JP2019200244A - Film-forming material for lithography, film-forming composition for lithography, underlay film for lithography and patterning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film forming material for lithography useful for forming a photoresist underlayer film which is applicable to a wet process and is excellent in heat resistance, etching resistance, burying property on a stepped substrate and film flatness. A film-forming material for lithography containing an oxazine compound. [Selection diagram] None

Description

  The present invention relates to a film forming material for lithography, a composition for forming a film for lithography containing the material, a lower layer film for lithography formed using the composition, and a pattern forming method using the composition (for example, a resist pattern). Method or circuit pattern method).

  In the manufacture of semiconductor devices, fine processing by lithography using a photoresist material is performed. In recent years, with the higher integration and higher speed of LSI, further miniaturization by a pattern rule is required. In lithography using light exposure, which is currently used as a general-purpose technology, the limit of the essential resolution derived from the wavelength of the light source is approaching.

  The light source for lithography used in forming the resist pattern is shortened from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). However, as the miniaturization of the resist pattern progresses, there arises a problem of resolution or a problem that the resist pattern collapses after development. Therefore, it is desired to reduce the thickness of the resist. However, simply thinning the resist makes it difficult to obtain a resist pattern film thickness sufficient for substrate processing. Therefore, not only a resist pattern but also a process in which a resist underlayer film is formed between the resist and a semiconductor substrate to be processed and the resist underlayer film also has a function as a mask during substrate processing has become necessary.

  Currently, various resist underlayer films for such processes are known. For example, unlike a conventional resist underlayer film having a high etching rate, a terminal layer is removed by applying a predetermined energy as a resist underlayer film for lithography having a dry etching rate selection ratio close to that of a resist. A material for forming an underlayer film for a multilayer resist process has been proposed, which contains at least a resin component having a substituent that generates a sulfonic acid residue and a solvent (see Patent Document 1). Also, 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 lower dry etching rate selectivity than that of a resist (see Patent Document 2). .) Furthermore, in order to realize a resist underlayer film for lithography having a low dry etching rate selection ratio compared with a semiconductor substrate, a repeating unit of acenaphthylenes and a repeating unit having a substituted or unsubstituted hydroxy group are copolymerized. A resist underlayer film material containing a polymer is proposed (see Patent Document 3).

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

  In addition, the inventors of the present invention provide a lithographic lower layer containing a naphthalene formaldehyde polymer containing a specific structural unit and an organic solvent as a material that is excellent in optical characteristics and etching resistance and is soluble in a solvent and applicable to a wet process. A film-forming composition (see Patent Documents 4 and 5) is proposed.

  As for a method for forming an intermediate layer used in forming a resist underlayer film in a three-layer process, for example, a silicon nitride film formation method (see Patent Document 6) or a silicon nitride film CVD method (Patent Document 7). See.) Is known. As an intermediate layer material for a three-layer process, a material containing a silsesquioxane-based silicon compound is known (see Patent Documents 8 and 9).

JP 2004-177668 A JP 2004-271838 A JP-A-2005-250434 International Publication No. 2009/072465 International Publication No. 2011/034062 JP 2002-334869 A International Publication No. 2004/066377 JP 2007-226170 A JP 2007-226204 A

  As described above, a large number of film forming materials for lithography have been proposed, but not only have high solvent solubility to which wet processes such as spin coating and screen printing can be applied, but also heat resistance, etching resistance, There is nothing that combines the characteristics of embedding in a stepped substrate and the flatness of a film at a high level, and the development of new materials is required.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to apply a wet process, and a photoresist underlayer excellent in heat resistance, etching resistance, step-filling characteristics and film flatness. To provide a film forming material for lithography useful for forming a film, a composition for forming a film for lithography containing the material, and a lower layer film for lithography and a pattern forming method using the composition .

［式中、
Ｒ^１及びＲ^２は、独立して、炭素数１〜３０の有機基であり、
Ｒ^３〜Ｒ^６は、独立して、水素又は炭素数１〜６の炭化水素基であり、
Ｘは、単結合、−Ｏ−、−Ｓ−、−Ｓ−Ｓ−、−ＳＯ₂−、−ＣＯ−、−ＣＯＮＨ−、−ＮＨＣＯ−、−Ｃ（ＣＨ₃）₂−、−Ｃ（ＣＦ₃）₂−、−（ＣＨ₂）_m−、−Ｏ−（ＣＨ₂）_m−Ｏ−、又は−Ｓ−（ＣＨ₂）_m−Ｓ−であり、
ｍは１〜６の整数であり、
Ｙは、独立して、単結合、−Ｏ−、−Ｓ−、−ＣＯ−、−Ｃ（ＣＨ₃）₂−、−Ｃ（ＣＦ₃）₂−、又は炭素数１〜３のアルキレンである］。
［４］
下記式（０）の基：

（式（０）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）
を有する化合物をさらに含有する、［１］〜［３］のいずれかに記載のリソグラフィー用膜形成材料。
［５］
架橋剤をさらに含有する、［１］〜［４］のいずれかに記載のリソグラフィー用膜形成材料。
［６］
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、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、［５］に記載のリソグラフィー用膜形成材料。
［７］
架橋促進剤をさらに含有する、［１］〜［６］のいずれか一項に記載のリソグラフィー用膜形成材料。
［８］
ラジカル重合開始剤をさらに含有する、［１］〜［７］のいずれか一項に記載のリソグラフィー用膜形成材料。
［９］
［１］〜［８］のいずれか一項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。
［１０］
酸発生剤をさらに含有する、［９］に記載のリソグラフィー用膜形成用組成物。
［１１］
リソグラフィー用膜がリソグラフィー用下層膜である、［１０］に記載のリソグラフィー用膜形成用組成物。
［１２］
［１１］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。
［１３］
基板上に、［１１］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。
［１４］
基板上に、［１１］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、及び
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、回路パターン形成方法。
［１５］
［１］〜［８］のいずれか一項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。 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.
[1]
A film forming material for lithography containing an oxazine compound.
[2]
The film formation for lithography according to [1], wherein the oxazine compound includes a condensed ring of a six-membered ring containing one oxygen atom, one nitrogen atom and four carbon atoms as ring member atoms, and an aromatic ring. material.
[3]
The film forming material for lithography according to [2], wherein the oxazine compound is at least one selected from the group consisting of compounds represented by the following formulas (a) to (f).

[Where:
R ¹ and R ² are independently an organic group having 1 to 30 carbon atoms,
R ^{3 to} R ⁶ are independently hydrogen or a hydrocarbon group having 1 to 6 carbon atoms,
X represents a single bond, —O—, —S—, —S—S—, —SO ₂ —, —CO—, —CONH—, —NHCO—, —C (CH ₃ ) ₂ —, —C (CF _{3) 2 -, - (CH} 2) m -, - O- (CH 2) m -O-, or -S- (CH ₂₎ a _m -S-,
m is an integer of 1-6,
Y is independently a single bond, —O—, —S—, —CO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or alkylene having 1 to 3 carbon atoms. ].
[4]
Group of the following formula (0):

(In formula (0), each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
The film forming material for lithography according to any one of [1] to [3], further comprising a compound having:
[5]
The film forming material for lithography according to any one of [1] to [4], further containing a crosslinking agent.
[6]
The cross-linking agent is at least one selected from the group consisting of phenol compounds, epoxy compounds, cyanate compounds, amino compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds and azide compounds, [5] The film forming material for lithography described in 1.
[7]
The film forming material for lithography according to any one of [1] to [6], further comprising a crosslinking accelerator.
[8]
The film forming material for lithography according to any one of [1] to [7], further comprising a radical polymerization initiator.
[9]
A composition for forming a film for lithography, comprising the film forming material for lithography according to any one of [1] to [8] and a solvent.
[10]
The film forming composition for lithography according to [9], further comprising an acid generator.
[11]
The composition for forming a film for lithography according to [10], wherein the film for lithography is an underlayer film for lithography.
[12]
A lower layer film for lithography formed by using the composition for forming a film for lithography according to [11].
[13]
Forming a lower layer film on the substrate using the composition for forming a film for lithography according to [11],
A step of forming at least one photoresist layer on the lower layer film; and a step of irradiating a predetermined region of the photoresist layer with radiation and developing
A resist pattern forming method.
[14]
Forming a lower layer film on the substrate using the composition for forming a film for lithography according to [11],
Forming an intermediate layer film on the lower layer film using a resist intermediate layer film material containing silicon atoms;
Forming at least one photoresist layer on the intermediate film;
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;
A step of etching the lower layer film using the obtained intermediate layer film pattern as an etching mask, and a step of forming a pattern on the substrate by etching the substrate using the obtained lower layer film pattern as an etching mask,
A circuit pattern forming method.
[15]
The step of dissolving the film forming material for lithography according to any one of [1] to [8] in a solvent to obtain an organic phase;
A first extraction step of bringing the organic phase into contact 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 includes a solvent that is not arbitrarily miscible with water.

  According to the present invention, a wet process is applicable, and a film forming material for lithography that is useful for forming a photoresist underlayer film that is excellent in heat resistance, etching resistance, step-filling characteristics and film flatness. A composition for forming a film for lithography containing the material, and a lower layer film for lithography and a pattern forming method using the composition can be provided.

  Embodiments of the present invention will be described below. In addition, the following embodiment is an illustration for demonstrating this invention, and this invention is not limited only to the embodiment.

[Film forming materials for lithography]
The film forming material for lithography which is one embodiment of the present invention contains an oxazine compound.

  From the viewpoint of heat resistance, the content of the oxazine compound in the film forming material for lithography of the present embodiment is preferably 5 to 100% by mass, more preferably 51 to 100% by mass, and 60 to More preferably, it is 100 mass%, More preferably, it is 70-100 mass%, It is especially preferable that it is 80-100 mass%.

  Although it does not specifically limit as an oxazine compound used for the film formation material for lithography of this embodiment, From a viewpoint of manufacture corresponding to raw material availability and mass production, one oxygen atom, one nitrogen atom, and It preferably contains a condensed ring of a 6-membered ring containing 4 carbon atoms and an aromatic ring. Here, an oxazine compound whose aromatic ring is a benzene ring is also called a benzoxazine compound, and an oxazine compound whose aromatic ring is a naphthalene ring is also called a naphthoxazine compound.

  As the oxazine compound, compounds represented by the following general formulas (a) to (f) are preferable from the viewpoint of etching resistance. In the following general formula, the bond displayed toward the center of the ring indicates that it is bonded to any carbon that forms the ring and can be bonded to a substituent.

In general formulas (a) to (f),
R ¹ and R ² are independently an organic group having 1 to 30 carbon atoms,
R ^{3 to} R ⁶ are independently hydrogen or a hydrocarbon group having 1 to 6 carbon atoms,
X represents a single bond, —O—, —S—, —S—S—, —SO ₂ —, —CO—, —CONH—, —NHCO—, —C (CH ₃ ) ₂ —, —C (CF _{3) 2 -, - (CH} 2) m -, - O- (CH 2) m -O-, or -S- (CH ₂₎ a _m -S-,
m is an integer of 1-6,
Y is independently a single bond, —O—, —S—, —CO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or alkylene having 1 to 3 carbon atoms. .

  The oxazine compound includes an oligomer or polymer having an oxazine structure in the side chain, and an oligomer or polymer having an oxazine structure in the main chain.

  The oxazine compound can be produced by the same method as described in International Publication No. 2004/009708, JP-A-11-12258, and JP-A-2004-352670.

  The film forming material for lithography of this embodiment can be applied to a wet process. In addition, the film forming material for lithography according to the present embodiment has an aromatic structure and a rigid oxazine skeleton, and even by itself, the oxazine skeleton undergoes a crosslinking reaction by high-temperature baking, resulting in high heat resistance. Expresses sex. As a result, deterioration of the film during high-temperature baking is suppressed, and a lower layer film having excellent etching resistance against oxygen plasma etching or the like can be formed. Furthermore, although the film forming material for lithography of this embodiment has an aromatic structure, it has high solubility in an organic solvent and high solubility in a safe solvent. Furthermore, the lower layer film for lithography composed of the composition for forming a film for lithography of the present embodiment to be described later is not only excellent in the embedding property to the stepped substrate and the flatness of the film, and the stability of the product quality is good. Since the adhesiveness to the layer and the resist intermediate layer film material is excellent, an excellent resist pattern can be obtained.

（式（０）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（以下、本明細書において「マレイミド化合物」ということがある。）をさらに含有することが好ましい。マレイミド化合物は、例えば、分子内に１個以上の第１級アミノ基を有する化合物と無水マレイン酸との脱水閉環反応により得ることができる。また、例えば、無水マレイン酸の代わりに無水シトラコン酸等を使用して同様にメチルマレイミド化されたもの等も含まれる。マレイミド化合物としては、例えば、ポリマレイミド化合物及びマレイミド樹脂を挙げることができる。
[Maleimide compound]
A film forming material for lithography that is one embodiment of the present invention is a group represented by the following formula (0):

(In formula (0), each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
It is preferable to further contain a compound having the following (hereinafter sometimes referred to as “maleimide compound” in the present specification). The maleimide compound can be obtained, for example, by a dehydration ring-closing reaction between a compound having one or more primary amino groups in the molecule and maleic anhydride. Further, for example, those obtained by methylmaleimidization using citraconic anhydride or the like instead of maleic anhydride are also included. Examples of maleimide compounds include polymaleimide compounds and maleimide resins.

  The content of the maleimide compound in the film forming material for lithography of the present embodiment is preferably 51 to 95% by mass, more preferably 60 to 95% by mass from the viewpoints of heat resistance and etching resistance. 70 to 95% by mass is more preferable, and 80 to 95% by mass is particularly preferable.

  As the polymaleimide compound and maleimide resin used for the film forming material for lithography of this embodiment, a bismaleimide compound and an addition polymerization type maleimide resin are preferable from the viewpoint of raw material availability and production corresponding to mass production.

式（１）中、Ｚはヘテロ原子を含んでいてもよい炭素数１〜１００の２価の炭化水素基である。炭化水素基の炭素数は、１〜８０、１〜６０、１〜４０、１〜２０等であってもよい。ヘテロ原子としては、酸素、窒素、硫黄、フッ素、ケイ素等を挙げることができる。 <Bismaleimide compound>
The bismaleimide compound is preferably a compound represented by the following formula (1).

In formula (1), Z is a C1-C100 bivalent hydrocarbon group which may contain a hetero atom. 1-80, 1-60, 1-40, 1-20 grade | etc., May be sufficient as carbon number of a hydrocarbon group. Examples of the hetero atom include oxygen, nitrogen, sulfur, fluorine, silicon and the like.

式（１Ａ）中、
Ｘはそれぞれ独立に、単結合、−Ｏ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−ＣＯ−、−Ｃ（ＣＦ_３）_２−、−ＣＯＮＨ−又は−ＣＯＯ−であり、
Ａは、単結合、酸素原子、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１〜８０の２価の炭化水素基であり、
Ｒ_１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 bismaleimide compound 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 C1-C80 bivalent hydrocarbon group which may contain a single bond, an oxygen atom, or a heteroatom (for example, oxygen, nitrogen, sulfur, fluorine),
Each R ₁ is independently a group having 0 to 30 carbon atoms which may contain a heteroatom (eg, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine);
m1 is an integer of 0-4 each independently.

Ｙは単結合、−Ｏ−、−ＣＨ_２−、−Ｃ（ＣＨ_３）_２−、−Ｃ（ＣＦ_３）_２−、

であり、
Ｒ_１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、
ｎは、０〜２０の整数であり、
ｍ１及びｍ２はそれぞれ独立に、０〜４の整数である。 More preferably, from the viewpoint of improving heat resistance and etching resistance, in the 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 represents a single bond, an oxygen _{atom, - (CH 2) n -} , - CH 2 C (CH 3) 2 CH 2 -, - (C (CH 3) 2) n -, - (O (CH 2) m2 ) _N −, — (O (C ₆ H ₄ )) _n −, or any of the following structures:

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

And
Each R ₁ is independently a group having 0 to 30 carbon atoms which may contain a heteroatom (eg, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine);
n is an integer of 0 to 20,
m1 and m2 are each independently an integer of 0 to 4.

X is preferably a single bond from the viewpoint of heat resistance, and is preferably —COO— from the viewpoint of solubility.
Y is preferably a single bond from the viewpoint of improving heat resistance.
R ₁ is preferably a group having 0 to 20 or 0 to 10 carbon atoms which may contain a hetero atom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine). R ₁ is preferably a hydrocarbon group from the viewpoint of improving solubility in an organic solvent. For example, examples of R ₁ include an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms), and specific examples include a methyl group and an ethyl group.
m1 is preferably an integer of 0 to 2, and is more preferably 1 or 2 from the viewpoint of improving raw material availability and solubility.
m2 is preferably an integer of 2 to 4.
n is preferably an integer of 0 to 2, and more preferably an integer of 1 to 2 from the viewpoint of improving heat resistance.

ｎ１は１〜１０の整数であり、
ｎ２は１〜４の整数であり、
ｎ３は１〜２０の整数であり、
Ｙは−Ｃ（ＣＨ_３）_２−又は−Ｃ（ＣＦ_３）_２−であり、
Ｒ_１はそれぞれ独立に、アルキル基（例えば、炭素数１〜６又は１〜３のアルキル基）であり、
ｍ１はそれぞれ独立に、０〜４の整数である。 As one embodiment of the compound represented by the formula (1A),
Each X is independently a single bond, —O—, —CO—, or —COO—;
A represents a single bond, an oxygen _{atom, - (CH 2) n1 -} , - CH 2 C (CH 3) 2 CH 2 -, - (O (CH 2) n2) n3 -, or following a structure,

n1 is an integer of 1 to 10,
n2 is an integer of 1 to 4,
n3 is an integer of 1 to 20,
Y is —C (CH ₃ ) ₂ — or —C (CF ₃ ) ₂ —,
Each R ₁ is independently an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms);
m1 is an integer of 0-4 each independently.

As one embodiment of the compound represented by the formula (1A),
X is a single bond,
A is — (CH ₂ ) _n1 —,
n1 is an integer of 1 to 10,
Each R ₁ is independently an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms);
m1 is an integer of 0-4 each independently.
Here, n1 is preferably 1 to 6 or 1 to 3.

As one embodiment of the compound represented by the formula (1A),
Each X is independently -CO- or -COO-;
A is — (O (CH ₂ ) _n2 ) _n3 —,
n2 is an integer of 1 to 4,
n3 is an integer of 1 to 20,
Each R ₁ is independently an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms);
m1 is an integer of 0-4 each independently.
Here, -X-A-X- is _{-CO- (O (CH 2) n2} ) n3 -COO- be preferable is.

であり、
Ｙは−Ｃ（ＣＨ_３）_２−又は−Ｃ（ＣＦ_３）_２−であり、
Ｒ_１はそれぞれ独立に、アルキル基（例えば、炭素数１〜６又は１〜３のアルキル基）であり、
ｍ１はそれぞれ独立に、０〜４の整数である。
ここで、Ａは以下の構造

であることが好ましい。 As one embodiment of the compound represented by the formula (1A),
X is —O—,
A is the following structure

And
Y is —C (CH ₃ ) ₂ — or —C (CF ₃ ) ₂ —,
Each R ₁ is independently an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms);
m1 is an integer of 0-4 each independently.
Where A is the following structure

It is preferable that

式（１Ｂ）中、Ｚ１はヘテロ原子を含んでいてもよい炭素数１〜１００の２価の直鎖状、分岐状、あるいは環状の炭化水素基である。ヘテロ原子としては、酸素、窒素、硫黄、フッ素、ケイ素等を挙げることができる。 The bismaleimide compound is preferably a compound represented by the following formula (1B).

In formula (1B), Z1 is a C1-C100 bivalent linear, branched or cyclic hydrocarbon group which may contain a hetero atom. Examples of the hetero atom include oxygen, nitrogen, sulfur, fluorine, silicon and the like.

<Addition polymerization type maleimide resin>
The addition polymerization maleimide resin is preferably a resin represented by the following formula (2) or the following formula (3) from the viewpoint of improving etching resistance.

In the formula (2), each R ₂ is independently a group having 0 to 10 carbon atoms which may contain a hetero atom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine). R ₂ is preferably a hydrocarbon group from the viewpoint of improving solubility in an organic solvent. For example, examples of R ₂ include an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms), and specific examples include a methyl group and an ethyl group.
m2 is an integer of 0-3 each independently. M2 is preferably 0 or 1, and more preferably 0 from the viewpoint of raw material availability.
m2 'is an integer of 0-4 each independently. M2 ′ is preferably 0 or 1, and more preferably 0 from the viewpoint of raw material availability.
n is an integer of 0-4. Further, 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 formula (3), R ₃ and R ₄ are each independently a group having 0 to 10 carbon atoms which may contain a hetero atom (for example, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine). is there. R ₃ and R ₄ are preferably hydrocarbon groups from the viewpoint of improving solubility in organic solvents. For example, examples of R ₃ and R ₄ include an alkyl group (for example, an alkyl group having 1 to 6 or 1 to 3 carbon atoms), and specific examples include a methyl group and an ethyl group.
m3 is an integer of 0-4 each independently. M3 is preferably an integer of 0 to 2, and more preferably 0 from the viewpoint of raw material availability.
m4 is each independently an integer of 0 to 4. M4 is preferably an integer of 0 to 2, and more preferably 0 from the viewpoint of raw material availability.
n is an integer of 0-4. Moreover, it is preferable that n is an integer of 1-4 or 0-2, and it is more preferable that it is an integer of 1-2 from a 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 according to the present embodiment has an aromatic structure and a rigid maleimide skeleton, and the maleimide group causes a crosslinking reaction by high-temperature baking alone, resulting in high heat resistance. Expresses sex. As a result, deterioration of the film during high-temperature baking is suppressed, and a lower layer film having excellent etching resistance against oxygen plasma etching or the like can be formed. Furthermore, although the film forming material for lithography of this embodiment has an aromatic structure, it has high solubility in an organic solvent and high solubility in a safe solvent. Furthermore, the lower layer film for lithography composed of the composition for forming a film for lithography of the present embodiment to be described later is not only excellent in the embedding property to the stepped substrate and the flatness of the film, and the stability of the product quality is good. Since the adhesiveness to the layer and the resist intermediate layer film material is also excellent, an excellent resist pattern can be obtained.

  Specific examples of the bismaleimide compound used in this embodiment include m-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4-diphenylmethane bismaleimide, and 4,4′-diphenyl sulfone. Bismaleimide, 1,3-bis (3-maleimidophenoxy) benzene, 1,3-bis (4-maleimidophenoxy) benzene, 1,4-bis (3-maleimidophenoxy) benzene, 1,4-bis (4- Phenylene skeleton-containing bismaleimide such as maleimidophenoxy) benzene; bis (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'-4,4 '-[3,3'-di-n-butyl-diphenylmethane] bismaleimide, etc. Diphenylalkane skeleton-containing bismaleimide, N, N′-4,4 ′-[3,3′-dimethyl-biphenylene] bismaleimide, N, N′-4,4 ′-[3,3′-diethyl-biphenylene] Bismaleimide containing biphenyl skeleton such as bismaleimide Aliphatic skeletons such as 1,6-hexane bismaleimide, 1,6-bismaleimide- (2,2,4-trimethyl) hexane, 1,3-dimethylenecyclohexane bismaleimide, 1,4-dimethylenecyclohexane bismaleimide Bismaleimide, 1,3-bis (3-aminopropyl) -1,1,2,2-tetramethyldisiloxane, 1,3-bis (3-aminobutyl) -1,1,2,2-tetra Methyldisiloxane, bis (4-aminophenoxy) dimethylsilane, 1,3-bis (4-aminophenoxy) tetramethyldisiloxane, 1,1,3,3-tetramethyl-1,3-bis (4-amino) Phenyl) disiloxane, 1,1,3,3-tetraphenoxy-1,3-bis (2-aminoethyl) disiloxane, 1,1,3,3-tetraphene 1,3-bis (2-aminoethyl) disiloxane, 1,1,3,3-tetraphenyl-1,3-bis (3-aminopropyl) disiloxane, 1,1,3,3-tetra Methyl-1,3-bis (2-aminoethyl) disiloxane, 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane, 1,1,3,3-tetra Methyl-1,3-bis (4-aminobutyl) disiloxane, 1,3-dimethyl-1,3-dimethoxy-1,3-bis (4-aminobutyl) disiloxane, 1,1,3,3 5,5-hexamethyl-1,5-bis (4-aminophenyl) trisiloxane, 1,1,5,5-tetraphenyl-3,3-dimethyl-1,5-bis (3-aminopropyl) trisiloxane 1,1,5,5-tetraphenyl-3 , 3-dimethoxy-1,5-bis (4-aminobutyl) trisiloxane, 1,1,5,5-tetraphenyl-3,3-dimethoxy-1,5-bis (5-aminopentyl) trisiloxane, 1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis (2-aminoethyl) trisiloxane, 1,1,5,5-tetramethyl-3,3-dimethoxy-1, 5-bis (4-aminobutyl) trisiloxane, 1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis (5-aminopentyl) trisiloxane, 1,1,3,3 , 5,5-hexamethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,3,3,5,5-hexaethyl-1,5-bis (3-aminopropyl) trisiloxane, , 1,3,3,5,5-he Sapuropiru 1,5-bis (3-aminopropyl) bismaleimide compound consisting diaminosiloxane trisiloxane such like.

  Among the bismaleimide compounds, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, N, N′-4,4 ′-[3,3′-dimethyl-diphenylmethane] bismaleimide, N, N ′ -4,4 '-[3,3'-diethyldiphenylmethane] bismaleimide is preferable because it is excellent in solvent solubility and heat resistance.

  Examples of the addition polymerization type maleimide resin used in this embodiment include bismaleimide M-20 (trade name, manufactured by Mitsui Toatsu Chemical Co., Ltd.), BMI-2300 (trade name, manufactured by Daiwa Kasei Kogyo Co., Ltd.), and BMI. -200 (manufactured by Daiwa Kasei Kogyo Co., Ltd., product name), MIR-3000 (manufactured by Nippon Kayaku Co., Ltd., product name) and the like. Among these, BMI-2300 is particularly preferable because of its excellent solubility and heat resistance.

<Crosslinking agent>
In addition to the oxazine compound, the film forming material for lithography of the present embodiment may further contain a crosslinking agent as necessary 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 the oxazine compound, and any known cross-linking system can be applied. Specific examples of the cross-linking agent that can be used in this embodiment include, for example, phenol compounds, epoxy compounds, Examples include cyanate compounds, amino compounds, acrylate compounds, melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, isocyanate compounds, azide compounds, and the like. These crosslinking agents can be used alone or in combination of two or more. Among these, an epoxy compound or a cyanate compound is preferable.

  In a crosslinking reaction between an oxazine compound and a crosslinking agent, for example, a phenol formed by opening an alicyclic portion of benzoxazine with an active group (phenolic hydroxyl group, epoxy group, cyanate group or amino group) possessed by these crosslinking agents. Reacts with functional hydroxyl groups.

  A well-known thing can be used as said phenolic compound. Examples of phenols include phenols, alkylphenols such as cresols and xylenols, polyhydric phenols such as hydroquinone, polycyclic phenols such as naphthols and naphthalenediols, and bisphenols such as bisphenol A and bisphenol F. Or polyfunctional phenol compounds such as phenol novolac and phenol aralkyl resin. Preferably, an aralkyl type phenol resin is desirable from the viewpoint of heat resistance and solubility.

  As the epoxy compound, known compounds can be used, and are selected from those having two or more epoxy groups in one molecule. For example, bisphenol A, bisphenol F, 3,3 ′, 5,5′-tetramethyl-bisphenol F, bisphenol S, fluorene bisphenol, 2,2′-biphenol, 3,3 ′, 5,5′-tetramethyl- Epoxidized dihydric phenols such as 4,4′-dihydroxybiphenol, resorcin, naphthalenediols, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane Tris (2,3-epoxypropyl) isocyanurate, trimethylol methane triglycidyl ether, trimethylol propane triglycidyl ether, triethylol ethane triglycidyl ether, phenol novolac, o-cresol novolac, etc. Epo Biphenyl synthesized from silicidates, epoxidized products of co-condensation resins of dicyclopentadiene and phenols, epoxidized products of phenol aralkyl resins synthesized from phenols and paraxylylene dichloride, etc., phenols and bischloromethylbiphenyl, etc. Examples thereof include epoxidized products of aralkyl type phenol resins, and epoxidized products of naphthol aralkyl resins synthesized from naphthols and paraxylylene dichloride. These epoxy resins may be used alone or in combination of two or more. From the viewpoint of heat resistance and solubility, an epoxy resin that is solid at room temperature such as an epoxy resin obtained from phenol aralkyl resins or biphenyl aralkyl resins is preferable.

  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. Examples thereof include those described in WO 2011108524. In this embodiment, preferred cyanate compounds are those having 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. Can be mentioned. Further, the cyanate compound preferably has an aromatic group, and a cyanate compound having a structure in which the cyanate group is directly connected to the aromatic group can be suitably used. Examples of such cyanate compounds include bisphenol A, bisphenol F, bisphenol M, bisphenol P, bisphenol E, phenol novolac resin, cresol novolac resin, dicyclopentadiene novolac resin, tetramethylbisphenol F, bisphenol A novolac resin, bromine. Bisphenol A, brominated phenol novolak resin, trifunctional phenol, tetrafunctional phenol, naphthalene type phenol, biphenyl type phenol, phenol aralkyl resin, biphenyl aralkyl resin, naphthol aralkyl resin, dicyclopentadiene aralkyl resin, alicyclic phenol, phosphorus The thing of the structure which substituted hydroxyl groups, such as containing phenol, by the cyanate group is mentioned. These cyanate compounds may be used alone or in combination of two or more. The cyanate compound described above may be in any form of a monomer, an oligomer, and a resin.

  Examples of the amino compound include m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3 , 3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl Sulfide, 3,3′-diaminodiphenyl sulfide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy ) Benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl ] Propane, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- ( 3-aminophenoxy) phenyl] ether, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-chlorophenyl) fluorene, 9,9-bis (4-amino-3- Fluorophenyl) fluorene, O-tolidine, m-tolidine, 4,4'-diaminobenzanilide, 2,2'-bis (trifluoromethyl) -4, '- diamino biphenyl, 4-aminophenyl-4-amino benzoate, 2- (4-aminophenyl) -6-amino-benzoxazole and the like. Among these, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4′- Diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) Benzene, 1,3-bis (3-aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2 -Bis [4- (3-aminophenoxy) phenyl] propane, 4,4′-bis (4-amino Aromatic amines such as phenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether Diaminocyclohexane, diaminodicyclohexylmethane, dimethyldiaminodicyclohexylmethane, tetramethyldiaminodicyclohexylmethane, diaminodicyclohexylpropane, diaminobicyclo [2.2.1] heptane, bis (aminomethyl) -bicyclo [2.2.1] heptane Alicyclic amines such as 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1.02,6] decane, 1,3-bisaminomethylcyclohexane, isophoronediamine, ethylenediamine , Hexamethylenediamy , Octamethylene diamine, decamethylene diamine, diethylene triamine, aliphatic amines such as triethylenetetramine, and the like.

  Specific examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl. Examples include a compound in which 1 to 6 methylol groups of melamine and hexamethylolmelamine are acyloxymethylated, or a mixture thereof.

  Specific examples of the guanamine compound include, for example, tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated, or a mixture thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine , A compound in which 1 to 4 methylol groups of tetramethylolguanamine are acyloxymethylated, or a mixture thereof.

  Specific examples of the glycoluril compound include, for example, tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril, a compound in which 1 to 4 methylol groups of tetramethylolglycoluril are methoxymethylated, or a mixture thereof, Examples thereof include compounds in which 1 to 4 methylol groups of tetramethylol glycoluril are acyloxymethylated, or mixtures thereof.

  Specific examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated, a mixture thereof, tetramethoxyethyl urea, and the like.

  Moreover, in this embodiment, you may use the crosslinking agent which has an at least 1 allyl group from a viewpoint of a crosslinking property improvement. Specific examples of the crosslinking agent having at least one allyl group include 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) ) Allylphenols such as ether, 2,2-bis (3-allyl-4-cyanatophenyl) propane, 1,1,1,3,3,3-hexafluoro-2,2-bis (3 -Allyl-4-cyanatophenyl) propane, bis (3-allyl-4-cyanatosiphenyl) sulfone, bis (3-allyl-4-cyanatophenyl) sulfide, bis (3- Examples include allyl cyanates such as (ryl-4-cyanatophenyl) ether, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl isocyanurate, trimethylolpropane diallyl ether, pentaerythritol allyl ether, and the like. It is not limited to what was done. These may be used alone or as a mixture of two or more. Among these, from the viewpoint of excellent compatibility with the bismaleimide compound and / or the addition polymerization type maleimide resin, 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, Allylphenols such as bis (3-allyl-4-hydroxyphenyl) ether are preferred.

  The film forming material for lithography according to the present embodiment can form the film for lithography according to the present embodiment by combining an oxazine compound alone or by blending the crosslinking agent, followed by crosslinking and curing by a known method. . Examples of the crosslinking method include methods such as thermosetting and photocuring.

  The content of the crosslinking agent is, for example, in the range of 0.1 to 100 parts by mass when the oxazine compound is 100 parts by mass, preferably 1 to 50 parts by mass from the viewpoint of heat resistance and solubility. It is a range, More preferably, it is the range of 1-30 mass parts.

  In the film forming material for lithography of the present embodiment, a crosslinking accelerator for accelerating the crosslinking and curing reaction can be used as necessary.

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

Examples of the crosslinking accelerator include, but are not limited to, for example, 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylamino). Tertiary amines such as methyl) phenol, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, 2,4,5- Imidazoles such as triphenylimidazole, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, tetraphenylphosphonium tetraphenylborate, tetrapheny Tetrasubstituted boron such as phosphonium / ethyltriphenylborate, tetrabutylphosphonium / tetrabutylborate, tetraphenylboron such as 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / tetraphenylborate Examples include salts.
As a compounding quantity of a crosslinking accelerator, when an oxazine compound is 100 mass parts normally, Preferably it is the range of 0.1-10 mass parts, More preferably, it is a viewpoint of ease of control and economical efficiency. From 0.1 to 5 parts by mass, more preferably from 0.1 to 3 parts by mass.

<Radical polymerization initiator>
A radical polymerization initiator can be blended in the film forming material for lithography of the present embodiment as necessary. 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.

  Such radical polymerization initiator is not particularly limited, and those conventionally used can be appropriately employed. For example, 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2 -Methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methylpropan-1-one, 2 , 4,6-trimethylbenzoyl-diphenyl-phosphine oxide, ketone photopolymerization initiators such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide Oxide, methyl acetoacetate Oxide, acetyl acetate peroxide, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis ( t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, 1 , 1-bis (t-butylperoxy) cyclododecane, 1,1-bis (t-butylperoxy) butane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, p -Mentane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutylhydride Peroxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2 , 5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, Isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoylbenzoyl peroxide, benzoyl peroxide, di-n -Propylpa Oxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3- Methoxybutyl peroxydicarbonate, di-s-butylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, kumi Luperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-Butylperoxyneodeca Ate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2- Ethyl hexanoate, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate, t-butyl peroxymalate, t-butyl peroxy-3,5,5-trimethylhexanoate, t -Butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t- Butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxyacetate, t-butyl peroxy-m-toluyl benzoate, t-butyl peroxybenzoate, bis (t-butylperoxy) isophthalate, 2,5- Dimethyl-2,5-bis (m-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, Organic peroxide polymerization initiators such as t-butyltrimethylsilyl peroxide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,3-dimethyl-2,3-diphenylbutane Is mentioned.

  2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1-[(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis ( 2-methylpropionamidine) dihydrochloride, 2,2′-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2′-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] Dihydride chloride, 2,2′-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride 2,2′-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride, 2,2′-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2, 2′-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepine) -2-yl) propane] dihydrochloride, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] Dihydrochloride, 2,2′-azobis [2- (5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- [1- ( 2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis [2-methyl -N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide ], 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2 ' Azobis (2,4,4-trimethylpentane), 2,2'-azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4- Also included are azo polymerization initiators such as cyanopentanoic acid) and 2,2′-azobis [2- (hydroxymethyl) propionitrile]. As the radical polymerization initiator in the present embodiment, one of these may be used alone, or two or more may be used in combination, or other known polymerization initiators may be used in further combination.

  The content of the radical polymerization initiator may be an amount stoichiometrically required with respect to the mass of the oxazine compound, but 0.05 to 25 mass when the oxazine compound is 100 mass parts. Part is preferable, and 0.1 to 10 parts by mass is more preferable. When the content of the radical polymerization initiator is 0.05 parts by mass or more, there is a tendency that the curing of the oxazine compound can be prevented from becoming insufficient, while the content of the radical polymerization initiator is 25. When the amount is less than or equal to part by mass, the long-term storage stability of the film forming material for lithography at room temperature tends to be prevented from being impaired.

[Purification method of film forming material for lithography]
The film forming material for lithography can be purified by washing with an acidic aqueous solution. In the purification method, a film forming material for lithography is dissolved in an organic solvent which is not arbitrarily miscible with water to obtain an organic phase, and the organic phase is contacted with an acidic aqueous solution to perform an extraction process (first extraction step). And a step of separating the organic phase from the aqueous phase after the metal component contained in the organic phase containing the film forming material for lithography and the organic solvent is transferred to the aqueous phase. By this purification, the content of various metals in the film forming material for lithography of the present invention can be significantly reduced.

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

  Specific examples of the organic solvent used include those described in International Publication No. 2015/080240. Among these, toluene, 2-heptanone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethyl acetate and the like are preferable, and cyclohexanone and propylene glycol monomethyl ether acetate are particularly preferable. 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. For example, the thing of international publication 2015/080240 is mentioned. These acidic aqueous solutions can be used alone or in combination of two or more. Examples of the acidic aqueous solution include a mineral acid aqueous solution and an organic acid aqueous solution. Examples of the mineral acid aqueous solution include an aqueous solution containing at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. Examples of the organic acid aqueous solution include acetic acid, propionic acid, succinic 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, and carboxylic acid such as acetic acid, succinic acid, tartaric acid, and citric acid, more preferably an aqueous solution of sulfuric acid, succinic acid, tartaric acid, and citric acid, and particularly an aqueous solution of succinic acid. preferable. Since polyvalent carboxylic acids such as succinic acid, tartaric acid, and citric acid are coordinated to metal ions to produce a chelate effect, it is considered that the metal can be removed more. Moreover, the water used here is preferably one having a low metal content, such as ion-exchanged water, for the purpose of the present invention.

  The pH of the acidic aqueous solution is not particularly limited, but if the acidity of the aqueous solution becomes too large, it may adversely affect the compound or resin used, which is not preferable. Usually, the pH range is about 0 to 5, more preferably about pH 0 to 3.

  The amount of the acidic aqueous solution used is not particularly limited. However, if the amount is too small, it is necessary to increase the number of extractions for removing the metal. Conversely, if the amount of the aqueous solution is too large, the total amount of the liquid increases. The above problems may occur. The usage-amount of aqueous solution is 10-200 mass parts normally with respect to the solution of the film forming material for lithography, Preferably it is 20-100 mass parts.

  The metal component can be extracted by bringing the acidic aqueous solution into contact with the film forming material for lithography and the solution (B) containing an organic solvent which is not arbitrarily miscible with water.

  The temperature at the time of performing the extraction treatment is usually 20 to 90 ° C, preferably 30 to 80 ° C. The extraction operation is performed, for example, by mixing the mixture well by stirring or the like and then allowing it to stand. Thereby, the metal component contained in the solution containing the compound to be used and the organic solvent moves to the aqueous phase. Moreover, the acidity of a solution falls by this operation, and the quality change of this compound to be used can be suppressed.

  After the extraction treatment, the solution is separated into a solution phase containing the compound to be used and an organic solvent and an aqueous phase, and a solution containing the organic solvent is recovered by decantation or the like. The standing time is not particularly limited. However, if the standing time is too short, the separation between the solution phase containing the organic solvent and the aqueous phase is not preferable. Usually, the time to stand still is 1 minute or more, More preferably, it is 10 minutes or more, More preferably, it is 30 minutes or more. The extraction process may be performed only once, but it is also effective to repeat the operations of mixing, standing, and separation a plurality of times.

  When such an extraction process is performed using an acidic aqueous solution, the organic phase containing the recovered organic solvent extracted from the aqueous solution after the process is further extracted with water (second extraction). It is preferable to carry out (step). The extraction operation is performed by allowing the mixture to stand after mixing well by stirring or the like. And since the obtained solution isolate | separates into the solution phase containing a compound and an organic solvent, and an aqueous phase, a solution phase is collect | recovered by decantation etc. Moreover, the water used here is preferably one having a low metal content, such as ion-exchanged water, for the purpose 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 separation a plurality of times. In addition, the use ratio of both in the extraction process, conditions such as temperature and time are not particularly limited, but may be the same as in the case of the contact process with the acidic aqueous solution.

  The moisture mixed in the solution containing the film forming material for lithography and the organic solvent thus obtained can be easily removed by performing an operation such as vacuum distillation. If necessary, an organic solvent can be added to adjust the concentration of the compound to an arbitrary concentration.

  A method for obtaining only the film forming material for lithography from the obtained solution containing an organic solvent can be performed by a known method such as removal under reduced pressure, separation by reprecipitation, and a combination thereof. If necessary, known processes such as a concentration operation, a filtration operation, a centrifugal separation operation, and a drying operation can be performed.

[Composition for forming a film for lithography]
The composition for film formation for lithography of this embodiment contains the said film formation material for lithography and a solvent. The lithography film is, for example, a lithography lower layer film.

  The composition for forming a film for lithography of the present embodiment may be applied to a substrate, then heated as necessary to evaporate the solvent, and then heated or irradiated to form a desired cured film. it can. The method for applying the composition for forming a film for lithography of the present embodiment is arbitrary, for example, spin coating method, dipping method, flow coating method, ink jet method, spray method, bar coating method, gravure coating method, slit coating method, A roll coating method, a transfer printing method, a brush coating method, a blade coating method, an air knife coating method, or the like can be appropriately employed.

  The heating temperature of the film is not particularly limited for the purpose of evaporating the solvent, and can be performed at 40 to 400 ° C., for example. The heating method is not particularly limited, and for example, it may be evaporated using a hot plate or an oven in an appropriate atmosphere such as air, an inert gas such as nitrogen, or in a vacuum. The heating temperature and the heating time may be selected under conditions suitable for the process steps of the target electronic device, and the heating conditions may be selected such that the physical properties of the obtained film meet the required characteristics of the electronic device. The conditions for light irradiation are not particularly limited, and an appropriate irradiation energy and irradiation time may be employed depending on the lithography film forming material to be used.

<Solvent>
The solvent used in the composition for forming a film for lithography of the present embodiment is not particularly limited as long as it can dissolve at least the oxazine 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 alone or in combination of two or more.

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

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

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

  Examples of the acid generator include those described in International Publication No. 2013/024779. Among these, in particular, triphenylsulfonium trifluoromethanesulfonate, trifluoromethanesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, trifluoromethanesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, p-toluenesulfonic acid Triphenylsulfonium, p-toluenesulfonic acid (p-tert-butoxyphenyl) diphenylsulfonium, p-toluenesulfonic acid tris (p-tert-butoxyphenyl) sulfonium, trifluoromethanesulfonic acid trinaphthylsulfonium, trifluoromethanesulfonic acid cyclohexylmethyl (2-oxocyclohexyl) sulfonium, trifluoromethanesulfonic acid (2-norbornyl) methyl (2-oxocyclohexyl) Sil) sulfonium, onium salts such as 1,2'-naphthylcarbonylmethyltetrahydrothiophenium triflate; bis (benzenesulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (n- Diazomethane derivatives such as butylsulfonyl) diazomethane, bis (isobutylsulfonyl) diazomethane, bis (sec-butylsulfonyl) diazomethane, bis (n-propylsulfonyl) diazomethane, bis (isopropylsulfonyl) diazomethane, bis (tert-butylsulfonyl) diazomethane; Glyoxime derivatives such as bis- (p-toluenesulfonyl) -α-dimethylglyoxime, bis- (n-butanesulfonyl) -α-dimethylglyoxime, Bissulfone derivatives such as naphthylsulfonylmethane; N-hydroxysuccinimide methanesulfonate, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide 1-propanesulfonate, N-hydroxysuccinimide 2-propanesulfonate, N-hydroxysuccinimide 1-pentanesulfonic acid ester, N-hydroxysuccinimide p-toluenesulfonic acid ester, N-hydroxynaphthalimide methanesulfonic acid ester, N-hydroxynaphthalimide benzenesulfonic acid ester, etc. Acid ester derivatives and the like are preferably used.

  In the composition for forming a film for lithography of the present embodiment, the content of the acid generator is not particularly limited, but is 0 to 50 parts by mass when the oxazine compound in the film forming material for lithography is 100 parts by mass. It is preferable that it is 0 to 40 parts by mass. By setting it as the above-mentioned preferable range, it exists in the tendency for a crosslinking reaction to be improved and it exists in the tendency for generation | occurrence | production of the mixing phenomenon with a resist layer to be suppressed.

<Basic compound>
Furthermore, the composition for forming a lower layer 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 acid generated in a trace amount from the acid generator from causing the crosslinking reaction to proceed. Examples of such basic compounds include, but are not limited to, primary, secondary or tertiary aliphatic amines, hybrid amines, aromatics described in International Publication No. 2013-024779, for example. 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 Examples thereof include imide derivatives.

  In the composition for forming a film for lithography of the present embodiment, the content of the basic compound is not particularly limited, but is 0 to 2 parts by mass when the oxazine compound in the film forming material for lithography is 100 parts by mass. It is preferable that it is 0 to 1 part by mass. By making it into the above preferable range, the storage stability tends to be enhanced without excessively impairing the crosslinking reaction.

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

[Liquid lower layer film and pattern forming method]
The underlayer film for lithography of this embodiment is formed using the composition for forming a film for lithography of this embodiment.

  Moreover, the pattern formation method of this embodiment is a process (A-1) which forms a lower layer film | membrane using the film | membrane formation composition for lithography of this embodiment on a board | substrate, and at least 1 on the said lower layer film | membrane. A step (A-2) of forming a photoresist layer as a layer, and a step (A-3) of performing development by irradiating a predetermined region of the photoresist layer with radiation after the step (A-2). Have.

  Furthermore, another pattern forming method of this embodiment includes a step (B-1) of forming a lower layer film on the substrate using the film forming composition for lithography of the present embodiment, and on the lower layer film, A step of forming an intermediate layer film using a resist intermediate layer film material containing silicon atoms (B-2), and a step of forming at least one photoresist layer on the intermediate layer film (B-3) After the step (B-3), a step (B-4) in which a predetermined region of the photoresist layer is irradiated with radiation and developed to form a resist pattern, and the step (B-4) Then, 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. Having a step (B-5) to form a pattern on a substrate with a.

  If the lower layer film for lithography of this embodiment is formed from the composition for film formation for lithography of this embodiment, the formation method will not be specifically limited, A well-known method can be applied. For example, after applying the film forming composition for lithography of the present embodiment on a substrate by a known coating method such as spin coating or screen printing or a printing method, the organic solvent is volatilized and removed, An underlayer film can be formed.

  At the time of forming the lower layer film, baking is preferably performed in order to suppress the occurrence of the mixing phenomenon with the upper layer resist and to promote the crosslinking reaction. In this case, the baking temperature is not particularly limited, but is preferably in the range of 80 to 450 ° C, more preferably 200 to 400 ° C. Further, the baking time is not particularly limited, but is preferably within a range of 10 to 300 seconds. The thickness of the lower layer film can be appropriately selected according to the required performance and is not particularly limited, but is usually preferably 30 to 20,000 nm, more preferably 50 to 15,000 nm, More preferably, it is 50-1000 nm.

  After forming the lower layer film on the substrate, in the case of a two-layer process, a silicon-containing resist layer thereon, or a single-layer resist made of ordinary hydrocarbon, in the case of a three-layer process, a silicon-containing intermediate layer thereon, It is preferable to form a single layer resist layer not containing silicon thereon. In this case, a well-known thing can be used as a photoresist material 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, If necessary, a positive photoresist material containing a basic compound or the like 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. By giving the intermediate layer an effect as an antireflection film, reflection tends to be effectively suppressed. For example, in a 193 nm exposure process, if a material containing many aromatic groups and high substrate etching resistance is used as the lower layer film, the k value increases and the substrate reflection tends to increase, but the reflection is suppressed in the intermediate layer. Thus, the substrate reflection can be reduced to 0.5% or less. The intermediate layer having such an antireflection effect is not limited to the following, but for 193 nm exposure, a polysilsesquioxy crosslinked with an acid or heat into which a light absorbing group having a phenyl group or a silicon-silicon bond is introduced. Sun is preferably used.

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

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

  In the case of forming a resist layer from the photoresist material, a wet process such as spin coating or screen printing is preferably used as in the case of forming the lower layer film. Further, after the resist material is applied by spin coating or the like, prebaking is usually performed, but this prebaking is preferably performed at 80 to 180 ° C. for 10 to 300 seconds. Then, according to a conventional method, a resist pattern can be obtained by performing exposure, post-exposure baking (PEB), and development. The thickness of the resist film is not particularly limited, but generally 30 to 500 nm is preferable, and 50 to 400 nm is more preferable.

  The exposure light may be appropriately selected and used depending on the photoresist material to be used. In general, high energy rays having 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 mentioned.

  The resist pattern formed by the above-described method is one in which pattern collapse is suppressed by the lower layer film of this embodiment. Therefore, by using the lower layer film of this embodiment, a finer pattern can be obtained, and the exposure amount necessary 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 as the etching of the lower layer film in the two-layer process. As gas etching, etching using oxygen gas is suitable. In addition to oxygen gas, it is also possible to add an inert gas such as He or Ar, or CO, CO ₂ , NH ₃ , SO ₂ , N ₂ , NO _{2, or} H ₂ gas. Further, gas etching can be performed only with CO, CO ₂ , NH ₃ , N ₂ , NO _{2, and} H ₂ gas without using oxygen gas. In particular, the latter gas is preferably used for side wall protection for preventing undercut of the pattern side wall.

  On the other hand, gas etching is also preferably used in the etching of the intermediate layer in the three-layer process. As the gas etching, the same gas etching as described in the above two-layer process can be applied. In particular, the processing of the intermediate layer in the three-layer process is preferably performed using a fluorocarbon gas and a resist pattern as a mask. Thereafter, as described above, the lower layer film can be processed by, for example, oxygen gas etching using the intermediate layer pattern as a mask.

  Here, when an inorganic hard mask intermediate layer film is formed as an intermediate layer, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) is formed by CVD or ALD. The method for forming the nitride film is not limited to the following, but for example, a method described in Japanese Patent Application Laid-Open No. 2002-334869 (Patent Document 6) and WO 2004/066377 (Patent Document 7) can be used. A photoresist film can be formed directly on such an intermediate film, but an organic antireflection film (BARC) is formed on the intermediate film by spin coating, and a photoresist film is formed thereon. May be.

  As the intermediate layer, a polysilsesquioxane-based intermediate layer is also preferably used. By providing the resist intermediate layer film with an effect as an antireflection film, reflection tends to be effectively suppressed. Specific materials of the polysilsesquioxane-based intermediate layer are not limited to the following, but are described, for example, in 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 performed by a conventional method. For example, if the substrate is SiO ₂ or SiN, etching mainly using a chlorofluorocarbon gas, if p-Si, Al, or W is chlorine or bromine, Etching mainly with gas can be performed. When the substrate is etched with a chlorofluorocarbon gas, the silicon-containing resist of the two-layer resist process and the silicon-containing intermediate layer of the three-layer process are peeled off simultaneously with the substrate processing. 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 separately peeled, and generally, dry etching peeling with a chlorofluorocarbon-based gas is performed after the substrate is processed. .

The lower layer film of this embodiment is characterized by excellent etching resistance of these substrates. The substrate may be appropriately selected and used those known, but are not limited to, include _{Si, α-Si, p-} Si, SiO 2, SiN, SiON, W, TiN, Al and the like . The substrate may be a laminate having a film to be processed (substrate to be processed) on a base material (support). Such film to be _{processed, Si, SiO 2, SiON,} SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al-Si , etc. Various Low-k film and stopper film In general, a material different from the base material (support) is used. The thickness of the substrate to be processed or the film to be processed is not particularly limited, but is usually preferably about 50 to 1,000,000 nm, more preferably 75 to 500,000 nm.

  EXAMPLES Hereinafter, although an Example, a manufacture example, and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

[Molecular weight]
The molecular weight of the synthesized compound was measured by LC-MS analysis using Water's Acquity UPLC / MALDI-Synapt HDMS.

[Evaluation of heat resistance]
Using an EXSTAR6000TG-DTA apparatus manufactured by SII NanoTechnology, about 5 mg of a sample is put in an aluminum non-sealed container, and the temperature is raised to 500 ° C. at a rate of temperature increase of 10 ° C./min in a nitrogen gas (100 ml / min) stream. The amount of thermal weight loss was measured. From the practical viewpoint, the following A or B evaluation is preferable. If it is A or B evaluation, 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 exceeds 25%

[Evaluation of solubility]
A 50 ml screw bottle is charged with propylene glycol monomethyl ether acetate (PGMEA) and a compound and / or resin, and after stirring for 1 hour with a magnetic stirrer at 23 ° C., the amount of the compound and / or resin dissolved in PGMEA is measured. The results were evaluated according to the following criteria. From the practical viewpoint, the following A or B evaluation is preferable. If it is A or B evaluation, it has high storage stability in a solution state and can be sufficiently applied to an edge beat rinse liquid (PGME / PGMEA mixed liquid) widely used 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

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。
前記リソグラフィー用膜形成材料中のビスマレイミド化合物と付加重合型マレイミド樹脂との合計質量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>
5 parts by mass of BMI-70 was used as the bismaleimide compound, and 5 parts by mass of BMI-2300 was used as the addition polymerization type maleimide resin. Further, 2 parts by mass of benzoxazine (BF-BXZ; manufactured by Konishi Chemical Industry Co., Ltd.) represented by the following formula is used, and 0.1 mass of 2,4,5-triphenylimidazole (TPIZ) is used as a crosslinking accelerator. Partly blended to form a film forming material for lithography.

As a result of thermogravimetry, the thermogravimetric decrease at 400 ° C. of the obtained film forming material for lithography was less than 10% (Evaluation A). Moreover, as a result of evaluating the solubility in PGMEA, it was 10 mass% or more (evaluation A), and the obtained film forming material for lithography was evaluated as having excellent solubility.
By adding 90 parts by mass of PGMEA as a solvent to the total mass of 10 parts by mass of the bismaleimide compound and the addition polymerization type maleimide resin in the film forming material for lithography, by stirring at least 3 hours or more at room temperature with a stirrer, A film forming composition for lithography was prepared.

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。
前記ビスマレイミド化合物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 2>
10 parts by mass of BMI-1000P as a bismaleimide compound, 2 parts by mass of benzoxazine BF-BXZ represented by the above formula, 0.1 parts by mass of TPIZ as a crosslinking accelerator are blended, and a film for lithography A forming material was obtained.

As a result of thermogravimetry, the thermogravimetric decrease at 400 ° C. of the obtained film forming material for lithography was less than 10% (Evaluation A). Moreover, as a result of evaluating the solubility in PGMEA, it was 10 mass% or more (evaluation A), and the obtained film forming material for lithography was evaluated as having excellent solubility.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the bismaleimide compound and stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

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。
前記ビスマレイミド化合物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 3>
10 parts by mass of BMI-80 as a bismaleimide compound, 2 parts by mass of benzoxazine BF-BXZ represented by the above formula, 0.1 parts by mass of TPIZ as a crosslinking accelerator are blended, and a film for lithography A forming material was obtained.

As a result of thermogravimetry, the thermogravimetric decrease at 400 ° C. of the obtained film forming material for lithography was less than 10% (Evaluation A). Moreover, as a result of evaluating the solubility in PGMEA, it was 10 mass% or more (evaluation A), and the obtained film forming material for lithography was evaluated as having excellent solubility.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the bismaleimide compound and stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

<Example 4>
As an oxazine compound, 10 parts by mass of benzoxazine BF-BXZ was used alone to form a film forming material for lithography.
As a result of thermogravimetry, the thermogravimetric decrease at 400 ° C. of the obtained film forming material for lithography was less than 10% (Evaluation A). Moreover, as a result of evaluating the solubility in PGMEA, it was 10 mass% or more (evaluation A), and it was evaluated that the obtained film forming material for lithography had a required solubility.
90 parts by mass of PGMEA as a solvent was added to 10 parts by mass of the film forming material for lithography, and the mixture was stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

<Example 5>
As a bismaleimide compound, 10 parts by mass of BMI-70 was used. Further, 2 parts by mass of benzoxazine BF-BXZ was used, and 0.1 part by mass of Irgacure 184 (manufactured by BASF) was blended as a radical photopolymerization initiator to obtain a film forming material for lithography.
A composition for forming a film for lithography was prepared by adding 90 parts by weight of PGMEA as a solvent to 10 parts by weight of the bismaleimide compound in the film forming material for lithography and stirring the mixture at room temperature with a stirrer for at least 3 hours. .

前記ビスマレイミド化合物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 6>
As a bismaleimide compound, 10 parts by mass of BMI-50P was used. Further, 2 parts by mass of benzoxazine BF-BXZ was used, and 0.1 part by mass of Irgacure 184 (manufactured by BASF) 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 bismaleimide compound and stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

<Example 7>
As a bismaleimide compound, 10 parts by mass of BMI-1000P was used. Further, 2 parts by mass of benzoxazine BF-BXZ was used, and 0.1 part by mass of Irgacure 184 (manufactured by BASF) 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 bismaleimide compound and stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

<Example 8>
As a bismaleimide compound, 10 parts by mass of BMI-80 was used. Further, 2 parts by mass of benzoxazine BF-BXZ was used, and 0.1 part by mass of Irgacure 184 (manufactured by BASF) 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 bismaleimide compound and stirred at least at least 3 hours at room temperature with a stirrer to prepare a film forming composition for lithography.

<Production Example 1>
A four-necked flask with an internal volume of 10 L capable of bottoming was prepared, equipped with a Dimroth condenser, thermometer, and stirring blade. In this four-necked flask, in a nitrogen stream, 1.09 kg of 1,5-dimethylnaphthalene (7 mol, manufactured by Mitsubishi Gas Chemical Co., Ltd.), 2.1 kg of 40% by weight formalin aqueous solution (28 mol of formaldehyde, Mitsubishi Gas Chemical Co., Ltd.) )) And 98 mass% sulfuric acid (manufactured by Kanto Chemical Co., Ltd.) 0.97 ml were charged and reacted for 7 hours while refluxing at 100 ° C. under normal pressure. Then, 1.8 kg of ethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade) as a diluent solvent was added to the reaction solution, and after standing, the lower aqueous phase was removed. Further, neutralization and washing with water were performed, and ethylbenzene and unreacted 1,5-dimethylnaphthalene were distilled off under reduced pressure to obtain 1.25 kg of a light brown solid dimethylnaphthalene formaldehyde resin.
The molecular weight of the obtained dimethylnaphthalene formaldehyde resin was number average molecular weight (Mn): 562, weight average molecular weight (Mw): 1168, and dispersity (Mw / Mn): 2.08.

Subsequently, a four-necked flask having an internal volume of 0.5 L equipped with a Dimroth condenser, a thermometer, and a stirring blade was prepared. This four-necked flask was charged with 100 g (0.51 mol) of the dimethylnaphthalene formaldehyde resin obtained as described above and 0.05 g of paratoluenesulfonic acid in a nitrogen stream, and the temperature was raised to 190 ° C. Stir after heating for hours. Thereafter, 52.0 g (0.36 mol) of 1-naphthol was further added, and the temperature was further raised to 220 ° C. to react for 2 hours. After the solvent was diluted, neutralization and water washing were performed, and the solvent was removed under reduced pressure to obtain 126.1 g of a dark brown solid modified resin (CR-1).
The obtained resin (CR-1) was Mn: 885, Mw: 2220, and Mw / Mn: 2.51.
As a result of thermogravimetry (TG), the amount of thermogravimetry at 400 ° C. of the obtained resin was more than 25% (Evaluation C). Therefore, it was evaluated that application to high temperature baking was difficult.
As a result of evaluating the solubility in PGMEA, it was 10% by mass or more (Evaluation A), and was evaluated as having excellent solubility.
In addition, about said Mn, Mw, and Mw / Mn, it measured by performing the gel permeation chromatography (GPC) analysis on the following conditions, and calculating | requiring the molecular weight of polystyrene conversion.
Apparatus: Shodex GPC-101 (made by Showa Denko KK)
Column: KF-80M x 3
Eluent: THF 1mL / min
Temperature: 40 ° C

次いで、実施例１〜４、比較例１〜２のリソグラフィー用膜形成用組成物をシリコン基板上に回転塗布し、その後、２４０℃で６０秒間、さらに４００℃で１２０秒間ベークして、膜厚２００ｎｍの下層膜を各々作製した。前記４００℃でベーク前後の膜厚差から膜厚減少率（％）を算出して、各下層膜の膜耐熱性を評価した。そして、下記に示す条件にてエッチング耐性を評価した。
また、下記に示す条件にて、段差基板への埋め込み性、及び平坦性を評価した。 <Examples 1-4, Comparative Examples 1-2>
As in Examples 1 to 4, compositions for forming a film for lithography were prepared. Moreover, using the resin obtained in Production Example 1, compositions for film formation for lithography in Comparative Examples 1 and 2 were prepared. The composition of each composition is as shown in Table 1. In addition, the phenyl aralkyl type epoxy resin (NC-3000-L; made by Nippon Kayaku Co., Ltd.) as a crosslinking agent is represented by the following formula.

Next, the film forming compositions for lithography of Examples 1 to 4 and Comparative Examples 1 to 2 were spin-coated on a silicon substrate, and then baked at 240 ° C. for 60 seconds and further at 400 ° C. for 120 seconds to obtain a film thickness. Each 200 nm lower layer film was produced. The film thickness reduction rate (%) was calculated from the film thickness difference before and after baking at 400 ° C., and the film heat resistance of each lower layer film was evaluated. And etching resistance was evaluated on the conditions shown below.
Moreover, the embedding property to a level | step difference board | substrate and the flatness were evaluated on the conditions shown below.

<Examples 5 to 8>
As in Examples 5 to 8, compositions for forming a film for lithography were prepared. The composition of each composition is as shown in Table 2. Next, the film-forming composition for lithography of Examples 5 to 8 was spin-coated on a silicon substrate, then baked at 110 ° C. for 60 seconds to remove the solvent of the coating film, and then integrated exposure with a high-pressure mercury lamp. It was cured in an amount of 600 mJ / cm ² and an irradiation time of 20 seconds, and further baked at 400 ° C. for 120 seconds to produce 200 nm-thick underlayer films. The film thickness reduction rate (%) was calculated from the film thickness difference before and after baking at 400 ° C., and the film heat resistance of each lower layer film was evaluated. And etching resistance was evaluated on the conditions shown below.
Moreover, the embedding property to a level | step difference board | substrate and the flatness were evaluated on the conditions shown below.

[Evaluation of heat resistance of film]
<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%

[Etching test]
Etching device: RIE-10NR manufactured by Samco International
Output: 50W
Pressure: 4Pa
Time: 2min
Etching gas CF ₄ gas flow rate: O ₂ gas flow rate = 5: 15 (sccm)

[Evaluation of etching resistance]
Etching resistance was evaluated according to the following procedure.
First, under the same conditions as in Example 1, except that novolak (PSM4357 manufactured by Gunei Chemical Co., Ltd.) is used instead of the film forming material for lithography in Example 1, and the drying temperature is 110 ° C. Was made. And the above-mentioned etching test was done for the lower layer film of this novolak, and the etching rate at that time was measured.
Next, the etching test was similarly performed on the lower layer films of Examples 1 to 8 and Comparative Examples 1 and 2, and the etching rate at that time was measured.
Then, the etching resistance was evaluated according to the following evaluation criteria based on the etching rate of the novolak underlayer film. From a practical viewpoint, the following S evaluation is particularly preferable, and A evaluation and B evaluation are preferable.
<Evaluation criteria>
S: Etching rate is less than −30% as compared to the novolac lower layer film A: Etching rate is from −30% to less than −20% as compared to the novolac lower layer film B: Etching rate as compared to the novolac lower layer film However, it is -20% or more to less than -10%.

[Evaluation of step board embedding]
Evaluation of the embeddability to the stepped substrate was performed according to the following procedure.
The composition for forming a lower layer 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 lower layer film. A cross section of the obtained film was cut out and observed with an electron beam microscope, and the embedding property to the stepped substrate was evaluated.
<Evaluation criteria>
A: The lower layer film is embedded in the concavo-convex part of the 60 nm line and space SiO ₂ substrate without defects.
C: There is a defect in the concavo-convex part of the 60 nm line and space SiO ₂ substrate, and the lower layer film is not embedded.

[Evaluation of flatness]
The composition for film formation obtained above is formed on a SiO ₂ stepped substrate in which a trench (aspect ratio: 1.5) having a width of 100 nm, a pitch of 150 nm and a depth of 150 nm and a trench (open space) having a width of 5 μm and a depth of 180 nm are mixed. Each object was applied. Thereafter, baking was performed 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 the resist underlayer film is observed with a scanning electron microscope (“S-4800” manufactured by Hitachi High-Technologies Corporation), and the difference between the maximum value and the minimum value of the resist underlayer film on the trench or space (ΔFT) 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 flat)
C: 40 nm ≦ ΔFT (poor flatness)

<Example 9>
The composition for forming a film for lithography in Example 1 was applied onto a 300 nm thick SiO ₂ substrate and baked at 240 ° C. for 60 seconds and further at 400 ° C. for 120 seconds to form a lower layer film having a thickness of 70 nm. did. On this lower layer film, an ArF resist solution was applied and baked at 130 ° C. for 60 seconds to form a 140 nm-thick photoresist layer. The resist solution for ArF is prepared by blending a compound of the following formula (22): 5 parts by mass, triphenylsulfonium nonafluoromethanesulfonate: 1 part by mass, tributylamine: 2 parts by mass, and PGMEA: 92 parts by mass. What was done was used.
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, 0.38 g of azobisisobutyronitrile, The reaction solution was dissolved in 80 mL. This reaction solution was polymerized for 22 hours while maintaining the reaction temperature at 63 ° C. in a nitrogen atmosphere, and then the reaction solution was dropped into 400 mL of n-hexane. The product resin thus obtained was coagulated and purified, and the resulting white powder was filtered and dried overnight at 40 ° C. under reduced pressure 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.

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

<Example 10>
A positive resist pattern was obtained in the same manner as in Example 9, 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 above. . The evaluation results are shown in Table 3.

<Example 11>
A positive resist pattern was obtained in the same manner as in Example 9, 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. . The evaluation results are shown in Table 3.

<Example 12>
A positive resist pattern was obtained in the same manner as in Example 9, 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. . The evaluation results are shown in Table 3.

<Comparative Example 3>
A photoresist layer was directly formed on the SiO ₂ substrate in the same manner as in Example 9 except that the lower layer film was not formed to obtain a positive resist pattern. The evaluation results are shown in Table 3.

[Evaluation]
About each of Examples 9-12 and the comparative example 3, the shape of the obtained resist pattern of 55 nmL / S (1: 1) and 80 nmL / S (1: 1) was made into the electron microscope made from Hitachi, Ltd. ( S-4800). As for the shape of the resist pattern after development, the resist pattern was not collapsed and the rectangular shape was good, and the resist pattern was evaluated as bad. As a result of the observation, the minimum line width with no pattern collapse and good rectangularity was used as an evaluation index as the resolution. Furthermore, the minimum amount of electron beam energy that can draw a good pattern shape is used as an evaluation index as sensitivity.

  As is clear from Table 3, Examples 9 to 12 using the composition for forming a film for lithography of the present embodiment containing a benzoxazine compound were significantly higher in resolution and sensitivity than Comparative Example 3. It was confirmed to be excellent. In addition, it was confirmed that the resist pattern shape after development did not collapse and the rectangularity was good. Furthermore, the difference in the resist pattern shape after development shows that the lower layer films of Examples 9 to 12 obtained from the compositions for film formation for lithography of Examples 1 to 4 have good adhesion to the resist material. It was.

The film forming material for lithography of the present embodiment has relatively high heat resistance and relatively high solvent solubility, is excellent in embedding characteristics in a stepped substrate and film flatness, and can be applied to a wet process. Therefore, the composition for forming a film for lithography containing the film forming material for lithography can be used widely and effectively in various applications that require these performances. In particular, the present invention can be used particularly effectively in the field of the lower layer film for lithography and the lower layer film for multilayer resist.

Claims (15)

  A film forming material for lithography containing an oxazine compound.   2. The film formation for lithography according to claim 1, wherein the oxazine compound includes a condensed ring of a 6-membered ring containing one oxygen atom, one nitrogen atom and four carbon atoms as ring member atoms, and an aromatic ring. material. The film forming material for lithography according to claim 2, wherein the oxazine compound is at least one selected from the group consisting of compounds represented by the following formulas (a) to (f).

[Where:
R ¹ and R ² are independently an organic group having 1 to 30 carbon atoms,
R ^{3 to} R ⁶ are independently hydrogen or a hydrocarbon group having 1 to 6 carbon atoms,
X represents a single bond, —O—, —S—, —S—S—, —SO ₂ —, —CO—, —CONH—, —NHCO—, —C (CH ₃ ) ₂ —, —C (CF _{3) 2 -, - (CH} 2) m -, - O- (CH 2) m -O-, or -S- (CH ₂₎ a _m -S-,
m is an integer of 1-6,
Y is independently a single bond, —O—, —S—, —CO—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or alkylene having 1 to 3 carbon atoms. ]. Group of the following formula (0):

(In formula (0), each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms)
The film forming material for lithography according to any one of claims 1 to 3, further comprising a compound having:   The film forming material for lithography according to any one of claims 1 to 4, further comprising a crosslinking agent.   The cross-linking agent is at least one selected from the group consisting of a phenol compound, an epoxy compound, a cyanate compound, an amino compound, a melamine compound, a guanamine compound, a glycoluril compound, a urea compound, an isocyanate compound, and an azide compound. The film forming material for lithography described in 1.   The film forming material for lithography according to any one of claims 1 to 6, further comprising a crosslinking accelerator.   The film forming material for lithography according to claim 1, further comprising a radical polymerization initiator.   The composition for film formation for lithography containing the film formation material for lithography as described in any one of Claims 1-8, and a solvent.   The film forming composition for lithography according to claim 9, further comprising an acid generator.   The composition for forming a film for lithography according to claim 10, wherein the film for lithography is an underlayer film for lithography.   A lithographic underlayer film formed using the lithographic film forming composition according to claim 11. Forming a lower layer film on the substrate using the film forming composition for lithography according to claim 11;
Forming at least one photoresist layer on the lower layer film, and irradiating a predetermined region of the photoresist layer with radiation to perform development;
A resist pattern forming method. Forming a lower layer film on the substrate using the film forming composition for lithography according to claim 11;
Forming an intermediate layer film on the lower layer film using a resist intermediate layer film material containing silicon atoms;
Forming at least one photoresist layer on the intermediate layer film;
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;
A step of etching the lower layer film using the obtained intermediate layer film pattern as an etching mask, and a step of forming a pattern on the substrate by etching the substrate using the obtained lower layer film pattern as an etching mask,
A circuit pattern forming method. A step of dissolving the film forming material for lithography according to any one of claims 1 to 8 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
The purification method in which the solvent used in the step of obtaining the organic phase includes a solvent that is not arbitrarily miscible with water.