Resin composition film

Abstract

To provide a resin composition film having good embedding property and sticking property and high thermal conductivity.SOLUTION: A total amount of the aluminum nitride filler (B) and the alumina filler (C) is 700 to 1400 parts by mass with respect to 100 parts by mass of the epoxy resin (A), the epoxy resin (A) contains a solid epoxy resin and a liquid epoxy resin, an amount of residual solvents is 3.5% or less, and a minimum melt viscosity temperature determined by dynamic viscoelasticity measurement with a strain of 10%, a frequency of 1Hz, and a temperature range of 60 to 180 °C is in a range of 85 to 130 °C, A minimum melt viscosity η10% is in a range of 1,000 to 10, 000poise, and a melt viscosity η0.1% at a minimum melt viscosity temperature obtained by dynamic viscoelasticity measurement at a strain of 0.1% is in a range of 300000 to 2000, 000poise.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As electronic devices become more compact and sophisticated, the wiring density of multilayer printed wiring boards (MLBs) is becoming increasingly finer and denser. A known manufacturing technique for multilayer printed wiring boards is the semi-additive method, which involves alternately stacking insulating and conductor layers. By using a resin composition film for the insulating layer, the insulating layer can be formed efficiently. For the resin composition film, a resin composition containing a thermosetting epoxy resin and silica is generally used (Patent Document 1). The insulating layer is generally formed by overlapping the resin composition film on a 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, which embeds electronic components inside the substrate using encapsulating resin rather than previously mounted on the surface, is also attracting attention. Cavities are formed in the core of the resin substrate and 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. This encapsulating resin can also be a resin composition film, such as that used in multilayer printed wiring boards. 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 using a resin composition film 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, as electronic devices have become smaller and more powerful, the density and packaging of semiconductor elements on multilayer printed wiring boards and component-embedded boards has increased. As a result, the amount of heat generated by semiconductor elements has also increased, making it important to efficiently dissipate that heat from the board. Therefore, in order to address these issues, it has been proposed to use a high thermal conductivity resin composition that uses aluminum nitride, which has higher thermal conductivity than silica, as the resin composition film in the manufacture of multilayer printed wiring boards using the build-up method (Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-132507 [Patent Document 2] International Publication No. 2014 / 208352 Summary of the Invention [Problem to be solved by the invention]

[0008] If the filling rate of the thermally conductive filler is increased in order to improve the thermal conductivity of the cured product obtained from the resin composition film, the fluidity of the resin composition film decreases, and the embeddability decreases. If the amount of solvent remaining in the resin composition film is increased in order to improve the fluidity of the resin composition film, voids are likely to occur due to the evaporation of the remaining solvent when the resin composition film is embedded in a substrate, etc. Furthermore, if the amount of remaining solvent is increased, the tackiness of the resin composition film increases, which makes it more likely to trap air when the resin composition film is attached to a substrate, etc., and therefore makes it more likely to cause blistering. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a resin composition film having high thermal conductivity, which has good embeddability and adhesiveness. [Means for solving the problem]

[0009] The present invention relates to, for example, the following [1] to [8]. [1] Contains an epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), The epoxy resin (A) contains 700 to 1400 parts by mass of the aluminum nitride filler (B) and the alumina filler (C) in total, relative to 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 residual solvent amount 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, 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% is in the range of 300,000 to 2,000,000 poise, Resin composition film.

[0010] [2] 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, The resin composition film according to [1], wherein 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 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; The resin composition film according to [1] or [2], wherein 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, 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. [Effects of the Invention]

[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. DETAILED DESCRIPTION OF THE INVENTION

[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 comprises 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) 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 is in the range of 85 to 130°C 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, 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% 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, preferably 2.0 to 3.3%, and more preferably 2.4 to 3.2%. 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] If the amount of residual solvent is within the above range, the generation of voids resulting from the entrapment of volatile solvent is suppressed when the resin composition film is embedded in a substrate, etc., and therefore the resin composition film has excellent embeddability. Furthermore, if the amount of residual solvent is within the above range, the tackiness of the resin composition film tends to be low, and since the entrapment of air is suppressed when the resin composition film is adhered to a substrate, etc., swelling is less likely to occur, and the resin composition film has excellent adhesion properties. The amount of the remaining solvent in the resin composition film can be adjusted, for example, by adjusting the drying temperature, drying time, air volume, etc. of the resin composition film when producing the resin composition film.

[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% is in the range of 1,000 to 10,000 poise, preferably 2,000 to 8,000 poise, and more preferably 3,000 to 7,000 poise. 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 will have excellent embeddability. Minimum melt viscosity η 10% When the resin composition film has a thickness of 1000 Å, the resin composition film has high fluidity and excellent embeddability. For example, by performing cakeless filtration in the production process of the resin composition film, the minimum melt viscosity η 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 in the range of 85 to 130° C., preferably 95 to 125° C., and more preferably 100 to 120° C. 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 a multilayer printed wiring board or a component-embedded substrate can be set to a temperature around the minimum melt viscosity temperature, allowing the resin composition film to be handled under conditions where the resin composition film has high fluidity.

[0026] The minimum melt viscosity temperature can be adjusted by changing the composition of the resin composition film, for example, 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% is in the range of 300,000 to 2,000,000 poise, preferably 350,000 to 1,500,000 poise, and more preferably 400,000 to 1,000,000 poise. 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 η0.1% When the thickness is within the above range, the tackiness of the resin composition film is low and the resin composition film has excellent adhesion properties. Melt viscosity η 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, and even more preferably 100 or more, and is preferably 200 or less, and 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.

[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 the xenon flash method.

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

[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 based on 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, after being converted into a desired shape, is heat-cured to produce a cured product with high strength and heat resistance, thereby improving the reliability of the substrate. There is no particular upper limit to the content of the reactive epoxy resin in the total amount of the epoxy resin (A), and all of the 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 liquid epoxy resin (A-2) having high fluidity in combination with the solid epoxy resin (A-1) having high heat resistance, and the resin composition film can conform to the desired substrate shape.

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

[0040] Examples of tetrafunctional naphthalene type epoxy resins include "HP-4700" and "HP-4710" manufactured by DIC Corporation. Examples of cresol novolac 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 type 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. An example of the bixylenol type epoxy resin is "YX4000HK" manufactured by Mitsubishi Chemical Corporation. An example of the fluorene-type epoxy resin is "YL7800" manufactured by Mitsubishi Chemical Corporation.

[0044] The softening point of the solid epoxy resin (A-1) is preferably 40 to 130°C, more preferably 45 to 110°C, and even more preferably 50 to 100°C, from the viewpoint of formability of the resin composition film. 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), and examples thereof 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, with methyl ethyl ketone being 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 solvents may be used alone or in combination of two or more.

[0046] The content of nonvolatile matter in the composition is preferably 20 to 90 mass %, more preferably 30 to 80 mass %, and even more preferably 40 to 70 mass %, from the viewpoint of the solubility of the solid epoxy resin (A-1) in organic solvents. In this specification, the term "non-volatile content" 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 the resin composition film may contain.

[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 board, 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. As the liquid epoxy resin (A-2), bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin and naphthalene type epoxy resin are preferred, and bisphenol A type epoxy resin and bisphenol F type epoxy resin are more preferred.

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

[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, and even more preferably 10 to 200 poise. 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 the 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, still more preferably 80 to 2000, and particularly preferably 100 to 1000. 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 K 7236. The epoxy equivalent is the mass of resin per equivalent of epoxy groups.

[0054] <Aluminum nitride filler (B)> The resin composition film contains an aluminum nitride filler (B). When the resin composition film contains an 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, more preferably 0.5 to 1.5 μm. When the average particle size D50 of the aluminum nitride filler (B) is within this range, the resin composition film can be easily formed to a thickness of approximately 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 substrates, the resin composition film has excellent conformability to the complex shapes of conductor layers and cavities and narrow gaps. Furthermore, cured products obtained from films having a thickness within this range tend to have high thermal conductivity. The average particle size D50 in the present invention is the particle size at a cumulative 50% value on a volume basis in the particle size distribution measured by a laser diffraction scattering method. 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 (particle size at 100% cumulative volume) measured in the particle size distribution measured by a laser diffraction scattering method. 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 / g, more preferably 0.8 to 7m 2 / g, more preferably 1.0 to 5m 2 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, or 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 Corp.). 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 also 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. Examples of methods for producing the untreated aluminum nitride filler include 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 the surface treatment agent, the water resistance of the aluminum nitride filler is improved and its affinity with the epoxy resin (A) is improved, which in turn improves the packing property of the aluminum nitride filler and the fluidity of the resin composition film.

[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 silane compounds 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, 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 groups are directly bonded to the silicon atom and include, for example, alkoxy groups such as methoxy and ethoxy groups. The organic reactive group containing an oxygen atom, a nitrogen atom, or a sulfur atom refers to a substituent other than a hydrolyzable group that contains a reactive functional group containing an oxygen atom, a nitrogen atom, or a sulfur atom and is bonded to a silicon atom. The reactive functional group containing an oxygen atom, a nitrogen atom, or a 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, 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 amino group include an amino group represented by the following formula: R 1 and R 2 R each independently represents a hydrogen atom, an alkyl group, or an aryl group. 1 and R 2 The number of carbon atoms in the alkyl group represented by R is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10. The alkyl group may be linear, branched, or cyclic. 1 and R 2 The aryl group represented by the formula (I) 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 a sulfur atom include a mercapto group, a sulfide group, a sulfo group, and a sulfonyl group. 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] As the method for the surface treatment with the surface treatment agent, a known method can be adopted, and either a dry surface treatment method or a wet surface treatment method may be used. Dry surface treatment is a method of dry mixing without using a large amount of solvent when mixing aluminum nitride filler before surface treatment with the surface treatment agent. Examples of dry surface treatment include a method of gasifying the surface treatment agent and mixing it with aluminum nitride filler before surface treatment, a method of spraying or dropping the liquid surface treatment agent and mixing it with aluminum nitride filler before surface treatment, and a method of diluting the surface treatment agent with a small amount of organic solvent to increase the amount of liquid, and then spraying or dropping it.

[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 the raw materials or intentionally added during the synthesis process, up to about 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 reduces 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, more preferably 0.1 to 1.0 μm, and even more preferably 0.15 to 0.8 μm, and 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) 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. Furthermore, the contact area of ​​the thermally conductive particles 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, more preferably 0.05 to 0.8, and even more preferably 0.10 to 0.7. 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 / g, more preferably 1.5 to 30m 2 / g, more preferably 2 to 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 embeddability.

[0084] The higher the crystallinity of the alumina filler (C), the better, 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 called 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. An 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, more preferably 0.05 to 0.9 μm, and even more preferably 0.08 to 0.7 μm. 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, more preferably 0.1 to 1.0 μm, and even more preferably 0.15 to 0.8 μm. 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, more preferably 0.2 to 1.5 μm, and even more preferably 0.3 to 1.2 μm.

[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 to 30 m / g. 2 / g, more preferably 2 to 20m 2 / g.

[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 agents as the silane coupling agent (SC1). From the viewpoint of embeddability and adhesion 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 of a secondary amine structure or a (meth)acrylic group, and even more preferably has an organic reactive group containing a (meth)acrylic group.

[0095] From the viewpoints of filler dispersibility, thermal conductivity of the cured product, and embeddability and adhesion 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 that 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) with 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 easily 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 between the alumina fillers (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. Therefore, the melt viscosity η of the resin composition film 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 does not adversely affect the 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 such that 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 resulting 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, if the alumina filler (C), which has 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 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 method or a wet surface treatment method. 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.

[0104] <Content of each ingredient> The resin composition film contains 700 to 1400 parts by mass, preferably 750 to 1300 parts by mass, and more preferably 800 to 1200 parts by mass of aluminum nitride filler (B) and alumina filler (C) in total, per 100 parts by mass of epoxy resin (A). 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 aluminum nitride filler (B) to the content of alumina filler (C) (content of aluminum nitride filler (B) / content of 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 to 2.5, more preferably 0.5 to 2.2. By keeping the value of S2 / S1 within this 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 fillers, 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). The alumina filler (C) may be one type or two or more types.

[0108] <Other ingredients> 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] The curing agent may be, for example, 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 it. 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, and examples of the epoxy resin curing agent 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, a phenol-based curing agent and naphthol-based curing agent having a novolac structure is preferred from the viewpoint of the heat resistance and water resistance of the cured product obtained from the resin composition film. Preferred phenolic curing agents having a novolac structure include phenol novolac, cresol novolac, bisphenol A novolac, phenol aralkyl novolac, biphenyl aralkyl novolac, aminotriazine novolac (triazine structure-containing phenol novolac), triphenylmethane novolac, and cyclopentadiene phenol novolac. 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 curing agent having a dicyclopentadiene structure is "HPC-8000-65T" manufactured by DIC Corporation. An example of a commercially available active ester 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, more preferably 65 to 150 parts by mass, and even more preferably 75 to 125 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 total number of reactive groups such as hydroxyl groups and active ester groups in the curing agent is preferably 0.5 to 2, more preferably 0.6 to 1.5, and even more preferably 0.65 to 1.25, relative to the total number of epoxy groups in the epoxy resin (A). The total number of epoxy groups in the epoxy resin (A) is the sum of 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 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. The epoxy resin curing accelerator has the function of accelerating the reaction between the epoxy groups of the epoxy resin (A) and the reactive groups of the curing agent, and 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 in the resin composition film, 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, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the epoxy resin (A).

[0118] As the epoxy resin curing accelerator, any known accelerator can be used without any 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-based 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-furan Examples of suitable epoxy resins 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 other resins 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. 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 resins may be used alone or in combination of two or more.

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

[0126] An example of a commercially available phenoxy resin containing a bisphenolacetophenone skeleton is "YX6954BH30" manufactured by Mitsubishi Chemical Corporation. An example of a commercially available phenoxy resin containing a bisphenol S skeleton is "YX8100BH30" manufactured by Mitsubishi Chemical Corporation. Further examples of commercially available phenoxy resins include "YX7553BH30" manufactured by Mitsubishi Chemical Corporation.

[0127] The weight-average molecular weight of the phenoxy resin is preferably 5000 to 10000. The weight-average molecular weight of the phenoxy resin is a weight-average molecular weight measured by gel permeation chromatography and converted into polystyrene. 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, more preferably 0.5 to 30 parts by mass, and even more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the epoxy resin (A).

[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, relative to 100 parts by mass of the total amount of the aluminum nitride filler (B) and the alumina filler (C). It is particularly preferable 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, and 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 type 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 of manufacturing resin composition film] The resin composition film can be produced, for example, by 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, and 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] In the varnish, gel components are generated in which the filler and the epoxy resin (A) are combined together. 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. This gel content cannot be removed by filtration using a filter with large openings. Furthermore, when the varnish is filtered using a filter with small openings, the gel content causes a gel-like filter cake to grow 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 cross-flow filtration, in which the slurry is made to flow at high speed parallel to the surface of the filter medium to sweep 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 forces; 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. Another example of cakeless filtration is a method in which shear force is applied parallel to the filter surface with a resin spatula or the like to perform filtration while breaking down the cake.

[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 for removing foreign matter, etc., and specifically, the mesh size is preferably 50 μm or less, and particularly preferably 30 μm or less. In filtration of varnish, it is also a preferred method to perform cakeless filtration after performing normal filtration for removing foreign matter and aggregates.

[0140] The cakeless filtered varnish can be formed into a film by a conventionally known method, and a suitable method among them is to coat the varnish on a support using a die coater, knife coater, comma coater, gravure coater, or the like, and then dry the organic solvent by heating, blowing hot air, or the like to produce a resin composition film. It is preferable to dry the varnish coated on the support so that the amount of solvent remaining in the resin composition film falls within the above range. Although it 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, the resin composition film can be obtained without excessive heat curing.

[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, so that the resin composition film can conform to the shape of a conductor layer when producing a multilayer printed wiring board or a component-embedded substrate. Further curing of the resin composition film can then be advanced to improve the strength and durability of the resin composition 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 viewpoint of wettability when coating the resin composition film and releasability when producing various semiconductor substrates, the coated surface of the plastic film serving as the support may be subjected to a release treatment, a matte treatment, a corona discharge treatment, or the like. The support may be a metal foil such as copper foil or aluminum foil. Suitable copper foils include rolled copper foil and electrolytic copper foil. By using a metal foil as the support, the step of laminating the metal foil can be omitted in the production of various substrates, and the adhesive strength between the support and the resin composition film can be improved. 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 conforming 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 be wound into a roll. When producing multilayer printed wiring boards, component-embedded substrates, and other semiconductor materials, the protective film is peeled off and used.

[0145] [Applications of resin composition films] 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 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. [Example]

[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 resin> 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 (Nippon Kayaku Co., Ltd., trisphenolmethane epoxy resin, epoxy equivalent 166, softening point 60°C) Liquid epoxy resin (A-2) jER828 (Mitsubishi Chemical Corporation, bisphenol A epoxy resin, epoxy equivalent 189, viscosity (25°C) 135 poise)

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

[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.The isopropyl alcohol was then 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.

[0150] <Alumina filler (C)> <Untreated alumina filler> AA-03F (Sumitomo Chemical Co., Ltd.) AHPA-0.5AF (manufactured by Sasol) NXA-150 (Sumitomo Chemical Co., Ltd.) AA-04 (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 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. The isopropyl alcohol was then 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 surface treatment.

[0153] <Silane coupling agent (SC1) and silane coupling agent (SC2)> N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., KBM-573) 3-Methacryloxypropyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., KBE-503) 3-Glycidoxypropyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., KBE-403) 3-Acryloxypropyltrimethoxysilane (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 (Nippon Kayaku Co., Ltd., biphenyl aralkylphenol novolac, hydroxyl equivalent 230, softening point 103°C)

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

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

[0157] [Evaluation of filler properties] The physical properties of the untreated alumina filler, the aluminum nitride filler (B) and the 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 dispersed by 200 W ultrasonic irradiation for 2 minutes. The particle size distribution of the sample was measured using a laser diffraction / scattering particle size analyzer (MICROTRACK-MT3300EXII, manufactured by Microtrack-Bell Corporation). Water was used as the dispersion medium for untreated alumina filler, while ethanol was used for surface-treated aluminum nitride filler and surface-treated alumina filler. The volume frequency distribution of the obtained particle size (particle size distribution) was calculated by accumulating the volume frequency from the smallest particle size to the smallest particle size. The particle size at 10% of the cumulative value was defined as the 10% particle size diameter (D10), the particle size at 50% of the cumulative value was defined as the average particle size (D50), the particle size at 90% of the cumulative value was defined as the 90% particle size diameter (D90), and the maximum particle size measured (particle size at 100% cumulative volume) was defined as the maximum particle size diameter (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 (single-point nitrogen adsorption 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] [Table 1]

[0161] [Table 2]

[0162] [Table 3]

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

[0164] The filtrate was then filtered using a mesh filter with 30 μm openings. When filtering using the 30 μm mesh filter, a gel-like filter cake formed on the filter, preventing the filtrate from passing through. Therefore, a shear force was applied parallel to the filter surface with a resin spatula or the like to break up the cake while filtering. A resin composition varnish was prepared using the above procedures.

[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, because 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 previously produced was measured by the method described below, and the drying temperature and drying time were appropriately adjusted 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 remaining solvent amount> The resin composition film laminated on the support was cut together with the support into a 10 cm square, and its mass A was measured. Next, the resin composition film cut into a 10 cm square 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 amount of remaining solvent was calculated by applying the measured masses A to C to the following formula. Residual solvent amount (%) = (AB) / (AC) 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 remaining solvent was changed by changing the drying temperature and drying time.

[0169] [Comparative Examples 1 to 3] A resin composition film was 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 laminates were pressure-bonded at 100°C to produce laminate (2). Thereafter, the support located on the surface of laminate (2) was peeled off, and 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 is calculated by the thermal diffusivity (m 2 / sec) x density (kg / m 3 ) × specific heat (J / kg·K). Thermal diffusivity was measured using a tabletop thermal diffusivity / thermal conductivity measuring device (NETZSCH, Xenon Flash Analyzer LFA467 HyperFlash) with the xenon flash method (laser flash method, ISO22007-4). Both sides of the cured material were gold coated and graphite sprayed, and thermal diffusivity measurements were performed with a charging voltage of 200 V and a pulse width of 20 μsec.

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

[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 had been formed (copper pattern residual copper ratio 75%, minimum pore size 120 μm), and after reducing the pressure at 40°C for 60 seconds using a vacuum heating press, the resin composition film was pressed at 0.7 MPa. The resin composition film was then 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", a 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] [Table 4]

[0182] [Table 5]

[0183] [Table 6]

Claims

1. An epoxy resin (A), an aluminum nitride filler (B), and an alumina filler (C), The epoxy resin (A) contains 700 to 1,400 parts by mass of the aluminum nitride filler (B) and the alumina filler (C) in total, relative to 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 residual solvent amount is 3.5% or less, The minimum melt viscosity temperature determined by dynamic viscoelasticity measurement with 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, 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％ is in the range of 300,000 to 2,000,000 poise, Resin composition film.

2. 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, The resin composition film according to claim 1, wherein the average particle diameter D50 of the alumina filler (C) is smaller than the average particle diameter D50 of the aluminum nitride filler (B).

3. 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, 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 of the silane coupling agent (SC1). The resin composition film according to claim 2.

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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