Underfill material, cured product, semiconductor package, and method for manufacturing same

Abstract

The purpose of the present invention is to provide an underfill material excellent in permeability and heat dissipation performance in a narrow gap and a large area, a cured product, a semiconductor package, and a method for manufacturing the same. Specifically, the present invention provides an underfill material which is composed of an epoxy resin composition that contains (A) an epoxy resin, (B) a curing agent and (C) an inorganic filler, wherein the inorganic filler (C) contains a component other than silica, the average particle diameter of the inorganic filler (C) is 0.01 µm-5.0 µm, and the inorganic filler (C) has two or more peaks in a particle size distribution curve.

Description

Underfill material, cured product, semiconductor package, and method for manufacturing the same

[0001] The present invention relates to an underfill material, a cured product, a semiconductor package, and a method for manufacturing the same.

[0002] Epoxy resins are used in a wide range of applications such as paints, electrical and electronic insulation materials, and adhesives because their cured products have various performances.

[0003] Currently, as a commonly used epoxy resin composition, there is a so-called two-component epoxy resin composition in which an epoxy resin and a curing agent are mixed during use.

[0004] The two-component epoxy resin composition can be cured at room temperature, but the epoxy resin and the curing agent are stored separately and, if necessary, both are weighed and mixed before use. Therefore, storage and handling are complicated. Moreover, since the usable time is limited, it cannot be mixed in large quantities in advance, resulting in an increased blending frequency and an inevitable reduction in efficiency.

[0005] For the purpose of solving the problems of such two-component epoxy resin compositions, several one-component epoxy resin compositions have been proposed so far. For example, an epoxy resin composition in which a curing agent for epoxy resin is blended with an epoxy resin can be mentioned.

[0006] For example, Patent Document 1 describes an epoxy resin using 50 μm and 75 μm alumina fillers in combination as fillers.

[0007] Further, Patent Document 2 describes an epoxy resin containing silica particles as a filler.

[0008] Japanese Patent Application Laid-Open No. 2008-106181 Japanese Patent Application Laid-Open No. 2019-077771

[0009] By the way, the requirements for recent electronic devices are diverse. Such requirements include, for example, miniaturization, high functionality, weight reduction, high functionality, and multifunctionality. More specifically, for example, in the chip mounting technology of semiconductors, further miniaturization, microminiaturization, and high density are required by fine pitch of electrode pads and pad pitches.

[0010] Also, an underfill material is used as an adhesive disposed in the gap between the chip and the substrate for the purpose of protecting the bump connection portion and the circuit surface of the chip. From the viewpoint of meeting the requirements for a higher degree of fine pitch, an underfill material that penetrates into a narrower gap is required.

[0011] Furthermore, in recent years, not only the requirement for fine pitch but also the requirement for a larger area of semiconductor chips has been progressing, so there is a possibility that the penetration time of the underfill material increases. Therefore, as the underfill material, it is also required that the viscosity change is small in the high-temperature environment during penetration and during storage. Also, with the miniaturization, small size, and high density of electronic device equipment, a large amount of electrical energy is input into a narrow area, and rapid heat generation that causes performance degradation and deterioration occurs, so high heat dissipation performance is also required.

[0012] As described above, for the latent curing agent constituting the one-component epoxy resin composition, it is required to achieve both good curability and storage stability after mixing with the epoxy resin. Furthermore, good permeability and heat dissipation performance for fine regions such as between densely packed fibers such as carbon fibers and glass fibers, and narrow gap portions of electronic components are also required.

[0013] In the above Patent Document 1, since the average particle size of the filler is large, there is room for improvement in permeability in a narrow gap and a large area.

[0014] In the above Patent Document 2, since silica particles with low thermal conductivity are used at a high content as the filler, there is room for improvement in heat dissipation performance.

[0015] The present invention has been made in view of the above problems, and the problem to be solved by the present invention is to provide an underfill material, a cured product, a semiconductor package, and a method for manufacturing the same, which are excellent in permeability and heat dissipation performance in a narrow gap and a large area.

[0016] The present invention includes the following embodiments: <1> An underfill material comprising an epoxy resin composition containing (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, wherein (C) the inorganic filler contains components other than silica, the average particle size of (C) the inorganic filler is 0.01 μm or more and 5.0 μm or less, and (C) the inorganic filler has two or more peaks in the particle size distribution curve. <2> The underfill material according to <1>, wherein the content of particles with a particle size greater than 5 μm in (C) the inorganic filler is 1 volume% or less. <3> The underfill material according to <1> or <2>, wherein the arrival time when evaluated by the following penetration evaluation method is less than 500 seconds. Method for evaluating permeability: Two glass plates, each containing two 25 μm thick copper foils spaced 10 mm apart, are placed on a hot plate. When the temperature of the glass plates reaches 110°C, the underfill material is dripped into the openings of the two glass plates, and the time required for it to penetrate 20 mm through the openings is measured. This time is defined as the arrival time. <4> The underfill material according to any one of <1> to <3>, wherein the (C) inorganic filler contains one or more selected from the group consisting of alumina, aluminum nitride, boron nitride, and silicon carbide. <5> The underfill material according to any one of <1> to <4>, wherein the (C) inorganic filler contains alumina. <6> The underfill material according to any one of <1> to <5>, wherein the (C) inorganic filler contains one or more selected from the group consisting of aluminum nitride, boron nitride, and silicon carbide, and alumina. <7> The underfill material according to any one of <1> to <6>, wherein the inorganic filler (C) has at least two peaks in the particle size distribution curve, with the first peak being between 0.10 μm and less than 0.30 μm, and the second peak being between 0.30 μm and less than 5.0 μm. <8> The underfill material according to any one of <1> to <7>, wherein, among the two or more peaks in the particle size distribution curve of the inorganic filler (C), when the peak particle diameter of the largest peak is Pa μm and the peak particle diameter of the smallest peak is Pb μm, the Pa / Pb ratio is 1.5 to 13.0.<9> The underfill material according to any one of <1> to <8>, wherein the (A) epoxy resin comprises one or more epoxy resins having a solubility parameter (SP value) of 15.0 or more and 20.0 or less. <10> The underfill material according to any one of <1> to <9>, wherein the (C) inorganic filler is surface-modified with an epoxysilane compound. <11> The underfill material according to any one of <1> to <10>, wherein the content of the (C) inorganic filler is 70.0 to 90.0% by mass with respect to the total amount of the epoxy resin composition. <12> The underfill material according to any one of <1> to <11>, further comprising (D) silica. <13> The underfill material according to <12>, wherein the average particle size of the (D) silica is 0.01 μm or more and 1.5 μm or less. <14> The underfill material according to <12> or <13>, wherein the ratio of the content of (C) inorganic filler to (D) silica is 99:1 to 80:20. <15> A cured product of the underfill material according to any one of <1> to <14>. <16> The alpha dose is 0.0020 cph / cm. ２ The cured product described in <15> below. <17> A semiconductor package comprising the cured product described in <15> or <16>. <18> A method for manufacturing a semiconductor package, comprising the step of manufacturing a semiconductor package using an underfill material described in any of <1> to <14>. <19> A method for manufacturing a semiconductor package, comprising the step of impregnating an underfill material described in any of <1> to <14> into a gap of 25 μm or less, and the step of curing the underfill material.

[0017] According to the present invention, it is possible to provide an underfill material, a cured product, and a semiconductor package and a method for manufacturing the same that have excellent penetration and heat dissipation performance in narrow gaps and large areas.

[0018] The embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail below.

[0019] The following embodiments are illustrative examples for explaining the present invention and are not intended to limit the present invention to the following content. The present invention can be implemented by modifying it as appropriate without departing from its spirit. In this specification, when "~" is used to express a value with numerical values ​​or physical properties enclosed before and after it, it is used to include the values ​​before and after it.

[0020] In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0021] In this specification, when groups (atomic groups) are not explicitly labeled as substituted or unsubstituted, the term includes both substituted and unsubstituted groups. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups.

[0022] ≪Underfill Material≫ The underfill material of this embodiment consists of the following epoxy resin composition. The underfill material of this embodiment, consisting of the following epoxy resin composition, exhibits excellent penetration and heat dissipation performance in narrow gaps and large areas. From the viewpoint of further improving the above effects, it is preferable that the arrival time (time required for penetration) when evaluated by the following penetration evaluation method is less than 500 seconds, more preferably less than 400 seconds, and even more preferably less than 300 seconds. Penetration evaluation method: Two glass plates, each with two 25 μm thick copper foils sandwiched 10 mm apart, are placed on a hot plate. When the temperature of the glass plates reaches 110°C, the underfill material is dripped into the openings of the two glass plates, and the time required for it to penetrate 20 mm from the openings is measured. This time is defined as the arrival time.

[0023] ≪Epoxy Resin Composition≫ The epoxy resin composition of this embodiment contains (A) epoxy resin, (B) curing agent, and (C) inorganic filler, wherein (C) inorganic filler contains components other than silica, (C) inorganic filler has an average particle size of 0.01 μm or more and 5.0 μm or less, and (C) inorganic filler has two or more peaks in the particle size distribution curve. The epoxy resin composition may also contain (D) silica or other components as needed.

[0024] ((A) Epoxy resin) The epoxy resin composition of this embodiment contains (A) epoxy resin.(A) The epoxy resin is not particularly limited, but examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, tetrabromobisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenylbenzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, catechol type epoxy resin, N,N-diglycidylaniline type epoxy resin, ethylene oxide-added bisphenol A type epoxy resin, propylene oxide-added bisphenol Examples include bifunctional epoxy resins such as phenol A type epoxy resin, ethylene oxide-added bisphenol F type epoxy resin, p-aminophenol type epoxy resin, and propylene oxide-added bisphenol F type epoxy resin; trifunctional epoxy resins such as trisphenol type epoxy resin, N,N-diglycidylaminobenzene type epoxy resin, o-(N,N-diglycidylamino)toluene type epoxy resin, triazine type epoxy resin, ethylene oxide-added trisphenol type epoxy resin, and propylene oxide-added trisphenol type epoxy resin; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane type epoxy resin and diaminobenzene type epoxy resin; polyfunctional epoxy resins such as pentaerythritol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, naphthol aralkyl type epoxy resin, and brominated phenol novolac type epoxy resin; and alicyclic epoxy resins.(A) Epoxy resins can be used individually or in any combination and ratio of two or more types.

[0025] (A) As the epoxy resin, a single bisphenol F type epoxy resin, a combination of a bisphenol F type epoxy resin and a bisphenol A type epoxy resin, and a combination of a bisphenol F type epoxy resin and a naphthalene type epoxy resin can also be used. From the viewpoint of achieving both penetration and heat dissipation performance in narrow gaps and large areas, it is preferable that the epoxy resin (A) contains at least one selected from the group consisting of p-aminophenol type epoxy resin, bisphenol F type epoxy resin, and diaminodiphenylmethane type epoxy resin. These may be used individually or in combination of two or more. Furthermore, epoxy resins modified with isocyanates or the like can also be used in combination.

[0026] The epoxy resin composition of this embodiment may further contain an epoxy-based reactive diluent. The epoxy-based reactive diluent is not particularly limited, but examples include n-butylglycidyl ether, t-butylglycidyl ether, allylglycidyl ether, 2-ethylhexylglycidyl ether, styrene oxide, phenylglycidyl ether, cresyl glycidyl ether, p-sec-butylphenylglycidyl ether, t-butylphenylglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, 1,3-cyclohexanedimethanol diglycidyl ether, (3,4-epoxycyclohexyl)methyl-3,4-epoxycyclohexylcarboxylate, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,6-hexanediol diglycidyl Examples include ethers, neopentyl glycol diglycidyl ether, dicyclopentadiene dimethanol diglycidyl ether, vinylcyclohexene dioxide, Mitsubishi Chemical Corporation's product name: jER(registered trademark)-YX-8000D (hydrogenated bisphenol A type epoxy resin), Sakamoto Pharmaceutical Co., Ltd.'s product name: SR-8EGS, hexahydrophthalate diglycidyl ether, resorcinol diglycidyl ether, tert-butylhydroquinone diglycidyl ether, polyoxyalkylene bisphenol A diglycidyl ether, N,N-diglycidylaniline, N,N-diglycidyl-o-toluidine, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, and N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline.

[0027] The epoxy-based reactive diluent preferably contains at least one selected from the group consisting of n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and hydrogenated bisphenol A type epoxy resin. When the epoxy resin composition contains the above-mentioned epoxy-based reactive diluent, it tends to exhibit superior penetration and heat dissipation performance in narrow gaps and large areas.

[0028] (A) The epoxy resin content is not particularly limited, but is preferably 10% by mass or more and 80% by mass or less, more preferably 10% by mass or more and 75% by mass or less, and even more preferably 10% by mass or more and 70% by mass or less, based on the total amount of the epoxy resin composition. High adhesion tends to be obtained by setting the epoxy resin content within the above range.

[0029] The epoxy resin composition of this embodiment more preferably contains one or more epoxy resins among the epoxy resins described above, wherein the solubility parameter (SP value) is 15.0 or more and 20.0 or less. By containing epoxy resins with the above predetermined SP values, an epoxy resin composition with excellent injection properties without clogging can be obtained.

[0030] (SP value) In this specification, the solubility parameter (SP value) refers to the Hansen solubility parameter, which can be determined using the Hansen solubility sphere method and can be determined using HSPiP, which is HSP calculation software.

[0031] The SP value can also be expressed by dividing it into three components as follows: dispersion force term: energy due to intermolecular dispersion forces (δD), polarity term: energy due to intermolecular dipole interactions (δP), and hydrogen bond term: energy due to intermolecular hydrogen bonds (δH).

[0032] (SP value) ２ = (δD) ２ + (δP) ２ + (δH) ２

[0033] Examples of the epoxy resins mentioned above include p-aminophenol type epoxy resin (SP value: 22.7, δD: 19.2, δP: 8.8, δH: 8.3), bisphenol F type epoxy resin (SP value: 22, δD: 19.5, δP: 7.7, δH: 6.5), 1,6-hexanediol diglycidyl ether (SP value: 19.39, δD: 16.90, δP: 7.60, δH: 5.70), and 2-ethylhexylglycidyl ether (SP value: 17.36, δD: 16.20, δP: 4.60, δH: 4.20). Examples include 1,4-cyclohexanedimethanol diglycidyl ether (SP value: 19.7, δD: 17.4, δP: 7.4, δH: 5.7), hydrogenated bisphenol A type epoxy resin (YX8000D, SP value: 18.76, δD: 17.40, δP: 5.70, δH: 4.10), n-butylglycidyl ether (SP value: 18.3, δD: 16.4, δP: 6.0, δH: 5.5), and diaminodiphenylmethane type epoxy resin (SP value: 22.3, δD: 19.6, δP: 7.3, δH: 7.7).

[0034] In the epoxy resin used in the epoxy resin composition of this embodiment, the preferred ranges for each are as follows: the lower limit of the SP value is preferably 15.0 or higher, more preferably 15.5 or higher; the upper limit of the SP value is preferably 20.0 or lower, more preferably 19.5 or lower. The lower limit of the dispersion force term (δD) in the SP value is preferably 13.0 or higher, more preferably 14.0 or higher; and the upper limit of δD is preferably 18.0 or lower, more preferably 17.5 or lower. By having the SP value and δD in the SP value within the above ranges, the epoxy resin composition exhibits excellent viscosity and viscosity stability. As a result, the amount of inorganic filler can be increased, and the cured product tends to have excellent thermal conductivity.

[0035] (B) Curing agent The epoxy resin composition of this embodiment contains (B) a curing agent.

[0036] (B) The curing agent is not particularly limited, but examples include amine-based curing agents, amide-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, active ester-based curing agents, catalytic curing agents, microencapsulated latent curing agents, thiol-based curing agents, and decomposition-type latent curing agents. Among these, amine-based curing agents are preferred from the viewpoint of curability. (B) One of these curing agents can be used alone, or two or more can be used in any combination and ratio.

[0037] (Amine-based curing agents) Examples of amine-based curing agents include, but are not limited to, aliphatic amine compounds, aromatic amine compounds, amine adducts, etc.

[0038] Aliphatic amine compounds include, but are not limited to, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, 1,2-diaminocyclohexane, and the like.

[0039] Examples of aromatic amine compounds include, but are not limited to, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, 4,4'-methylenebis[N-(1-methylpropyl)aniline], trimethylenebis(4-aminobenzoate), polytetramethylene oxide-di-p-aminobenzoate, KAYAHARD A-A (manufactured by Nippon Kayaku), EtaCure 100 Plus (curing agent containing diethyltoluenediamine, manufactured by Mitsui Chemicals Fine), and EtaCure 300 (curing agent containing dimethylthiotoluenediamine, manufactured by Mitsui Chemicals Fine).

[0040] An amine adduct is any adduct having at least an amine structure. An adduct is defined as a product obtained by the addition of two or more molecules. As amine adducts, various amine compounds listed above as amine compounds and reaction products of the epoxy resin, epoxy reactive diluent, or other compounds that can react with amine compounds can be applied.

[0041] Examples of compounds that can react with amine compounds include alcohol compounds, alkyl halides, isocyanate compounds, and ester compounds.

[0042] The alcohol compounds are not particularly limited, but examples include aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, butanol, t-butanol, pentanol, hexanol, heptanol, and octanol, and ether-type alcohols having a polyethylene glycol structure. These may be used individually or in combination of two or more.

[0043] Regarding alkyl halides, there are no particular limitations, but examples include alkyl fluorides, alkyl chlorides, alkyl bromides, and alkyl iodides. More specifically, examples include chloromethane, chloroethane, chloropropane, chlorobutane, chloropentane, chlorohexane, chloroheptane, chlorooctane, chlorononane, chlorodecane, alkyl chlorides having ether functional groups, alkyl bromides, bromomethane, bromoethane, bromopropane, bromobutane, bromopentane, bromohexane, bromoheptane, bromooctane, bromononane, bromodecane, alkyl bromides having ether functional groups, iodomethane, iodoethane, iodopropane, iodobutane, iodopentane, iodohexane, iodoheptane, iodooctane, iodononane, iododecane, and alkyl iodides having ether functional groups.

[0044] The isocyanate compound is not particularly limited, and any isocyanate compound described later can be used.

[0045] The ester compounds are not particularly limited, but examples include monocarboxylic acid ester compounds and dicarboxylic acid ester compounds. Specific examples of monocarboxylic acid ester compounds include methyl lactate, ethyl lactate, methyl mandelate, methyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl valerate, isovalerate, methyl pivalate, methyl heptanoate, methyl octanoate, methyl acrylate, methyl methacrylate, methyl crotate, methyl isocrotonate, methyl benzoyl methyl, 2-methoxybenzoylmethyl, 3-methoxybenzoylmethyl, 4-methoxybenzoylmethyl, 2-ethoxybenzoylmethyl, and 4-t-butoxybenzoylmethyl. Alternatively, ethyl esters, propyl esters, etc., may be used. Specific examples of dicarboxylic acid ester compounds include dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl tartrate, dimethyl glutarate, dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethyl azelaate, dimethyl sebacate, dimethyl maleate, dimethyl fumarate, dimethyl itaconate, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, dimethyl 1,3-acetonedicarboxylate, and diethyl 1,3-acetonedicarboxylate. Alternatively, cyclic esters may be used. Specific examples of cyclic esters include α-acetolactone, β-propionlactone, γ-butyrolactone, δ-valerolactone, γ-valerolactone, and ε-caprolactone.

[0046] In the case where the epoxy resin composition of this embodiment contains an amine adduct as a curing agent (B), it is preferable that it contains a secondary amine compound obtained by an addition reaction of a primary amine. The addition reaction is preferably a reaction in which the epoxy resin or epoxy-based reactive diluent adds to the amine, which improves the compatibility between the epoxy resin and the curing agent and reduces voids during chip flow.

[0047] (B) When the curing agent contains an amine adduct, the amine adduct preferably contains an aromatic amine adduct (A-2) which is a reaction product of an aromatic amine compound (A-1) represented by the following formula (1), the following formula (2) or the following formula (3), the aromatic amine compound (A-1), and a reactive compound having a functional group capable of reacting with the aromatic amine compound (A-1).

[0048]

[0049] In formula (1), R α and R β each independently represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, a and b are each independently an integer of 0 to 4, and X represents a divalent organic group or a single bond.

[0050]

[0051] In formula (2), R γ and R δ each independently represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, c and d are each independently an integer of 1 to 4, and Y represents a divalent organic group or a single bond.

[0052]

[0053] In formula (3), R ε represents a monovalent organic group having 1 to 20 carbon atoms or a halogen, and e is an integer of 1 to 4.

[0054] By including each of the above configurations, the curing agent (B) of the present embodiment tends to be excellent in permeability and to achieve both high curability and storage stability at a higher level after being mixed with the (A) epoxy resin.

[0055] <Aromatic amine compound (A-1)> The aromatic amine compound (A-1) is represented by formula (1), the following formula (2) or the following formula (3).

[0056]

[0057] In formula (1), R α and R βEach of the following independently represents a monovalent organic group or halogen having 1 to 20 carbon atoms, a and b are each independently integers from 0 to 4, and X represents a divalent organic group or single bond.

[0058] R α and R β In this, the monovalent organic group having 1 to 20 carbon atoms is preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. a and b are each independently preferably integers from 0 to 2, and more preferably 0 or 1. Examples of divalent organic groups include divalent organic groups having one or more aromatic rings, divalent organic groups without aromatic rings, -O-, -CO-, -C(=O)O-, and -SO ２ Examples include - and -C(=O)NH-. The divalent organic group having one or more aromatic rings is preferably a divalent organic group having one aromatic ring, and more preferably a divalent organic group having one benzene ring.

[0059] Examples of aromatic amine compounds represented by formula (1) include, for example, 4-aminophenyl-4-aminobenzoate (APAB), 2-methyl-4-aminophenyl-4-aminobenzoate, 3-methyl-4-aminophenyl-4-aminobenzoate, 2-fluoro-4-aminophenyl-4-aminobenzoate, 3-fluoro-4-aminophenyl-4-aminobenzoate, 3-methyl-4-aminophenyl-3-methyl-4-aminobenzoate, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, and 1,3-bis(3-aminophenoxy). Examples include benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, etc., and it is preferable to use one or more selected from the group consisting of these.

[0060] Among the above, from the viewpoint of having superior permeability and heat dissipation after mixing with epoxy resin, and achieving both curability and storage stability, the aromatic amine compound represented by formula (1) preferably has -O-, -CO-, -C(=O)O-, or -C(=O)NH- as X, preferably -CO-, -C(=O)O-, or -C(=O)NH-, and more preferably -C(=O)O-.

[0061]

[0062] In formula (2), R γ and R δ Each of the following independently represents a monovalent organic group or halogen having 1 to 20 carbon atoms, c and d are each independently integers from 1 to 4, and Y represents a divalent organic group or single bond.

[0063] R γ and R δ In this, the monovalent organic group having 1 to 20 carbon atoms is preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. c and d are each independently preferably integers from 0 to 2, and more preferably 0 or 1. Note that the aromatic amine compound represented by formula (2) is a compound other than the aromatic amine compound represented by formula (1). Therefore, in Y of formula (2), the divalent organic group may be a divalent organic group that does not have an aromatic ring.

[0064] Examples of aromatic amine compounds represented by formula (2) include, for example, m-tolidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, bis(4-amino-3,5-dimethylphenyl)methane, 4,4'-diamino-3,3'-5,5'-tetraethyldiphenylmethane, and others. It is preferable to use one or more selected from the group consisting of these compounds. Among the above, 3,3'-diethyl-4,4'-diaminodiphenylmethane is more preferred as the aromatic amine compound represented by formula (2) from the viewpoint of achieving both curability and storage stability after mixing with epoxy resin.

[0065]

[0066] In formula (3), R ε R represents a monovalent organic group or halogen with 1 to 20 carbon atoms, and e is an integer from 1 to 4. ε In this, the monovalent organic group having 1 to 20 carbon atoms is preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 3 carbon atoms. e is preferably an integer from 1 to 3, and more preferably 1 or 2.

[0067] Examples of aromatic amine compounds represented by formula (3) include, for example, diethyltoluenediamine (2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene) and dimethylthiotoluenediamine, and it is preferable to use one or more selected from the group consisting of these. Among the above, from the viewpoint of achieving both curability and storage stability after mixing with epoxy resin, it is preferable to use at least one selected from the group consisting of diethyltoluenediamine (2,4-diamino-3,5-diethyltoluene and 2,6-diamino-3,5-diethyltoluene) and dimethylthiotoluenediamine as the aromatic amine compound represented by formula (3).

[0068] <Aromatic Amine Adduct (A-2)> Aromatic amine adduct (A-2) is a reaction product of an aromatic amine compound (A-1) and a reactive compound having a functional group that can react with aromatic amine compound (A-1).

[0069] (Reactive Compounds) Reactive compounds have functional groups that can react with aromatic amine compounds (A-1). Examples of such functional groups include -C(=O)OC(=O)- groups, carboxyl groups, sulfo groups, isocyanate groups, carbonyl groups, epoxy groups, fluoro groups, chloro groups, bromo groups, and iodine groups.

[0070] The reactive compound is preferably at least one compound selected from the group consisting of acid anhydrides, acid dianhydrides, carboxylic acid compounds, sulfonic acid compounds, isocyanate compounds, urea compounds, epoxy compounds, and alkyl halogenated compounds.

[0071] Examples of acid anhydrides include phthalic anhydride, trimellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0072] Examples of acidic dianhydrides include pyromellitic anhydride.

[0073] Examples of carboxylic acid compounds include succinic acid, adipic acid, sebacic acid, phthalic acid, and dimer acid.

[0074] Examples of sulfonic acid compounds include ethanesulfonic acid and p-toluenesulfonic acid.

[0075] Examples of isocyanate compounds include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aliphatic triisocyanates, and polyisocyanates. Examples of aliphatic diisocyanates include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of alicyclic diisocyanates include isophorone diisocyanate, 4-4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,3-bis(2-isocyanatopropyl-2yl)cyclohexane. Examples of aromatic diisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, and 1,5-naphthalene diisocyanate. Examples of aliphatic triisocyanates include 1,3,6-triisocyanate methylhexane and 2,6-diisocyanatohexanoate-2-isocyanatoethyl. Examples of polyisocyanates include polymethylene polyphenyl polyisocyanate and polyisocyanates derived from the above diisocyanate compounds. Examples of polyisocyanates derived from the above diisocyanates include isocyanurate-type polyisocyanates, burette-type polyisocyanates, urethane-type polyisocyanates, allohanate-type polyisocyanates, and carbodiimide-type polyisocyanates.

[0076] Examples of urea compounds include urea, methylurea, dimethylurea, ethylurea, and t-butylurea.

[0077] The epoxy compound used may be a monoepoxy compound, a polyvalent epoxy compound, or a mixture thereof. Examples of monoepoxy compounds include ethyl glycidyl ether, n-butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexoate, and glycidyl benzoate.

[0078] Examples of polyvalent epoxy compounds include bisphenol-type epoxy compounds obtained by glycidylating bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, tetrachlorobisphenol A, and tetrafluorobisphenol A; epoxy compounds obtained by glycidylating divalent phenols such as biphenol, dihydroxynaphthalene, and 9,9-bis(4-hydroxyphenyl)fluorene; epoxy compounds obtained by glycidylating trisphenols such as 1,1,1-tris(4-hydroxyphenyl)methane and 4,4-(1-(4-(1-(4-hydroxyphenyl)-1-methylethyl)phenyl)ethylidene)bisphenol; and epoxy compounds obtained by glycidylating tetrakisphenols such as 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane. Examples of compounds include: novolac-type epoxy compounds obtained by glycidylating novolacs such as phenol novolac, cresol novolac, bisphenol A novolac, brominated phenol novolac, and brominated bisphenol A novolac; aliphatic ether-type epoxy compounds obtained by glycidylating polyhydric alcohols such as glycerin and polyethylene glycol; ether ester-type epoxy compounds obtained by glycidylating hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid; ester-type epoxy compounds obtained by glycidylating polycarboxylic acids such as phthalic acid and terephthalic acid; glycidyl-type epoxy compounds such as epoxy compounds obtained by glycidylating amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol, and epoxy compounds obtained by glycidylating amine-type epoxy compounds such as triglycidyl isocyanurate; and alicyclic epoxy compounds such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate.

[0079] The alkyl halide compound is not particularly limited, and any of the alkyl halide compounds described above can be used.

[0080] (Amide-based curing agents) Examples of amide-based curing agents include, but are not limited to, dicyandiamide and its derivatives, such as guanidine compounds, compounds obtained by adding acid anhydrides to amine compounds, and hydrazide compounds.

[0081] Examples of hydrazide compounds include, but are not limited to, succinate dihydrazide, adipic acid dihydrazide, phthalate dihydrazide, isophthalate dihydrazide, terephthalate dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, phenylaminopropionic acid hydrazide, and maleate dihydrazide.

[0082] Examples of guanidine compounds include, but are not limited to, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, and toluylguanidine.

[0083] (Phenol-based curing agents) Examples of phenol-based curing agents include, but are not limited to, phenol novolac resins, cresol novolac resins, phenol aralkyl resins, cresol aralkyl resins, naphthol aralkyl resins, biphenyl-modified phenol resins, biphenyl-modified phenol aralkyl resins, dicyclopentadiene-modified phenol resins, aminotriazine-modified phenol resins, naphthol novolac resins, naphthol-phenol cocondensed novolac resins, naphthol-cresol cocondensed novolac resins, allyl acrylphenol resins, and the like.

[0084] (Acid anhydride-based curing agents) Examples of acid anhydride-based curing agents include, but are not limited to, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0085] (Activated Ester-Based Curing Agent) As the activated ester compound constituting the activated ester-based curing agent, activated ester compounds disclosed in Japanese Patent Application Publication No. 2004-277460 may be used, or commercially available compounds may be used. Commercially available activated ester compounds are not limited to the following, but are preferred, for example, those containing a dicyclopentadienyldiphenol structure, acetylated phenol novolacs, and benzoylated phenol novolacs, and are more preferred, with those containing a dicyclopentadienyldiphenol structure being particularly preferred. Examples of compounds containing a dicyclopentadienyldiphenol structure are not limited to the following, but are examples, EXB9451, EXB9460, EXB9460S, HPC-8000-65T (manufactured by DIC Corporation), DC808 as an acetylated phenol novolac (manufactured by Japan Epoxy Resin Co., Ltd.), and YLH1026 as a benzoylated phenol novolac (manufactured by Japan Epoxy Resin Co., Ltd.).

[0086] (Catalytic curing agent) Examples of catalytic curing agents include, but are not limited to, cationic thermosetting catalysts and BF3-amine complexes.

[0087] (Microencapsulated latent curing agents) Examples of microencapsulated latent curing agents include, but are not limited to, Novacure HX-3721, HX-3722, HX-3613, HX-3921HP, HXA9322HP, and HXA-9382HP (manufactured by Asahi Kasei Corporation).

[0088] (Thiol-based curing agents) Examples of thiol-based curing agents include, but are not limited to, thiol compounds obtained by the esterification reaction of polyols such as trimethylolpropanetris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene glycol dithioglycolate, trimethylolpropanetris (β-thiopropionate), pentaerythritol tetrakis (β-thiopropionate), and dipentaerythritol poly(β-thiopropionate) with thiol organic acids; alkyl polythiol compounds such as 1,4-butanedithiol, 1,6-hexanedithiol, and 1,10-decanedithiol; polyethers containing terminal thiol groups; polythioethers containing terminal thiol groups; thiol compounds obtained by the reaction of epoxy compounds with hydrogen sulfide; and thiol compounds having terminal thiol groups obtained by the reaction of polythiol with epoxy compounds.

[0089] (Dispersive latent curing agent) As a decomposition type latent curing agent, amineimide compounds are preferred, and examples include at least one compound (also called compound B) selected from the group consisting of compounds represented by formulas (4), (5), and (6).

[0090]

[0091]

[0092]

[0093] (In formulas (4) to (6), R １ Each independently represents a hydrogen atom, or an n-valent organic group having 1 to 15 carbon atoms, which may have a hydroxyl group, a carbonyl group, an ester bond, or an ether bond; R ２ and R ３ Each independently represents an unsubstituted or substituted alkyl, aryl, or aralkyl group having 1 to 12 carbon atoms, or is linked to form a heterocycle having 7 or fewer carbon atoms; R ４ Each of these independently represents either a hydrogen atom or an n-valent organic group having 1 to 30 carbon atoms, which may contain an oxygen atom; n represents an integer from 1 to 3. ５represents a nitrogen atom with a negative charge, R ６ (This represents a nitrogen atom with a positive charge.)

[0094] In equations (4), (5), and (6), R １ This is presumed to contribute to lowering the energy of N-N bond cleavage. ２ and R ３ It is presumed that this contributes to the lower energy level of the cleavage reaction due to steric hindrance and resulting in instability. ４ It is presumed that this contributes to suppressing the liquefaction of the compound and the decrease in the glass transition temperature of the resulting cured product. The details of each group are described below.

[0095] In equations (4), (5), and (6), R １ Each of these independently represents either a hydrogen atom or an n-valent organic group having 1 to 15 carbon atoms, which may have a hydroxyl group, a carbonyl group, an ester bond, or an ether bond.

[0096] R １ Among these, the organic group is not particularly limited, but examples include hydrocarbon groups, groups in which a hydrogen atom bonded to a carbon atom in a hydrocarbon group is substituted by a hydroxyl group or a carbonyl group, or groups in which some of the carbon atoms in a hydrocarbon group are replaced by an ester bond or an ether bond.

[0097] R １ Examples of hydrocarbon groups include linear, branched, or cyclic alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and ethylhexyl groups; alkenyl groups such as vinyl, propynyl, butynyl, pentynyl, hexynyl, octinyl, desynyl, dodecynyl, hexadecynyl, and octadecynyl groups; aryl groups such as phenyl groups; and aralkyl groups including combinations of alkyl groups and phenyl groups such as methylphenyl, ethylphenyl, and propylphenyl groups.

[0098] R １In this context, the organic group may have other substituents. Substituents are not particularly limited, but examples include halogen atoms, alkoxy groups, carbonyl groups, cyano groups, azo groups, azi groups, thiol groups, sulfo groups, nitro groups, hydroxyl groups, acyl groups, aldehyde groups, etc. １ In particular, the number of carbon atoms in the organic group is 1 to 15, preferably 1 to 12, and more preferably 1 to 7. Having the number of carbon atoms in the organic group within this range makes it easier to obtain a liquid compound with appropriate viscosity, and tends to improve the curing performance of the compound. Furthermore, having the number of carbon atoms in the organic group within this range improves the availability of raw materials.

[0099] R ２ and R ３ Each of these independently represents an unsubstituted or substituted alkyl group, aryl group, or aralkyl group having 1 to 12 carbon atoms, or they are linked together to form a heterocycle having 7 or fewer carbon atoms.

[0100] R ２ and R ３ Among these, the alkyl group having 1 to 12 carbon atoms is not particularly limited, but examples include linear alkyl groups such as methyl, ethyl, propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, and n-dodecyl groups; branched alkyl groups such as isopropyl, isobutyl, t-butyl, neopentyl, 2-hexyl, 2-octyl, 2-decyl, and 2-dodecyl groups; and cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl, and cyclododecyl groups. Furthermore, the alkyl group may include a combination of a linear alkyl group or a branched alkyl group and a cyclic alkyl group. In addition, the alkyl group may contain an unsaturated bonding group.

[0101] R ２ and R ３In this compound, the number of carbon atoms in each alkyl group is independently 1 to 12, preferably 2 to 10, and more preferably 5 to 10. Asymmetric dialkylhydrazine compounds with a low number of carbon atoms in the alkyl group (e.g., dimethylhydrazine) may exhibit hazards such as explosions, as well as toxicity to the human body. ２ and R ３ By having two or more carbon atoms in the alkyl group, it is possible to avoid using raw materials that have the above-mentioned risks of toxicity, etc. Also, R ２ and R ３ By setting the number of carbon atoms in the alkyl group to five or more, it becomes easier to obtain a liquid compound with appropriate viscosity, and the curing performance of the compound tends to improve.

[0102] R ２ and R ３ Among these, the aryl group is not particularly limited, but examples include the phenyl group and the naphthyl group.

[0103] R ２ and R ３ Among these, the aralkyl group is not particularly limited, but examples include the methylphenyl group, ethylphenyl group, methylnaphthyl group, and dimethylnaphthyl group.

[0104] Among these, R ２ and R ３ As such, an aralkyl group is preferred, and a methylphenyl group (benzyl group) is more preferred. This tends to further improve the curing performance of the compound. Note that R ２ or R ３ The number of carbon atoms in the aryl and aralkyl groups represented by the formulas is not particularly limited, but is between 6 and 20.

[0105] R ２ and R ３ Among these, substituents on alkyl groups, aryl groups, or aralkyl groups are not particularly limited, but examples include halogen atoms, alkoxy groups, carbonyl groups, cyano groups, azo groups, azi groups, thiol groups, sulfo groups, nitro groups, hydroxyl groups, acyl groups, aldehyde groups, and the like.

[0106] R ２ and R ３These groups may be linked to form a heterocycle with seven or fewer carbon atoms. The heterocycle is not particularly limited, but examples include four-membered rings such as azetidine rings; five-membered rings such as pyrrolidine rings, pyrrole rings, morpholine rings, and thiaidine rings; six-membered rings such as piperidine rings; and seven-membered rings such as hexamethyleneimine rings and azepine rings. Among these, pyrrole rings, morpholine rings, thiaidine rings, piperidine rings, hexamethyleneimine rings, and azepine rings are preferred as heterocycles, with six-membered and seven-membered rings being more preferred. Having such groups makes it easier to obtain a liquid compound and tends to improve the curing performance of the compound.

[0107] Furthermore, the substituents are not particularly limited, but for example, alkyl groups, aryl groups, or the R mentioned above. ２ and R ３ Examples of substituents in are given. Furthermore, when the heterocycle has an alkyl group as a substituent, R ６ Examples include methyl groups bonded to adjacent carbon atoms.

[0108] In equations (4), (5), and (6), R ４ R ４ Each of these independently represents either a hydrogen atom or an n-valent organic group having 1 to 30 carbon atoms, which may contain an oxygen atom. ４ Among these, the organic group is not particularly limited, but examples include hydrocarbon groups, groups in which a hydrogen atom bonded to a carbon atom in a hydrocarbon group is replaced by a hydroxyl group, a carbonyl group, or a group containing a silicon atom, and groups in which some of the carbon atoms in a hydrocarbon group are replaced by ester bonds, ether bonds, or silicon atoms. ４ Examples of hydrocarbon groups include linear, branched, or cyclic alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and ethylhexyl groups; alkenyl groups such as vinyl, propynyl, butynyl, pentynyl, hexynyl, octinyl, desynyl, dodecynyl, hexadecynyl, and octadecynyl groups; aryl groups such as phenyl groups; and aralkyl groups including combinations of alkyl groups and phenyl groups such as methylphenyl, ethylphenyl, and propylphenyl groups.

[0109] R ４ Among these, the hydrocarbon group may include bisphenol skeletons such as bisphenol A type skeleton, bisphenol AP type skeleton, bisphenol B type skeleton, bisphenol C type skeleton, bisphenol E type skeleton, and bisphenol F type skeleton. There are no particular limitations on the organic group containing the bisphenol skeleton, but examples include groups in which a polyoxyalkylene group is added to the hydroxyl group of each bisphenol skeleton.

[0110] Among these, R in equation (4) or equation (5) ４ The organic group represented is preferably an alkyl group, an alkenyl group, or an aralkyl group, more preferably an alkyl group or an alkenyl group, and even more preferably a branched alkyl group or a branched alkenyl group. These preferred groups may have substituents. Having such groups makes it easier to obtain a liquid compound with appropriate viscosity, and tends to further improve the curing performance of the compound. Furthermore, the Tg of the cured product obtained using the compound tends to improve.

[0111] R ４ In this case, the number of carbon atoms in the organic group is 1 to 30, preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 8. ４ Because the number of carbon atoms in the organic group is within the above range, a liquid compound with appropriate viscosity is easily obtained, and the curing performance of the compound tends to be further improved. Furthermore, the Tg of the cured product obtained using this compound is further improved, and R ４ The availability of raw materials is further improved by ensuring that the number of carbon atoms in the organic group within the material falls within the above range.

[0112] Among the above, R in equation (4) or equation (5) ４Preferably, the compounds consist of linear or branched alkyl groups having 3 to 12 carbon atoms, and linear or branched alkenyl groups having 3 to 6 carbon atoms. Having such groups makes it easier to obtain a liquid compound with appropriate viscosity, and tends to further improve the curing performance of the compound. From the viewpoint of controlling the curing temperature or viscosity, compound B preferably contains multiple compounds represented by formula (4), formula (5), or formula (6). It is also possible to contain multiple compounds with different structures represented by the same formula.

[0113] Particularly from the viewpoint of viscosity control, compound B preferably contains compounds represented by formulas (4) and (5). When multiple compounds represented by formulas (4), (5), or (6) are included, the content ratio is preferably such that the content of the compound represented by formula (4) is 0.1% to 99.5% by mass relative to the total amount of compounds represented by formulas (4), (5), or (6). This allows for easy control of viscosity. Compositions containing multiple compounds represented by formulas (4), (5), or (6) can be obtained by mixing multiple compounds, or by simultaneously producing multiple compounds in the compound production method described later.

[0114] The compounds represented by formula (4), formula (5), or formula (6) are not limited to the following, but can be produced by reacting ester compounds, hydrazine compounds, and glycidyl ether compounds, for example.

[0115] The ester compounds are not particularly limited, but examples include monocarboxylic acid ester compounds and dicarboxylic acid ester compounds.

[0116] Specific examples of monocarboxylic acid ester compounds include methyl lactate, ethyl lactate, methyl mandelate, methyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl valerate, isovalerate, methyl pivalate, methyl heptanoate, methyl octanoate, methyl acrylate, methyl methacrylate, methyl crotate, methyl isocrotonate, methyl benzoyl methyl, 2-methoxybenzoylmethyl, 3-methoxybenzoylmethyl, 4-methoxybenzoylmethyl, 2-ethoxybenzoylmethyl, and 4-t-butoxybenzoylmethyl. Alternatively, ethyl esters, propyl esters, etc., may be used instead.

[0117] Specific examples of dicarboxylic acid ester compounds include dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl tartrate, dimethyl glutarate, dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethyl azelaate, dimethyl sebacate, dimethyl maleate, dimethyl fumarate, dimethyl itaconate, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, dimethyl 1,3-acetonedicarboxylate, and diethyl 1,3-acetonedicarboxylate. Alternatively, cyclic esters may be used. Specific examples of cyclic esters include α-acetolactone, β-propionlactone, γ-butyrolactone, δ-valerolactone, γ-valerolactone, and ε-caprolactone. Alternatively, diethyl esters, dipropyl esters, etc., may be used.

[0118] Among these, from the viewpoint of curability and liquefaction, ethyl lactate, methyl mandelate, methyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl valerate, methyl isovalerate, methyl pivalate, methyl acrylate, methyl methacrylate, methyl crotate, methyl isocrotonate, methyl benzoylmate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl tartrate, dimethyl glutarate, dimethyl adipate, dimethyl pimelate, dimethyl suberate, dimethyl azelaate, dimethyl maleate, dimethyl fumarate, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, dimethyl 1,3-acetonedicarboxylate, diethyl 1,3-acetonedicarboxylate, γ-butyrolactone, δ-valerolactone, and γ-valerolactone are preferred as ester compounds.

[0119] The hydrazine compounds are not particularly limited, but examples include dimethylhydrazine, diethylhydrazine, methylethylhydrazine, methylpropylhydrazine, methylbutylhydrazine, methylpentylhydrazine, methylhexylhydrazine, ethylpropylhydrazine, ethylbutylhydrazine, ethylpentylhydrazine, ethylhexylhydrazine, dipropylhydrazine, dibutylhydrazine, dipentylhydrazine, dihexylhydrazine, methylphenylhydrazine, ethylphenylhydrazine, methyltolylhydrazine, ethyltolylhydrazine, diphenylhydrazine, benzylphenylhydrazine, dibenzylhydrazine, dinitrophenylhydrazine, 1-aminopiperidine, N-aminohomopiperidine, 1-amino-2,6-dimethylpiperidine, 1-aminopyrrolidine, 1-amino-2-methylpyrrolidine, 1-amino-2-phenylpyrrolidine, and 1-aminomorpholine. Among these, from the viewpoint of curing properties and liquefaction, dimethylhydrazine, dibenzylhydrazine, 1-aminopiperidine, 1-aminopyrrolidine, and 1-aminomorpholine are preferred as hydrazine compounds. Furthermore, among these, from the viewpoint of availability and safety, dibenzylhydrazine and 1-aminopiperidine are more preferred. The hydrazine compound may be used alone or in combination of two or more.

[0120] The glycidyl ether compound is not particularly limited, but for example, monofunctional monoglycidyl ether compounds, bifunctional or polyglycidyl ether compounds, etc., can be used.

[0121] Specific examples of monoglycidyl ether compounds include methyl glycidyl ether, ethyl glycidyl ether, n-butyl glycidyl ether, t-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, orthophenylphenol glycidyl ether, benzyl glycidyl ether, biphenylyl glycidyl ether, 4-t-butylphenyl glycidyl ether, t-butyldimethylsilyl glycidyl ether, and 3-[diethoxy(methyl)silyl]propyl glycidyl ether.

[0122] Specific examples of polyglycidyl ether compounds include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, butanediol glycidyl ether, hexanediol glycidyl ether, trimethylolpropane polyglycidyl ether, and glycerin polyglycidyl ether. Examples include aliphatic polyglycidyl ethers such as glycidyl ether, diglycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and sorbitol polyglycidyl ether; alicyclic polyglycidyl ether compounds such as bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, bisphenol S type diglycidyl ether, ethylene oxide-added bisphenol A type diglycidyl ether, propylene oxide-added bisphenol A type diglycidyl ether, and hydrides of these condensates; and aromatic polyglycidyl ether compounds such as resorcinol diglycidyl ether.

[0123] Among these, from the viewpoint of curability and liquefaction, methyl glycidyl ether, ethyl glycidyl ether, n-butyl glycidyl ether, t-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, t-butyldimethylsilyl glycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, butanediol glycidyl ether, hexanediol glycidyl ether, trimethylolpropane polyglycidyl ether, bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, ethylene oxide-added bisphenol A type diglycidyl ether, propylene oxide-added bisphenol A type diglycidyl ether, polyethylene glycol diglycidyl ether, and 1-phenoxy-1,4-(oxyranylmethoxy)-3,6,9,12-tetraoxatetradecane are preferred as glycidyl ether compounds.

[0124] Furthermore, epoxy resins having an ether structure are preferred from the viewpoint of adhesion. Specific examples include polyethylene glycol diglycidyl ether and 1-phenoxy-1,4-(oxyranylmethoxy)-3,6,9,12-tetraoxatetradecane. The glycidyl ether compound may be used alone or in combination of two or more.

[0125] The amounts of ester compounds, hydrazine compounds, and glycidyl ether compounds added to the reaction system can be determined based on the molar ratio of functional groups. The amount of ester groups in the ester compound is preferably 0.8 to 3.0 moles, more preferably 0.9 to 2.8 moles, and even more preferably 0.95 to 2.5 moles, per mole of the primary amine in the hydrazine compound. Similarly, the amount of glycidyl groups in the glycidyl ether compound is preferably 0.8 to 2.0 moles, more preferably 0.9 to 1.5 moles, and even more preferably 0.95 to 1.4 moles, per mole of the primary amine in the hydrazine compound.

[0126] By controlling the amount of glycidyl groups of the glycidyl ether compound added per mole of the primary amine in the hydrazine compound, a composition containing the compound represented by formula (5) can be produced simultaneously. Specifically, the amount of glycidyl groups of the glycidyl ether compound is preferably 0.1 to 3.0 moles, more preferably 0.3 to 2.0 moles, and even more preferably 0.5 to 1.0 moles, per mole of the primary amine in the hydrazine compound. In the above-described method for producing the compound and composition, a solvent may be used from the viewpoint of ensuring that the reaction proceeds uniformly.

[0127] The solvent is not particularly limited, but examples include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, butanol, and t-butyl alcohol; and ethers such as tetrahydrofuran and diethyl ether.

[0128] The reaction temperature is preferably 10 to 100°C, and more preferably 40 to 90°C. A reaction temperature of 10°C or higher tends to accelerate the reaction and improve the purity of the resulting compound. Furthermore, a reaction temperature of 90°C or lower efficiently suppresses the polymerization reaction between glycidyl ether compounds, which also tends to improve the purity of the compound.

[0129] The reaction time is preferably 1 hour to 168 hours, more preferably 1 hour to 96 hours, and even more preferably 1 hour to 48 hours. After the reaction is complete, the reaction product can be purified by known purification methods such as washing, extraction, recrystallization, and column chromatography. For example, the reaction solution dissolved in an organic solvent can be washed with water, and then the organic layer can be heated under atmospheric pressure or reduced pressure to remove unreacted raw materials and organic solvents from the reaction solution and recover the target compound. The target compound can also be recovered by purification using column chromatography. The solvent used for the washing described above is not particularly limited as long as it can dissolve the residue of the raw materials, but 1-hexane, 1-pentane, and cyclohexane are preferred from the viewpoint of yield, purity, and ease of removal.

[0130] The organic solvent used in the extraction described above is not particularly limited as long as it can dissolve the target compound, but from the viewpoint of yield, purity, and ease of removal, ethyl acetate, dichloromethane, chloroform, carbon tetrachloride, toluene, diethyl ether, and methyl isobutyl ketone are preferred, and the use of ethyl acetate, chloroform, toluene, and methyl isobutyl ketone is more preferred.

[0131] For column chromatography, known packing materials such as alumina and silica gel can be used. Furthermore, known developing solvents such as ethyl acetate, dichloromethane, chloroform, carbon tetrachloride, tetrahydrofuran, diethyl ether, acetone, methyl isobutyl ketone, acetonitrile, methanol, ethanol, and isopropanol can be used individually or in combination.

[0132] In the epoxy resin of the present invention, (B) the curing agent is preferably such that n in formulas (5) and (6) is 2 or 3. This improves the crosslinking density during curing, allowing for the production of a tough cured product, and improving adhesion and reliability.

[0133] In the epoxy resin composition of this embodiment, the content of (B) curing agent is not particularly limited, but is preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 14% by mass or less, and even more preferably 3% by mass or more and 13% by mass or less, relative to the total amount of the epoxy resin composition. When the content of (B) cured product is within the above range, the curability of the epoxy resin composition tends to be improved.

[0134] ((C) Inorganic Filler) The epoxy resin composition of this embodiment includes (C) an inorganic filler. Note that (C) an inorganic filler includes components other than silica. That is, (C) an inorganic filler excludes (D) silica, which will be described later.

[0135] (C) There are no particular limitations on the inorganic filler, but examples include powders such as calcium carbonate, clay, alumina such as aluminum oxide, silicon nitride, silicon carbide, boron nitride, calcium silicate, potassium titanate, aluminum nitride, beryllia, zirconia, zircon, forsterite, steatite, spinel, mullite, titania, or beads made by shaping these into spheres. (C) The inorganic filler can be used individually from among these, or two or more in any combination and ratio.

[0136] From the viewpoint of achieving both thermal conductivity and viscosity when used as an epoxy resin composition, it is preferable that (C) the inorganic filler contains one or more selected from the group consisting of alumina, aluminum nitride, boron nitride, and silicon carbide, and it is particularly preferable that it contains alumina.

[0137] Furthermore, from the viewpoint of fluidity, it is preferable that (C) the inorganic filler contains one or more selected from the group consisting of aluminum nitride, boron nitride, and silicon carbide, and alumina. (C) The inorganic filler may contain three or more types of fillers.

[0138] In the epoxy resin composition of this embodiment, the content of (C) inorganic filler is preferably 70.0 to 90.0% by mass of the total amount of the epoxy resin composition. More preferably 72.0 to 85.0% by mass, even more preferably 74.0 to 83.0% by mass, and particularly preferably 75.0 to 82.5% by mass. When the inorganic filler content is 70.0% by mass or more, it tends to be easier to obtain the effect of reducing the coefficient of thermal expansion and improving the thermal conductivity. When the inorganic filler content is 90.0% by mass or less, it tends to suppress the increase in viscosity of the epoxy resin composition and improve fluidity, permeability, and dispensability. In particular, from the viewpoint of improving thermal conductivity, a higher inorganic filler content is preferable.

[0139] In this embodiment, even if the content of (C) inorganic filler is increased as described above, it is possible to maintain the epoxy resin composition at a low viscosity.

[0140] (C) The average particle size of the inorganic filler is 0.01 μm or more and 5.0 μm or less. Preferably it is 0.10 μm or more and 1.5 μm or less, more preferably 0.2 μm or more and 1.4 μm or less, and particularly preferably 0.3 μm or more and 1.3 μm or less. Including an inorganic filler with an average particle size of 0.01 μm or more improves dispersibility in the epoxy resin, makes it less likely for thixotropic properties to be imparted to the epoxy resin composition, and tends to improve the flow characteristics of the epoxy resin composition. On the other hand, including an inorganic filler with a particle size of 5.0 μm or less tends to suppress the settling of the inorganic filler in the epoxy resin composition, and improves the permeability to fine gaps and fluidity of the epoxy resin composition, which suppresses the generation of voids and unfilled portions and tends to improve heat dissipation performance. The average particle size refers to the average particle size D50 defined by the median diameter, and can be measured by appropriately selecting and using a diffraction / scattering particle size distribution analyzer and a dynamic light scattering (DLS) particle size analyzer according to the average particle size of the object to be measured, as described in the examples below. The dispersion medium used during measurement can be any dispersion medium that can be suitably dispersed by surface treatment of the inorganic filler (C), for example, in the case of an inorganic filler (C) that has been surface-treated with epoxysilane, an organic solvent such as THF is suitably used as the dispersion medium.

[0141] The inorganic filler (C) of this embodiment has two or more peaks in its particle size distribution curve. In this specification, a particle size distribution curve refers to a distribution curve with particle size on the horizontal axis and frequency on the vertical axis. For example, when two types of inorganic fillers, each having a single peak, are used, the particle size distribution curve of the inorganic fillers as a whole has two peaks. If the peaks of the two types of inorganic fillers are close together, the two peaks appearing in the particle size distribution curve will partially overlap, but generally the position of the peaks can be identified as inflection points. However, this embodiment is not limited to using two types of inorganic fillers; a single type of inorganic filler may also result in a particle size distribution curve with two or more peaks, or two or more types of inorganic fillers may be used to result in a particle size distribution curve with two or more peaks. The presence of peaks in the particle size distribution curve can be confirmed by measurement using a diffraction / scattering particle size distribution analyzer or a dynamic light scattering particle size analyzer, as described in the examples below.

[0142] The inorganic filler (C) of this embodiment has two or more peaks in the particle size distribution curve, which improves its dispersibility in epoxy resin, makes it less likely to impart thixotropic properties to the epoxy resin composition, and tends to improve the flow characteristics of the epoxy resin composition. Furthermore, it tends to suppress the settling of the inorganic filler in the epoxy resin composition, and improves the penetration into fine voids and fluidity of the epoxy resin composition, which suppresses the generation of voids and unfilled areas and tends to improve heat dissipation performance.

[0143] The peaks in the particle size distribution curve are not particularly limited, but it is preferable that, among two or more peaks, the first peak exists between 0.10 μm and less than 0.30 μm, and the second peak exists between 0.30 μm and less than 5.0 μm. The presence of peaks in the particle size distribution curve within these ranges tends to allow for a balance between thermal conductivity and viscosity when used in an epoxy resin composition. It is more preferable that the first peak in the particle size distribution curve exists between 0.15 μm and less than 0.30 μm, and the second peak exists between 0.30 μm and 1.3 μm, and even more preferable that the first peak exists between 0.20 μm and less than 0.30 μm, and the second peak exists between 0.30 μm and 1.0 μm.

[0144] Furthermore, from the viewpoint of improving the permeability and fluidity into fine gaps of the epoxy resin composition, it is more preferable that the first peak in the particle size distribution curve is between 0.15 μm and less than 0.30 μm, and the second peak is between 0.40 μm and 4.5 μm, and even more preferable that the second peak is between 0.50 μm and 4.0 μm, and the second peak is between 1.0 μm and 3.5 μm.

[0145] In this specification, the position of the peak in the particle size distribution curve can also be described as the position of the peak top. That is, in the particle size distribution curve, although not particularly limited, it is preferable that the peak top of the first peak (hereinafter also referred to as the first peak top) is at least between 0.10 μm and less than 0.30 μm, and the peak top of the second peak (hereinafter also referred to as the second peak top) is at least between 0.30 μm and 1.5 μm, it is more preferable that the peak top of the first peak is at least between 0.15 μm and less than 0.30 μm, and the peak top of the second peak is at least between 0.30 μm and 1.3 μm, and it is even more preferable that the peak top of the first peak is at least between 0.20 μm and less than 0.30 μm, and the peak top of the second peak is at least between 0.30 μm and 1.0 μm. When the peak tops of the first and second peaks are within the above ranges in the particle size distribution curve, it tends to be possible to achieve both high thermal conductivity and viscosity when used as an epoxy resin composition.

[0146] Furthermore, from the viewpoint of improving the permeability and fluidity into fine gaps of the epoxy resin composition, it is more preferable that the first peak top exists at least between 0.15 μm and less than 0.30 μm, and the second peak top exists at least between 0.40 μm and 3.5 μm, and it is even more preferable that the second peak top exists at least between 0.50 μm and 3.5 μm, and the second peak top exists at least between 1.0 μm and less than 3.5 μm.

[0147] In the particle size distribution curve, when the peak particle diameter of the peak top with the largest particle size among two or more peak tops is Paμm and the peak particle diameter of the peak top with the smallest particle size is Pbμm, it is preferable that Pa / Pb is between 1.5 and 13.0. This tends to improve fluidity. It is preferable that Pa / Pb is between 1.5 and 9.0, and even more preferable that Pa / Pb is between 1.5 and 6.0.

[0148] In this embodiment, (C) the content of particles with a particle size greater than 5 μm in the inorganic filler is preferably 1 volume% or less. When the content of particles with a particle size greater than 5 μm is 1 volume% or less, the penetration into fine gaps tends to be better. The content of particles with a particle size greater than 5 μm is more preferably 0.8 volume% or less, even more preferably 0.6 volume% or less, and particularly preferably 0.5 volume% or less. The lower limit of the content of particles with a particle size greater than 5 μm is not particularly limited, but may be 0 volume%. The content of particles with a particle size greater than 5 μm can be measured using a diffraction / scattering particle size distribution analyzer or a particle size analyzer using dynamic light scattering by the method described in the examples below. The method for adjusting the content of particles with a particle size greater than 5 μm in the inorganic filler is not particularly limited, but examples include a method of cutting coarse particles by passing the powder through a precision mesh or filter, or a method of cutting coarse particles by air flow classification.

[0149] (D) Silica The epoxy resin composition of this embodiment preferably further contains (D) silica from the viewpoint of fluidity. Examples of (D) silica include fused silica and crystalline silica. One of these types of (D) silica can be used alone, or two or more types can be used in any combination and ratio. However, (D) silica excludes the (C) inorganic filler described above.

[0150] In the epoxy resin composition of this embodiment, the total content of (C) inorganic filler and (D) silica is not particularly limited, but is preferably 75 to 90% by mass of the total amount of the epoxy resin composition. More preferably 78.5 to 89% by mass, and even more preferably 79 to 88% by mass. Setting the total content of (C) inorganic filler and (D) silica to 75% by mass or more of the total amount of the epoxy resin composition tends to easily yield effects of reducing the coefficient of thermal expansion and improving thermal conductivity. Setting the total content of (C) inorganic filler and (D) silica to 90% by mass or less of the total amount of the epoxy resin composition tends to suppress the increase in viscosity of the epoxy resin composition, resulting in good fluidity, permeability, and dispensability. In particular, from the viewpoint of improving temperature cycle resistance, a higher lower limit for the total content of (C) inorganic filler and (D) silica is preferable.

[0151] When the epoxy resin composition of this embodiment contains (D) silica, the ratio of the content of (C) inorganic filler to (D) silica is not particularly limited, but is preferably 99:1 to 80:20, more preferably 98:2 to 83:17, and even more preferably 97:3 to 85:15. When the ratio of the content of (C) inorganic filler to (D) silica is less than 99:1, the thermal conductivity tends to be improved, and when the ratio of the content of (C) inorganic filler to (D) silica is greater than 80:20, the fluidity tends to be improved.

[0152] The average particle size of (D) silica is not particularly limited, but is preferably 0.01 μm or more and 1.5 μm or less, the upper limit of the average particle size of (D) silica is more preferably 1.4 μm or less, and even more preferably 1.3 μm or less. The lower limit of the average particle size of (D) silica is more preferably 0.02 μm or more. Setting the average particle size of (D) silica to 1.5 μm or less tends to suppress the settling of inorganic fillers in the epoxy resin composition, and also tends to improve the permeability and fluidity into fine gaps of the epoxy resin composition, thereby suppressing the occurrence of voids and unfilled portions. The average particle size of (D) silica can be measured using a diffraction / scattering particle size distribution analyzer or a particle size analyzer using dynamic light scattering by the method described in the examples below.

[0153] (C) The inorganic filler and / or (D) silica may be surface-treated. The surface treatment agent is not particularly limited, but for example, it may be surface-treated using a silane coupling agent. Examples of silane coupling agents include aminosilane coupling agents, epoxysilane coupling agents, phenylsilane coupling agents, alkylsilane coupling agents, alkenylsilane coupling agents, alkynylsilane coupling agents, haloalkylsilane coupling agents, siloxane coupling agents, hydrosilane coupling agents, silazane coupling agents, alkoxysilane coupling agents, chlorosilane coupling agents, (meth)acrylicsilane coupling agents, aminosilane coupling agents, isocyanuratesilane coupling agents, ureidosilane coupling agents, mercaptosilane coupling agents, sulfidosilane coupling agents, and isocyanatesilane coupling agents. From the viewpoint of the fluidity of the epoxy resin composition, it is preferable that (C) the inorganic filler and / or (D) silica are surface-modified with an epoxysilane compound.

[0154] (Other Components) The epoxy resin composition of this embodiment may further contain other compounding agents as needed, such as curing accelerators, flame retardants, silane coupling agents, mold release agents, and pigments. These can be appropriately selected as long as the effects of this embodiment can be obtained. The flame retardant is not particularly limited, but examples include halides, phosphorus-containing compounds, nitrogen-containing compounds, and inorganic flame retardants.

[0155] (Epoxy Resin Composition) The viscosity (η1) of the epoxy resin composition of this embodiment at 100°C is not particularly limited, but from the viewpoint of fluidity over a wide range, 1.0 to 0.01 Pa·s is preferred, 0.9 to 0.05 Pa·s is more preferred, and 0.8 to 0.10 Pa·s is even more preferred. Here, the viscosity (η1) at 100°C refers to the viscosity measured 5 minutes after the sample temperature of the epoxy resin composition itself reaches 100°C.

[0156] The viscosity (η2) of the epoxy resin composition of this embodiment, measured 60 minutes after the sample temperature of the epoxy resin composition itself reaches 100°C, is not particularly limited, but from the viewpoint of fluidity over a wide range, it is preferably 0.01 Pa·s to 4.50 Pa·s, more preferably 0.01 Pa·s to 4.00 Pa·s, and even more preferably 0.01 Pa·s to 3.50 Pa·s.

[0157] In this embodiment, the viscosity increase ratio (η2 / η1), which is the ratio of the viscosity (η1) measured 5 minutes after the sample temperature of the epoxy resin composition reaches 100°C to the viscosity (η2) measured 60 minutes after the sample temperature of the epoxy resin composition reaches 100°C, is preferably 1.0 to 40.0, more preferably 1.0 to 30, more preferably 1.0 to 15, and even more preferably 1.0 to 5.0 times. By setting it within the above range, excellent fluidity over a wide range is achieved.

[0158] The above range of viscosity can be controlled, for example, by selecting (B) a suitable type and combination of curing agents. For example, the viscosity tends to decrease when using aromatic amine curing agents, and when using amine adducts, the viscosity tends to decrease when aromatic amines are added with epoxy-based reactive diluents. Furthermore, the viscosity tends to decrease when decomposition-type latent curing agents are used in combination with these. More specifically, the viscosity can be controlled, for example, by using a combination of an amine compound or amine adduct containing aromatic rings, ester groups, sulfonyl groups, etc. in its structure and an amine imide compound.

[0159] The viscosity (η1) and viscosity (η2) described above are measured by dropping the epoxy resin composition onto a measuring plate and measuring the viscosity (η1) 5 minutes after the sample temperature reaches 100°C, and the viscosity (η2) 60 minutes after that, using a rheometer (e.g., HAAKE® MARS (trade name), manufactured by Thermo Scientific) (measurement conditions: aluminum cone plate, R = 20 mm, shear rate 20 ( / sec)). From the measured viscosity (η1) and viscosity (η2), the viscosity increase ratio (η2 / η1) can be calculated. For specific measurement methods, please refer to the examples.

[0160] The epoxy resin composition of this embodiment preferably has a reaction rate of 80% to 100% when cured at 165°C, preferably 84% to 100%, more preferably 90% to 100%, and even more preferably 95% to 100%. Within this range, excellent adhesion and reliability are achieved.

[0161] The reaction rate can be controlled, for example, by the type of curing agent used. Examples of highly reactive curing agents include aromatic amine curing agents, amine adducts, and decomposition-type latent curing agents. The reaction rate can be controlled to be higher by using these, or by combining multiple types of other curing agents, or by increasing the amount added.

[0162] The curing rate when the resin composition of this embodiment is cured at 165°C can be calculated, for example, by using EXSTER6000 (product name, Hitachi High-Tech Science Co., Ltd.) to raise the temperature from 25°C to 300°C at a rate of 5°C / min and calculating the total amount of heat generated in the temperature range of 100°C to 250°C. The calculation formula is as follows: For specific measurement methods, please refer to the examples. Heat generation A: DSC peak heat generation of the epoxy resin composition Heat generation B: DSC peak heat generation of the cured epoxy resin composition Reaction rate (%) = 100 × (Heat generation A - Heat generation B) ÷ Heat generation A

[0163] The components of the epoxy resin composition of this embodiment can be identified by using known methods for analyzing the composition of chemical mixtures. For example, although not limited to the following examples, one method involves appropriately diluting the epoxy resin composition with a solvent, separating the components by utilizing the different solubility of each component such as epoxy resin, curing agent, pigment, and dye, and then analyzing each component by various chromatographic methods. For the analysis of epoxy resin components, separation can be performed using separation methods such as liquid chromatography (LC) or gel permeation chromatography (GPC) based on differences in affinity to the solvent and molecular weight, and then the mixing ratio can be estimated and analyzed using identification methods such as nuclear magnetic resonance spectroscopy (NMR) or field desorption mass spectrometry (FD / MS). When determining the parameters applied in this embodiment, it is suitably possible to use this method to confirm the composition of compositions with known mixing ratios and to identify the composition of compositions with unknown mixing ratios.

[0164] <Method for Manufacturing Epoxy Resin Composition> The epoxy resin composition of this embodiment can be manufactured, for example, by dry blending the components contained in the epoxy resin composition of this embodiment, or by adjusting them using equipment normally used for mixing polymer substances. Examples of mixing equipment include kneading equipment such as Banbury mixers, Laboplast mills, single-screw extruders, and twin-screw extruders. Preferably, the resin composition is obtained by stirring and mixing the components contained in the resin composition of this embodiment in a rotary-revolving mixer (for example, "ARE-310" (product name) manufactured by Thinky Co., Ltd.), and then kneading with a three-roll mixer. Alternatively, it is preferable to prepare the epoxy resin composition by first mixing and stirring (A) epoxy resin and (B) curing agent, then dispersing (C) inorganic filler therein to prepare a dispersion, stirring and mixing with a rotary-revolving mixer, and then kneading with a three-roll mixer.

[0165] <Applications of the Epoxy Resin Composition> The epoxy resin composition and cured product of this embodiment are useful as adhesives, encapsulants, fillers, insulating materials, sealing materials, prepregs, etc. As adhesives, they are useful as liquid adhesives, film adhesives, die bonding materials, etc. As encapsulants, they are useful as solid encapsulants, liquid encapsulants, film encapsulants, etc., and as liquid encapsulants, they are useful as underfill materials, potting materials, dam materials, etc. As insulating materials, they are useful as insulating adhesive films, insulating adhesive pastes, solder resists, etc.

[0166] <<Adhesive>> The adhesive of this embodiment includes the epoxy resin composition of this embodiment. The epoxy resin composition of this embodiment can be suitably used as an adhesive.

[0167] ≪Cured Product≫ The cured product of the underfill material or epoxy resin composition of this embodiment is obtained by curing the underfill material or epoxy resin composition by heating or the like.

[0168] The alpha radiation dose of the underfill material or the cured epoxy resin composition of this embodiment is not particularly limited, but is 0.0020 cph / cm². ２ Preferably, the alpha dose is 0.0020 cph / cm². ２ The following factors tend to make semiconductor packages using cured materials less prone to malfunctions even during long-term use: Alpha dose is 0.0015 cph / cm². ２ It is more preferable that the following is the case: 0.0010 cph / cm² ２ It is even more preferable that the following conditions are met: The lower limit of the alpha dose of the underfill material or the cured epoxy resin composition is not particularly limited, but may be below the detection limit, and is preferably 0 cph / cm². ２ That concludes the explanation. The alpha radiation dose of the underfill material or the cured epoxy resin composition can be measured using an alpha radiation counter. The alpha radiation dose of the cured product in this embodiment can be measured by the method described in the examples below.

[0169] <<Semiconductor Package>> The semiconductor package of this embodiment includes the cured product of this embodiment. The cured product of this embodiment can be suitably used as a semiconductor package.

[0170] ≪Method for Manufacturing Semiconductor Packages≫ The method for manufacturing semiconductor packages according to this embodiment includes the step of manufacturing a semiconductor package using the underfill material or epoxy resin composition of this embodiment. The step of manufacturing a semiconductor package using the underfill material or epoxy resin composition of this embodiment may also include the step of preparing the underfill material or epoxy resin composition of this embodiment. The step of manufacturing a semiconductor package using the underfill material or epoxy resin composition of this embodiment may be a step of manufacturing a semiconductor package by appropriately molding the prepared underfill material or epoxy resin composition and heating and curing it at a predetermined temperature and time.

[0171] Another embodiment of the semiconductor package manufacturing method includes the steps of impregnating the underfill material of this embodiment into a gap (void) of 25 μm or less, and curing the underfill material. This manufacturing method is preferable because it tends to better utilize the characteristics of the underfill material of this embodiment, such as excellent penetration and heat dissipation performance in narrow gaps and large areas. In this manufacturing method, the gap refers to, for example, the gap between the chip or semiconductor element and the substrate. The lower limit of the gap is not particularly limited and may be 0.1 μm or more.

[0172] More specifically, an example of how to infuse the underfill material of this embodiment into the gap between a substrate and a semiconductor element will be given. By heating the substrate constituting one side of the gap to, for example, 70 to 130°C, and applying the underfill material of this embodiment to one end of the semiconductor element constituting the other side of the gap, the underfill material of this embodiment can be infiltrated into the gap between the substrate and the semiconductor element by capillary action. In this case, the substrate may be tilted or a pressure difference may be created inside and outside the gap in order to shorten the time required for the underfill material of this embodiment to infuse. After the underfill material of this embodiment has infiltrated into the gap, the substrate may be heated at a predetermined temperature for a predetermined time, for example, 80 to 200°C for 0.2 to 6 hours, to heat-cur the underfill material of this embodiment and seal the gap.

[0173] The present invention will be described below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples.

[0174] <Evaluation> (1) Measurement and evaluation of viscosity increase (η2 / η1) For the epoxy resin compositions obtained in the examples and comparative examples described later, the dynamic viscosity η'-temperature curve was obtained when the epoxy resin composition was heated using a rheometer (HAAKE MARS, manufactured by Thermo Scientific) at a constant temperature of 100°C, oscillation mode (f=1Hz), and shear rate of 20 ( / sec). From the obtained elastic viscosity η-time curve, viscosity η1 (100°C, 5 mins) was obtained by averaging the viscosity values ​​from 4.95 mins to 5.05 mins after the start of measurement, and viscosity η2 (100°C, 60 mins) was obtained by averaging the viscosity values ​​from 59.95 mins to 60.05 mins after the start of measurement. The viscosity increase was calculated using the following formula. The viscosity increase ratio (η² / η¹) = viscosity η² ÷ viscosity η¹. The measurement start time was 10 seconds after the epoxy resin composition was dropped onto a hot plate that had reached 100°C and the epoxy resin composition was sandwiched between measurement plates. A lower viscosity increase ratio indicates better stability at high temperatures. The obtained viscosity increase ratio was evaluated according to the following evaluation criteria. [Evaluation Criteria] A: Viscosity increase ratio was less than 3.0 times. B: Viscosity increase ratio was 3.0 times or more and less than 10.0 times. C: Viscosity increase ratio was 10.0 times or more and less than 40.0 times. D: Viscosity increase ratio was 40.0 times or more.

[0175] (2) Measurement and Evaluation of Reaction Rate The epoxy resin compositions obtained in the examples and comparative examples described later were heated from 25°C to 300°C at a rate of 1°C / min using a thermal analyzer EXSTER6000 (Hitachi High-Tech Science Co., Ltd.), and the total amount of heat generated was calculated from the observed exothermic peaks. Furthermore, the epoxy resin compositions were placed in a small high-temperature chamber (manufactured by ESPEC) at 165°C for 2 hours, and the cured product was measured in the same manner, and the reaction rate was calculated using the following formula: Heat generation A: DSC peak heat generation of the epoxy resin composition Heat generation B: DSC peak heat generation of the cured epoxy resin composition Reaction rate (%) = 100 × (Initial heat generation A - Heat generation B after curing) ÷ Initial heat generation A The obtained reaction rate was evaluated according to the following evaluation criteria. [Evaluation Criteria] A: The reaction rate was 95% or higher. B: The reaction rate was 90% or higher but less than 95%. C: The reaction rate was 85% or higher but less than 90%. D: The reaction rate was less than 85%.

[0176] (3) Measurement and evaluation of permeability Two glass plates, each containing two 25 μm thick copper foils spaced 10 mm apart, were placed on a hot plate. When the temperature of the glass plates reached 110°C, the epoxy resin composition was dripped into the openings of the two glass plates, and the time required for it to penetrate 20 mm through the openings was measured. This time was defined as the arrival time. A shorter time required for penetration indicates better permeability, and better permeability indicates better injection into larger areas. The obtained times were evaluated according to the following evaluation criteria. [Evaluation criteria] A: Arrival time was less than 300 seconds. B: Arrival time was 300 seconds or more and less than 400 seconds. C: Arrival time was 400 seconds or more and less than 500 seconds. D: Arrival time was 500 seconds or more.

[0177] (4) Measurement and Evaluation of Thermal Conductivity Test specimens were prepared by cutting a cured epoxy resin composition, which had been cured at 165°C for 2 hours, into 40 mm x 40 mm pieces. The test specimens and thermal conductivity measuring device (product name: SS-H40, manufactured by Bethel Co., Ltd.) were used to measure the thermal conductivity according to ASTM D5470-16. The obtained thermal conductivity was evaluated according to the following evaluation criteria. [Evaluation Criteria] A: Thermal conductivity was 1.3 W / m·k or higher. B: Thermal conductivity was less than 1.3 W / m·k and 1.1 W / m·k or higher. C: Thermal conductivity was less than 1.1 W / m·k and 0.9 W / m·k or higher. D: Thermal conductivity was less than 0.9 W / m·k.

[0178] (5) Measurement of average particle size (D50) The inorganic filler or epoxy resin composition was dissolved in THF (tetrahydrofuran) so that the amount of inorganic filler was 0.1% by mass, and the average particle size (D50) was determined using a diffraction / scattering particle size distribution analyzer (LA-920) manufactured by Horiba, Ltd. For inorganic fillers with an average particle size of 0.1 μm or less, the average particle size (D50) was determined using the above samples with a multi-sample nanoparticle measurement system (nanoSAQLA) manufactured by Otsuka Electronics Co., Ltd.

[0179] (6) Measurement of alpha dose A cured epoxy resin composition, cured at 165°C for 2 hours, was cut into 40 mm x 40 mm pieces to prepare test specimens. Six test specimens were obtained (total 1008 cm²). ２The alpha dose was measured using a low-level alpha measuring device LACS-4000M (applied voltage 1.9 kV, PR-10 gas (argon:methane = 9:1) 100 m / min, effective counting time 88 h).

[0180] (Examples 1-23 and Comparative Example 1) Each component shown in Tables 1 and 2 was placed in a plastic stirring container in the amounts shown in Tables 1 and 2. This mixture was stirred and mixed using a rotating / revolving mixer (Sinky Co., Ltd. "ARE-310" (product name)), and then kneaded with a three-roll mixer to prepare an epoxy resin composition.

[0181] Each of the resulting epoxy resin compositions was poured into a Teflon (registered trademark) mold and heated at 165°C for 2 hours to produce a cured product.

[0182] The obtained epoxy resin compositions were evaluated as described above, and the results are shown in Tables 1 and 2.

[0183] <Ingredients> The ingredients listed in the table below are as follows: ((A) Epoxy resin) A-1: ​​jER(registered trademark)-630LSD (p-aminophenol type epoxy resin, manufactured by Mitsubishi Chemical Corporation, SP value: 22.7) A-2: EPICLON(registered trademark) EXA-830CRP (bisphenol F type epoxy resin, manufactured by DIC Corporation, SP value: 20.1) A-3: YED-216 (1,6-hexanediol diglycidyl ether, manufactured by Mitsubishi Chemical Corporation, SP value: 19.4) A-4: 2-EH (2-ethylhexylglycidyl ether, SP value: 17.4) A-5: Showfree(registered trademark) CDMDG (1,4-cyclohexanedimethanol diglycidyl ether, manufactured by Resonaq Corporation, SP value: 19.7) A-6: jER(registered trademark)-YX8000D (hydrogenated bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, SP value: 18.8) A-7: DY-BP (n-butylglycidyl ether, manufactured by Yokkaichi Synthetic Co., Ltd., SP value: 18.3) A-8: jER(registered trademark)-604 (diaminodiphenylmethane type epoxy resin, manufactured by Mitsubishi Chemical Corporation, SP value: 22.3)

[0184] ((B) Curing agents for epoxy resins) B-1A: Etacure 100 Plus (curing agent containing diethyltoluenediamine, manufactured by Mitsui Chemicals Fine, Inc.) B-1B: Etacure 300 (curing agent containing dimethylthiotoluenediamine, manufactured by Mitsui Chemicals Fine, Inc.) B-1C: MBDA (4,4'-methylenebis[N-(1-methylpropyl)aniline], manufactured by Kumiai Chemical Industry Co., Ltd.) B-2A: DETDA adduct-2EH (aromatic amine adduct from Synthesis Example 1) B-2B: DETDA adduct-nBGE (aromatic amine adduct from Synthesis Example 2) B-2C: DETDA adduct-ethyl (aromatic amine adduct from Synthesis Example 3) B-2D: APAB adduct-2EH (aromatic amine adduct from Synthesis Example 4) B-3A: Amine imide from Synthesis Example 5 B-3B: Aminemide from Synthesis Example 6 B-3C: Aminemide from Synthesis Example 7 B-3D: Aminemide from Synthesis Example 8

[0185] ((C) Inorganic Fillers) C-1A: Alumina filler surface-treated with 3-glycidoxypropyltrimethoxysilane (average particle size 0.25 μm, content of particles larger than 5 μm less than 0.5 vol%) C-1B: Alumina filler surface-treated with N-phenyl-3-aminopropyltrimethoxysilane (average particle size 0.25 μm, content of particles larger than 5 μm less than 0.5 vol%) C-1C: Alumina filler surface-treated with 3-glycidoxypropyltrimethoxysilane (average particle size 0.9 μm, content of particles larger than 5 μm less than 0.5 vol%, inorganic filler of Preparation Example 1) C-1D: Alumina filler surface-treated with 3-glycidoxypropyltrimethoxysilane (average particle size 0.4 μm, content of particles larger than 5 μm less than 0.5 vol%, inorganic filler of Preparation Example 2) C-1E: Alumina filler surface-treated with 3-glycidoxypropyltrimethoxysilane (average particle size 3.1 μm, content of particles larger than 5 μm less than 0.5 volume%) C-2A: Aluminum nitride filler (average particle size 0.9 μm, content of particles larger than 5 μm less than 0.5 volume%) C-3A: Silicon carbide filler (average particle size 1.2 μm, content of particles larger than 5 μm less than 0.5 volume%) C-4A: Boron nitride filler (average particle size 1.4 μm, content of particles larger than 5 μm less than 0.5 volume%)

[0186] (D) Silica D-1: Y50SP-C2 (average particle size 0.05 μm, content of particles larger than 5 μm less than 0.5 volume%, manufactured by Admatex Co., Ltd.)

[0187] <(C) Preparation of Inorganic Filler> [Preparation Example 1] (Inorganic Filler (C-1C)) 100 g of alumina filler (average particle size 0.9 μm, content of particles larger than 5 μm less than 0.5 vol%) and 3 g of KBM-403 (3-glycidoxypropyltrimethoxysilane) were mixed and stirred at room temperature for 10 minutes using a stirrer, and then aged for 24 hours to obtain inorganic filler (C-1C).

[0188] [Preparation Example 2] (Inorganic Filler (C-1D)) Inorganic filler (C-1D) was prepared using the same method as the preparation method for inorganic filler (C-1C) described above, except that the alumina filler with an average particle size of 0.9 μm was replaced with alumina filler with an average particle size of 0.4 μm and a content of particles larger than 5 μm of less than 0.5 volume%.

[0189] <(B) Synthesis of the curing agent> [Synthesis Example 1] (Synthesis of compound (B-2A)) A 500 ml four-necked flask equipped with a reflux tubing and a stirring blade was purged with nitrogen, and 20 g of 1-butanol and 0.05 mol of EtaCure 100(+) were added and heated until the internal temperature reached 120°C. Then, using a dropping funnel, 0.025 mol of 2-ethylhexylglycidyl ether (2-EH) was added dropwise over 30 minutes. After the addition was complete, the reaction solution was heated at 120°C for 6 hours while stirring to complete the reaction. Using an evaporator, 1-butanol was removed from the obtained solution over 2 hours while maintaining the temperature at 80°C and the pressure at 15 mmHg or less, to obtain compound (B-2A). The ESI-MS measurements were 365.5 (H+) and 551.7 (H+), confirming the formation of compound (B-2A).

[0190] [Synthesis Example 2] (Synthesis of Compound (B-2B)) Compound (B-2B) was obtained by the same method as the synthesis of Compound (B-2A), except that 2-EH was replaced with butyl glycidyl ether (BGE). The ESI-MS measurements were 309.5 (H+) and 439.7 (H+), confirming the formation of Compound (B-2B).

[0191] [Synthesis Example 3] (Synthesis of Compound (B-2C)) Compound (B-2C) was obtained by the same method as the synthesis of compound (B-2A), except that 2-EH was replaced with ethyl glycidyl ether (EGE). The ESI-MS measurements were 281.2 (H+) and 383.3 (H+), confirming the formation of compound (B-2C).

[0192] [Synthesis Example 4] (Synthesis of Compound (B-2D)) A 500 ml four-necked flask equipped with a reflux condenser and stirring blade was purged with nitrogen. 20 g of 1-butanol and 0.025 mol of 4-aminophenyl 4-aminobenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was heated until the internal temperature reached 120°C. Then, using a dropping funnel, 0.025 mol of 2-ethylhexylglycidyl ether (2-EH) was added dropwise over 30 minutes. After the addition was complete, the reaction solution was heated at 120°C for 6 hours with stirring to complete the reaction. Using an evaporator, 1-butanol was removed from the obtained solution over 2 hours while maintaining the temperature at 80°C and the pressure at 15 mmHg or less, to obtain compound (B-2D). ESI-MS measurements were 359.2 (H+) and 489.3 (H+), confirming the formation of compound (B-2D).

[0193] [Synthesis Example 5] (Synthesis of Compound (B-3A)) 1.94 g (0.019 mol) of ethyl propionate and 5.00 g (0.009 mol) of polyethylene glycol diglycidyl ether were weighed into a round-bottom flask, and the flask was heated in an oil bath until it reached 90°C. Next, 1.62 g (0.016 mol) of 1-aminopiperidine was added dropwise over 15 minutes. After the addition was complete, the mixture was stirred for 4 hours while maintaining the temperature at 90°C to complete the reaction. The resulting reaction solution was concentrated under reduced pressure at 80°C to remove the by-product alcohol and unreacted starting materials by distillation, yielding the liquid product, compound (B-3A). Compound (B-3A) contains structures (B-3A-1) and (B-3A-2) as shown below, and the SP value of (B-3A-2) was 19.6.

[0194]

[0195] [Synthesis Example 6] (Synthesis of Compound (B-3B)) 3.93 g (0.038 mol) of ethyl propionate and 5.00 g (0.038 mol) of butyl glycidyl ether were weighed into a round-bottom flask, and the flask was heated in an oil bath until it reached 90°C. Next, 3.85 g (0.038 mol) of 1-aminopiperidine was added dropwise over 15 minutes. After the addition was complete, the mixture was stirred for 4 hours at 90°C to complete the reaction. The resulting reaction solution was concentrated under reduced pressure at 80°C to remove the by-product alcohol and unreacted starting materials by distillation, yielding the liquid product, compound (B-3B). Compound (B-3B) also contains structures (B-3B-1) and (B-3B-2) shown below, with the SP value of (B-3B-2) being 19.6.

[0196]

[0197] [Synthesis Example 7] (Synthesis of Compound (B-3C)) 8.77 g (0.06 mol) of dimethyl succinate, 12.02 g (0.12 mol) of 1-aminopiperidine, 22.54 g (0.12 mol) of 2-ethylhexylglycidyl ether, and 21.67 g (0.29 mol) of t-butyl alcohol were mixed to obtain a solution. This solution was reacted at 55°C for 4 days with stirring to obtain a reaction mixture. The obtained reaction mixture was concentrated under reduced pressure at 55°C to remove t-butyl alcohol, by-product alcohol, and unreacted starting materials by distillation, thereby obtaining a solid product. This product was dissolved in ethyl acetate and washed with water repeatedly using a separatory funnel to remove unreacted starting material residues. This organic layer was concentrated again under reduced pressure at 55°C to obtain a white amorphous solid compound (B-3C). Furthermore, compound (B-3C) also includes structures (B-3C-1) and (B-3C-2) shown below, with the SP value of (B-3C-2) being 18.5.

[0198]

[0199] [Synthesis Example 8] (Synthesis of Compound (B-3D)) 2.40 g (0.023 mol) of ethyl propionate and 10.57 g of Denacol EX-991L were weighed into a round-bottom flask, and the flask was heated in an oil bath until it reached 90°C. Next, 2.00 g (0.020 mol) of 1-aminopiperidine was added dropwise over 15 minutes. After the addition was complete, the mixture was stirred for 4 hours at 90°C to complete the reaction. The resulting reaction solution was concentrated under reduced pressure at 80°C to remove the by-product alcohol and unreacted starting materials by distillation, yielding the liquid product, compound (B-3D). Compound (B-3D) also contains structures (B-3D-1) and (B-3D-2) shown below, with the SP value of (B-3D-2) being 18.9.

[0200]

[0201] The compounds in Synthesis Examples 1-8 were identified by nuclear magnetic resonance (NMR) spectroscopy and infrared absorption (IR) spectroscopy. Solubility parameters (SP values) were calculated using HSPiP ver. 5, an HSP calculation software.

[0202]

[0203]

[0204] The results in Tables 1 and 2 show that, comparing Examples 1-23 with Comparative Example 1, Examples 1-23 exhibit excellent penetration, high thermal conductivity, and superior heat dissipation performance. They also demonstrate high reaction rates, excellent adhesion, and reliability. Furthermore, they exhibit low viscosity, excellent high-temperature stability, and fluidity.

[0205] Furthermore, when the cured products of Examples 1 to 23, obtained by the same method as in (4) Measurement and evaluation of thermal conductivity, were measured using an alpha-ray counter, the alpha radiation dose was found to be 0.0020 cph / cm² in all cases. ２ The following has been confirmed:

[0206] The disclosure of Japanese Patent Application No. 2024-195565, filed on 8 November 2024, is incorporated herein by reference in its entirety. Furthermore, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard had been specifically and individually indicated as being incorporated by reference.

[0207] The underfill material of the present invention exhibits excellent penetration and heat dissipation performance in narrow gaps and large areas, and has industrial applicability.

Claims

1. An underfill material comprising an epoxy resin composition containing (A) epoxy resin, (B) a curing agent, and (C) an inorganic filler, wherein (C) the inorganic filler contains components other than silica, the average particle size of (C) the inorganic filler is 0.01 μm or more and 5.0 μm or less, and (C) the inorganic filler has two or more peaks in the particle size distribution curve.

2. The underfill material according to claim 1, wherein the content of particles with a particle size greater than 5 μm in the inorganic filler (C) is 1% by volume or less.

3. The underfill material according to claim 1, wherein the time to reach the target area when evaluated by the following penetration evaluation method is less than 500 seconds. Penetration evaluation method: Two glass plates, each containing two 25 μm thick copper foils spaced 10 mm apart, are placed on a hot plate. When the temperature of the glass plates reaches 110°C, the underfill material is dripped into the openings of the two glass plates, and the time required for it to penetrate 20 mm through the openings is measured and defined as the time to reach the target area.

4. The underfill material according to claim 1, wherein the (C) inorganic filler comprises one or more selected from the group consisting of alumina, aluminum nitride, boron nitride, and silicon carbide.

5. The underfill material according to claim 1, wherein the inorganic filler (C) contains alumina.

6. The underfill material according to claim 1, wherein the (C) inorganic filler comprises one or more selected from the group consisting of aluminum nitride, boron nitride, and silicon carbide, and alumina.

7. The underfill material according to claim 1, wherein the inorganic filler (C) has at least two peaks in the particle size distribution curve, with the first peak being between 0.10 μm and less than 0.30 μm and the second peak being between 0.30 μm and less than 5.0 μm.

8. The underfill material according to claim 1, wherein, among the two or more peaks in the particle size distribution curve of the inorganic filler (C), the peak particle diameter of the largest peak is Pa μm and the peak particle diameter of the smallest peak is Pb μm, and Pa / Pb is 1.5 or more and 13.0 or less.

9. The underfill material according to claim 1, wherein the epoxy resin (A) comprises one or more epoxy resins having a solubility parameter (SP value) of 15.0 or more and 20.0 or less.

10. The underfill material according to claim 1, wherein the inorganic filler (C) is surface-modified with an epoxysilane compound.

11. The underfill material according to claim 1, wherein the content of the inorganic filler (C) is 70.0 to 90.0% by mass with respect to the total amount of the epoxy resin composition.

12. The underfill material according to claim 1, further comprising (D) silica.

13. The underfill material according to claim 12, wherein the average particle size of the (D) silica is 0.01 μm or more and 1.5 μm or less.

14. The underfill material according to claim 12, wherein the ratio of the content of (C) inorganic filler to (D) silica is 99:1 to 80:

20.

15. A cured underfill material according to any one of claims 1 to 14.

16. Alpha dose was 0.0020 cph / cm² ２ The cured product according to claim 15, which is as follows:

17. A semiconductor package comprising the cured product described in claim 15.

18. A method for manufacturing a semiconductor package, comprising the step of manufacturing a semiconductor package using an underfill material according to any one of claims 1 to 14.

19. A method for manufacturing a semiconductor package, comprising the steps of: impregnating an underfill material according to any one of claims 1 to 14 into a gap of 25 μm or less; and curing the underfill material.

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