Thermosetting resin composition, cured product, use thereof, and two-phase co-continuous silica structure

Abstract

The purpose of the present invention is to provide: a thermosetting resin composition that can exhibit a high elastic modulus and a low thermal expansion rate in the resulting cured product, as compared with conventional non-porous silica particles, without impairing dielectric properties possessed by the thermosetting resin; a cured product of the thermosetting resin composition; and a silica structure suitably used for the application. Specifically, the thermosetting resin composition contains a two-phase co-continuous silica structure composed of a phase having silica as a main component and an air phase. It is preferable that at least a part of the air phase of the two-phase co-continuous silica structure is filled with the thermosetting resin.

Description

Thermosetting resin composition, cured product, its applications, and two-phase continuous silica structure

[0001] The present invention relates to a thermosetting resin composition comprising a thermosetting resin and a specific silica structure.

[0002] With the increasing volume of information due to the spread of high-speed communication technologies such as 5G, advanced autonomous driving (ADAS), and generative AI, data centers and terminal information processing equipment are required to transmit information at higher speeds, with larger capacities and wider bandwidths. Therefore, in addition to miniaturizing and creating three-dimensional transistors and circuits on silicon wafers in the semiconductor front-end process, advancements in technology are needed in the back-end process (packaging) to increase the size of the substrate, thereby increasing the size of the chips that can be mounted and enabling higher density and integration. In response to these demands, 3D packages, in which multiple dissimilar semiconductor chips are mounted within a single package, have been proposed in recent years.

[0003] The purpose of integrating dissimilar chips is to speed up internal connections between chips, resulting in miniaturization of the chips themselves, wiring, and terminal spacing, while package size increases. Typically, chips are primarily composed of single-crystal silicon and are bonded to substrates primarily composed of metal or plastic via a die bond agent, and these are further protected with a encapsulant containing a curable resin. Large stresses occur within the encapsulant and other mounted components (printed circuit boards, build-up films, package substrates) or at the interface between the encapsulant and surrounding components due to differences in the properties of these components, namely thermal expansion coefficients and elastic moduli, which can cause warping, delamination, deformation, and cracking. For this reason, conventional methods have aimed to reduce thermal expansion by increasing the density of inorganic fillers such as silica particles in resin compositions containing epoxy resins, etc., used as curable resins for package substrates and encapsulants (see, for example, Patent Document 1).

[0004] To achieve high-density inorganic fillers, it is preferable to combine several types of silica particles with different particle sizes or to use silica particles with high sphericity. As a method of producing such particles, it has been reported that high-purity amorphous spherical silica particles can be synthesized and their particle size can be adjusted by burning silicon particle dust with a volume-average particle size of 5.5 μm or less and 0.01 μm or more in an oxygen-containing gas (see, for example, Patent Document 2). Alternatively, it has been disclosed that amorphous spherical silica particles suitable as semiconductor encapsulants can be obtained by ejecting crystal-crushed silica powder into a flame and spheroidizing it (see, for example, Patent Document 3).

[0005] Japanese Patent Publication No. 5-148343, Japanese Patent Publication No. 2001-106521, Japanese Patent Publication No. 2018-65722

[0006] However, because the silica particles synthesized by these methods have a non-porous structure, the uniformity between the resin and silica particles is not sufficient. With conventional reactive silica, there was a trade-off where increasing the packing density to raise the elastic modulus also increased the dielectric constant. In large and complex package substrates such as 3D packages, it is sometimes necessary to achieve both high elastic modulus and low dielectric constant, but this has been difficult to achieve with conventional materials.

[0007] The inventors, through diligent research, aimed to improve the homogeneity of cured products such as package substrates and encapsulants by improving inorganic fillers. As a result, they discovered that by using a thermosetting resin composition containing a thermosetting resin and a two-phase continuous silica structure, compounding of the resin and silica structure is easy, improving the homogeneity of the cured product is expected, without impairing the dielectric properties of the thermosetting resin, and resulting in a cured product with a high elastic modulus and low thermal expansion coefficient compared to conventional non-porous silica particles, thus completing the present invention.

[0008] In other words, the present invention encompasses the following embodiments: [1] A thermosetting resin composition characterized by containing a thermosetting resin (A) and a two-phase continuous silica structure (B) consisting of a silica-based phase and an air phase. [2] The thermosetting resin composition according to [1], wherein at least a portion of the air phase of the two-phase continuous silica structure (B) is filled with the thermosetting resin (A). [3] The thermosetting resin composition according to [1] or [2], wherein the diameter of the air phase in the two-phase continuous silica structure (B) is in the range of 10 to 1000 nm. [4] The specific surface area of ​​the two-phase continuous silica structure (B) is 0.1 to 200 m². ２ A thermosetting resin composition according to any one of the above [1] to [3], in the range of / g. [5] The average particle size of the two-phase continuous silica structure (B) is 0.5 μm or more and less than 10 μm, and the skeleton volume is 1 μm ３ The skeletal surface area per unit area is 11.0 μm². ２ A thermosetting resin composition according to any of the above [1] to [4]. [6] The average particle size of the two-phase continuous silica structure (B) is 10 μm or more and 100 μm or less, and the skeleton volume is 1 μm ３ The skeletal surface area per unit area is 7.0 μm². ２The thermosetting resin composition according to any one of the above [1] to [4], which is as defined above. [7] The thermosetting resin composition according to any one of the above [1] to [6], wherein said two-phase co-continuous silica structure (B) is substantially spherical. [8] The thermosetting resin composition according to any one of the above [1] to [7], wherein the silica-based main phase in said two-phase co-continuous silica structure (B) is amorphous, and forms a three-dimensional network with nanowires having a thickness in the range of 5 to 1000 nm as a basic structure. [9] The thermosetting resin composition according to any one of the above [1] to [8], wherein said two-phase co-continuous silica structure (B) is surface-treated with a silane coupling agent.

[10] The thermosetting resin composition according to the above [9], wherein said silane coupling agent is aminosilane, methacrylsilane, vinylsilane or epoxysilane.

[11] The thermosetting resin composition according to any one of the above [1] to

[10] , wherein said thermosetting resin (A) comprises an epoxy resin or a maleimide resin.

[12] The thermosetting resin composition according to any one of the above [1] to

[10] , wherein said thermosetting resin (A) comprises a modified polyphenylene ether resin.

[13] The thermosetting resin composition according to any one of the above [1] to

[12] , wherein the mass ratio (A) / (B) of said thermosetting resin (A) to said two-phase co-continuous silica structure (B) is 10 / 90 to 90 / 10.

[14] A cured product of the thermosetting resin composition according to any one of the above [1] to

[13] .

[15] A semiconductor sealing material, a semiconductor device, a prepreg, a circuit board, a build-up film, and a build-up substrate, which use the thermosetting resin composition according to any one of the above [1] to

[13] .

[16] A two-phase co-continuous silica structure, which consists of a silica-based main phase and an air phase, has an average particle diameter of 0.5 μm or more and less than 10 μm, and has a skeleton surface area per 1 μm ３ of skeleton volume of 11.0 μm ２ or more.

[17] A two-phase co-continuous silica structure, which consists of a silica-based main phase and an air phase, has an average particle diameter of 10 μm or more and 100 μm or less, and has a skeleton surface area per 1 μm ３ of skeleton volume of 7.0 μm ２The above-mentioned two-phase continuous silica structure.

[18] The two-phase continuous silica structure according to

[16] or

[17] , wherein the diameter of the air phase in the two-phase continuous silica structure is in the range of 10 to 200 nm.

[19] The specific surface area of ​​the two-phase continuous silica structure is 7 to 100 m². ２ A two-phase continuous silica structure according to any of

[16] to

[18] , in the range of / g.

[20] A two-phase continuous silica structure according to any of

[15] to

[19] , wherein the two-phase continuous silica structure is surface-treated with a silane coupling agent.

[0009] The present invention provides a thermosetting resin composition and its cured product that do not impair the dielectric properties of the thermosetting resin and exhibit a higher elastic modulus and lower thermal expansion coefficient in the resulting cured product compared to conventional non-porous silica particles.

[0010] Figure 1 is an SEM image of the cross-section of the cured resin composition obtained in Example 3. Figure 2 is an SEM image of the cross-section of the cured resin composition obtained in Example 4. Figure 3 is an SEM image of the cross-section of the cured resin composition obtained in Comparative Example 1. Figure 4 is an SEM image of the cross-section of the cured resin composition obtained in Comparative Example 2. Figure 5 is an SEM image of the cross-section of the structure (B3) obtained in Example 9. Figure 6 is an SEM image of the cross-section of the structure (B4) obtained in Example 10. Figure 7 is an SEM image of the cross-section of the structure (B5) obtained in Example 11. Figure 8 is an SEM image of the cross-section of the structure (B6) obtained in Example 12. Figure 9 is an SEM image of the cross-section of the structure (B7) obtained in Example 13. Figure 10 shows the slice cross-section observation by PFIB-SEM and the results of the three-dimensional structural analysis constructed by AVIZO 3D of the structure (B3) obtained in Example 9. a represents the synthesis of silica skeleton and voids, b represents the silica skeleton, and c represents voids. Figure 11 shows the results of a PFIB-SEM slice cross-section observation and a 3D structural analysis constructed using AVIZO 3D for the structure (B4) obtained in Example 10. a represents the synthesis of the silica framework and voids, b represents the silica framework, and c represents the voids. Figure 12 shows the results of a PFIB-SEM slice cross-section observation and a 3D structural analysis constructed using AVIZO 3D for the structure (B5) obtained in Example 11. a represents the synthesis of the silica framework and voids, b represents the silica framework, and c represents the voids. Figure 13 shows the results of a PFIB-SEM slice cross-section observation and a 3D structural analysis constructed using AVIZO 3D for the structure (B6) obtained in Example 12. a represents the synthesis of the silica framework and voids, b represents the silica framework, and c represents the voids. Figure 14 shows the results of a PFIB-SEM slice cross-section observation and a 3D structural analysis constructed using AVIZO 3D for the structure (B7) obtained in Example 13. a represents the synthesis of a silica skeleton and voids, b represents the silica skeleton, and c represents the voids.

[0011] Next, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes, improvements, etc., can be made based on the ordinary knowledge of those skilled in the art, without departing from the spirit of the invention.

[0012] The thermosetting resin composition of the present invention is characterized by containing a two-phase continuous silica structure (B) consisting of a silica-based phase and an air phase. By using a silica structure having such a structure, the resin and the silica structure, which is the filler, are homogenized, and in particular, a portion of the resin is filled into the air layer in the silica structure, which effectively prevents the formation of minute spaces at the interface between the resin and the filler. As a result, it is expected that a cured product will be obtained that exhibits low thermal expansion coefficient and high elastic modulus without impairing the inherent dielectric properties of the resin.

[0013] <Thermosetting Resin (A)> The thermosetting resin (A) that can be used in the present invention is not particularly limited, and any of those that have been conventionally used in combination with inorganic fillers such as silica particles for various applications, especially in electrical materials, can be used. In particular, from the viewpoint of being able to exhibit low thermal expansion, the present invention includes epoxy resins, phenolic resins, maleimide resins, cyanate resins, melamine resins, urea resins, silicone resins, thermosetting polyimide resins, modified polyphenylene ether resins, thermosetting acrylic resins, etc., which are suitably used in semiconductor encapsulating materials, semiconductor devices, prepregs, circuit boards, flexible wiring boards, build-up films, multilayer printed wiring boards, or build-up substrates. In particular, from the viewpoint of more easily exhibiting the effects of the present invention and industrial availability, it is preferable to use epoxy resins, maleimide resins, cyanate resins, thermosetting polyimide resins, or silicone resins, and it is especially preferable to use epoxy resins, maleimide resins, or modified polyphenylene ether resins.

[0014] The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule, and examples thereof include bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol novolak-type epoxy resins, phenol novolak-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol novolak-type epoxy resins, phenol aralkyl-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane-type epoxy resins, cyclohexane dimethanol-type epoxy resins, naphthylene ether-type epoxy resins, trimethylol-type epoxy resins, and tetraphenylethane-type epoxy resins. The epoxy resins may be used alone, or two or more kinds thereof may be used in combination.

[0015] Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). When an epoxy resin is used as the thermosetting resin used in the present invention, the composition may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin.

[0016] Examples of liquid epoxy resins include glycirol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AF-type epoxy resins, naphthalene-type epoxy resins, glycidyl ester-type epoxy resins, glycidylamine-type epoxy resins, phenol novolac-type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol-type epoxy resins, cyclic aliphatic glycidyl ethers, and epoxy resins having a butadiene structure.

[0017] As specific examples of the liquid epoxy resin, there may be mentioned "EX-992L" manufactured by Nagase ChemteX Corporation, "YX7400" manufactured by Mitsubishi Chemical Corporation, "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "828US", "828EL", "825", and "Epicoat 828EL" (bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630", "630LSD", and "604" (glycidylamine-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycylol-type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L" and "EP-3980S" (glycidylamine-type epoxy resin) manufactured by ADEKA Corporation; "EP-4088S" (dicyclopentadiene-type epoxy resin) manufactured by ADEKA Corporation; "ZX1059" (mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "EX-991L" (epoxy resin containing alkyleneoxy skeleton and butadiene skeleton) manufactured by Nagase ChemteX Corporation; "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation; "PB-3600" manufactured by Daicel Corporation, "JP-100", "JP-200", and "JP-400" (epoxy resin having a butadiene structure) manufactured by Nippon Soda Co., Ltd.; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EG-280" (fluorene structure-containing epoxy resin) manufactured by Osaka Gas Chemicals Co., Ltd.; "EX-201" (cycloaliphatic glycidyl ether) manufactured by Nagase ChemteX Corporation; and the like.

[0018] Examples of solid epoxy resins include bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, naphthol novolac-type epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, phenol aralkyl-type epoxy resin, tetraphenylethane-type epoxy resin, and phenolphthaleimidine-type epoxy resin.

[0019] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol novolac-type epoxy resin); DIC's "N-695" (cresol novolac-type epoxy resin); DIC's "HP-7200", "HP-7200HH", "HP-7200H", and "HP-7200L" (dicyclopentadiene-type epoxy resins); DIC's "EXA-7311" and "EXA -7311-G3, EXA-7311-G4, EXA-7311-G4S, HP6000, HP6000L (naphthylene ether type epoxy resin); Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl aralkyl type epoxy resin); Nippon Steel Chemical & Material Co., Ltd.'s "ESN475V "ESN4100V" (naphthalene-type epoxy resin); "ESN485" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN375" (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YX4000HK", "YL7890" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; Examples include "YX7700" (phenol aralkyl type epoxy resin); "PG-100" and "CG-500" from Osaka Gas Chemical Co., Ltd.; "YX7760" (bisphenol AF type epoxy resin) from Mitsubishi Chemical Corporation; "YL7800" (fluorene type epoxy resin) from Mitsubishi Chemical Corporation; "jER1010" (bisphenol A type epoxy resin) from Mitsubishi Chemical Corporation; "jER1031S" (tetraphenylethane type epoxy resin) from Mitsubishi Chemical Corporation; and "WHR991S" (phenolphthalein type epoxy resin) from Nippon Kayaku Co., Ltd.These can be used individually or in combination of two or more types.

[0020] The epoxy equivalent of the epoxy resin can be appropriately selected depending on the application, but from the viewpoint of ease of handling, it is usually in the range of 50 g / eq. to 5,000 g / eq., preferably 130 g / eq. to 2,000 g / eq., and more preferably in the range of 150 g / eq. to 500 g / eq. The epoxy equivalent can be measured according to JIS K7236. Furthermore, the total chlorine content in the epoxy resin is preferably 0.001 to 20% by mass, more preferably 0.001 to 15% by mass, even more preferably 0.01 to 10% by mass, and still more preferably 0.01 to 5% by mass.

[0021] Examples of the phenolic resins include resol-type phenolic resins; phenol novolac resins, cresol novolac resins, and other novolac resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, α-naphthol, β-naphthol, and dihydroxynaphthalene with formaldehyde or ketones under an acidic catalyst; phenol aralkyl resins having a phenylene skeleton synthesized from the above-mentioned phenols and dimethoxyp-xylene or bis(methoxymethyl)biphenyl; phenol aralkyl resins such as phenol aralkyl resins having a biphenylene skeleton; and phenolic resins having a trisphenylmethane skeleton. Naphthols can also be used in the same manner as phenols. These can be used individually or in combination of two or more types.

[0022] The resol-type phenolic resin can be obtained, for example, by reacting phenols and aldehydes in the presence of a basic catalyst, usually with a molar ratio of aldehydes to phenols (aldehydes / phenols) of 1.3 to 1.7. Examples of phenols include one or more phenolic compounds selected from the group consisting of phenol, o-cresol, m-cresol, p-cresol, xylenol, alkylphenols, catechol, and resorcinol. Examples of aldehydes include aldehyde compounds such as formaldehyde, paraformaldehyde, and benzaldehyde, as well as substances that are sources of these aldehyde compounds, or solutions of these aldehyde compounds.

[0023] The novolac resin may be any modified novolac resin having structural units of benzene or substituted benzene oil interposed in its structure, or a phenolic resin containing a triazine skeleton that contains nitrogen atoms.

[0024] Furthermore, these phenolic resins may be combined with the epoxy resins and used as a curing agent.

[0025] Examples of commercially available phenolic resins (including naphthol resins) include "MEH-7700," "MEH-7810," and "MEH-7851" from Meiwa Kasei Co., Ltd., "NHN," "CBN," and "GPH" from Nippon Kayaku Co., Ltd., "SN170," "SN180," "SN190," "SN475," "SN485," "SN495," "SN-495V," "SN375," and "SN395" from Nippon Steel Chemical & Material Co., Ltd., and "TD-2090," "LA-7052," "LA-7054," "LA-1356," "LA-3018-50P," and "EXB-9500" from DIC Corporation.

[0026] Examples of the maleimide resins include aromatic maleimide compounds having an N-substituted maleimide group directly bonded to an aromatic ring, and aliphatic maleimide compounds having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon group. These may be used individually or in combination of two or more. Among these, aromatic maleimide compounds are preferred from the viewpoint of heat resistance and ease of handling, and aromatic bismaleimide compounds are more preferred.

[0027] Examples of aromatic maleimide compounds include bis(4-maleimidophenyl)methane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, biphenyl aralkyl maleimide resins, and aromatic bismaleimide resins having an indan skeleton. These can be appropriately selected depending on the application and required properties, but for example, when low dielectric properties are required, aromatic bismaleimide resins having an indan skeleton are preferred.

[0028] As the cyanate resin, for example, aromatic cyanate resins are preferred, specifically bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol S type cyanate ester resin, bisphenol sulfide type cyanate ester resin, phenylene ether type cyanate ester resin, naphthylene ether type cyanate ester resin, biphenyl type cyanate ester resin, tetramethylbiphenyl type cyanate ester resin, polyhydroxynaphthalene type cyanate ester resin, phenol novolac type cyanate ester resin, Examples include cresol novolac type cyanate ester resins, triphenylmethane type cyanate ester resins, tetraphenylethane type cyanate ester resins, dicyclopentadiene-phenol addition reaction type cyanate ester resins, phenol aralkyl type cyanate ester resins, naphthol novolac type cyanate ester resins, naphthol aralkyl type cyanate ester resins, naphthol-phenol co-condensed novolac type cyanate ester resins, naphthol-cresol co-condensed novolac type cyanate ester resins, biphenyl-modified novolac type cyanate ester resins, anthracene type cyanate ester resins, and the like. These may be used individually or in combination of two or more types.

[0029] Furthermore, the cyanate resin may be a modified one, for example, a butadiene-modified cyanate obtained by modifying butadiene. The details of the butadiene-modified cyanate may be obtained by mixing a cyanate ester compound and polybutadiene and then thermal polymerization, and / or by mixing a polymer of a cyanate ester compound and polybutadiene and then thermal polymerization. Alternatively, for example, a naphthol aralkyl type cyanate resin may be obtained by condensing a naphthol aralkyl type phenol resin obtained by reacting naphthols such as α-naphthol or β-naphthol with p-xylylene glycol, α,α'-dimethoxy-p-xylene, 1,4-di(2-hydroxy-2-propyl)benzene, etc., with a cyanide halogen.

[0030] Examples of the melamine resin include general-purpose melamine resins obtained by reacting melamine with formalin, and alkyl etherified melamine resins (e.g., butoxymethyl melamine resin, methoxymethyl melamine resin). Examples of the urea resin include general-purpose urea resins obtained by reacting urea with formaldehyde. In addition, melamine / urea resins obtained by co-condensation of melamine, urea, and formalin, and phenol / urea resins obtained by co-condensation of phenol, urea, and formalin can also be used as thermosetting resins.

[0031] The silicone resin may have siloxane bonds (Si-O-Si) and two or more curable reactive groups. Examples include resins with a methyl silicone main skeleton, resins with a methyl silicone main skeleton in which some of the methyl groups of the methyl silicone are replaced with phenyl groups, and resins in which some of the siloxane bonds are changed to alkyl chains or ethylene glycol chains. Examples of shapes include linear silicone, branched silicone, cyclic silicone, ladder-type silsesquioxane, random-type silsesquioxane, and cage-type silsesquioxane.

[0032] Methods for curing the silicone resin include a hydrosilylation reaction carried out in the presence of a hydrosilylation catalyst using a resin having hydrosilyl groups (-SiH) and carbon-carbon double bonds; a polycondensation reaction carried out in the presence of a condensation polymerization catalyst using a resin having alkoxy groups; a radical reaction of carbon-carbon double bonds using organic peroxides; and a method of curing by introducing reactive groups such as epoxy groups, amino groups, hydroxyl groups, and carboxyl groups into the resin skeleton. These can be used individually or in combination of two or more. From the viewpoint of curing time, heat resistance, and storage stability, the hydrosilylation reaction is preferred.

[0033] Furthermore, the silicone resin may also be one into which an organic compound has been introduced. For example, by introducing an organic compound into the resin skeleton using a hydrosilylation reaction, toughness and adhesiveness can be improved without impairing the inherent heat resistance and UV resistance of the silicone resin.

[0034] The thermosetting polyimide resin is a resin having imide bonds in its molecular main chain, and any known resin can be widely used, including those obtained by conventionally known methods or commercially available products. For example, it may be a resin produced from monoalkyl esters of 5-norbornene-2,3-dicarboxylic acid, aromatic diamines, aromatic tetracarboxylic acid dialkyl esters, or a highly heat-resistant polyimide resin produced from 1,3-bis(3-aminophenoxy)benzene, 3,3',4,4'-benzophenonetetracarboxylic acid dihydrate, 3-aminophenylacetylene, etc.

[0035] The modified polyphenylene ether resin mentioned above includes resins in which some of the functional groups of the monomers constituting the polyphenylene ether are replaced with one or more thermosetting functional groups such as amino groups, glycidyl groups, isocyanate groups, vinyl groups, carboxyl groups, epoxy groups, maleimide groups, and methacryloyl groups. As a result of the functional group substitution, this thermosetting modified polyphenylene ether resin exhibits thermosetting properties. When the functional groups of this resin are thermoset, the resin exhibits thermosetting properties by irreversibly forming a three-dimensional network structure while increasing its molecular weight.

[0036] The thermosetting acrylic resin may be any resin containing a copolymer of acrylic monomers that can undergo polymerization and curing reactions when heat (for example, 140°C or higher) is applied, and a crosslinking agent may be used depending on the structure of the selected resin. Alternatively, it may be a self-crosslinking acrylic resin obtained by copolymerizing monomer components such as N-hydroxyacrylamide, N-alkoxyacrylamide, N-alkylolacrylamide, and diacetoneacrylamide, or it may be a curing agent-combined acrylic resin that crosslinks by using a crosslinking agent such as melamine in combination with an acrylic monomer having substituents such as hydroxyl groups.

[0037] These thermosetting resins may be used individually, or multiple resins may be used in combination, as in the aforementioned combination of epoxy resin and phenolic resin.

[0038] <Two-phase continuous silica structure (B)> The two-phase continuous silica structure used in the present invention is not particularly limited as long as it consists of a phase mainly composed of silica and an air phase. For example, as provided in International Publication No. 2002 / 085785, an aqueous medium solution containing water glass as a silica source, a water-soluble polymer, and an acid can be prepared, and phase separation and gelation can be simultaneously caused from the solution to produce a wet gel. After washing the gel, it can be dried and then fired at a high temperature to reduce the hydrophilic silanol groups and produce a structure mainly composed of Q4 bonds. However, in the above method, it is difficult to adjust the particle size and the pore size of the air phase, and to control the particle shape. Therefore, it is preferable to react a specific amount of molybdenum compound with silica under specific temperature conditions.

[0039] Furthermore, the two-phase continuous silica structure obtained by the above manufacturing method may contain a small amount of molybdenum oxide that has not sublimated completely and remains on the silica surface. In addition, other manufacturing methods may also contain unavoidable components (other elements) depending on the raw materials and manufacturing method. From these perspectives, in this invention, "main component" means that 85% by mass or more of the solid portion forming the structure is silica, preferably 90% by mass or more, and more preferably 97% by mass or more is silica.

[0040] When the two-phase continuous silica structure (B) in the present invention is obtained by reacting a specific amount of molybdenum compound with silica under specific temperature conditions, the silica used as the precursor is not particularly limited as long as it is amorphous silica. For example, artificially synthesized silica-based materials such as silica gel, silica nanoparticles, mesoporous silica, or naturally occurring silica such as biosilica can be used.

[0041] The specific surface area of ​​the silica in the pre-structure is not particularly limited, but since the air phase can be easily formed as a continuum (through-hole), its specific surface area is 10 m². ２ It is preferable that it be 100m or more per gram. ２It is more preferable that the amount is greater than or equal to 1200 m². The upper limit of the specific surface area is not particularly limited, but 1200 m² is preferable. ２ / g or less, 900m ２ It may be less than / g.

[0042] The shape of the pre-structure silica is not particularly limited. Since the overall shape of micron size or larger can be maintained and a two-phase continuous silica structure can be formed, it is preferable to select a pre-structure silica of an appropriate shape depending on the purpose. For example, spherical, amorphous, aspect-defined structures (wires, fibers, ribbons, tubes, etc.), sheets, etc. can be suitably used.

[0043] The overall size of the silica prestructure is not particularly limited. For example, if silica particles of micron size or larger are used, a two-phase co-continuous silica structure can be formed while maintaining the size of a single particle. If silica particles with a small particle diameter are used, multiple particles can be fused together to form a large co-continuous silica structure.

[0044] Furthermore, the pre-structure silica may consist solely of silica, or it may be a composite of silica and an organic compound. For example, an organic / inorganic composite obtained by modifying silica with an organosilane, or a silica composite with adsorbed polymers, can be suitably used. When using these composites, there are no particular restrictions on the content of the organic compound, but from the viewpoint of efficiently producing a two-phase continuous silica structure, the content is preferably 60% by mass or less, and more preferably 30% by mass or less.

[0045] In the above-mentioned manufacturing method, a molybdenum compound is used from the viewpoint of suitably obtaining a silica structure composed of Q4 bonds. As for the molybdenum compound, even if it is molybdenum oxide, the molybdenum metal is an acidic anion (MO) formed by bonding with oxygen. ｘ ｎ－ ) may also be a compound containing ).

[0046] The molybdenum metal is an acidic anion (MO) formed by bonding with oxygen. ｘ ｎ－The compounds containing ) are not particularly limited as long as they can be converted to molybdenum oxide by high-temperature calcination. For example, molybdic acid, H ３ PMo １２ O ４０ , H ３ SiMo １２ O ４０ NH ４ Mo ７ O １２ These can be suitably used. Among these, when considering cost, it is preferable to use molybdenum oxide directly.

[0047] In the above-described method, a silica precursor is mixed with a molybdenum compound, and the mixture is calcined to substantially eliminate the silanol groups, thereby obtaining a two-phase continuous silica structure consisting of a phase mainly composed of silica with Q4 bonds and an air phase.

[0048] The charging ratio of the above mixture is preferably 30% by mass or less of the molybdenum compound relative to the precursor silica, more preferably in the range of 1 to 30% by mass, even more preferably in the range of 1.5 to 20% by mass, and still more preferably in the range of 3 to 20% by mass. When the amount of the molybdenum compound is within the above preferred range, the silica-based phase is more likely to become amorphous, and the formation of a continuous silica structure in both phases is efficiently facilitated.

[0049] Furthermore, there are no particular limitations on the process for preparing the mixture; for example, it may be a dry mixing method without using a solvent, or a wet mixing method using a solvent.

[0050] The above firing temperature can be any temperature at which molybdenum oxide sublimes, specifically, a range of 600 to 1100°C is preferred, a range of 700 to 1100°C is more preferred, and a range of 800 to 1000°C is even more preferred. When the firing temperature is within the above preferred range, the silica-based phase tends to become amorphous, making it easier to efficiently form a continuous silica structure with both phases.

[0051] When the charging ratio of the above mixture is 1 to 10% by mass of the molybdenum compound relative to the precursor silica, the calcination temperature is preferably in the range of 600 to 1100°C, more preferably in the range of 700 to 1100°C, and even more preferably in the range of 800 to 1000°C. When the charging ratio of the above mixture is more than 10% by mass to 30% by mass of the molybdenum compound relative to the precursor silica, the calcination temperature is preferably in the range of 600 to 900°C, more preferably in the range of 700 to 900°C, and even more preferably in the range of 800 to 900°C.

[0052] Regarding the atmosphere for the firing process described above, there are no particular limitations as long as oxygen is present, but an air atmosphere is preferable from the standpoint of safety and cost.

[0053] When a mixture of precursor silica and a molybdenum compound is calcined at a temperature of 600 to 1100°C, molybdenum oxide forms an adhesive film on the surface of the pores of the precursor silica. When silica with such an adhesive film is further calcined at a higher temperature, the molybdenum oxide sublimes, and the silanol groups in the silica substantially disappear, forming a two-phase co-continuous silica structure consisting of nano-sized voids that are continuous (penetrating) throughout the silica structure and a three-dimensional network skeleton of silica composed of Q4 bonds. In other words, it is thought that molybdenum oxide functions as a catalyst for the dehydration reaction of silanol groups during high-temperature calcination. At this time, by selecting the ratio of precursor silica and molybdenum compound used, the calcination temperature, or the pore properties of the precursor silica (pore size, distribution, etc.), the desired chemical properties and nanostructure of the two-phase co-continuous silica structure can be controlled.

[0054] In the present invention, the two-phase continuous silica structure (B) preferably has an amorphous silica-based phase. That is, the two-phase continuous silica structure (B) preferably contains substantially no crystalline silica. When the two-phase continuous silica structure (B) has an amorphous silica-based phase, the two-phase continuous silica structure (B) has low toxicity.

[0055] The two-phase continuous silica structure (B) preferably has a molybdenum content of 3.0% by mass or less relative to the total amount of the two-phase continuous silica structure. In the above-described manufacturing method, most of the molybdenum compound used sublimes through high-temperature firing treatment, forming a silica structure mainly composed of silica. However, a small amount of molybdenum compound that does not sublimate may be contained in the two-phase continuous silica structure. The content of these is usually 5% by mass or less, and in particular, with sufficient firing time and firing temperature, the content of these can be reduced to 3.0% by mass or less, and further reduced to 1% by mass or less. In addition, when used as a semiconductor encapsulant or the like, as described later, it is preferable not to include other metal elements, and it is preferable that the content of impurities other than unavoidable impurities be less than 0.5% by mass.

[0056] The diameter of the air phase in the two-phase continuous silica structure (B) used in the present invention may be in the range of 10 to 1000 nm, and is particularly preferably in the range of 50 to 1000 nm. When obtaining the two-phase continuous silica structure (B) by the above manufacturing method, the diameter of the cavity tunnels (air phase) in the two-phase continuous silica structure can be increased by raising the firing temperature, increasing the content of the molybdenum compound in the mixture, or using precursor silica having a high specific surface area and porosity. The diameter of the air phase being so-called macropores (50 nm or more) with virtually no micropores is preferable in that the thermosetting resin (A) can easily penetrate into the air phase, making compounding (formation of a continuous three-dimensional network of the thermosetting resin) easy, and consequently resulting in a lower thermal expansion coefficient and a higher elastic modulus of the cured product.

[0057] In the two-phase continuous silica structure (B) used in the present invention, the silica network preferably has nanowires as its basic structure, forming a three-dimensional network. The thickness of the nanowires is in the range of 5 to 1000 nm, and particularly preferably in the range of 30 to 500 nm. When obtaining the two-phase continuous silica structure (B) by the above manufacturing method, the thickness of the nanowire-like silica in the two-phase continuous silica structure can be increased by raising the firing temperature, increasing the content of the molybdenum compound in the mixture, or using a precursor silica with a high specific surface area. The diameter of the air phase or the thickness of the nanowires in the silica network of the two-phase continuous silica structure (B) was determined by measuring 200 points obtained from SEM observation images, as described in the examples.

[0058] The specific surface area of ​​the two-phase continuous silica structure (B) used in the present invention is 0.1 to 200 m². ２ Preferably in the range of / g, 0.1 to 100m ２ It is more preferable that the range is in the range of / g, and is between 0.1 and 50m ２ A range of / g is even more preferable.

[0059] The molybdenum compounds in the two-phase continuous silica structure obtained by the aforementioned manufacturing method form an amorphous structure on the outer surface and within the silica. These oxides can be removed by washing with an aqueous ammonia solution or an aqueous sodium hydroxide solution.

[0060] Molybdenum oxide functions as a dehydration catalyst at high temperatures, forming a two-phase continuous silica structure, but its bonding state is ２９ This can be confirmed by Si-CP / MAS NMR measurement. The three-dimensional silica network in the two-phase continuous silica structure obtained by the aforementioned manufacturing method differs from ordinary silica in that it consists of Q4 bonds and is similar to the silica in quartz glass.

[0061] Furthermore, in a high-concentration sodium hydroxide aqueous solution of 0.1 mol / L or higher, the silica wire surface in a two-phase co-continuum silica structure is etched, allowing the wire thickness, which is the basic structure of the silica network, to be reduced while maintaining the shape of the co-continuum.

[0062] The shape of the two-phase continuous silica structure (B) used in the present invention is not particularly limited, but it is preferably substantially spherical. Average particle diameter D ５０ The particles may be spherical particles of 0.5 to 500 μm, preferably 0.5 to 100 μm, and more preferably 1 to 60 μm. In this specification, the particle size D of the two-phase continuous silica structure (B) ５０ The average particle size of the two-phase continuous silica structure (B) was measured three times in an aqueous solvent at a stirring speed of 2500 rpm using a laser diffraction particle size analyzer (Spectris Co., Ltd., Mastersiszer 3000), and the average value was used to determine the average particle size D of the two-phase continuous silica structure (B). ５０ The calculation is performed as follows. When silica structure (B) is manufactured using the above method, the particle size can be easily adjusted, and the particle size distribution width can also be easily adjusted. In particular, when increasing the packing density, such as when used in semiconductor encapsulants, multiple particles with different particle sizes are used in combination, and from this viewpoint as well, silica structure (B) manufactured using the above method is suitable.

[0063] Furthermore, the two-phase continuous silica structure (B) used in the present invention consists of a phase mainly composed of silica and an air phase, has an average particle diameter of 0.5 μm or more and less than 10 μm, and a skeleton volume of 1 μm ３ The skeletal surface area per unit area is 11.0 μm². ２ Either the above, or the average particle diameter is 10 μm or more and 100 μm or less, and the skeleton volume is 1 μm. ３ The skeletal surface area per unit area is 7.0 μm². ２ It is especially preferable that the above conditions are met.

[0064] The aforementioned skeleton volume is 1 μm ３The method for measuring the skeletal surface area per particle involves selecting one of the plasma ions (N, O, Ar, Xe) from the cured material in the present invention described later, using a plasma focused ion beam scanning electron microscope (Helios 5 Hydra UX, manufactured by Thermo Fisher Scientific), processing it with an acceleration voltage of 30 kV to create a cross-section, repeatedly slicing it at equal intervals, and acquiring more than 300 SEM images per particle using the serial sectioning method with an acceleration voltage of 1 kV and a processing slice width of 10 to 30 nm for each slice cross-sectional observation image. A three-dimensional image is constructed from the SEM images acquired using AVIZO 3D (Ver. 2024.1, manufactured by Thermo Fisher Scientific), and the skeletal and void portions of the two-phase continuous silica structure (B) are extracted by binarization processing, and the volume, surface area, and porosity are quantified.

[0065] The measured values ​​obtained here are not affected by the type of thermosetting resin used or the curing conditions, are specific to the two-phase continuous silica structure (B) used, and are also independent of the type of plasma ions.

[0066] If the average particle size of the two-phase continuous silica structure (B) is 0.5 μm or more and less than 10 μm, the skeleton volume obtained above is 1 μm. ３ The skeletal surface area per unit area is 11.0 μm². ２ It is preferable that the value be above this, more preferably 12.0 or higher, and most preferably 14.0 or higher. The upper limit is not particularly limited, but when using the above-mentioned manufacturing method, values ​​of 30 or less can be suitably obtained.

[0067] Furthermore, if the average particle diameter of the two-phase continuous silica structure (B) is 10 μm or more and 10 μm or less, the skeleton volume obtained above is 1 μm. ３ The skeletal surface area per unit area is 7.0 μm². ２ It is preferable that the value be above this level, particularly preferably 7.5 or higher, and most preferably 8.0 or higher. The upper limit is not particularly limited, but when using the above-described manufacturing method, values ​​of 30 or less can be suitably obtained.

[0068] Relative to the average particle diameter, the skeleton volume is 1 μm. ３ By ensuring that the skeletal surface area per unit area is above a specific value, the pore shape in the two-phase continuous silica structure (B) is precisely controlled. As a result, the air phase in the structure (B) is sufficiently filled with the thermosetting resin (A), making it less likely for non-uniformity of the cured product to occur due to voids between the resin and filler, or discontinuities. Furthermore, both low thermal expansion and high modulus of elasticity of the cured product are achieved, effectively preventing warping and other issues that tend to occur when used in substrate applications. As a result, it can be suitably used in large substrates and substrate materials with complex structures.

[0069] The two-phase continuous silica structure (B) used in the present invention is preferably composed of Q4 bonds, as described above. In this case, aggregation is suppressed and homogeneous mixing can be achieved in the composition obtained by mixing it with the thermosetting resin (A). Furthermore, from the viewpoint of further suppressing discontinuity at the interface between the resin and the structure, the structure (B) can also be surface-treated with a silane coupling agent. The surface treatment may be performed by mixing the structure (B) and the silane coupling agent beforehand and then mixing them with the thermosetting resin (A), or it may be performed by mixing them all at once when preparing the composition.

[0070] Examples of the coupling agents mentioned above include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agents include methacrylicsilane, acrylicsilane, aminosilane, imidazolesilane, vinylsilane, and epoxysilane. Examples of the aminosilane include phenylaminosilane. The silane coupling agent is preferably aminosilane, methacrylicsilane, vinylsilane, or epoxysilane.

[0071] In the thermosetting resin composition of the present invention, the ratio of the thermosetting resin (A) to the two-phase continuous silica structure (B) can be appropriately set depending on the desired performance and application, but it is generally preferable that the mass ratio (A) / (B) is 10 / 90 to 90 / 10. In particular when used as a semiconductor encapsulant, in a composition that also includes other components described later, it is preferable that the mass ratio of the two-phase continuous silica structure (B) is in the range of 30 to 95% by mass, and more preferably in the range of 40 to 90% by mass. Furthermore, in order to achieve close packing, it is also a preferred embodiment to use a combination of multiple types of silica structures (B) with different particle sizes.

[0072] In the present invention, it is preferable that a portion of the thermosetting resin (A) is filled into the air phase of the two-phase continuous silica structure (B). For filling, there is no need to perform operations such as pressurizing or depressurizing; the resin can enter a portion of the air phase by the mixing method described later, potentially forming a composite. Because such a composite can be formed, the homogeneity of the resulting cured product is improved, and properties such as a low thermal expansion coefficient and high modulus of elasticity are favorably exhibited. From this viewpoint, it is preferable to use a thermosetting resin composition in which the resin component can enter the air phase of the silica structure (B), that is, a resin that is liquid at any point in the range from room temperature (25°C) to the curing temperature (for example, 180°C). This does not mean that the resin alone must be liquid; it is sufficient that the thermosetting resin composition containing an organic solvent or the like has fluidity. For example, even when using a thermosetting resin that is solid at room temperature, if the resin has fluidity during the heating process, it can enter and fill the air phase (pores) of the silica structure (B).

[0073] Furthermore, the thermosetting resin composition of the present invention may appropriately use various curing agents, curing accelerators, crosslinking agents, polymerization initiators, etc., that are used in combination with the aforementioned thermosetting resin. In addition, thermoplastic resins, rubber components, etc., may be added depending on the purpose.

[0074] For example, when using epoxy resins, phenolic resins, amine compounds, acid anhydrides, activated ester resins, etc., can be used as curing agents. These can be appropriately selected according to the required curability and properties of the cured product.

[0075] Examples of the amine curing agents include aliphatic amines such as diethylenetriamine (DTA), triethylenetetramine (TTA), tetraethylenepentamine (TEPA), diproprendiamine (DPDA), diethylaminopropylamine (DEAPA), N-aminoethylpiperazine, mensendiamine (MDA), isophoronediamine (IPDA), 1,3-bisaminomethylcyclohexane (1,3-BAC), piperidine, N,N,-dimethylpiperazine, and triethylenediamine; and aromatic amines such as m-xylenediamine (XDA), methanephenylenediamine (MPDA), diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), benzylmethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0076] Examples of the acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol trimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, and methylcyclohexendicarboxylic anhydride.

[0077] As the activated ester resin, a compound having one or more activated ester groups in one molecule can be used. Among these, compounds having one or more highly reactive ester groups in the molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred. The activated ester resin is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an activated ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an activated ester resin obtained from a carboxylic acid compound and / or a naphthol compound is more preferred.

[0078] Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0079] Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, and phenol novolac. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by the condensation of two phenol molecules with one dicyclopentadiene molecule.

[0080] Preferred examples of active ester resins include active ester resins containing a dicyclopentadiene-type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated phenol novolac, and active ester curing agents containing a benzoylated phenol novolac. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene-type diphenol structure are more preferred. The term "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0081] Commercially available activated ester resins include "HPC-8000", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65TM", "HPC-8000L-65MT" (manufactured by DIC Corporation), "DC808", "YLH1026", "DC808", "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation).

[0082] When using phenolic resin as a curing agent, among the phenolic resins described above, phenol novolac resin and cresol novolac resin are preferred. In addition, aromatic hydrocarbon formaldehyde resin-modified phenolic resin, dicyclopentadienephenol addition resin, phenol aralkyl resin (Zyloc resin), naphthol aralkyl resin, triphenylol methane resin, tetraphenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, and biphenyl-modified phenolic resin are preferred. Examples of polyvalent phenolic hydroxyl group-containing compounds include ol resins (polyvalent phenolic hydroxyl group-containing compounds in which the phenol nucleus is linked by a bismethylene group), biphenyl-modified naphthol resins (polyvalent naphthol compounds in which the phenol nucleus is linked by a bismethylene group), aminotriazine-modified phenol resins (polyvalent phenolic hydroxyl group-containing compounds in which the phenol nucleus is linked by melamine, benzoguanamine, etc.), and alkoxy-group-containing aromatic ring-modified novolac resins (polyvalent phenolic hydroxyl group-containing compounds in which the phenol nucleus and alkoxy-group-containing aromatic ring are linked by formaldehyde).

[0083] Furthermore, benzoxazine compounds and carbodiimide compounds can also be used as curing agents.

[0084] When using epoxy resin, the amount of curing agent used is not particularly limited, for example, in terms of the functional group equivalent ratio. However, from the standpoint of good mechanical properties of the resulting cured product, it is preferable that the amount of active groups in the curing agent is 0.5 to 1.5 equivalents, and more preferably 0.8 to 1.2 equivalents, for every 1 equivalent of epoxy groups in the epoxy resin.

[0085] The curing accelerator is not particularly limited, but examples include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, urea-based curing accelerators, etc. The curing accelerator may be used alone or in combination of two or more types.

[0086] Examples of the phosphorus-based curing accelerators include organic phosphine compounds such as triphenylphosphine, tributylphosphine, triparathylphosphine, diphenylcyclohexylphosphine, and tricyclohexylphosphine; organic phosphite compounds such as trimethylphosphine and triethylphosphine; and phosphonium salts such as ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, butylphosphonium tetraphenylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylphosphinetriphenylborane, tetraphenylphosphonium thiocyanate, tetraphenylphosphonium dicyanamide, butylphenylphosphonium dicyanamide, and tetrabutylphosphonium decanoate.

[0087] Examples of the amine-based curing accelerators include triethylamine, tributylamine, N,N-dimethyl-4-aminopyridine (4-dimethylaminopyridine, DMAP), 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo[5,4,0]-undecene-7 (DBU), and 1,5-diazabicyclo[4,3,0]-nonene-5 (DBN).

[0088] The imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole. Examples include ethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, and 2-methylimidazolin.

[0089] Examples of the guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]deca-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-butylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, and 1-phenylbiguanide.

[0090] Examples of the urea-based curing accelerator include 3-phenyl-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, chlorophenylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea.

[0091] Among the curing accelerators mentioned above, when used particularly in semiconductor encapsulation materials, it is preferable to use triphenylphosphine among phosphorus compounds and 1,8-diazabicyclo-[5,4,0]-undecene (DBU) among tertiary amines, due to their excellent curability, heat resistance, electrical properties, and moisture resistance reliability.

[0092] The amount of the curing accelerator used can be adjusted as appropriate to obtain the desired curing properties, but when combining epoxy resin and curing agent, for example, it is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the total amount of the two.

[0093] Examples of the crosslinking agent include epoxy compounds, cyanate compounds, maleimide compounds, allyl group-containing compounds, vinyl group-containing compounds, (meth)acryloyl group-containing compounds, metal chelate compounds, carbodiimide compounds, etc., and it is preferable to select the appropriate crosslinking agent depending on the thermosetting resin used.

[0094] Examples of polymerization initiators include peroxides such as benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, di-t-butyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilyltriphenylsilyl peroxide, and polymerization catalysts such as 2,3-dimethyl-2,3-diphenylbutane.

[0095] Examples of the thermoplastic resin include polyimide resin, phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, and the like. The thermoplastic resin may be used alone or in combination of two or more types.

[0096] Examples of the aforementioned rubber component include core-shell type rubber particles in which a part or all of the surface of a particulate core component, mainly composed of a crosslinked rubber-like polymer, is coated with a shell component by graft polymerization of a polymer different from the core component onto the surface of the particulate core component.

[0097] The thermosetting composition in this invention may be prepared without a solvent, or it may contain a solvent.

[0098] Specific examples of the aforementioned solvent are not particularly limited, but include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as diethyl ether and tetrahydrofuran; ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, mesitylene, 1,2,3-trimethylbenzene, and 1,2,4-trimethylbenzene; and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. These solvents may be used individually or in combination of two or more.

[0099] The amount of solvent used is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass, relative to the total mass of the curable composition. A solvent usage of 10% by mass or more is preferable due to its excellent handling properties. On the other hand, a solvent usage of 90% by mass or less is preferable from an economic standpoint.

[0100] The thermosetting composition of the present invention may optionally contain various additives such as flame retardants, inorganic fillers, mold release agents, pigments, colorants, and emulsifiers.

[0101] The aforementioned flame retardant is not particularly limited, but examples include inorganic phosphorus-based flame retardants, organophosphorus-based flame retardants, halogen-based flame retardants, etc. The flame retardant may be used alone or in combination of two or more types.

[0102] The inorganic phosphorus-based flame retardant is not particularly limited, but examples include red phosphorus; ammonium phosphate such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and polyammonium phosphate; and phosphate amides.

[0103] The organophosphorus flame retardants are not particularly limited, but include methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, dibutyl phosphate, monobutyl phosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, monoisodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, and stearyl acid phosphate. Phosphate esters such as isostearyl acid phosphate, oleyl acid phosphate, butyl pyrophosphate, tetracosyl acid phosphate, ethylene glycol acid phosphate, and (2-hydroxyethyl) methacrylate acid phosphate; diphenylphosphine such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and diphenylphosphine oxide; and 10-(2,5-dihydroxyphenyl)-10H-9-oxa Phosphorus-containing phenols such as -10-phosphaphenanthrene-10-oxide, 10-(1,4-dioxynaphthalene)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphenylhydroquinone, diphenylphosphenyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphenyl-1,4-phenyldiol, 1,5-cyclooctylenephosphenyl-1,4-phenyldiol; 9,10-dihydro-9-oxa-10-phos Examples include cyclic phosphorus compounds such as phaphenanthrene-10-oxide, 10-(2,5-dihydrooxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydrooxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; and compounds obtained by reacting the aforementioned phosphate esters, diphenylphosphine, or phosphorus-containing phenols with epoxy resins, aldehyde compounds, or phenolic compounds.

[0104] The halogenated flame retardant is not particularly limited, but examples include brominated polystyrene, bis(pentabromophenyl)ethane, tetrabromobisphenol A bis(dibromopropyl ether), 1,2-bis(tetrabromophthalimide), 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, and tetrabromophthalic acid.

[0105] The inorganic filler is not particularly limited, but known fillers other than the two-phase continuous silica structure (B) in the present invention may be used in combination as long as they do not impair the effects of the present invention. Examples include silica other than (B), alumina, glass, cordierite, barium sulfate, barium carbonate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium tungstate phosphate, zinc molybdate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, carbon black, etc. The inorganic filler may be used alone or in combination of two or more types.

[0106] Furthermore, in addition to the inorganic filler, an organic filler may be added, provided that it does not impair the properties of the present invention. Examples of the organic filler include polyamide particles.

[0107] In the present invention, the cured product is preferably obtained by curing the thermosetting resin composition described above. The thermosetting resin composition is obtained by uniformly mixing the above-mentioned components and can be easily cured in the same manner as conventionally known methods. Examples of the cured product include molded cured products such as laminates, cast products, adhesive layers, coatings, and films.

[0108] The aforementioned thermosetting reaction can be easily carried out without a catalyst depending on the combination of materials. However, if a faster reaction is desired, polymerization initiators such as the aforementioned organic peroxides and azo compounds, or basic catalysts such as phosphine compounds and tertiary amines may be added according to the formulation. The heating temperature during heat curing is not particularly limited, but is usually 100 to 300°C, and the heating time is 1 to 24 hours.

[0109] <Semiconductor Encapsulation Material> The thermosetting resin composition of the present invention can be used as a semiconductor encapsulation material. The thermosetting resin composition is suitable for this application because the cured product has a low coefficient of thermal expansion and a high modulus of elasticity.

[0110] Methods for obtaining the semiconductor encapsulating material include a method in which an additive, which is an optional component, is further melt-mixed with the thermosetting resin composition using an extruder, kneader, roll, etc., until it becomes uniform as needed.

[0111] <Semiconductor Device> The cured product of the semiconductor encapsulation material can be used as a semiconductor device containing it. A method for obtaining the semiconductor device is to mold the semiconductor encapsulation material using a casting mold, a transfer molding machine, an injection molding machine, etc., and then heat-cur it in a temperature range of room temperature (20°C) to 250°C.

[0112] <Prepreg> The thermosetting resin composition in the present invention can be used as a reinforcing substrate and as a prepreg, which is impregnated into the reinforcing substrate to form a semi-cured product. A method for obtaining a prepreg from the above thermosetting resin composition is to impregnate a reinforcing substrate (paper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth, glass mat, glass roving cloth, etc.) with a varnished thermosetting resin composition made by blending it with an organic solvent, and then heat it at a heating temperature corresponding to the type of solvent used, preferably 50 to 170°C. The mass ratio of the thermosetting resin composition to the reinforcing substrate used at this time is not particularly limited, but it is usually preferable to prepare it so that the resin content in the prepreg is 20 to 60% by mass.

[0113] Examples of the aforementioned organic solvents include methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, and propylene glycol monomethyl ether acetate. The selection and appropriate amount of these solvents can be appropriately chosen depending on the application. For example, when further manufacturing a printed circuit board from a prepreg as described below, it is preferable to use a polar solvent with a boiling point of 160°C or lower, such as methyl ethyl ketone, acetone, or dimethylformamide, and it is also preferable to use it in a proportion that results in a non-volatile content of 40 to 80% by mass.

[0114] <Circuit board> The prepreg can be laminated with copper foil to form a circuit board. A method for obtaining a printed circuit board from the thermosetting resin composition is to laminate the prepreg by a conventional method, add copper foil as appropriate, and heat-press it at 170 to 300°C for 10 minutes to 3 hours under pressure of 1 to 10 MPa.

[0115] <Build-up Film> The thermosetting resin composition in this invention can be used in build-up films. One method for manufacturing a build-up film is to apply the above-mentioned thermosetting resin composition onto a support film to form a thermosetting resin composition layer, thereby producing an adhesive film for multilayer printed circuit boards.

[0116] When manufacturing a build-up film from a thermosetting resin composition, it is essential that the film softens under the lamination temperature conditions of the vacuum lamination method (usually 70 to 140°C) and exhibits fluidity (resin flow) that allows for simultaneous lamination of the circuit board and resin filling of via holes or through holes present in the circuit board. It is preferable to formulate the above-mentioned components in such a way as to exhibit these characteristics.

[0117] Here, the diameter of the through-holes in a multilayer printed circuit board is typically 0.1 to 0.5 mm, and the depth is typically 0.1 to 1.2 mm. It is generally preferable to be able to fill the holes with resin within this range. When laminating both sides of the circuit board, it is desirable to fill about half of the through-holes.

[0118] The adhesive film described above can be manufactured by first preparing a varnish-like thermosetting resin composition, then applying this varnish-like composition to the surface of a support film, and finally drying the organic solvent by heating or blowing hot air to form a composition layer made of the thermosetting composition.

[0119] The thickness of the formed composition layer is usually preferably greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer of a circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm.

[0120] The composition layer may be protected by a protective film, as described later. Protecting it with a protective film prevents dirt and other debris from adhering to the surface of the resin composition layer and prevents scratches.

[0121] The support film and protective film mentioned above can be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate, polycarbonate, polyimide, and also release paper and metal foils such as copper foil and aluminum foil. In addition, the support film and protective film may be treated with a mat treatment, corona treatment, or release treatment.

[0122] The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and preferably in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0123] The support film described above is peeled off after lamination to the circuit board or after an insulating layer has been formed by heat curing. Peeling off the support film after heat curing the adhesive film prevents the adhesion of dust and other contaminants during the curing process. When peeling off after curing, the support film is usually treated with a release agent beforehand.

[0124] <Build-up Substrate> A build-up substrate can be obtained from the thermosetting resin composition of the present invention. A build-up substrate can be obtained by following the steps 1 to 3 below. In step 1, first, the thermosetting resin composition, which is appropriately blended with rubber, filler, etc., is applied to a circuit board on which a circuit has been formed using a spray coating method, a curtain coating method, etc., and then cured. In step 2, if necessary, holes such as predetermined through-holes are drilled in the circuit board on which the thermosetting resin composition has been applied, then it is treated with a roughening agent and the surface is washed with hot water to form irregularities on the substrate, and then a metal such as copper is plated. In step 3, the operations of steps 1 to 2 are repeated sequentially as desired to build up a resin insulating layer and a conductor layer of a predetermined circuit pattern alternately and form a build-up substrate. In the above steps, it is preferable to drill the through-holes after the formation of the outermost resin insulating layer. Furthermore, in the present invention, the build-up substrate can also be manufactured by forming a roughened surface by heating and pressing a resin-coated copper foil, which has been partially cured with the resin composition on a copper foil, onto a wiring board on which a circuit has been formed, at 170 to 300°C, thereby eliminating the plating process.

[0125] The cured product obtained from the thermosetting resin composition of the present invention has a low coefficient of thermal expansion and a high modulus of elasticity, making it suitable for use not only in semiconductor encapsulating materials, semiconductor devices, prepregs, circuit boards, and build-up films and build-up substrates, but also in a variety of other applications such as adhesives, resist materials, and matrix resins for fiber-reinforced resins, and is not limited to these applications.

[0126] The present invention will now be described in detail with reference to examples and comparative examples, but unless otherwise specified, "parts" and "%" refer to mass. The present invention is not limited thereto.

[0127] [Compositional analysis of nanostructures of two-phase co-continuous structures using X-ray fluorescence] Using a Primus IV X-ray fluorescence (XRF) analyzer (manufactured by Rigaku Corporation), approximately 70 mg of the prepared sample was placed on filter paper, covered with a PP film, and subjected to compositional analysis.

[0128] [Shape analysis of two-phase continuous silica structures using scanning electron microscopy] Samples prepared on double-sided carbon tape for SEM (manufactured by Nisshin EM Co., Ltd., 5 mm wide x 20 mm wide) were placed on the tape and measured using a scanning electron microscope (manufactured by JEOL Ltd., SEM-EDS JEOL7000) under an accelerating voltage of 15 kV.

[0129] [ ２９ [Evaluation of chemical bonding in two-phase co-continuous silica structures by Si CP / MAS NMR measurement] Using JEOL JNM-ECA600 ２９ Si CP / MAS NMR measurements were performed. For the chemical shift reference, polydimethylsilane was measured separately using the CP / MAS method, and the resulting peak was set to -33.8 ppm.

[0130] [Particle size D ５０ [Measurement] Using a laser diffraction particle size analyzer (Spectris Co., Ltd., Mastersiszer 3000), three measurements were taken in an aqueous solvent at a stirring speed of 2500 rpm, and the average value was obtained as the particle size distribution. The particle size at the point where the volume integrated % distribution curve intersects the horizontal axis at 50% was defined as D. ５０ That's what I decided.

[0131] [Specific Surface Area Measurement] Using a fully automatic specific surface area measuring device (Macsorb Model HM-1210, manufactured by Mountec Co., Ltd.), after pretreatment at 140°C / 30 minutes, the surface area per gram of sample, measured from the amount of nitrogen gas adsorbed by the BET flow method, is defined as the specific surface area (m²). ２ It was calculated as ( / g).

[0132] [Firing Method] Firing was carried out using a ceramic electric furnace SC-2045D-SP manufactured by Motoyama Co., Ltd.

[0133] Synthesis Example 1 [Synthesis of Silica Structure (B1)] As the silica precursor, 100 g of Sunsphere H-31 (manufactured by AGC SI-TECH) and 5 g of molybdenum oxide (manufactured by Nippon Muki Kagaku Co., Ltd.) were weighed into a bag and mixed by shaking by hand for 5 minutes. The resulting mixture was placed in a sac and heated in an electric furnace at a rate of 5°C / min to 1000°C, and then held at 1000°C for 5 hours to perform calcination. After cooling to room temperature at a rate of 5°C / min, it was removed from the sac to obtain a pale yellow powder. Subsequently, the obtained pale yellow powder was dispersed in 1000 g of ion-exchanged water, and the dispersion solution was stirred at room temperature for 2 hours. After passing it through a 106 μm sieve, the molybdenum remaining on the particle surface was removed by filtration and washing with water, and the mixture was dried at 120°C for 10 hours to obtain a white powder, a two-phase continuous silica structure (B1). As a result of measuring various physical properties using the method described above, the average particle diameter (D50 particle diameter) of the two-phase continuous silica structure (B1) was 2.9 μm, and the specific surface area was 7.4 m². ２ The result was [value] / g. Furthermore, SEM observation confirmed that the obtained silica structure was a two-phase continuous structure in which cavity tunnels permeated from the outer surface to the entire interior, and the silica and air phases were continuous with each other. The diameter of the air phase was 50–540 nm (average diameter 172 nm), the silica was amorphous, and the wire-like thickness was 60–310 nm (average diameter 143 nm), and the particles were spherical.

[0134] Synthesis Example 2 [Synthesis of Silica Structure (B2)] A two-phase continuous silica structure (B2) was synthesized in the same manner as in Synthesis Example 1, except that the precursor silica was replaced with Sunsphere H-121. The average particle size (D50 particle size) was 10.6 μm, and the specific surface area was 8.2 m². ２ The result was [value] / g. Furthermore, SEM observation confirmed that the obtained silica structure was a two-phase continuous structure in which cavity tunnels permeated from the outer surface to the entire interior, and the silica and air phases were continuous with each other. The diameter of the air phase was 30-550 nm (average diameter 174 nm), the silica was amorphous, and the wire-like thickness was 60-410 nm (average diameter 180 nm), and the particles were spherical.

[0135] Synthesis Example 3 [Synthesis of Maleimide Resin] Following Synthesis Example 1 of Japanese Patent Publication No. 6797356, an aromatic bismaleimide resin having an indan skeleton was synthesized. 48.5 g (0.4 mol) of 2,6-dimethylaniline, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were charged into a 1 L flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, and heated to 120°C while stirring. The temperature was further increased to 210°C while removing the distillate using a Dean-Stark tube, and the mixture was reacted for 3 hours. After that, it was cooled to 140°C, 145.4 g (1.2 mol) of 2,6-dimethylaniline was charged, and the temperature was increased to 220°C, and the mixture was reacted for 3 hours. After the reaction, the mixture was air-cooled to 100°C, diluted with 300 g of toluene, the activated clay was removed by filtration, and the solvent and unreacted materials were removed under reduced pressure to obtain the intermediate resin.

[0136] A thermometer, condenser, Dean-Stark trap, and stirrer were fitted into a 2 L flask, and 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were charged and stirred at room temperature. Next, a mixed solution of 364.1 g of the intermediate obtained above and 175 g of N,N-dimethylformamide (DMF) was added dropwise over 1 hour. After the addition was complete, the reaction was allowed to continue at room temperature for another 2 hours. 37.1 g of p-toluenesulfonic acid monohydrate was added, the reaction mixture was heated, and the azeotropic water and toluene were cooled and separated under reflux. Only the toluene was returned to the system, and the dehydration reaction was carried out for 8 hours. After air cooling to room temperature, the mixture was concentrated under reduced pressure, and the brown solution was dissolved in 600 g of ethyl acetate. The mixture was washed three times with 150 g of deionized water and three times with 150 g of 2% sodium bicarbonate aqueous solution. Sodium sulfate was added, the mixture was dried, and the reaction product was concentrated under reduced pressure. The resulting product was vacuum-dried at 80°C for 4 hours to obtain maleimide resin.

[0137] Example 1 [Preparation of Resin Substrate] 36 g of the two-phase continuous silica structure (B1) prepared in Synthesis Example 1, 54 g of the maleimide resin obtained in Synthesis Example 3, and 33 g of methyl ethyl ketone (hereinafter, MEK) were weighed and mixed in a disperser stirrer for 10 minutes until homogeneous. The resulting mixture was placed in a 200 mL round-bottom flask and the solvent was removed by distillation using an evaporator at 70°C for 1 hour. Subsequently, the resin composition was pulverized in a mortar and dried in a vacuum dryer at 120°C for 2 hours. The dried resin composition was heated using a vacuum press at 200°C for 2 hours, and then heat-cured at 250°C for 2 hours to produce a resin substrate containing maleimide resin and a two-phase continuous silica structure.

[0138] Example 2 A resin substrate was prepared in the same manner as in Example 1, except that the silica structure (B1) was changed to the two-phase continuous silica structure (B2) prepared in Synthesis Example 2.

[0139] Example 3 A resin substrate was prepared in the same manner as in Example 1, except that the silica structure (B1) was changed to 54 g, the maleimide resin to 43 g, and the MEK to 26.8 g.

[0140] Example 4 A resin substrate was prepared in the same manner as in Example 2, except that the silica structure (B2) was changed to 54 g, the maleimide resin to 43 g, and the MEK to 26.8 g.

[0141] Example 5 [Preparation of a resin substrate with epoxy resin and silica structure] 29.78 g of cresol novolac type epoxy resin EPICLON N-655-EXP (manufactured by DIC Corporation), 30.22 g of phenol resin MEHC-7851SS (manufactured by Meiwa Chemicals Co., Ltd.), 40 g of the silica structure (B1) prepared in Synthesis Example 1, and 1 g of epoxy silane KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and heated to 140°C to melt the resin and then stirred to uniformly disperse it. Subsequently, 0.6 g of triphenylphosphine (TPP) was added, and the mixture was heated and cured at 180°C for 10 minutes using a vacuum press to prepare a resin substrate containing epoxy resin and a two-phase continuous silica structure.

[0142] Example 6 A resin substrate was prepared in the same manner as in Example 5, except that the silica structure (B1) was changed to the two-phase continuous silica structure (B2) prepared in Synthesis Example 2.

[0143] Comparative Example 1 A resin substrate for Comparative Example 1 was prepared in the same manner as in Example 1, except that the silica particles were changed to SC2500-SXJ (manufactured by Admatex, 0.5 μm).

[0144] Comparative Example 2 A resin substrate for Comparative Example 2 was prepared in the same manner as in Example 1, except that the silica particles were changed to FB-105 (manufactured by Denka Co., Ltd., 12.2 μm).

[0145] Comparative Example 3 A resin substrate for Comparative Example 3 was prepared in the same manner as in Example 1, except that the silica particles were changed to SC2500-SXJ 54g.

[0146] Comparative Example 4: A resin substrate for Comparative Example 4 was prepared in the same manner as in Example 5, except that the silica particles were changed to FB-105.

[0147] Example 7 [Preparation of a resin substrate with modified PPE resin and silica structure] 80 g of methacryloyl-terminated polyphenylene ether (PPE) resin NORYL SA9000-111 (manufactured by SABIC Corporation), 20 g of triallyl isocyanurate TAIC (manufactured by Mitsubishi Chemical Corporation) as a crosslinking agent, 0.5 g of perbutyl P (manufactured by NOF Corporation), 68 g of the silica structure (B1) prepared in Synthesis Example 1, and 50 g of MEK were weighed and mixed in a disperser stirrer for 10 minutes until homogeneous. The obtained mixture was placed in a 500 mL round-bottom flask and the solvent was removed by distillation drying under reduced pressure at 70°C for 1 hour using an evaporator to obtain a resin composition. Subsequently, the resin composition was pulverized in a mortar and pestle, and a resin substrate containing modified PPE resin and a two-phase continuous silica structure was prepared by heating at 200°C for 2 hours using a vacuum press, followed by heat curing at 250°C for 2 hours.

[0148] Example 8 A resin substrate was prepared in the same manner as in Example 7, except that the silica structure (B1) was changed to the two-phase continuous silica structure (B2) prepared in Synthesis Example 2.

[0149] Comparative Example 5 A resin substrate for Comparative Example 5 was prepared in the same manner as in Example 7, except that the silica particles were changed to SC2500-SXJ (manufactured by Admatex, 0.5 μm).

[0150] The physical properties of the obtained resin substrate were measured using the following method.

[0151] The elastic modulus was measured by performing a bending test on the test specimens in accordance with JIS K6911:2006.

[0152] A resin substrate with a linear thermal expansion coefficient was prepared as a test piece approximately 5 mm square, and thermomechanical analysis was performed in compression mode using a thermomechanical analyzer (TMA: Seiko Instruments SS-6100). (Measurement load: 88.8 mN, heating rate: 3°C / min twice, measurement temperature range: room temperature to 250°C) The linear thermal expansion coefficient CTE in the glass region was measured during the second measurement.

[0153] Cross-sectional SEM observation of the resin substrate: The obtained resin substrate was subjected to osmium conductive treatment with an acceleration voltage of 3 kV and a film thickness of 2 nm using a PFIB-SEM (helios 5 Hydra UX, Thermo Fisher Scientific) to observe whether the resin was filling the silica structure. As shown in the figure, it was confirmed that the resin was filling even into the interior of the silica structure in the resin substrate obtained in the example.

[0154]

[0155]

[0156]

[0157]

[0158] [Three-dimensional structural analysis of two-phase continuous silica structure using PFIB-SEM] An epoxy resin and two-phase silica were mixed and cured. Using a plasma focused ion beam scanning electron microscope (Thermo Fisher Scientific Helios 5 Hydra UX), one of the plasma ions (N, O, Ar, Xe) was selected, and the material was processed with an acceleration voltage of 30 kV to create a cross-section. The slicing process was repeated at equal intervals, and for each slice cross-sectional image, a serial sectioning method was used to acquire more than 300 SEM images per particle with an acceleration voltage of 1 kV and a processed slice width of 10-30 nm. Three-dimensional images were constructed from SEM images acquired using AVIZO 3D (Ver. 2024.1, manufactured by Thermo Fisher Scientific). The skeleton and void portions of the two-phase continuous silica structure were extracted by binarization, and various parameters such as volume and surface area were quantified.

[0159] Example 9 [Synthesis of Silica Structure (B3)] 100 g of Sunsphere H-31 (manufactured by AGC SI-TECH) and 10 g of molybdenum oxide (manufactured by Nippon Muki Kagaku Co., Ltd.) were weighed into a bag and mixed by shaking by hand for 5 minutes. The resulting mixture was placed in a sac and heated in an electric furnace at a rate of 5°C / min to 700°C, and held at 700°C for 5 hours for firing. After cooling to room temperature at a rate of 5°C / min, it was removed from the sac to obtain a white powder. Subsequently, the obtained white powder was dispersed in 100 g of ion-exchanged water, the dispersion solution was stirred at room temperature for 2 hours, passed through a 106 μm sieve, and molybdenum remaining on the particle surface was removed by filtration and washing with water. The mixture was then dried at 120°C for 10 hours to obtain a two-phase continuous silica structure (B3) of white powder. Silica is amorphous, and the average particle size (D ５０ The particle size is 4.1 μm, and the specific surface area is 32.4 m². ２ The result was / g. Furthermore, SEM observation confirmed that the obtained silica structure had a two-phase continuous structure in which cavity tunnels penetrated from the outer surface to the entire interior, and the silica and air phases were continuous with each other.

[0160] Example 10 [Synthesis of Silica Structure (B4)] A two-phase continuous silica structure (B4) was synthesized in the same manner as in Example 9, except that the firing temperature was changed to 800°C. Silica is amorphous, and the average particle size (D ５０ Particle size: 5.0 μm, specific surface area: 9.8 m² ２ The result was / g. Furthermore, SEM observation confirmed that the obtained silica structure had a two-phase continuous structure in which cavity tunnels penetrated from the outer surface to the entire interior, and the silica and air phases were continuous with each other.

[0161] Example 11 [Synthesis of Silica Structure (B5)] A two-phase continuous silica structure (B5) was synthesized in the same manner as in Example 9, except that the amount of molybdenum oxide was changed to 20 g and the calcination temperature was changed to 800°C. Silica is amorphous, and the average particle size (D ５０ The particle size is 6.1 μm, and the specific surface area is 5.7 m². ２ The result was / g. Furthermore, SEM observation confirmed that the obtained silica structure had a two-phase continuous structure in which cavity tunnels penetrated from the outer surface to the entire interior, and the silica and air phases were continuous with each other.

[0162] Example 12 [Synthesis of Silica Structure (B6)] A two-phase continuous silica structure (B6) was synthesized in the same manner as in Example 9, except that the precursor silica was changed to Sunsphere H-121, the amount of molybdenum oxide was changed to 5 g, and the calcination temperature was changed to 800°C. The silica is amorphous, and the average particle size (D ５０ The particle size is 10.9 μm, and the specific surface area is 15.7 m². ２ The result was / g. Furthermore, SEM observation confirmed that the obtained silica structure had a two-phase continuous structure in which cavity tunnels penetrated from the outer surface to the entire interior, and the silica and air phases were continuous with each other.

[0163] Example 13 [Synthesis of Silica Structure (B7)] A two-phase continuous silica structure (B'2) was synthesized in the same manner as in Example 1, except that the precursor silica was changed to Sunsphere H-121, the amount of molybdenum oxide was changed to 10 g, and the calcination temperature was changed to 1000°C. The silica is amorphous, and the average particle size (D５０ The particle size is 13.2 μm, and the specific surface area is 3.5 m². ２ The result was / g. Furthermore, SEM observation confirmed that the obtained silica structure had a two-phase continuous structure in which cavity tunnels penetrated from the outer surface to the entire interior, and the silica and air phases were continuous with each other.

[0164] Table 1 summarizes the analysis results for the silica structures obtained in Examples 9 to 13.

[0165]

[0166] Example 14 [Preparation of Resin Substrate] 55 g of the two-phase continuous silica structure (B3) prepared in Example 9, 45 g of the maleimide resin obtained in Synthesis Example 3, and 27.5 g of methyl ethyl ketone (hereinafter, MEK) were weighed and mixed in a disperser stirrer for 10 minutes until homogeneous. The resulting mixture was placed in a 200 mL round-bottom flask and the solvent was removed by distillation using an evaporator at 70°C for 1 hour. Subsequently, the resin composition was pulverized in a mortar and dried in a vacuum dryer at 120°C for 2 hours. The dried resin composition was heated using a vacuum press at 200°C for 2 hours, and then heat-cured at 250°C for 2 hours to produce a resin substrate containing maleimide resin and a two-phase continuous silica structure.

[0167] Example 15 A resin substrate was fabricated in the same manner as in Example 14, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B4) fabricated in Example 10.

[0168] Example 16 A resin substrate was fabricated in the same manner as in Example 14, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B5) fabricated in Example 11.

[0169] Example 17 A resin substrate was fabricated in the same manner as in Example 5, except that the silica structure (B3) in Example 14 was changed to the two-phase continuous silica structure (B6) fabricated in Example 12.

[0170] Example 18 A resin substrate was fabricated in the same manner as in Example 5, except that the silica structure (B3) in Example 14 was changed to the two-phase continuous silica structure (B7) fabricated in Example 13.

[0171] Example 19 [Preparation of a resin substrate with epoxy resin and silica structure] 29.78 g of cresol novolac type epoxy resin EPICLON N-655-EXP (manufactured by DIC Corporation), 30.22 g of phenol resin MEHC-7851SS (manufactured by Meiwa Chemicals Co., Ltd.), 40 g of the silica structure (B3) prepared in Example 9, and 1 g of epoxy silane KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and heated to 140°C to melt the resin and then stirred to uniformly disperse it. Subsequently, 0.6 g of triphenylphosphine (TPP) was added, and the mixture was heated and cured at 180°C for 10 minutes using a vacuum press to prepare a resin substrate containing epoxy resin and a two-phase continuous silica structure.

[0172] Example 20 A resin substrate was fabricated in the same manner as in Example 19, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B4) fabricated in Example 10.

[0173] Example 21 A resin substrate was fabricated in the same manner as in Example 19, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B5) fabricated in Example 11.

[0174] Example 22 A resin substrate was fabricated in the same manner as in Example 19, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B6) fabricated in Example 12.

[0175] Example 23 A resin substrate was fabricated in the same manner as in Example 19, except that the silica structure (B3) was changed to the two-phase continuous silica structure (B7) fabricated in Example 13.

[0176]

[0177]

Claims

1. A thermosetting resin composition characterized by containing a thermosetting resin (A) and a two-phase continuous silica structure (B) consisting of a silica-based phase and an air phase.

2. The thermosetting resin composition according to claim 1, wherein at least a portion of the air phase of the two-phase continuous silica structure (B) is filled with the thermosetting resin (A).

3. The thermosetting resin composition according to claim 1, wherein the diameter of the air phase in the two-phase continuous silica structure (B) is in the range of 10 to 1000 nm.

4. The specific surface area of ​​the two-phase continuous silica structure (B) is 0.1 to 200 m². ２ The thermosetting resin composition according to claim 1, wherein the amount is in the range of / g.

5. The average particle size of the two-phase continuous silica structure (B) is 0.5 μm or more and less than 10 μm, and the skeleton volume is 1 μm. ３ The skeletal surface area per unit area is 11.0 μm². ２ The thermosetting resin composition according to claim 1, as described above.

6. The average particle diameter of the two-phase continuous silica structure (B) is 10 μm or more and 100 μm or less, and the skeleton volume is 1 μm. ３ The skeletal surface area per unit area is 7.0 μm². ２ The thermosetting resin composition according to claim 1, as described above.

7. The thermosetting resin composition according to claim 1, wherein the two-phase continuous silica structure (B) is substantially spherical.

8. The thermosetting resin composition according to claim 1, wherein the silica-based phase in the two-phase continuous silica structure (B) is amorphous and forms a three-dimensional network with nanowires having a thickness in the range of 5 to 1000 nm as the basic structure.

9. The thermosetting resin composition according to claim 1, wherein the two-phase continuous silica structure (B) is surface-treated with a silane coupling agent.

10. The thermosetting resin composition according to claim 9, wherein the silane coupling agent is aminosilane, methacrylicsilane, vinylsilane, or epoxysilane.

11. The thermosetting resin composition according to claim 1, wherein the thermosetting resin (A) comprises an epoxy resin or a maleimide resin.

12. The thermosetting resin composition according to claim 1, wherein the thermosetting resin (A) comprises a modified polyphenylene ether resin.

13. The thermosetting resin composition according to claim 1, wherein the mass ratio (A) / (B) of the thermosetting resin (A) to the two-phase continuous silica structure (B) is 10 / 90 to 90 / 10.

14. A cured product of a thermosetting resin composition according to any one of claims 1 to 13.

15. A semiconductor encapsulating material, semiconductor device, prepreg, circuit board, build-up film, and build-up substrate using the thermosetting resin composition according to any one of claims 1 to 13.

16. Consists of a silica-based phase and an air phase, with an average particle diameter of 0.5 μm or more and less than 10 μm, and a skeleton volume of 1 μm. ３ The skeletal surface area per unit area is 11.0 μm². ２ The above describes a two-phase, continuous silica structure.

17. A bicontinuous two-phase silica structure composed of a silica-based phase and an air phase, having an average particle diameter of 10 μm or more and 100 μm or less, and a skeleton surface area per 1 μm ３ of skeleton volume of 7.0 μm ２ or more.

18. The two-phase continuous silica structure according to claim 16 or 17, wherein the diameter of the air phase in the two-phase continuous silica structure is in the range of 10 to 200 nm.

19. The specific surface area of ​​the two-phase continuous silica structure is 7 to 100 m². ２ A two-phase continuous silica structure according to claim 16 or 17, wherein the range is / g.

20. The two-phase continuous silica structure according to claim 16 or 17, wherein the two-phase continuous silica structure is surface-treated with a silane coupling agent.

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