbutyl borate) and the like.
The above-described base generator (A) is prepared by adding a halogen salt, sulfate, nitrate, acetate, etc. of each complex ion and an alkali metal borate salt in an appropriate solvent such as water, alcohol, or a water-containing organic solvent. , can be easily produced by mixing. Halogen salts, sulfates, nitrates, acetates, etc. of these complex ions, which are the raw materials, are readily available as commercial products. III), Maruzen (1977), etc. describe the synthesis method thereof.

The content of the latent base generator may be a stoichiometrically necessary amount with respect to the mass of the maleimide compound, but is 0.01 when the mass of the maleimide compound is 100 parts by mass. It is preferably from 0.01 to 10 parts by mass, more preferably from 0.01 to 10 parts by mass. When the content of the latent base generator is 0.01 parts by mass or more, it tends to be possible to prevent insufficient curing of the maleimide compound. When the content of the agent is 25 parts by mass or less, it tends to be possible to prevent deterioration of the long-term storage stability at room temperature of the film-forming material for lithography.

<Radical polymerization initiator>
The film-forming material for lithography of the present embodiment may optionally contain a radical polymerization initiator. The radical polymerization initiator may be a photopolymerization initiator that initiates radical polymerization with light, or a thermal polymerization initiator that initiates radical polymerization with heat.

Examples of such radical polymerization initiators include those described in WO 2018-016614. As the radical polymerization initiator in the present embodiment, one type may be used alone, or two or more types may be used in combination.

The content of the radical polymerization initiator may be a stoichiometrically necessary amount with respect to the mass of the maleimide compound. It is preferably 25 parts by mass, more preferably 0.1 to 10 parts by mass. When the content of the radical polymerization initiator is 0.05 parts by mass or more, it tends to be possible to prevent insufficient curing of the maleimide compound. When it is not more than parts by mass, it tends to be possible to prevent deterioration of long-term storage stability at room temperature of the film-forming material for lithography.

[Method for Purifying Film-Forming Material for Lithography]
The lithographic film-forming material can be purified by washing with an acidic aqueous solution. In the purification method, the film-forming material for lithography is dissolved in an organic solvent that is arbitrarily immiscible with water to obtain an organic phase, and the organic phase is brought into contact with an acidic aqueous solution to perform an extraction treatment (first extraction step). 3. Transferring metals contained in an organic phase containing a film-forming material for lithography and an organic solvent to an aqueous phase, and then separating the organic phase from the aqueous phase. The purification can significantly reduce the content of various metals in the film-forming material for lithography of the present invention.

The organic solvent that is arbitrarily immiscible with water is not particularly limited, but an organic solvent that can be safely applied to the semiconductor manufacturing process is preferable. The amount of the organic solvent used is usually about 1 to 100 times the weight of the compound used.

Specific examples of the organic solvent used include those described in International Publication 2015/080240. Among these, toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethyl acetate and the like are preferred, and cyclohexanone and propylene glycol monomethyl ether acetate are particularly preferred. These organic solvents can be used alone or in combination of two or more.

The acidic aqueous solution is appropriately selected from aqueous solutions in which generally known organic and inorganic compounds are dissolved in water. Examples include those described in International Publication 2015/080240. Each of these acidic aqueous solutions can be used alone, or two or more of them can be used in combination. Examples of acidic aqueous solutions include mineral acid aqueous solutions and organic acid aqueous solutions. Examples of the aqueous mineral acid solution include aqueous solutions containing one or more selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid. Examples of aqueous organic acid solutions include acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, methanesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid and trifluoroacetic acid. An aqueous solution containing one or more selected from the group consisting of The acidic aqueous solution is preferably an aqueous solution of sulfuric acid, nitric acid, or a carboxylic acid such as acetic acid, oxalic acid, tartaric acid, or citric acid, more preferably an aqueous solution of sulfuric acid, oxalic acid, tartaric acid, or citric acid, and particularly an aqueous solution of oxalic acid. preferable. Polyvalent carboxylic acids such as oxalic acid, tartaric acid, and citric acid coordinate to metal ions and produce a chelating effect, so it is believed that more metals can be removed. Further, the water used here is preferably one having a low metal content, such as ion-exchanged water, in line with the object of the present invention.

The pH of the acidic aqueous solution is not particularly limited, but if the acidity of the aqueous solution is too high, it may adversely affect the compounds or resins used, which is not preferred. The pH range is usually about 0-5, more preferably about 0-3.

The amount of the acidic aqueous solution used is not particularly limited. may cause the above problem. The amount of the aqueous solution used is usually 10 to 200 parts by mass, preferably 20 to 100 parts by mass, based on the solution of the film-forming material for lithography.

The metal content can be extracted by contacting the acidic aqueous solution with a solution (B) containing a film-forming material for lithography and an organic solvent optionally immiscible with water.

The temperature at which the extraction treatment is performed is usually 20 to 90°C, preferably 30 to 80°C. The extraction operation is performed, for example, by mixing well by stirring or the like, and then allowing the mixture to stand still. As a result, the metal contained in the solution containing the compound used and the organic solvent migrates to the aqueous phase. Moreover, this operation reduces the acidity of the solution, and can suppress deterioration of the compound to be used.

After the extraction treatment, the solution phase containing the compound to be used and the organic solvent is separated from the aqueous phase, and the solution containing the organic solvent is recovered by decantation or the like. The standing time is not particularly limited, but if the standing time is too short, the separation between the solution phase containing the organic solvent and the aqueous phase becomes poor, which is not preferred. Usually, the standing time is 1 minute or longer, preferably 10 minutes or longer, and still more preferably 30 minutes or longer. The extraction process may be performed only once, but it is also effective to repeat the operations of mixing, standing, and separating multiple times.

When such extraction treatment is performed using an acidic aqueous solution, the organic phase containing the recovered organic solvent is extracted from the aqueous solution after the treatment, and the recovered organic phase is further subjected to extraction treatment with water (second extraction step) is preferably performed. The extraction operation is performed by allowing the mixture to stand still after mixing well by stirring or the like. Since the obtained solution is separated into a solution phase containing the compound and the organic solvent and an aqueous phase, the solution phase is recovered by decantation or the like. Further, the water used here is preferably one having a low metal content, such as ion-exchanged water, in line with the object of the present invention. The extraction process may be performed only once, but it is also effective to repeat the operations of mixing, standing, and separating multiple times. In addition, conditions such as the ratio of both of them used in the extraction treatment, temperature, and time are not particularly limited, but they may be the same as in the case of the contact treatment with the acidic aqueous solution.

Water contained in the thus obtained solution containing the film-forming material for lithography and the organic solvent can be easily removed by performing an operation such as distillation under reduced pressure. Also, if necessary, an organic solvent can be added to adjust the concentration of the compound to an arbitrary concentration.

Methods for obtaining only the film-forming material for lithography from the obtained solution containing the organic solvent can be carried out by known methods such as removal under reduced pressure, separation by reprecipitation, and combinations thereof. If necessary, known treatments such as concentration operation, filtration operation, centrifugation operation, and drying operation can be performed.

[Composition for film formation for lithography]
The film-forming composition for lithography of this embodiment contains the film-forming material for lithography and a solvent. The lithographic film is, for example, a lithographic underlayer film.

The film-forming composition for lithography of the present embodiment can be applied to a substrate, then optionally heated to evaporate the solvent, and then heated or irradiated to form a desired cured film. can. The film-forming composition for lithography of the present embodiment may be applied by any method. A roll coating method, transfer printing method, brush coating method, blade coating method, air knife coating method, or the like can be used as appropriate.

The heating temperature of the film is not particularly limited for the purpose of evaporating the solvent, and can be, for example, 40 to 400.degree. The heating method is not particularly limited. For example, a hot plate or an oven may be used to evaporate under an appropriate atmosphere such as air, an inert gas such as nitrogen, or vacuum. The heating temperature and heating time may be selected so as to suit the process steps of the intended electronic device, and the heating conditions may be selected such that the physical properties of the resulting film are suitable for the required properties of the electronic device. The conditions for light irradiation are not particularly limited, either, and suitable irradiation energy and irradiation time may be adopted according to the film-forming material for lithography to be used.

<Solvent>
The solvent used in the film-forming composition for lithography of the present embodiment is not particularly limited as long as it dissolves at least the maleimide compound, and known solvents can be used as appropriate.

Specific examples of the solvent include those described in International Publication 2013/024779. These solvents can be used singly or in combination of two or more.

Among the above solvents, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl hydroxyisobutyrate, and anisole are particularly preferred from the viewpoint of safety.

The content of the solvent is not particularly limited, but from the viewpoint of solubility and film formation, it is 25 to 9,900 parts by mass when the mass of the maleimide compound in the film-forming material for lithography is 100 parts by mass. , more preferably 400 to 7,900 parts by mass, and even more preferably 900 to 4,900 parts by mass.

<Acid generator>
The film-forming composition for lithography of the present embodiment may optionally contain an acid generator from the viewpoint of further promoting the cross-linking reaction. As acid generators, those that generate acid by thermal decomposition, those that generate acid by light irradiation, and the like are known, and any of them can be used.

Examples of acid generators include those described in International Publication 2013/024779. Among these, in particular, ditertiarybutyldiphenyliodonium nonafluoromethanesulfonate, diphenyliodonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)phenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, p- (p-tert-butoxyphenyl)phenyliodonium toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)trifluoromethanesulfonate Sulfonium, triphenylsulfonium p-toluenesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium p-toluenesulfonate, tris(p-tert-butoxyphenyl)sulfonium p-toluenesulfonate, trinaphthylsulfonium trifluoromethanesulfonate , cyclohexylmethyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, (2-norbornyl)methyl(2-oxocyclohexyl)sulfonium trifluoromethanesulfonate, onium such as 1,2′-naphthylcarbonylmethyltetrahydrothiophenium triflate Salt; bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(sec-butylsulfonyl)diazomethane, Diazomethane derivatives such as bis(n-propylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethane; bis-(p-toluenesulfonyl)-α-dimethylglyoxime, bis-(n-butane) glyoxime derivatives such as sulfonyl)-α-dimethylglyoxime, bissulfone derivatives such as bisnaphthylsulfonylmethane; N-hydroxysuccinimide methanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide 1-propanesulfonic acid ester, N-hydroxysuccinimide 2-propanesulfonate, N-hydroxysuccinimide 1-pentanesulfonate, N-hydroxysuccinimide p-toluenesulfonate, N-hydroxynaphthalimide methanesulfonate, N-hydroxynaphthalimide Sulfonic acid ester derivatives of N-hydroxyimide compounds such as benzenesulfonic acid esters are preferably used.

In the film-forming composition for lithography of the present embodiment, the content of the acid generator is not particularly limited, but is 0 to 50 mass parts when the mass of the maleimide compound in the film-forming material for lithography is 100 parts by mass. parts, more preferably 0 to 40 parts by mass. By setting it within the preferred range described above, the cross-linking reaction tends to be enhanced, and the occurrence of the mixing phenomenon with the resist layer tends to be suppressed.

<Basic compound>
Furthermore, the composition for forming an underlayer film for lithography of the present embodiment may contain a basic compound from the viewpoint of improving storage stability.

The basic compound serves as a quencher for the acid to prevent the progress of the cross-linking reaction of the acid generated in a small amount by the acid generator. Such basic compounds include, but are not limited to, primary, secondary or tertiary aliphatic amines, mixed amines, aromatic group amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amide derivatives or and imide derivatives.

In the film-forming composition for lithography of the present embodiment, the content of the basic compound is not particularly limited. part, more preferably 0 to 1 part by mass. When the content is within the preferred range described above, the storage stability tends to be enhanced without excessively impairing the cross-linking reaction.

Furthermore, the film-forming composition for lithography of the present embodiment may contain known additives. Examples of known additives include, but are not limited to, ultraviolet absorbers, antifoaming agents, colorants, pigments, nonionic surfactants, anionic surfactants, cationic surfactants, and the like.

[Underlayer film for lithography and pattern forming method]
The underlayer film for lithography of this embodiment is formed using the film-forming composition for lithography of this embodiment.

Further, the pattern forming method of the present embodiment includes the step (A-1) of forming an underlayer film on a substrate using the film-forming composition for lithography of the present embodiment, and on the underlayer film, at least one a step (A-2) of forming a photoresist layer of a layer, and a step (A-3) of, after the step (A-2), irradiating a predetermined region of the photoresist layer with radiation and developing the , has

Furthermore, another pattern forming method of the present embodiment includes the step (B-1) of forming an underlayer film on a substrate using the film-forming composition for lithography of the present embodiment; Step (B-2) of forming an intermediate layer film using a resist intermediate layer film material containing silicon atoms; and Step (B-3) of forming at least one photoresist layer on the intermediate layer film. and, after the step (B-3), a step (B-4) of irradiating a predetermined region of the photoresist layer with radiation and developing to form a resist pattern; Thereafter, the intermediate layer film is etched using the resist pattern as a mask, the lower layer film is etched using the obtained intermediate layer film pattern as an etching mask, and the substrate is etched using the obtained lower layer film pattern as an etching mask. and a step (B-5) of forming a pattern on the substrate.

As long as the underlayer film for lithography of this embodiment is formed from the film-forming composition for lithography of this embodiment, the formation method is not particularly limited, and known techniques can be applied. For example, after the film-forming composition for lithography of the present embodiment is applied onto a substrate by a known coating method such as spin coating or screen printing or a printing method, the organic solvent is removed by, for example, volatilization. An underlayer film can be formed.

When forming the lower layer film, it is preferable to perform baking in order to suppress the occurrence of the mixing phenomenon with the upper layer resist and promote the cross-linking reaction. In this case, the baking temperature is not particularly limited, but is preferably in the range of 80 to 450.degree. C., more preferably 200 to 400.degree. Also, the baking time is not particularly limited, but is preferably within the range of 10 to 300 seconds. The thickness of the underlayer film can be appropriately selected according to the required performance, and is not particularly limited. It is more preferably 50 to 1000 nm.

After forming the underlayer film on the substrate, a silicon-containing resist layer or a conventional hydrocarbon monolayer resist is formed thereon in the case of a two-layer process, and a silicon-containing intermediate layer is formed thereon in the case of a three-layer process, and further It is preferable to form a silicon-free monolayer resist layer thereon. In this case, a known photoresist material can be used for forming this resist layer.

As a silicon-containing resist material for a two-layer process, from the viewpoint of oxygen gas etching resistance, a silicon atom-containing polymer such as a polysilsesquioxane derivative or a vinylsilane derivative is used as a base polymer, and an organic solvent, an acid generator, A positive photoresist material containing a basic compound or the like, if necessary, is preferably used. Here, as the silicon atom-containing polymer, a known polymer used in this type of resist material can be used.

A polysilsesquioxane-based intermediate layer is preferably used as the silicon-containing intermediate layer for the three-layer process. Reflection tends to be effectively suppressed by providing the intermediate layer with an antireflection film effect. For example, in a 193 nm exposure process, if a material containing many aromatic groups and having high substrate etching resistance is used as the underlayer film, the k value tends to increase and the substrate reflection tends to increase. can reduce the substrate reflection to 0.5% or less. The intermediate layer having such an antireflection effect is not limited to the following, but for 193 nm exposure, an acid- or heat-crosslinkable polysilsesquioxylate having a phenyl group or a silicon-silicon bond-containing light-absorbing group is introduced. Sun is preferably used.

An intermediate layer formed by a chemical vapor deposition (CVD) method can also be used. Although not limited to the following, for example, a SiON film is known as an intermediate layer that is highly effective as an antireflection film produced by a CVD method. In general, forming an intermediate layer by a wet process such as a spin coating method or screen printing is simpler and more cost effective than a CVD method. The upper layer resist in the three-layer process may be either positive type or negative type, and may be the same as a commonly used single layer resist.

Further, the underlayer film of the present embodiment can also be used as an antireflection film for a normal single-layer resist or as a base material for suppressing pattern collapse. Since the underlayer film of the present embodiment is excellent in etching resistance for underlayer processing, it can be expected to function as a hard mask for underlayer processing.

When the resist layer is formed from the photoresist material, a wet process such as spin coating or screen printing is preferably used as in the case of forming the underlayer film. After the resist material is applied by spin coating or the like, prebaking is usually performed, and it is preferable to perform this prebaking at 80 to 180° C. for 10 to 300 seconds. After that, exposure, post-exposure baking (PEB), and development are carried out according to a conventional method, whereby a resist pattern can be obtained. Although the thickness of the resist film is not particularly limited, it is generally preferably 30 to 500 nm, more preferably 50 to 400 nm.

Also, the exposure light may be appropriately selected and used according to the photoresist material to be used. In general, high-energy rays with a wavelength of 300 nm or less, specifically excimer lasers of 248 nm, 193 nm and 157 nm, soft X-rays of 3 to 20 nm, electron beams, X-rays and the like can be used.

In the resist pattern formed by the above-described method, pattern collapse is suppressed by the underlayer film of the present embodiment. Therefore, by using the underlayer film of this embodiment, a finer pattern can be obtained, and the exposure dose required for obtaining the resist pattern can be reduced.

Next, etching is performed using the obtained resist pattern as a mask. Gas etching is preferably used for etching the lower layer film in the two-layer process. As the gas etching, etching using oxygen gas is suitable. In addition to oxygen gas, it is also possible to add inert gases such as He and Ar, and CO, _CO2 , _NH3 , _SO2 , _N2 , _NO2 and _H2 gases. Gas etching can also be performed using only CO, _CO2 , _NH3 , _N2 , NO2, and _H2 gases without using oxygen gas. In particular, the latter gas is preferably used for sidewall protection to prevent undercutting of pattern sidewalls.

On the other hand, gas etching is also preferably used for etching the intermediate layer in the three-layer process. As the gas etching, the same one as described in the above two-layer process can be applied. In particular, it is preferable to process the intermediate layer in the three-layer process using a freon-based gas and using a resist pattern as a mask. After that, as described above, the intermediate layer pattern is used as a mask to perform, for example, oxygen gas etching, whereby the lower layer film can be processed.

Here, when an inorganic hard mask intermediate layer film is formed as the intermediate layer, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) is formed by a CVD method, an ALD method, or the like. The method for forming the nitride film is not limited to the following, but for example, the methods described in Japanese Patent Application Laid-Open No. 2002-334869 (Patent Document 6) and WO2004/066377 (Patent Document 7) can be used. Although a photoresist film can be directly formed on such an intermediate layer film, an organic anti-reflective coating (BARC) is formed on the intermediate layer film by spin coating, and a photoresist film is formed thereon. You may

As an intermediate layer, a polysilsesquioxane-based intermediate layer is also preferably used. Reflection tends to be effectively suppressed by giving the resist intermediate layer film an effect as an antireflection film. Specific materials for the polysilsesquioxane-based intermediate layer are not limited to the following, but are described in, for example, JP-A-2007-226170 (Patent Document 8) and JP-A-2007-226204 (Patent Document 9). can be used.

Etching of the next substrate can also be carried out by a conventional method. For example, if the substrate is SiO ₂ or SiN, etching mainly using Freon-based gas, and for p-Si, Al, or W, chlorine-based or bromine-based etching is performed. Gas-based etching can be performed. When the substrate is etched with Freon-based gas, the silicon-containing resist in the two-layer resist process and the silicon-containing intermediate layer in the three-layer process are stripped at the same time as the substrate is processed. On the other hand, when the substrate is etched with a chlorine-based or bromine-based gas, the silicon-containing resist layer or the silicon-containing intermediate layer is removed separately, and generally, after the substrate is processed, the dry-etching removal is performed with a flon-based gas. .

The underlayer film of the present embodiment is characterized by being excellent in etching resistance of these substrates. The substrate can be appropriately selected and used from known substrates, and is not particularly limited _. . The substrate may also be a laminate having a film to be processed (substrate to be processed) on a base material (support). Such films to be processed include various Low-k films such as Si, SiO ₂ , SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, and Al-Si, and their stopper films. etc., and usually a material different from that of the substrate (support) is used. Although the thickness of the substrate to be processed or the film to be processed is not particularly limited, it is generally preferably about 50 to 1,000,000 nm, more preferably 75 to 500,000 nm.

Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to these examples.

[Molecular weight]
The molecular weights of the synthesized compounds were measured by LC-MS analysis using Acquity UPLC/MALDI-Synapt HDMS manufactured by Water.

[Evaluation of heat resistance]
Using an EXSTAR6000TG-DTA device manufactured by SII Nanotechnology Co., Ltd., put about 5 mg of a sample in a non-sealed aluminum container and heat it to 500 ° C. at a heating rate of 10 ° C./min in a nitrogen gas (100 ml / min) stream. The amount of heat weight loss was measured by this method. From a practical point of view, the following A or B evaluation is preferable. If it is evaluated as A or B, it has high heat resistance and can be applied to high temperature baking.
<Evaluation Criteria>
A: Thermal weight loss at 400°C is less than 10% B: Thermal weight loss at 400°C is 10% to 25%
C: Thermal weight loss at 400 ° C. is more than 25%

[Evaluation of solubility]
In a 50 ml screw bottle, propylene glycol monomethyl ether acetate (PGMEA) or cyclohexanone (CHN) as a solvent and a compound and/or resin are charged, and after stirring with a magnetic stirrer at 23 ° C. for 1 hour, the compound and / or resin is added. The amount dissolved in the solvent was measured, and the results were evaluated according to the following criteria. From a practical point of view, the following A or B evaluation is preferable. If it is evaluated as A or B, it has high storage stability in a solution state and can be sufficiently applied even in a semiconductor microfabrication process.
<Evaluation Criteria>
A: 10% by mass or more B: 5% by mass or more and less than 10% by mass C: less than 5% by mass

なお、４００ＭＨｚ－¹Ｈ－ＮＭＲにより以下のピークが見出され、上記式の化学構造を有することを確認した。
¹Ｈ－ＮＭＲ：（ｄ－ＤＭＳＯ、内部標準ＴＭＳ）
δ（ｐｐｍ）６．７～７．４（１２Ｈ，Ｐｈ－Ｈ）、６．４（４Ｈ，－ＣＨ＝ＣＨ－）、１．６～１．７（１２Ｈ，－Ｃ（ＣＨ３）２）。得られた化合物について、前記方法により分子量を測定した結果、５０４であった。 (Synthesis Example 1) Synthesis of BisAP maleimide A vessel with an inner volume of 100 ml equipped with a stirrer, a condenser and a burette was prepared. In this container, 4.61 g (10.0 mmol) of 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (product name: Bisaniline P, manufactured by Mitsui Chemicals Fine Co., Ltd.), maleic anhydride 2.15 g (22.0 mmol) of acid (manufactured by Kanto Kagaku Co., Ltd.), 40 ml of dimethylformamide and 30 ml of m-xylene were charged, and 0.4 g (2.3 mmol) of p-toluenesulfonic acid was added to the reaction mixture. prepared. This reaction mixture was stirred at 130° C. for 4.0 hours to carry out the reaction, and the water produced by azeotropic dehydration was recovered with a Dean-Stark trap. Next, after cooling the reaction liquid to 40° C., it was dropped into a beaker containing 300 ml of distilled water to precipitate a product. After filtering the resulting slurry solution, the residue was washed with methanol and separated and purified by column chromatography to obtain 2.4 g of the target compound (BisAP maleimide) represented by the following formula.

The following peaks were found by 400 MHz- ¹ H-NMR, confirming that the compound had the chemical structure of the above formula.
¹ H-NMR: (d-DMSO, internal standard TMS)
δ (ppm) 6.7-7.4 (12H, Ph-H), 6.4 (4H, -CH=CH-), 1.6-1.7 (12H, -C(CH3)2). As a result of measuring the molecular weight of the obtained compound by the method described above, it was 504.

なお、４００ＭＨｚ－¹Ｈ－ＮＭＲにより以下のピークが見出され、上記式の化学構造を有することを確認した。
¹Ｈ－ＮＭＲ：（ｄ－ＤＭＳＯ、内部標準ＴＭＳ）
δ（ｐｐｍ）６．８～７．５（１２Ｈ，Ｐｈ－Ｈ）、７．１（４Ｈ，－ＣＨ＝ＣＨ－）。得られた化合物について、前記方法により分子量を測定した結果、４５２であった。 (Synthesis Example 2) Synthesis of APB-N maleimide A container with an inner volume of 100 ml equipped with a stirrer, a condenser and a burette was prepared. In this container, 2.92 g (10.0 mmol) of 3,3′-(1,3-phenylenebis)oxydianiline (product name: APB-N, manufactured by Mitsui Chemicals Fine Co., Ltd.), maleic anhydride (Kanto Chemical Co., Ltd.) 2.15 g (22.0 mmol), dimethylformamide 30 ml and m-xylene 30 ml were charged, and p-toluenesulfonic acid 0.4 g (2.3 mmol) was added to prepare a reaction solution. This reaction mixture was stirred at 130° C. for 4.0 hours to carry out the reaction, and the water produced by azeotropic dehydration was recovered with a Dean-Stark trap. Next, after cooling the reaction liquid to 40° C., it was dropped into a beaker containing 300 ml of distilled water to precipitate a product. After filtering the resulting slurry solution, the residue was washed with methanol and separated and purified by column chromatography to obtain 1.84 g of the target compound (APB-N maleimide) represented by the following formula.

The following peaks were found by 400 MHz- ¹ H-NMR, confirming that the compound had the chemical structure of the above formula.
¹ H-NMR: (d-DMSO, internal standard TMS)
δ (ppm) 6.8-7.5 (12H, Ph—H), 7.1 (4H, —CH═CH—). As a result of measuring the molecular weight of the obtained compound by the method described above, it was 452.

なお、４００ＭＨｚ－¹Ｈ－ＮＭＲにより以下のピークが見出され、上記式の化学構造を有することを確認した。
¹Ｈ－ＮＭＲ：（ｄ－ＤＭＳＯ、内部標準ＴＭＳ）
δ（ｐｐｍ）６．６～７．４（１６Ｈ，Ｐｈ－Ｈ）、６．４（４Ｈ，－ＣＨ＝ＣＨ－）
得られた化合物について、前記方法により分子量を測定した結果、６７８であった。 (Synthesis Example 3) Synthesis of HFBAPP maleimide A container with an inner volume of 100 ml equipped with a stirrer, a condenser and a burette was prepared. This container was charged with 5.18 g (10.0 mmol) of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (product name: HFBAPP, manufactured by Wakayama Seika Kogyo Co., Ltd.), maleic anhydride. (manufactured by Kanto Kagaku Co., Ltd.) 2.15 g (22.0 mmol), 30 ml of dimethylformamide and 30 ml of m-xylene were charged, and 0.4 g (2.3 mmol) of p-toluenesulfonic acid was added to prepare a reaction solution. bottom. This reaction mixture was stirred at 130° C. for 5.0 hours to carry out the reaction, and the water produced by azeotropic dehydration was recovered with a Dean-Stark trap. Next, after cooling the reaction liquid to 40° C., it was dropped into a beaker containing 300 ml of distilled water to precipitate a product. After filtering the resulting slurry solution, the residue was washed with methanol and separated and purified by column chromatography to obtain 3.5 g of the target compound (HFBAPP maleimide) represented by the following formula.

The following peaks were found by 400 MHz- ¹ H-NMR, confirming that the compound had the chemical structure of the above formula.
¹ H-NMR: (d-DMSO, internal standard TMS)
δ (ppm) 6.6 ~ 7.4 (16H, Ph-H), 6.4 (4H, -CH=CH-)
As a result of measuring the molecular weight of the obtained compound by the method described above, it was 678.

前記方法により、上記ビスマレイミドの分子量を測定した結果、５７０であった。
熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、５質量％以上１０質量％未満（評価Ｂ）であり、得られたリソグラフィー用膜形成材料は十分な溶解性を有するものと評価されため、前記マレイミド化合物１０質量部に対し、溶媒としてＰＧＭＥＡを９０質量部加え、室温下、スターラーで少なくとも３時間以上攪拌させることにより、リソグラフィー用膜形成用組成物を調製した。 <Example 1>
As a maleimide compound, 10 parts by mass of bismaleimide represented by the following formula (BMI-80; manufactured by KAI Kasei Co., Ltd.) was used alone to prepare a lithographic film-forming material.

As a result of measuring the molecular weight of the bismaleimide by the above method, it was 570.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 5% by mass or more and less than 10% by mass (evaluation B), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. 90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 2>
As a maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 3>
As a maleimide compound, 10 parts by mass of the APB-N maleimide obtained in Synthesis Example 2 was used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 4>
As a maleimide compound, 10 parts by mass of HFBAPP maleimide obtained in Synthesis Example 3 was used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

前記方法により、上記マレイミドオリゴマーの平均分子量を測定した結果、８２０であった。
熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 5>
As a maleimide compound, 10 parts by mass of a phenylmethane maleimide oligomer (BMI oligomer; BMI-2300, manufactured by Daiwa Kasei Kogyo Co., Ltd.) represented by the following formula was used alone to prepare a film-forming material for lithography.

The average molecular weight of the maleimide oligomer measured by the above method was 820.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

前記方法により、上記マレイミドオリゴマーの平均分子量を測定した結果、９４３であった。
熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 6>
As a maleimide compound, 10 parts by mass of a biphenylaralkyl-type maleimide oligomer (MIR-3000-L, manufactured by Nippon Kayaku Co., Ltd.) represented by the following formula was used alone to prepare a film-forming material for lithography.

The average molecular weight of the maleimide oligomer measured by the above method was 943.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 7>
10 parts by mass of BMI-80 as a maleimide compound and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator were blended to prepare a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 5% by mass or more and less than 10% by mass (evaluation B), and the obtained film-forming material for lithography was evaluated to have sufficient solubility. A film-forming composition for lithography was prepared in the same manner as in Example 1.

<Example 8>
As a maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1, and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator are blended to form a film-forming material for lithography. and
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 9>
As a maleimide compound, 10 parts by mass of the APB-N maleimide obtained in Synthesis Example 2, and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator were blended to form a film for lithography. used as a forming material.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 10>
As a maleimide compound, 10 parts by mass of HFBAPP maleimide obtained in Synthesis Example 3 and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator are blended, and a film-forming material for lithography is prepared. and
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having sufficient solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 11>
As the maleimide compound, 10 parts by mass of the phenylmethane maleimide oligomer (BMI oligomer; BMI-2300, manufactured by Daiwa Kasei Kogyo Co., Ltd.) used in Example 5, and 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator. 0.1 part by mass was blended to obtain a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 12>
As the maleimide compound, 10 parts by mass of the biphenylaralkyl-type maleimide oligomer (MIR-3000-L, manufactured by Nippon Kayaku Co., Ltd.) used in Example 6, and as a crosslinking accelerator, 2,4,5-triphenylimidazole (TPIZ ) was blended to obtain a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in CHN, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 13>
10 parts by mass of BMI-80 was used as the maleimide compound. In addition, 2 parts by mass of benzoxazine (BF-BXZ; manufactured by Konishi Chemical Industry Co., Ltd.) represented by the following formula is used as a cross-linking agent, and 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. 0.1 part by mass was blended to obtain a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 14>
10 parts by mass of BMI-80 was used as the bismaleimide compound. Also, as a cross-linking agent, 2 parts by mass of a biphenyl aralkyl-type epoxy resin (NC-3000-L; manufactured by Nippon Kayaku Co., Ltd.) represented by the following formula is used, and 0.1 part by mass of TPIZ is added as a cross-linking accelerator. and used as a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 15>
10 parts by mass of BMI-80 was used as the maleimide compound. Further, as a cross-linking agent, 2 parts by mass of diallyl bisphenol A type cyanate (DABPA-CN; manufactured by Mitsubishi Gas Chemical Co., Ltd.) represented by the following formula is used, and 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. was blended in an amount of 0.1 part by mass to prepare a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 16>
10 parts by mass of BMI-80 was used as the maleimide compound. In addition, 2 parts by mass of diallyl bisphenol A (BPA-CA; manufactured by Konishi Kagaku Co., Ltd.) represented by the following formula was used as a cross-linking agent, and 0.5 parts of 2,4,5-triphenylimidazole (TPIZ) was used as a cross-linking accelerator. 1 part by mass was blended to obtain a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 17>
10 parts by mass of BMI-80 was used as the maleimide compound. Further, as a cross-linking agent, 2 parts by mass of a diphenylmethane-type allylphenol resin (APG-1; manufactured by Gunei Chemical Industry Co., Ltd.) represented by the following formula is used, and 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. ) was blended to obtain a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 18>
10 parts by mass of BMI-80 was used as the maleimide compound. Further, as a cross-linking agent, 2 parts by mass of a diphenylmethane-type propenylphenol resin (APG-2; manufactured by Gunei Chemical Industry Co., Ltd.) represented by the following formula is used, and 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. ) was blended to obtain a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

熱重量測定の結果、得られたリソグラフィー用膜形成材料の４００℃での熱重量減少量は１０％未満（評価Ａ）であった。また、ＰＧＭＥＡへの溶解性を評価した結果、１０質量％以上（評価Ａ）であり、得られたリソグラフィー用膜形成材料は優れた溶解性を有するものと評価されたため、前記実施例１と同様の操作にてリソグラフィー用膜形成用組成物を調製した。 <Example 19>
10 parts by mass of BMI-80 as a maleimide compound, 2 parts by mass of 4,4'-diaminodiphenylmethane (DDM; manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula as a cross-linking agent, and 2 parts by mass as a cross-linking accelerator. , 4,5-triphenylimidazole (TPIZ) was blended in an amount of 0.1 part by mass to prepare a film-forming material for lithography.

As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 20>
As the maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of benzoxazine (BF-BXZ; manufactured by Konishi Chemical Industry Co., Ltd.) is used as a cross-linking agent, and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) is added as a cross-linking accelerator. and used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 21>
As the bismaleimide compound, 10 parts by mass of BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of a biphenyl aralkyl epoxy resin (NC-3000-L; manufactured by Nippon Kayaku Co., Ltd.) was used as a cross-linking agent, and 0.1 part by mass of TPIZ was added as a cross-linking accelerator to form a film for lithography. material.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 22>
As the maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of diallyl bisphenol A type cyanate (DABPA-CN; manufactured by Mitsubishi Gas Chemical Co., Ltd.) is used as a cross-linking agent, and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. It was blended and used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 23>
As the maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of diallyl bisphenol A (BPA-CA; manufactured by Konishi Chemical Co., Ltd.) is used as a cross-linking agent, and 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) is added as a cross-linking accelerator. It was used as a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 24>
As the maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of diphenylmethane-type allylphenol resin (APG-1; manufactured by Gunei Chemical Industry Co., Ltd.) was used as a cross-linking agent, and 0.1 mass of 2,4,5-triphenylimidazole (TPIZ) was used as a cross-linking accelerator. The parts were blended to prepare a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 25>
As the maleimide compound, 10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used. In addition, 2 parts by mass of diphenylmethane-type propenylphenol resin (APG-2; manufactured by Gunei Chemical Industry Co., Ltd.) is used as a cross-linking agent, and 0.1 mass of 2,4,5-triphenylimidazole (TPIZ) is used as a cross-linking accelerator. The parts were blended to prepare a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 26>
10 parts by mass of the BisAP maleimide obtained in Synthesis Example 1 was used as the maleimide compound, and 2 parts by mass of 4,4'-diaminodiphenylmethane (DDM; manufactured by Tokyo Kasei) was used as the cross-linking accelerator. 0.1 part by mass of 2,4,5-triphenylimidazole (TPIZ) was added to prepare a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Comparative Example 1>
As a maleimide compound, 10 parts by mass of N,N'-biphenyl-based bismaleimide (BMI-70; manufactured by KAI Kasei Co., Ltd.) represented by the following formula, and 2,4,5-triphenylimidazole (TPIZ) as a cross-linking accelerator ) was blended to obtain a film-forming material for lithography. BMI-70 has a molecular weight of 443.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Comparative Example 2>
10 parts by mass of BMI-70 as the maleimide compound, 2 parts by mass of benzoxazine (BF-BXZ; manufactured by Konishi Kagaku Kogyo Co., Ltd.) as the cross-linking agent, and 2,4,5-tri- 0.1 part by mass of phenylimidazole (TPIZ) was added to prepare a film-forming material for lithography.
As a result of thermogravimetric measurement, the amount of thermal weight loss at 400° C. of the obtained film-forming material for lithography was less than 10% (Evaluation A). Further, as a result of evaluating the solubility in PGMEA, it was 10% by mass or more (evaluation A), and the obtained film-forming material for lithography was evaluated as having excellent solubility. A composition for forming a film for lithography was prepared by the operation of .

<Example 27>
10 parts by mass of BMI-80 was used as the maleimide compound. Further, 0.1 part by mass of IRGACURE 184 (manufactured by BASF) represented by the following formula was blended as a radical photopolymerization initiator to obtain a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 28>
10 parts by mass of BisAP maleimide was used as the maleimide compound. Further, 0.1 part by mass of Irgacure 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to prepare a film-forming material for lithography.
90 parts by mass of CHN as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 29>
As the maleimide compound, 10 parts by mass of APB-N maleimide was used. Further, 0.1 part by mass of Irgacure 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to prepare a film-forming material for lithography.
90 parts by mass of CHN as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 30>
10 parts by mass of HFBAPP maleimide was used as the maleimide compound. Further, 0.1 part by mass of Irgacure 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to prepare a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 31>
10 parts by mass of BMI-2300 was used as the maleimide compound. Further, 0.1 part by mass of Irgacure 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to prepare a film-forming material for lithography.
90 parts by mass of CHN as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 32>
10 parts by mass of MIR-3000-L was used as the maleimide compound. Further, 0.1 part by mass of IRGACURE 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to prepare a film-forming material for lithography.
90 parts by mass of CHN as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 33>
10 parts by mass of BMI-80 as a maleimide compound, 2 parts by mass of diallyl bisphenol A type cyanate (DABPA-CN; manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a cross-linking agent, and IRGACURE 184 as a photoradical polymerization initiator. (manufactured by BASF) was blended to prepare a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 34>
10 parts by mass of BMI-80 as a maleimide compound, 2 parts by mass of diallyl bisphenol A (BPA-CA; manufactured by Konishi Chemical Co., Ltd.) as a cross-linking agent, and Irgacure 184 (manufactured by BASF) as a photoradical polymerization initiator. 0.1 part by mass was blended to obtain a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography. .

<Example 35>
As a maleimide compound, 5 parts by mass of BMI-80, as a cross-linking agent, 2 parts by mass of a diphenylmethane type allylphenol resin (APG-1; manufactured by Gunei Chemical Industry Co., Ltd.), as a photoradical polymerization initiator, Irgacure 184 (manufactured by BASF) ) was blended to obtain a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Example 36>
As a maleimide compound, 5 parts by mass of BMI-80, as a cross-linking agent, 2 parts by mass of a diphenylmethane-type propenylphenol resin (APG-2; manufactured by Gunei Chemical Industry Co., Ltd.), as a photoradical polymerization initiator, Irgacure 184 (manufactured by BASF) ) was blended to obtain a film-forming material for lithography.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the maleimide compound, and the mixture was stirred at room temperature with a stirrer for at least 3 hours to prepare a film-forming composition for lithography.

<Examples 1 to 26, Comparative Examples 1 to 2>
Film-forming compositions for lithography corresponding to Examples 1-26 and Comparative Examples 1-2 were prepared using the film-forming materials for lithography obtained in Examples 1-26 so as to have the compositions shown in Table 1. were each prepared. Next, the film-forming compositions for lithography of Examples 1 to 26 and Comparative Examples 1 and 2 were spin-coated on a silicon substrate, and the film thickness after pre-baking at 150° C. for 60 seconds was measured as the initial film thickness. After that, it was cured and baked at 240° C. for 60 seconds, and the film thickness of the coating film was measured. The film thickness reduction rate (%) was calculated from the difference between the initial film thickness and the film thickness after curing and baking, and the sublimation resistance of each underlayer film was evaluated under the conditions shown below.
Thereafter, the silicon substrate was immersed in a mixed solvent of 70% PGMEA/30% PGME for 60 seconds, and after removing the adhering solvent with an aeroduster, the solvent was dried at 110.degree. The film thickness reduction rate (%) was calculated from the film thickness difference before and after immersion, and the curability of each underlayer film was evaluated under the conditions shown below.
After curing and baking at 240° C., the underlayer film was further post-baked at 400° C. for 120 seconds, and the film thickness reduction rate (%) was calculated from the film thickness difference before and after baking to evaluate the film heat resistance of each underlayer film. In addition, the embeddability into the stepped substrate and the flatness were evaluated under the following conditions.

<Examples 27 to 36>
Film-forming compositions for lithography corresponding to Examples 27 to 36 were prepared so as to have the compositions shown in Table 2. Next, the film-forming composition for lithography of Examples 27 to 36 was spin-coated on a silicon substrate, then baked at 150° C. for 60 seconds to remove the solvent from the coating film, and then subjected to integrated exposure with a high-pressure mercury lamp. After curing with an amount of 1500 mJ/cm ² and an irradiation time of 60 seconds, the film thickness of the coating film was measured. Thereafter, the silicon substrate was immersed in a mixed solvent of 70% PGMEA/30% PGME for 60 seconds, and after removing the adhering solvent with an aeroduster, the solvent was dried at 110.degree. The film thickness reduction rate (%) was calculated from the film thickness difference before and after the immersion, and the curability of each underlayer film was evaluated under the following conditions.
Further, the film was baked at 400° C. for 120 seconds, and the film thickness reduction rate (%) was calculated from the film thickness difference before and after baking to evaluate the film heat resistance of each underlayer film. In addition, the embeddability into the stepped substrate and the flatness were evaluated under the following conditions.

[Curability evaluation]
<Evaluation Criteria>
S: Film thickness reduction rate before and after solvent immersion ≤ 1%
A: Film thickness reduction rate before and after solvent immersion ≤ 5%
B: Film thickness reduction rate before and after solvent immersion ≤ 10%
C: Film thickness reduction rate before and after solvent immersion>10%

[Evaluation of film heat resistance]
<Evaluation Criteria>
S: Film thickness reduction rate before and after baking at 400°C ≤ 10%
A: Film thickness reduction rate before and after baking at 400°C ≤ 15%
B: Film thickness reduction rate before and after baking at 400°C ≤ 20%
C: film thickness reduction rate before and after baking at 400° C.>20%

[Evaluation of embeddability in stepped substrate]
The embeddability into the stepped substrate was evaluated by the following procedure.
The composition for forming an underlayer film for lithography was applied onto a 60 nm line-and-space SiO ₂ substrate having a film thickness of 80 nm, and baked at 240° C. for 60 seconds to form a 90 nm underlayer film. A cross section of the obtained film was cut out and observed with an electron microscope to evaluate embeddability into the stepped substrate.
<Evaluation Criteria>
A: The uneven part of the 60 nm line-and-space SiO ₂ substrate has no defects and is filled with the underlying film.
C: A 60 nm line-and-space SiO ₂ substrate has defects in the irregularities, and the lower layer film is not buried.

[Flatness evaluation]
The film _- forming composition obtained above was applied to a SiO2 stepped substrate in which trenches of 100 nm width, 150 nm pitch, and 150 nm depth (aspect ratio: 1.5) and trenches (open spaces) of 5 μm width and 180 nm depth were mixed. Each item was painted. After that, it was baked at 240° C. for 120 seconds in an air atmosphere to form a resist underlayer film having a thickness of 200 nm. The shape of this resist underlayer film was observed with a scanning electron microscope ("S-4800" by Hitachi High-Technologies Corporation), and the difference (ΔFT) between the maximum and minimum values of the thickness of the resist underlayer film on the trench or space. was measured.
<Evaluation Criteria>
S: ΔFT<10 nm (best flatness)
A: 10 nm ≤ ΔFT < 20 nm (good flatness)
B: 20 nm ≤ ΔFT < 40 nm (slightly good flatness)
C: 40 nm ≤ ΔFT (poor flatness)

<Example 37>
The composition for forming a film for lithography in Example 1 was coated on a 300 nm-thick SiO ₂ substrate and baked at 240° C. for 60 seconds and then at 400° C. for 120 seconds to form a 70 nm-thick underlayer film. bottom. An ArF resist solution was applied on the underlayer film and baked at 130° C. for 60 seconds to form a photoresist layer with a film thickness of 140 nm. The ArF resist solution was prepared by blending 5 parts by mass of the compound of the following formula (22), 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 2 parts by mass of tributylamine, and 92 parts by mass of PGMEA. I used what I did.
In addition, the compound of the following formula (22) was prepared as follows. That is, 4.15 g of 2-methyl-2-methacryloyloxyadamantane, 3.00 g of methacryloyloxy-γ-butyrolactone, 2.08 g of 3-hydroxy-1-adamantyl methacrylate, and 0.38 g of azobisisobutyronitrile were added to tetrahydrofuran. It was made to melt|dissolve in 80 mL and it was set as the reaction solution. This reaction solution was polymerized for 22 hours while maintaining the reaction temperature at 63° C. under a nitrogen atmosphere, and then added dropwise to 400 mL of n-hexane. The produced resin thus obtained was coagulated and purified, and the produced white powder was filtered and dried under reduced pressure at 40° C. overnight to obtain a compound represented by the following formula.

In the above formula (22), 40, 40 and 20 indicate the ratio of each structural unit and do not indicate a block copolymer.

Then, using an electron beam lithography system (Elionix; ELS-7500, 50 keV), the photoresist layer is exposed, baked (PEB) at 115 ° C. for 90 seconds, and 2.38% by mass of tetramethylammonium hydroxide ( A positive resist pattern was obtained by developing with an aqueous TMAH) solution for 60 seconds. Table 3 shows the evaluation results.

<Example 38>
A positive resist pattern was obtained in the same manner as in Example 37, except that the composition for forming an underlayer film for lithography in Example 2 was used instead of the composition for forming an underlayer film for lithography in Example 1. . Table 3 shows the evaluation results.

<Example 39>
A positive resist pattern was obtained in the same manner as in Example 37, except that the composition for forming an underlayer film for lithography in Example 3 was used instead of the composition for forming an underlayer film for lithography in Example 1. . Table 3 shows the evaluation results.

<Example 40>
A positive resist pattern was obtained in the same manner as in Example 37, except that the composition for forming an underlayer film for lithography in Example 4 was used instead of the composition for forming an underlayer film for lithography in Example 1. . Table 3 shows the evaluation results.

<Comparative Example 3>
A photoresist layer was formed directly on the SiO ₂ substrate in the same manner as in Example 37, except that no underlayer film was formed, to obtain a positive resist pattern. Table 3 shows the evaluation results.

[evaluation]
For each of Examples 37 to 40 and Comparative Example 3, the shapes of the obtained resist patterns of 55 nm L/S (1:1) and 80 nm L/S (1:1) were examined with an electron microscope manufactured by Hitachi, Ltd. ( S-4800) was used for observation. With respect to the shape of the resist pattern after development, a resist pattern with good rectangularity without pattern collapse was evaluated as good, and a non-perfect resist pattern was evaluated as unsatisfactory. Further, as a result of the observation, the minimum line width with good rectangularity without pattern collapse was used as an index for evaluation as resolution. Further, the sensitivity was defined as the minimum energy amount of electron beams capable of drawing a good pattern shape, and this was used as an index for evaluation.

As is clear from Table 3, Examples 37 to 40 using the film-forming composition for lithography of the present embodiment containing a maleimide compound were significantly superior in both resolution and sensitivity compared to Comparative Example 3. It was confirmed that Moreover, it was confirmed that the shape of the resist pattern after development had no pattern collapse and had good rectangularity. Furthermore, from the difference in resist pattern shape after development, it is shown that the underlayer films of Examples 37 to 40 obtained from the film-forming compositions for lithography of Examples 1 to 4 have good adhesion to the resist material. rice field.

The film-forming material for lithography of the present embodiment has excellent sublimation resistance during thin film formation, relatively high heat resistance, relatively high solvent solubility, and excellent embedding characteristics in stepped substrates and film flatness. Excellent, wet process is applicable. Therefore, a lithographic film-forming composition containing a lithographic film-forming material can be widely and effectively used in various applications requiring these properties. In particular, the present invention can be effectively used in the fields of underlayer films for lithography and underlayer films for multi-layer resists.

Claims (25)

A group of the following formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
A film-forming material for lithography, wherein the compound has a molecular weight of 450 or more,
The content of the compound in the material is 51 to 100% by mass,
The compound is represented by the following formula (1A), the following formula (2), or the following formula (3),

(In formula (1A),
Each X is independently a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -CO-, -C(CF ₃ ) ₂ -, -CONH- or -COO- ,
A is a single bond, an oxygen atom, or a divalent hydrocarbon group having 6 to 80 carbon atoms which may contain a heteroatom, wherein the hydrocarbon group contains an aromatic ring,
each R ₁ is independently a group having 0 to 30 carbon atoms which may contain a heteroatom;
Each m1 is independently an integer of 0 to 4. )

(In formula (2),
each R ₂ is independently a group having 0 to 10 carbon atoms which may contain a heteroatom;
m2 is each independently an integer of 0 to 3,
each m2' is independently an integer of 0 to 4,
n is an integer of 1-4. )

(In formula (3),
R ₃ and R ₄ are each independently a group having 0 to 10 carbon atoms which may contain a heteroatom,
m3 is each independently an integer of 0 to 4,
m4 is each independently an integer of 0 to 4,
n is an integer of 0-4. )
Film-forming materials for lithography. In the formula (1A), A is a single bond, an oxygen atom, or any of the following structures;

Y is a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -,

is
The film-forming material for lithography according to claim 1 . In formula (1A) above, each X is independently a single bond, —O—, —C(CH ₃ ) ₂ —, —CO—, or —COO—;
A is a single bond, an oxygen atom, or the following structure,

Y is -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ -
3. The film-forming material for lithography according to claim 1 or 2 . 4. The film-forming material for lithography according to any one of claims 1 to 3 , wherein the heteroatom is selected from the group consisting of oxygen, fluorine and silicon. 5. The film-forming material for lithography according to any one of claims 1 to 4 , further comprising a cross-linking agent. The cross-linking agent is at least one selected from the group consisting of phenol compounds, epoxy compounds, cyanate compounds, amino compounds, benzoxazine compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds and azide compounds. The film-forming material for lithography according to claim 5 . 7. The film-forming material for lithography according to claim 5 or 6 , wherein said cross-linking agent has at least one allyl group. The content ratio of the cross-linking agent is 0.1 to 100 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass, according to any one of claims 5 to 7 . Film-forming materials for lithography. 9. The film-forming material for lithography according to any one of claims 1 to 8 , further comprising a cross-linking accelerator. 10. The film-forming material for lithography according to claim 9 , wherein the cross-linking accelerator is at least one selected from the group consisting of amines, imidazoles, organic phosphines, and Lewis acids. The content ratio of the cross-linking accelerator is 0.1 to 5 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass, The lithography according to claim 9 or 10 . film-forming material. 12. The film-forming material for lithography according to any one of claims 1 to 11 , further comprising a radical polymerization initiator. 13. The film forming method for lithography according to claim 12 , wherein the radical polymerization initiator is at least one selected from the group consisting of ketone-based photopolymerization initiators, organic peroxide-based polymerization initiators and azo-based polymerization initiators. material. The content of the radical polymerization initiator is 0.05 to 25 parts by mass when the mass of the compound having the group of formula (1) is 100 parts by mass, The lithography according to claim 12 or 13 . film-forming material. A film-forming composition for lithography, comprising the film-forming material for lithography according to any one of claims 1 to 14 and a solvent. 16. The film-forming composition for lithography according to claim 15 , further comprising an acid generator. 17. The film-forming composition for lithography according to claim 15 , further comprising a base generator. 18. The composition for forming a film for lithography according to any one of claims 15 to 17 , wherein the film for lithography is an underlayer film for lithography. An underlayer film for lithography formed using a film-forming composition for lithography,
The film-forming composition for lithography contains a film-forming material for lithography and a solvent,
The film-forming material for lithography is a group represented by the following formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
An underlayer film for lithography, wherein the compound has a molecular weight of 450 or more. forming an underlayer film on a substrate using a film-forming composition for lithography;
a step of forming at least one layer of photoresist layer on the underlayer film; and a step of irradiating a predetermined region of the photoresist layer with radiation and developing;
A resist pattern forming method comprising
The film-forming composition for lithography contains a film-forming material for lithography and a solvent,
The film-forming material for lithography is a group represented by the following formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
A method for forming a resist pattern, wherein the compound has a molecular weight of 450 or more. forming an underlayer film on a substrate using a film-forming composition for lithography;
forming an intermediate layer film on the underlayer film using a resist intermediate layer film material containing silicon atoms;
forming at least one photoresist layer on the intermediate layer film;
a step of irradiating a predetermined region of the photoresist layer with radiation and developing to form a resist pattern;
etching the intermediate layer film using the resist pattern as a mask;
etching the underlayer film using the resulting intermediate layer film pattern as an etching mask;
forming a pattern on the substrate by etching the substrate using the obtained underlayer film pattern as an etching mask;
A pattern forming method comprising
The film-forming composition for lithography contains a film-forming material for lithography and a solvent,
The film-forming material for lithography is a group represented by the following formula (1):

(In formula (1),
Each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
containing a compound having
The pattern forming method, wherein the compound has a molecular weight of 450 or more. a step of dissolving the film-forming material for lithography according to any one of claims 1 to 14 in a solvent to obtain an organic phase;
a first extraction step of contacting the organic phase with an acidic aqueous solution to extract impurities in the film-forming material for lithography;
including
A purification method, wherein the solvent used in the step of obtaining the organic phase comprises a solvent optionally immiscible with water. The acidic aqueous solution is a mineral acid aqueous solution or an organic acid aqueous solution,
The mineral acid aqueous solution contains one or more selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid,
The organic acid aqueous solution is the group consisting of acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tartaric acid, citric acid, methanesulfonic acid, phenolsulfonic acid, p-toluenesulfonic acid and trifluoroacetic acid. 23. The purification method according to claim 22 , comprising one or more selected from. The water-immiscible solvent optionally is one or more solvents selected from the group consisting of toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, and ethyl acetate. The purification method according to 22 or 23. 25. The purification according to any one of claims 22 to 24 , further comprising, after said first extraction step, a second extraction step of contacting said organic phase with water to extract impurities in said film-forming material for lithography. Method.