Resin composition film

Abstract

A resin composition film according to the present invention contains an epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), the resin composition film containing a total of 700-1400 mass parts of the aluminum nitride filler (B) and alumina filler (C) per 100 mass parts of the epoxy resin (A). The epoxy resin (A) contains a solid epoxy resin and a liquid epoxy resin. The amount of residual solvent is 3.5% or less. The minimum melt viscosity temperature determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60-180°C is in the 85-130°C range, the minimum melt viscosity η10% is in the 1,000-10,000 poise range, and the melt viscosity η0.1% at the minimum melt viscosity temperature, determined by dynamic viscoelasticity measurement at a strain of 0.1%, is in the 300,000-2,000,000 poise range.

Description

Resin composition film

[0001] The present invention relates to a resin composition film.

[0002] As electronic devices become more powerful and smaller, the wiring in multilayer printed wiring boards is becoming finer and denser. A known manufacturing technique for multilayer printed wiring boards is a build-up substrate manufacturing method using a semi-additive process, in which insulating layers and conductor layers are alternately stacked. The insulating layer can be efficiently formed by using a resin composition film for the insulating layer. A resin composition containing a thermosetting epoxy resin and silica is typically used for the resin composition film (Patent Document 1). The insulating layer is generally formed by overlaying the resin composition film on the conductor layer and thermally curing the resin composition film while adhering the conductor layer and the resin composition film together using a vacuum laminator or a heat press.

[0003] Therefore, the resin composition film is required to have high fluidity under lamination conditions so that it can follow the shape of the conductor layer, and it is common to use a combination of solid epoxy resin and liquid epoxy resin as the epoxy resin.

[0004] As a high-density mounting method, electronic component-embedded substrate technology, in which electronic components, previously mounted on the surface of a substrate, are embedded inside the substrate using an encapsulating resin, is also attracting attention. Cavities are formed in the core of a resin substrate or copper substrate, and electronic components such as ICs and capacitors are placed in the cavities. The cavities are then filled with a thermosetting resin, thereby encapsulating and embedding the electronic components. Resin composition films, such as those used in multilayer printed wiring boards, can also be used for this encapsulating resin. The resin composition film is placed on the core containing the electronic components, and the resin composition film is embedded in the cavities using a heat press, followed by thermal curing to achieve encapsulation. Even when a resin composition film is used in a component-embedded substrate, the resin composition film must have high fluidity to fill the cavities.

[0005] As a higher density mounting form, a module is also used in which a multilayer wiring layer is formed by the semi-additive method on the surface of a component-embedded substrate in which electronic components are embedded, and further electronic components are mounted on that surface.

[0006] Furthermore, in recent years, with the miniaturization and high performance of electronic devices, the density and packaging of semiconductor elements in multilayer printed wiring boards and component-embedded substrates have been increasing. Accordingly, the amount of heat generated by semiconductor elements has also increased, making it important to efficiently dissipate that heat from the substrate. Therefore, in order to address this issue, it has been proposed to use a high-thermal conductivity resin composition containing aluminum nitride, which has higher thermal conductivity than silica, as a resin composition film in the manufacture of multilayer printed wiring boards using the build-up method (Patent Document 2).

[0007] JP 2011-132507 A International Publication No. 2014 / 208352

[0008] Increasing the filling rate of the thermally conductive filler to improve the thermal conductivity of the cured product obtained from the resin composition film reduces the fluidity of the resin composition film and its embeddability. Increasing the amount of solvent remaining in the resin composition film to improve the fluidity of the resin composition film makes it more likely that voids will occur due to the evaporation of the remaining solvent when the resin composition film is embedded in a substrate or the like. Furthermore, increasing the amount of residual solvent increases the tackiness of the resin composition film, making it more likely to trap air when the resin composition film is attached to a substrate or the like, resulting in swelling. Therefore, an object of the present invention is to provide a highly thermally conductive resin composition film with good embeddability and attachability.

[0009] The present invention relates to, for example, the following items [1] to [8]. [1] An epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), wherein the total amount of the aluminum nitride filler (B) and the alumina filler (C) is 700 to 1,400 parts by mass per 100 parts by mass of the epoxy resin (A), the epoxy resin (A) comprises a solid epoxy resin (A-1) and a liquid epoxy resin (A-2), the amount of residual solvent is 3.5% or less, the minimum melt viscosity temperature determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60 to 180°C is in the range of 85 to 130°C, and the minimum melt viscosity η １０％ is in the range of 1,000 to 10,000 poise, and the melt viscosity η at the minimum melt viscosity temperature is determined by dynamic viscoelasticity measurement at a strain of 0.1%, a frequency of 1 Hz, and a temperature range of 60 to 180°C. ０．１％ A resin composition film having a viscosity in the range of 300,000 to 2,000,000 poise.

[0010] [2] The resin composition film according to [1], wherein the aluminum nitride filler (B) has an average particle size D50 of 0.2 to 3 μm and a maximum particle size Dmax of 5 μm or less, the alumina filler (C) has an average particle size D50 of 0.05 to 1.5 μm, and the average particle size D50 of the alumina filler (C) is smaller than the average particle size D50 of the aluminum nitride filler (B).

[0011] [3] The resin composition film according to [1] or [2], wherein the aluminum nitride filler (B) is a surface-treated aluminum nitride filler that has been surface-treated with a silane coupling agent (SC1) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, and the alumina filler (C) is a surface-treated alumina filler that has been surface-treated with a silane coupling agent (SC2) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, which is different from the organic reactive group possessed by the silane coupling agent (SC1).

[0012] [4] The resin composition film according to [3], wherein the silane coupling agent (SC1) has an organic reactive group containing an amino group of a secondary amine structure.

[0013] [5] The resin composition film according to [3] or [4], wherein the silane coupling agent (SC1) has an organic reactive group containing a phenylamino group.

[0014] [6] The resin composition film according to any one of [3] to [5], wherein the silane coupling agent (SC2) has an organic reactive group containing a (meth)acrylic group.

[0015] [7] A multilayer printed wiring board comprising the resin composition film according to any one of [1] to [6] or a cured product thereof.

[0016] [8] A component-embedded substrate comprising the resin composition film according to any one of [1] to [6] or a cured product thereof.

[0017] According to the present invention, it is possible to provide a resin composition film having high thermal conductivity and good embeddability and adhesion properties.

[0018] An example of an embodiment of the present invention will be described in detail below. However, the present invention is not limited to the embodiment described below, and can be implemented in any modified form without departing from the gist of the present invention.

[0019] [Resin Composition Film] The resin composition film of the present invention contains an epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), and the total amount of the aluminum nitride filler (B) and the alumina filler (C) is 700 to 1,400 parts by mass per 100 parts by mass of the epoxy resin (A). The epoxy resin (A) contains a solid epoxy resin (A-1) and a liquid epoxy resin (A-2). The amount of residual solvent in the resin composition film is 3.5% or less. The minimum melt viscosity temperature of the resin composition film, as determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60 to 180°C, is in the range of 85 to 130°C, and the minimum melt viscosity η １０％The melt viscosity η of the resin composition film at the minimum melt viscosity temperature is determined by dynamic viscoelasticity measurement at a strain of 0.1%, a frequency of 1 Hz, and a temperature range of 60 to 180°C. ０．１％ is in the range of 300,000 to 2,000,000 poise.

[0020] The amount of residual solvent in the resin composition film is 3.5% or less. The amount of residual solvent is preferably 2.0% or more, more preferably 2.4% or more, and preferably 3.3% or less, more preferably 3.2% or less. The amount of residual solvent is, for example, 2.0 to 3.3%. The amount of residual solvent is an index of the amount of solvent remaining in the resin composition film. The amount of residual solvent in the resin composition film can be measured by the method described in the Examples section.

[0021] When the amount of residual solvent is within the above range, the occurrence of voids due to the entrapment of volatile solvent is suppressed when the resin composition film is embedded in a substrate or the like, thereby resulting in excellent embeddability of the resin composition film. Furthermore, when the amount of residual solvent is within the above range, the tackiness of the resin composition film tends to be reduced, and when the resin composition film is adhered to a substrate or the like, the entrapment of air is suppressed, which makes it less likely for swelling to occur, resulting in excellent adhesion of the resin composition film. The amount of residual solvent in the resin composition film can be adjusted, for example, by adjusting the drying temperature, drying time, and air volume of the resin composition film during production.

[0022] The minimum melt viscosity η of the resin composition film determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60 to 180°C. １０％ The minimum melt viscosity η is 1,000 to 10,000 poise. １０％ is preferably 2,000 poise or more, more preferably 3,000 poise or more, and is preferably 8,000 poise or less, more preferably 7,000 poise or less. The minimum value of the complex viscosity determined by the dynamic viscoelasticity measurement with a strain of 10% is defined as the minimum melt viscosity η １０％ Let's say.

[0023] Minimum melt viscosity η １０％ represents the viscosity characteristics in a state where the strain is large, i.e., 10%, and is an index of the fluidity of the resin composition film. When the resin composition film is embedded in a substrate or the like, the resin composition film is significantly deformed at the embedded portion, so if the fluidity of the resin composition film is high, the resin composition film has excellent embeddability. Minimum melt viscosity η １０％ When the minimum melt viscosity η is within the above range, the resin composition film has high fluidity and excellent embeddability. １０％ can be within the above range.

[0024] The minimum melt viscosity temperature of the resin composition film determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60 to 180° C. is 85 to 130° C. The minimum melt viscosity temperature is preferably 95° C. or higher, more preferably 100° C. or higher, and preferably 125° C. or lower, more preferably 120° C. or lower. The complex viscosity determined by the dynamic viscoelasticity measurement at a strain of 10% is the minimum melt viscosity η １０％ The temperature at which this occurs is defined as the minimum melt viscosity temperature.

[0025] In the production of a multilayer printed wiring board or the like using the resin composition film, the heat pressing is usually carried out at an appropriate temperature selected within the range of 85 to 130° C. １０％ When the minimum melt viscosity temperature is within the above range, the temperature conditions for heat-pressure molding the resin composition film for use in multilayer printed wiring boards, component-embedded substrates, etc. can be set to a temperature around the minimum melt viscosity temperature, and therefore the resin composition film can be handled under conditions in which it has high fluidity.

[0026] The minimum melt viscosity temperature can be adjusted by changing the composition of the resin composition film, such as the amount of residual solvent, the filling rate, particle size and specific surface area of ​​the aluminum nitride filler (B) and the alumina filler (C), the type of silane coupling agent (SC1) and the silane coupling agent (SC2) described later, the type and viscosity of the epoxy resin (A), and the type and content of other components described later.

[0027] The melt viscosity η of the resin composition film is determined by dynamic viscoelasticity measurement at a strain of 0.1%, a frequency of 1 Hz, and a temperature range of 60 to 180°C. ０．１％ The melt viscosity η is 300,000 to 2,000,000 poise. ０．１％ is preferably 350,000 poise or more, more preferably 400,000 poise or more, and is preferably 1,500,000 poise or less, more preferably 1,000,000 poise or less. The complex viscosity value determined by the dynamic viscoelasticity measurement with a strain of 0.1% at the minimum melt viscosity temperature determined by the dynamic viscoelasticity measurement with a strain of 10% is defined as the melt viscosity η ０．１％ Let's say.

[0028] Melt viscosity η ０．１％ represents the viscosity characteristics when the deformation amount is very small, i.e., 0.1%, and is one of the indicators of the tackiness of a resin composition film. For example, when the resin composition film is attached to a substrate or the like at a temperature condition of about the minimum melt viscosity temperature, if the adhesiveness of the surface of the resin composition film is weak and the tackiness is low, entrapped air and the like will easily escape from the adhesive part, and swelling is unlikely to occur. Melt viscosity η ０．１％ When the melt viscosity η is in the above range, the tackiness of the resin composition film is low and the resin composition film has excellent adhesion. ０．１％ can be adjusted, for example, by changing the amount of remaining solvent, the filling rate, particle size and specific surface area of ​​the aluminum nitride filler (B) and the alumina filler (C), the type of the silane coupling agent (SC1) and the silane coupling agent (SC2) described later, and the composition of the resin composition film.

[0029] Minimum melt viscosity η １０％ Melt viscosity η ０．１％ The ratio (η ０．１％ / η １０％ ) is preferably 50 or more, more preferably 80 or more, even more preferably 100 or more, and is preferably 200 or less, more preferably 170 or less. When the ratio is within the above range, the resin composition film can achieve both fluidity and tackiness, and is excellent in embeddability and adhesion. The ratio is, for example, 50 to 170.

[0030] The minimum melt viscosity η of the resin composition film １０％ , minimum melt viscosity temperature and melt viscosity η ０．１％ can be measured using a viscoelasticity measuring device (rotational rheometer).

[0031] When the amount of residual solvent in the resin composition film is small, the generation of voids due to entrapment of volatile solvent when the resin composition film is embedded in a substrate or the like is suppressed. １０％ When the minimum melt viscosity η is low, the resin composition film has excellent flowability even if the amount of remaining solvent is small. １０％ When the amount of the remaining solvent is within the above range, voids are unlikely to occur when the resin composition film is embedded in a substrate or the like, and the resin composition film has excellent embeddability.

[0032] The amount of residual solvent in the resin composition film is small, and the melt viscosity η ０．１％ If the residual solvent amount and melt viscosity η are high, the tackiness of the resin composition film will be low. ０．１％ When the thickness is within the above range, air entrapment can be suppressed when the resin composition film is attached to a substrate or the like, and the resin composition film has excellent adhesiveness.

[0033] The thermal conductivity of the cured product obtained from the resin composition film is preferably 2.5 W / m·K or more, more preferably 2.8 W / m·K or more, and even more preferably 3.0 W / m·K or more. When the thermal conductivity of the cured product is high, the resin composition film can improve the heat dissipation properties of multilayer printed wiring boards and component-embedded substrates. The higher the thermal conductivity, the better, but it is generally 30 W / m·K or less. The thermal conductivity can be measured by a xenon flash method.

[0034] The thickness of the resin composition film is preferably 5 to 250 μm, more preferably 10 μm or more, even more preferably 15 μm or more, and more preferably 200 μm or less, even more preferably 180 μm or less.

[0035] <Epoxy Resin (A)> The resin composition film contains an epoxy resin (A). The epoxy resin (A) preferably contains a compound containing one or more epoxy groups in the molecule (hereinafter, also referred to as a "reactive epoxy resin"). The reactive epoxy resin may be a low molecular weight compound having an epoxy group. The reactive epoxy resin more preferably contains two or more epoxy groups in the molecule.

[0036] The epoxy resin (A) preferably contains a reactive epoxy resin in an amount of 50% by mass or more relative to the total amount of the epoxy resin (A). When the epoxy resin (A) contains a reactive epoxy resin, the resin composition film tends to soften and exhibit excellent fluidity. Therefore, when the resin composition film is used to manufacture a multilayer printed wiring board or a component-embedded substrate, the resin composition film easily conforms to the shape of the conductor layer of the multilayer printed wiring board, the cavity of the component-embedded substrate, and the electronic component. Furthermore, the resin composition film is converted into a desired shape and then heat-cured to produce a cured product with high strength and heat resistance, thereby improving the reliability of the substrate, etc. The upper limit of the content of the reactive epoxy resin in the total amount of the epoxy resin (A) is not particularly limited, and the entire epoxy resin (A) may be a reactive epoxy resin.

[0037] The epoxy resin (A) includes a solid epoxy resin (A-1) and a liquid epoxy resin (A-2). In this specification, an epoxy resin that is solid at a temperature of 25°C is referred to as a solid epoxy resin (A-1), and an epoxy resin that is liquid at 25°C is referred to as a liquid epoxy resin (A-2).

[0038] When the epoxy resin (A) contains a solid epoxy resin (A-1), the strength and heat resistance of the cured product obtained by heat-curing the resin composition film tend to be improved. On the other hand, since the fluidity of the solid epoxy resin (A-1) tends to be low, the fluidity of the resin composition film is improved by using a highly heat-resistant solid epoxy resin (A-1) in combination with a highly fluid liquid epoxy resin (A-2), and the fluidity of the resin composition film is improved, allowing the resin composition film to conform to the desired substrate shape.

[0039] The solid epoxy resin (A-1) is preferably a reactive epoxy resin. Examples of the solid epoxy resin (A-1) include tetrafunctional naphthalene epoxy resins, trifunctional naphthalene epoxy resins, trisphenolmethane epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, naphthol novolac epoxy resins, naphthol cresol novolac epoxy resins, dicyclopentadiene epoxy resins, biphenyl aralkyl epoxy resins, bixylenol epoxy resins, naphthylene ether epoxy resins, biphenyl epoxy resins, and fluorene epoxy resins, and more preferred are tetrafunctional naphthalene epoxy resins, biphenyl aralkyl epoxy resins, trisphenolmethane epoxy resins, bixylenol epoxy resins, naphthylene ether epoxy resins, and fluorene epoxy resins.

[0040] Examples of tetrafunctional naphthalene-type epoxy resins include "HP-4700" and "HP-4710" manufactured by DIC Corporation. Examples of cresol novolac-type epoxy resins include "N-690" and "N-695" manufactured by DIC Corporation. Examples of dicyclopentadiene-type epoxy resins include "HP-7200," "HP-7200L," and "HP-7200H" manufactured by DIC Corporation.

[0041] Examples of naphthylene ether type epoxy resins include "HP6000" and "HP-6000H" manufactured by DIC Corporation. Examples of trisphenolmethane type epoxy resins include "EPPN-501H," "EPPN-501HY," and "EPPN-502H" manufactured by Nippon Kayaku Co., Ltd. Examples of naphthol cresol novolac epoxy resins include "NC7000L," "NC-7000H," and "NC-7300L" manufactured by Nippon Kayaku Co., Ltd.

[0042] Examples of biphenylaralkyl epoxy resins include "NC-3000H," "NC-3000," "NC-3000L," "NC-3100," and "NC-3500" manufactured by Nippon Kayaku Co., Ltd. Examples of naphthol novolac epoxy resins include "ESN475" and "ESN485" manufactured by Nippon Steel Chemical Co., Ltd.

[0043] Examples of biphenyl-type epoxy resins include "YX4000H" and "YL6121" manufactured by Mitsubishi Chemical Corporation. Examples of bixylenol-type epoxy resins include "YX4000HK" manufactured by Mitsubishi Chemical Corporation. Examples of fluorene-type epoxy resins include "YL7800" manufactured by Mitsubishi Chemical Corporation.

[0044] From the viewpoint of formability of the resin composition film, the softening point of the solid epoxy resin (A-1) is preferably 40 to 130° C. The softening point is more preferably 45° C. or higher, even more preferably 50° C. or higher, and more preferably 110° C. or lower, even more preferably 100° C. or lower. The solid epoxy resin (A-1) may be used alone or in combination of two or more.

[0045] When producing the resin composition film, the solid epoxy resin (A-1) may be used as a composition containing the solid epoxy resin (A-1) and an organic solvent. The organic solvent in the composition may be any solvent capable of dissolving the solid epoxy resin (A-1). Examples include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, N,N-dimethylformamide, methyl isobutyl ketone, N-methylpyrrolidone, n-hexane, cyclohexane, cyclohexanone, and solvent naphtha, which is a mixture thereof. Methyl ethyl ketone is preferred. The boiling point of the organic solvent is preferably 200°C or lower, more preferably 180°C or lower, from the viewpoint of ease of removal of the organic solvent. The organic solvent may be used alone, or two or more types may be used.

[0046] The content of nonvolatile matter in the composition is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 70% by mass, from the viewpoint of the solubility of the solid epoxy resin (A-1) in the organic solvent. In this specification, the term "nonvolatile matter" refers to all components excluding the solvent. The content of the organic solvent in the composition is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, and even more preferably 30 to 60% by mass. The composition may contain components other than the epoxy resin (A), aluminum nitride filler (B), and alumina filler (C) that may be contained in the resin composition film.

[0047] When the epoxy resin (A) contains the liquid epoxy resin (A-2), the resin composition film tends to have excellent fluidity, and therefore, when the resin composition film is molded under heat and pressure for use in a multilayer printed wiring board or a component-embedded substrate, the resin composition film has excellent conformability to the shapes of a conductor layer and a cavity, and excellent embeddability.

[0048] The liquid epoxy resin (A-2) is preferably a reactive epoxy resin, and examples of the liquid epoxy resin (A-2) include bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, and naphthalene epoxy resin, and more preferably bisphenol A epoxy resin and bisphenol F epoxy resin.

[0049] Examples of bisphenol A epoxy resins include "jER828," "jER828EL," and "jER828US" manufactured by Mitsubishi Chemical Corporation. Examples of bisphenol F epoxy resins include "jER806," "jER806H," and "jER807" manufactured by Mitsubishi Chemical Corporation, and "YDF-8170C" manufactured by Nippon Steel Chemical & Material Co., Ltd. Examples of phenol novolac epoxy resins include "jER152" manufactured by Mitsubishi Chemical Corporation.

[0050] An example of a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin is "ZX1059" manufactured by Nippon Steel Chemical & Material Co., Ltd. An example of a naphthalene type epoxy resin is "HP4032", "HP4032D" and "HP4032SS" manufactured by DIC Corporation. The liquid epoxy resin (A-2) may be used alone or in combination of two or more types.

[0051] The viscosity of the liquid epoxy resin (A-2) at 25°C is preferably 500 poise or less, more preferably 5 to 300 poise. The viscosity is further preferably 10 poise or more, and even more preferably 200 poise or less. When the viscosity of the liquid epoxy resin (A-2) at 25°C is within the above range, the resin composition film tends to have excellent flowability and embeddability.

[0052] The mass ratio of the content of the solid epoxy resin (A-1) to the content of the liquid epoxy resin (A-2) (solid epoxy resin content: liquid epoxy resin content) is preferably in the range of 9:1 to 1:9, more preferably 4:1 to 1:4, even more preferably 3:1 to 1:3, and particularly preferably 2:1 to 1:2. By keeping this ratio within the above range, it is possible to achieve both high fluidity of the resin composition film and high heat resistance of the cured product.

[0053] The epoxy equivalent of the epoxy resin (A) is preferably 50 to 4500, more preferably 50 to 3000. The epoxy equivalent is further preferably 80 or more, particularly preferably 100 or more, and further preferably 2000 or less, particularly preferably 1000 or less. When the epoxy equivalent of the epoxy resin (A) is within the above range, the cured product obtained by curing the resin composition film tends to have excellent crosslink density, and the resin composition film tends to have sufficient heat resistance and mechanical strength. The epoxy equivalent can be measured according to JIS K7236. The epoxy equivalent is the mass of resin per equivalent of epoxy groups. The epoxy resin (A) may be one type or two or more types.

[0054] <Aluminum Nitride Filler (B)> The resin composition film contains an aluminum nitride filler (B). When the resin composition film contains the aluminum nitride filler (B), a cured product obtained from the resin composition film can have high thermal conductivity.

[0055] The average particle size D50 of the aluminum nitride filler (B) is preferably 0.2 to 3 μm. The average particle size D50 is more preferably 0.5 μm or more, and more preferably 1.5 μm or less. When the average particle size D50 of the aluminum nitride filler (B) is within the above range, the resin composition film can be easily molded to a thickness of several μm to several hundred μm. Furthermore, when the resin composition film is heated and pressurized for use in multilayer printed wiring boards and component-embedded boards, the resin composition film exhibits excellent conformability to the complex shapes of conductor layers and cavities and narrow gaps. Furthermore, cured products obtained from films with thicknesses within the above range tend to have high thermal conductivity. The average particle size D50 in the present invention is the particle size at the cumulative 50% value on a volume basis in the particle size distribution measured by laser diffraction scattering. The particle size distribution can be measured by the method described in the Examples section below.

[0056] The maximum particle size Dmax of the aluminum nitride filler (B) is preferably 5 μm or less, more preferably 4.5 μm or less, and even more preferably 4 μm or less. When the maximum particle size Dmax of the aluminum nitride filler (B) is within this range, the resin composition film tends to have excellent fluidity. Therefore, the resin composition film has excellent conformability to the shapes of the conductor layer and cavity. Furthermore, when the maximum particle size Dmax of the aluminum nitride filler (B) is within this range, the resin composition film can be easily formed to a thickness of several μm to several hundred μm, and a cured product obtained from a film having a thickness within this range tends to have high thermal conductivity.

[0057] The maximum particle size Dmax in the present invention is the maximum particle size measured in the particle size distribution measured by a laser diffraction scattering method (particle size at 100% cumulative volume). The particle size distribution can be measured by the method described in the Examples section below.

[0058] The specific surface area SA of the aluminum nitride filler (B) is preferably 0.5 to 10 m ２ The specific surface area SA is more preferably 0.8 m ２ / g or more, more preferably 1.0m ２ / g or more, more preferably 7m２ / g or less, more preferably 5m ２ / g or less. When the specific surface area SA of the aluminum nitride filler (B) is within the above range, the aluminum nitride filler (B) has excellent dispersibility in the epoxy resin (A), and the flowability of the resin composition film tends to be improved, and the embeddability also tends to be improved. The specific surface area SA in the present invention can be measured by the BET method using a flow-type automatic specific surface area measuring device. The specific surface area SA can be measured by the method described in the Examples section below.

[0059] The aluminum nitride filler (B) may be an aluminum nitride filler that has not been surface-treated with a surface treatment agent. An aluminum nitride filler that has not been surface-treated with a surface treatment agent is also called an "untreated aluminum nitride filler."

[0060] An example of a commercially available untreated aluminum nitride filler is aluminum nitride filler HF-01D (manufactured by Tokuyama Corporation). As the untreated aluminum nitride filler, commercially available aluminum nitride powder whose particle size distribution has been adjusted using a sieve, a classifier, or the like may be used. The method for producing the untreated aluminum nitride filler is not particularly limited, and aluminum nitride fillers produced by known methods can be used. Methods for producing the untreated aluminum nitride filler include, for example, direct nitridation, reduction nitridation, and vapor phase synthesis.

[0061] The aluminum nitride filler (B) is preferably an aluminum nitride filler that has been surface-treated with a surface treatment agent. An aluminum nitride filler that has been surface-treated with a surface treatment agent is also called a "surface-treated aluminum nitride filler." By performing the surface treatment with a surface treatment agent, the water resistance of the aluminum nitride filler is improved, and its affinity with the epoxy resin (A) is improved. Therefore, the filling ability of the aluminum nitride filler is improved, and the fluidity of the resin composition film can be improved.

[0062] Examples of the surface treatment agent include silane compounds such as silane coupling agents, aluminate coupling agents, and titanate coupling agents. The surface treatment agent is preferably a silane compound, from the viewpoint of increasing the reaction rate between the surface treatment agent and the aluminum nitride filler.

[0063] Examples of the silane compound used as the surface treatment agent include silane compounds having a reactive functional group and silane compounds having a non-reactive functional group. Examples of the silane compound having a reactive functional group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like. Silanes include alkoxysilanes such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropylmethyldimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, and allyltrimethoxysilane.

[0064] Examples of silane compounds having a non-reactive functional group include methyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trifluoropropyltrimethoxysilane, and trifluoropropylmethyldimethoxysilane.

[0065] In addition to the above-mentioned compounds, examples of silane compounds that can be used as the surface treatment agent include chlorosilanes such as vinyltrichlorosilane, methyltrichlorosilane, dimethyldichlorosilane, trichloromethylsilane, ethyldimethylchlorosilane, propyldimethylchlorosilane, phenyltrichlorosilane, trifluoropropyltrichlorosilane, and isopropyldiethylchlorosilane.

[0066] The surface treatment agent is preferably a silane coupling agent having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom among the silane compounds. That is, the aluminum nitride filler (B) is preferably a surface-treated aluminum nitride filler that has been surface-treated with a silane coupling agent (SC1) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom.

[0067] The silane coupling agent (SC1) is a silane compound having a hydrolyzable group and an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, and is preferably an alkoxysilane compound having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom.

[0068] The hydrolyzable group is directly bonded to the silicon atom. Examples of the hydrolyzable group include alkoxy groups such as methoxy and ethoxy groups. An organic reactive group containing an oxygen atom, nitrogen atom, or sulfur atom refers to a substituent other than a hydrolyzable group that contains a reactive functional group containing an oxygen atom, nitrogen atom, or sulfur atom and is bonded to a silicon atom. The reactive functional group containing an oxygen atom, nitrogen atom, or sulfur atom is preferably bonded to the silicon atom via a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms.

[0069] Examples of reactive functional groups containing an oxygen atom include a hydroxyl group, a carbonyl group, a (meth)acrylic group, and an ether group bonded to two carbon atoms (-C-O-C- bond). The ether group bonded to two carbon atoms may be a cyclic ether group.

[0070] Examples of reactive functional groups containing a nitrogen atom include -NR １ R ２ Examples of the R include an amino group, a cyano group, a pyrrolidinyl group, and an isocyanate group. １ and R ２ each independently represents a hydrogen atom, an alkyl group, or an aryl group. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and even more preferably 1 to 10 carbon atoms. The alkyl group may be linear, branched, or cyclic. The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and even more preferably 6 to 10 carbon atoms.

[0071] Examples of reactive functional groups containing sulfur atoms include mercapto groups, sulfide groups, sulfo groups, and sulfonyl groups. The silane coupling agent (SC1) may have only one organic reactive group, or may have two or more organic reactive groups. The organic reactive group may include, for example, a reactive functional group containing an oxygen atom and a reactive functional group containing a nitrogen atom.

[0072] Examples of the silane coupling agent (SC1) include 2-((3-(triethoxysilyl)propyl)carbamoyl)benzoic acid, triethoxysilylpropylmaleamic acid, 2-((3-(trimethoxysilyl)propyl)carbamoyl)benzoic acid, trimethoxysilylpropylmaleamic acid, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane amine, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropylmethyldimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-(methylamino)propyltrimethoxysilane.

[0073] From the viewpoint of embeddability and adhesion of the resin composition film, the silane coupling agent (SC1) preferably has an organic reactive group containing an oxygen atom or a nitrogen atom, more preferably has an organic reactive group containing an amino group of a secondary amine structure, a (meth)acrylic group or an epoxy group, even more preferably has an organic reactive group containing an amino group of a secondary amine structure, and particularly preferably has an organic reactive group containing a phenylamino group.

[0074] When the silane coupling agent (SC2) described below has an organic reactive group containing a (meth)acrylic group, the silane coupling agent (SC1) preferably does not have an organic reactive group containing a (meth)acrylic group.

[0075] The amount of the surface treatment agent used when surface treating the aluminum nitride filler with the surface treatment agent is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 4 parts by mass, per 100 parts by mass of the aluminum nitride filler before surface treatment.

[0076] The surface treatment method using the surface treatment agent can be a known method, and may be either a dry surface treatment or a wet surface treatment. Dry surface treatment is a method in which the aluminum nitride filler before surface treatment is mixed with the surface treatment agent without using a large amount of solvent. Examples of dry surface treatment include a method in which the surface treatment agent is gasified and mixed with the aluminum nitride filler before surface treatment, a method in which the liquid surface treatment agent is sprayed or dropped and mixed with the aluminum nitride filler before surface treatment, and a method in which the surface treatment agent is diluted with a small amount of organic solvent to increase the amount of liquid, and then sprayed or dropped.

[0077] Wet surface treatment is a method in which a solvent is used when mixing an aluminum nitride filler before surface treatment with the surface treatment agent. For example, an example of the wet surface treatment is a method in which an aluminum nitride filler before surface treatment, the surface treatment agent, and a solvent are mixed together, and then the solvent is removed by drying or the like.

[0078] Before being subjected to the surface treatment with the surface treatment agent, the aluminum nitride filler may be subjected to a water-resistant treatment for oxidizing the filler surface.

[0079] The aluminum nitride filler (B) may contain impurities such as alkaline earth elements and rare earth elements derived from raw materials or intentionally added during the synthesis process, with the upper limit being approximately 5 parts by mass per 100 parts by mass of the aluminum nitride filler (B). An amount of impurities that significantly reduces the crystallinity of aluminum nitride is undesirable because it causes a decrease in the thermal conductivity of the cured product obtained from the resin composition film. The aluminum nitride content in the aluminum nitride filler (B) is preferably 95% by mass or more, more preferably 99% by mass or more. The aluminum nitride filler (B) may be one type or two or more types.

[0080] <Alumina Filler (C)> The resin composition film contains an alumina filler (C). The average particle size D50 of the alumina filler (C) is preferably 0.05 to 1.5 μm. The average particle size D50 is more preferably 0.1 μm or more, even more preferably 0.15 μm or more, and more preferably 1.0 μm or less, even more preferably 0.8 μm or less. Furthermore, the average particle size D50 of the alumina filler (C) is preferably smaller than the average particle size D50 of the aluminum nitride filler (B).

[0081] When the average particle size D50 of the alumina filler (C) is smaller than the average particle size D50 of the aluminum nitride filler (B), the alumina filler (C) easily penetrates into the gaps between the aluminum nitride fillers (B) in the resin composition film, so that even if the filling rates of the aluminum nitride filler (B) and the alumina filler (C) are increased, the fluidity of the resin composition film tends not to decrease significantly. In addition, the contact area of ​​the thermally conductive particles easily increases, so that the thermal conductivity of the cured product obtained from the resin composition film tends to improve.

[0082] The ratio of the average particle size D50 of the alumina filler (C) to the average particle size D50 of the aluminum nitride filler (B) (average particle size D50 of alumina filler (C) / average particle size D50 of aluminum nitride filler (B)) is preferably 0.02 to 0.9. The ratio is more preferably 0.05 or more, even more preferably 0.10 or more, and more preferably 0.8 or less, even more preferably 0.7 or less. When the ratio is within the above range, the filling properties of the aluminum nitride filler (B) and the alumina filler (C) are improved, and the fluidity of the resin composition film can be improved.

[0083] The maximum particle size Dmax of the alumina filler (C) is preferably 5 μm or less, more preferably 4 μm or less, and even more preferably 3 μm or less. The specific surface area SA of the alumina filler (C) is preferably 1 to 50 m ２ The specific surface area SA is more preferably 1.5 m ２ / g or more, more preferably 2m ２ / g or more, more preferably 30m ２ / g or less, more preferably 20m ２ The alumina filler (C) having a specific surface area SA within the above range is excellent in dispersibility, and tends to improve the fluidity of the resin composition film and also improve the embeddability.

[0084] The higher the crystallinity of the alumina filler (C), the more preferable, and the higher the proportion of alpha crystals in the crystal system, the more preferable. The higher the crystallinity of the alumina filler (C), the more the thermal conductivity of the cured product obtained from the resin composition film tends to improve. The crystallinity of the alumina filler (C) can be confirmed by X-ray diffraction.

[0085] The alumina filler (C) may be an alumina filler that has not been surface-treated with a surface treatment agent. An alumina filler that has not been surface-treated with a surface treatment agent is also referred to as an "untreated alumina filler." Commercially available untreated alumina fillers include, for example, Advanced Alumina AA-03F (manufactured by Sumitomo Chemical Co., Ltd.), Advanced Alumina AA-04 (manufactured by Sumitomo Chemical Co., Ltd.), NXA-100 (manufactured by Sumitomo Chemical Co., Ltd.), NXA-150 (manufactured by Sumitomo Chemical Co., Ltd.), and AHPA-0.5AF (manufactured by Sasol).

[0086] From the viewpoint of embeddability and adhesion of the resin composition film, the alumina filler (C) is preferably an alumina filler that has been surface-treated with a surface treatment agent. The alumina filler that has been surface-treated with a surface treatment agent is also called a "surface-treated alumina filler."

[0087] When the alumina filler (C) is a surface-treated alumina filler, the 10% particle size D10 of the alumina filler before surface treatment with a surface treatment agent is preferably 0.02 to 1.0 μm. The 10% particle size D10 is more preferably 0.05 μm or more, even more preferably 0.08 μm or more, more preferably 0.9 μm or less, and even more preferably 0.7 μm or less. The average particle size D50 of the alumina filler before surface treatment with a surface treatment agent is preferably 0.05 to 1.5 μm. The average particle size D50 is more preferably 0.1 μm or more, even more preferably 0.15 μm or more, more preferably 1.0 μm or less, and even more preferably 0.8 μm or less. The 90% particle size D90 of the alumina filler before surface treatment with a surface treatment agent is preferably 0.1 to 2.0 μm. The 90% particle size D90 is more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and more preferably 1.5 μm or less, even more preferably 1.2 μm or less.

[0088] The 10% particle diameter D10 in the present invention is the particle diameter at the 10% cumulative volume value in the particle size distribution measured by the laser diffraction scattering method. The 90% particle diameter D90 in the present invention is the particle diameter at the 90% cumulative volume value in the particle size distribution measured by the laser diffraction scattering method. The particle size distribution can be measured by the method described in the Examples section below.

[0089] When the alumina filler (C) is a surface-treated alumina filler, the specific surface area SA of the alumina filler before the surface treatment with the surface treatment agent is preferably 1 to 50 m ２ The specific surface area SA is more preferably 1.5 m ２ / g or more, more preferably 2m ２ / g or more, more preferably 30m ２ / g or less, more preferably 20m ２ / g or less.

[0090] Examples of the surface treatment agent include silane compounds such as silane coupling agents, aluminate coupling agents, and titanate coupling agents. Examples of the silane compound include the same silane compounds as those usable for the surface treatment of the aluminum nitride filler (B).

[0091] From the viewpoint of embeddability and adhesion of the resin composition film, the surface treatment agent is preferably a silane compound, more preferably a silane coupling agent having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom.That is, the alumina filler (C) is preferably a surface-treated alumina filler that has been surface-treated with a silane compound, more preferably a surface-treated alumina filler that has been surface-treated with a silane coupling agent (SC2) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom.

[0092] The silane coupling agent (SC2) is a silane compound having a hydrolyzable group and an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, and is preferably an alkoxysilane compound having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom.

[0093] The organic reactive group possessed by the silane coupling agent (SC2) is different from the organic reactive group possessed by the silane coupling agent (SC1). That is, the silane coupling agent (SC2) is a silane coupling agent having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, which is different from the organic reactive group possessed by the silane coupling agent (SC1).

[0094] Examples of the silane coupling agent (SC2) include the same silane coupling agent as the silane coupling agent (SC1). From the viewpoint of embedding property and adhesion property of the resin composition film, the silane coupling agent (SC2) preferably has an organic reactive group containing an oxygen atom or a nitrogen atom, more preferably has an organic reactive group containing an amino group or a (meth)acrylic group of a secondary amine structure, and further preferably has an organic reactive group containing a (meth)acrylic group.

[0095] From the viewpoints of the dispersibility of the filler, the thermal conductivity of the cured product, and the embeddability and adhesiveness of the resin composition film, it is preferred that the aluminum nitride filler (B) is an aluminum nitride filler whose surface has been treated with a silane coupling agent (SC1), and the alumina filler (C) is an alumina filler whose surface has been treated with a silane coupling agent (SC2).

[0096] Since the alumina filler (C) having a small particle size has a large specific surface area, when the alumina filler (C) is a surface-treated alumina filler, the affinity between the alumina filler (C) and the epoxy resin (A) is likely to be improved, and the dispersibility of the alumina filler (C) in the resin composition film is improved.

[0097] Furthermore, since the alumina filler (C) having a small particle size has a large specific surface area, even if the alumina filler (C) is a surface-treated alumina filler, weak aggregation of the alumina filler (C) is likely to occur. Therefore, the melt viscosity η of the resin composition film obtained by dynamic viscoelasticity measurement with a strain of 0.1% ０．１％On the other hand, in the dynamic viscoelasticity measurement at a strain of 10%, the weak cohesion between the alumina filler (C) tends to break easily, and the minimum melt viscosity η １０％ Since the fillability of the resin composition film tends to be excellent, the fillability of the resin composition film tends to be excellent.

[0098] When the surface treatment agent is a silane coupling agent (SC2), particularly when the silane coupling agent (SC2) has an organic reactive group containing a (meth)acrylic group, crosslinking between the (meth)acrylic groups due to thermal polymerization easily occurs, and weak aggregation between the alumina fillers (C) tends to occur. ０．１％ In addition, the crosslinking between (meth)acrylic groups due to thermal polymerization is easily broken under flow with large strain, so the minimum melt viscosity η １０％ The resistance is low and there is little possibility of adversely affecting embeddability.

[0099] When the aluminum nitride filler (B) is an aluminum nitride filler surface-treated with a silane coupling agent (SC1) and the alumina filler (C) is an alumina filler surface-treated with a silane coupling agent (SC2), the organic reactive groups of the silane coupling agent (SC1) and the silane coupling agent (SC2) are different, and therefore the interaction between the silane coupling agents in the aluminum nitride filler (B) and the alumina filler (C) can be alleviated. This improves the filling ability of the filler, thereby improving the fluidity of the resin composition film, and also improves the adhesion between the epoxy resin (A) and the filler, thereby improving the thermal conductivity of the cured product obtained from the resin composition film.

[0100] From the viewpoint of embeddability and adhesion of the resin composition film, the combination of the silane coupling agent (SC1) and the silane coupling agent (SC2) is preferably a combination in which the silane coupling agent (SC1) has an organic reactive group containing a phenylamino group, and the silane coupling agent (SC2) has an organic reactive group containing a (meth)acrylic group.

[0101] When the aluminum nitride filler (B) is an aluminum nitride filler that has been surface-treated with a silane coupling agent (SC1) having an organic reactive group containing a phenylamino group, it has good affinity with and is easily dispersed in the epoxy resin (A). Therefore, the effect of cakeless filtration, which will be described later, is also significant, and the minimum melt viscosity η of the obtained resin composition film is low. １０％ Furthermore, when the alumina filler (C) is an alumina filler that has been surface-treated with a silane coupling agent (SC2) having an organic reactive group containing a (meth)acrylic group, the melt viscosity η ０．１％ In particular, when the alumina filler (C) having a smaller average particle size than the aluminum nitride filler (B) is surface-treated with a silane coupling agent (SC2) having an organic reactive group including a (meth)acrylic group, these effects are more likely to be exhibited, and the embeddability and adhesiveness of the resin composition film are more likely to be improved, which is preferable.

[0102] When the silane coupling agent (SC1) has an organic reactive group containing a phenylamino group, the silane coupling agent (SC2) preferably does not have an organic reactive group containing a phenylamino group.

[0103] The surface treatment with the surface treatment agent can be carried out by a known method, and may be carried out by either a dry surface treatment or a wet surface treatment. The amount of the surface treatment agent used when carrying out the surface treatment is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 4 parts by mass, per 100 parts by mass of the alumina filler before the surface treatment. The alumina filler (C) may be one type or two or more types.

[0104] <Content of Each Component> The resin composition film contains 700 to 1,400 parts by mass of aluminum nitride filler (B) and alumina filler (C) in total relative to 100 parts by mass of epoxy resin (A). The total content of aluminum nitride filler (B) and alumina filler (C) relative to 100 parts by mass of epoxy resin (A) is preferably 750 parts by mass or more, more preferably 800 parts by mass or more, and preferably 1,300 parts by mass or less, more preferably 1,200 parts by mass or less. When the total content of aluminum nitride filler (B) and alumina filler (C) is within the above range, the resin composition film has excellent flowability, and a cured product obtained from the resin composition film has excellent thermal conductivity.

[0105] The mass ratio of the content of the aluminum nitride filler (B) to the content of the alumina filler (C) (content of the aluminum nitride filler (B) / content of the alumina filler (C)) is preferably 95 / 5 to 20 / 80, more preferably 93 / 7 to 30 / 70, and even more preferably 90 / 10 to 40 / 60, from the viewpoint of dispersibility of the filler.

[0106] The ratio of the content of the aluminum nitride filler (B) to the content of the alumina filler (C) is preferably such that the ratio (S2 / S1) of the total surface area S2 of the alumina filler (C) to the total surface area S1 of the aluminum nitride filler (B) is 0.3 to 3.0. The ratio (S2 / S1) is preferably 0.4 or more, more preferably 0.5 or more, and preferably 2.5 or less, more preferably 2.2 or less. By keeping the value of S2 / S1 within the above range, the thermal conductivity of the cured product obtained from the resin composition film can be further increased. Although the reason for this is unclear, it is presumed that the balance of the interactions between the epoxy resin (A) and each filler improves the adhesion at the interface between the epoxy resin (A) and the filler, thereby improving the filler loading.

[0107] The total surface area S1 of the aluminum nitride filler (B) can be calculated by multiplying the specific surface area SA of the aluminum nitride filler (B) by the content of the aluminum nitride filler (B). The total surface area S2 of the alumina filler (C) can be calculated by multiplying the specific surface area SA of the alumina filler (C) by the content of the alumina filler (C).

[0108] <Other Components> The resin composition film may contain components other than the epoxy resin (A), the aluminum nitride filler (B), and the alumina filler (C) (hereinafter also referred to as "other components"), provided that the effects of the present invention are not impaired. Examples of other components include curing agents, curing accelerators, resins other than the epoxy resin (A), fillers other than the aluminum nitride filler (B) and the alumina filler (C), flame retardants, rubber particles, thickeners, defoamers, leveling agents, adhesion promoters, antioxidants, UV inhibitors, and colorants.

[0109] Examples of the curing agent include an epoxy resin curing agent. When the epoxy resin (A) contains a reactive epoxy resin, the epoxy resin curing agent has the function of reacting with the reactive epoxy resin to cure. When the resin composition film contains an epoxy resin curing agent, the cured product obtained by thermally curing the resin composition film tends to have high strength and heat resistance.

[0110] Known curing agents can be used as the epoxy resin curing agent. Examples of epoxy resin curing agents include phenol-based curing agents, naphthol-based curing agents, active ester-based curing agents, cyanate ester-based curing agents, benzoxazine-based curing agents, and acid anhydride-based curing agents. From the viewpoints of the formability of the resin composition film and the heat resistance of the cured product obtained from the resin composition film, phenol-based curing agents, naphthol-based curing agents, and active ester-based curing agents are preferred. The curing agents may be used alone or in combination of two or more.

[0111] As the phenol-based curing agent and naphthol-based curing agent, phenol-based curing agent and naphthol-based curing agent having a novolac structure are preferred from the viewpoint of the heat resistance and water resistance of the cured product obtained from the resin composition film. As the phenol-based curing agent having a novolac structure, phenol novolac, cresol novolac, bisphenol A-type novolac, phenol aralkyl novolac, biphenyl aralkyl novolac, aminotriazine novolac (triazine structure-containing phenol novolac), triphenylmethane novolac, and cyclopentadiene phenol novolac are preferred. As the naphthol-based curing agent having a novolac structure, naphthol aralkyl-type phenol novolac, aralkyl-type naphthol-phenol novolac, and naphthol-cresol-type novolac are preferred.

[0112] Commercially available phenolic curing agents and naphthol curing agents include, for example, "GPH-103," "GPH-65," and "TKG-105" manufactured by Nippon Kayaku Co., Ltd.; "TD-2093," "TD-2090," "LF-6161," "LF-4871," "LA-7052," "LA-7054," "LA-1536," and "LA-1356" manufactured by DIC Corporation; "ZX-798" and "SN485" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "TPM-100" and "GPNX" manufactured by Gun-ei Chemical Co., Ltd.; and "S-TPM" and "J-DDP" manufactured by JFE Chemical Corporation.

[0113] From the viewpoints of formability of the resin composition film and heat resistance of the cured product obtained from the resin composition film, the reactive group equivalent (hydroxyl group equivalent) of the phenol-based curing agent and naphthol-based curing agent is preferably 20 to 4000, more preferably 50 to 2000, and even more preferably 50 to 1000. The hydroxyl group equivalent is the mass of the resin per equivalent of hydroxyl groups.

[0114] Examples of active ester-based curing agents include active ester-based curing agents having a dicyclopentadiene structure, active ester-based curing agents having a naphthalene structure, active ester-based curing agents containing an acetylated product of phenol novolac, and active ester-based curing agents containing a benzoylated product of phenol novolac. From the viewpoint of the heat resistance and water resistance of the cured product obtained from the resin composition film, active ester-based curing agents having a dicyclopentadiene structure and active ester-based curing agents having a naphthalene structure are preferred. An example of a commercially available active ester-based curing agent having a dicyclopentadiene structure is "HPC-8000-65T" manufactured by DIC Corporation. An example of a commercially available active ester-based curing agent having a naphthalene structure is "HPC-8150-62T" manufactured by DIC Corporation.

[0115] From the viewpoints of the moldability of the resin composition film and the heat resistance of the cured product obtained from the resin composition film, the reactive group equivalent (active ester group equivalent) of the active ester curing agent is preferably 50 to 2000, more preferably 50 to 1000, and even more preferably 100 to 500. The active ester group equivalent is the mass of resin per equivalent of active ester group.

[0116] The content of the curing agent in the resin composition film is preferably 50 to 200 parts by mass per 100 parts by mass of the epoxy resin (A) from the viewpoint of the heat resistance and mechanical strength of the cured product obtained from the resin composition film. The content of the curing agent is more preferably 65 parts by mass or more, even more preferably 75 parts by mass or more, more preferably 150 parts by mass or less, and even more preferably 125 parts by mass or less. The total number of reactive groups, such as hydroxyl groups and active ester groups, in the curing agent is preferably 0.5 to 2 relative to the total number of epoxy groups in the epoxy resin (A). The total number of reactive groups is more preferably 0.6 or more, even more preferably 0.65 or more, more preferably 1.5 or less, and even more preferably 1.25 or less. The total number of epoxy groups in the epoxy resin (A) is the sum of the values ​​obtained by dividing the mass of each epoxy resin by the epoxy equivalent for all epoxy resins. Similarly, the total number of reactive groups in the curing agent is the sum of the values ​​obtained by dividing the mass of each curing agent by the reactive group equivalent.

[0117] Examples of the curing accelerator include an epoxy resin curing accelerator. An epoxy resin curing accelerator functions to promote the reaction between the epoxy groups of the epoxy resin (A) and the reactive groups of the curing agent, and to promote the polymerization of the epoxy groups. When the epoxy resin (A) contains a reactive epoxy resin, the resin composition film can be easily thermally cured by including an epoxy resin curing accelerator, and the cured product tends to have high strength. The content of the epoxy resin curing accelerator in the resin composition film is preferably 0.01 to 5 parts by mass per 100 parts by mass of the epoxy resin (A). The content of the epoxy resin curing accelerator is more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, and more preferably 3 parts by mass or less, even more preferably 2 parts by mass or less.

[0118] The epoxy resin curing accelerator may be any known one without particular limitation, and examples thereof include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, and guanidine-based curing accelerators, with amine-based curing accelerators and imidazole-based curing accelerators being preferred. The curing accelerators may be used alone or in combination of two or more.

[0119] Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0120] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole. nirimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1 ')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-fu Examples of the epoxy resin include imidazole compounds such as 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, 2-methylimidazoline, and 2-phenylimidazoline, as well as adducts of imidazole compounds with epoxy resins.

[0121] Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

[0122] Examples of guanidine curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, and 1-(o-tolyl)biguanide.

[0123] When the resin composition film contains a resin other than the epoxy resin (A) (hereinafter also referred to as "other resin"), the resin composition film tends to have excellent flexibility. Therefore, when the resin composition film is molded, the coating property is improved to obtain a uniform film, and the film becomes flexible, improving winding properties. In addition, the impact resistance of the cured product obtained from the resin composition film is improved, making the cured product less likely to crack.

[0124] Examples of the other resin include thermoplastic resins such as phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polyphenylene ether resin, and polysulfone resin, and among these, phenoxy resin, which has a structure similar to that of the epoxy resin (A), is preferred because it has good compatibility with the epoxy resin (A). The other resin may be used alone or in combination of two or more.

[0125] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any terminal structure such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone or in combination of two or more types.

[0126] Commercially available phenoxy resins containing a bisphenol acetophenone skeleton include, for example, "YX6954BH30" manufactured by Mitsubishi Chemical Corporation. Commercially available phenoxy resins containing a bisphenol S skeleton include, for example, "YX8100BH30" manufactured by Mitsubishi Chemical Corporation. Commercially available phenoxy resins include, for example, "YX7553BH30" manufactured by Mitsubishi Chemical Corporation.

[0127] The weight-average molecular weight of the phenoxy resin is preferably 5,000 to 10,000. The weight-average molecular weight of the phenoxy resin is a weight-average molecular weight in terms of polystyrene measured by gel permeation chromatography. The content of the other resin, such as the phenoxy resin, in the resin composition film is preferably 0.1 to 50 parts by mass per 100 parts by mass of the epoxy resin (A). The content of the other resin is more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less.

[0128] Fillers other than the aluminum nitride filler (B) and the alumina filler (C) (hereinafter also referred to as "other fillers") are fillers made of materials other than aluminum nitride and alumina. Examples of other fillers include silica, zinc oxide, magnesium oxide, titanium oxide, silicon nitride, boron nitride, aluminum hydroxide, magnesium hydroxide, silicon carbide, calcium carbonate, barium sulfate, talc, and diamond.

[0129] The content of the other filler in the resin composition film is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the total amount of the aluminum nitride filler (B) and the alumina filler (C). It is particularly preferred that the resin composition film does not contain any other filler. The average particle size D50 of the other filler is preferably smaller than the average particle size D50 of the aluminum nitride filler (B), more preferably less than 2 μm, and even more preferably less than 1.5 μm. The maximum particle size Dmax of the other filler is preferably smaller than the maximum particle size Dmax of the aluminum nitride filler (B), more preferably less than 4.5 μm, and even more preferably less than 4 μm.

[0130] The flame retardant imparts flame retardancy to the resin composition film when it is used in a semiconductor product. Examples of the flame retardant include organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, and metal hydroxides. The flame retardants may be used alone or in combination of two or more.

[0131] When the resin composition film contains rubber particles, the internal stress generated when the resin composition film is thermally cured is alleviated, and warping of the cured product is reduced, so that the impact resistance of the cured product tends to be excellent. Examples of the rubber particles include fine particles such as core-shell rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, and acrylic rubber particles. The average particle size D50 of the rubber particles is preferably 1 μm or less, more preferably 0.8 μm or less.

[0132] [Method for producing resin composition film] The resin composition film can be produced by, for example, preparing a varnish by mixing the epoxy resin (A), the aluminum nitride filler (B), the alumina filler (C), an organic solvent, and, if necessary, the other components, using a known method such as a blender or mixer, then applying the varnish to a support using a die coater or the like, drying the varnish by heating, blowing hot air, or the like, and removing the organic solvent so that the amount of remaining solvent falls within the above-mentioned range.

[0133] During the mixing, the components may be simultaneously added to a mixer or the like and mixed, or the components may be added sequentially to a mixer or the like and mixed. The order of addition when the components are added sequentially to a mixer or the like is not particularly limited. Furthermore, the mixing may be performed under heating, or in a controlled atmosphere such as an inert gas atmosphere, as necessary.

[0134] Examples of the organic solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, N,N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone, and solvent naphtha, which is a mixture thereof. The organic solvents may be used alone or in combination of two or more.

[0135] From the viewpoint of ease of removal of the organic solvent during drying, the boiling point of the organic solvent is preferably 200° C. or lower, more preferably 180° C. or lower. The content of the organic solvent in the varnish is not particularly limited and may be appropriately adjusted taking into consideration factors such as coatability onto a support.

[0136] The varnish tends to generate gel components formed by the composite of the filler and the epoxy resin (A), etc. When the resin composition film contains such gel components, the minimum melt viscosity η １０％The viscosity of the resin composition film tends to increase, resulting in a decrease in the fluidity of the resin composition film. It is difficult to remove this gel content even when filtered through a filter with large openings. Furthermore, when the varnish is filtered through a filter with small openings, the gel content forms a gel-like filter cake on the filter, preventing the filtrate from passing through the filter. Therefore, it is preferable to perform cakeless filtration of the varnish in order to break down the gel content.

[0137] Cakeless filtration is a filtration method that sweeps away particles that reach the cake surface during the filtration operation, thereby preventing cake growth as much as possible. By performing cakeless filtration, it is possible to crush the gel component, which is a composite of the filler and the resin component contained in the resin composition film, and therefore, even if the amount of remaining solvent is small, the minimum melt viscosity η １０％ Therefore, the embeddability of the resin composition film tends to be improved.

[0138] Examples of cakeless filtration include crossflow filtration, in which the slurry is made to flow at high speed parallel to the filter surface, sweeping away particles that reach the cake surface; rotating disk filtration, in which a disk is placed inside the filter and rotated at high speed to generate high shear force; rotating cylinder filtration, in which the slurry is forced between two coaxial cylinders and the cylinders are rotated at high speed, to generate Taylor vortex flows; and vibration filtration, in which a plate is vibrated parallel to the membrane surface near the membrane surface. Further examples of cakeless filtration include a method in which shear force is applied parallel to the filter surface with a resin spatula or the like, thereby breaking down the cake while performing filtration.

[0139] From the viewpoint of embeddability of the resin composition film, the mesh size of the filter used for cakeless filtration is preferably smaller than that of the filter used for filtration performed for the purpose of removing foreign matter, etc., and specifically, it is preferably 50 μm or less, particularly preferably 30 μm or less. In filtration of varnish, it is also a preferred method to perform ordinary filtration for the purpose of removing foreign matter and aggregates, and then perform the cakeless filtration.

[0140] The cakeless filtered varnish can be formed into a film by a conventionally known method. A particularly suitable method is, for example, to coat the varnish on a support using a die coater, knife coater, comma coater, or gravure coater, and then dry the organic solvent by heating and hot air blowing, etc., to produce a resin composition film. It is preferable to dry the varnish coated on the support so that the amount of remaining solvent in the resin composition film falls within the above-mentioned range. Although this varies depending on the boiling point of the organic solvent contained in the resin composition film, for example, by heating and drying the varnish at 60°C to 150°C for 1 to 15 minutes, a resin composition film that is not excessively heat-cured can be obtained.

[0141] The resin composition film is preferably in a partially cured state, a so-called B-stage film. When the resin composition film is in a partially cured state, the resin composition film is not completely cured. Therefore, when manufacturing a multilayer printed wiring board or a component-embedded board, the resin composition film can conform to the shape of the conductor layer. Further curing of the resin composition film can then be advanced to improve the strength and durability of the resin composition film. When stored as a B-stage film, it is preferably stored at 10°C or below, more preferably at 0°C or below, and even more preferably at -10°C or below, in order to prevent changes in the physical properties of the film.

[0142] As the support, various plastic films can be suitably used, for example, polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate film, olefin films such as polyethylene film and polypropylene film, and polyimide film, among which polyethylene terephthalate film is preferred because it has excellent smoothness and heat resistance and is inexpensive.

[0143] From the viewpoints of wettability during coating of the resin composition film and releasability during the production of various semiconductor substrates, the coated surface of the plastic film support may be subjected to a release treatment, matte treatment, corona discharge treatment, etc. Metal foils such as copper foil and aluminum foil may be used as the support. Suitable copper foils include rolled copper foil and electrolytic copper foil. Using a metal foil as the support can eliminate the step of laminating the metal foil during the production of various substrates, thereby improving the adhesive strength between the support and the resin composition film. The thickness of the support is not particularly limited, but is preferably in the range of 5 to 150 μm, more preferably 10 to 100 μm, and even more preferably 10 to 60 μm.

[0144] A protective film similar to the support may be further laminated on the surface of the resin composition film that is not in contact with the support. The thickness of the protective film is not particularly limited, but is, for example, 5 to 40 μm. By laminating a protective film on the surface of the resin composition film that is not in contact with the support, adhesion of dust and the like to the surface of the resin composition film and scratches can be prevented, and the resin composition film can also be wound into a roll. When producing multilayer printed wiring boards, component-embedded substrates, and other semiconductor materials, the protective film is peeled off before use.

[0145] [Uses of Resin Composition Film] The resin composition film has excellent embeddability and adhesion, and the cured product obtained from the resin composition film has high thermal conductivity, so the resin composition film can be suitably used as an insulating layer for a multilayer printed wiring board and an encapsulating resin film for a component-embedded substrate. In addition to these uses, the resin composition film can also be used in a wide range of applications requiring heat dissipation, such as adhesive films, insulating layers for metal-clad laminates, insulating resin sheets such as prepregs, underfill materials, die bonding materials, semiconductor encapsulants, and hole-filling resins.

[0146] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0147] The following components were used as materials for the resin composition. <Epoxy Resins> Solid Epoxy Resin (A-1) The following solid epoxy resin was dissolved in methyl ethyl ketone to prepare a 50% by mass solution. EPPN-501HY (manufactured by Nippon Kayaku Co., Ltd., trisphenolmethane type epoxy resin, epoxy equivalent 166, softening point 60°C) Liquid Epoxy Resin (A-2) jER828 (manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent 189, viscosity (25°C) 135 poise)

[0148] <Aluminum nitride filler (B)> <Untreated aluminum nitride filler> HF-01D (manufactured by Tokuyama Corporation) Untreated aluminum nitride fillers were surface-treated with a silane coupling agent (SC1) by the following method and used as aluminum nitride fillers (B-1) to (B-3). Combinations of untreated aluminum nitride fillers and silane coupling agents (SC1) are shown in Table 2.

[0149] <Method for producing aluminum nitride filler (B)> 600 g of untreated aluminum nitride filler, 5 g of silane coupling agent (SC1), and 1,200 g of isopropyl alcohol were placed in a glass eggplant flask and stirred for 30 minutes with a fluororesin stirring blade. Subsequently, the isopropyl alcohol was removed under reduced pressure at 50°C using a rotary evaporator, and the resulting mixture was dried under reduced pressure at 100°C to perform a surface treatment.

[0150] <Alumina Filler (C)> <Untreated Alumina Filler> AA-03F (manufactured by Sumitomo Chemical Co., Ltd.) AHPA-0.5AF (manufactured by Sasol) NXA-150 (manufactured by Sumitomo Chemical Co., Ltd.) AA-04 (manufactured by Sumitomo Chemical Co., Ltd.)

[0151] The alumina fillers (C-1) to (C-7) were untreated alumina fillers that were surface-treated with a silane coupling agent (SC2) by the following method. Table 3 shows the combinations of untreated alumina fillers and silane coupling agents (SC2).

[0152] <Method for producing alumina filler (C)> 600 g of untreated alumina filler, 5 g of a silane coupling agent (SC2), and 1,200 g of isopropyl alcohol were placed in a glass eggplant flask and stirred for 30 minutes with a fluororesin stirring blade. Next, the isopropyl alcohol was removed under reduced pressure at 50°C using a rotary evaporator, and the mixture was then dried under reduced pressure at 100°C to perform a surface treatment.

[0153] <Silane coupling agent (SC1) and silane coupling agent (SC2)> N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-573) 3-methacryloxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-503) 3-glycidoxypropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBE-403) 3-acryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-5103)

[0154] <Curing Agent> The following curing agent was dissolved in methyl ethyl ketone and used as a 50% by mass solution: GPH-103 (manufactured by Nippon Kayaku Co., Ltd., biphenylaralkylphenol novolak, hydroxyl equivalent 230, softening point 103°C)

[0155] <Phenoxy Resin> YX6954BH30 (manufactured by Mitsubishi Chemical Corporation, bisphenolacetophenone skeleton-containing phenoxy resin, weight average molecular weight 40670, non-volatile content 30% by mass, cyclohexanone / methyl ethyl ketone (1 / 1) solution)

[0156] <Curing accelerator> 4-dimethylaminopyridine (DMAP, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0157] [Evaluation of Filler Properties] The physical properties of the untreated alumina filler, aluminum nitride filler (B) and alumina filler (C) were measured under the following conditions. The measurement results are shown in Tables 1 to 3.

[0158] <Filler Particle Size> Untreated alumina filler, aluminum nitride filler (B), or alumina filler (C) was added to a dispersion medium to a concentration of 0.2% by mass, and the sample was dispersed by irradiating it with ultrasonic waves of about 200 W for 2 minutes. The particle size distribution of the sample was measured using a laser diffraction / scattering particle size distribution meter (MICROTRACK-MT3300EXII, manufactured by Microtrack-Bell Co., Ltd.). Water was used as the dispersion medium when dispersing untreated alumina filler, and ethanol was used when dispersing surface-treated aluminum nitride filler or surface-treated alumina filler. In the obtained volume frequency distribution of particle sizes (particle size distribution), the volume frequency was accumulated from the smallest particle size, and the particle size at which the cumulative value reached 10% was defined as the 10% particle size diameter D10, the particle size at which the cumulative value reached 50% was defined as the average particle size D50, the particle size at which the cumulative value reached 90% was defined as the 90% particle size diameter D90, and the maximum particle size value measured (particle size at 100% cumulative volume) was defined as the maximum particle size Dmax.

[0159] <Specific Surface Area of ​​Filler> The specific surface areas SA of the untreated alumina filler, aluminum nitride filler (B), and alumina filler (C) were determined by the BET method (nitrogen adsorption single-point method) using a flow-type automatic specific surface area measuring device (Shimadzu Corporation, Flowsorb II-2300). For the measurement, 2 g of powdered untreated alumina filler, aluminum nitride filler (B), or alumina filler (C) dried at 100°C for 1 hour under a nitrogen gas flow was used.

[0160]

[0161]

[0162]

[0163] [Example 1] 0.8 parts by mass of the curing accelerator DMAP was dissolved in 100 parts by mass of a methyl ethyl ketone solution of solid epoxy resin (A-1) EPPN-501HY (non-volatile content 50 parts by mass), and then 50 parts by mass of liquid epoxy resin (A-2) jER828 and 16.7 parts by mass of phenoxy resin solution YX6954BH30 (non-volatile content 5 parts by mass) were added and stirred for 10 minutes using a homodisper. Next, 402 parts by mass of alumina filler (C-1) was added and thoroughly mixed for 3 minutes, after which 174 parts by mass of a methyl ethyl ketone solution of curing agent GPH-103 (non-volatile content 87 parts by mass) and 230 parts by mass of cyclohexanone were added and stirred for 10 minutes using a homodisper. Finally, 670 parts by mass of aluminum nitride filler (B-1) was added in five batches, and the mixture was stirred for 30 minutes using a homodisper. During the stirring, cyclohexanone was appropriately added to adjust the viscosity. After the stirring was completed, the mixture was degassed under vacuum for 30 minutes. In order to remove filler aggregates and foreign matter, the mixture was filtered using a mesh filter with an opening of 100 μm to obtain a filtrate.

[0164] The filtrate was further filtered using a mesh filter with 30 μm openings. When filtering using the 30 μm mesh filter, a gel-like filter cake grew on the filter, preventing the filtrate from passing through the filter. Therefore, shear force was applied parallel to the filter surface using a resin spatula or the like to crush the cake while filtering. By the above operations, a varnish of the resin composition was prepared.

[0165] Next, the varnish of the resin composition was uniformly applied to the release-treated surface of a support (release-treated polyethylene terephthalate film (manufactured by Fujimori Kogyo Co., Ltd., BYNA NSP-5, thickness 38 μm)) so that the thickness after drying would be 40 μm, and the film was dried at 70°C for 150 seconds using a safety oven to produce a resin composition film (B stage). Note that since the drying state differs depending on the filler content and resin composition, in Examples 2 to 15 and Comparative Examples 1 to 7, the amount of remaining solvent in the resin composition film prepared in advance was measured by the method described below, and the drying temperature and drying time were appropriately adjusted so as to fall within the desired range.

[0166] The rough side of a polypropylene film (manufactured by Oji F-Tex Co., Ltd., Alphan MA-411, thickness 15 μm) was attached as a protective film to the surface of the resin composition film opposite to the surface facing the support, thereby producing a laminate (1) in which the support, resin composition film, and protective film were laminated in this order.

[0167] <Measurement of Residual Solvent Amount> The resin composition film laminated on the support was cut into a 10 cm square together with the support, and its mass A was measured. Next, this 10 cm square resin composition film was dried at 130°C for 15 minutes, and its mass B was measured again. The release-treated polyethylene terephthalate film (manufactured by Fujimori Kogyo, BYNA NSP-5, thickness 38 μm) used as the support was cut into a 10 cm square, and its mass C was measured. The residual solvent amount was calculated by applying the measured masses A to C to the following formula: Residual Solvent Amount (%) = (A - B) / (A - C) x 100

[0168] [Examples 2 to 15, Comparative Examples 4 to 7] Resin composition films were produced in the same manner as in Example 1, except that the composition of the resin composition film was changed as shown in Tables 4 to 6, and the amount of residual solvent was changed by changing the drying temperature and drying time.

[0169] Comparative Examples 1 to 3 Resin composition films were produced in the same manner as in Example 1, except that the composition of the resin composition film was changed as shown in Table 6, the amount of residual solvent was changed by changing the drying temperature and drying time, and filtration using a mesh filter with an opening of 30 μm was not performed.

[0170] [Evaluation of Physical Properties of Resin Composition] Tables 4 to 6 show the results of measuring the physical properties of the resin composition film under the following conditions.

[0171] <Melt Viscosity> The protective film was peeled off from the laminate (1), and the resin composition film was peeled off from the support. The melt viscosity of the resin composition film was measured using a viscoelasticity measuring device (rotational rheometer) (MCR302e, manufactured by Anton Paar). The measurement conditions for the dynamic viscoelasticity measurement were: geometry: parallel plates with a diameter of 10 mm, gap: 1 mm, temperature range: 60°C to 180°C, frequency: 1 Hz, strain: 10%. The minimum value of the complex viscosity in the obtained dynamic viscoelasticity measurement results was taken as the minimum melt viscosity η １０％ The complex viscosity is the minimum melt viscosity η １０％ The temperature at which the strain was 0.1% was defined as the minimum melt viscosity temperature. The dynamic viscoelasticity measurement was carried out in the same manner as above, except that the strain was set to 0.1%, and the complex viscosity value at the minimum melt viscosity temperature was defined as the melt viscosity η ０．１％ It was decided.

[0172] <Thermal Conductivity> After preparing two laminates (1), the protective films were peeled off from each laminate, and the two laminates (1) were stacked together so that the resin composition films overlapped each other, and the stacks were pressure-bonded at 100°C to produce a laminate (2). Thereafter, the support located on the surface of the laminate (2) was peeled off, and a laminate (3) in which two resin composition films were stacked was produced. The laminate (3) was heat-treated at 180°C for 90 minutes to be thermally cured, and a sheet-like cured product was obtained.

[0173] The thermal conductivity (W / m K) of the obtained cured product was ２ / sec) x density (kg / m ３ ) × specific heat (J / kg K). Thermal diffusivity was measured by the xenon flash method (laser flash method, ISO22007-4) using a tabletop thermal diffusivity / thermal conductivity measuring device (NETZSCH, Xenon Flash Analyzer LFA467 HyperFlash). Both sides of the cured product were gold coated and graphite sprayed, and thermal diffusivity measurements were performed with a charge voltage of 200 V and a pulse width of 20 μsec.

[0174] The density was measured by the Archimedes method using an analytical balance (XS204V, manufactured by Mettler Toledo Co., Ltd.), and the specific heat was measured using a differential scanning calorimeter (Thermo Plus Evo DSC8230, manufactured by Rigaku Corporation).

[0175] <Embeddability> After peeling the protective film from the laminate (1), the resin composition film was superimposed on a substrate on which a 35 μm thick copper pattern was formed (copper pattern residual copper ratio 75%, minimum pore size 120 μm), and after depressurizing at 40 ° C for 60 seconds using a vacuum heating press, it was pressed at 0.7 MPa. Next, the resin composition film was pressed at a temperature of 100 ° C and a pressure of 5 MPa for 50 seconds to embed the resin composition film into the substrate. Thereafter, the support was peeled from the resin composition film, and the resin composition film and the substrate were heated in an oven at 180 ° C for 30 minutes to cure the resin.

[0176] The back surface of the substrate (the surface opposite to the surface facing the resin composition film) was illuminated and visually observed, and a cross section of the substrate was cut out and observed under a scanning electron microscope to confirm the presence or absence of voids of 10 μm or more. Ten random fields of view were observed under the scanning electron microscope. Those in which no voids were observed were rated "B," and those in which at least one void was observed were rated "C."

[0177] For those rated "B", the resin composition film was embedded in the same manner as above except that the temperature was 100°C and the pressure was 4 MPa, and those in which no voids were observed were rated "A". Those with an embeddability rating of "A" or "B" were deemed to have passed. Those rated "A" were superior to those rated "B".

[0178] <Adhesion> After peeling the protective film from the laminate (1), the resin composition film was superimposed on a substrate on which a 35 μm-thick copper pattern had been formed (copper pattern residual copper ratio: 75%, minimum pore size: 120 μm), and the resin composition film was attached to the substrate by applying pressure for 60 seconds under conditions of a hot plate temperature of 100° C. and a pressure of 1 MPa. Thereafter, the support was peeled from the resin composition film, and the resin composition film and the substrate were heated in an oven at 180° C. for 30 minutes to cure the resin.

[0179] The resin composition film attached to the substrate was visually observed to check the state of swelling. Those without swelling were rated as "B", and those with confirmed swelling were rated as "C".

[0180] For those rated "B", the resin composition film was attached in the same manner as above except that the hot plate temperature was 120°C and the pressure was 1 MPa, and those for which no blistering was observed were rated "A". Those with an attachment rating of "A" or "B" were deemed to have passed. Those rated "A" were superior to those rated "B".

[0181]

[0182]

[0183]

Claims

1. An epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), wherein the total amount of the aluminum nitride filler (B) and the alumina filler (C) is 700 to 1,400 parts by mass per 100 parts by mass of the epoxy resin (A), the epoxy resin (A) comprises a solid epoxy resin (A-1) and a liquid epoxy resin (A-2), the amount of residual solvent is 3.5% or less, the minimum melt viscosity temperature determined by dynamic viscoelasticity measurement at a strain of 10%, a frequency of 1 Hz, and a temperature range of 60 to 180°C is in the range of 85 to 130°C, and the minimum melt viscosity η １０％ is in the range of 1,000 to 10,000 poise, and the melt viscosity η at the minimum melt viscosity temperature is determined by dynamic viscoelasticity measurement at a strain of 0.1%, a frequency of 1 Hz, and a temperature range of 60 to 180°C. ０．１％ A resin composition film having a viscosity in the range of 300,000 to 2,000,000 poise.

2. The resin composition film according to claim 1, wherein the aluminum nitride filler (B) has an average particle size D50 of 0.2 to 3 μm and a maximum particle size Dmax of 5 μm or less, the alumina filler (C) has an average particle size D50 of 0.05 to 1.5 μm, and the average particle size D50 of the alumina filler (C) is smaller than the average particle size D50 of the aluminum nitride filler (B).

3. A resin composition film according to claim 2, wherein the aluminum nitride filler (B) is a surface-treated aluminum nitride filler that has been surface-treated with a silane coupling agent (SC1) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, and the alumina filler (C) is a surface-treated alumina filler that has been surface-treated with a silane coupling agent (SC2) having an organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom, which is different from the organic reactive group possessed by the silane coupling agent (SC1).

4. The resin composition film according to claim 3, wherein the silane coupling agent (SC1) has an organic reactive group containing an amino group of a secondary amine structure.

5. The resin composition film according to claim 3, wherein the silane coupling agent (SC1) has an organic reactive group containing a phenylamino group.

6. The resin composition film according to claim 3, wherein the silane coupling agent (SC2) has an organic reactive group containing a (meth)acrylic group.

7. A multilayer printed wiring board comprising the resin composition film according to any one of claims 1 to 6 or a cured product thereof.

8. A component-embedded substrate comprising the resin composition film according to any one of claims 1 to 6 or a cured product thereof.

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