JP2004169012A - Porous organic film-forming composition, porous organic film-forming method and porous organic insulating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous organic film-forming composition capable of producing an insulating film having a low dielectric constant, to provide a method for forming the insulating film having the low dielectric constant, and to provide the insulating film having the low dielectric constant. <P>SOLUTION: This porous organic film-forming composition contains (A) an aromatic polymer having units expressed by the formula (Ar<SP>1</SP>is a residue having an aromatic ring; X and Z are each a direct bond, a bivalent saturated hydrocarbon residue, -CR<SP>1</SP>=CR<SP>2</SP>-, -C≡C-, a bivalent residue having an aromatic ring, a bivalent residue having an alicyclic hydrocarbon ring, -O-, -CO-, -COO-, -S-, -SO- or -SO<SB>2</SB>-; and Y is a bivalent saturated hydrocarbon residue, -CR<SP>3</SP>=CR<SP>4</SP>-, -C≡C-, a bivalent residue having an aromatic ring or a bivalent residue having an alicyclic hydrocarbon ring) or a monomer having at least two -C≡C- residues in its molecule and (B) a thermally vaporizing compound and/or a thermally decomposing polymer. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a composition for forming a porous organic film, a method for forming a porous organic film, and a porous organic insulating film.

2. Description of the Related Art In recent years, in electronic materials, delay time due to an increase in inter-wiring resistance and an increase in electric capacity has become a serious problem with higher integration, higher speed, and higher performance of semiconductors. In order to reduce the delay time and increase the speed of the device, it is necessary to lower the relative dielectric constant of the interlayer insulating film. Therefore, development of a material capable of manufacturing an insulating film having a low dielectric constant has been advanced. ing.
As a material for the low dielectric constant insulating film, for example, a composition comprising a polymer obtained by oxidatively polymerizing an aromatic compound containing two or more ethynyl groups in the molecule in the presence of a catalyst is known. Thus, the insulating film obtained from the composition had a relative dielectric constant of 2.7 to 2.9, which was not a satisfactory level.

JP 2002-155233 A

  An object of the present invention is to provide a composition for forming a porous organic film capable of producing a low dielectric constant insulating film, to provide a method for forming a low dielectric constant insulating film, and to provide a low dielectric constant insulating film. Is to provide.

（１）
（式（１）中、Ａｒ¹は、−Ｃ≡ＣＨ基以外の基で置換されていてもよい芳香環を有する基を表わし、ＸおよびＺは、それぞれ独立に、直接結合、置換されていてもよい炭素数１〜２０の２価の飽和炭化水素基、−ＣＲ¹＝ＣＲ²−、−Ｃ≡Ｃ−、置換されていてもよい芳香環を有する２価の基、置換されていてもよい炭素数４〜２０の脂環式炭化水素環を有する２価の基、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−Ｓ−、−ＳＯ−、または−ＳＯ₂−を表わし、Ｙは、置換されていてもよい炭素数１〜２０の２価の飽和炭化水素基、−ＣＲ³＝ＣＲ⁴−、−Ｃ≡Ｃ−、置換されていてもよい芳香環を有する２価の基、または置換されていてもよい炭素数４〜２０の脂環式炭化水素環を有する２価の基を表わし、Ｒ¹〜Ｒ⁴は、それぞれ独立に、水素原子を表わすか、置換されていてもよい炭素数１〜２０のアルキル基、置換されていてもよい炭素数１〜２０のアルコキシ基、置換されていてもよい炭素数４〜２０の脂環式炭化水素基、または置換されていてもよいアリール基を表わし、ｎは１以上の整数を表わす。） That is, the present invention provides a composition for forming a porous organic film comprising the following (A) and (B), and a step of applying the composition to a substrate and then performing a heat treatment at 400 ° C. or lower. The present invention relates to a method for forming an organic film and a porous organic insulating film obtained by the method.
(A) An aromatic polymer having a repeating unit represented by the following formula (1) or a monomer having at least two —C≡CH groups in a molecule.
(B) a heat transpiration compound and / or a heat decomposition compound.

(1)
(In the formula (1), Ar ¹ represents a group having an aromatic ring which may be substituted with a group other than a —C≡CH group, and X and Z are each independently directly bonded or substituted. divalent saturated hydrocarbon group having carbon atoms which may ^{1~20, -CR 1 = CR 2 -} , - C≡C-, 2 -valent group having an aromatic ring which may be substituted, may be substituted divalent group having an alicyclic hydrocarbon ring optionally having 4 to 20 carbon atoms, -O -, - CO -, - COO -, - S -, - SO-, or -SO ₂ - represents, Y is , divalent saturated hydrocarbon group substituted carbon atoms and optionally ^{1~20, -CR 3 = CR 4 -} , - C≡C-, 2 -valent group having an aromatic ring which may be substituted, Or a divalent group having an optionally substituted alicyclic hydrocarbon ring having 4 to 20 carbon atoms, wherein R ^{1 to} R ⁴ each independently represent hydrogen Represents an atom or an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, an alicyclic group having 4 to 20 carbon atoms which may be substituted Represents a hydrocarbon group or an aryl group which may be substituted, and n represents an integer of 1 or more.)

  ADVANTAGE OF THE INVENTION According to this invention, the composition for porous organic film formation which can manufacture a low dielectric constant insulating film, the method of forming a low dielectric constant insulating film, and a low dielectric constant insulating film are provided.

The composition for forming a porous organic film of the present invention contains the following (A) and (B).
(A) An aromatic polymer having a repeating unit represented by the above formula (1) or a monomer having at least two —C≡CH groups in a molecule.
(B) a heat transpiration compound and / or a heat decomposition compound.

In the formula (1), Ar ¹ represents a group having an aromatic ring which may be substituted with a group other than a —C≡CH group.
Examples of the group having an aromatic ring include groups having a benzene ring, diphenyl ring, naphthalene ring, anthracene ring, fluorene ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, and triazine ring.
Examples of the substituent other than -C≡CH group include an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, a trialkylsilyl group which may have a substituent, a hydroxyl group. And the like.
Examples of the alkyl group as a substituent include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group.
Examples of the alkoxy group as a substituent include a methoxy group, an ethoxy group, and a propoxy group.
Examples of the alkenyl group as a substituent include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a 2-methylallyl group, and a butadienyl group.
Examples of the alkynyl group other than the substituent —C≡CH group include a propargyl group, a butynyl group, a pentynyl group, a butadiynyl group, and a heptynyl group.
Examples of the aryl group as a substituent include a phenyl group, a diphenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidyl group, a pyridazinyl group, and a triazinyl group.
Examples of the trialkylsilyl group as a substituent include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and a dimethylethylsilyl group.

As Ar ¹ , for example, a group having a bond at two positions on an aromatic ring shown below can be mentioned.

X and Z are each independently a direct bond, a divalent saturated hydrocarbon group substituted carbon atoms and optionally ^{1~20, -CR 1 = CR 2 -} , - C≡C-, substituted A divalent group having a good aromatic ring, a divalent group having an optionally substituted alicyclic hydrocarbon ring having 4 to 20 carbon atoms, -O-, -CO-, -COO-, -S —, —SO—, or —SO ₂ —, wherein Y is an optionally substituted divalent saturated hydrocarbon group having 1 to 20 carbon atoms, —CR ³ ＣＲCR ⁴ —, and —C≡C—. A divalent group having an optionally substituted aromatic ring, or a divalent group having an optionally substituted alicyclic hydrocarbon ring having 4 to 20 carbon atoms.

The case where X or Z is a direct bond means that Ar ¹ and Y are directly bonded.

As the divalent saturated hydrocarbon group having 1 to 20 carbon atoms in X, Y and Z, an alkylene group having 1 to 20 carbon atoms is preferable, and examples thereof include a methylene group, an ethylene group, an n-propylene group, an isopropylene group and a butylene. Group, isobutylene group, pentylene group, hexylene group and the like.
Examples of the substituent of the divalent saturated hydrocarbon group having 1 to 20 carbon atoms include an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, and a trialkyl which may have a substituent. Examples include a silyl group and a hydroxyl group.
Examples of the alkoxy group, alkenyl group, alkynyl group other than -C≡CH group, aryl group and trialkylsilyl group which may have a substituent include those described above.

R ¹ and R ² of —CR ¹ ＣＲCR ² — in X and Z, and R ³ and R ⁴ of —CR ³ ＣＲCR ⁴ — in Y each independently represent a hydrogen atom or are substituted. An alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms which may be substituted, an alicyclic hydrocarbon group having 4 to 20 carbon atoms which may be substituted, or Represents an aryl group.

Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group.
Examples of the substituent of the alkyl group having 1 to 20 carbon atoms include an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, a trialkylsilyl group which may have a substituent, and a hydroxyl group. And the like.
Examples of the alkoxy group, alkenyl group, alkynyl group other than -C≡CH group, aryl group and trialkylsilyl group which may have a substituent include those described above.

Examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a pentyloxy group, and a hexyloxy group.
Examples of the substituent of the alkoxy group having 1 to 20 carbon atoms include an alkyl group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, a trialkylsilyl group which may have a substituent, and a hydroxyl group. And the like.
Examples of the alkyl group, alkenyl group, alkynyl group other than -C≡CH group, aryl group, and trialkylsilyl group which may have a substituent include those described above.

Examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, an adamantyl group, and a norbornyl group.
Examples of the substituent of the alicyclic hydrocarbon group having 4 to 20 carbon atoms may include an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, and a substituent. Examples include a trialkylsilyl group and a hydroxyl group.
Examples of the alkyl group, the alkoxy group, the alkenyl group, the alkynyl group other than -C≡CH group, the aryl group, and the trialkylsilyl group which may have a substituent include those described above.

Examples of the aryl group include a phenyl group, a diphenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidyl group, a pyridazinyl group, and a triazinyl group.
Examples of the substituent of the aryl group include an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, a trialkylsilyl group which may have a substituent, and a hydroxyl group.
Examples of the alkyl group, alkoxy group, alkenyl group, alkynyl group other than —C−CH group, and trialkylsilyl group which may have a substituent include those described above.

Examples of —CR ¹ ＣＲCR ² — and —CR ³ ＣＲCR ⁴ — include the following groups.

Examples of the divalent group having an alicyclic hydrocarbon having 4 to 20 carbon atoms in X, Y and Z include, for example, a group having a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, an adamantane ring, and a norbornene ring And the like.
Examples of the substituent of the divalent group having an alicyclic hydrocarbon having 4 to 20 carbon atoms include an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, an aryl group, and a substituent. And a trialkylsilyl group and a hydroxyl group which may be present.
Examples of the alkyl group, the alkoxy group, the alkenyl group, the alkynyl group other than -C≡CH group, the aryl group, and the trialkylsilyl group which may have a substituent include those described above.

（２）
式（２）で示される芳香環を有する２価の基としては、例えば、ベンゼン環、ジフェニル環、ナフタレン環、アントラセン環、フルオレン環、ピリジン環、ピラジン環、ピリミジン環、ピリダジン環、トリアジン環を有する基などが挙げられる。
これらの置換基としては、例えば、アルキル基、アルコキシ基、アルケニル基、−Ｃ≡ＣＨ基以外のアルキニル基、置換基を有してもよいトリアルキルシリル基、ヒドロキシル基などが挙げられる。
アルキル基、アルコキシ基、アルケニル基、−Ｃ≡ＣＨ基以外のアルキニル基、置換基を有してもよいトリアルキルシリル基としては、前記と同じものが挙げられる。 Examples of the divalent group having an aromatic ring in X, Y and Z include a group represented by the following formula (2) or the following formula (3).

(2)
Examples of the divalent group having an aromatic ring represented by the formula (2) include a benzene ring, a diphenyl ring, a naphthalene ring, an anthracene ring, a fluorene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring. And the like.
Examples of these substituents include an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group other than -C≡CH group, a trialkylsilyl group which may have a substituent, a hydroxyl group, and the like.
Examples of the alkyl group, alkoxy group, alkenyl group, alkynyl group other than —C−CH group, and trialkylsilyl group which may have a substituent include those described above.

（３）
式（３）中、Ａは、−ＣＲ⁵Ｒ⁶−、−ＣＲ⁷＝ＣＲ⁸−、−Ｃ≡Ｃ−、置換されていてもよい芳香環を有する２価の基、置換されてもよい脂環式炭化水素環を有する２価の基、−Ｏ−、または−ＣＯ−を表わす。
ここで、Ｒ⁵〜Ｒ⁸は、それぞれ独立に、水素原子、置換されていてもよい炭素数１〜２０のアルキル基、置換されていてもよい炭素数１〜２０のアルコキシ基、置換されていてもよい炭素数４〜２０の脂環式炭化水素基、または置換されていてもよいアリール基を表わす。
炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、炭素数４〜２０の脂環式炭化水素基、アリール基、およびこれらの置換基としては、前記と同じものが挙げられる。
−ＣＲ⁵Ｒ⁶−としては、例えば、メチレン基、エチリデン基、ｎ−プロピリデン基、イソプロピリデン基、ブチリデン基、イソブチリデン基、ペンチリデン基、へキシリデン基等が挙げられる。
−ＣＲ⁷＝ＣＲ⁸−としては、前記と同じものが挙げられる。

(3)
In the formula (3), A is —CR ⁵ R ⁶ —, —CR ⁷ ＣＲCR ⁸ —, —C≡C—, a divalent group having an optionally substituted aromatic ring, which may be substituted Represents a divalent group having an alicyclic hydrocarbon ring, -O-, or -CO-.
Here, R ^{5 to} R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted, an alkoxy group having 1 to 20 carbon atoms which may be substituted, Represents an alicyclic hydrocarbon group having 4 to 20 carbon atoms which may be substituted, or an aryl group which may be substituted.
Examples of the alkyl group having 1 to 20 carbon atoms, the alkoxy group having 1 to 20 carbon atoms, the alicyclic hydrocarbon group having 4 to 20 carbon atoms, the aryl group, and the substituents thereof include the same as those described above.
Examples of —CR ⁵ R ⁶ — include a methylene group, an ethylidene group, an n-propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, a hexylidene group and the like.
Examples of —CR ⁷ ＣＲCR ⁸ — include the same as those described above.

  Examples of the group represented by the formula (2) or the formula (3) include a benzene ring, a diphenyl ring, a naphthalene ring, an anthracene ring, a fluorene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring. Valence groups and the like.

From the viewpoint of heat resistance, examples of the divalent group having an aromatic ring in X, Y, and Z include those in which Ar ² in the above formula (2) is a phenylene group, a diphenylene group, or a naphthylene group; A in 3) is preferably a cyclohexylene group, -C≡C-, a phenylene group or a fluorenylene group, and more preferably A in the above formula (3) is -C≡C- or a fluorenylene group. preferable.

Examples of the aromatic polymer having the repeating unit represented by the formula (1) include polyarylenes, polyimides, polyarylene ethers, polyarylene ether ketones, polyarylene ether sulfones, and polyarylene ether amides. And the like, and polyarylenes or polyarylene ethers are preferable, and polyarylene ethers are more preferable.
In particular, in the formula (1), polyarylene ethers in which X and Z are -O- and Y is a divalent group having an aromatic ring are preferably used. Such a polymer having an ether bond in the main chain is preferably used because it has excellent heat resistance, insulating properties (relative dielectric constant of 3.0 or less), solubility in an organic solvent, and the like.
Further, those in which Y is represented by the above formula (3) and A is —C≡C— or a fluorenylene group at that time are more preferably used because of further excellent heat resistance.

  Furthermore, an epoxy group, a cyanate group, a propargyl group, an allyl group, a vinyl group, an ethynyl group, an alkylsilyl group, an alkoxysilyl group are provided on the main chain, side chain or terminal of the aromatic polymer having the repeating unit represented by the formula (1). It may have a crosslinkable group such as a group.

The weight average molecular weight in terms of polystyrene of the aromatic polymer having a repeating unit represented by the formula (1) by gel permeation chromatography (hereinafter, referred to as GPC) is preferably 50,000 or less, more preferably 30,000 or less. It is more preferably 10,000 or less.
When the molecular weight is large, the solubility in a solvent, the applicability to a substrate, and the like tend to be impaired.

（４） The monomer having at least two —C≡CH groups in the molecule is preferably a monomer having an aromatic ring.
Examples of the monomer include a monomer represented by the following formula (4).

(4)

In the formula (4), Ar ^{3 to} Ar ¹⁶ each independently represent a group having an aromatic ring which may be substituted with a group other than a —C≡C—H group.
Examples of the group having an aromatic ring and the substituent thereof include the same groups as in Ar ¹ described above.

Q ^{1 to} Q ⁸ each independently represent a direct bond, —C≡C—, —O—, —CO—, —COO—, —S—, —SO—, —SO ₂ —, or —C≡C Represents a divalent group having an alicyclic hydrocarbon ring having 4 to 20 carbon atoms which may be substituted with a group other than -H group.
Here, examples of the divalent group having an alicyclic hydrocarbon ring having 4 to 20 carbon atoms and the substituent thereof include the same as described above.

In the formula, R ^{9 to} R ¹² each independently represent a hydrogen atom, or an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms. Represents the formula (2), the formula (3), or a hydroxyl group, and has an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms, The formulas (2) and (3) may be substituted with groups other than -C−CH groups.
At least one of R ^{9 to} R ¹² is selected from a group having an aromatic ring which may be substituted with a group other than a —C−C—H group.
An alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 4 to 20 carbon atoms, the above formula (2), the above formula (3), a hydroxyl group, and a substituent thereof And the same as those described above.

  a represents an integer of 2 or more; b1, b2, c1 to c3, d1 to d3, e1 to e4, and f1 to f4 each independently represent an integer of 0 or more, b1 + b2, c1 + c2 + c3, d1 + d2 + d3, e1 + e2 + e3 + e4, f1 + f2 + f3 + f4 is an integer of 2 or more.

Specific examples of the monomer include, for example, a monomer represented by the following formula.

The weight average molecular weight in terms of polystyrene by GPC of a monomer having at least two —C≡CH groups in the molecule is preferably 5,000 or less, more preferably 3,000 or less, and even more preferably 1500 or less.
When the molecular weight is large, the proportion of —C≡CH groups in the molecule is reduced, so that the crosslink density is reduced and the relative permittivity tends to be insufficiently reduced.

The composition for forming a porous organic film of the present invention contains a heat-transpiration compound, a heat-decomposable compound, or a mixture thereof.
Assuming that the thermal decomposition onset temperature of the component (A) is Ta and the thermal transpiration onset temperature of the thermal transpiration compound of the component (B) or the thermal decomposition onset temperature of the thermal decomposable compound is Tb, Ta and Tb are Ta > Tb is preferably satisfied.
Further, Ta satisfies the relationship of Ta> Tb, and is more preferably a temperature exceeding 350 ° C., and further preferably a temperature exceeding 400 ° C. This is preferably performed in a thin film forming step in a manufacturing process of an electronic component, particularly a semiconductor device, usually at 350 ° C. or higher, more preferably at 400 ° C. or higher, and the porous organic film of the present invention has heat resistance to the temperature. It is because it is preferable to have the following.

Here, Tb is a temperature at the time of 5% weight loss measured by a TG / DTA (differential heat, thermogravimetric analyzer) under a nitrogen gas flow at a heating rate of 10 ° C./min. Tb is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 230 ° C. or lower, on the assumption that the relationship of Ta> Tb is satisfied. Further, Tb is preferably 200 ° C. or higher. In the case where a mixture is used as the component (B), Tb is a value measured for the mixture.
If Tb exceeds 300 ° C., at the insulating film formation end temperature, the heat-evaporating compound may not evaporate or the heat-decomposable compound may not be completely decomposed, and as a result, voids may not be formed. If it is less than 1, the heat-evaporable compound evaporates or the heat-decomposable compound is decomposed before the crosslinking of (A), and there is a tendency that voids cannot be formed.

Examples of the heat-evaporating compound include an adamantane derivative, a norbornene derivative, a hydroxynaphthalene derivative, and a hydroxyanthracene derivative.
Examples of the thermally decomposable compound include polystyrene derivatives, polyoxyalkylene derivatives, polyacrylate derivatives, polyalkylene glycol derivatives, polyurethane, polyamide, polyester, and polycarbonate.
Among these, a polystyrene derivative or a polyoxyalkylene derivative is preferably used.

As polystyrene derivatives, for example, polystyrene, polyvinyl toluene, polyvinyl xylene, poly α-methyl styrene, poly α-methyl vinyl toluene, poly α-methyl vinyl xylene, poly α-ethyl styrene, poly α-ethyl vinyl toluene, poly α -Ethylvinylxylene and the like.
Among them, polystyrene, polyvinyl toluene, poly α-methyl styrene, or poly α-methyl vinyl toluene is more preferable, and polystyrene or poly α-methyl styrene is more preferably used.
Examples of the polyoxyalkylene derivative include, for example, polyoxymethylene, polyoxyethylene, polyoxypropylene, polyoxyisopropylene, etc., and polyoxyethylene or polyoxypropylene is preferably used.
These are suitably used because the monomer after decomposition can evaporate at a temperature of 250 ° C. or more and does not generate waste.

  The method of addition polymerization of the thermally decomposable compound is not particularly limited, and examples thereof include radical polymerization, anionic polymerization, and cationic polymerization. Anionic polymerization is preferably used because the reaction can be easily controlled.

  In the addition polymerization of the thermally decomposable compound, the polymerization initiator, the modifying agent, the reaction terminator and the like may be appropriately changed in order to further improve the compatibility with the component (A).

Examples of the polymerization initiator include organometallic compounds such as metal aryl compounds and metal alkyl compounds, salts of triphenylmethylcarbonium ions, peroxides having an aromatic ring, and azo compounds having an aromatic ring.
Examples of the modifying agent include 1,1-diphenylethylene, 1,2-diphenylethylene (cis-form, trans-form), 1,1,2-triphenylethylene, 1-naphthyl-1-phenylethylene, and the like. .
Examples of the reaction terminator include water, methanol, an alkyl halide compound, and a carbonyl compound.

  The heat-evaporating compound or the heat-decomposable compound of the component (B) may be a copolymer obtained by polymerizing two or more monomers. As the copolymer, for example, polyoxymethylene-polyoxyethylene copolymer, polyoxymethylene-polyoxypropylene copolymer, polyoxyalkylene copolymer such as polyoxyethylene-polyoxypropylene copolymer, Styrene-methacrylate copolymer and the like.

  (B) The heat-evaporating compound and / or the heat-decomposable compound can be arbitrarily selected within a range in which the compatibility with the component (A) can be favorably maintained, and one kind or a combination of two or more kinds can be selected. Can be used.

The weight-average molecular weight in terms of polystyrene by GPC of the heat-evaporating compound or the heat-decomposable compound used as the component (B) is preferably 50,000 or less, more preferably 30,000 or less, and further preferably 10,000 or less. preferable.
If the molecular weight exceeds 50,000, the voids formed tend to be large.

The composition of the present invention contains (A) and (B), and may further contain an organic solvent to form a coating solution.
The organic solvent is not particularly limited as long as it can dissolve (A) and (B). Specific examples include methanol, ethanol, isopropanol, 1-butanol, 2-ethoxymethanol, alcohol solvents such as 3-methoxypropanol, acetylacetone, methyl ethyl ketone, methyl isobutyl ketone, 3-pentanone, 2-heptanone, 3-heptanone, Ketone solvents such as cyclohexanone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, methyl propionate, ethyl propionate, methyl butyrate, propylene glycol monomethyl ether acetate, ester solvents such as ethyl lactate, diisopropyl ether, dibutyl ether, Ether solvents such as dioxane, anisole, phenetole, veratrol, diphenyl ether, etc., and aromatic carbons such as benzene, toluene, mesitylene, ethylbenzene Hydrogen solvents, halogen solvents such as chloroform, chlorobenzene, dichloroethylene, and trichloroethylene; N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, etc. Examples thereof include amide solvents, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane. These are preferably used because they are easily available industrially.

  These organic solvents can be arbitrarily selected within a range in which the solubility of (A) and (B) and the coating property of the coating solution itself can be favorably maintained, and one type or a combination of two or more types can be used. You may.

  When used as a coating solution containing the organic solvent, the composition concentration of the coating solution for forming a porous organic film, that is, [((A) compounding amount + (B) compounding amount) / ((A) compounding amount + ( B) (Blending amount + organic solvent blending amount)] × 100 is preferably 5 to 30%. The concentration can be appropriately adjusted depending on the purpose of improving the thickness of the coating film, the step filling property, and the like.

The weight ratio of the compounding amount of (A) to the compounding amount of (B) in the composition for forming a porous organic film of the present invention is preferably from 99: 1 to 1:99, more preferably from 95: 5 to 95: 5. 30:70, more preferably 95: 5 to 50:50.
If the weight ratio (A) is too small or the weight ratio (B) is too large, the compatibility between (A) and (B) will deteriorate, and the voids formed will tend to increase. If the weight ratio (A) is too large or the weight ratio (B) is too small, the formed voids tend to be small, and the specific permittivity tends not to be sufficiently reduced.

The composition for forming a porous organic film of the present invention and the coating solution containing the composition may further contain additives.
Examples of the additive include a coupling agent such as a silane coupling agent and a titanium coupling agent, a surfactant, a foam stabilizer, and a catalyst such as an organic peroxide.
Coupling agents improve the adhesion to the substrate, surfactants improve the applicability or stabilize the porous state, and organic peroxides and other catalysts reduce the crosslinking temperature of (A). You may mix | blend each.

The composition for forming a porous organic film of the present invention and the coating solution containing the same may further contain an aromatic polymer having a crosslinkable group in the molecule.
The aromatic polymer having a crosslinkable group in the molecule is used, for example, for the purpose of improving the compatibility between (A) and (B), improving the flatness of the insulating film when porous, adjusting the thickness of the insulating film, and the like. May be blended.

  The aromatic polymer having a crosslinkable group in the molecule is not particularly limited as long as it has one or more crosslinkable groups in the molecule, for example, polyphenylenes, polyimides, polyarylene ethers, polyarylene Examples thereof include ether ketones, polyarylene ether sulfones, and polyarylene ether amides. In particular, a polymer having an ether bond in the main chain is preferably used because of its excellent heat resistance, insulating properties, solubility in a solvent, and the like. Among them, polyarylene ethers are more preferably used because they have a relative dielectric constant of 3.0 or less. Is done.

The aromatic polymer having a crosslinkable group in the molecule may be a random copolymer or a block copolymer, and may be a graft copolymer or a block copolymer having another polymer bonded to a side chain or a terminal group. It may be united.
The crosslinkable group may be on a side chain or a terminal group.
Examples of the crosslinkable group include a crosslinkable group such as a cyanate group, a propargyl group, an allyl group, a vinyl group, an ethynyl group, an alkylsilyl group, and an alkoxysilyl group.

  The weight average molecular weight in terms of polystyrene by GPC of the aromatic polymer having a crosslinkable group in the molecule is preferably 100,000 or less, more preferably 50,000 or less, and further preferably 30,000 or less.

The porous organic film is formed by applying the composition for forming a porous organic film of the present invention to a substrate and then performing a heat treatment at a temperature of Tb or more and Ta or less, following a crosslinking reaction, to generate voids. be able to.
The temperature of the heat treatment is preferably 400 ° C. or lower. By heating at 400 ° C. or lower, there is a tendency that decomposition of (A) can be suppressed.

Examples of the substrate include a substrate made of glass, quartz, metal, ceramic, silicon, GaAs, SiO ₂ , SiN, SiC, or the like.
Examples of the application method include spin coating, roller coating, dip coating, and spraying.
The coating liquid applied to the substrate is subjected to thermal evaporation or thermal decomposition of the phase formed in (B) at a temperature of 400 ° C. or less, that is, at a temperature of Tb or more and less than Ta, following the crosslinking reaction of (A), preferably Porosity is generated by generating voids having a pore diameter of 0.1 μm or less.
Further, the temperature may be maintained at an arbitrary temperature between Tb and Ta for a certain time.
The temperature from Tb to Ta is preferably from 250 ° C to 400 ° C, more preferably from 300 ° C to 380 ° C, even more preferably from 350 ° C to 370 ° C.
Examples of the method for crosslinking (A) include a heat treatment method and an ultraviolet irradiation method.
Examples of the heating method include a method using an oven, a hot plate, a furnace, and the like, a light irradiation heating using a xenon lamp by RTP (lamp heating heater), and the like.

The heat treatment is preferably performed in an atmosphere having an oxygen concentration of less than 1%, more preferably in an atmosphere having an oxygen concentration of less than 100 ppm.
Examples of the atmosphere having an oxygen concentration of less than 1% include a reduced-pressure atmosphere, an inert gas atmosphere, and a vacuum.
The reduced pressure atmosphere is preferably about 1 to 20 Pa.
Examples of the inert gas include helium, nitrogen, and argon.

Since the porous organic film obtained by using the composition for forming a porous organic film of the present invention can be crosslinked at a relatively low temperature, it can be easily produced in a short time.
Since the porous organic film has a low dielectric constant and excellent heat resistance and chemical resistance, it is suitably used as an insulating film for electronic materials such as semiconductors.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to Examples.

[Production Example 1] Synthesis of aromatic polymer A1 In a 500 mL four-necked flask, 9,9-bis (4-dihydroxyphenyl) fluorene (9.6 g), 1- (trimethylsilylethynyl) -2,4-difluorobenzene (5 0.4 g), potassium carbonate (10.4 g), dimethyl sulfoxide (150 g), and toluene (80 g), and then the reaction was carried out at 120 ° C. for 12 hours, at 130 ° C. for 2 hours, and at 150 ° C. for 4 hours. Thereafter, the reaction solution was added to a methanol / acetic acid solution to precipitate a product. The precipitated resin was filtered, washed with methanol and water, and dried to obtain a resin. The C≡C bond-containing aromatic polyether resin had a weight average molecular weight in terms of polystyrene of about 7600, and the ¹ H-NMR spectrum supported that the trimethylsilyl group was eliminated to form an HC≡C group. . This is designated as aromatic polymer A1.

[Production Example 2] Synthesis of aromatic polymer A2 In a 300 mL four-necked flask, 4,4'-dihydroxytran (4.2 g), 1- (trimethylsilylethynyl) -2,6-difluorobenzene (4.2 g), carbonic acid Potassium (9.3 g), dimethyl sulfoxide (45.0 g), and toluene (100 g) were added, and then the reaction was performed at 120 ° C. for 7.5 hr and at 130 ° C. for 5.5 hr. Thereafter, the reaction solution was added to a methanol / acetic acid solution to precipitate a product. The precipitated resin was filtered, washed with methanol and water, and dried to obtain a resin. The polystyrene-equivalent weight average molecular weight of the C 含有 C bond-containing aromatic polyether resin was about 110700, and the ¹ H-NMR spectrum supported that the trimethylsilyl group was eliminated to form an HC≡C group. . This is designated as aromatic polymer A2.

Production Example 3 Synthesis of Aromatic Polymer A3 9,9-bis (4-dihydroxyphenyl) fluorene (28.0 g), 1- (phenylethynyl) -3,5-difluorobenzene (15. 2 g), K ₂ CO ₃ (29.6 g), dimethyl sulfoxide (429 g), and toluene (229 g) were added, and the mixture was refluxed and dehydrated, and then reacted at 180 ° C. for 4 hours. Thereafter, the reaction solution was added to a methanol / acetic acid solution to precipitate a product. The precipitated resin was filtered, washed with methanol and water, and dried to obtain a resin. The weight average molecular weight in terms of polystyrene of the C≡C bond-containing aromatic polyether resin is about 8500, which is referred to as aromatic polymer A3.

[Production Example 4] Synthesis of compound A4 1,2,4,5-tetrabromobenzene (19.7 g) was charged into a 500 mL four-necked flask together with triethylamine (250 g) and Cu (I) I (1.1 g). It was left for 1 hr under an Ar gas flow. Pd (0) (TPP) ₄ (3.3 g), trimethylsilylacetylene (10.8 g) and phenylacetylene (11.3 g) were added, and the mixture was stirred at 80 ° C. for 6 hours, and then stirred at room temperature / overnight. Was. After filtration, the solvent was distilled off from the liquid layer, column treatment was carried out with a toluene solvent, and crystals were obtained by concentration. 100 g of methanol and 50 g of toluene were added to and dissolved in the crystals, and potassium carbonate (41.5 g) was further added, followed by stirring overnight. After neutralization with acetic acid, washing with water, and concentration, the target product was obtained. This is designated as compound A4.

[Production Example 5] Synthesis of compound A5 2,4-dibromophenol (25.2 g, 0.1 mol), difluorobenzophenone (10.9 g, 0.05 mol), potassium carbonate (20.7 g, 0 .15 mol), dimethyl sulfoxide (150 g), and toluene (80 g) were charged, and heated and stirred at 150 ° C. for 6 hours under an N ₂ stream. Toluene was added to the reaction mass, washed with water, and the solvent was distilled off to obtain a resinous substance. The obtained resin (17.0 g, 0.025 mol) was charged into a 500 mL four-necked flask together with 200 g of triethylamine and Cu (I) I (0.6 g, 0.003 mol), and allowed to stand under an Ar gas flow for 1 hour. Then, Pd (0) (TPP) ₄ (1.7 g, 0.0015 mol) and ethynylbenzene (12.4 g, 0.12 mol) were added thereto, and the mixture was stirred at 80 ° C. for 6 hours while keeping at room temperature / overnight. Stirring was performed. After filtration, the solvent was distilled off from the liquid layer, column treatment was performed with a toluene solvent, and the target product was obtained by concentration. This is designated as compound A5.

Production Example 6 Synthesis of Compound A6 In a 500 mL four-necked flask, 4,4 ′-(9H-fluoren-9-ylidene) bisphenol (8.8 g) and 1,3-dibromo-5-fluorobenzene (12.7 g) were placed. ), Potassium carbonate (13.8 g), toluene (100 g) and dimethyl sulfoxide (200 g) were charged, and the mixture was stirred at 120 ° C./5 hr under a nitrogen stream. Toluene, acetic acid and water were added and the mixture was separated, and the oil layer was distilled off under reduced pressure to obtain a tetrabromo-compound intermediate A6 '.
A 500 mL four-necked flask was charged with a part (11.6 g) of the intermediate A6 ′ obtained above, triethylamine (200 g), and CuI (I) (0.5 g), and was stirred at room temperature for 30 minutes under an Ar gas flow. Stirring was performed. After Pd (0) (TPP) ₄ (1.8 g) and trimethylsilylacetylene (7.9 g) were charged there, the temperature was raised to 80 ° C., and the mixture was stirred while keeping the temperature for 5 hours. The reaction mass was filtered, the filtrate was concentrated, and then subjected to a column treatment with toluene, followed by concentration to obtain a tetra (trimethylsilylethynyl) -form intermediate A6 ″.
The intermediate A6 ″ obtained above was directly charged into a 300 mL four-necked flask, and toluene (50 g), methanol (50 g), and potassium carbonate (11.6 g) were charged, and the mixture was stirred at room temperature for 18 hours. Was neutralized with acetic acid as it was, toluene was added thereto, and the mixture was washed with water, and then toluene was distilled off under reduced pressure to obtain a tetraethynyl monomer as compound A6.

[Production Example 7] Synthesis of compound A7 In a 500 mL four-necked flask, 1,1 ', 1 "-trihydroxyphenylethane (6.1 g), 1,3-dibromo-5-fluorobenzene (15.2 g), carbonic acid Potassium (13.8 g), toluene (100 g), and dimethyl sulfoxide (200 g) were charged, and the mixture was stirred while keeping the temperature at 120 ° C. for 5 hours under a nitrogen stream, and toluene, acetic acid, and water were added thereto to carry out liquid separation. Intermediate F1, which was a hexabromo compound, was obtained, using this hexabromo compound, ethynyl coupling and elimination of the protecting group in the same manner as in Production Example 4 to obtain compound A7.

[Production Example 8] Synthesis of compound A8 Instead of 4,4 '-(9H-fluoren-9-ylidene) bisphenol, 5,5'-(1,1-cyclohexylidene) bis- [1,1'- (Bisphenyl) -2-ol] (10.5 g) was used, and synthesis was performed in the same manner as in Production Example 6 to obtain an intermediate A8 ′ as a tetrabromo compound. Using this tetrabromo compound, ethynyl coupling and elimination of the protecting group were carried out in the same manner as in Production Example 6 to obtain compound A8.

[Production Example 9] Synthesis of thermally decomposable compound B1 Into a 2 L flask purged with nitrogen, α-methylstyrene (284 g), dichloromethane (284 g), and hexane (852 g) were charged and cooled to -60 ° C. Then concentrated sulfuric acid (24 g) was charged. After keeping the temperature at -60 ° C for 1 hour, methanol (24 g) was charged to stop the reaction. The mixture was heated to room temperature, diluted with dichloromethane (353 g), and washed with water. After liquid separation, the obtained resin solution was dropped into (6000 g) of methanol to precipitate the resin, which was filtered and taken out. (205 g) The resin had a polystyrene equivalent weight average molecular weight of about 4,600. This is designated as thermally decomposable compound B1.

[Production Example 10] Synthesis of thermally decomposable compound B2 Tetrahydrofuran (284 g) and α-methylstyrene (72 g) were charged into a 2 L flask purged with nitrogen. Under stirring, an n-butyllithium solution (54 g) was added dropwise to the flask. The flask was then cooled to −60 ° C. and stirred for 30 minutes. Next, a 20% solution of 1,1-diphenylethylene in tetrahydrofuran (165 g) was added dropwise to the flask and stirred for 30 minutes. Finally, methanol (6 g) was charged to stop the reaction. The temperature was raised to room temperature, and the obtained resin solution was dropped into 4000 g of methanol to precipitate the resin, which was then filtered and taken out. As a result, poly-α-methylstyrene having a weight-average molecular weight of 1300 and having a terminal modified with diphenylethylene was obtained. This is designated as thermally decomposable compound B2.

[Preparation of coating liquid]
The coating liquids (coating liquids 1 to 16) used in Examples 1 to 6 and Comparative Examples 1 to 10 were prepared as follows.
Coating liquid 1
A mixture of the aromatic polymer A1 obtained in Production Example 1 and the thermally decomposable compound B1 obtained in Production Example 9 at a ratio of 65:35 was adjusted with anisole to a composition concentration of 15% by weight. Further, the prepared solution was filtered through a 0.1 μm PTFE filter by a known method to prepare a coating solution.
Coating liquid 2
A coating solution was prepared in accordance with the coating solution 1 except that the aromatic polymer A2 obtained in Production Example 2 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 3
A coating solution was prepared in accordance with the coating solution 1 except that the compound A4 obtained in Production Example 4 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 4
A mixture of the compound A6 obtained in Production Example 6 and the thermally decomposable compound B2 obtained in Production Example 10 at a ratio of 65:35 was adjusted with anisole to a composition concentration of 15% by weight. Further, the prepared solution was filtered through a 0.1 μm PTFE filter by a known method to prepare a coating solution.
Coating liquid 5
A coating solution was prepared in the same manner as in the coating solution 4 except that the compound A7 obtained in Production Example 7 was used instead of the compound A6 obtained in Production Example 6.
Coating liquid 6
A coating solution was prepared in accordance with the coating solution 4 except that the compound A8 obtained in Production Example 8 was used instead of the compound A6 obtained in Production Example 6.
Coating liquid 7
The aromatic polymer A1 obtained in Production Example 1 was adjusted to a solid content of 10% by weight with anisole. Further, the prepared solution was filtered through a 0.1 μm PTFE filter by a known method to prepare a coating solution.
Coating liquid 8
A coating liquid was prepared in accordance with the coating liquid 7 except that the aromatic polymer A2 obtained in Production Example 2 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 9
A coating solution was prepared in accordance with the coating solution 7 except that the aromatic polymer A3 obtained in Production Example 3 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 10
A coating solution was prepared in accordance with the coating solution 7 except that the compound A4 obtained in Production Example 4 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 11
A coating solution was prepared in accordance with the coating solution 7 except that the compound A5 obtained in Production Example 5 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 12
A coating solution was prepared in accordance with the coating solution 7 except that the compound A6 obtained in Production Example 6 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 13
A coating solution was prepared in accordance with the coating solution 7 except that the compound A7 obtained in Production Example 7 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 14
A coating liquid was prepared in accordance with the coating liquid 7 except that the compound A8 obtained in Production Example 8 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 15
A coating liquid was prepared in accordance with the coating liquid 1 except that the aromatic polymer A3 obtained in Production Example 3 was used instead of the aromatic polymer A1 obtained in Production Example 1.
Coating liquid 16
A coating solution was prepared in accordance with the coating solution 1 except that the compound A5 obtained in Production Example 5 was used instead of the aromatic polymer A1 obtained in Production Example 1.

[Example 1]
About 1 ml of the prepared coating solution 1 was dropped on a 4-inch silicon wafer. Thereafter, the wafer was spun at 500 rpm for 3 seconds, and then spun at a speed of 2000 rpm for 15 seconds. The wafer coated in this way was baked at 150 ° C. for 1 minute. Next, the baked wafer was cured by holding it in a furnace in a nitrogen atmosphere at 400 ° C. for 30 minutes to decompose the thermal decomposition element. The relative dielectric constant of the obtained cured film was measured by a mercury probe method using a CV measurement (SSM495, manufactured by SSM, Inc.) at an operating frequency of 1 MHz. The results are shown in Tables 1 and 2.

[Example 2]
A coating film was manufactured according to Example 1 except that the coating solution 2 was used instead of the coating solution 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Example 3]
A coating film was manufactured according to Example 1 except that the coating liquid 3 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Example 4]
A coating film was manufactured according to Example 1 except that the coating solution 4 was used instead of the coating solution 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Example 5]
A coating film was manufactured according to Example 1 except that the coating solution 5 was used instead of the coating solution 1, and the relative dielectric constant was measured. The hardness and the elastic modulus were measured using a Hysitron TriboScope Micromechanical Test device manufactured by HYSITRON. The results are shown in Tables 1 and 2.

[Example 6]
A coating film was manufactured according to Example 1 except that the coating liquid 6 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 1]
A coating film was manufactured according to Example 1 except that the coating liquid 7 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 2]
A coating film was manufactured according to Example 1 except that the coating liquid 8 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Comparative Example 3]
A coating film was manufactured according to Example 1 except that the coating liquid 9 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 4]
A coating film was manufactured according to Example 1 except that the coating liquid 10 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Comparative Example 5]
A coating film was manufactured according to Example 1 except that the coating liquid 11 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Comparative Example 6]
A coating film was manufactured according to Example 1 except that the coating liquid 12 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 7]
A coating film was manufactured according to Example 1 except that the coating liquid 13 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 8]
A coating film was manufactured according to Example 1 except that the coating liquid 14 was used instead of the coating liquid 1, and the relative dielectric constant, hardness, and elastic modulus were measured. The results are shown in Tables 1 and 2.

[Comparative Example 9]
A coating film was manufactured according to Example 1 except that the coating liquid 15 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

[Comparative Example 10]
A coating film was manufactured according to Example 1 except that the coating liquid 16 was used instead of the coating liquid 1, and the relative dielectric constant was measured. The results are shown in Tables 1 and 2.

  The relative dielectric constants of the cured films of Examples 1 to 6 were 1.6 to 2.4, and were thermally decomposed into Comparative Examples 1 to 8 containing no thermally decomposable compound and compounds having no -C≡CH group. The dielectric constant is significantly lower than Comparative Examples 9 to 10 in which a conductive compound is blended.

As described above in detail, according to the present invention, a composition for forming a porous organic film, a method for forming a low dielectric constant insulating film, and a low dielectric constant insulating film capable of producing a low dielectric constant insulating film are provided. Is done.
Further, according to the present invention, it is possible to provide a composition for forming a porous organic film capable of producing a low-dielectric-constant insulating film having high hardness and elastic modulus.

Claims (11)

A composition for forming a porous organic film, comprising the following (A) and (B).
(A) An aromatic polymer having a repeating unit represented by the following formula (1) or a monomer having at least two —C≡CH groups in a molecule.
(B) a heat transpiration compound and / or a heat decomposition compound.

(1)
(In the formula (1), Ar ¹ represents a group having an aromatic ring which may be substituted with a group other than a —C≡CH group, and X and Z are each independently directly bonded or substituted. divalent saturated hydrocarbon group having carbon atoms which may ^{1~20, -CR 1 = CR 2 -} , - C≡C-, 2 -valent group having an aromatic ring which may be substituted, may be substituted divalent group having an alicyclic hydrocarbon ring optionally having 4 to 20 carbon atoms, -O -, - CO -, - COO -, - S -, - SO-, or -SO ₂ - represents, Y is , divalent saturated hydrocarbon group substituted carbon atoms and optionally ^{1~20, -CR 3 = CR 4 -} , - C≡C-, 2 -valent group having an aromatic ring which may be substituted, Or a divalent group having an optionally substituted alicyclic hydrocarbon ring having 4 to 20 carbon atoms, wherein R ^{1 to} R ⁴ each independently represent hydrogen Represents an atom or an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkoxy group having 1 to 20 carbon atoms, an alicyclic group having 4 to 20 carbon atoms which may be substituted Represents a hydrocarbon group or an aryl group which may be substituted, and n represents an integer of 1 or more.)   The composition according to claim 1, wherein Y is a divalent group having an optionally substituted aromatic ring.   3. The composition according to claim 1, wherein the aromatic polymer is a polyarylene or a polyarylene ether.   The composition according to any one of claims 1 to 3, wherein the monomer having at least two -C≡CH groups in the molecule is a monomer having an aromatic ring.   The composition according to any one of claims 1 to 4, wherein the component (B) is polystyrene, poly α-methylstyrene, polyoxyethylene, or polyoxypropylene.   The composition according to any one of claims 1 to 5, wherein the polystyrene-equivalent weight molecular weight of the thermally decomposable compound is 50,000 or less.   The composition according to any one of claims 1 to 6, wherein the relationship between the thermal decomposition start temperature Ta of (A) and the thermal evaporation or thermal decomposition start temperature Tb of (B) is Ta> Tb.   A method for forming a porous organic film, comprising a step of applying the composition according to any one of claims 1 to 7 to a substrate and then performing a heat treatment at 400 ° C or lower.   9. The method according to claim 8, wherein the step of performing a heat treatment is a step of performing a heat treatment at an oxygen concentration of less than 1%.   The method according to claim 9, wherein the step of performing the heat treatment is a step of performing a heat treatment under reduced pressure, an inert gas atmosphere, or a vacuum. A porous organic insulating film obtained by the method according to claim 8.