JP7809968B2 - Thermosetting resin, resin varnish, and curable resin composition - Google Patents

Description

The present invention relates to a thermosetting resin, a resin varnish, a curable resin composition, and a method for producing the resin.

Norbornene-based resins have traditionally been characterized by their excellent electrical and optical properties, low moisture absorption, and other characteristics, and have been used in a variety of molded products.

Patent Document 1 discloses a resin composition containing a cyclic olefin homopolymer with a glass transition temperature of 101 to 160°C, a fibrous conductive filler, and another elastomer. It states that molding materials obtained from this resin composition have excellent mechanical strength, heat resistance, and conductivity.

Patent Document 2 discloses a method for producing a polycyclic olefin polymer by polymerizing a polycyclic olefin monomer in the presence of a palladium catalyst complex and a chain transfer/activation agent.

JP 2013-231171 A Special Publication No. 2010-523766

However, the polymers described in Patent Documents 1 and 2 are not thermosetting, have low solubility in organic solvents, and there is room for improvement in the low dielectric properties of the resulting cured products.

The present inventors have discovered that a resin comprising structural units derived from a specific norbornene-based monomer is thermosetting, has excellent solubility in organic solvents, and also has excellent dielectric properties, and have thereby completed the present invention.
That is, the present invention can be shown as follows.

According to the present invention,
A structural unit a represented by the following general formula (1),
A structural unit b represented by the following general formula (2),
and a thermosetting resin having a weight average molecular weight of 500 or more and 10,000 or less.
(In general formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and n is 0, 1 or 2.)
(In general formula (2), Q represents a group containing a group having a terminal double bond, and m is 0, 1, or 2.)

According to the present invention,
The thermosetting resin;
and an organic solvent.

According to the present invention,
a thermosetting resin;
a radical polymerization initiator;
It is possible to provide a curable resin composition comprising:

According to the present invention,
The method includes a step of reacting a compound a1 represented by the following general formula (1a) with a compound b1 represented by the following general formula (2a) in an organic solvent in the presence of a polymerization catalyst and a chain transfer agent:
the organic solvent includes at least one selected from a ketone-based solvent, an ether-based solvent, an ester-based solvent, an aliphatic alcohol-based solvent, and an aromatic solvent;
The method for producing the thermosetting resin can be provided, wherein the chain transfer agent contains at least one selected from a trialkylsilane compound and a cyclobutene compound.
(In general formula (1a), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms; and n is 0, 1 or 2.)
(In general formula (2a), Q represents a group containing a group having a terminal double bond, and m is 0, 1, or 2.)

The cyclic olefin resin of the present invention is thermosetting, has excellent solubility in organic solvents, and also has low dielectric properties.

1 is a graph showing the dielectric loss tangent of the film obtained in Example 2 measured at 10 GHz.

The present invention will be described below based on the embodiments. Unless otherwise specified, "~" indicates "above" to "below."

[Thermosetting resin]
The thermosetting resin of the present embodiment contains a structural unit a represented by the following general formula (1) and a structural unit b represented by the following general formula (2), and has a weight average molecular weight of 500 or more and 10,000 or less.

In the general formula (1), n is 0, 1 or 2, preferably 0 or 1.
R ¹ , R ² , R ³ and R ⁴ each independently represent hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms. Multiple R ¹ s, R ² s, R ³ s and R ⁴ s present in the thermosetting resin may be the same or different.

Examples of hydrocarbon groups having 1 to 30 carbon atoms include alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups.

Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, and decyl groups.
Alkenyl groups include, for example, allyl, pentenyl, and vinyl groups, and alkynyl groups include ethynyl groups.
Alkylidene groups include, for example, methylidene and ethylidene groups.

Examples of aryl groups include phenyl, naphthyl, and anthracenyl groups. Examples of aralkyl groups include benzyl and phenethyl groups.

Examples of the alkaryl group include tolyl and xylyl groups, and examples of the cycloalkyl group include adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl groups.
The hydrocarbon group having 1 to 30 carbon atoms may contain at least one atom selected from O, N, S, P and Si in its structure.

In this embodiment, the hydrocarbon group having 1 to 30 carbon atoms is preferably a hydrocarbon group having 1 to 15 carbon atoms, and more preferably a hydrocarbon group having 1 to 10 carbon atoms. Furthermore, the hydrocarbon group having 1 to 30 carbon atoms is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms.

Substituents on the substituted hydrocarbon group having 1 to 30 carbon atoms include hydroxyl groups, amino groups, cyano groups, ester groups, ether groups, amide groups, and sulfonamide groups, and the group may be substituted with at least one type of group.

In this embodiment, it is preferred that one of R ¹ , R ² , R ³ and R ⁴ is a substituted or unsubstituted hydrocarbon group having 1 to 30 carbon atoms, and the rest are hydrogen atoms, and it is more preferred that all are hydrogen atoms.

In the general formula (2), m is 0, 1 or 2, preferably 0 or 1.
Q represents a group having a terminal double bond.
Groups having a terminal double bond include vinyl groups, (meth)acryloyl groups, or vinylphenyl groups.

Examples of groups having a terminal double bond include vinyl groups, (meth)acryloyl groups, vinylphenyl groups, (meth)acryloylalkyl groups, (meth)acryloyloxyalkyl groups, vinylphenylalkyl groups, and vinylphenyloxyalkyl groups, and these groups may contain ether bonds or thioether bonds in the alkylene chain.

Specific examples of the structural unit b represented by general formula (2) include structural units derived from vinylnorbornene, structural units derived from butenylnorbornene, structural units derived from hexenylnorbornene, and structural units represented by the following formulas, and one or more selected from these can be used.

From the viewpoint of thermosetting property and solvent solubility, the thermosetting resin of this embodiment can have a molar ratio of structural unit b to structural unit a (b/a) of 0.1 or more and 4 or less, preferably 0.1 or more and 3.5 or less, and more preferably 0.15 or more and 3 or less.

The thermosetting resin of this embodiment contains structural units a and b, and may contain structural units derived from other monomers in addition to these structural units.

Other monomers include indene, styrene, acenaphthylene, norbornadiene, terpene compounds (e.g., pinene, limonene, etc.), linear alkenes (e.g., pentene, etc.), and cyclic alkenes (cyclohexene, etc.).

The thermosetting resin of this embodiment does not contain structural units derived from ethylene or α-olefins, nor does it contain structural units derived from maleic acid, maleimide, maleic anhydride, etc., which affect the dielectric constant.

From the viewpoint of low dielectric constant, the thermosetting resin has a total amount of structural units a and b of 80 mol % or more, preferably 90 mol %, and more preferably 95 mol % or more, based on 100 mol % of all structural units. The upper limit is not particularly limited, but is preferably 100 mol % or less.

From the viewpoint of the effects of the present invention, the weight average molecular weight (Mw) of the thermosetting resin is 500 or more and 10,000 or less, preferably 600 or more and 8,000 or less, and more preferably 700 or more and 7,000 or less.

If the weight-average molecular weight is below the lower limit, it may affect thermosetting properties, while if it exceeds the upper limit, it may decrease solubility in solvents, reducing handleability and affecting the preparation of prepregs, etc. In other words, when the weight-average molecular weight of a thermosetting resin is within the above range, it will have excellent thermosetting properties, high solubility in organic solvents, and excellent handleability, making it suitable for use in prepregs, etc.

The thermosetting resin of this embodiment may have a weight-average molecular weight (Mw)/number-average molecular weight (Mn) ratio of, for example, 1.0 to 6.0, preferably 1.2 to 5.0, and more preferably 1.5 to 4.0. Note that Mw/Mn is the dispersity, which indicates the width of the molecular weight distribution.

The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) are polystyrene-equivalent values obtained from a calibration curve of standard polystyrene (PS) obtained by, for example, GPC (Gel Permeation Chromatography) measurement. The measurement conditions are, for example, as follows:
Tosoh gel permeation chromatography device HLC-8320GPC
Column: TSK-GEL Supermultipore HZ-M manufactured by Tosoh Corporation
Detector: RI detector for liquid chromatography Measurement temperature: 40°C
Solvent: THF
Sample concentration: 2.0 mg/milliliter

The thermosetting resin of this embodiment has a solubility in toluene at 25° C. of 30 wt % or more, preferably 50 wt % or more, and more preferably 60 wt % or more. The solubility is calculated by the following formula.
Formula: [Weight of thermosetting resin/(Weight of thermosetting resin+Weight of toluene)]×100
Because of its high solubility in organic solvents, it has excellent film-forming properties and compatibility with other resins.

A film containing the thermosetting resin of this embodiment produced under the following test conditions has a dielectric loss tangent (tan δ) of 0.006 or less, preferably 0.004 or less, and more preferably 0.003 or less, when measured at a frequency of 10 GHz. By including the thermosetting resin of this embodiment, the dielectric properties of the film or the like can be further improved.
(Test conditions)
A toluene solution (resin concentration 30 wt%) containing polyhexylnorbornene (a) (pHexNB, Mw: 100,000) and the thermosetting resin (b) of this embodiment mixed in a blending ratio ((a):(b)) of 70 parts by mass:30 parts by mass is applied to a substrate, and the coating is dried at 60°C for 15 to 30 minutes and then at 90°C for 15 to 30 minutes to obtain a film with a thickness of 100 μm. The dielectric loss tangent at 10 GHz of the obtained film is measured using a cavity resonator method.

The thermosetting resin of this embodiment has excellent melting properties (or excellent embeddability during substrate fabrication), and its melting temperature is, for example, 250°C or lower, preferably 230°C or lower, and more preferably 200°C or lower. The lower limit of the melting temperature is 50°C or higher, preferably 60°C or higher, and more preferably 70°C or higher. Because the thermosetting resin of this embodiment is thermosetting and has the above melting temperature, it has excellent manufacturing stability for interlayer insulating films that constitute the multilayer wiring structure of semiconductor elements, build-up layers or core layers that constitute circuit boards, and the like, and can be suitably used for these semiconductor applications.

[Method for synthesizing thermosetting resin]
The method for synthesizing the thermosetting resin of this embodiment includes, for example,
The method includes a step of reacting a compound a1 represented by the following general formula (1a) with a compound b1 represented by the following general formula (2a) in an organic solvent in the presence of a polymerization catalyst and a chain transfer agent.

In formula (1a), R ¹ , R ² , R ³ , R ⁴ and n have the same meanings as in formula (1).

In formula (2a), Q and m have the same meanings as in formula (1).
Specific examples of the compound b1 represented by general formula (2a) include vinyl norbornene, butenyl norbornene, hexenyl norbornene, and compounds represented by the following formulae (from the left, bicyclo[2.2.1]hept-5-en-2-yl methacrylate, 2-propenoic acid 2-methyl-bicyclo[2.2.1]hept-5-en-2-ylmethyl ester, 2-propenoic acid bicyclo[2.2.1]hept-5-en-2-ylmethyl ester, and 5-[[(4-ethenylphenyl)methoxy]methyl]bicyclo[2.2.1]hept-2-ene), and one or more selected from these can be used.

In this embodiment, first, the compound a1, the compound b1, and a chain transfer agent are dissolved in an organic solvent, and then the solution is preheated to about 40° C. to 85° C. The compound a1 can be added in multiple batches by adjusting the amount added, or the compound a1 can be dissolved in the organic solvent or the chain transfer agent and added in multiple batches.
The molar ratio (b1/a1) of the compound b1 represented by the following general formula (2a) to the compound a1 represented by the general formula (1a) can be set to 0.1 or more and 4 or less, preferably 0.1 or more and 3.5 or less, and more preferably 0.15 or more and 3 or less, from the viewpoint of thermosetting properties.

A catalyst dilution solution is prepared by diluting the polymerization catalyst and, if necessary, a cocatalyst in an organic solvent, and added to the heated mixed solution. The catalyst dilution solution may be added all at once or dropwise. Examples of dilution solvents include toluene, ethyl acetate, and tetrahydrofuran, and one or more of these can be used in combination.

The diluted catalyst solution is added to the mixed solution, and then heated for a predetermined period of time to carry out solution polymerization.
In this case, the heating temperature may be, for example, about 30° C. to 200° C., and the heating time may be, for example, 0.5 to 72 hours. It is more preferable to carry out the solution polymerization after removing dissolved oxygen in the solvent by nitrogen bubbling.
If necessary, a molecular weight modifier can be used.

Examples of the organic solvent include ketone solvents, ether solvents, ester solvents, acyclic aliphatic alcohol solvents, and aromatic solvents, and one or more selected from these can be used. Specific examples of these organic solvents include cyclopentanone, heptanone, anisole, butanol, and toluene, and one or more selected from these can be used.

By using these organic solvents, it is possible to obtain cyclic olefin resins that are thermosetting, have excellent solubility in organic solvents, and also have low dielectric properties.

Examples of chain transfer agents include trialkylsilane compounds such as trimethylsilane, triethylsilane, and tributylsilane, and cyclobutene compounds such as bicyclo[4.2.0]oct-7-ene. These chain transfer agents may be used alone or in combination of two or more.

By using these chain transfer agents, it is possible to obtain a cyclic olefin resin that is thermosetting, has excellent solubility in organic solvents, and also has excellent low dielectric properties.
In this embodiment, from the viewpoint of obtaining a desired cyclic olefin resin, it is more preferable to use the organic solvent and the chain transfer agent in combination.

There is no particular restriction on the polymerization catalyst as long as it allows addition polymerization to proceed. For example, palladium complexes and nickel complexes may be coordinated with phosphine, diimine, or nitrile ligands, and counter anions may be used. One or more of these may be used.

Examples of the palladium complex include palladium(II)(acetonitrile)bis(triisopropylphosphine)acetatetetrakis(2,3,4,5,6-pentafluorophenyl)borate,
allylpalladium complexes such as π-allylpalladium chloride dimer;
Palladium organic carboxylates such as palladium acetate, propionate, maleate, and naphthoate;
complexes of palladium with organic carboxylic acids such as a triphenylphosphine complex of palladium acetate, a tri(m-tolyl)phosphine complex of palladium acetate, a tricyclohexylphosphine complex of palladium acetate, and a triisopropylphosphine complex of palladium acetate;
palladium dibutyl phosphite, palladium p-toluenesulfonate and other organic sulfonates of palladium;
β-diketone compounds of palladium such as bis(acetylacetonato)palladium, bis(hexafluoroacetylacetonato)palladium, bis(ethylacetoacetate)palladium, and bis(phenylacetoacetate)palladium;

Examples include palladium halide complexes such as dichlorobis(triphenylphosphine)palladium, bis[tri(m-tolylphosphine)]palladium, dibromobis[tri(m-tolylphosphine)]palladium, and acetonyltriphenylphosphonium complexes.

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

Examples of the counter anion include tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbenium tetrakis(2,4,6-trifluorophenyl)borate, triphenylcarbenium tetraphenylborate, and tributylammonium tetrakis(pentafluorophenyl)borate.
The polymerization catalyst can be used in an amount of 1 ppmmol to 1000 ppmmol based on the norbornene-based monomers (compound a1 and compound b1).

The pre-cocatalyst preferably contains an ionic complex containing a weakly coordinating anion salt. In other words, when synthesizing the addition-type norbornene-based resin, it is preferable to add a co-catalyst in addition to the catalyst. This can further increase the polymerization rate of the addition-type norbornene-based monomer.

The co-catalyst is not particularly limited, but examples include alkylaluminum, Lewis acids, and ionic complexes containing weakly coordinating anion (WCA) salts, and among these, ionic complexes containing weakly coordinating anion (WCA) salts are preferred.

Furthermore, the promoter is more preferably one represented by the following formula (i):
[C] _e [WCA] _d formula (i)
(In the above formula, C represents a proton (H ⁺ ), an organic radical-containing cation, or an alkali metal, alkaline earth metal, or transition metal cation; WCA is as defined above; and e and d are numbers determined to balance the electronic charge on the overall salt complex of the cation complex (C) and the weakly coordinating anion salt (WCA), respectively.)

Examples of ionic complexes containing the weakly coordinating anion (WCA) salt include, but are not limited to, lithium(diethyl ether) _2.5 tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, H( _OEt2 ) _x tetrakis(pentafluorophenyl)borate, tetrakis[(4-methyl)-α,α-bis(trifluoromethyl)benzenemethanolato-κO]aluminate, sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, trialkyl and triarylphosphonium tetrakis(pentafluorophenyl)borate, and trityl tetrakis(pentafluorophenyl)borate.
The co-catalyst can be used in an amount of 1 ppmmol to 1000 ppmmol relative to the norbornene-based monomers (compound a1 and compound b1).

The resulting reaction solution containing the thermosetting resin is added to an alcohol such as hexane or methanol to precipitate the thermosetting resin, which is then filtered, washed with an alcohol such as hexane or methanol, and dried.
In this embodiment, for example, a thermosetting resin can be synthesized in this manner.

[Resin varnish]
In this embodiment, a polymer solution (resin varnish) in which a thermosetting resin is dissolved in an organic solvent can be prepared. In this polymer solution (resin varnish), at a liquid temperature of 25° C., it is sufficient that at least a portion of the polymer is dissolved, but it is preferable that all of the polymer is dissolved.

Organic solvents used in resin varnishes include acetone, ethyl acetate, cyclohexane, heptane, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, N-methylpyrrolidone, propylene glycol monomethyl ether, methyl ether acetate, toluene, cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone. Organic solvents selected from these can be used alone or in combination of two or more.

The lower limit of the thermosetting resin 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, and even more preferably 15% by mass or more, relative to 100% by mass of the resin varnish. On the other hand, the upper limit of the thermosetting resin 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, and even more preferably 35% by mass or less, relative to 100% by mass of the resin varnish. By keeping the content within this numerical range, the handleability of the resin varnish can be improved, and a resin material with excellent heat resistance can be achieved.

[Curable resin composition]
The curable resin composition of the present embodiment can be prepared using a resin varnish by mixing a thermosetting resin, a curing catalyst, and, if necessary, other components described below. The curable resin composition of the present embodiment can provide a low dielectric constant material.

As long as the effects of the present invention can be achieved, known curing catalysts that accelerate curing by heat or light can be used. Examples of curing catalysts include thermal acid generators, photoacid generators, and photoradical generators.

Examples of thermal acid generators include aromatic sulfonium salts, aromatic iodonium salts, ammonium salts, aluminum chelates, and boron trifluoride amine complexes. One or more of these may be included as the thermal acid generator.

Examples of photoacid generators include onium salt compounds, specifically cationic photopolymerization initiators such as diazonium salts, iodonium salts such as diaryliodonium salts, sulfonium salts such as triarylsulfonium salts, triarylpyrilium salts, benzylpyridinium thiocyanate, dialkylphenacylsulfonium salts, and dialkylhydroxyphenylphosphonium salts.
The photoacid generator and the thermal acid generator may be used in combination.

Specific examples of the photoradical generator include alkylphenone compounds such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone;
Benzophenone-based compounds such as benzophenone, 4,4'-bis(dimethylamino)benzophenone, and 2-carboxybenzophenone; benzoin-based compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;
Thioxanthone compounds such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, and 2,4-diethylthioxanthone;
halomethylated triazine compounds such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-ethoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(4-ethoxycarboxynylnaphthyl)-4,6-bis(trichloromethyl)-s-triazine;
halomethylated oxadiazole compounds such as 2-trichloromethyl-5-(2'-benzofuryl)-1,3,4-oxadiazole, 2-trichloromethyl-5-[β-(2'-benzofuryl)vinyl]-1,3,4-oxadiazole, 4-oxadiazole, and 2-trichloromethyl-5-furyl-1,3,4-oxadiazole;
Biimidazole compounds such as 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, and 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole;
Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime);
Titanocene compounds such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-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.

In addition, sensitivity and the degree of crosslinking can be further improved by using a photosensitizer or photoradical polymerization accelerator in addition to the above-mentioned photoradical generator. Examples include dye-based compounds such as xanthene dyes and coumarin dyes, dialkylaminobenzene-based compounds such as ethyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-dimethylaminobenzoate, and mercapto-based hydrogen donors such as 2-mercaptobenzothiazole and 2-mercaptobenzimidazole.

(Other ingredients)
The curable resin composition of the present embodiment may contain other components such as fillers, resins other than thermosetting resins, crosslinking agents, acid generators, heat resistance improvers, developing aids, plasticizers, polymerization inhibitors, ultraviolet absorbers, antioxidants, matting agents, antifoaming agents, leveling agents, antistatic agents, dispersants, slip agents, surface modifiers, thixotropic agents, thixotropic aids, surfactants, silane-based, aluminum-based, titanium-based or other coupling agents, polyhydric phenol compounds, and organic solvents, depending on the purpose and required properties of each application.

The curable resin composition for low dielectric constant materials of this embodiment contains a polymer obtained by polymerizing a specified norbornene-based monomer. It is thermosetting, has excellent handleability, and can provide a low dielectric constant material. As a result, it has excellent manufacturing stability for interlayer insulating films that make up the multilayer wiring structure of semiconductor elements, build-up layers or core layers that make up circuit boards, and the like, and is suitable for use in these semiconductor applications.

[Application]
The curable resin composition of the present embodiment can be cured by removing the organic solvent by drying or the like as needed, and curing the composition by light or heat, or a combination of light and heat, to obtain a cured product.

Thermal curing can be carried out in air, a nitrogen atmosphere, or a vacuum. If transparency is required for the resulting cured product, it is preferable to carry out the curing in a nitrogen atmosphere or a vacuum, or to use an antioxidant in combination.

The relative dielectric constant of the cured product at a frequency of 10 GHz can be preferably 2.6 or less, more preferably 2.4 or less, which allows the cured product to be used as a low dielectric constant material.
Furthermore, the dielectric loss tangent (tan δ) of the cured product at a frequency of 10 GHz is preferably 0.004 or less, and more preferably 0.003 or less, thereby further improving the dielectric properties of the cured product.

This low-dielectric-constant material can be used in a variety of applications, including those requiring heat resistance and film-like use. Furthermore, the low-dielectric-constant material can provide a resin film (low-dielectric-constant film) with excellent transparency.
Specific applications include printed circuit boards and resin film formation such as permanent films.
The printed circuit board can be obtained by impregnating a low dielectric cloth such as a glass cloth with a curable resin composition and curing the composition.

On the other hand, resin films are known to be used in, but are not limited to, interlayer films, surface protection films, and dam materials. As described below, resin films are used in electronic components and devices such as semiconductor elements and in their manufacturing processes.

Interlayer films refer to insulating films formed within a multilayer structure, and there are no particular limitations on the type. Examples of interlayer films include those used in semiconductor applications, such as interlayer insulating films that form the multilayer wiring structure of semiconductor elements, and build-up or core layers that form circuit boards. Other examples of interlayer films include those used in display element applications, such as planarizing films that cover thin-film transistors in display devices, liquid crystal alignment films, protrusions formed on color filter substrates in MVA-type liquid crystal display devices, and partition walls for forming the cathodes of organic EL elements.

A surface protection film is a film formed on the surface of an electronic component or device, or on the surface of a substrate on which these components or devices are formed, to protect the surface. Examples of such a surface protection film include a passivation film, a bump protection film, or a buffer coat layer formed on a semiconductor element, or a cover coat formed on a flexible substrate, and these films have excellent adhesion to an underlying layer made of an organic or inorganic material.
The dam material is a spacer used to form a hollow portion on the substrate for arranging an optical element or the like.

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

In this embodiment, the thickness of the resin film can be appropriately adjusted depending on the application. 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, or 30 μm or less.
By using the curable resin composition of this embodiment, cracks do not occur even in a resin film having a thickness within the above range.

The above describes embodiments of the present invention, but these are merely examples of the present invention, and various other configurations can be adopted as long as they do not impair the effects of the present invention.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

[Example 1]
A reaction solution was obtained by adding norbornene (NB) (75% concentration toluene solution), 5-vinyl-2-norbornene (VNB), triethylsilane, 1-butanol, and cyclopentanone to a three-neck flask in the weight ratios shown in Table 1 below. After bubbling nitrogen through the reaction solution, it was heated to 75°C.
A catalyst (palladium (II) (acetonitrile) bis(triisopropylphosphine) acetate tetrakis(2,3,4,5,6-pentafluorophenyl)borate, Pd-1206) and a co-catalyst (N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, DANFABA) were dissolved in a toluene:ethyl acetate = 6:4 solution to prepare a solution, and added to the reaction solution so that the total amount of norbornene monomer:catalyst:co-catalyst = 20,000:1:1 (molar ratio). Polymerization was then carried out by heating at the temperature and for the time shown in Table 1 below. After completion of polymerization, the reaction was stopped by allowing to cool.
After the reaction was completed, 115 g of the reaction solution was dropped into a mixed solution of 500 g of methanol and 100 g of THF to cause reprecipitation. The precipitated polymer was filtered off, air-dried, and then dissolved in 60 g of toluene and 30 g of THF. The dissolved liquid was dropped into a mixed solution of 500 g of methanol and 100 g of THF to cause reprecipitation again. The polymer was recovered by filtration, and then washed with a mixed solution of 100 g of methanol and 20 g of THF and filtered off. Finally, the polymer was dried in a vacuum at 80°C to obtain a purified polymer.
The composition ratio of norbornene and 5-vinyl-2-norbornene in the obtained polymer was calculated by ¹ H-NMR measurement.

[Example 2]
Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 1, except that cyclopentanone was replaced with anisole. After completion of the reaction, 110 g of the reaction solution was dropped into a mixture of 500 g of methanol and 150 g of THF to cause reprecipitation. The polymer was recovered by filtration, and then washed with a mixture of 100 g of methanol and 100 g of THF and separated by filtration. Finally, the polymer was vacuum dried at 80°C to obtain a purified polymer.

[Example 3]
Polymerization was carried out in the same manner as in Example 1, except that cyclopentanone was replaced with 2-heptanone (MAK) under the conditions shown in Table 1 below. After completion of the reaction, 120 g of the reaction solution was added dropwise to 500 g of methanol to cause reprecipitation. The polymer was recovered by filtration, and then the residue was washed with a mixture of 150 g of methanol and 50 g of THF and separated by filtration. Finally, the polymer was vacuum dried at 80°C to obtain a purified polymer.

[Example 4]
Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 1 below, except that 5-vinyl-2-norbornene was replaced with 5-(5-hexen-1-yl)bicyclo[2.2.1]hept-2-ene (HNB). After completion of the reaction, 113 g of the reaction solution was added dropwise to 850 g of methanol to cause reprecipitation. The precipitated polymer was separated by filtration, air-dried, and then dissolved in 90 g of toluene and 180 g of THF. The dissolved liquid was added dropwise to 2,450 g of methanol to cause reprecipitation again, and the polymer was separated by filtration. Finally, the polymer was vacuum-dried at room temperature to obtain a purified polymer.

[Example 5]
Polymerization was carried out in the same manner as in Example 1, except that 5-vinyl-2-norbornene was replaced with 5-(3-buten-1-yl)bicyclo[2.2.1]hept-2-ene (BNB) under the conditions shown in Table 1 below. After completion of the reaction, 68 g of the reaction solution was added dropwise to 510 g of methanol to cause reprecipitation. The precipitated polymer was separated by filtration, air-dried, and then dissolved in 40 g of THF. The dissolved liquid was added dropwise to 430 g of methanol to cause reprecipitation again, and the polymer was separated by filtration. Finally, the polymer was vacuum-dried at room temperature to obtain a purified polymer.

[Comparative Example 1]
Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 1 below, except that the mixed solvent of cyclopentanone and 1-butanol was changed to cyclopentanol.

[Comparative Example 2]
Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 1 below, except that the chain transfer agent was changed from triethylsilane to 1-hexene.

[Comparative Example 3]
Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Table 1 below. After the reaction was completed, 47.5 g of THF was added to 56 g of the reaction solution to disperse the precipitate, which was then added dropwise to a mixed solution of 760 g of methanol and 152 g of THF to cause reprecipitation. The polymer was recovered by filtration, and the residue was washed with a mixed solution of 380 g of methanol and 76 g of THF and then filtered off. Finally, the polymer was vacuum dried at room temperature to obtain a purified polymer.

[Example 6]
In addition to triethylsilane, bicyclo[4.2.0]oct-7-ene (BCO) was added as a chain transfer agent, and the solvent was changed from a mixed solvent of cyclopentanone and 1-butanol to toluene, and polymerization was carried out in the same manner as in Example 1 under the conditions in Table 1 below. After completion of the reaction, 87 g of the reaction solution was added dropwise to 350 g of isopropanol to cause reprecipitation, which was then filtered off. Finally, the remaining solvent was removed by vacuum drying at 80°C, and a purified polymer was obtained.

[Example 7]
In addition to triethylsilane as a chain transfer agent, BCO was added, and the solvent was changed from a mixed solvent of cyclopentanone and 1-butanol to a solvent of cyclopentanone only, and polymerization was carried out in the same manner as in Example 1 under the conditions in Table 1 below. After completion of the reaction, 18 g of the reaction solution was added dropwise to 80 g of methanol to cause reprecipitation. The polymer was recovered by filtration, and then the residue was washed with a mixed liquid of 40 g of methanol and separated by filtration. Finally, the remaining solvent was removed by vacuum drying at 80°C, and a purified polymer was obtained.

[Example 8]
The co-catalyst was changed to lithium tetrakis(pentafluorophenyl)borate-ethyl ether complex, and further 5-vinyl-2-norbornene was changed to 5-(5-hexen-1-yl)bicyclo[2.2.1]hept-2-ene (HNB), and polymerization was carried out with additional addition under the conditions shown in Table 2 below in the same manner as in Example 1. The additional addition was carried out in three divided additions over 40 minutes, 70 minutes, and 95 minutes in the amount shown in Table 2 below.
After the reaction was completed, 88 g of the reaction solution was added dropwise to 620 g of methanol to cause reprecipitation. The precipitated polymer was filtered off, air-dried, and then dissolved in a mixed solution of 18 g of THF and 37 g of toluene. The dissolved liquid was added dropwise to 370 g of methanol to cause reprecipitation again, and then filtered. The residue was washed with 50 g of methanol and filtered. Finally, the polymer was vacuum-dried at room temperature to obtain a purified polymer.

[Example 9]
The co-catalyst was changed to lithium tetrakis(pentafluorophenyl)borate-ethyl ether complex, and further 5-vinyl-2-norbornene was changed to 5-(5-hexen-1-yl)bicyclo[2.2.1]hept-2-ene (HNB), and polymerization was carried out under the conditions shown in Table 2 below in the same manner as in Example 1. The additional addition was carried out in four divided additions over 23 minutes, 55 minutes, 95 minutes, and 135 minutes in the amount shown in Table 2 below.
After the reaction was completed, 76 g of the reaction solution was added dropwise to 570 g of methanol to cause reprecipitation. The precipitated polymer was filtered off, air-dried, and then dissolved in a mixed solution of 30 g of THF and 65 g of toluene. The dissolved liquid was added dropwise to 680 g of methanol to cause reprecipitation again, and then filtered. The residue was washed with 110 g of methanol and filtered. Finally, the polymer was vacuum-dried at room temperature to obtain a purified polymer.

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

As shown in Tables 1 and 2, oligomers with molecular weights of approximately Mw 800 to 5000 were obtained in the examples. Comparative Example 1, which used cyclopentanol as the organic solvent, had a low molecular weight and was prone to evaporation, posing a problem in terms of the generation of voids during reflow. Comparative Example 2, which used 1-hexene as the chain transfer agent, had a high molecular weight, which reduced solubility in solvents and made it easier to handle, which is expected to affect the preparation of prepregs, etc.

<Melting temperature>
Using a TGDTA measuring device (STA7200RV manufactured by Hitachi), the temperature was raised from 30°C at a rate of 5°C/min under nitrogen conditions, and the change in appearance was obtained as image data. The temperature range from the temperature at which dissolution began to the temperature at which the entire solution was confirmed based on the image data was taken as the dissolution temperature.

<Toluene solubility>
0.3 g of the obtained polymer was added to 0.2 g of toluene, and it was confirmed by visual inspection (under normal lighting) that the polymer was transparent and had no insoluble residues, and the result was evaluated according to the following criteria.
(standard)
〇: Dissolved △: Some remains undissolved ×: Insoluble

<Toluene/methyl ethyl ketone (MEK) solubility>
0.3 g of the obtained polymer was added to 0.2 g of a mixed solvent of toluene/methyl ethyl ketone (mixing ratio: 1/1), and the polymer was visually confirmed (under normal lighting) to be transparent and free of undissolved residues, and evaluated according to the above criteria.

<Methyl isobutyl ketone (MIBK)/cyclohexanone solubility>
0.3 g of the obtained polymer was added to 0.3 g of a mixed solvent of methyl isobutyl ketone (MIBK)/cyclohexanone (mixing ratio: 1/1), and the resultant solution was visually confirmed (under normal lighting) to be transparent and free of undissolved residues, and evaluated according to the above criteria.

<Thermosetting test>
0.5 g of the obtained polymer was dissolved in 0.5 g of a mixed solvent of methyl-n-amyl ketone (MAK)/decane (mixing ratio: 1/1), and 0.01 g of Perbutyl P, a radical polymerization initiator, was added. The resulting mixture was heated and maintained at 130°C for 1 hour. The change in weight average molecular weight (Mw) was confirmed by the above GPC measurement using the following formula:
Equation: Weight average molecular weight (Mw) of polymer after heating at 130°C for 1 hour/Weight average molecular weight (Mw) of polymer before heating

As shown in Table 3, the resins of the examples have excellent solubility in organic solvents, making them easy to handle. Furthermore, because they are thermosetting and have the dissolution temperatures described above, they are expected to have excellent manufacturing stability for interlayer insulating films that make up the multilayer wiring structure of semiconductor elements, build-up layers or core layers that make up circuit boards, and other applications in semiconductors.

<Dielectric properties of polymers>
A toluene solution (resin concentration 30 wt%) of polyhexylnorbornene (pHexNB, Mw: 100,000) and polymer 1 below mixed in the ratio shown in Figure 1 was applied to a substrate, and the coating was dried at 60°C for 15 to 30 minutes and then at 90°C for 15 to 30 minutes to obtain a film with a thickness of 100 μm. The dielectric loss tangent of the resulting film at 10 GHz was measured using a cavity resonator method. The results are shown in Figure 1.
(Polymer 1)
Polymer of Example 2 represented by the following general formula (NB/VNB, p:q=3:5, Mw: 2200)

The film containing the thermosetting resin of the present invention in Example 2 at a predetermined concentration was excellent in low dielectric properties, and it was confirmed that the thermosetting resin of the present invention is excellent in low dielectric properties.
When a curable resin composition containing the thermosetting resin of Example 2 and a radical polymerization initiator and the like was prepared and a cured product (film) was obtained from the resin composition, it was expected that the contained thermosetting resin would be cured and the vinyl groups would be consumed, resulting in an even better low dielectric property.

Claims (6)

A resin film-forming material containing a thermosetting resin,
The thermosetting resin is
A structural unit a represented by the following general formula (1),
A structural unit b represented by the following general formula (2),
Including,
the total amount of the structural units a and b in all structural units is 80 mol % or more;
the molar ratio of the structural unit b to the structural unit a (b/a) is 0.1 or more and 4 or less;
A resin film-forming material having a weight average molecular weight of 500 or more and 10,000 or less, and a solubility in toluene at 25°C of 30 wt% or more .
(In general formula (1), R ¹ , R ² , R ³ and R ⁴ represent hydrogen atoms , and n is 0. )
(In general formula (2), Q represents a vinyl group, a butenyl group, or a hexenyl group , and m is 0, 1, or 2.) 2. The resin film forming material according to claim 1 , wherein the melting temperature of the thermosetting resin is 50°C or higher and 250°C or lower. a thermosetting resin;
an organic solvent;
A resin varnish comprising:
The thermosetting resin is
A structural unit a represented by the following general formula (1),
A structural unit b represented by the following general formula (2),
Including,
the total amount of the structural units a and b in all structural units is 80 mol % or more;
the molar ratio of the structural unit b to the structural unit a (b/a) is 0.1 or more and 4 or less;
A resin varnish having a weight average molecular weight of 500 or more and 10,000 or less, and a solubility in toluene at 25°C of 30 wt% or more .
(In general formula (1), R ¹ , R ² , R ³ and R ⁴ represent hydrogen atoms, and n is 0.)
(In general formula (2), Q represents a vinyl group, a butenyl group, or a hexenyl group, and m is 0, 1, or 2.) The resin varnish according to claim 3, wherein the organic solvent comprises one or more selected from the group consisting of acetone, ethyl acetate, cyclohexane, heptane, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, N-methylpyrrolidone, propylene glycol monomethyl ether, methyl ether acetate, toluene, cyclohexanone, methyl ethyl ketone, and methyl isobutyl ketone . The resin varnish according to claim 3 , wherein the thermosetting resin is contained in an amount of 5% by mass or more and 50% by mass or less based on 100% by mass of the resin varnish. a thermosetting resin;
a radical polymerization initiator;
A curable resin composition comprising:
The thermosetting resin is
A structural unit a represented by the following general formula (1),
A structural unit b represented by the following general formula (2),
Including,
the total amount of the structural units a and b in all structural units is 80 mol % or more;
the molar ratio of the structural unit b to the structural unit a (b/a) is 0.1 or more and 4 or less;
A curable resin composition having a weight average molecular weight of 500 or more and 10,000 or less, and a solubility in toluene at 25°C of 30 wt% or more .
(In general formula (1), R ¹ , R ² , R ³ and R ⁴ represent hydrogen atoms, and n is 0.)
(In general formula (2), Q represents a vinyl group, a butenyl group, or a hexenyl group, and m is 0, 1, or 2.)