JP7613077B2 - Resin composition and high frequency device - Google Patents

Description

The present invention relates to a resin composition and a high-frequency device.

In recent years, with the demand for electronic devices to have higher functionality and to be lighter, thinner, shorter, and smaller, electronic components have become more densely integrated and even more densely mounted, and the semiconductor packages used in these electronic devices are becoming smaller and smaller than ever before. Furthermore, the radio waves used for communication between electronic devices are becoming higher in frequency.

In order to reduce the size of semiconductor packages and accommodate high frequencies, high-dielectric epoxy resin compositions have been proposed for use in sealing semiconductor elements (see, for example, Patent Document 1).

JP 2015-36410 A

As semiconductor packages (PKGs) become smaller and more functional, development is also underway on antenna-in-package (AiP), which is a PKG that has an antenna function. By using a material with a high relative dielectric constant as the sealing material for sealing the antenna, it is possible to miniaturize the AiP.

In addition, it is desirable for the resin composition, such as the sealing material that seals the antenna, to have high fluidity from the viewpoint of moldability.

The objective of the present disclosure is to provide a resin composition capable of producing a cured product having excellent fluidity and a high dielectric constant, and a high-frequency device having a cured product obtained by curing this resin composition.

Specific means for solving the above problems include the following aspects.
<1> A resin composition for use in molding a high-frequency device having an antenna, comprising: an epoxy resin; a curing agent; a first inorganic filler containing elemental titanium; and a second inorganic filler having a peak particle size in a particle size distribution different from a peak particle size in the particle size distribution of the first inorganic filler.
<2> The resin composition according to <1>, wherein the first inorganic filler has a relative dielectric constant of 10 or more at 10 GHz.
<3> The resin composition according to <1> or <2>, wherein the content of the first inorganic filler is 60% by mass to 95% by mass based on the total amount of the first inorganic filler and the second inorganic filler.
<4> The resin composition according to any one of <1> to <3>, wherein a particle size distribution of a combination of the first inorganic filler and the second inorganic filler has at least three peaks.
<5> The second inorganic filler includes a third inorganic filler having a particle size distribution peak particle size of 0.1 μm to 5 μm, and a fourth inorganic filler having a particle size distribution peak particle size of 7 μm to 100 μm. The resin composition according to any one of <1> to <4>.
<6> The resin composition according to <5>, wherein the first inorganic filler has a peak particle size in a particle size distribution that is larger than the peak particle size of the third inorganic filler and smaller than the peak particle size of the fourth inorganic filler.
<7> The resin composition according to <5> or <6>, wherein a mass ratio of the fourth inorganic filler to the third inorganic filler (fourth inorganic filler/third inorganic filler) is 0.1 to 5.
<8> The resin composition according to any one of <1> to <7>, wherein the second inorganic filler contains at least one of alumina and silica.
<9> The resin composition according to any one of <1> to <8>, wherein the first inorganic filler includes at least one selected from the group consisting of barium titanate, calcium titanate, and strontium titanate.
<10> A resin composition comprising an epoxy resin, a curing agent, and an inorganic filler, the inorganic filler having a particle size distribution having at least three peaks, the inorganic filler comprising a first inorganic filler containing elemental titanium.
<11> The resin composition according to <10>, wherein the particle size distribution of the inorganic filler has a first peak located in a range of 0.1 μm to 5 μm, a second peak located in a range of 0.5 μm to 30 μm, and a third peak located in a range of 7 μm to 100 μm, and the value of the first peak < the value of the second peak < the value of the third peak.
<12> A high-frequency device comprising an antenna and a cured product of the resin composition according to any one of <1> to <11>.

The present disclosure provides a resin composition capable of producing a cured product having excellent fluidity and a high dielectric constant, and a high-frequency device having a cured product obtained by curing this resin composition.

In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.
In the present disclosure, the numerical ranges indicated using "to" include the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present disclosure, each component may contain multiple types of the corresponding substance. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.
In the present disclosure, the particles corresponding to each component may include multiple types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

<Resin Composition>
The resin composition of the present disclosure contains an epoxy resin, a curing agent, a first inorganic filler containing elemental titanium, and a second inorganic filler having a peak particle size in a particle size distribution different from the peak particle size in the particle size distribution of the first inorganic filler, and is a resin composition for use in molding a high-frequency device having an antenna.

The resin composition of the present disclosure contains a first inorganic filler and a second inorganic filler, and therefore it is possible to produce a cured product having excellent fluidity and a high relative dielectric constant. The reason for this is presumed to be as follows. The resin composition of the present disclosure contains a first inorganic filler containing elemental titanium, and therefore it is possible to produce a cured product having a high relative dielectric constant. Furthermore, the resin composition of the present disclosure contains two or more inorganic fillers with different peak particle sizes, and therefore it has excellent fluidity.

The resin composition of the present disclosure is not limited to a configuration containing two inorganic fillers with different peak particle sizes. For example, the first inorganic filler containing titanium element may be composed of two or more inorganic fillers containing titanium element and having different peak particle sizes, and the second inorganic filler may be composed of two or more inorganic fillers with different peak particle sizes. When the first inorganic filler contains titanium element and is composed of two or more inorganic fillers with different peak particle sizes, the second inorganic filler may have a peak particle size different from any one of the two or more inorganic fillers with different peak particle sizes in the first inorganic filler. When the second inorganic filler is composed of two or more inorganic fillers with different peak particle sizes, the first inorganic filler may have a peak particle size different from any one of the two or more inorganic fillers with different peak particle sizes in the second inorganic filler.

The resin composition of the present disclosure is a resin composition for use in molding a high-frequency device having an antenna, and is used to manufacture a resin molded product using various molding methods such as low-pressure transfer molding, injection molding, and compression molding. The resin composition of the present disclosure may be a composition used to seal an antenna. The resin composition is preferably used in semiconductor packaging applications that require both a high relative dielectric constant and a low dielectric loss tangent, and is more preferably used, for example, in an antenna-in-package (AIP).

The components constituting the resin composition are described below. The resin composition of this embodiment contains an epoxy resin, a curing agent, a first inorganic filler, and a second inorganic filler, and may contain other components as necessary.

(Epoxy resin)
The type of epoxy resin is not particularly limited as long as it has an epoxy group in the molecule.

Specific examples of epoxy resins include novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) which are obtained by epoxidizing a novolac resin obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc., under an acidic catalyst; and triphenylmethane-type phenolic resins which are obtained by condensing or co-condensing the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc., under an acidic catalyst. diphenylmethane-type epoxy resins; copolymer epoxy resins obtained by epoxidizing novolak resins obtained by co-condensing the above-mentioned phenol compounds and naphthol compounds with aldehyde compounds under an acidic catalyst; diphenylmethane-type epoxy resins which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl-type epoxy resins which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene-type epoxy resins which are diglycidyl ethers of stilbene-based phenol compounds; sulfur-containing epoxy resins which are diglycidyl ethers of bisphenol S, etc.; epoxy resins which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester-type epoxy resins which are glycidyl esters of polyvalent carboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid. glycidylamine-type epoxy resins in which active hydrogen attached to nitrogen atoms of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is replaced with a glycidyl group; dicyclopentadiene-type epoxy resins in which a co-condensed resin of dicyclopentadiene and a phenol compound is epoxidized; alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane in which an olefin bond in a molecule is epoxidized; paraxylylene-modified epoxy resins which are glycidyl ethers of paraxylylene-modified phenol resins; metaxylylene-modified epoxy resins which are glycidyl ethers of metaxylylene-modified phenol resins; terpene-modified phenol resins Terpene-modified epoxy resins are glycidyl ethers of phenol resins; dicyclopentadiene-modified epoxy resins are glycidyl ethers of dicyclopentadiene-modified phenol resins; cyclopentadiene-modified epoxy resins are glycidyl ethers of cyclopentadiene-modified phenol resins; polycyclic aromatic ring-modified epoxy resins are glycidyl ethers of polycyclic aromatic ring-modified phenol resins; naphthalene-type epoxy resins are glycidyl ethers of naphthalene ring-containing phenol resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenol resins such as phenol aralkyl resins and naphthol aralkyl resins; and the like. Furthermore, epoxy-oxidized acrylic resins and the like can also be mentioned as epoxy resins. These epoxy resins may be used alone or in combination of two or more.
From the viewpoint of heat resistance, the epoxy resin preferably contains a triphenylmethane type epoxy resin.

The epoxy equivalent (molecular weight/number of epoxy groups) of the epoxy resin is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, it is preferably 100 g/eq to 1000 g/eq, and more preferably 150 g/eq to 500 g/eq.

The epoxy equivalent of the epoxy resin is the value measured using a method conforming to JIS K 7236:2009.

When the epoxy resin is solid, its softening point or melting point is not particularly limited. From the viewpoints of moldability and heat resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability when preparing the resin composition, it is more preferably 50°C to 130°C.

The softening point or melting point of the epoxy resin is a value measured by differential scanning calorimetry (DSC) or a method conforming to JIS K 7234:1986 (ring and ball method).

From the viewpoints of strength, fluidity, heat resistance, moldability, etc., the content of the epoxy resin in the resin composition is preferably 0.5% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, and even more preferably 3% by mass to 10% by mass.

(Hardening agent)
The resin composition contains a curing agent. The curing agent may be any compound having a functional group that reacts with the epoxy group in the epoxy resin.

The curing agent is not particularly limited, and examples thereof include phenol curing agents, amine curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, blocked isocyanate curing agents, and ester curing agents. These curing agents may be used alone or in combination of two or more.

The curing agent may contain a phenolic curing agent in order to keep the dielectric tangent of the cured product low and to improve moldability.

Specific examples of phenolic hardeners include polyhydric phenolic compounds such as resorcin, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenol; novolak-type phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with aldehyde compounds such as formaldehyde, acetaldehyde, and propionaldehyde, under an acid catalyst; and novolak-type phenolic resins synthesized from the above phenolic compounds and dimethoxy-para-xylene, bis(methoxymethyl)biphenyl, etc. Examples of the phenol curing agent include aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins; paraxylylene-modified phenolic resins, metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above-mentioned phenolic compounds and dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensing or co-condensing the above-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acid catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenolic curing agents may be used alone or in combination of two or more.

The functional group equivalent of the curing agent (for example, the hydroxyl group equivalent in the case of a phenolic curing agent) is not particularly limited. From the viewpoint of the balance of various properties such as moldability, heat resistance, and electrical reliability, it is preferably 70 g/eq to 1000 g/eq, and more preferably 80 g/eq to 500 g/eq.
The functional group equivalent of the curing agent (for example, the hydroxyl group equivalent in the case of a phenolic curing agent) is a value measured by a method in accordance with JIS K 0070:1992.

When the curing agent is a solid, its softening point or melting point is not particularly limited. From the viewpoints of moldability and heat resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during production of the resin composition, it is more preferably 50°C to 130°C.

The softening point or melting point of the hardener shall be a value measured in the same manner as the softening point or melting point of the epoxy resin.

The equivalent ratio of the epoxy resin to the curing agent, i.e., the ratio of the number of functional groups in the curing agent to the number of functional groups in the epoxy resin (number of functional groups in the curing agent/number of functional groups in the epoxy resin), is not particularly limited. From the viewpoint of keeping the amount of unreacted components low, it is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the viewpoint of moldability and heat resistance, it is even more preferable to set it in the range of 0.8 to 1.2.

(Cure Accelerator)
The resin composition may contain a curing accelerator. The type of the curing accelerator is not particularly limited and can be selected depending on the type of epoxy resin or curing agent, the desired properties of the resin composition, and the like.

Examples of the curing accelerator include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; and combinations of these compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, and the like. quinone compounds such as quinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone; compounds having intramolecular polarization obtained by adding a compound having a π bond, such as diazophenylmethane; cyclic amidini such as tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, tetraphenylborate salt of 2-ethyl-4-methylimidazole, and tetraphenylborate salt of N-methylmorpholine; ammonium compounds and compounds obtained by adding isocyanates; an isocyanate adduct of DBU, an isocyanate adduct of DBN, an isocyanate adduct of 2-ethyl-4-methylimidazole, an isocyanate adduct of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide; primary phosphines such as ethylphosphine and phenylphosphine, secondary phosphines such as dimethylphosphine and diphenylphosphine, triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl.alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris organic phosphines such as tertiary phosphines such as (trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, alkyldiarylphosphine, trinaphthylphosphine, and tris(benzyl)phosphine; phosphine compounds such as complexes of the organic phosphines with organoborons; the organic phosphines or the phosphine derivatives compounds having intramolecular polarization obtained by adding a compound having a π bond, such as a quinone compound such as maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, or anthraquinone, or a compound having a π bond, such as diazophenylmethane; Halogenated phenols such as phenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodophenol, 3-iodophenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-tert-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, and 4-bromo-4'-hydroxybiphenyl. Examples of such a compound include compounds having intramolecular polarization obtained by reacting a compound and then subjecting the compound to a dehydrohalogenation process; tetra-substituted phosphonium compounds such as tetra-substituted phosphonium compounds such as tetraphenylphosphonium, tetraphenylborate salts of tetra-substituted phosphonium compounds such as tetraphenylphosphonium tetra-p-tolylborate, and salts of tetra-substituted phosphonium compounds with phenol compounds; salts of tetraalkylphosphonium compounds with partial hydrolysates of aromatic carboxylic acid anhydrides; phosphobetaine compounds; and adducts of phosphonium compounds with silane compounds.
The curing accelerators may be used alone or in combination of two or more.
Among these, particularly suitable curing accelerators include triphenylphosphine, an adduct of triphenylphosphine and a quinone compound, an adduct of tributylphosphine and a quinone compound, and an adduct of tri-p-tolylphosphine and a quinone compound.

When the resin composition contains a curing accelerator, the amount is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent). When the amount of the curing accelerator is 0.1 parts by mass or more per 100 parts by mass of the resin component, the composition tends to cure well in a short time. When the amount of the curing accelerator is 30 parts by mass or less per 100 parts by mass of the resin component, the curing speed is not too fast and a good molded product tends to be obtained.

(First inorganic filler)
The resin composition contains a first inorganic filler containing elemental titanium. The first inorganic filler may be used alone or in combination of two or more.

The first inorganic filler preferably has a relative dielectric constant of 10 or more at 10 GHz, more preferably 10 to 100, and even more preferably 30 to 100.

In the present disclosure, the relative dielectric constant at 10 GHz in the inorganic filler is a value obtained as follows. First, a resin composition consisting of 100 parts by mass of an epoxy resin (biphenyl aralkyl type epoxy resin, epoxy equivalent 274 g/eq), 74.8 parts by mass of a phenol curing agent (phenol aralkyl resin, hydroxyl group equivalent 205 g/eq), and 2 parts by mass of a 1,4-benzoquinone adduct of triphenylphosphine, an inorganic filler, and methyl ethyl ketone (MEK) are mixed, and the aforementioned resin composition is dissolved in MEK to prepare a varnish containing 75% by mass of the resin composition and the inorganic filler in total. At this time, varnishes containing 10% by volume, 20% by volume, and 30% by volume of the inorganic filler relative to the solid content excluding the solvent are prepared, respectively.
The obtained varnish was applied onto a substrate, and the substrate was dried at 100°C for 10 minutes, after which the resin film was peeled off from the substrate. The obtained resin film was molded by compression molding under the conditions of a mold temperature of 175°C, molding pressure of 6.9MPa, and curing time of 600 seconds to obtain each of the cured products for measurement. The dielectric constant at 10 GHz of each of the obtained cured products for measurement was measured, and a graph was created in which the content of the inorganic filler was plotted on the horizontal axis and the measured value of the dielectric constant was plotted on the vertical axis. From the obtained graph, a linear approximation was performed by the least squares method, and the dielectric constant when the content of the inorganic filler was 100% by volume was obtained by extrapolation, and this was taken as the "dielectric constant of the entire inorganic filler".

From the viewpoint of obtaining a cured product having a high relative dielectric constant, the first inorganic filler preferably contains at least one selected from the group consisting of barium titanate, calcium titanate, strontium titanate, zinc zirconate titanate, and titanium oxide, and more preferably contains at least one selected from the group consisting of barium titanate, calcium titanate, and strontium titanate. Of these, from the viewpoint of high sphericity and high fluidity, it is preferable that the first inorganic filler contains barium titanate.

In the first inorganic filler, the peak particle size of the particle size distribution is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 30 μm, even more preferably 2 μm to 15 μm, and particularly preferably 3 μm to 10 μm.

In this disclosure, the peak particle size of the inorganic filler can be measured as follows. The resin composition is placed in a crucible and left at 800°C for 4 hours to be incinerated. The particle size distribution of the inorganic filler obtained by incineration is determined using an imaging particle size distribution analyzer equipped with a Raman spectrometer (e.g., Morphologi 4-ID by Malvern Panalytical Co., Ltd.), and the peak particle size of the inorganic filler can be determined from the particle size distribution.

From the viewpoint of the fluidity of the resin composition, the first inorganic filler may be two or more inorganic fillers having different peak particle sizes in the particle size distribution, or may be two inorganic fillers having different peak particle sizes in the particle size distribution.

The shape of the first inorganic filler is not particularly limited, and examples of the shape include spherical, elliptical, and amorphous. The first inorganic filler may also be crushed.

The content of the first inorganic filler may be 60% by mass to 95% by mass, 70% by mass to 90% by mass, or 80% by mass to 90% by mass, based on the total amount of the first inorganic filler and the second inorganic filler. When the content of the first inorganic filler is 60% by mass or more, the relative dielectric constant tends to be higher when the resin composition is cured. When the content of the first inorganic filler is 95% by mass or less, the resin composition tends to have excellent fluidity.

The content of the first inorganic filler may be 40% by volume to 95% by volume, 50% by volume to 90% by volume, or 65% by volume to 80% by volume, based on the total amount of the first inorganic filler and the second inorganic filler. When the content of the first inorganic filler is 40% by volume or more, the relative dielectric constant tends to be higher when the resin composition is cured. When the content of the first inorganic filler is 95% by volume or less, the resin composition tends to have excellent fluidity.

(Second Inorganic Filler)
The resin composition contains a second inorganic filler having a peak particle size in a particle size distribution different from the peak particle size in the particle size distribution of the first inorganic filler. The second inorganic filler may be used alone or in combination of two or more.

The second inorganic filler may have a relative dielectric constant at 10 GHz of less than 10, less than 8, or less than 5.

The type of the second inorganic filler is not particularly limited. Specific examples include inorganic materials such as fused silica, crystalline silica, glass, alumina, talc, clay, and mica. As the second inorganic filler, an inorganic filler having a flame retardant effect may be used. Examples of inorganic fillers having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as composite hydroxides of magnesium and zinc, and zinc borate. The second inorganic filler may or may not contain titanium element.

Among the second inorganic fillers, silica such as fused silica is preferred from the viewpoint of reducing the linear expansion coefficient, and alumina is preferred from the viewpoint of high thermal conductivity. The second inorganic filler may be in the form of a powder, beads obtained by spheroidizing the powder, fibers, etc.

In the second inorganic filler, the peak particle size of the particle size distribution is preferably 0.1 μm to 100 μm, and more preferably 0.5 μm to 50 μm.

From the viewpoint of the fluidity of the resin composition, the second inorganic filler may be two or more inorganic fillers having different peak particle sizes in the particle size distribution, or may be two inorganic fillers having different peak particle sizes in the particle size distribution.

In the resin composition of the present disclosure, from the viewpoint of the fluidity of the resin composition, it is preferable that the particle size distribution of the combination of the first inorganic filler and the second inorganic filler has at least three peaks. In this case, it is sufficient that there is at least one peak derived from the first inorganic filler and at least one peak derived from the second inorganic filler.

The particle size distribution of the combination of the first inorganic filler and the second inorganic filler may be determined as follows. The particle size distribution of the first inorganic filler and the second inorganic filler may be determined using an image particle size distribution meter equipped with the above-mentioned Raman spectrometer, and the determined particle size distributions may be combined.

When the particle size distribution of the combination of the first inorganic filler and the second inorganic filler has three or more peaks, it is preferable that there is a first peak located in the range of 0.1 μm to 5 μm, a second peak located in the range of 0.5 μm to 30 μm, and a third peak located in the range of 7 μm to 100 μm, and the value of the first peak < the value of the second peak < the value of the third peak.

The first peak is preferably located in the range of 0.1 μm to 3 μm, and more preferably in the range of 0.1 μm to 2 μm.

The second peak is preferably located in the range of 2 μm to 15 μm, and more preferably in the range of 3 μm to 10 μm.

The third peak is preferably located in the range of 7 μm to 80 μm, and more preferably in the range of 10 μm to 60 μm.

When the particle size distribution of the combination of the first inorganic filler and the second inorganic filler has three or more peaks, for example, there may be one or two or more peaks originating from the first inorganic filler and two or three or more peaks originating from the second inorganic filler.

From the viewpoint of the fluidity of the resin composition, it is preferable that the second inorganic filler includes a third inorganic filler having a peak particle size of 0.1 μm to 5 μm in the particle size distribution, and a fourth inorganic filler having a peak particle size of 7 μm to 100 μm in the particle size distribution.

In the first inorganic filler, it is preferable that the peak particle size of the particle size distribution is larger than the peak particle size of the third inorganic filler and smaller than the peak particle size of the fourth inorganic filler. In this case, the first peak may be a peak derived from the third inorganic filler, the second peak may be a peak derived from the first inorganic filler, and the third peak may be a peak derived from the fourth inorganic filler.

The mass ratio of the fourth inorganic filler to the third inorganic filler (fourth inorganic filler/third inorganic filler) is preferably 0.1 to 5, more preferably 0.5 to 4, and even more preferably 1 to 3, from the viewpoint of the fluidity of the resin composition.

The total content of the first inorganic filler and the second inorganic filler is not particularly limited, and from the viewpoint of fluidity and strength, it is preferably 50% by mass to 95% by mass, more preferably 60% by mass to 95% by mass, and even more preferably 70% by mass to 90% by mass, based on the entire resin composition. When the total content of the first inorganic filler and the second inorganic filler is 50% by mass or more, the properties of the cured product, such as the relative dielectric constant, thermal expansion coefficient, thermal conductivity, and elastic modulus, tend to be further improved. When the total content of the first inorganic filler and the second inorganic filler is 95% by mass or less, the increase in viscosity of the resin composition is suppressed, and the fluidity is further improved, tending to result in better moldability.

In addition to the above-mentioned components, the resin composition may contain various additives such as coupling agents, ion exchangers, release agents, flame retardants, colorants, and stress relaxation agents, as exemplified below. In addition to the additives exemplified below, the resin composition may contain various additives known in the art, as necessary.

(Coupling Agent)
The resin composition may contain a coupling agent. From the viewpoint of increasing the adhesion between the resin component and the inorganic filler, the resin composition preferably contains a coupling agent. Examples of the coupling agent include known coupling agents such as silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, vinylsilane, and disilazane, titanium-based compounds, aluminum chelate compounds, and aluminum/zirconium-based compounds.

When the resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 parts by mass to 5 parts by mass, and more preferably 0.1 parts by mass to 2.5 parts by mass, relative to 100 parts by mass of the total of the first inorganic filler and the second inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more, the adhesion to the frame tends to be further improved. When the amount of the coupling agent is 5 parts by mass or less, the moldability of the package tends to be further improved.

(Ion exchanger)
The resin composition may contain an ion exchanger. In order to improve the moisture resistance and high-temperature storage characteristics of a high-frequency device including a cured product of the resin composition, it is preferable to contain an ion exchanger. The ion exchanger is not particularly limited, and a conventionally known ion exchanger can be used. Specifically, a hydrotalcite compound and a hydrous oxide of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth can be mentioned. The ion exchanger may be used alone or in combination of two or more kinds. Among them, hydrotalcite represented by the following general formula (A) is preferable.

Mg _(1-X) Al _X (OH) ₂ (CO ₃ ) _X/2・mH ₂ O ... (A)
(0<X≦0.5, m is a positive number)

When the resin composition contains an ion exchanger, the content is not particularly limited as long as it is an amount sufficient to capture ions such as halogen ions. For example, the content is preferably 0.1 to 30 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent).

(Release Agent)
The resin composition may contain a mold release agent from the viewpoint of obtaining good releasability from the mold during molding. The mold release agent is not particularly limited, and a conventionally known one may be used. Specific examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene, etc. The mold release agent may be used alone or in combination of two or more kinds.

When the resin composition contains a release agent, the amount is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent). When the amount of release agent is 0.01 part by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When the amount is 10 parts by mass or less, better adhesion tends to be obtained.

(Flame retardant)
The resin composition may contain a flame retardant. The flame retardant is not particularly limited, and a conventionally known one may be used. Specific examples include organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, metal hydroxides, etc. The flame retardant may be used alone or in combination of two or more kinds.

When the resin composition contains a flame retardant, the amount is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, it is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent).

(Coloring Agent)
The resin composition may contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose. The colorant may be used alone or in combination of two or more.

(Stress Relief Agent)
The resin composition may contain a stress relaxation agent. By containing a stress relaxation agent, it is possible to further reduce the warpage deformation of the package and the occurrence of package cracks. Examples of the stress relaxation agent include known stress relaxation agents (flexible agents) that are generally used. Specifically, examples of the stress relaxation agent include thermoplastic elastomers such as silicone-based, styrene-based, olefin-based, urethane-based, polyester-based, polyether-based, polyamide-based, and polybutadiene-based elastomers, rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder, and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. The stress relaxation agent may be used alone or in combination of two or more types.

Among the stress relaxation agents, silicone-based stress relaxation agents are preferred. Examples of silicone-based stress relaxation agents include those having an epoxy group, those having an amino group, and those modified with polyether. Silicone compounds such as silicone compounds having an epoxy group and polyether-based silicone compounds are more preferred. Among these, polyether-based silicone compounds are preferred from the viewpoint of reducing the dielectric tangent of the cured product and suppressing poor appearance of the cured product.

The polyether silicone compound is not particularly limited as long as it is a compound in which a polyether group is introduced into silicone, which is a polymeric compound having a main skeleton formed by siloxane bonds. The polyether silicone compound may be used alone or in combination of two or more kinds.
The polyether silicone compound may be a side-chain modified polyether silicone compound or a terminal modified polyether silicone compound. Among these, the polyether silicone compound is preferably a side-chain modified polyether silicone compound from the viewpoint of suppressing poor appearance of the cured product.

An example of the polyether silicone compound is an epoxy-polyether silicone compound. The epoxy-polyether silicone compound is not particularly limited as long as it is a compound in which a polyether group and an epoxy group are introduced into silicone, which is a polymeric compound having a main skeleton formed by siloxane bonds.
The epoxy polyether silicone compound may be a side chain modified epoxy polyether silicone compound, a terminal modified epoxy polyether silicone compound, or a side chain and terminal modified epoxy polyether silicone compound. The main skeleton of the epoxy polyether silicone compound is preferably polydimethylsiloxane. The polyether group is preferably a polyether group in which one or both of ethylene oxide and propylene oxide are polymerized.
The epoxy-polyether silicone compound is preferably a side-chain-modified epoxy-polyether silicone compound in which a polyether group (preferably a polyether group obtained by polymerizing one or both of ethylene oxide and propylene oxide) and an epoxy group are each present in the side chain of silicone (preferably polydimethylsiloxane).

When the resin composition contains a stress relaxation agent, the amount is, for example, preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the resin component (total amount of epoxy resin and curing agent).

(Method of preparing resin composition)
The method for preparing the resin composition is not particularly limited. A typical method is to thoroughly mix a predetermined amount of components with a mixer or the like, melt-knead them with a mixing roll, an extruder, or the like, cool them, and pulverize them. More specifically, for example, a method is to uniformly stir and mix a predetermined amount of the above-mentioned components, knead them with a kneader, roll, extruder, or the like that has been heated to 70°C to 140°C in advance, cool them, and pulverize them.

The resin composition is preferably solid at room temperature and normal pressure (e.g., 25°C, atmospheric pressure). When the resin composition is solid, the shape is not particularly limited, and examples include powder, granules, and tablets. When the resin composition is in tablet form, it is preferable from the viewpoint of handleability that the dimensions and mass are set to be suitable for the molding conditions of the package.

<Modification of Resin Composition>
A modified example of the resin composition of the present disclosure will be described. The modified example of the resin composition of the present disclosure is a resin composition containing an epoxy resin, a curing agent, and an inorganic filler, the particle size distribution of the inorganic filler having at least three peaks, and the inorganic filler containing a first inorganic filler containing titanium element. The modified example of the resin composition may be appropriately combined with the forms described in the above-mentioned section on the resin composition of the present disclosure.

The modified resin composition of the present disclosure is capable of producing a cured product having excellent fluidity and a high dielectric constant. The reason for this is presumably that the inclusion of the first inorganic filler containing titanium element allows the production of a cured product having a high dielectric constant, and the particle size distribution of the inorganic filler has at least three peaks, which gives the resin composition excellent fluidity.

In a modified version of the resin composition of the present disclosure, the first inorganic filler containing titanium element may contain titanium element and may be composed of three or more inorganic fillers with different peak particle sizes. Alternatively, a modified version of the resin composition of the present disclosure may contain the second inorganic filler contained in the resin composition of the present disclosure described above, and the particle size distribution of the combination of the first inorganic filler and the second inorganic filler may have at least three peaks.

In a modified version of the resin composition of the present disclosure, the particle size distribution of the inorganic filler preferably has a first peak located in the range of 0.1 μm to 5 μm, a second peak located in the range of 0.5 μm to 30 μm, and a third peak located in the range of 7 μm to 100 μm, with the first peak < the second peak < the third peak.

The modified resin composition of the present disclosure is not limited to resin compositions for use in molding high-frequency devices having antennas, but may be resin compositions for use in other applications.

<High frequency devices>
The high-frequency device of the present disclosure has an antenna and a cured product of the above-described resin composition.

The high-frequency device of the present disclosure is used, for example, when transmitting and receiving radio waves of 1 GHz or more, and preferably when transmitting and receiving radio waves of 3 GHz or more. The high-frequency device of the present disclosure may have a structure in which the cured product of the resin composition seals the antenna, or may have a structure in which the antenna is disposed on the cured product of the resin composition.

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples.

<Preparation of Resin Composition>
A resin composition was prepared by mixing the components shown below in the mixing ratios (unit: parts by mass) shown in Table 1. This resin composition was solid at room temperature and normal pressure. Also, blanks in Table 1 mean that the component was not mixed.

Epoxy resin 1: triphenylmethane type epoxy resin, epoxy equivalent 167 g/eq
Epoxy resin 2: biphenyl aralkyl type epoxy resin, epoxy equivalent 274 g/eq
Epoxy resin 3: biphenyl type epoxy resin, epoxy equivalent 192 g/eq
Phenol curing agent 1: phenol aralkyl resin, hydroxyl equivalent 205 g/eq
Phenol hardener 2: phenol novolac resin, hydroxyl equivalent 101 g/eq
Curing accelerator: 1,4-benzoquinone adduct of triphenylphosphine Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane Release agent: Montan acid ester wax Colorant: Carbon black Additive: Side chain modified epoxy Polyether modified silicone Inorganic filler 1: Spherical barium titanate with a volume average particle size (D50) of 6.5 μm (relative dielectric constant at 10 GHz: 46.3)
Inorganic filler 2: Spherical silica particles having a volume average particle size (D50) of 40 μm (large particle size silica, relative dielectric constant at 10 GHz: 3.6)
Inorganic filler 3: Spherical silica particles having a volume average particle size (D50) of 0.5 μm (small particle size silica, relative dielectric constant at 10 GHz: 3.6)
Inorganic filler 4: spherical alumina particles having a volume average particle size (D50) of 45 μm (large particle size alumina, relative dielectric constant at 10 GHz: 7.8)
Inorganic filler 5: spherical alumina particles having a volume average particle size (D50) of 0.7 μm (small particle size alumina, relative dielectric constant at 10 GHz: 7.8)

In addition, in the particle size distribution of the inorganic fillers measured using an imaging particle size distribution analyzer equipped with a Raman spectrometer, inorganic filler 1 has a peak in the range of 3 μm to 10 μm, inorganic fillers 2 and 4 have peaks larger than the peak of inorganic filler 1 and in the range of 10 μm to 60 μm, and inorganic fillers 3 and 5 have peaks in the range of 0.1 μm to 2 μm.

(Dielectric constant of inorganic filler)
The relative dielectric constant of the inorganic filler was determined as follows. First, a resin composition of 100 parts by mass of epoxy resin (biphenylaralkyl type epoxy resin, epoxy equivalent 274 g/eq), 74.8 parts by mass of phenol curing agent (phenolaralkyl resin, hydroxyl equivalent 205 g/eq), and 2 parts by mass of 1,4-benzoquinone adduct of triphenylphosphine, any one of inorganic fillers 1 to 5, and methyl ethyl ketone (MEK) were mixed, and the aforementioned resin composition was dissolved in MEK to prepare a varnish containing 75% by mass of the resin composition and inorganic filler in total. At this time, varnishes containing 10%, 20%, and 30% by volume of inorganic fillers 1 to 5 with respect to the solid content excluding the solvent were prepared.
The obtained varnish was applied onto a substrate, and the substrate was dried at 100°C for 10 minutes, after which the resin film was peeled off from the substrate. The obtained resin film was molded by compression molding under the conditions of a mold temperature of 175°C, molding pressure of 6.9MPa, and curing time of 600 seconds to obtain each of the cured products for measurement. The dielectric constant at 10 GHz of each of the obtained cured products for measurement was measured, and a graph was created in which the content of the inorganic filler was plotted on the horizontal axis and the measured value of the dielectric constant was plotted on the vertical axis. From the obtained graph, a linear approximation was performed by the least squares method, and the dielectric constant when the content of the inorganic filler was 100% by volume was obtained by extrapolation, and this was taken as the "dielectric constant of the entire inorganic filler".

(Fluidity: Spiral flow)
Using a spiral flow measurement mold conforming to EMMI-1-66, the resin composition was molded under the conditions of a mold temperature of 180° C., a molding pressure of 6.9 MPa, and a curing time of 90 seconds, and the flow distance (cm) was determined. The results are shown in Table 1.

(Gel time)
The gel time of the resin composition at 175°C was measured as follows. Specifically, 0.5 g of a sample of the resin composition was placed on a hot plate heated to 175°C, and the sample was uniformly spread into a circle of 2.0 cm to 2.5 cm at a rotation speed of 20 rpm to 25 rpm using a jig. The time from when the sample was placed on the hot plate until the sample lost its viscosity, became gelled, and could be peeled off from the hot plate was measured, and this was measured as the gel time (seconds). The results are shown in Table 1.

(Dielectric constant and dielectric loss tangent of the cured product)
The resin composition was molded using a hand press under the conditions of a mold temperature of 175°C, molding pressure of 6.9 MPa, and curing time of 600 seconds, and post-cured at 175°C for 6 hours. The plate-shaped cured product was cut into a test piece having a length of 50 mm, a width of 1 mm, and a thickness of about 0.5 mm. The relative dielectric constant and dielectric loss tangent were measured at a temperature of 25±3°C and 10 GHz using the test piece and a dielectric constant measuring device (Agilent, product name "Network Analyzer N5227A").
The results are shown in Table 1.

As shown in Table 1, the resin compositions of Examples 1 to 15 were superior in fluidity to the resin composition of Comparative Example 1.
Furthermore, it was possible to produce cured products having a relatively high dielectric constant using the resin compositions of Examples 1 to 15. For example, it is presumed that the resin compositions of Examples 1 to 15 can produce cured products having a higher dielectric constant than resin compositions using only silica particles or only alumina particles as the inorganic filler.

Claims (10)

Epoxy resin,
A hardener;
A first inorganic filler containing elemental titanium;
A second inorganic filler having a peak particle size of a particle size distribution different from the peak particle size of the particle size distribution of the first inorganic filler;
Contains
The content of the first inorganic filler is 60% by mass to 95% by mass based on the total amount of the first inorganic filler and the second inorganic filler,
the second inorganic filler is silica or alumina;
A resin composition for use in molding a high-frequency device having an antenna, wherein, with respect to the particle size distribution of the second inorganic filler, when the second inorganic filler is silica, there are two peaks derived from the second inorganic filler which is silica, and when the second inorganic filler is alumina, there are two peaks derived from the second inorganic filler which is alumina. The resin composition according to claim 1, wherein the first inorganic filler has a relative dielectric constant of 10 or more at 10 GHz. The resin composition according to claim 1 or 2 , wherein a particle size distribution of a combination of the first inorganic filler and the second inorganic filler has at least three peaks. The second inorganic filler includes a third inorganic filler having a peak particle size of 0.1 μm to 5 μm in particle size distribution, and a fourth inorganic filler having a peak particle size of 7 μm to 100 μm in particle size distribution. The resin composition according to any one of claims 1 to 3 . The resin composition according to claim 4 , wherein the peak particle size of the particle size distribution of the first inorganic filler is larger than the peak particle size of the third inorganic filler and smaller than the peak particle size of the fourth inorganic filler. The resin composition according to claim 4 or claim 5 , wherein the mass ratio of the fourth inorganic filler to the third inorganic filler (fourth inorganic filler/third inorganic filler) is 0.1 to 5. The resin composition according to any one of claims 1 to 6 , wherein the first inorganic filler comprises at least one selected from the group consisting of barium titanate, calcium titanate, and strontium titanate. Epoxy resin,
A hardener;
An inorganic filler;
The particle size distribution of the inorganic filler has at least three peaks, and the inorganic filler includes a first inorganic filler containing titanium element and a second inorganic filler having a peak particle size of the particle size distribution different from the peak particle size of the particle size distribution of the first inorganic filler ,
The content of the first inorganic filler is 60% by mass to 95% by mass based on the total amount of the first inorganic filler and the second inorganic filler,
the second inorganic filler is silica or alumina;
Regarding the peaks of the particle size distribution of the inorganic filler, when the second inorganic filler is silica, there are two peaks derived from the second inorganic filler which is silica, and when the second inorganic filler is alumina, there are two peaks derived from the second inorganic filler which is alumina . The particle size distribution of the inorganic filler has a first peak located in the range of 0.1 μm to 5 μm, a second peak located in the range of 0.5 μm to 30 μm, and a third peak located in the range of 7 μm to 100 μm, and the value of the first peak < the value of the second peak < the value of the third peak. The resin composition according to claim 8 . A high-frequency device comprising an antenna and a cured product of the resin composition according to any one of claims 1 to 9 .