Resin composition, film having resin, prepreg, metal foil having resin, metal clad laminate and printed wiring board

Abstract

The resin composition contains an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D). The flow regulator (C) contains a polyether ester flow regulator (C1) that does not contain phosphorus atoms. The inorganic filler (D) contains at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. The content of the inorganic filler (D) is 84 mass% to 97 mass% with respect to the total mass of the resin composition. The inorganic filler (D) has at least two peaks in a particle size range of 0.05 [mu] m to 25 [mu] m in a volume-based particle size distribution measured by a laser diffraction / scattering method.

Description

Technical Field

[0001] The present disclosure generally relates to a resin composition, a film having a resin, a prepreg, a metal foil sheet having a resin, a metal-clad laminate, and a printed wiring board. More specifically, the present disclosure relates to a resin composition containing an epoxy resin, a film having a resin, a prepreg, a metal foil sheet having a resin, a metal-clad laminate, and a printed wiring board. Background Art

[0002] Patent Document 1 discloses an epoxy resin composition for a heat conductive material. The epoxy resin composition for a heat conductive material contains an epoxy resin, a curing agent or a curing accelerator, and an inorganic filler (heat conductive filler). The epoxy resin composition is characterized in that the epoxy resin has a benzophenanthrene skeleton.

[0003] In order to improve the thermal conductivity, the resin composition needs to contain a high concentration of filler. Nevertheless, as the concentration of the filler increases, the fluidity of the resin composition tends to decrease accordingly, thereby also creating a need to reduce the viscosity of the resin composition. However, if the viscosity of the resin composition is too low, the resin composition will flow very easily, making it difficult to control the thickness of the insulating layer made from the resin composition. Therefore, there is an increasing need to develop a technique for improving the thermal conductivity of the insulating layer while keeping its thickness as uniform as possible.

[0004] Citation List

[0005] Patent Document

[0006] Patent Document 1: JP 2017-008153 A Summary of the Invention

[0007] An object of the present disclosure is to provide a resin composition, a film having a resin, a prepreg, a metal foil sheet having a resin, a metal-clad laminate, and a printed wiring board that contribute to forming an insulating layer having high thermal conductivity and uniform thickness.

[0008] The resin composition according to one aspect of the present disclosure contains: an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D). The flow regulator (C) includes a polyether ester flow regulator (C1) that does not contain a phosphorus atom. The inorganic filler (D) includes at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. The content of the inorganic filler (D) is equal to or greater than 84% by mass and equal to or less than 97% by mass relative to the total mass of the resin composition. In the volume-based particle size distribution measured by laser diffraction and scattering method, the inorganic filler (D) has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm.

[0009] A film with a resin according to another aspect of the present disclosure includes: a resin layer containing the above resin composition or a semi-cured product of the resin composition; and a support film supporting the resin layer.

[0010] A prepreg according to another aspect of the present disclosure includes: a resin layer containing the above resin composition or a semi-cured product of the resin composition; and a fiber base member impregnated with the resin composition.

[0011] A metal foil sheet with a resin according to still another aspect of the present disclosure includes: a resin layer containing the above resin composition or a semi-cured product of the resin composition; and a metal foil sheet bonded to the resin layer.

[0012] A metal-clad laminate according to yet another aspect of the present disclosure includes: an insulating layer containing a cured product of the above resin composition; and a metal layer bonded to the insulating layer.

[0013] Another metal-clad laminate according to yet another aspect of the present disclosure includes: an insulating layer containing a cured product of the above prepreg; and a metal layer bonded to the insulating layer.

[0014] A printed circuit board according to yet another aspect of the present disclosure includes: an insulating layer containing a cured product of the above resin composition; and a conductor layer bonded to the insulating layer.

[0015] Another printed circuit board according to yet another aspect of the present disclosure includes: an insulating layer containing a cured product of the above prepreg; and a conductor layer bonded to the insulating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Figure 1 A of [] is a schematic cross-sectional view showing a film with a resin (and without a protective film) according to an exemplary embodiment of the present disclosure; and Figure 1 B of [] is a schematic cross-sectional view showing a film with a resin (and with a protective film) according to an exemplary embodiment of the present disclosure;

[0017] Figure 2 Figure 2 is a schematic cross-sectional view showing a prepreg according to an exemplary embodiment of the present disclosure;

[0018] Figure 3 Figure 3 is a schematic cross-sectional view showing a metal foil sheet with a resin according to an exemplary embodiment of the present disclosure;

[0019] Figure 4 Figure 4 ​​​​A of [description] is a schematic cross-sectional view showing a metal-clad laminate (without a fiber substrate) according to an exemplary embodiment of the present disclosure; and Figure 4 B of [description] is a schematic cross-sectional view showing a metal-clad laminate (with a fiber substrate) according to an exemplary embodiment of the present disclosure;

[0020] Figure 5 Figure 5 is a schematic cross-sectional view showing a printed circuit board according to an exemplary embodiment of the present disclosure;

[0021] Figure 6 Figure 6 A of [description] is a schematic cross-sectional view showing a test printed circuit board (not yet etched); and Figure 6 B of [description] is a schematic cross-sectional view showing a test printed circuit board (already etched);

[0022] Figure 7 Figure 7 A of [description] is a schematic plan view showing a test printed circuit board; and Figure 7 B of [description] is a schematic plan view showing a dummy pattern; and

[0023] Figure 8 Figure 8 is a schematic plan view indicating the positions for measuring the thickness of a test printed circuit board. Detailed Description

[0024] 1. Overview

[0025] Patent Document 1 teaches in paragraph

[0058] that if the content of the heat-conductive filler is less than 40% by mass, the epoxy resin composition for heat-conductive materials will not have sufficient thermal conductivity. On the other hand, Patent Document 1 also teaches that if the content of the heat-conductive filler is greater than 95% by mass, the epoxy resin composition for heat-conductive materials will have a very high viscosity, resulting in reduced coatability and processability.

[0026] It can be seen that in order to improve thermal conductivity, the resin composition needs to contain a high concentration of filler. Nevertheless, as the concentration of the filler increases, the fluidity of the resin composition tends to decrease accordingly, thereby also creating a need to reduce the viscosity of the resin composition.

[0027] ​​​​However, if the viscosity of the resin composition is too low, the resin composition will flow very easily, making it difficult to control the thickness of the insulating layer made from the resin composition. As the target uses of the epoxy resin composition for heat-conductive materials, Patent Document 1 lists a material for an interlayer dielectric film of a build-up substrate and a material for an adhesive film of a build-up substrate (see, for example, paragraph

[0022] of Patent Document 1). If a plurality of insulating layers each having a non-uniform thickness are laminated on top of each other, the layers with non-uniform thickness will be stacked layer by layer, possibly making the thickness of the multilayer printed wiring board significantly non-uniform.

[0028] Therefore, the present inventors conducted in-depth and meticulous research to improve the heat conductivity of the insulating layer while keeping its thickness as uniform as possible. As a result, the present inventors successfully developed a resin composition that helps to form an insulating layer with a uniform thickness while achieving high heat conductivity. Specifically, the resin composition according to the present embodiment contains an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D).

[0029] In the present embodiment, the flow regulator (C) includes a phosphorus atom-free polyether ester flow regulator (C1). The phosphorus atom-free polyether ester flow regulator (C1) mainly helps to make the thickness of the insulating layer 1 uniform.

[0030] On the other hand, the inorganic filler (D) includes at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. The content of the inorganic filler (D) is equal to or greater than 84% by mass and equal to or less than 97% by mass relative to the total mass of the resin composition. In the volume-based particle size distribution measured by laser diffraction and scattering method, the inorganic filler (D) has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm. The inorganic filler (D) mainly contributes to the heat conductivity of the insulating layer 1.

[0031] The present inventors found that if the resin composition contains the epoxy resin (A) and the phenolic resin (B) as described above, the phosphorus atom-free polyether ester flow regulator (C1) achieves particularly remarkable effects.

[0032] Therefore, the present embodiment helps to form an insulating layer with high heat conductivity and uniform thickness. The insulating layer 1 is a layer having electrical insulation properties and contains a cured product of the resin composition (refer to Figure 4 A to Figure 6 B).

[0033] 2. Detailed content

[0034] The resin composition according to the present embodiment will now be described. Thereafter, the film 2 having a resin, the prepreg 3, the metal foil sheet 4 having a resin, the metal-clad laminate 5, and the printed wiring board 6 according to the present embodiment will be described with reference to the drawings. All the drawings referred to in the following description of the embodiments are schematic views. Therefore, the ratios of the dimensions (including thicknesses) of the respective components shown in the drawings do not always reflect their actual dimensional ratios. It should be noted that the arrows indicating the respective directions in the drawings should not be construed as limiting the directions in which the film 2 having a resin and other embodiments of the present disclosure should be used, but are shown for ease of understanding of the following description and are all non-essential. It should also be noted that the X-axis, Y-axis, and Z-axis intersect at right angles to each other. In the following description, the phrase "when viewed in the XY plane" will be used when viewing something along the Z-axis.

[0035] (1) Resin composition

[0036] The resin composition according to the present embodiment contains an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D). Optionally, the resin composition may further contain other additional components. Examples of other additional components include, but are not limited to: catalysts, flame retardants, coupling agents, dispersants, metal deactivators, and ion scavengers. Each component will be described one by one in turn.

[0037] <Epoxy resin (A)>

[0038] The epoxy resin (A) has the property of curing when heated. Therefore, the epoxy resin (A) can impart thermosetting properties to the resin composition. The epoxy resin (A) is a compound having at least one epoxy group per molecule. Preferably, the epoxy resin (A) has more than two epoxy groups per molecule.

[0039] Examples of the epoxy resin (A) include, but are not limited to: triphenolmethane epoxy resin, naphthalene epoxy resin, biphenyl-arylalkyl epoxy resin, biphenyl epoxy resin, and dicyclopentadiene epoxy resin.

[0040] In particular, triphenolmethane epoxy resin is particularly preferred. The triphenolmethane epoxy resin has three epoxy groups each having a phenylmethane skeleton per molecule. It can be seen that the triphenolmethane epoxy resin has such a high functional group (epoxy group) density that the glass transition temperature (Tg) of the cured product of the resin composition is increased.

[0041] <Phenolic resin (B)>

[0042] The phenolic resin (B) is a prepolymer that can react with the epoxy resin (A). The phenolic resin (B) is a condensation reaction product of phenol and aldehyde.

[0043] Examples of the phenolic resin (B) include, but are not limited to: biphenyl-arylalkyl phenolic resins, phenyl-arylalkyl phenolic resins, novolak phenolic resins, cresol-novolak phenolic resins, bisphenol A novolak phenolic resins, naphthol phenolic resins, tetraphenol phenolic resins, and phosphorus-modified phenolic resins.

[0044] In particular, biphenyl-arylalkyl phenolic resins are particularly preferred. Biphenyl-arylalkyl phenolic resins can impart flame retardancy, heat resistance, and adhesiveness to the cured product of the resin composition.

[0045] The equivalent ratio of the phenolic resin (B) to the epoxy resin (A) is preferably equal to or greater than 0.7 and equal to or less than 1.3, and more preferably equal to or greater than 0.8 and equal to or less than 1.0. By setting the equivalent ratio to a value equal to or greater than 0.7, the possibility of causing a decrease in the glass transition temperature (Tg) is reduced, and thereby the possibility of insufficient curing of the resin composition is reduced. On the other hand, by setting the equivalent ratio to a value equal to or less than 1.3, an increase in polar groups such as hydroxyl groups is reduced, thereby reducing the possibility of leaving stains, for example, when drilling holes in the insulating layer 1.

[0046] <Flow regulator (C)>

[0047] The flow regulator (C) is a component that can adjust the degree of fluidity of the resin composition being molded. The flow regulator (C) includes a phosphorus atom-free polyether ester flow regulator (C1). In particular, the phosphorus atom-free polyether ester flow regulator (C1) is effectively applicable to a resin system containing a combination of the epoxy resin (A) and the phenolic resin (B). That is, even if such a resin system contains a high concentration of the inorganic filler (D), the phosphorus atom-free polyether ester flow regulator (C1) can impart appropriate fluidity to the resin composition being molded.

[0048] Preferably, the flow regulator (C) is a liquid at 25°C and is non-ionic. The flow regulator (C) in the liquid form at 25°C improves the flexibility of the film material (such as the film 2 having a resin, the prepreg 3, and the metal foil sheet 4 having a resin), and makes the film material less likely to break, thereby improving the handleability of the film material. In addition, the non-ionic flow regulator (C) does not ionize and has no charge, thereby ensuring the insulation reliability of the insulating layer 1.

[0049] Preferably, the phosphorus atom-free polyether ester flow modifier (C1) has a plurality of ether structures, a plurality of ester structures, and a plurality of carboxyl groups in a single molecule. Such a phosphorus atom-free polyether ester flow modifier (C1) can be prepared, for example, by reacting a polyol having two to six hydroxyl groups with a carboxyl group-introducing substance such that the molar ratio of the hydroxyl group to the carboxyl group-introducing substance is in the range of 3:1 to 1:1. The phosphorus atom-free polyether ester flow modifier (C1) prepared in this way can reduce the possibility that the viscosity of the resin composition excessively increases or decreases during molding of the resin composition. This can make the thickness of the insulating layer 1 even more uniform.

[0050] With respect to 100 parts by mass of the inorganic filler (D), the content of the flow modifier (C) is preferably equal to or greater than 0.005 part by mass and equal to or less than 0.5 part by mass, more preferably equal to or greater than 0.008 part by mass and equal to or less than 0.4 part by mass, and even more preferably equal to or greater than 0.01 part by mass and equal to or less than 0.3 part by mass. By setting the content of the flow modifier (C) to a value equal to or greater than 0.005 part by mass, the flow modifier (C) can exert a significant effect. On the other hand, by setting the content of the flow modifier (C) to a value greater than 0.5 part by mass, the effect achieved by the flow modifier (C) becomes saturated. This can make the thickness of the insulating layer 1 even more uniform.

[0051] <Inorganic filler (D)>

[0052] The inorganic filler (D) is an aggregate of particles having thermal conductivity. The inorganic filler (D) contains at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. This can improve the thermal conductivity of the insulating layer 1 as compared with the case where the inorganic filler (D) does not contain these fillers. Optionally, the inorganic filler (D) may further contain any other filler (hereinafter collectively referred to as "third inorganic filler (D3)") other than the magnesium oxide filler, the aluminum nitride filler, and the aluminum oxide filler. Examples of the third inorganic filler (D3) include, but are not limited to: molybdenum compound filler, silica filler, aluminum hydroxide filler, magnesium hydroxide filler, talc filler, clay filler, zinc oxide filler, boron nitride filler, and mica filler.

[0053] With respect to the total mass of the resin composition, the content of the inorganic filler (D) can be equal to or greater than 84% by mass and equal to or less than 97% by mass, preferably equal to or greater than 85% by mass and equal to or less than 96% by mass, and more preferably equal to or greater than 87% by mass and equal to or less than 94% by mass. Note that the content of the inorganic filler (D) is the total content of the magnesium oxide filler, the aluminum nitride filler, and the aluminum oxide filler.

[0054] By setting the content of the inorganic filler (D) to a value equal to or greater than 84% by mass, the thermal conductivity of the insulating layer 1 can be increased. On the other hand, by setting the content of the inorganic filler (D) to a value equal to or less than 97% by mass, the possibility of causing a decrease in the fluidity of the resin composition being molded or an excessive increase in its viscosity can be reduced.

[0055] In the volume-based particle size distribution (frequency distribution) measured by the laser diffraction and scattering method, the inorganic filler (D) preferably has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm. This enables the particles of the inorganic filler (D) to be closer to each other within the insulating layer 1.

[0056] In this case, the particle size distribution is measured by the laser diffraction and scattering method. The particle size distribution is represented as a frequency distribution or a cumulative size distribution (cumulative distribution). As used herein, the "cumulative size distribution" refers to the distribution of the cumulative upper size limit (cumulative undersize distribution).

[0057] The frequency distribution herein refers to the distribution represented by a graph in which the abscissa represents the particle size and the ordinate represents the (volume) percentage of the amount of particles of each particle size relative to the total amount of particles. The abscissa can also be represented on a logarithmic scale.

[0058] On the other hand, the cumulative size distribution (cumulative undersize distribution) herein refers to the distribution represented by a graph in which the abscissa represents the particle size and the ordinate represents the (volume-based) percentage of the amount of particles having a size equal to or less than a certain particle size relative to the total amount of particles. The abscissa can also be represented on a logarithmic scale.

[0059] The inorganic filler (D) preferably contains: a first inorganic filler (D1) and a second inorganic filler (D2) having an average particle size smaller than the average particle size of the first inorganic filler (D1). This enables the particles of the first inorganic filler (D1) to be in thermal contact with each other via the particles of the second inorganic filler (D2) in the insulating layer 1. This can further increase the thermal conductivity of the insulating layer 1. As used herein, the "average particle size" refers to the 50% size (D50 (median size)) in the above cumulative size distribution (cumulative undersize distribution).

[0060] The first inorganic filler (D1) preferably has an average particle size greater than 1 μm and equal to or less than 25 μm, and more preferably has an average particle size equal to or greater than 4 μm and equal to or less than 20 μm. On the other hand, the second inorganic filler (D2) preferably has an average particle size equal to or greater than 0.05 μm and equal to or less than 1 μm, and more preferably has an average particle size equal to or greater than 0.1 μm and equal to or less than 0.4 μm. This can further promote the thermal contact of the particles of the first inorganic filler (D1) in the insulating layer 1 via the particles of the second inorganic filler (D2). Therefore, this enables further improvement of the thermal conductivity of the insulating layer 1.

[0061] In the volume-based particle size distribution (frequency distribution) measured by the laser diffraction and scattering method, the inorganic filler (D) has at least one peak in the range of particle size greater than 1 μm and equal to or less than 25 μm, and has at least one peak in the range of particle size equal to or greater than 0.05 μm and equal to or less than 1 μm. This enables the particles of the inorganic filler (D) to be even closer to each other within the insulating layer 1. Therefore, this enables further improvement of the thermal conductivity of the insulating layer 1.

[0062] In the volume-based particle size distribution (cumulative size distribution) measured by the laser diffraction and scattering method, the cumulative proportion of particles each having a particle size greater than 1 μm and equal to or less than 70 μm is equal to or greater than 40% by volume and equal to or less than 80% by volume, and the cumulative proportion of particles each having a particle size equal to or greater than 0.05 μm and equal to or less than 1 μm is equal to or greater than 20% by volume and equal to or less than 60% by volume. This enables the particles of the inorganic filler (D) to be even closer to each other within the insulating layer 1. Therefore, this enables further improvement of the thermal conductivity of the insulating layer 1.

[0063] <Other additional components>

[0064] Examples of the catalyst include, but are not limited to, imidazole compounds such as 2-ethyl-4-methylimidazole. By adding the catalyst to the resin composition, the curing reaction of the resin composition being molded can be promoted.

[0065] Examples of the flame retardant include, but are not limited to: phosphorus-based flame retardants, halogen-based flame retardants, and inorganic flame retardants. By adding the flame retardant to the resin composition, the insulating layer 1 can be made flame retardant. Phosphorus-based flame retardants are preferred because phosphorus-based flame retardants are halogen-free.

[0066] Examples of the coupling agent include, but are not limited to, silane coupling agents such as 8-glycidoxy octyl trimethoxysilane. By adding the coupling agent to the resin composition, the degree of adhesion between the insulating layer 1 and the metal layer 51 can be improved (refer to Figure 4 of A andFigure 4 the degree of adhesion between B) and the insulating layer 1 and the conductor layer 70 (refer to Figure 5 and 6 ).

[0067] Examples of the dispersant include, but are not limited to, wetting dispersants. By adding the dispersant to the resin composition, the inorganic filler (D) can be uniformly dispersed in the insulating layer 1.

[0068] Examples of the metal deactivator include, but are not limited to: hydrazide derivatives, oxalic acid derivatives, and salicylic acid derivatives. By adding the metal deactivator to the resin composition, the metal deactivator forms a complex with the active metal ions (such as copper ions) that promote oxidative degradation. This can reduce the degradation of the insulating layer 1.

[0069] Examples of the ion scavenger include, but are not limited to, hydrotalcite. By adding the ion scavenger to the resin composition, the ion scavenger can capture ionic impurities. This reduces ion migration. Therefore, this ensures the insulation reliability of the insulating layer 1.

[0070] (2) Film having a resin

[0071] As Figure 1 shown in A of, the film 2 having a resin according to the present embodiment is in the form of a film having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The film 2 having a resin includes a resin layer 20 and a support film 21. As Figure 1 shown in B of, the film 2 having a resin may further include a protective film 22. The film 2 having a resin can be used as a material for the build-up process.

[0072] <Resin layer>

[0073] The resin layer 20 is in the form of a film having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The resin layer 20 contains the above resin composition or a semi-cured product of the resin composition. The semi-cured product of the resin composition herein refers to the resin composition in the intermediate stage (stage B) of the curing reaction. When heated, the resin layer 20 cures and becomes the insulating layer 1. For example, the thickness of the resin layer 20 can be, but is not limited to, equal to or greater than 50 μm and equal to or less than 200 μm.

[0074] <Support film>

[0075] The support film 21 is attached to one surface of the resin layer 20 (for example, in Figure 1 A of and Figure 1(the surface of B facing the negative side of the Z-axis). In this way, the resin layer 20 is supported by the support film 21. By supporting the resin layer 20 with the support film 21 in this way, the resin layer 20 is easier to handle. Optionally, the support film 21 can be peeled off from the resin layer 20 as needed.

[0076] Examples of the support film 21 include, but are not limited to: polyethylene terephthalate (PET) film, polyimide film, polyester film, polyoxalylurea film, polyetheretherketone film, polyphenylene sulfide film, polyaramide film, polycarbonate film, and polyacrylate film.

[0077] <Protective film>

[0078] The protective film 22 is attached to the other surface of the resin layer 20 (for example, on Figure 1 the surface of B facing the positive side of the Z-axis). In this way, the protective film 22 protects the resin layer 20. By protecting the resin layer 20 with the protective film 22, the possibility of foreign particles depositing on the resin layer 20 is reduced. Optionally, the protective film 22 and the support film 21 can be peeled off from the resin layer 20 as needed.

[0079] Examples of the protective film 22 include, but are not limited to: polyethylene terephthalate (PET) film, polyolefin film, polyester film, and polymethylpentene film.

[0080] (3) Prepreg

[0081] As Figure 2 shown, the prepreg 3 according to this embodiment is in the form of a sheet having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The prepreg 3 includes a resin layer 30 and a fiber substrate 31. For example, like the film 2 having resin, the prepreg 3 can be used as a material for the lamination method. For example, the thickness of the prepreg 3 can be, but is not limited to, equal to or greater than 60 μm and equal to or less than 200 μm.

[0082] <Resin layer>

[0083] The resin layer 30 contains the above resin composition or a semi-cured product of the resin composition. The resin composition is impregnated into the fiber substrate 31. When heated, the resin layer 30 cures to become the insulating layer 1.

[0084] <Fiber substrate>

[0085] The fiber substrate 31 serves as a reinforcing member. The fiber substrate 31 is impregnated with the resin composition.

[0086] The fiber base material 31 may be a piece of textile fabric or a piece of non-woven fabric. Examples of the fiber base material 31 include, but are not limited to: glass cloth, aramid cloth, polyester cloth, glass non-woven fabric, aramid non-woven fabric, polyester non-woven fabric, pulp paper, and linterpaper. The type of glass cloth is preferably #7628, #1501, #2116, #1080, #1078, and #106.

[0087] (4) Metal foil sheet with resin

[0088] As Figure 3 shown, the metal foil sheet 4 with resin according to the present embodiment is in the form of a sheet having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The metal foil sheet 4 with resin includes a resin layer 40 and a metal foil sheet 41. For example, like the resin film 2 and the prepreg 3, the metal foil sheet 4 with resin can also be used as a material for the lamination method.

[0089] <Resin layer>

[0090] The resin layer 40 contains the above resin composition or a semi-cured product of the resin composition. When heated, the resin layer 40 cures and becomes the insulating layer 1. The thickness of the resin layer 40 can be, but is not limited to, equal to or greater than 60 μm and equal to or less than 200 μm.

[0091] <Metal foil sheet>

[0092] The metal foil sheet 41 is combined with the resin layer 40. In Figure 3 it, the metal foil sheet 41 is combined with one surface of the resin layer 40 (i.e., the surface facing the negative side of the Z-axis). For example, during the manufacturing process of the printed circuit board 6, the metal foil sheet 41 has its excess part removed by etching, thereby becoming the conductor layer 70.

[0093] Examples of the metal foil sheet 41 include, but are not limited to: copper foil sheet (including electrolytic copper foil sheet and rolled copper foil sheet), stainless steel foil sheet, nickel foil sheet, and nickel-chromium alloy foil sheet. For example, the thickness of the metal foil sheet 41 can be, but is not limited to, equal to or greater than 5 μm and equal to or less than 35 μm.

[0094] (5) Metal-clad laminate

[0095] As Figure 4 of A and Figure 4 of B shown, the metal-clad laminate 5 according to the present embodiment is in the form of a plate having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The metal-clad laminate 5 includes an insulating layer 1 and at least one metal layer 51. Although in Figure 4 of A the insulating layer 1 does not include the fiber base material 31, but as Figure 4As shown in B of , the insulating layer 1 may include a fibrous substrate 31. Figure 4 of A and Figure 4 The metal-clad laminate 5 shown in B of is a double-sided metal-clad laminate. Alternatively, the metal-clad laminate 5 may also be a single-sided metal-clad laminate. The metal-clad laminate 5 can be used to manufacture a printed wiring board 6 (including a core material).

[0096] <Insulating layer>

[0097] The insulating layer 1 is a layer having electrical insulation properties. The insulating layer 1 contains a cured product of the above resin composition or a cured product of the above prepreg 3. The insulating layer 1 may include a plurality of fibrous substrates 31. If the insulating layer 1 includes a plurality of fibrous substrates 31, the plurality of fibrous substrates 31 are arranged one on top of the other in the thickness direction (i.e., the Z-axis direction). For example, the thickness of the insulating layer 1 may be, but is not limited to, equal to or greater than 50 μm and equal to or less than 200 μm.

[0098] <Metal layer>

[0099] The metal layer 51 can be formed as a metal foil sheet 41, a plating layer, or a vapor deposition layer, and any of these methods is suitable. The metal material for the metal layer 51 is not limited to any specific metal material, but can be, for example, the same as the metal material for the metal foil sheet 41. The metal layer 51 is combined with the insulating layer 1. In Figure 4 of A and Figure 4 of B, the metal layer 51 includes a first metal layer 511 and a second metal layer 512. The first metal layer 511 is combined with one surface of the insulating layer 1 (i.e., the surface facing the positive side of the Z-axis), while the second metal layer 512 is combined with the other surface of the insulating layer 1 (i.e., the surface facing the negative side of the Z-axis). The first metal layer 511 or the second metal layer 512 can be omitted. For example, the thickness of the metal layer 51 may be, but is not limited to, equal to or greater than 18 μm and equal to or less than 210 μm.

[0100] (6) Printed wiring board

[0101] As Figure 5 shown, the printed wiring board 6 according to this embodiment is in the form of a plate having a certain thickness in the Z-axis direction and extending in the X-axis and Y-axis directions. The printed wiring board 6 includes an insulating layer 1 and at least one conductor layer 70. Although in Figure 5 the insulating layer 1 includes a fibrous substrate 31, the insulating layer 1 may not include a fibrous substrate 31. In Figure 5 only one insulating layer 1 is provided. Alternatively, two or more insulating layers 1 can be provided. In Figure 5In this case, two conductor layers 70 are provided. Alternatively, only one conductor layer 70 may be provided, or three or more conductor layers 70 may be provided. It can be seen that the "printed circuit board 6" as used herein also encompasses a multilayer printed circuit board (i.e., a printed circuit board having three or more conductor layers 70). Note that the printed circuit board 6 as used herein also encompasses Figure 6 A of Figure 6 and the test printed circuit board 60 shown in B of Figure 6 The test printed circuit board 60 in B of

[0102] <Insulating layer>

[0103] The insulating layer 1 contains a cured product of the above resin composition or a cured product of the above prepreg 3. A single insulating layer 1 may include a plurality of fiber substrates 31. If a single insulating layer 1 includes a plurality of fiber substrates 31, the plurality of fiber substrates 31 are arranged one on top of the other in the thickness direction (i.e., the Z-axis direction). For example, the thickness of the insulating layer 1 may be, but is not limited to, equal to or greater than 50 μm and equal to or less than 1600 μm.

[0104] <Conductor layer>

[0105] The conductor layer 70 includes: a signal layer for transmitting an electrical signal; a power supply layer for supplying power; and a ground layer for setting a ground potential. The conductor layer 70 is bonded to the insulating layer 1. The conductor layer 70 can be an outer layer or an inner layer, and either way is suitable. That is, Figure 5 the conductor layer 70 shown in Figure 6 A of Figure 6 is provided on the outside of the printed circuit board 6 and is therefore an outer layer. On the other hand, Figure 6 A of Figure 6 and the conductor layer 70 shown in B of Figure 6 A of Figure 6 is provided on the inside of the test printed circuit board 60 and is therefore an inner layer. The thickness of the conductor layer 70 may be, but is not limited to, equal to or greater than 12 μm and equal to or less than 210 μm. For example, the conductor width L of the conductor layer 70 (refer to

[0106] <Advantages>

[0107] In the present embodiment, the insulating layer 1 is a cured product of the above resin composition. The resin composition contains an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D).

[0108] In the present embodiment, the flow regulator (C) includes a phosphorus atom-free polyether ester flow regulator (C1). The phosphorus atom-free polyether ester flow regulator (C1) mainly contributes to making the thickness of the insulating layer 1 uniform.

[0109] On the other hand, the inorganic filler (D) includes at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. The content of the inorganic filler (D) is equal to or greater than 84% by mass and equal to or less than 97% by mass with respect to the total mass of the resin composition. In the volume-based particle size distribution measured by the laser diffraction and scattering method, the inorganic filler (D) has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm. The inorganic filler (D) mainly contributes to the thermal conductivity of the insulating layer 1.

[0110] As described above, if the resin composition contains the epoxy resin (A) and the phenolic resin (B), the phosphorus atom-free polyether ester flow regulator (C1) achieves a particularly remarkable effect. That is, even if the resin composition contains a high concentration of the inorganic filler (D), but is a resin system containing a combination of the epoxy resin (A) and the phenolic resin (B), the phosphorus atom-free polyether ester flow regulator (C1) can ensure appropriate fluidity.

[0111] Therefore, the present embodiment enables the formation of the insulating layer 1 having high thermal conductivity and uniform thickness.

[0112] 3. Aspect

[0113] From the description of the foregoing exemplary embodiments, it can be seen that the present disclosure has the following aspects. In the following description, for the purpose of clarifying the correspondence between the following aspects of the present disclosure and the above exemplary embodiments only, reference numerals in parentheses are added to each component.

[0114] The first aspect is a resin composition. The resin composition contains an epoxy resin (A), a phenolic resin (B), a flow regulator (C), and an inorganic filler (D). The flow regulator (C) includes a polyether ester flow regulator (C1) that does not contain a phosphorus atom. The inorganic filler (D) includes at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler. With respect to the total mass of the resin composition, the content of the inorganic filler (D) is equal to or greater than 84% by mass and equal to or less than 97% by mass. In the volume-based particle size distribution measured by the laser diffraction and scattering method, the inorganic filler (D) has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm.

[0115] This aspect enables the formation of an insulating layer (1) having high thermal conductivity and a uniform thickness.

[0116] The second aspect is a resin composition that can be implemented in combination with the first aspect. In the second aspect, the inorganic filler (D) includes: a first inorganic filler (D1); and a second inorganic filler (D2) having an average particle size smaller than the average particle size of the first inorganic filler (D1).

[0117] This aspect enables the further improvement of the thermal conductivity of the insulating layer (1).

[0118] The third aspect is a resin composition that can be implemented in combination with the second aspect. In the third aspect, the average particle size of the first inorganic filler (D1) is greater than 1 μm and equal to or less than 25 μm, and the average particle size of the second inorganic filler (D2) is equal to or greater than 0.05 μm and equal to or less than 1 μm.

[0119] This aspect enables the further improvement of the thermal conductivity of the insulating layer (1).

[0120] The fourth aspect is a resin composition that can be implemented in combination with any one of the first to third aspects. In the fourth aspect, in the volume-based particle size distribution measured by the laser diffraction and scattering method, the inorganic filler (D) has at least one peak in the range where the particle size is greater than 1 μm and equal to or less than 25 μm, and has at least one peak in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 1 μm.

[0121] This aspect enables the further improvement of the thermal conductivity of the insulating layer (1).

[0122] The fifth aspect is a resin composition that can be implemented in combination with any one of the first to fourth aspects. In the fifth aspect, in the volume-based particle size distribution measured by the laser diffraction and scattering method, the cumulative proportion of particles each having a particle size greater than 1 μm and equal to or less than 70 μm is equal to or greater than 40% by volume and equal to or less than 80% by volume, and the cumulative proportion of particles each having a particle size equal to or greater than 0.05 μm and equal to or less than 1 μm is equal to or greater than 20% by volume and equal to or less than 60% by volume.

[0123] This aspect enables further improvement of the thermal conductivity of the insulating layer (1).

[0124] The sixth aspect is a resin composition that can be implemented in combination with any one of the first to fifth aspects. In the sixth aspect, the flow modifier (C) is a liquid at 25°C and is non-ionic.

[0125] According to this aspect, the flow modifier (C) in the liquid form at 25°C improves the flexibility of the film material and makes the film material less likely to break, thereby improving the processability of the film material. In addition, the non-ionic flow modifier (C) does not ionize and has no charge, thereby ensuring the insulation reliability of the insulating layer (1).

[0126] The seventh aspect is a resin composition that can be implemented in combination with any one of the first to sixth aspects. In the seventh aspect, the phosphorus atom-free polyether ester flow modifier (C1) has a plurality of ether structures, a plurality of ester structures, and a plurality of carboxyl groups in a single molecule.

[0127] This aspect can make the thickness of the insulating layer (1) even more uniform.

[0128] The eighth aspect is a resin composition that can be implemented in combination with any one of the first to seventh aspects. In the eighth aspect, the content of the flow modifier (C) is equal to or greater than 0.005 parts by mass and equal to or less than 0.5 parts by mass with respect to 100 parts by mass of the inorganic filler (D).

[0129] This aspect can make the thickness of the insulating layer (1) even more uniform.

[0130] The ninth aspect is a film (2) having a resin. The film (2) having a resin includes: a resin layer (20) containing the resin composition according to any one of the first to eighth aspects or a semi-cured product of the resin composition; and a support film (21) supporting the resin layer (20).

[0131] This aspect enables the formation of an insulating layer (1) having high thermal conductivity and uniform thickness.

[0132] The tenth aspect is a prepreg (3). The prepreg (3) includes: a resin layer (30) containing the resin composition according to any one of the first to eighth aspects or a semi-cured product of the resin composition; and a fiber substrate (31) impregnated with the resin composition.

[0133] This aspect enables the formation of an insulating layer (1) having high thermal conductivity and a uniform thickness.

[0134] The eleventh aspect is a metal foil sheet (4) with a resin. The metal foil sheet (4) with a resin includes: a resin layer (40) containing the resin composition according to any one of the first to eighth aspects or a semi-cured product of the resin composition; and a metal foil sheet (41) bonded to the resin layer (40).

[0135] This aspect enables the formation of an insulating layer (1) having high thermal conductivity and a uniform thickness.

[0136] The twelfth aspect is a metal-clad laminate (5). The metal-clad laminate (5) includes: an insulating layer (1) containing a cured product of the resin composition according to any one of the first to eighth aspects; and a metal layer (51) bonded to the insulating layer (1).

[0137] This aspect enables the insulating layer (1) to have high thermal conductivity and a uniform thickness.

[0138] The thirteenth aspect is another metal-clad laminate (5). The metal-clad laminate (5) includes: an insulating layer (1) containing a cured product of the prepreg (3) according to the tenth aspect; and a metal layer (51) bonded to the insulating layer (1).

[0139] This aspect enables the insulating layer (1) to have high thermal conductivity and a uniform thickness.

[0140] The fourteenth aspect is a printed circuit board (6). The printed circuit board (6) includes: an insulating layer (1) containing a cured product of the resin composition according to any one of the first to eighth aspects; and a conductor layer (70) bonded to the insulating layer (1).

[0141] This aspect enables the insulating layer (1) to have high thermal conductivity and a uniform thickness.

[0142] The fifteenth aspect is another printed circuit board (6). The printed circuit board (6) includes: an insulating layer (1) containing a cured product of the prepreg (3) according to the tenth aspect; and a conductor layer (70) bonded to the insulating layer (1).

[0143] This aspect enables the insulating layer (1) to have high thermal conductivity and a uniform thickness.

[0144] Examples

[0145] Next, specific examples of the present disclosure will be described. Note that the examples described below are merely examples of the present disclosure and should not be construed as restrictive.

[0146] 1. Examples and Comparative Examples

[0147] (1) Materials

[0148] The following materials were used to prepare resin compositions according to the corresponding examples and comparative examples:

[0149] <Epoxy resin (A)>

[0150] · Epoxy resin 1: Triphenolmethane epoxy resin, product name "EPPN502H", produced by Nippon Kayaku Co., Ltd., epoxy equivalent of 158 to 178 g / eq; and

[0151] · Epoxy resin 2: Triphenolmethane epoxy resin, product name "HP-7250", produced by DIC Corporation, epoxy equivalent of 150 to 180 g / eq.

[0152] <Phenolic resin (B)>

[0153] · Biphenyl-arylalkyl phenolic resin, product name "MEHC-7403H", produced by UBE Corporation, hydroxyl equivalent of 132 g / eq.

[0154] <Flow modifier (C)>

[0155] <<Phosphorus atom-free polyether ester flow modifier (C1)>>

[0156] · Polyether ester type 1: Product name "Disparlon 3350EF", produced by Kusumoto Chemicals, Ltd.;

[0157] · Polyether ester type 2: Product name "Disparlon 3600N", produced by Kusumoto Chemicals, Ltd.; and

[0158] · Polyether ester type 3: Product name "Disparlon 3800", produced by Kusumoto Chemicals, Ltd.

[0159] <<Other flow modifiers (C)>>

[0160] · Polyamide type: Product name "Disparlon 3900EF", manufactured by Kusumoto Chemicals, Ltd.; and

[0161] · Polyether phosphate type: Product name "Disparlon 3500", manufactured by Kusumoto Chemicals, Ltd.

[0162] <Inorganic filler (D)>

[0163] <<First inorganic filler (D1)>>

[0164] · Alumina filler 1: Product name "AZ10-20", manufactured by NIPPON STEEL Chemical & Material Co., Ltd.;

[0165] · Magnesium oxide filler: Product name "RF-10CS", manufactured by Ube Material Industries, Ltd.;

[0166] · Aluminum nitride filler: Product name "HF-10c", manufactured by Tokuyama Corporation; and

[0167] · Calcium carbonate filler: Product name "MS-PS", manufactured by Konoshima Chemical Co., Ltd.

[0168] <<Second inorganic filler (D2)>>

[0169] · Alumina filler 2: Product name "AO-502", manufactured by ADMATECHS, specific surface area is 6.5 to 9.0 m 2 / g).

[0170] <<Third inorganic filler (D3)>>

[0171] · Molybdenum compound filler, product name "KG-501", manufactured by J. M. Huber Corporation.

[0172] <Others>

[0173] <<Curing agent>>

[0174] · Dicyandiamide (Dicy).

[0175] <<Catalyst>>

[0176] · 2-Ethyl-4-methylimidazole, product name "2E4MZ", manufactured by Shikoku Chemicals Corporation.

[0177] <<Flame retardant>>

[0178] · Phosphazene-based flame retardant (halogen-free flame retardant), product name "FP-100", produced by FUSHIMI Pharmaceutical Co., Ltd.

[0179] <<Coupling agent>>

[0180] · Silane coupling agent (8-glycidyloxyoctyltrimethoxysilane), product name "KBM-4803", produced by Shin-Etsu Chemical Co., Ltd.

[0181] <<Dispersant>>

[0182] · Wetting dispersant, product name "BYK-W903", produced by BYK-Chemie.

[0183] <<Metal deactivator>>

[0184] · Hydrazide-based, product name "CDA-10", produced by ADEKA Corporation.

[0185] <<Ion scavenger>>

[0186] · Hydrotalcite-based inorganic ion scavenger, product name "IXEPLAS-A1", produced by Toagosei Co., Ltd.

[0187] (2) Resin composition

[0188] The resin compositions according to the corresponding examples and comparative examples are produced by mixing the corresponding materials in the proportions shown in Tables 1 and 2 below (where the unit is parts by mass):

[0189] [Table 1]

[0190]

[0191] Table 2

[0192]

[0193] The D50 (50% particle size in the cumulative size distribution) and D99 (99% particle size in the cumulative size distribution) of the first inorganic filler (D1) and the second inorganic filler (D2) are shown in Table 3 below:

[0194] [Table 3]

[0195] (Unit: μm)

[0196]

[0197] (3) Film with resin

[0198] Mix the above materials together to prepare a mixture (compound) having the chemical compositions shown in Tables 1 and 2. Dissolve or disperse each of those mixtures in methyl ethyl ketone as a solvent, and stir in a planetary mixer, thereby preparing a varnish containing a resin composition corresponding to each one of the respective examples and comparative examples. Coat the varnish onto a support film, and then dry at 150 °C for 2 to 5 minutes, thereby manufacturing a film with resin (including a resin layer having a thickness of 150 μm and dimensions of 255 mm × 340 mm) according to each of the examples and comparative examples.

[0199] (4) Test printed circuit board

[0200] Provide a double-sided copper-clad laminate (a highly fire-resistant halogen-free multi-layer substrate material, product name "R-1566S", manufactured by Panasonic Corporation, having a thickness of 400 μm, and the copper foil having a thickness of 105 μm and dimensions of 255 mm × 340 mm). Perform an etching process on the copper foil sheets on both sides of the double-sided copper-clad laminate, thereby forming a conductor layer (virtual pattern) with a residual copper rate of 80% and obtaining a core member. Figure 7 A of shows the conductor layer (virtual pattern) of the core member when viewed in the XY plane. This virtual pattern is composed of a plurality of pattern elements 9. Figure 7 B of shows a single pattern element 9 when viewed in the XY plane. The virtual pattern includes four pattern elements in the X-axis direction multiplied by six pattern elements in the Y-axis direction (i.e., a total of twenty-four pattern elements).

[0201] Next, laminate a surface-treated electrolytic copper foil sheet (product name "CF-T8G-UN-18", manufactured by Fukuda Metal Foil & Powder Co., Ltd., having a nominal thickness of 18 μm and dimensions of 550 mm × 700 mm) on each surface of the core member via the resin layer of the film with resin (the support film has been peeled off), and heat and press under conditions including a temperature of 200 °C, a pressure of 3 MPa, and a duration of 60 minutes, thereby manufacturing a test printed circuit board 60 (refer to Figure 6 A of). After that, remove the copper foil sheets from both sides of the test printed circuit board 60 by etching.

[0202] 2. Evaluation

[0203] (1) Thermal conductivity

[0204] An insulating layer is obtained by heating and thereby curing the resin layer of a film having a resin. The thermal conductivity of the insulating layer is measured by the laser flash method defined in JIS R 1611 standard. The results are shown in Tables 4 and 5 below.

[0205] (2) Thickness of the insulating layer

[0206] For the test printed wiring board 60, the thickness of its insulating layer is measured. The corresponding positions (a total of twelve positions, namely M1–M6 and E1–E6) for measuring the thickness of the test printed wiring board when viewed in the XY plane are shown in Figure 8 . Specifically, the corresponding thicknesses in the Z-axis direction are measured with a micrometer at six positions M1–M6 in the central region of the test printed wiring board 60 and six positions E1–E6 at the ends of the test printed wiring board 60. Then, the thickness of the insulating layer at each of these twelve positions is calculated (by Figure 6 (T60–T13–T71–T72) / 2 in B of

[0207] [Table 4]

[0208]

[0209] [Table 5]

[0210]

[0211] List of reference numerals

[0212] 1 Insulating layer

[0213] 2 Film having a resin

[0214] 20 Resin layer

[0215] 21 Support film

[0216] 3 Prepreg

[0217] 30 Resin layer

[0218] 31 Fiber base material

[0219] 4 Metal foil sheet having a resin

[0220] 40 Resin layer

[0221] 41 Metal foil sheet

[0222] 5 Metal-clad laminate

[0223] 51 Metal layer

[0224] 6 Printed wiring board

[0225] 70 conductor layers

Claims

1. A resin composition, the resin composition containing: an epoxy resin (A), a phenolic resin (B), a flow modifier (C), and an inorganic filler (D), The flow modifier (C) includes a polyether ester flow modifier (C1) that does not contain a phosphorus atom, The inorganic filler (D) includes at least one filler selected from the group consisting of a magnesium oxide filler, an aluminum nitride filler, and an aluminum oxide filler, Relative to the total mass of the resin composition, the content of the inorganic filler (D) is equal to or greater than 84% by mass and equal to or less than 97% by mass, and In the volume-based particle size distribution measured by the laser diffraction and scattering method, the inorganic filler (D) has at least two peaks in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 25 μm.

2. The resin composition according to claim 1, wherein The inorganic filler (D) includes: a first inorganic filler (D1); and a second inorganic filler (D2) having an average particle size smaller than the average particle size of the first inorganic filler (D1).

3. The resin composition according to claim 2, wherein The average particle size of the first inorganic filler (D1) is greater than 1 μm and equal to or less than 25 μm, and The average particle size of the second inorganic filler (D2) is equal to or greater than 0.05 μm and equal to or less than 1 μm.

4. The resin composition according to claim 1, wherein In the volume-based particle size distribution measured by the laser diffraction and scattering method, the inorganic filler (D) has at least one peak in the range where the particle size is greater than 1 μm and equal to or less than 25 μm, and has at least one peak in the range where the particle size is equal to or greater than 0.05 μm and equal to or less than 1 μm.

5. The resin composition according to claim 1, wherein In the volume-based particle size distribution measured by the laser diffraction and scattering method, the cumulative proportion of particles each having a particle size greater than 1 μm and equal to or less than 70 μm is equal to or greater than 40% by volume and equal to or less than 80% by volume, and the cumulative proportion of particles each having a particle size equal to or greater than 0.05 μm and equal to or less than 1 μm is equal to or greater than 20% by volume and equal to or less than 60% by volume.

6. The resin composition according to claim 1, wherein The flow modifier (C) is a liquid at 25°C and is non-ionic.

7. The resin composition according to claim 1, wherein The polyether ester flow modifier (C1) that does not contain a phosphorus atom has a plurality of ether structures, a plurality of ester structures, and a plurality of carboxyl groups in a single molecule.

8. The resin composition according to claim 1, wherein Relative to 100 parts by mass of the inorganic filler (D), the content of the flow modifier (C) is equal to or greater than 0.005 part by mass and equal to or less than 0.5 part by mass.

9. A resin-containing film, the resin-containing film including: A resin layer containing the resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition; And A support film that supports the resin layer.

10. A prepreg, the prepreg comprising: A resin layer comprising the resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition; and A fiber substrate impregnated with the resin composition.

11. A metal foil sheet having a resin, the metal foil sheet having a resin comprising: A resin layer comprising the resin composition according to any one of claims 1 to 8 or a semi-cured product of the resin composition; and A metal foil sheet bonded to the resin layer.

12. A metal-clad laminate, the metal-clad laminate comprising: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 8; and A metal layer bonded to the insulating layer.

13. A metal-clad laminate, the metal-clad laminate comprising: An insulating layer comprising a cured product of the prepreg according to claim 10; and A metal layer bonded to the insulating layer.

14. A printed circuit board, the printed circuit board comprising: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 8; and A conductor layer bonded to the insulating layer.

15. A printed circuit board, the printed circuit board comprising: An insulating layer comprising a cured product of the prepreg according to claim 10; and A conductor layer bonded to the insulating layer.

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