JP2010070727A - Composition for forming insulating film, insulating film, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming an insulating film forming a film exhibiting a low dielectric constant, high mechanical strength, and high heat resistance, an insulating film obtained by using the above composition, a method for producing the insulating film by using the above composition, and an electronic device having the insulating film as a structural layer. <P>SOLUTION: The composition for forming an insulating film comprises a polymer containing repeating units having a branched structure represented by general formula (1). In the general formula (1), X is a cage structure; Y is an aromatic hydrocarbon group; R<SP>1</SP>is an aromatic hydrocarbon group; R<SP>2</SP>is a substituent; (*) is a bonding site; (a) is an integer of 0-18; (b) is an integer of 0-6; (c) is an integer of 2-7; and (d) is an integer of 1-3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composition for forming an insulating film, an insulating film obtained by using the composition, a method for producing the insulating film, and an electronic device having the insulating film.

  In recent years, in the field of electronic materials, with the progress of higher integration, more functions, and higher performance, circuit resistance and capacitor capacity between wirings have increased, leading to an increase in power consumption and delay time. In particular, an increase in delay time is a major factor in reducing the signal speed of the device and the occurrence of crosstalk. Therefore, in order to reduce the delay time and speed up the device, it is necessary to reduce parasitic resistance and parasitic capacitance. It has been. As a specific measure for reducing this parasitic capacitance, an attempt has been made to cover the periphery of the wiring with a low dielectric interlayer insulating film. The interlayer insulating film is required to have excellent heat resistance that can withstand a subsequent process such as a thin film formation process, chip connection, and pinning when manufacturing a mounting substrate, and chemical resistance that can withstand a wet process. Furthermore, in recent years, low resistance Cu wiring is being introduced from Al wiring, and along with this, planarization by CMP (Chemical Mechanical Polishing) has become common, and high mechanical strength that can withstand this process is high. It has been demanded.

  Polybenzoxazole, polyimide, polyarylene (ether), and the like have been disclosed as organic polymer-based interlayer insulating films for a long time. However, in order to realize a high-speed device, a material having a lower dielectric constant is desired. Introducing heteroatoms such as oxygen, nitrogen, sulfur and aromatic hydrocarbon units into the polymer molecule as in these materials, the dielectric constant increases due to high molar polarization, and over time due to moisture absorption. In some cases, the dielectric constant may increase, and further problems may occur that impair the reliability of the electronic device.

On the other hand, a polymer composed of saturated hydrocarbons has an advantage that it exhibits a lower dielectric constant because its molar polarization is smaller than that of a polymer composed of heteroatom-containing units or aromatic hydrocarbon units. However, for example, a polymer composed of a highly flexible hydrocarbon such as polyethylene has insufficient heat resistance and cannot be used for electronic device applications.
Patent Document 1 discloses a polymer in which adamantane or diamantane, which is a saturated hydrocarbon having a rigid cage structure, is introduced into a molecule. In order to realize a high-speed device, its characteristics (dielectric constant) are disclosed. , Heat resistance, mechanical strength, etc.) are not always satisfactory, and in particular, there has been a strong demand for further reduction of the dielectric constant.

JP 2005-522528 A

  In view of the above circumstances, the present invention uses an insulating film forming composition capable of forming a film exhibiting a low dielectric constant, high mechanical strength, and high heat resistance, and the insulating film forming composition. It is an object to provide an insulating film to be obtained, a method for producing an insulating film using the composition for forming an insulating film, and an electronic device having the insulating film as a constituent layer.

  As a result of intensive studies, the present inventors have found that a polymer having a predetermined repeating unit and a high degree of branching exhibits excellent solubility in a solution, and a film obtained from a composition containing this polymer is processed. It has been found that it has excellent properties, good surface shape, low dielectric constant and high heat resistance.

  That is, the present inventors have found that the above problem is solved by the following <1> to <7> configurations.

<1> The composition for insulating film formation containing the polymer containing the repeating unit which has a branched structure represented by General formula (1).

(In general formula (1), X represents a cage structure, Y represents an aromatic hydrocarbon group, R ¹ represents an aromatic hydrocarbon group, and R ² represents a substituent. “*”. Represents a bonding position, a represents an integer of 0 to 18, b represents an integer of 0 to 6, c represents an integer of 2 to 7, and d represents an integer of 1 to 3.)
<2> The RMS radius (nm) and molar molecular weight (g / mol) of the polymer measured using GPC (gel permeation chromatography) -MALLS (multi-angle light scattering detector), Plotting on a log-log graph with the RMS radius (nm) on the vertical axis and the molar molecular weight (g / mol) on the horizontal axis, the slope of the resulting straight line is 0.25 to 0.60 (nm / (g / mol) The composition for forming an insulating film according to <1>, which is a polymer having a degree of branching.
<3> The composition for forming an insulating film according to <1> or <2>, wherein the aromatic hydrocarbon group represented by Y in the general formula (1) is a benzene ring group.
<4> The composition for forming an insulating film according to any one of <1> to <3>, wherein the cage structure in the general formula (1) is adamantane, biadamantane, or diamantane.
<5> The polymer is selected from the group consisting of a repeating unit represented by the general formula (2), a repeating unit represented by the general formula (3), and a repeating unit represented by the general formula (4). The composition for forming an insulating film according to any one of <1> to <4>, which is a polymer having at least one kind.

(In General Formula (2) to General Formula (4), R ¹ represents an aromatic hydrocarbon group. R ² represents a substituent. “*” Represents a bonding position. E represents 0 to 6. An integer, f represents an integer of 0 to 4, g represents an integer of 2 to 7, and h represents an integer of 1 to 2.)
<6> A film forming step of forming a coating film by applying the insulating film forming composition according to any one of <1> to <5> on the substrate;
The manufacturing method of an insulating film provided with the hardening process which irradiates the said coating film with the high energy ray of an electron beam or an ultraviolet-ray, and is hardened.
<7> An insulating film formed using the insulating film forming composition according to any one of <1> to <5>.
<8> An electronic device having the insulating film according to <7>.

  According to the present invention, an insulating film forming composition capable of forming a film exhibiting a low dielectric constant, high mechanical strength, and high heat resistance, an insulating film obtained using the insulating film forming composition, and the insulating film A method for producing an insulating film using the film forming composition and an electronic device having the insulating film as a constituent layer can be provided.

Below, the composition for insulating film formation concerning this invention, the insulating film obtained from this composition for insulating film formation, and the manufacturing method of an insulating film are demonstrated in detail.
First, the polymer which has a repeating unit represented by General formula (1) contained in the composition for insulating film formation is demonstrated.

<Polymer containing a repeating unit represented by the general formula (1) having a branched structure>
The composition for insulating film formation of this invention contains the polymer containing the repeating unit represented by General formula (1). In addition, the repeating unit represented by General formula (1) has a branched structure. By using this polymer having a branched structure in the main chain, a film having a low dielectric constant and excellent heat resistance can be obtained.

(In general formula (1), X represents a cage structure, Y represents an aromatic hydrocarbon group, R ¹ represents an aromatic hydrocarbon group, and R ² represents a substituent. “*”. Represents a bonding position, a represents an integer of 0 to 18, b represents an integer of 0 to 6, c represents an integer of 2 to 7, and d represents an integer of 1 to 3.)

  In general formula (1), X represents a cage structure. In the present invention, the “cage structure” is a molecule whose volume is determined by a plurality of rings formed by covalently bonded atoms, and a point located within the volume cannot leave the volume without passing through the ring. Point to. For example, an adamantane structure is considered a cage structure. In contrast, a cyclic structure having a single bridge, such as norbornane (bicyclo [2.2.1] heptane), is not considered a cage structure because the ring of the single bridged cyclic compound does not define volume. .

  The cage structure of the present invention may contain either a saturated or unsaturated bond and may contain a heteroatom such as oxygen, nitrogen or sulfur, but a saturated hydrocarbon is preferred from the viewpoint of a low dielectric constant.

  The cage structure of the present invention is preferably a structure such as adamantane, biadamantane, diamantane, triamantane, tetramantane or dodecahedran, and more preferably adamantane, biadamantane or diamantane from the viewpoint of low dielectric properties and heat resistance. is there.

The cage structure represented by X in the general formula (1) is an (a + c + 1) -valent group. More specifically, in the general formula (1), X is a group that is bonded to Y, has a R ¹ groups, and is bonded to other c repeating units. Especially, as a valence of X, 3-6 valence is preferable and 3-4 are more preferable.

  Y in the general formula (1) represents an aromatic hydrocarbon group. 6 to 25 carbon atoms are preferable, 6 to 15 carbon atoms are more preferable, and 6 to 10 carbon atoms are particularly preferable. Specifically, benzene ring group, naphthalene ring group, biphenyl ring group, anthracene ring group, tetracene ring group, pentacene ring group, phenanthrene ring group, pyrene ring group, 9,9-diphenylfluorene ring group, tetraphenylmethane ring Group, a spirobifluorene ring group, etc., preferably a benzene ring group, a naphthalene ring group, more preferably a benzene ring group.

In general formula (1), R ¹ represents an aromatic hydrocarbon group. It does not specifically limit as an aromatic hydrocarbon group, Furthermore, you may have arbitrary substituents. 6 to 25 carbon atoms are preferable, 6 to 15 carbon atoms are more preferable, and 6 to 10 carbon atoms are particularly preferable. Specifically, benzene ring group, naphthalene ring group, biphenyl ring group, anthracene ring group, tetracene ring group, pentacene ring group, phenanthrene ring group, pyrene ring group, 9,9-diphenylfluorene ring group, tetraphenylmethane ring Group, a spirobifluorene ring group, etc., preferably a benzene ring group, a naphthalene ring group, more preferably a benzene ring group.

Any substituent on the aromatic hydrocarbon group represented by R ¹ may be any substituent as long as the effects of the present invention are not impaired. Specifically, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (a linear, branched, or cyclic alkyl group, such as a bicycloalkyl group or a group having a cage structure) It may be a polycyclic alkyl group, preferably having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2 -An ethylhexyl group, a cyclohexyl group, a cyclopentyl group, an adamantyl group, etc.), an alkenyl group (a straight chain, a branched chain, or cyclic may be sufficient. C2-C20 is preferable and C2-C10 is more preferable. Specifically, a vinyl group, an allyl group, a prenyl group, etc. are mentioned), an alkynyl group (straight chain, branched chain, or cyclic may be sufficient, and C2-C20 is preferable. The carbon number is more preferably 2 to 10. Specific examples include an ethynyl group and a phenylethynyl group, and an aryl group (specifically, a phenyl group, a naphthyl group, an anthracene group, a phenanthrene group, a tetracene group, Pentacene group, fluorene group), heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (the carbamoyl group having a substituent includes, for example, N-hydroxycarbamoyl group, N -Acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, N- (alkyl or aryl) carbamoyl group, N, N-di (alkyl or aryl) carbamoyl Group), carbazo A group containing a repeating unit containing a ruthenium group, a carboxy group or a salt thereof, an oxalyl group, an oxamoyl group, a cyano group, a carbonimidoyl group (Carbonimidoyl group), a formyl group, a hydroxy group, an alkoxy group (an ethyleneoxy group or a propyleneoxy group) Including), aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic) amino group, acylamino group , Sulfonamide group, ureido group, thioureido group, N-hydroxyureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydra Dino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyamino group, nitro group, quaternized nitrogen atom (For example, pyridinio group, imidazolio group, quinolinio group, isoquinolinio group), isocyano group, imino group, mercapto group, (alkyl, aryl, or heterocyclic) thio group, (alkyl, aryl, or heterocyclic ring) ) Dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group (the sulfamoyl group having a substituent includes, for example, N-acylsulfamoyl group, N- Sulfonylsulfamoyl group) or a salt thereof Phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, and a silyl group. These groups may further have an arbitrary substituent.
Of these, preferably an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, adamantyl group, etc.), carbon number 2 -10 alkenyl group (vinyl group, allyl group, prenyl group, etc.), C2-C10 alkynyl group (ethynyl group, phenylethynyl group, etc.), C6-C20 aryl group (phenyl group, naphthyl group, Anthracene group etc.), C1-C10 alkoxy group (methoxy group, ethoxy group etc.), C6-C20 aryloxy group (phenoxy group etc.), C1-C10 acyloxy group (acetoxy group etc.) , A silyl group having 0 to 20 carbon atoms (trimethylsilyl group, triphenylsilyl group, trimethoxysilyl group, etc.). These groups may further have an arbitrary substituent.
More preferably, an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, adamantyl group, etc.), 10 alkenyl groups (vinyl group, allyl group, prenyl group, etc.), C2-C10 alkynyl groups (ethynyl group, phenylethynyl group, etc.), C6-C20 aryl groups (phenyl group, naphthyl group, anthracene) Particularly preferably an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, adamantyl group, etc.). And an alkynyl group having 2 to 10 carbon atoms (such as ethynyl group and phenylethynyl group).

In general formula (1), R ² represents a substituent. Any substituent may be used as long as the effects of the present invention are not impaired. Specifically, it is the same as the specific example of the arbitrary substituents substituted on the aromatic hydrocarbon group represented by R ¹ described above.
Of these, preferably an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, etc.), Alkenyl group (vinyl group, allyl group, prenyl group, etc.), C2-C10 alkynyl group (ethynyl group, phenylethynyl group, etc.), C6-C20 aryl group (phenyl group, naphthyl group, anthracene group, etc.) ), An alkoxy group having 1 to 10 carbon atoms (methoxy group, ethoxy group and the like), and an aryloxy group having 6 to 20 carbon atoms (phenoxy group and the like). These groups may further have an arbitrary substituent.
More preferably, an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, etc.), alkenyl having 2 to 10 carbon atoms. Group (vinyl group, allyl group, prenyl group, etc.), C2-C10 alkynyl group (ethynyl group, phenylethynyl group, etc.), particularly preferably C1-C10 alkyl group (methyl group, ethyl group). Propyl group, isopropyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, cyclopentyl group, etc.).

  In the general formula (1), “*” represents a bonding position with the repeating unit represented by the general formula (1) contained in the polymer or another repeating unit. In the general formula (1), X has c bonds and Y has d bonds. In the general formula (1), it is preferable that c bonds connected to X are bonded to d bonds connected to Y of the repeating unit represented by the other general formula (1).

In general formula (1), a represents the integer of 0-18. Especially, 0-6 are more preferable and 0-2 are especially preferable.
In general formula (1), b represents the integer of 0-6. Especially, 0-4 are more preferable and 0-2 are especially preferable.
In general formula (1), c represents an integer of 2 to 7. Especially, 2-5 are more preferable and 2-3 are especially preferable.
In general formula (1), d represents an integer of 1 to 3. Especially, 1-2 are more preferable and 1 is especially preferable.

  Although the weight average molecular weight (Mw) of the polymer containing the repeating unit having a branched structure represented by the general formula (1) is not particularly limited, 500 to 1,000,000 is preferable, 1000 to 500,000 is more preferable, and 2000 to 300,000. Is more preferable. If the molecular weight is too small, it may volatilize by heating and the film thickness may decrease. If the molecular weight is too large, the solubility in an organic solvent may be insufficient, or the viscosity may increase and the cured film may lack smoothness.

Content of the repeating unit represented by General formula (1) in the polymer containing the repeating unit which has a branched structure represented by General formula (1) is not specifically limited, All repeating units ( 100 mol%) is preferably 20 mol% or more, more preferably 50 mol% or more, and even more preferably 80 mol% or more. The upper limit is 100 mol%.
In addition, mol% of the repeating unit represented by General formula (1) means the total mol% of the repeating unit derived from X which comprises General formula (1), and the repeating unit derived from Y.

  The polymer containing a repeating unit having a branched structure represented by the general formula (1) has a repeating unit other than the repeating unit represented by the general formula (1) as long as the effects of the present invention are not impaired. It may be. For example, you may have a repeating unit derived from the cage structure (adamantane, diamantane) which does not have a branched structure as represented by the following general formula (W-1)-general formula (W-3). .

In General Formula (W-1) to General Formula (W-3), R ³ represents a substituent. i represents an integer of 0 to 4. * Represents a binding position. The substituent represented by R ³ has the same meaning as the substituent represented by R ² in the general formula (1), and the preferred range is also the same.
i represents an integer of 0 to 4. Especially, it is preferably 0-2, more preferably 0-1.

The polymer containing a repeating unit having a branched structure represented by the general formula (1) preferably has a high degree of branching. Specifically, the degree of branching of the polymer is determined by the RMS radius (nm) and molar molecular weight (g / mol) measured using GPC (gel permeation chromatography) -MALLS (multi-angle light scattering detector). ) Is shown by the slope of a straight line obtained by plotting in a log-log graph in which the RMS radius (nm) is the vertical axis and the molar molecular weight (g / mol) is the horizontal axis. More specifically, the slope of this straight line corresponds to A in the following linear approximation formula.
log ₁₀ (RMS radius) = A · log ₁₀ (mole molecular weight) + B (A and B are constants)
When the slope (A) is 0.33, 0.60, and 1.00 (nm / (g / mol)), the molecular chain corresponds to a spherical shape, a random coil shape, and a linear shape, respectively, and this slope is small. It means that the degree of branching is high.
In the polymer having a repeating unit represented by the general formula (1) of the present invention, the slope of the above-mentioned RMS radius-mole molecular weight log-log line is 0.25 to 0.60 (nm / (g / mol)). It is preferably 0.25 to 0.55 (nm / (g / mol)), more preferably 0.35 to 0.51 (nm / (g / mol)). preferable.

  Among the polymers containing a repeating unit having a branched structure represented by the general formula (1), from the viewpoint of dielectric properties and heat resistance, the repeating unit represented by the general formula (2), represented by the general formula (3) A polymer having at least one selected from the group consisting of a repeating unit represented by formula (4) and a repeating unit represented by formula (4) is preferred.

(In General Formula (2) to General Formula (4), R ¹ represents an aromatic hydrocarbon group. R ² represents a substituent. “*” Represents a bonding position. E represents 0 to 6. An integer, f represents an integer of 0 to 4, g represents an integer of 2 to 7, and h represents an integer of 1 to 2.)

In General Formula (2) to General Formula (4), R ¹ represents an aromatic hydrocarbon group. Definition of aromatic hydrocarbon group represented by R ¹ are the same as those defined for R ¹ in general formula (1). Note that the bonding position of R ¹ is not particularly limited.
In General Formula (2) to General Formula (4), R ² represents a substituent. The definition of the substituent represented by R ² is the same as the definition of R ² in the general formula (1) described above. In addition, the bonding position of R ² on the benzene ring group is not particularly limited.

  In general formula (2) to general formula (4), “*” represents a bonding position with the repeating unit represented by general formula (2) to general formula (4) contained in the polymer or other repeating unit. Represents. In the general formulas (2) to (4), the adamantane group or diamantane group has g bonds, and the benzene ring group has h bonds. In general formula (1), g bonds connected to the adamantane group or diamantane group are h bonds connected to the benzene ring group of the repeating unit represented by other general formula (1). Bonding is preferred.

In general formula (2)-general formula (4), e represents the integer of 0-6. Especially, it is preferably 0-4, more preferably 0-2.
In general formula (2)-general formula (4), f represents the integer of 0-4. Especially, it is preferably 0-2, more preferably 0-1.
In General Formula (2) to General Formula (4), g represents an integer of 2 to 7. Especially, it is preferably 2-5, more preferably 2-3.
In general formula (2)-general formula (4), h represents the integer of 1-2. Among these, 1 is preferable.

  Preferred examples of the repeating unit represented by the general formula (2) to the general formula (4) include a repeating unit represented by the general formula (5), a repeating unit represented by the general formula (6), and a general formula ( 7) and the repeating unit represented by the general formula (8).

In General Formula (5) to General Formula (8), R ¹ represents an aromatic hydrocarbon group. Definition of aromatic hydrocarbon group represented by R ¹ are the same as those defined for R ¹ in general formula (1).
In General Formula (5) to General Formula (8), R ² represents a substituent. The definition of the substituent represented by R ² is the same as the definition of R ² in the general formula (1) described above.
In general formula (5)-general formula (8), e represents the integer of 0-6. Especially, it is preferably 0-4, more preferably 0-2.
In general formula (5)-general formula (8), f represents the integer of 0-4. Especially, it is preferably 0-2, more preferably 0-1.

  Specific examples of the repeating unit represented by the general formula (1) are described below, but the present invention is not limited thereto. In the following formula, “*” in the repeating unit is preferably bonded to “**” in the other repeating unit.

  Although the specific example of repeating units other than the repeating unit represented by General formula (1) below is described, this invention is not limited to these.

(Synthesis method)
A method for synthesizing the polymer represented by the general formula (1) containing a repeating unit having a branched structure is not particularly limited, and can be synthesized by combining known methods. For example, it can be synthesized by polymerizing a cage compound having two or more halogen atoms or hydroxy groups and an aromatic compound by Friedel-Crafts reaction.
Examples of the cage compound having two or more halogen atoms include commercially available 1,3-dibromoadamantane, J. Chem. Soc. Perkin Trans. 1, vol. 23, 3527-3530 (1999). 1,3-dibromo-5,7-dimethyladamantane, J. Org. Chem., Vol.39, 2995-3003 (1974), etc. Examples thereof include 1,6-dibromodiamantane and 4,9-dibromodiamantane. Examples of cage compounds having two or more hydroxy groups include commercially available 1,3-adamantanediol, 1,3,5-adamantanetriol, J. Org. Chem., Vol.39, 2987-2994 (1974 1,6-diamantanediol, 4,9-diamantanediol and the like which can be synthesized by the method described in the above.
Examples of aromatic compounds include benzene, toluene, anisole, o-xylene, m-xylene, p-xylene, t-butylbenzene, octylbenzene, 1,4-di-t-butylbenzene, 1,3-di -T-butylbenzene, 1,3,5-tri-t-butylbenzene, (trimethylsilyl) benzene and the like.

The Friedel-Crafts reaction for synthesizing the polymer of the present invention is preferably carried out in the presence of Lewis acid or Bronsted acid. Examples of Lewis acids include aluminum tribromide, aluminum trichloride, gallium trichloride, iron trichloride, antimony pentachloride, zirconium tetrachloride, tin tetrachloride, titanium tetrachloride, titanium tetrabromide, boron tribromide, Boron trichloride, boron trifluoride, trimethoxyboron, zinc dichloride, beryllium dichloride, cadmium dichloride, lanthanoid trihalides, alkylaluminum halides, aluminum trialkyls, aluminum alkoxides, silver triflate, cerium triflate, hafnium triflate , Lanthanum triflate, scandium triflate, thallium triflate, ytterbium triflate, bismuth triflate, trimethylsilyl triflate, titanocentriflate, dialkylboron triflate, ska Indium triflyl imide, scandium tri furyl methide, oxovanadium triflate, trimethylsilyl furyl imide, trimethylsilyl iodide and the like are preferably used.
Examples of Bronsted acid include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, fluorosulfonic acid, hydrofluoric acid, phosphoric acid, (trifluoromethanesulfonyl) imide, tris ( (Trifluoromethanesulfonyl) methane, solid acids such as zeolite and perfluorosulfonic acid resin, a mixture of hydrogen fluoride and antimony pentafluoride, a mixture of fluorosulfuric acid and antimony pentafluoride, and the like are preferably used.

  In the Friedel-Crafts reaction for synthesizing the polymer of the present invention, it is preferable to use a solvent. The cage compound and aromatic compound as reaction raw materials are soluble at room temperature or by heating, and Lewis acid or Bronsted. There is no particular limitation as long as it is inert to the acid. For example, water, alcohol solvents, ketone solvents, ester solvents, carbonate solvents, ether solvents, aromatic hydrocarbon solvents, amide solvents, halogen solvents, aliphatic hydrocarbon solvents can be used. . Among these, more preferred solvents are aromatic hydrocarbon solvents, halogen solvents, and aliphatic hydrocarbon solvents, specifically chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene. Nitrobenzene, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, carbon disulfide, nitromethane and the like. These may be used alone or in admixture of two or more.

  The concentration of the solid content (raw material cage compound and aromatic compound) in the polymerization solvent is preferably 1 to 50% by mass, more preferably 3 to 20% by mass.

  Optimum conditions for the polymerization reaction vary depending on the raw material cage compound and aromatic compound, polymerization catalyst, type of solvent, concentration, etc., but preferably the internal temperature is 0 ° C to 150 ° C, more preferably 0 ° C to 100 ° C. , Preferably 0.1 to 48 hours, more preferably 0.2 to 24 hours.

<Insulating film forming composition>
The composition for insulating film formation of this invention contains the polymer containing the repeating unit which has a branched structure represented by the above-mentioned general formula (1). The content of the polymer in the composition for forming an insulating film is appropriately selected in accordance with the purpose of use. This polymer may be used alone or in combination of two or more.

The composition for forming an insulating film may contain other insulating film resin or a precursor thereof in addition to the polymer as long as the effects of the present invention are not impaired.
The insulating film resin or its precursor is not particularly limited as long as it is a resin compound or its precursor compound that forms an insulating film, and the relative dielectric constant of the formed film is 4.0 or less, preferably 3.0. The following resin compounds or precursors thereof are preferred. Examples thereof include highly heat-resistant resins such as polyarylene resins, polyarylene ether resins, polybenzoxazole resins, polyquinoline resins, and polyquinoxaline resins, precursors of these resins, and compounds having a cage structure.

  Specific examples of the high heat-resistant resin that can be used for the insulating film resin or its precursor include polybenzoxazole described in JP-A-11-322929, JP-A-2003-12802, and JP-A-2004-18593, JP-A-2001-2899, quinoline resin, JP-T-2003-530464, JP-T-2004-535497, JP-T-2004-504424, JP-T-2004-504455, JP-T-2005-501131 No. 2005, No. 2005-516382, No. 2005-514479, No. 2005-522528, JP-A 2000-1000080, US Pat. No. 6,509,415, 11-214382, JP-A-2001-332542 Japanese Patent Laid-Open Nos. 2003-252882, 2003-292878, 2004-2787, 2004-67877, and 2004-59444 Examples thereof include polyimides described in JP-A-2525292 and JP-A-2004-26850.

The composition for forming an insulating film of the present invention may contain an organic solvent. Although it does not specifically limit as an organic solvent, For example, alcohol solvents, such as methanol, ethanol, 2-propanol, 1-butanol, 2-ethoxymethanol, 3-methoxypropanol, 1-methoxy-2-propanol, acetone, acetylacetone , Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 3-heptanone, cyclopentanone, cyclohexanone, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, ethyl propionate, propyl propionate, propion Acid ester, isobutyl propionate, propylene glycol monomethyl ether acetate, ester solvents such as methyl lactate, ethyl lactate, γ-butyrolactone, diisopropyl ether, dibutyl Ether solvents such as ether, ethylpropyl ether, anisole, phenetole, veratrol, aromatic hydrocarbon solvents such as mesitylene, ethylbenzene, diethylbenzene, propylbenzene, t-butylbenzene, amides such as N-methylpyrrolidone, dimethylacetamide A solvent etc. are mentioned, These may be used individually or in mixture of 2 or more types.
More preferred organic solvents are 1-methoxy-2-propanol, propanol, acetylacetone, cyclohexanone, propylene glycol monomethyl ether acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolactone, anisole, mesitylene, t-butylbenzene, Particularly preferred are 1-methoxy-2-propanol, cyclohexanone, 2-heptanone, propylene glycol monomethyl ether acetate, ethyl lactate, γ-butyrolactone, t-butylbenzene and anisole.

  The solid content concentration when the composition for forming an insulating film of the present invention contains the above organic solvent is preferably 1 to 50% by mass, more preferably 2 to 15% by mass, and particularly preferably 3 to 10%. % By mass. Here, the solid content is a component corresponding to all components constituting a film obtained using this composition, and does not include an organic solvent.

<Additive to composition for insulating film formation>
Furthermore, the composition for forming an insulating film of the present invention includes a radical generator and colloidal silica as long as the properties of the obtained insulating film (heat resistance, dielectric constant, mechanical strength, coatability, adhesion, etc.) are not impaired. In addition, additives such as a surfactant, a silane coupling agent, and an adhesion promoter may be added.

  The insulating film forming composition of the present invention may contain colloidal silica. For example, it is a dispersion in which high-purity silicic acid is dispersed in a hydrophilic organic solvent or water. is there.

  The composition for forming an insulating film of the present invention may contain a surfactant. For example, nonionic surfactants, anionic surfactants, cationic surfactants, and the like, silicone surfactants, fluorine-containing surfactants, polyalkylene oxide surfactants, acrylic surfactants Agents. The surfactant that can be used in the present invention may be one type or two or more types. As the surfactant, silicone surfactants, nonionic surfactants, fluorine-containing surfactants, and acrylic surfactants are preferable, and silicone surfactants are particularly preferable. The content of the surfactant that can be used in the present invention is preferably 0.01 to 1.0% by mass, and preferably 0.1 to 0.5% by mass with respect to the total amount of the film-forming coating solution. More preferably it is.

  In the present invention, the silicone-based surfactant is a surfactant containing at least one Si atom. The silicone surfactant used in the present invention may be any silicone surfactant and preferably has a structure containing alkylene oxide and dimethylsiloxane. A structure including the following chemical formula is more preferable.

  In the above formula, R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, x is an integer of 1 to 20, and a and b are each independently an integer of 2 to 100. Further, when there are a plurality of R, they may be the same or different.

  Examples of silicone surfactants that can be used in the present invention include BYK306, BYK307 (manufactured by BYK Chemie), SH7PA, SH21PA, SH28PA, SH30PA (manufactured by Toray Dow Corning Silicone), Troysol S366 (manufactured by Troy Chemical) And so on.

  The nonionic surfactant that can be used in the present invention may be any nonionic surfactant. For example, polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, polyoxyethylene dialkyl esters, sorbitan fatty acid esters, fatty acid-modified polyoxyethylenes, polyoxyethylene-polyoxypropylene block copolymers, etc. Can do.

  The fluorine-containing surfactant that can be used in the present invention may be any fluorine-containing surfactant. For example, perfluorooctyl polyethylene oxide, perfluorodecyl polyethylene oxide, perfluorodecyl polyethylene oxide and the like can be mentioned.

  The acrylic surfactant that can be used in the present invention may be any acrylic surfactant. For example, a (meth) acrylic acid type copolymer is mentioned.

  Any silane coupling agent may be used in the present invention. Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-aminoglycidyloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 1 -Methacryloxypropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3 -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarboni -3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-trimethoxysilylpropyltriethylenetriamine, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- Bis (oxyethylene) 3-aminopropyl trimethoxysilane, etc. N- bis (oxyethylene) -3-aminopropyltriethoxysilane and the like. The silane coupling agent that can be used in the present invention may be used alone or in combination of two or more.

  Any adhesion promoter may be used in the present invention. Examples of the adhesion promoter include trimethoxysilylbenzoic acid, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane. , Β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, trimethoxyvinylsilane, γ-aminopropyltriethoxysilane, aluminum monoethylacetoacetate diisopropylate, vinyltris (2-methoxyethoxy) silane, N- (2 -Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylto Limethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, Dimethylvinylethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, N, N'-bis (trimethylsilyl) urea, dimethyltrimethylsilylamine, trimethylsilylimidazole, vinyltrichlorosilane, benzotriazole, benzimidazole, indazole, imidazole , 2-mercaptobenzimidazole, 2-mercaptobenzothiazole , Mention may be made of 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, mercaptopyrimidine, 1,1-dimethylurea, 1,3-dimethylurea, and thiourea compounds. Functional silane coupling agents are preferred as adhesion promoters. The amount of the adhesion promoter used is preferably 10 parts by mass or less, more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the total solid content.

In the present invention, within the range allowed by the mechanical strength of the film, the film can be made porous by using a pore forming factor to achieve a low dielectric constant. The pore-forming factor as an additive that serves as a pore-forming agent is not particularly limited, but a nonmetallic compound is preferably used, and is soluble in a solvent used in an insulating film-forming coating solution. It is necessary to simultaneously satisfy the compatibility with the resin or its precursor.
A polymer can also be used as the pore forming agent. Examples of the polymer that can be used as the pore-forming agent include polyvinyl aromatic compounds (polystyrene, polyvinyl pyridine, halogenated polyvinyl aromatic compounds, etc.), polyacrylonitrile, polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.), polyethylene, poly Lactic acid, polysiloxane, polycaprolactone, polycaprolactam, polyurethane, polymethacrylate (such as polymethyl methacrylate) or polymethacrylic acid, polyacrylate (such as polymethyl acrylate) and polyacrylic acid, polydiene (such as polybutadiene and polyisoprene), polyvinyl chloride , Polyacetal, and amine-capped alkylene oxide, other polyphenylene oxide, poly (dimethyl) Siloxane), polytetrahydrofuran, poly cyclohexyl ethylene, polyethyl oxazoline, polyvinyl pyridine, may be a polycaprolactone.
In particular, polystyrene can be suitably used as a pore forming agent. Examples of polystyrene include anionic polymerized polystyrene, syndiotactic polystyrene, unsubstituted and substituted polystyrene (for example, poly (α-methylstyrene)), and unsubstituted polystyrene is preferred.

Further, the boiling point or decomposition temperature of the pore-forming agent is preferably 100 to 500 ° C, more preferably 200 to 450 ° C, and particularly preferably 250 to 400 ° C. The molecular weight is preferably 200 to 50,000, more preferably 300 to 10,000, and particularly preferably 400 to 5,000. The addition amount is preferably 0.5 to 75% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 1 to 20% by mass with respect to the solid content of the composition for forming an insulating film.
Further, as a pore forming factor, the insulating film resin or its precursor may contain a decomposable group, and its decomposition temperature is preferably 100 to 500 ° C., more preferably 200 to 450 ° C., particularly Preferably it is 250-400 degreeC. The content of the decomposable group is preferably 0.5 to 75 mol%, more preferably 0.5 to 30 mol%, and particularly preferably 1 to 1 mol with respect to the insulating film resin or its precursor forming the film. 20 mol%.

The composition for forming an insulating film of the present invention preferably has a sufficiently low metal content as an impurity. The metal concentration of the composition for forming an insulating film can be measured with high sensitivity by the ICP-MS method, and the metal content other than the transition metal in that case is preferably 30 ppm or less, more preferably 3 ppm or less, particularly preferably. 300 ppb or less.
In addition, the transition metal has a high catalytic ability to promote oxidation, and from the viewpoint of increasing the dielectric constant of the film obtained in the present invention by an oxidation reaction in the prebaking and thermosetting processes, the content is preferably smaller. Preferably it is 10 ppm or less, More preferably, it is 1 ppm or less, Most preferably, it is 100 ppb or less.
The metal concentration of the composition for forming an insulating film can also be evaluated by performing total reflection fluorescent X-ray measurement on a film obtained using the composition for forming an insulating film of the present invention. When a W (tungsten) ray is used as an X-ray source, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pd can be observed as metal elements, each of which is 100 × 10 ¹⁰ atoms. · Cm ⁻² or less is preferable, 50 × 10 ¹⁰ atom · cm ⁻² or less is more preferable, and 10 × 10 ¹⁰ atom · cm ⁻² or less is particularly preferable. Moreover, Br which is halogen is also observable, and the residual amount is preferably 10,000 × 10 ¹⁰ atom · cm ⁻² or less, more preferably 1,000 × 10 ¹⁰ atom · cm ⁻² or less, and 400 × 10 ^10. Atom · cm ⁻² or less is particularly preferable. Further, although Cl can be observed as halogen, the remaining amount is preferably 100 × 10 ¹⁰ atom · cm ⁻² or less from the viewpoint of damaging a CVD apparatus, an etching apparatus, etc., and 50 × 10 ¹⁰ atom · cm ^−2. The following is more preferable, and 10 × 10 ¹⁰ atom · cm ⁻² or less is particularly preferable.

  The method for producing the above-mentioned composition for forming an insulating film is not particularly limited. For example, a polymer containing a repeating unit having a branched structure represented by the general formula (1), an organic solvent, and each of the above optional components are added. A method of stirring using a stirrer such as a mixing mixer can be used.

  The composition for forming an insulating film of the present invention is preferably used for film formation after removing insolubles, gelled components and the like by filtering. The pore diameter of the filter used at that time is preferably 0.001 to 0.2 μm, more preferably 0.003 to 0.05 μm, and most preferably 0.01 to 0.03 μm. The material of the filter is preferably PTFE, polyethylene, or nylon, and more preferably polyethylene or nylon.

<Film formation process>
The film obtained using the composition for forming an insulating film of the present invention can be obtained, for example, by applying the composition for forming an insulating film to a substrate by any method such as spin coating, roller coating, dip coating, or scanning. Thus, a coating film can be obtained and, if necessary, the solvent can be removed by heat treatment or the like. As a method of applying to the substrate, a spin coating method or a scanning method is preferable. Particularly preferred is the spin coating method.
For spin coating, commercially available equipment can be used. For example, a clean truck series (manufactured by Tokyo Electron Co., Ltd.), D-spin series (manufactured by Dainippon Screen Mfg. Co., Ltd.), SS series or CS series (manufactured by Tokyo Ohka Kogyo Co., Ltd.) can be preferably used. The spin coating conditions may be any rotational speed, but from the viewpoint of in-plane uniformity of the film, a rotational speed of about 1,300 rpm is preferable for a 300 mm silicon substrate.
In addition, the composition solution discharge method may be either dynamic discharge in which the composition solution is discharged onto a rotating substrate or static discharge in which the composition solution is discharged onto a stationary substrate. From the viewpoint of uniformity, dynamic ejection is preferable. In addition, from the viewpoint of suppressing the consumption of the composition, it is also possible to use a method in which only the main solvent of the composition is preliminarily discharged onto the substrate to form a liquid film, and then the composition is discharged from there. it can. The spin coating time is not particularly limited, but is preferably within 180 seconds from the viewpoint of throughput. Further, from the viewpoint of transporting the substrate, it is also preferable to perform processing (edge rinse, back rinse) so as not to leave the film at the edge portion of the substrate.

As the substrate used is not particularly limited, for example, a silicon wafer, SiO ₂ wafer, SiN wafer, a glass substrate, a ceramic substrate, a plastic substrate is selected depending on the intended use. In particular, a substrate having metal wiring, for example, a semiconductor integrated circuit having wiring containing copper is preferable.

After the film is formed by a spin coating method or the like as described above, a heat treatment (drying step) for removing the solvent may be provided as necessary. In the drying step, optimum conditions are appropriately selected depending on the materials used, but it is preferable to dry the film under conditions that do not cause film hardening as described later.
The method of heat treatment is not particularly limited, however, generally used hot plate heating, heating method using a furnace, light irradiation heating using a xenon lamp by RTP (Rapid Thermal Processor), etc. are applied. Can do. A heating method using hot plate heating or furnace is preferable. Commercially available equipment can be preferably used as the hot plate, and the clean track series (manufactured by Tokyo Electron Ltd.), D-Spin series (manufactured by Dainippon Screen Mfg. Co., Ltd.), SS series or CS series (Tokyo Ohka Kogyo Co., Ltd.) Etc.) can be preferably used. As the furnace, α series (manufactured by Tokyo Electron Ltd.) and the like can be preferably used.

<Curing process>
Next, in the curing step, the film obtained in the film formation step is cured by irradiation with high energy rays or heat treatment. As a curing method, a method of irradiating a high energy beam (for example, an electron beam or an ultraviolet ray) is preferable in terms of shortening the curing time and mechanical strength.

In the case of curing by irradiating with a high energy beam, examples of the high energy beam include an electron beam, an ultraviolet ray, and an X-ray, and it is particularly preferable to use an electron beam.
The energy when an electron beam is used as the high energy beam is preferably 0 to 50 keV, more preferably 0 to 30 keV, and particularly preferably 0 to 20 keV. The total dose of the electron beam is preferably 0 to 5.0 μC / cm ² , more preferably 0 to 2.0 μC / cm ² , and particularly preferably 0 to 1.0 μC / cm ² . 0-450 degreeC is preferable, as for the substrate temperature at the time of irradiating an electron beam, 0-400 degreeC is more preferable, and 0-350 degreeC is especially preferable. The pressure is preferably 0 to 133 kPa, more preferably 0 to 60 kPa, and particularly preferably 0 to 20 kPa. From the viewpoint of preventing oxidation of the film of the present invention, it is preferable to use an inert atmosphere such as Ar, He, or nitrogen as the atmosphere around the substrate. Further, a gas such as oxygen, hydrocarbon, or ammonia may be added for the purpose of reaction with plasma, electromagnetic waves, or chemical species generated by interaction with an electron beam. The electron beam irradiation in the present invention may be performed a plurality of times. In this case, the electron beam irradiation conditions need not be the same each time, and may be performed under different conditions each time.

Ultraviolet rays may be used as the high energy rays. The irradiation wavelength region when using ultraviolet rays is preferably 190 to 400 nm, and the output is preferably 0.1 to 2,000 mWcm ⁻² immediately above the substrate. The substrate temperature at the time of ultraviolet irradiation is preferably 250 to 450 ° C, more preferably 250 to 400 ° C, and particularly preferably 250 to 350 ° C. From the viewpoint of preventing oxidation of the film of the present invention, the atmosphere around the substrate is preferably an inert atmosphere such as Ar, He, or nitrogen. Further, the pressure at that time is preferably 0 to 133 kPa.

Moreover, in this invention, you may make it harden | cure by heat processing instead of irradiating a high energy ray. For example, the polymerization reaction at the time of post-heating of the carbon triple bond remaining in the film formed from the insulating film forming composition can be used. The conditions for this post-heat treatment are preferably 100 to 450 ° C., more preferably 200 to 420 ° C., particularly preferably 350 to 400 ° C., preferably 1 minute to 2 hours, more preferably 10 minutes to 1.5 ° C. Time, particularly preferably in the range of 30 minutes to 1 hour. The post-heating treatment may be performed in several times. Further, this post-heating is particularly preferably performed in a nitrogen atmosphere in order to prevent thermal oxidation by oxygen.
In addition, you may perform heat processing and irradiation of the above-mentioned high energy ray simultaneously.

  In addition, as a preferable manufacturing method for manufacturing an insulating film using the above-described insulating film forming composition of the present invention, a film for forming a coating film by applying the above insulating film forming composition on a substrate is used. It is a manufacturing method comprising a forming step and a curing step of irradiating the coating film obtained in the film forming step with an electron beam or an ultraviolet ray high energy ray to cure.

<Insulating film>
The thickness of the insulating film obtained from the composition for forming an insulating film of the present invention is appropriately selected depending on the intended use, but is preferably 0.1 to 10 μm, more preferably 0.1 to 1 μm.

The dielectric constant of the insulating film obtained from the composition for forming an insulating film of the present invention varies depending on the material used, but when used as an insulating film, it is usually 4.0 or less at a measurement temperature of 25 ° C. Is more preferable, 1.5 to 3.5 is more preferable, and 1.8 to 3.0 is more preferable.
In addition, as a method for measuring the relative dielectric constant of the film obtained from the composition for forming an insulating film of the present invention, a mercury probe manufactured by Four Dimensions Inc. and an HP4285ALCR meter manufactured by Yokogawa Hewlett Packard Inc. were used at a measurement temperature of 25 ° C. It is preferable to calculate from the capacity value at 1 MHz.

The Young's modulus of the insulating film of the present invention varies depending on the material used, but is preferably 3.0 to 15.0 GPa, more preferably 5.0 to 15.0 GPa.
As a method for measuring the Young's modulus in the insulating film of the present invention, the measurement is performed using a nanoindenter SA2 manufactured by MTS.

  The film thickness reduction rate after heat treatment at 400 ° C. in air for 30 seconds in the insulating film of the present invention varies depending on the material used, but is preferably 0.0 to 15.0%, preferably 0.0 to 5. More preferably, it is 0%.

<Application>
The insulating film obtained by using the composition for forming an insulating film of the present invention can be suitably used as an interlayer insulating film for a semiconductor. That is, the insulating film obtained using the composition for forming an insulating film of the present invention can be suitably used for an electronic device. An electronic device means a wide range of electronic equipment including a semiconductor device and a magnetic recording head.
For example, when used as an interlayer insulating film for a semiconductor, in the wiring structure, there may be a barrier layer on the side surface of the wiring to prevent metal migration, and CMP (chemical In addition to the cap layer and interlayer adhesion layer that prevent peeling in mechanical and mechanical polishing, there may be an etching stopper layer, etc. Furthermore, the interlayer insulating film layer may be divided into multiple layers with other materials as required. Also good.

  The insulating film obtained by using the composition for forming an insulating film of the present invention can be etched for copper wiring or other purposes. Etching may be either wet etching or dry etching, but dry etching is preferred. For dry etching, either ammonia-based plasma or fluorocarbon-based plasma can be used as appropriate. These plasmas can use not only Ar but also gases such as oxygen, nitrogen, hydrogen, and helium. In addition, after the etching process, ashing can be performed for the purpose of removing the photoresist used in the process, and further, cleaning can be performed to remove a residue at the time of ashing.

  The insulating film obtained by using the composition for forming an insulating film of the present invention may be subjected to CMP treatment for flattening the copper plating portion after the copper wiring processing. As the CMP slurry (chemical solution), commercially available slurries (for example, manufactured by Fujimi Incorporated, manufactured by Rodel Nitta, manufactured by JSR, manufactured by Hitachi Chemical Co., Ltd., etc.) can be used as appropriate. Moreover, as a CMP apparatus, a commercially available apparatus (Applied Materials Co., Ltd., Ebara Manufacturing Co., Ltd. etc.) can be used suitably. Further, cleaning can be performed to remove slurry residues after CMP.

The insulating film obtained by using the composition for forming an insulating film of the present invention can be used for various purposes. For example, it is suitable as an insulating film in semiconductor devices such as LSI, system LSI, DRAM, SDRAM, RDRAM, and D-RDRAM, and electronic components such as multi-chip module multilayer wiring boards. Interlayer insulating film for semiconductor, etching stopper film, surface protection In addition to films, buffer coat films, LSI passivation films, alpha-ray blocking films, flexographic printing plate cover lay films, overcoat films, flexible copper clad cover coats, solder resist films, liquid crystal alignment films, etc. Can do.
Furthermore, as another application, the film of the present invention can be imparted with conductivity by doping with an electron donor or acceptor and used as a conductive film.

  EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited by these examples.

The following GPC measurements use Waters 2695 and Shodex GPC column KF-805L, measure the column temperature at 40 ° C., and use tetrahydrofuran as the elution solvent at a flow rate of 1 ml / min. The weight average molecular weight is prepared using standard polystyrene. Calculation was performed using the calibration curve.
In addition, by performing GPC-MALLS measurement using a multi-angle light scattering detector (Wyatt Technology, Wyatt DAWN EOS) under the above GPC conditions, the RMS radius-mole molecular weight logarithmic straight line (vertical axis: RMS radius, The slope of the horizontal axis: molar molecular weight was determined. A smaller value of this slope means that the degree of branching of the polymer is higher.

<Synthesis Example 1: Synthesis of polymer (A)>
A polymer (A) was synthesized according to the following scheme. In the scheme below, “*” in the repeating unit of the polymer (A) is bonded to “**” in the other repeating unit.

1,3,5-tribromoadamantane was synthesized according to the synthesis method described in the literature (J. Org. Chem., Vol. 69, 1010-1019 (2004)).
Next, in a 200 ml three-necked flask equipped with a nitrogen introduction tube and a stirrer, 4.81 g of 1,3,5-tribromoadamantane, 16.0 g of 1,3-dibromoadamantane, 5.31 g of benzene, and 100 g of dichlorobenzene were added. In addition, the raw materials were completely dissolved while stirring under a nitrogen stream. 2.20 g of iron (III) chloride was added and the reaction was stirred at room temperature for 90 minutes. The reaction solution was added to 500 mL of methanol, and the precipitated solid was filtered and washed with methanol. The obtained solid was added to a 300 ml three-necked flask equipped with a nitrogen introduction tube and a stirring device, and 46.8 g of tris (trimethylsilyl) silane, 1.54 g of 2,2′-azobis (isobutyronitrile), and 200 mL of toluene were added. In addition, the mixture was stirred at 80 ° C. for 3 hours with stirring under a nitrogen stream. The reaction solution was cooled to room temperature, added to 500 mL of methanol, and the precipitated solid was filtered. The obtained solid was redissolved in 100 mL of tetrahydrofuran and added dropwise to a mixed solution of 500 mL of methanol and 500 mL of tetrahydrofuran. The precipitated solid was filtered, washed with methanol, and dried under reduced pressure to obtain 8.13 g of polymer (A) having a weight average molecular weight of about 53,000. From the GPC-MALLS measurement, the slope of the RMS logarithm-mole molecular weight log-log line was calculated, and the value was 0.51 (nm / (g / mol)).

<Synthesis Example 2: Synthesis of Polymer (B)>
A polymer (B) was synthesized according to the following scheme. In the scheme below, “*” in the repeating unit of the polymer (B) is bonded to “**” in the other repeating unit.

1,3,5,7-tetrabromoadamantane was synthesized according to the synthesis method described in the literature (Org. Lett., Vol. 6, 1705-1708 (2004)).
In the same manner as in Synthesis Example 1 except that 13.2 g of 1,3,5,7-tetrabromoadamantane was used instead of 12.1 g of 1,3,5-tribromoadamantane in Synthesis Example 1, A union (B) was synthesized. The weight average molecular weight of the obtained polymer (B) was about 72,000. The slope of the RMS radius-mole molecular weight log-log line obtained from GPC-MALLS measurement was 0.47 (nm / (g / mol)).

<Synthesis Example 3: Synthesis of Polymer (C)>
A polymer (C) was synthesized according to the following scheme. In the scheme below, “*” in the repeating unit of the polymer (C) is bonded to “**” in the other repeating unit.

  In a 300 ml three-necked flask equipped with a nitrogen inlet tube and a stirrer, 3.60 g of 1,3,5-tribromoadamantane, 3.00 g of 1,3-dibromoadamantane, and 1,4-di-tert-butylbenzene 88 g and dichlorobenzene 180 g were added, and the raw materials were completely dissolved while stirring under a nitrogen stream. 0.66 g of iron (III) chloride was added and the reaction was stirred at room temperature for 10 minutes. The reaction solution was added to 500 mL of methanol, and the precipitated solid was filtered and washed with methanol. The obtained solid was added to a 100 ml three-necked flask equipped with a nitrogen introduction tube and a stirrer, 7.02 g of tris (trimethylsilyl) silane, 0.23 g of 2,2′-azobis (isobutyronitrile), and 60 mL of toluene. In addition, the mixture was stirred at 80 ° C. for 3 hours with stirring under a nitrogen stream. The reaction solution was cooled to room temperature, added to 500 mL of methanol, and the precipitated solid was filtered. The obtained solid was redissolved in 30 mL of tetrahydrofuran and added dropwise to a mixed solution of 150 mL of methanol and 150 mL of tetrahydrofuran. The precipitated solid was filtered, washed with methanol, and dried under reduced pressure to obtain 3.30 g of a polymer (C) having a weight average molecular weight of about 151,000. From the GPC-MALLS measurement, the slope of the RMS logarithm-mole molecular weight log-log line was calculated, and the value was 0.35 (nm / (g / mol)).

<Synthesis Example 4: Synthesis of Polymer (D)>
A polymer (D) was synthesized according to the following scheme. In the scheme below, “*” in the repeating unit of the polymer (D) is bonded to “**” in the other repeating unit.

1,6-Dibromodiamantane was synthesized according to the synthesis method described in the literature (J. Org. Chem., Vol. 39, 2995-3003 (1974)).
A polymer (D) was synthesized in the same manner as in Synthesis Example 3, except that 3.53 g of 1,6-dibromodiamantane was used instead of 3.00 g of 1,3-dibromoadamantane in Synthesis Example 3. . The weight average molecular weight of the obtained polymer (D) was about 122,000. The slope of the RMS radius-mole molecular weight log-log line obtained from GPC-MALLS measurement was 0.41 (nm / (g / mol)).

<Synthesis Example 5: Synthesis of Polymer (E)>
A polymer (E) was synthesized according to the following scheme. In the scheme below, “*” in the repeating unit of the polymer (E) is bonded to “**” in other repeating units.

1,4,9-tribromodiamantane was synthesized according to the synthesis method described in the literature (J. Org. Chem., Vol. 39, 2995-3003 (1974)).
In the same manner as in Synthesis Example 3, except that 3.53 g of 1,4,9-tribromodiamantane was used instead of 3.00 g of 1,3,5-tribromoadamantane in Synthesis Example 3, the polymer (E) was synthesized. The weight average molecular weight of the obtained polymer (E) was about 1440,000. The slope of the RMS logarithm-mole molecular weight log-log line obtained from GPC-MALLS measurement was 0.45 (nm / (g / mol)).

<Example 1>
A coating solution was prepared by completely dissolving 1.0 g of the polymer (A) in 9.0 g of cyclohexanone. This solution was filtered through a tetrafluoroethylene filter having a pore diameter of 0.1 μm, and then spin-coated on a 4-inch bare silicon wafer having a substrate resistance of 7 Ω / cm using a spin coater. The coated film was baked at 110 ° C. for 60 seconds and then at 200 ° C. for 60 seconds. Furthermore, as a result of baking (furnace cure) for 1 hour in a 400 ° C. clean oven purged with nitrogen, a uniform film having a film thickness of 0.5 μm was obtained.
The relative dielectric constant of the film (measurement temperature: 25 ° C., and so on) was calculated from the capacitance value at 1 MHz using a mercury probe manufactured by Four Dimensions and an HP4285ALCR meter manufactured by Yokogawa Hewlett-Packard Co. 2.35. Met.
The appearance of the obtained insulating film was observed with a pocket micro loupe (50 times) manufactured by Peak Co., but no crack was observed on the surface of the coating film, and the surface condition was good. In addition, when observing the film surface shape in an area of 1 cm 2 with an optical microscope, when the color unevenness is observed, the evaluation is “poor surface state”, and when no color unevenness is observed at all, the surface condition is good. did.
Moreover, it was 8.5 GPa when the Young's modulus of the insulating film obtained using MTS nanoindenter SA2 was measured.
As evaluation of heat resistance, the obtained film was heated in air at 400 ° C. for 30 seconds, and the reduction rate of the film thickness was measured and found to be 0.1%.

<Example 2>
A coating solution was prepared by completely dissolving 1.0 g of the polymer (A) in 9.0 g of cyclohexanone. This solution was filtered through a tetrafluoroethylene filter having a pore diameter of 0.1 μm, and then spin-coated on a 4-inch bare silicon wafer having a substrate resistance of 7 Ω / cm using a spin coater. The coated film was baked at 110 ° C. for 60 seconds and then at 200 ° C. for 60 seconds. The obtained coating film was cured for 50 seconds while irradiating an electron beam with an acceleration voltage of 13 keV on a 350 ° C. hot plate placed in a vacuum chamber adjusted to a vacuum degree of 10 Torr in a helium gas atmosphere. A uniform film having no irregularities of 0.5 μm was obtained.
The relative dielectric constant (measurement temperature: 25 ° C.) of the film was calculated from the capacitance value at 1 MHz by using a mercury probe manufactured by Four Dimensions and an HP4285ALCR meter manufactured by Yokogawa Hewlett-Packard Co., and found to be 2.36.
The appearance of the obtained insulating film was observed with a pocket micro loupe (50 times) manufactured by Peak Co., but no crack was observed on the surface of the coating film, and the surface condition was good.
Moreover, it was 11.5 GPa when the Young's modulus of the insulating film obtained using MTS nanoindenter SA2 was measured.
As evaluation of heat resistance, the obtained film was heated in air at 400 ° C. for 30 seconds, and the reduction rate of the film thickness was measured and found to be 0.3%.

<Examples 3 to 6>
For the polymer (B), the polymer (C), the polymer (D), and the polymer (E), the coating solution was prepared, applied, and the coating film was baked in the same manner as in Example 2. Table 1 shows the evaluation results of the obtained insulating film.

<Comparative Example 1>
A coating solution was prepared according to the preparation method of Invention Example 4 described in JP-T-2005-522528, and a film was formed in the same manner as in Example 1. The slope of the RMS radius-mole molecular weight logarithmic line obtained from GPC-MALLS measurement of the polymer used in Comparative Example 1 was 0.68 (nm / (g / mol)).
The relative dielectric constant (measurement temperature: 25 ° C.) of the film was calculated from the capacitance value at 1 MHz using a mercury probe manufactured by Four Dimensions and a HP4285ALCR meter manufactured by Yokogawa Hewlett-Packard, and found to be 2.79.
The appearance of the obtained insulating film was observed with a pocket micro loupe (50 times) manufactured by Peak Co., but the surface state of the obtained insulating film was bad.
Moreover, it was 5.3 GPa when the Young's modulus of the insulating film obtained using Nanoindenter SA2 of MTS was measured.
As an evaluation of heat resistance, the obtained film was heated in air at 400 ° C. for 30 seconds, and the reduction rate of the film thickness was measured and found to be 7.2%.

  It was confirmed that the insulating film formed using the composition for forming an insulating film of the present invention is excellent in low dielectric constant, heat resistance, mechanical strength and film surface shape.

Claims (8)

The composition for insulating film formation containing the polymer containing the repeating unit which has a branched structure represented by General formula (1).

(In general formula (1), X represents a cage structure, Y represents an aromatic hydrocarbon group, R ¹ represents an aromatic hydrocarbon group, and R ² represents a substituent. “*”. Represents a bonding position, a represents an integer of 0 to 18, b represents an integer of 0 to 6, c represents an integer of 2 to 7, and d represents an integer of 1 to 3.)   The polymer is measured using GPC (Gel Permeation Chromatography) -MALLS (Multi Angle Light Scattering Detector) to determine the RMS radius (nm) and molar molecular weight (g / mol) as the RMS radius ( (nm) is plotted on a log-log graph with the vertical axis and the molar molecular weight (g / mol) on the horizontal axis, and the slope of the obtained straight line is 0.25 to 0.60 (nm / (g / mol)). The composition for forming an insulating film according to claim 1, which is a polymer having a degree of branching.   The composition for forming an insulating film according to claim 1 or 2, wherein the aromatic hydrocarbon group represented by Y in the general formula (1) is a benzene ring group.   The composition for forming an insulating film according to claim 1, wherein the cage structure in the general formula (1) is adamantane, biadamantane, or diamantane. The polymer is at least one selected from the group consisting of a repeating unit represented by the general formula (2), a repeating unit represented by the general formula (3), and a repeating unit represented by the general formula (4). The composition for forming an insulating film according to claim 1, which is a polymer having

(In General Formula (2) to General Formula (4), R ¹ represents an aromatic hydrocarbon group. R ² represents a substituent. “*” Represents a bonding position. E represents 0 to 6. An integer, f represents an integer of 0 to 4, g represents an integer of 2 to 7, and h represents an integer of 1 to 2.) A film forming step of applying a composition for forming an insulating film according to any one of claims 1 to 5 on a substrate to form a coating film,
A method for producing an insulating film, comprising: a curing step of irradiating the coating film with an electron beam or an ultraviolet ray high energy ray to cure.   The insulating film formed using the composition for insulating film formation in any one of Claims 1-5.   An electronic device having the insulating film according to claim 7.