JP2022055652A - Curable resin composition for low dielectric constant material, and cured product and low dielectric constant material obtained from the resin composition - Google Patents

Abstract

To provide a curable resin composition for a low dielectric constant material from which a cured product having excellent film-forming property, and low dielectric characteristics and transparency is obtained.SOLUTION: A curable resin composition for a low dielectric constant material contains a polymer containing at least one structural unit a represented by the following general formula (1), and at least one structural unit b represented by the following general formula (2).SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition for a low dielectric constant material, a cured product obtained from the resin composition, and a low dielectric constant material.

So far, various developments have been made in cyclic olefin polymers. As this kind of technique, for example, the technique described in Patent Document 1 is known. Patent Document 1 describes that a resin composition obtained by kneading a cyclic olefin polymer having a glass transition temperature of 101 to 160 ° C. and another elastomer is used as a molding material (Patent Document 1). Claim 1, paragraph 0042, etc.).

Japanese Unexamined Patent Publication No. 2013-231171

However, in the resin composition described in Patent Document 1, there is room for improvement in terms of low dielectric property.
As a result of examination, the present inventor has found that by appropriately selecting the structure of the structural unit of the cyclic olefin polymer, the film forming property is excellent, and the obtained cured product is excellent in low dielectric property and transparency. The invention was completed.
According to the present invention

（一般式（１）中、ｍは０、１または２である。
一般式（２）中、Ｘは炭素数３～２０の直鎖または分岐のアルキル基、炭素数３～１０のシクロアルキル基、またはアリール基を示す。ｎは０、１または２である。） Curing for low dielectric constant materials containing a polymer containing at least one structural unit a represented by the following general formula (1) and at least one structural unit b represented by the following general formula (2). A sex resin composition can be provided.

(In the general formula (1), m is 0, 1 or 2.
In the general formula (2), X represents a linear or branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group. n is 0, 1 or 2. )

According to the present invention, it is possible to provide a cured product obtained by curing the curable resin composition for a low dielectric constant material.
According to the present invention, it is possible to provide a low dielectric constant material made of the cured product.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a curable resin composition for a low dielectric constant material, which can obtain a cured product having excellent film forming property and further excellent low dielectric constant and transparency.

Hereinafter, the present invention will be described based on the embodiments. In addition, "-" represents "greater than or equal to" to "less than or equal to" unless otherwise specified.
The curable resin composition for a low dielectric constant material of the present embodiment (hereinafter, may be referred to as a curable resin composition) contains a polymer (A).

[Polymer (A)]
The polymer (A) of the present embodiment contains at least one structural unit a represented by the following general formula (1) and at least one structural unit b represented by the following general formula (2).

In the general formula (1), m is 0, 1 or 2, preferably 0 or 1.
In the general formula (2), X represents a linear or branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group, preferably a linear or branched alkyl group having 3 to 20 carbon atoms. It is a branched alkyl group. A plurality of Xs present in the polymer (A) may be the same or different.

Linear or branched alkyl groups having 3 to 20 carbon atoms include propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, octadecyl group and isopropyl group. Examples thereof include a group, an isobutyl group, a sec-butyl group, a t-butyl group, a 1-ethylpentyl group, a 2-ethylhexyl group and the like.

Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like. Examples of the polycyclic cyclic alkyl group include an adamantyl group, a norbornyl group, a bornyl group, a phenyl group, a decahydronaphthyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a camphoroyl group, a dicyclohexyl group and a pinenyl group. Can be mentioned.

Examples of the aryl group include a phenyl group, a naphthyl group, an anthrasenyl group, a phenanthryl group, a pyrenyl group, a peryleneyl group, a fluoranthenyl group, a fluoranthenyl group and the like.
n is 0, 1 or 2, preferably 0 or 1.

The curable resin composition for a low dielectric constant material of the present embodiment is lightly or heated by containing a polymer (A) containing at least one structural unit a and at least one structural unit b. Alternatively, it can be cured by using light and heating in combination, and a cured product having excellent film forming property, low dielectric constant and transparency can be obtained. The cured product is also excellent in heat resistance.

In the present embodiment, the polymer (A) can further contain at least one structural unit c represented by the following general formula (3) from the viewpoint of the effect of the present invention.

In the general formula (3), R independently represent an alkoxy group having 1 to 3 carbon atoms or an alkyl group having 1 to 3 carbon atoms, and at least two Rs are alkoxy groups having 1 to 3 carbon atoms. A plurality of Rs present in the polymer (A) may be the same or different from each other.
p indicates an integer from 0 to 3.

The alkoxy group having 1 to 3 carbon atoms is a methoxy group, an ethoxy group, and a propoxy group, and the alkyl group having 1 to 3 carbon atoms is a methyl group, an ethyl group, and a propyl group.
l is 0, 1 or 2, preferably 0 or 1.

Since the curable resin composition of the present embodiment is used for a dielectric constant material, it is preferable that the polymer (A) does not contain a structural unit derived from maleic acid or maleimide.
Furthermore, the polymer (A) does not contain polar functional groups such as a carboxyl group, an epoxy group, an ester group and an amino group.

In order to cure the polymer (A), it is preferable that the polymer (A) contains a structural unit derived from maleic acid or maleimide, or the polymer (A) contains a polar functional group in the structure, but the obtained cured product is obtained. Since the dielectric constant is improved, there is a trade-off relationship between curability and low dielectric constant. The polymer (A) containing the structural unit a and the structural unit b of the present embodiment, and optionally the structural unit c, is a cured product which does not contain a structural unit or a polar functional group derived from maleic acid or maleimide. Since it can be obtained and does not contain a polar functional group, the cured product has excellent low dielectric constant and excellent transparency.

From the viewpoint of the effect of the present invention, the lower limit of the content of the polymer (A) is preferably 50% by mass or more, more preferably 70% by mass or more, based on 100% by mass of the curable resin composition of the present embodiment. More preferably, it is 90% by mass or more. Thereby, the heat resistance of the resin material can be further improved. On the other hand, the upper limit of the content of the polymer (A) may be, for example, preferably 100% by mass or less, more preferably 99% by mass or less, and further preferably 95% by mass or less. This makes it possible to balance various characteristics.

The lower limit of the glass transition temperature (Tg) of the polymer (A) is, for example, 80 ° C. or higher, preferably 100 ° C. or higher, and more preferably 120 ° C. or higher. This makes it possible to further improve the thermal characteristics of the resin material. On the other hand, the upper limit of the glass transition temperature of the polymer (A) is not particularly limited, but may be, for example, 400 ° C. or lower, 350 ° C. or lower, 290 ° C. or lower. This makes it possible to improve the coating film property of the resin varnish and the moldability of the resin material.

Further, from the viewpoint of the effect of the present invention, the Mw (weight average molecular weight) of the polymer (A) is, for example, 2 × 10 ³ to 1.0 × 10 ⁵ , preferably 3.0 × 10 ³ to 8.0 ×. It can be 10 ⁴ , more preferably 4.0 × 10 ³ to 7.0 × 10 ⁴ , and even more preferably 5.0 × 10 ³ to 5.0 × 10 ⁴ .

The Mw (weight average molecular weight) / Mn (number average molecular weight) of the polymer (A) is, for example, 1.0 to 6.0, preferably 1.2 to 5.0, and more preferably 1.5 to 4. It can be 0, more preferably 1.8 to 3.0. Mw / Mn is a degree of dispersion indicating the width of the molecular weight distribution.

The weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) are obtained from the calibration curve of standard polystyrene (PS) obtained by, for example, GPC (Gel Permeation Chromatography) measurement. Use the converted value. The measurement conditions are as follows, for example.

Tosoh gel permeation chromatography device HLC-8320GPC
Column: Tosoh TSK-GEL Supermultipore HZ-M
Detector: RI detector for liquid chromatogram Measurement temperature: 40 ° C
Solvent: THF
Sample concentration: 2.0 mg / ml

Further, the low molecular weight component weight in the polymer (A) is calculated from the ratio of the total area of the components corresponding to the molecular weight of 1000 or less to the total area of the molecular weight distribution, based on the data on the molecular weight obtained by, for example, GPC measurement. To.

[Method for synthesizing polymer (A)]
The polymer (A) of the present embodiment can be synthesized, for example, as follows.
(Polymerization step (treatment S1))
First, for example, a predetermined norbornene-based monomer is prepared as the monomer.
Then, the prepared monomer is addition-polymerized to obtain a polymer. For example, addition polymerization is carried out by coordination polymerization.

In the present embodiment, solution polymerization can be carried out by dissolving the above-mentioned monomer and the organometallic catalyst in a solvent and then heating the mixture for a predetermined time. At this time, the heating temperature can be, for example, 60 ° C. to 200 ° C., preferably 70 ° C. to 150 ° C., and more preferably 80 ° C. to 120 ° C. In the present embodiment, the yield of the polymer (A) can be improved by raising the heating temperature higher than before.

The heating time can be, for example, 0.5 hours to 72 hours. It is more preferable to perform solution polymerization after removing dissolved oxygen in the solvent by nitrogen bubbling.

In addition, a molecular weight modifier or a chain transfer agent can be used as needed. Examples of the chain transfer agent include alkylsilane compounds such as trimethylsilane, triethylsilane, and tributylsilane. These chain transfer agents may be used alone or in combination of two or more.

Examples of the solvent used in the above polymerization reaction include esters such as methyl ethyl ketone (MEK), propylene glycol monomethyl ether, diethyl ether, tetrahydrofuran (THF), toluene, ethyl acetate and butyl acetate, methyl alcohol, ethyl alcohol and isopropyl alcohol. One or more of the alcohols in the above can be used.

The organometallic catalyst is not particularly selected as long as the addition polymerization proceeds, but for example, a phosphine-based or diimine-based ligand may be coordinated with the palladium complex and the nickel complex, and a counter anion may be used. good. One or more of these can be used.

Examples of the palladium complex include (acetato-κ0) (acetohydrate) bis [tris (1-methylethyl) phosphine] palladium (I) tetrakis (2,3,4,5,6-pentafluorophenyl) borate, π-. Allylpalladium complex, such as allylpalladium chloride dimer,
Organic carboxylates of palladium, such as acetate of palladium, propionate, maleate, naphthoate, etc.
Palladium organic carboxylic acid complexes such as palladium acetate triphenylphosphine complex, palladium acetate tri (m-tolyl) phosphine complex, palladium acetate tricyclohexylphosphine complex,
Dibutyl phosphite of palladium, organic sulfonate of palladium such as p-toluenesulfonate,
Palladium β-diketone compounds such as bis (acetylacetonate) palladium, bis (hexafluoroacetylacetonate) palladium, bis (ethylacetacetate) palladium, and bis (phenylacetacetate) palladium,
Examples include halide complexes of palladium such as dichlorobis (triphenylphosphine) palladium, bis [tri (m-tolylphosphine)] palladium, dibromobis [tri (m-tolylphosphine)] palladium, and acetnyltriphenylphosphonium complex. Be done.

Examples of the phosphine ligand include triphenylphosphine, dicyclohexylphenylphosphine, cyclohexyldiphenylphosphine, and tricyclohexylphosphine.

Examples of the counter anion include triphenylcarbenium tetrakis (pentafluorophenyl) borate, triphenylcarbenium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate, and triphenylcarbenium tetrakis (2,4). 6-Trifluorophenyl) borate, triphenylcarbenium tetraphenyl borate, tributylammonium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, N, N-diethylanilinium tetrakis ( Examples thereof include pentafluorophenyl) borate, N, N-diphenylanilinium tetrakis (pentafluorophenyl) borate, and lithium tetrakis (pentafluorophenyl) borate.

The amount of the organometallic catalyst can be 300 ppm to 5000 ppm, preferably 1000 ppm to 3500 ppm, more preferably 1500 ppm to 2500 ppm with respect to the norbornene-based monomer. Thereby, the yield of the polymer (A) can be improved.

When the vinyl norbornene monomer, which is the raw material compound of the structural unit a represented by the general formula (1), is polymerized using the organometallic catalyst, the conventional reaction is difficult to proceed and the yield is low. In the present embodiment, even when the organometallic catalyst is used, the heating temperature is set to a higher temperature than before as described above, and more preferably, the amount of the organometallic catalyst is set within a predetermined range as described above. As a result, even when the organometallic catalyst is used, the polymerization reaction of the vinyl norbornene monomer proceeds and the yield can be improved.

(Washing step (treatment S2))
The reaction solution containing the obtained polymer is added to an alcohol such as hexane or methanol to precipitate the polymer (A). Next, the polymer (A) is collected by filtration, washed with, for example, an alcohol such as hexane or methanol, and then dried.
In the present embodiment, the polymer (A) can be synthesized, for example, in this way.
According to the production method of the present embodiment, the polymer (A) can be obtained in a high yield of 70% or more.

[Curing catalyst (B)]
The curable resin composition for a low dielectric constant material of the present embodiment may further contain a curing catalyst. As the curing catalyst, a known curing catalyst can be used as long as the effect of the present invention can be exhibited.

As the curing catalyst (B), a known curing catalyst that promotes curing by heat or a known curing catalyst that promotes curing by light can be used to the extent that the effect of the present invention can be exhibited. Examples of the curing catalyst (B) include a thermal acid generator, a photoacid generator, and a photoradical generator.
If a predetermined amount of the catalyst used in the above synthesis method remains in the polymer (A), the polymer (A) is cured by heating, so that the curing catalyst is not essential.

Examples of the thermoacid generator include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, boron trifluoride amine complexes and the like. As the thermal acid generator, one or more of these may be contained.
The curable resin composition of the present embodiment contains, preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 2 parts by mass or more and 15 parts by mass or less of a thermal acid generator with respect to 100 parts by mass of the polymer (A). Can be done.

Examples of the photoacid generator include onium salt compounds. Specifically, iodonium salts such as diazonium salt and diaryliodonium salt, sulfonium salts such as triarylsulfonium salt, triarylvirylium salt, benzylpyridinium thiocyanate, dialkylphenacil sulfonium salt, dialkylhydroxyphenylphosphonium salt and the like. Examples thereof include a cationic photopolymerization initiator.

The curable resin composition of the present embodiment contains, preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 2 parts by mass or more and 15 parts by mass or less of a photoacid generator with respect to 100 parts by mass of the polymer (A). Can be done.
A photoacid generator and a thermoacid generator may be used in combination.

Specific examples of the photoradical generator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, and 2-hydroxy-2-methyl-1-phenyl. Propane-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4- [4- (2) -Hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropane-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1 -Alkylphenyl compounds such as butanone;
Benzophenone compounds such as benzophenone, 4,4'-bis (dimethylamino) benzophenone, 2-carboxybenzophenone; benzoin compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutylate;
Thioxanthone compounds such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone;
2- (4-Methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4) -Halomethylated triazine compounds such as ethoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine and 2- (4-ethoxycarboquinylnaphthyl) -4,6-bis (trichloromethyl) -s-triazine ;
2-Trichloromethyl-5- (2'-benzofuryl) -1,3,4-oxadiazole, 2-trichloromethyl-5-[β- (2'-benzofuryl) vinyl] -1,3,4-oxa Halomethylated oxadiazole-based compounds such as diazole, 4-oxadiazole, 2-trichloromethyl-5-furyl-1,3,4-oxadiazole;
2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-Tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5,5'-tetraphenyl-1, 2'-Bimidazole-based compounds such as biimidazole;
1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-3 Oxime ester compounds such as-, 1- (O-acetyloxime);
Titanocene compounds such as bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium;
Benzoic acid ester compounds such as p-dimethylaminobenzoic acid and p-diethylaminobenzoic acid;
Acridine compounds such as 9-phenylacridine; and the like can be mentioned.

The curable resin composition of the present embodiment contains, preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 2 parts by mass or more and 15 parts by mass or less of a photoradical generator with respect to 100 parts by mass of the polymer (A). Can be done.

Further, by using a photosensitizer or a photoradical polymerization accelerator together with the photoradical generator, the sensitivity and the degree of cross-linking can be further improved. For example, dye compounds such as xanthene dyes and coumarin dyes, dialkylaminobenzene compounds such as ethyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-dimethylaminobenzoate, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole and the like. Examples include mercapto-based hydrogen donors.

(Other ingredients)
The curable resin composition of the present embodiment has a filler, a resin other than the polymer (A), a cross-linking agent, an acid generator, a heat resistance improver, a developing aid, a plasticizer, and a polymerization agent, depending on the purpose and required characteristics of each application. Banners, UV absorbers, Antioxidants, Matters, Defoamers, Leveling Agents, Antistatic Agents, Dispersants, Slip Agents, Surface Modifiers, Shaking Agents, Shaking Aids, Surfactants, Other components such as silane-based, aluminum-based, and titanium-based coupling agents, polyhydric phenol compounds, and organic solvents may be blended.

[Curable resin composition for low dielectric constant materials]
The curable resin composition for a low dielectric constant material of the present embodiment is prepared by mixing the polymer (A), the curing catalyst (B) added as needed, and the above-mentioned other components. Can be done.

The curable resin composition of the present embodiment may be a polymer solution in which the polymer is dissolved in a solvent. In this polymer solution, at least a part of the polymer may be dissolved at a liquid temperature of 25 ° C., but it is preferable that all the polymers are dissolved.

Here, the solid content concentration may be the mass ratio (mass%) of the polymer dissolved in the solvent to 100% by mass of the resin varnish at a liquid temperature of 25 ° C. The content of the polymer may be expressed in terms of solid content concentration.

Further, the polymer contained in the resin varnish contains the polymer (A). The content ratio of the polymer (A) in the polymer can be appropriately adjusted as long as the heat resistance according to the application can be obtained. Specifically, the content of the polymer (A) may be, for example, 10% by mass or more, 50% by mass, or 90% by mass or more with respect to 100% by mass of the polymer contained in the resin varnish. It may be 100% by mass. As the other polymer, various copolymers may be used depending on the purpose.

The lower limit of the polymer content in the resin varnish is, for example, 5% by mass or more, preferably 7% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, based on 100% by mass of the resin varnish. Is. On the other hand, the upper limit of the polymer content in the resin varnish is, for example, 50% by mass or less, preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 25% by mass, based on 100% by mass of the resin varnish. % Or less. Within such a numerical range, the handling property of the resin varnish can be improved, and a resin material having excellent heat resistance can be realized.

The main component of the non-volatile component in the resin varnish may be composed of the polymer. That is, the content of the polymer is, for example, 90% by mass or more, preferably 95% by mass or more, and more preferably 100% by mass with respect to 100% by mass of the non-volatile content.
Here, the non-volatile component refers to the balance obtained by removing volatile components such as a solvent from the resin varnish.

The curable resin composition containing the polymer (A) of the present embodiment is applied to a substrate, dried at 120 ° C. for 5 minutes, and the obtained 20 μm resin film A is heated under the conditions of (1) or (2) below. It is preferable that the residual film ratio after this is satisfied with the following numerical values.
(1) The residual film ratio calculated by the following formula from the film thickness of the resin film B after heating the resin film A (20 μm) at 150 ° C. for 1 hour and then immersing it in hexane for 2 minutes is preferably 50% or more. It is 60% or more. The upper limit is not particularly limited, but is 80% or less, preferably 70% or less.
(2) The residual film ratio calculated by the following formula from the film thickness of the resin film B'after heating the resin film A (20 μm) at 180 ° C. for 30 minutes and then immersing it in hexane for 2 minutes is preferable. Is 80% or more. The upper limit is not particularly limited, but is 100% or less, preferably 98% or less.
(formula)
Remaining film ratio (%) = {(Film thickness (μm) of resin film B (or B') immersed in hexane after heating) / (Film thickness of resin film A after drying: 20 μm)} × 100

The curable resin composition for a low dielectric constant material of the present embodiment contains a polymer (A) obtained by polymerizing a predetermined norbornene-based monomer, but the resin film has any of the dissolution characteristics (1) and (2). Since the above conditions are also satisfied, the film forming property is excellent, and there are a B stage state and a C stage state. Therefore, as will be described later, the interlayer insulating film constituting the multilayer wiring structure of the semiconductor element, the build-up layer or the core layer constituting the circuit board, etc. are excellent in manufacturing stability and can be suitably used for these semiconductor applications. ..
The residual film ratio ((film thickness after immersion / film thickness before immersion) × 100) of the 20 μm resin film A obtained by drying at 120 ° C. for 5 minutes after being immersed in hexane for 2 minutes is 0% or more and 20. % Or less, preferably 5% or more and 15% or less. By satisfying the residual film ratio, the handleability of the curable resin composition for low dielectric constant materials is excellent.

[Use]
The curable resin composition of the present embodiment can be obtained as a cured product by removing the organic solvent by drying or the like, if necessary, and curing by light or heating, or by using light and heating in combination.

Thermosetting can be performed in an atmosphere, a nitrogen atmosphere, a vacuum, or the like. When transparency is required for the obtained cured product, it is preferable to carry out the process in a nitrogen atmosphere or in a vacuum, or it is preferable to use an antioxidant in combination.

The relative permittivity of the cured product at a frequency of 1 MHz can be preferably 2.6 or less, preferably 2.4 or less. This makes it possible to apply the cured product to low dielectric constant materials.
Further, the dielectric loss tangent (tan δ) of the cured product at a frequency of 1 MHz is preferably 0.005 or less, and more preferably 0.003 or less. This makes it possible to further improve the dielectric properties of the cured product.

This low dielectric constant material can be used for various purposes, and can be applied to, for example, applications that require heat resistance and use in a film form. Further, the low dielectric constant material can provide a resin film (low dielectric constant film) having excellent transparency.

Specific applications include applications for printed circuit boards and applications for forming resin films such as permanent films.
The printed circuit board can be obtained by impregnating a low-dielectric cloth such as glass cloth with a curable resin composition and curing the printed circuit board.
On the other hand, as the resin film, an interlayer film, a surface protective film, a dam material and the like are known as typical examples, but the resin film is not limited thereto. As will be described later, the resin film is used in electronic components and devices such as semiconductor devices and in the manufacturing process thereof.

The interlayer film refers to an insulating film provided in the multilayer structure, and the type thereof is not particularly limited. Examples of the interlayer film include those used in semiconductor applications such as an interlayer insulating film constituting a multilayer wiring structure of a semiconductor element, a build-up layer constituting a circuit board, or a core layer. The interlayer film may be, for example, a flattening film covering a thin film transistor in a display device, a liquid crystal alignment film, a protrusion provided on a color filter substrate of an MVA type liquid crystal display device, or a partition wall for forming a cathode of an organic EL element. The one used in the display element application of is also mentioned.

The surface protective film refers to a film formed on the surface of an electronic component, an electronic device, or a substrate on which these are formed, and for protecting the surface. Examples of such a surface protective film include a passivation film provided on a semiconductor element, a bump protective film or a buffer coat layer, or a cover coat provided on a flexible substrate, which is made of an organic material or an inorganic material. It has excellent adhesion to the substrate.
Further, the dam material is a spacer used for forming a hollow portion for arranging an optical element or the like on a substrate.

The curable resin composition of the present embodiment can be used to form such a permanent film. That is, a resin film (low dielectric constant film) made of a curable resin composition can be applied to a permanent film. A resin film (low dielectric constant film) can also be used as a part of the permanent film. For example, a curable resin composition can be applied and cured on the surface of a permanent film made of a conventionally known material, and coated with a resin film (low dielectric constant film).

In the present embodiment, the thickness of the resin film can be appropriately adjusted according to the intended use. The lower limit of the thickness of the resin film may be, for example, 10 μm or more, 15 μm or more, or 20 μm or more. On the other hand, the upper limit of the thickness of the resin film may be, for example, 100 μm or less, 70 μm or less, 60 μm or less, and 30 μm or less.
Curable resin composition of the present embodiment By using the curable resin composition, cracks do not occur even in a resin film having a thickness within the above range.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted as long as the effects of the present invention are not impaired.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

(Preparation of catalyst solution 1)
0.274 g (0.00075 mol) of allylpalladium (II) chloride (dimer), 0.403 g (0.0015 mol) of diphenylcyclohexylphosphine, and 200 g of dehydrated toluene are placed in a nitrogen-conditioned glass container from which water has been removed in advance. Add, stir at room temperature for 1 hour to dissolve, then add 1.502 g (0.0019 mol) of N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate and stir for another 30 minutes to nitrogen. The solution was filtered with an under-air filter to give the catalyst solution 1.

<Polymer synthesis>
(Synthesis Example 1: Copolymer 1)
In an appropriately sized reaction vessel equipped with a stirrer and a cooling tube, 5-butylbicyclo [2.2.1] hepta-2-ene (337.8 g, 2.25 mol), 5-vinylbicyclo [2.2]. .1] Hepta-2-ene (180 g, 1.50 mol) was dissolved in 500 g of dehydrated toluene. After removing the dissolved oxygen in the system by nitrogen bubbling with respect to this solution, when the temperature reaches 100 ° C. while stirring, the catalyst solution 1 prepared in advance is added under a nitrogen stream and the temperature is 100 ° C. for 3 hours. After carrying out the reaction while maintaining the internal temperature under the conditions of the above, 2 g of triethylsilane was added. As a result, a copolymer 1 having the following structural units was obtained.
Then, the above-mentioned solution cooled to room temperature was reprecipitated with a large amount of methyl ethyl ketone, the precipitate was collected by filtration, the sample was washed with a large amount of methyl ethyl ketone, and the polymer was separated by solid-liquid separation. It was taken out and dried in a vacuum dryer to obtain 373 g of a white powder polymer.
The weight average molecular weight (Mw) of the copolymer 1 thus obtained was 15,000, and the dispersity (Mw / Mn) was 2.1.

(Synthesis Example 2: Copolymer 2)
5-Butylbicyclo [2.2.1] hepta-2-ene (675.6 g, 4.5 mol), 5-vinylbicyclo [2.2] in an appropriately sized reaction vessel equipped with a stirrer and a condenser. .1] Dehydration of hepta-2-ene (360 g, 3.0 mol), [bicyclo [2.2.1] hepta-5-ene-2-yl] triethoxysilane (70 g, 0.29 mol) 1,000 g It was dissolved in toluene. After removing the dissolved oxygen in the system by nitrogen bubbling with respect to this solution, when the temperature reaches 90 ° C while stirring, the catalyst solution 1 prepared in advance is added under a nitrogen stream and the temperature is 90 ° C for 5 hours. After carrying out the reaction while maintaining the internal temperature under the conditions of the above, 2 g of triethylsilane was added. As a result, a copolymer 2 having the following structural units was obtained. Then, the above-mentioned solution cooled to room temperature was reprecipitated with a large amount of methyl ethyl ketone, the precipitate was collected by filtration, the sample was washed with a large amount of methyl ethyl ketone, and the polymer was separated by solid-liquid separation. It was taken out and dried in a vacuum dryer to obtain 890 g of a white powder polymer.
The weight average molecular weight (Mw) of the copolymer 2 thus obtained was 24,000, and the dispersity (Mw / Mn) was 2.5.

(Synthetic Comparative Example 1: Homopolymer 1)
5-Butylbicyclo [2.2.1] hepta-2-ene (2,252 g, 15.0 mol), triethylsilane (1.0 g, 0) in an appropriately sized reaction vessel equipped with a stirrer and a cooling tube. .009 mol) was weighed and dissolved in 8,000 g of dehydrated toluene. After removing the dissolved oxygen in the system by nitrogen bubbling with respect to this solution, when the temperature reaches 60 ° C. while stirring, the catalyst solution 1 prepared in advance is added under a nitrogen stream and the temperature is 60 ° C. for 4 hours. After carrying out the reaction while maintaining the internal temperature under the conditions of the above, 2 g of triethylsilane was added. As a result, a homopolymer 1 having the following structural units was obtained. Next, the above solution cooled to room temperature was reprecipitated with a large amount of methyl ethyl ketone, the precipitate was collected by filtration, the sample was washed with a large amount of methyl ethyl ketone, and homopolymer was separated by solid-liquid separation. Was taken out and dried in a vacuum dryer to obtain 1,800 g of white powder homopolymer.
The weight average molecular weight (Mw) of the homopolymer 1 thus obtained was 450,000, and the dispersity (Mw / Mn) was 4.2.

(Synthetic Comparative Example 2: Homopolymer 2)
In a reaction vessel of appropriate size equipped with a stirrer and a cooling tube, 5-vinylbicyclo [2.2.1] hepta-2-ene (500 g, 4.17 mol) is weighed and dissolved in 500 g of dehydrated toluene. rice field. After removing the dissolved oxygen in the system by nitrogen bubbling with respect to this solution, when the temperature reaches 100 ° C. with stirring, the catalyst solution 1 prepared in advance is added under a nitrogen stream and the temperature is 100 ° C. for 8 hours. After carrying out the reaction while maintaining the internal temperature under the conditions of the above, 2 g of triethylsilane was added. As a result, a homopolymer 2 having the following structural units was obtained. Next, the above solution cooled to room temperature was reprecipitated with a large amount of methyl ethyl ketone, the precipitate was collected by filtration, the sample was washed with a large amount of methyl ethyl ketone, and homopolymer was separated by solid-liquid separation. Was taken out and dried in a vacuum dryer to obtain 280 g of white powder homopolymer.
The weight average molecular weight (Mw) of the homopolymer 2 thus obtained was 7,000, and the dispersity (Mw / Mn) was 2.2.

For the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the obtained polymer, polystyrene-equivalent values obtained from the calibration curve of standard polystyrene (PS) obtained by GPC measurement were used. The measurement conditions are as follows.
Gel Permeation Chromatography Equipment HLC-8320GPC manufactured by Tosoh Corporation
Column: TSK-GEL Supermultipore HZ-M manufactured by Tosoh Corporation
Detector: RI detector for liquid chromatogram Measurement temperature: 40 ° C
Solvent: THF
Sample concentration: 2.0 mg / ml

<Resin composition> Film-forming property (Example 1)
The copolymer 1 obtained in Synthesis Example 1 was dissolved in 4 g of toluene in 6 g to form a resin solution, the polymer was completely dissolved, a film was formed on a silicon wafer using a spin coater, and the mixture was dried at 120 ° C. for 5 minutes. This was performed to obtain a 20 μm resin film.
The obtained resin film was heated at 150 ° C. for 1 hour in a nitrogen atmosphere and returned to room temperature. When the resin film was immersed in hexane, the residual film ratio calculated by the following formula was 58%.
Further, the dried 20 μm resin film was heated at 180 ° C. for 30 minutes in a nitrogen atmosphere and returned to room temperature. When the resin film was immersed in hexane, the residual film ratio calculated by the following formula was 84%.
(formula)
Remaining film ratio (%) = {(Thickness of resin film immersed in hexane after heating (μm)) / (Film thickness of resin film after drying: 20 μm)} × 100

(Example 2)
The copolymer 2 obtained in Synthesis Example 2 is dissolved in 4 g of toluene in 6 g to form a resin solution, the polymer is completely dissolved, a film is formed on a silicon wafer using a spin coater, and the mixture is dried at 120 ° C. for 5 minutes. This was performed to obtain a 20 μm resin film.
The obtained resin film was heated at 150 ° C. for 1 hour in a nitrogen atmosphere and returned to room temperature. When the resin film was immersed in hexane, the residual film ratio calculated by the above formula was 63%.
Further, the dried 20 μm resin film was heated at 180 ° C. for 30 minutes in a nitrogen atmosphere and returned to room temperature. When the resin film was immersed in hexane, the residual film ratio calculated by the above formula was 94%.

(Comparative Example 1)
The homopolymer 1 obtained in Synthetic Comparative Example 1 was dissolved in 2 g of toluene in 8 g to form a resin solution, the polymer was completely dissolved, a film was formed on a silicon wafer using a spin coater, and the mixture was dried at 120 ° C. for 5 minutes. This was performed to obtain a 20 μm resin film.
The obtained resin film was heated at 150 ° C. for 1 hour in a nitrogen atmosphere and returned to room temperature. When the resin film was immersed in hexane, the residual film ratio calculated by the above formula was 0%.

(Comparative Example 2)
The homopolymer 2 obtained in Synthetic Comparative Example 2 was dissolved in 4 g of toluene in 6 g to form a resin solution, the polymer was completely dissolved, a film was formed on a silicon wafer using a spin coater, and the mixture was dried at 120 ° C. for 5 minutes. A 10 μm resin film was obtained, but cracks were formed and it was difficult to form the film.

<Measurement of 1MHz permittivity>
The polymer was formed into a 4-inch silicon wafer with a spin coater, dried at 120 ° C. for 10 minutes, and heated at 180 ° C. for 30 minutes under vacuum to obtain a film formation of 2.0 μm.
Table 1 below shows the results of calculating the relative permittivity and the dielectric loss tangent by measuring the parallel capacitance Cp and conductance G at a measurement frequency of 1 MHz using an HP-4284A manufactured by Agilent Technologies.

<Transparency evaluation>
The polymer was formed on a pet film, vacuum dried at 100 ° C. for 60 minutes, peeled off from the pet film, and further heated under a vacuum at 180 ° C. for 30 minutes to obtain a 50 μm film. The total ray measurement rate of the film obtained based on JIS-K-7361 was measured.

The curable resin composition for a low dielectric constant material of the present invention containing a polymer containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) is shown in the table. As described in No. 1, it was clarified that a transparent cured product having excellent low dielectric constant can be obtained. Further, the curable resin composition for a low dielectric constant material of the present invention has excellent film forming properties and has a B-stage state and a C-stage state. Therefore, an interlayer insulating film and a circuit constituting a multilayer wiring structure of a semiconductor element. It has been clarified that the build-up layer or the core layer constituting the substrate has excellent manufacturing stability and is suitably used for the semiconductor application.

Claims (11)

Curing for low dielectric constant materials containing a polymer containing at least one structural unit a represented by the following general formula (1) and at least one structural unit b represented by the following general formula (2). Sex resin composition.

(In the general formula (1), m is 0, 1 or 2.
In the general formula (2), X represents a linear or branched alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group. n is 0, 1 or 2. ) The curable resin composition for a low dielectric constant material according to claim 1, wherein the polymer further contains at least one structural unit c represented by the following general formula (3).

(In the general formula (3), R independently represent an alkoxy group having 1 to 3 carbon atoms or an alkyl group having 1 to 3 carbon atoms, and at least two Rs are alkoxy groups having 1 to 3 carbon atoms. .L is 0, 1 or 2. p is an integer from 0 to 3.) The curable resin composition for a low dielectric constant material according to claim 1 or 2, wherein the polymer does not contain a polar functional group. The curable resin composition for a low dielectric constant material according to any one of claims 1 to 3, wherein the polymer does not contain a structural unit derived from maleic acid or maleimide. The curable resin composition for a low dielectric constant material according to any one of claims 1 to 4, further comprising a curing catalyst. The curable resin composition for a low dielectric constant material according to claim 5, wherein the curing catalyst is a photoacid generator or a photoradical generator. The 20 μm resin film A obtained by applying the curable resin composition for a low dielectric constant material and drying at 120 ° C. for 5 minutes was applied.
The residual film ratio calculated by the following formula from the film thickness of the resin film B after heating at 150 ° C. for 1 hour and then immersing in hexane for 2 minutes is 50% or more.
The residual film ratio calculated by the following formula from the film thickness of the resin film B'after heating at 180 ° C. for 30 minutes and then immersing in hexane for 2 minutes is 70% or more.
The curable resin composition for a low dielectric constant material according to any one of claims 1 to 6.
(formula)
Remaining film ratio (%) = {(Film thickness (μm) of resin film B (or B') immersed in hexane after heating) / (Film thickness of resin film A after drying: 20 μm)} × 100 A cured product obtained by curing the curable resin composition for a low dielectric constant material according to any one of claims 1 to 7. The cured product according to claim 8, wherein the relative permittivity at a frequency of 1 MHz is 2.6 or less, and the dielectric loss tangent (tan δ) is 0.005 or less. A resin film comprising the cured product according to claim 8 or 9, having a film thickness of 10 μm or more. A low dielectric constant material comprising the cured product according to claim 8 or 9.