Magnetic composition

Abstract

The present invention provides a magnetic composition capable of obtaining a cured product with improved relative magnetic permeability and reduced magnetic loss, and a magnetic sheet, a circuit substrate, and an inductor substrate obtained using the magnetic composition. The present invention is a magnetic composition comprising (A) a magnetic powder and (B) a binder resin, wherein the 10% particle size (D 10 ) in the particle size distribution of the (A) component is 1.7 μm or more and 2.6 μm or less, the 50% particle size (D 50 ) is 3.6 μm or more and 12.0 μm or less, and the 90% particle size (D 90 ) is 25.0 μm or more and 51.0 μm or less.

Description

Technical Field

[0001] This invention relates to magnetic compositions, and magnetic sheets, circuit boards, and sensor boards obtained using magnetic compositions. Background Technology

[0002] On circuit boards such as printed wiring boards, magnetic layers containing magnetic powder, such as sensor components, are sometimes provided. As the magnetic powder contained in the magnetic layer, in order to suppress the reduction of magnetic loss, for example, Patent Document 1 describes a silicon oxide coated soft magnetic powder for which a soft magnetic powder has undergone surface treatment with silicon oxide.

[0003] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2019-143241. Summary of the Invention

[0004] The technical problem that the invention aims to solve In recent years, in order to further improve the performance of sensor components, there has been a demand for technologies that can form magnetic layers with low magnetic losses. Therefore, the inventors have studied the relative permeability and magnetic loss of magnetic layers and found that if the relative permeability is increased, the magnetic loss increases, and if the magnetic loss is reduced, the relative permeability decreases. There is a trade-off between increasing the relative permeability and reducing the magnetic loss.

[0005] The present invention was made in view of the above circumstances, and its object is to provide a magnetic composition that can produce a solidified material with increased relative permeability and reduced magnetic loss, and a magnetic sheet, circuit board, and sensor board obtained using the magnetic composition.

[0006] Technical solutions adopted to solve technical problems Through diligent research, the inventors discovered that by including magnetic powder with a specified particle size distribution in the magnetic composition, the trade-off between relative permeability and magnetic loss can be resolved, thus completing this invention.

[0007] That is, the present invention includes the following: [1] A magnetic composition comprising (A) magnetic powder and (B) adhesive resin, Among them, the 10% particle size (D) in the particle size distribution of component (A) 10 The particle size is 1.7 μm or larger and 2.6 μm or smaller, with 50% of the particles having a diameter (D). 50 The particle size is 3.6 μm or larger and 12.0 μm or smaller, and 90% of the particle size (D) is within the acceptable range. 90 The size is 25.0 μm or larger and 51.0 μm or smaller. [2] According to the magnetic composition described in [1], wherein component (A) is a soft magnetic powder; [3] The magnetic composition according to [1] or [2], wherein (A) is any magnetic material among nanocrystalline magnetic materials and amorphous magnetic materials; [4] The magnetic composition according to any one of [1] to [3], wherein component (A) comprises ferroalloy metal powder; [5] The magnetic composition according to any one of [1] to [4], wherein (A) is any magnetic material among Fe-based nanocrystalline magnetic materials and Fe-based amorphous magnetic materials; [6] The magnetic composition according to any one of [1] to [5] is used to form a sensor element; [7] The magnetic composition according to any one of [1] to [6] is in the form of a paste; [8] The magnetic composition according to any one of [1] to [7] is used to fill through holes; [9] A magnetic sheet comprising: Support body, and A magnetic composition layer formed of any one of [1] to [8] is disposed on the support body;

[10] A circuit board comprising a magnetic layer, wherein the magnetic layer is a cured product of any one of the magnetic compositions described in [1] to [8];

[11] A circuit board having: Substrate with through holes, and A cured product of the magnetic composition described in any one of [1] to [8] that fills the through-hole;

[12] A sensor substrate comprising the circuit substrate described in

[10] or

[11] .

[0008] The effects of the invention According to the present invention, a magnetic composition capable of producing a cured material with increased relative permeability and reduced magnetic loss can be provided, as well as a magnetic sheet, a circuit board, and a sensor board obtained using the magnetic composition.

[0009] Brief description of the attached diagram Figure 1 This is a schematic cross-sectional view of a core substrate, which is an example of a method for manufacturing a circuit board according to the first embodiment. Figure 2 This is a schematic cross-sectional view of a core substrate with through holes, which is an example of a method for manufacturing a circuit board according to the first embodiment. Figure 3This is a schematic cross-sectional view showing the shape of a core substrate with a plating layer formed in a through hole, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 4 This is a schematic cross-sectional view showing the shape of a core substrate in which a magnetic composition is filled in the through-holes, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 5 This is a schematic cross-sectional view showing the shape of a core substrate after the filling magnetic composition has been thermo-cured, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 6 This is a schematic cross-sectional view showing the shape of a core substrate after the cured material has been polished, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 7 This is a schematic cross-sectional view showing the shape of a core substrate with a conductor layer formed on a polished surface, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 8 This is a schematic cross-sectional view showing the shape of a core substrate with a patterned conductor layer formed, as an example of a method for manufacturing a circuit board according to the first embodiment. Figure 9 This is a schematic cross-sectional view of step (A) included in an example of a method for manufacturing a circuit board according to the second embodiment. Figure 10 This is a schematic cross-sectional view of step (A) included in an example of a method for manufacturing a circuit board according to the second embodiment. Figure 11 This is a schematic cross-sectional view of step (B) included in an example of a method for manufacturing a circuit board according to the second embodiment. Figure 12 This is a schematic cross-sectional view of step (D) included in an example of a method for manufacturing a circuit board according to the second embodiment. Figure 13 This is a schematic top view of a sensor component viewed from one side in its thickness direction, as an example. The sensor component includes a circuit board obtained using the circuit board manufacturing method of the second embodiment. Figure 14 It indicates that as an example in Figure 13 The diagram shows a cut end face of a sensor component cut at the position indicated by the dotted line II-II. The sensor component includes a circuit board obtained using the circuit board manufacturing method of the second embodiment. Figure 15This is a schematic top view illustrating the configuration of a first conductor layer in a sensor component as an example, the sensor component comprising a circuit board obtained using the circuit board manufacturing method of the second embodiment. Detailed Implementation

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the drawings are merely simplified illustrations of the shape, size, and arrangement of the constituent elements to the extent that the invention can be understood. The present invention is not limited to the following embodiments, and the constituent elements may be appropriately modified. Furthermore, the configurations described in the embodiments of the present invention are not limited to manufacturing or use based on the configurations illustrated in the drawings.

[0011] [Magnetic Composition] The magnetic composition of the present invention comprises (A) magnetic powder and (B) binder resin, wherein 10% of the particle size distribution of component (A) is of magnetic powder (D) 10 The particle size is 1.7 μm or larger and 2.6 μm or smaller, with 50% of the particles having a diameter (D). 50 The particle size is 3.6 μm or larger and 12.0 μm or smaller, and 90% of the particle size (D) is within the acceptable range. 90 The particle size distribution is 25.0 μm or more and 51.0 μm or less. In this invention, by including magnetic powder with a specified particle size distribution in the magnetic composition, it is possible to simultaneously increase the relative permeability of the cured magnetic composition and reduce the magnetic loss.

[0012] The magnetic composition may further include (C) a curing accelerator, (D) a dispersant, and (E) other additives as needed. The components contained in the magnetic composition of the present invention will be described in detail below.

[0013] <(A) Magnetic Powder> In the magnetic composition, as component (A), magnetic powder is contained and has the following particle size distribution: 10% of the particle size distribution of component (A) is D 10 The particle size is 1.7 μm or larger and 2.6 μm or smaller, with 50% of the particles having a diameter (D). 50 The particle size is 3.6 μm or larger and 12.0 μm or smaller, and 90% of the particle size (D) is within the acceptable range. 90 The particle size distribution is 25.0 μm or larger and 51.0 μm or smaller. The above particle size distribution represents the overall particle size distribution of the (A) magnetic powder contained in the magnetic composition. By including component (A) in the magnetic composition, both the relative permeability of the cured product and the magnetic loss can be simultaneously increased.

[0014] (A) The particle size distribution of magnetic powder can be determined by laser diffraction scattering based on the Mie scattering theory. Specifically, the particle size distribution of magnetic powder can be determined using a laser diffraction scattering particle size distribution measuring device, with volume as the reference, and the 10% particle size (D) can be measured.10 ), 50% particle size (D 50 ), and 90% particle size (D 90 The sample to be measured is preferably a sample obtained by dispersing magnetic powder in pure water using ultrasound. As a laser diffraction scattering particle size distribution measuring device, the following can be used: MicrotracBEL's "MT3000II", Horiba Manufacturing Co., Ltd.'s "LA-960", and Shimadzu Corporation's "SALD-2200".

[0015] 10% of the particle size distribution (D) 10 50% particle size refers to the particle size at which the accumulated volume, starting from the smallest particle size side, reaches 10% of the particle size distribution as a result of particle size distribution determined by the above method. 50 This refers to the particle size at which the accumulated volume, starting from the smallest particle size side, reaches 50% in the particle size distribution determined by the above method. Furthermore, the 90% particle size (D...) 90 (A) refers to the particle size at which the accumulated volume from the smallest particle size side reaches 90% in the particle size distribution determined by the above method. Here, (A) the average particle size of the magnetic powder refers to the 50% particle size (D) 50 The particle size is 10%. Below that, sometimes 10% of the particle size (D) is used. 10 ) is called D 10 50% of the particle size (D) 50 ) is called D 50 and 90% of the particle size (D) 90 ) is called D 90 .

[0016] D in particle size distribution 10 From the viewpoint of simultaneously achieving an increase in the relative permeability and a reduction in magnetic loss of the cured magnetic composition, a permeability of 1.7 μm or more is preferable, 1.8 μm or more is more preferably 1.9 μm or more. The upper limit is 2.6 μm or less, preferably 2.5 μm or less, and more preferably 2.4 μm or less.

[0017] D in particle size distribution 50 From the viewpoint of simultaneously achieving an increase in the relative permeability and a reduction in magnetic loss of the cured magnetic composition, a diameter of 3.6 μm or more is preferable, 4.0 μm or more is preferable, and 5.0 μm or more is even more preferable. The upper limit is 12.0 μm or less, preferably 11.0 μm or less, and even more preferably 10.0 μm or less.

[0018] D in particle size distribution 90From the viewpoint of simultaneously achieving an increase in the relative permeability and a reduction in magnetic loss of the cured magnetic composition, a permeability of 25.0 μm or more is preferable, 26.0 μm or more is preferable, and 27.0 μm or more is even more preferable. The upper limit is 51.0 μm or less, preferably 50.0 μm or less, and even more preferably 49.0 μm or less.

[0019] As D 50 -D 10 From the viewpoint of significantly obtaining the effects of the present invention, it is preferable that the nanometer size is 1.0 μm or more, more preferably 1.1 μm or more, and even more preferably 1.2 μm or more. The upper limit is preferably 10.3 μm or less, more preferably 10.2 μm or less, and even more preferably 10.1 μm or less.

[0020] As D 90 -D 10 From the viewpoint of significantly achieving the effects of the present invention, a nanometer diameter of 22.4 μm or more is preferred, 22.5 μm or more is more preferably 22.6 μm or more is preferred. The upper limit is preferably 49.3 μm or less, more preferably 49.2 μm or less, and even more preferably 49.1 μm or less.

[0021] As D 90 -D 50 From the viewpoint of significantly obtaining the effects of the present invention, a nanometer diameter of 13 μm or more is preferred, 14 μm or more is more preferably preferred, and 15 μm or more is even more preferably preferred. The upper limit is preferably 47.4 μm or less, more preferably 47.0 μm or less, and even more preferably 46.0 μm or less.

[0022] As D 90 / D 50 From the viewpoint of significantly achieving the effects of the present invention, a value of 14.17 or less is preferred, 12.75 or less is more preferably preferred, and 10.20 or less is even more preferably preferred. The lower limit is preferably 2.08 or more, more preferably 2.27 or more, and even more preferably 2.50 or more.

[0023] As D 90 / D 10 From the viewpoint of significantly achieving the effects of the present invention, a value of 30.0 or less is preferred, 28.3 or less is more preferably preferred, and 26.8 or less is even more preferably preferred. The lower limit is preferably 9.62 or more, more preferably 10 or more, and even more preferably 10.4 or more.

[0024] As D 50 / D 10 From the viewpoint of achieving significant effects of the present invention, a value of 7.06 or less is preferred, 6.67 or less is more preferably preferred, and 6.32 or less is even more preferably preferred. The lower limit is preferably 1.38 or more, more preferably 1.44 or more, and even more preferably 1.89 or more.

[0025] As for (A) magnetic powder, it can be any of soft magnetic powder or hard magnetic powder, but from the viewpoint of suppressing the segregation (uneven distribution) of magnetic powder, soft magnetic powder is preferred.

[0026] From the viewpoint that both the relative permeability of the cured magnetic composition and the magnetic loss can be simultaneously increased, (A) the magnetic powder is preferably any magnetic material selected from nanocrystalline magnetic materials and amorphous magnetic materials. From the viewpoint that magnetic loss can be reduced by decreasing the magnetic anisotropy of the crystals, nanocrystalline magnetic materials are more preferable. In this specification, nanocrystalline magnetic materials are magnetic materials containing grains, referring to magnetic materials in which the grain size of the magnetic powder is 100 nm or less, and preferably the maximum grain size is 100 nm or less. Typically, a single particle of the (A) magnetic powder contains multiple grains, and the particles can be polycrystalline. The size of the grains can be observed, for example, using TEM (transmission electron microscopy). Nanocrystalline magnetic materials contain grains, and therefore typically show peaks exhibiting crystallinity (crystalline properties) in X-ray diffraction patterns. Furthermore, amorphous magnetic materials are amorphous magnetic materials, referring to materials that do not show specific peaks exhibiting crystallinity in X-ray diffraction patterns. Typically, X-ray diffraction patterns of amorphous magnetic materials show broad peaks that do not indicate crystalline properties. By making the magnetic powder (A) any magnetic material, including nanocrystalline and amorphous magnetic materials, a high magnetic flux density is achieved. As a result, it is believed that both the relative permeability and magnetic loss can be effectively increased.

[0027] Examples of (A) magnetic powders include iron alloy metal powders (Fe-based metal powders), such as Fe-Si alloy powders, Fe-Si-Al alloy powders, Fe-Cr alloy powders, Fe-Cr-Si alloy powders, Fe-Ni-Cr alloy powders, Fe-Cr-Al alloy powders, Fe-Ni alloy powders, Fe-Ni-Mo alloy powders, Fe-Ni-Mo-Cu alloy powders, Fe-Co alloy powders, or Fe-Ni-Co alloy powders.

[0028] Of which, from the viewpoint of significantly obtaining the effects of the present invention, the magnetic powder (A) is preferably an iron alloy-based metal powder. As an iron alloy-based metal powder, it is preferably an iron alloy-based metal powder containing at least one element selected from Fe, Si, Cr, Al, Ni, and Co; more preferably, it is an iron alloy-based metal powder containing Fe, Si, and Cr. Furthermore, it is more preferably any magnetic material containing at least one element selected from Fe, Si, Cr, Al, Ni, and Co, either nanocrystalline or amorphous; even more preferably, it is any magnetic material containing Fe, Si, and Cr, either nanocrystalline or amorphous; more preferably, it is any magnetic material containing Fe-based nanocrystalline or Fe-based amorphous magnetic materials; and most preferably, it is a Fe-based nanocrystalline magnetic material. Here, Fe-based means containing Fe atoms.

[0029] (A) The magnetic powder can be adjusted to a specified particle size distribution, for example, by grading. Furthermore, the aforementioned particle size distribution refers to the overall particle size distribution of component (A) contained in the magnetic composition. Therefore, component (A) formed by mixing two or more magnetic powders can be adjusted to have a specified particle size distribution, for example, by mixing multiple magnetic powders that do not have a specified particle size distribution, as long as component (A) as a whole has a specified particle size distribution.

[0030] (A) Magnetic powder can be used alone or in combination with two or more, but from the viewpoint of significantly obtaining the effects of the present invention, it is preferable to use two or more magnetic powders in combination, and more preferably to use two or more magnetic powders with different average particle sizes in combination. As one embodiment, when two magnetic powders with different average particle sizes are used in combination, the average particle size of one of the magnetic powders is preferably 0.01 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. Furthermore, it is preferably less than 10 μm, more preferably 9 μm or less, and even more preferably 8 μm or less. The average particle size of the other magnetic powder is preferably 10 μm or more, more preferably 13 μm or more, and even more preferably 15 μm or more. Furthermore, it is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 23 μm or less.

[0031] When two or more magnetic powders with different average particle sizes are used together, if the average particle size of one magnetic powder is set as a1 and the average particle size of the other magnetic powder is set as a2, then the ratio of a1 / a2 is preferably 1 or more, more preferably 3 or more, even more preferably 5 or more, preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less. Wherein, a1 > a2. By adjusting a1 / a2 to fall within the aforementioned range, the effects of the present invention can be significantly obtained.

[0032] As for (A) magnetic powder, commercially available products can be used, or two or more can be used together. Specific examples of commercially available magnetic powders that can be used include "KUAMET NC1" and "ATFINE NC1" (nanocrystalline magnetic materials) manufactured by EPSON ATMIX; "KUAMET 6B2" and "AW02-08PF3F" (amorphous magnetic materials) manufactured by EPSON ATMIX, etc.

[0033] (A) The magnetic powder is preferably spherical. The aspect ratio (length-to-width ratio) obtained by dividing the major axis length by the minor axis length of the magnetic powder is preferably 2 or less, more preferably 1.5 or less, even more preferably 1.2 or less, more preferably greater than 1, and more preferably 1.05 or more. Generally, when the magnetic powder is a non-spherical, flat shape, it is easier to increase the relative permeability. However, in this invention, from the viewpoint of reducing magnetic loss and from the viewpoint of obtaining a magnetic composition with better viscosity, it is preferable to use spherical magnetic powder.

[0034] From the perspective of increasing relative permeability, (A) the specific surface area of ​​the magnetic powder is preferably 0.05 m². 2 / g or higher, preferably 0.1m 2 / g or higher, and even better is 0.3m 2 / g or more. Furthermore, 15m is preferred. 2 Below / g, 12m is better. 2 Below / g, even better is 10m 2 / g or less. (A) The specific surface area of ​​magnetic powder can be determined by the BET method.

[0035] From the viewpoint of increasing relative permeability and reducing magnetic loss, when the non-volatile component in the magnetic composition is set to 100% by volume, the content (by volume) of magnetic powder (A) is preferably 10% by volume or more, more preferably 20% by volume or more, and even more preferably 30% by volume or more. Furthermore, it is preferably 95% by volume or less, more preferably 90% by volume or less, and even more preferably 80% by volume or less.

[0036] From the viewpoint of increasing relative permeability and reducing magnetic loss, when the non-volatile component in the magnetic composition is set to 100% by mass, the content (by mass%) of magnetic powder (A) is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. Furthermore, it is preferably 99.5% by mass or less, more preferably 99% by mass or less, and even more preferably 98% by mass or less. It should be noted that, in this invention, the content of each component in the magnetic composition, unless otherwise specified, refers to the value when the non-volatile component in the magnetic composition is set to 100% by mass.

[0037] <(B) Adhesive Resin> The magnetic composition contains an adhesive resin as component (B). Examples of adhesive resins (B) include thermosetting resins such as epoxy resins, phenolic resins, naphthol resins, benzoxazine resins, reactive ester resins, cyanate ester resins, carbodiimide resins, amine resins, and anhydride resins; and thermoplastic resins such as phenoxy resins, acrylic resins, polyvinyl acetal resins, butyraldehyde resins, polyimide resins, polyamide-imide resins, polyethersulfone resins, and polysulfone resins. Component (B) may contain thermosetting resins, thermoplastic resins, or a combination of both. The adhesive resin (B) is preferably a thermosetting resin used in forming the insulating layer of the wiring board, and is preferably an epoxy resin. The adhesive resin (B) may be used alone or in combination of two or more. The following describes each resin.

[0038] Here, components that react with epoxy resin to cure the magnetic composition, such as phenolic resins, naphthol resins, benzoxazine resins, reactive ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins, are sometimes collectively referred to as "curing agents".

[0039] -Thermosetting resin- Examples of epoxy resins as thermosetting resins include: glycirol type epoxy resins; bisphenol A type epoxy resins; bisphenol F type epoxy resins; bisphenol S type epoxy resins; bisphenol AF type epoxy resins; dicyclopentadiene type epoxy resins; triphenol type epoxy resins; phenol novolac type epoxy resins; tert-butyl-catechol type epoxy resins; naphthol novolac type epoxy resins; naphthalene type epoxy resins; naphthol type epoxy resins; anthracene type epoxy resins; glycidylamine type epoxy resins; glycidyl ester type epoxy resins; cresol novolac type epoxy resins; and other epoxy resins with fused ring structures. Novolac type epoxy resins include: biphenyl type epoxy resins; linear aliphatic epoxy resins; epoxy resins with butadiene structure; alicyclic epoxy resins; heterocyclic epoxy resins; epoxy resins containing spirocyclic rings; cyclohexanediol type epoxy resins; trimethylol type epoxy resins; tetraphenylethane type epoxy resins, etc. Epoxy resins can be used alone or in combination of two or more. Preferably, the epoxy resin is selected from one or more of bisphenol A type epoxy resins and bisphenol F type epoxy resins.

[0040] Epoxy resins preferably include those having two or more epoxy groups per molecule. Furthermore, epoxy resins preferably have an aromatic structure; when using two or more epoxy resins, it is even more preferable that at least one has an aromatic structure. An aromatic structure refers to a chemical structure generally defined as aromatic, including polycyclic aromatics and aromatic heterocycles. The proportion of epoxy resins having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the epoxy resin.

[0041] Epoxy resins include epoxy resins that are liquid at 25°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 25°C (hereinafter sometimes referred to as "solid epoxy resins"). When epoxy resin is included as component (B), the epoxy resin may consist only of liquid epoxy resin, or only of solid epoxy resin, or a combination of both. From the viewpoint of reducing the viscosity of the resin composition, it is preferable that the epoxy resin consists only of liquid epoxy resin.

[0042] As liquid epoxy resins, glycirol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, phenolic varnish type epoxy resins, alicyclic epoxy resins with ester skeletons, cyclohexanediol type epoxy resins, and epoxy resins with butadiene structures are preferred, and glycirol type epoxy resins, bisphenol A type epoxy resins, and bisphenol F type epoxy resins are even more preferred. Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US", "jER828EL" (bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), and "jER152" (phenolic varnish type epoxy resin); Mitsubishi Chemical's "630" and "630LSD"; ADEKA's "ED-523T" (epoxypropoxy type epoxy resin (ADEKA Glycirol)), "EP-3980S" (glycidylamine type epoxy resin), and "EP-4088S" (dicyclopentadiene type epoxy resin); and NIPPON STEEL Chemical & Material Co., Ltd. The following epoxy resins are available: "ZX1059" (a mixture of bisphenol A and bisphenol F epoxy resins) manufactured by [Company Name]; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX; "CELLOXIDE2021P" (an alicyclic epoxy resin with an ester skeleton) and "PB-3600" (an epoxy resin with a butadiene structure) manufactured by Daicel; and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical Materials Co., Ltd. These can be used individually or in combination.

[0043] As solid epoxy resins, naphthalene-type tetrafunctional epoxy resins, cresol-phenolic varnish-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, and tetraphenylethane-type epoxy resins are preferred, and naphthalene-type tetrafunctional epoxy resins, naphthol-type epoxy resins, and biphenyl-type epoxy resins are even more preferred. Specific examples of solid epoxy resins include: DIC's "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" (cresol phenolic varnish type epoxy resin), "N-695" (cresol phenolic varnish type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "HP-7200HH", "HP-7200H", "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthyl ether type epoxy resin); and Nippon Kayaku Co., Ltd.'s "EPPN-502H" (triphenol type epoxy resin), "NC7000L" (naphthalene phenolic varnish type epoxy resin), and "N..." C3000H, NC3000, NC3000L, and NC3100 (biphenyl type epoxy resin); Nippon Steel Chemical Materials Co., Ltd.'s ESN475V (naphthalene type epoxy resin) and ESN485 (naphthol phenolic varnish type epoxy resin); Mitsubishi Chemical Co., Ltd.'s YX4000H, YL6121 (biphenyl type epoxy resin), YX4000HK (bixylenol type epoxy resin), and YX8800 (anthracite type epoxy resin); Osaka Gas Chemical Co., Ltd.'s PG-100 and CG-500; Mitsubishi Chemical Co., Ltd.'s YL7760 (bisphenol AF type epoxy resin), YL7800 (fluorene type epoxy resin), jER1010 (solid bisphenol A type epoxy resin), and jER1031S (tetraphenylethane type epoxy resin), etc. These can be used individually or in combination.

[0044] As component (B), when liquid epoxy resin and solid epoxy resin are used, the mass ratio of them (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1:4, more preferably 1:0.3 to 1:3.5, and even more preferably 1:0.6 to 1:3.

[0045] The epoxy equivalent of the epoxy resin as component (B) is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., even more preferably 80 g / eq. to 2000 g / eq., and even more preferably 110 g / eq. to 1000 g / eq. By falling within this range, the crosslinking density of the cured product becomes sufficient, resulting in a magnetic layer with low surface roughness. It should be noted that the epoxy equivalent can be determined according to JIS K7236 and is the mass of resin containing 1 equivalent of epoxy groups.

[0046] The weight-average molecular weight of the epoxy resin as component (B) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. Here, the weight-average molecular weight of the epoxy resin is the weight-average molecular weight converted from polystyrene by gel permeation chromatography (GPC).

[0047] As an active ester resin, a resin having one or more active ester groups per molecule can be used. Among these, resins having two or more highly reactive ester groups per molecule, such as phenolic esters, thiophenolic esters, N-hydroxyamine esters, and esters of heterocyclic hydroxyl compounds, are preferred. This active ester resin is preferably a compound obtained through a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxyl compound and / or a thiol compound. Particularly from the viewpoint of improved heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxyl compound is preferred, and an active ester resin obtained from a carboxylic acid compound and a phenolic compound (phenol compound) and / or a naphthol compound is even more preferred.

[0048] Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0049] Examples of phenolic or naphthol compounds include: hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, pyroglucinol, dicyclopentadiene-type diphenol compounds, and linear phenolic resins. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

[0050] Examples of suitable reactive ester resins include: reactive ester resins containing a dicyclopentadiene-type diphenol structure, reactive ester resins containing a naphthalene structure, reactive ester resins containing acetylated derivatives of linear phenolic resins, and reactive ester resins containing benzoyl derivatives of linear phenolic resins. Among these, reactive ester resins containing a naphthalene structure and reactive ester resins containing a dicyclopentadiene-type diphenol structure are more preferred. "Dicyclopentadiene-type diphenol structure" refers to a divalent structural unit formed from a phenylene-dicyclopentylene-phenylene group.

[0051] Regarding commercially available reactive ester resins, examples of reactive ester resins containing a dicyclopentadiene-type diphenol structure include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", and "EXB-8000L-65TM" (manufactured by DIC Corporation); examples of reactive ester resins containing a naphthalene structure include "EXB9416-70BK" and "EXB-8150-65T" (manufactured by DIC Corporation); and examples of acetylated linear phenolic resins... Examples of active ester resins include "DC808" (manufactured by Mitsubishi Chemical Corporation); examples of active ester resins containing benzoyl derivatives of linear phenolic resins include "YLH1026" (manufactured by Mitsubishi Chemical Corporation); examples of active ester resins containing acetylated derivatives of linear phenolic resins include "DC808" (manufactured by Mitsubishi Chemical Corporation); examples of active ester resins containing benzoyl derivatives of linear phenolic resins include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation).

[0052] From the viewpoint of heat resistance and water resistance, resins with a linear phenolic structure are preferred as phenolic resins and naphthol resins. Furthermore, from the viewpoint of adhesion to the conductor layer, nitrogen-containing phenolic curing agents are preferred, and phenolic resins containing a triazine backbone are even more preferred.

[0053] Specific examples of phenolic resins (phenolic resins) and naphthol resins include: "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Corporation; "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN495V", "SN375", and "SN395" manufactured by Nippon Steel Chemical Materials Co., Ltd.; and "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

[0054] Specific examples of benzoxazine resins include: JFE Chemical Co., Ltd.'s "JBZ-OD100" (benzoxazine ring equivalent 218), "JBZ-OP100D" (benzoxazine ring equivalent 218), and "ODA-BOZ" (benzoxazine ring equivalent 218); Shikoku Chemical Industry Co., Ltd.'s "Pd" (benzoxazine ring equivalent 217) and "Fa" (benzoxazine ring equivalent 217); and Showa Polymer Co., Ltd.'s "HFB2006M" (benzoxazine ring equivalent 432), etc.

[0055] Examples of difunctional cyanate resins include: bisphenol A dicyanate, polyphenol cyanate, oligomeric (3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanoesteryl)phenylpropane, 1,1-bis(4-cyanoesterylphenylmethane), bis(4-cyanoesteryl-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanoesterylphenyl-1-(methylethylene))benzene, bis(4-cyanoesterylphenyl) sulfide, and bis(4-cyanoesterylphenyl) ether; polyfunctional cyanate resins derived from phenolic varnish resins and cresol varnish resins; and prepolymers obtained by triazinizing some of these cyanate resins. Specific examples of cyanate ester resins include Lonza Japan's "PT30" and "PT60" (both phenolic varnish-type multifunctional cyanate ester resins), "ULL-950S" (multifunctional cyanate ester resin), "BA230", and "BA230S75" (prepolymers in which some or all of the bisphenol A dicyanate is triazineized to form a trimer).

[0056] Specific examples of carbodiimide resins include: CARBODILITE (registered trademark) V-03 (carbodiimide equivalent: 216), V-05 (carbodiimide equivalent: 262), V-07 (carbodiimide equivalent: 200), and V-09 (carbodiimide equivalent: 200) manufactured by Nisshinbo Chemical Co., Ltd.; and Stabaxol (registered trademark) P (carbodiimide equivalent: 302) manufactured by Rhein Chemie.

[0057] As amine resins, examples include resins having one or more amino groups per molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. From the viewpoint of achieving the desired effect of this invention, aromatic amines are preferred. The amine resin is preferably a primary or secondary amine, and more preferably a primary amine. Specific examples of amine curing agents include: 4,4'-methylenebis(2,6-dimethylaniline), diphenyl diamino sulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-phenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino) 4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Amine resins can be commercially available products, such as: "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd., and "Epicure (エピキュア)W" manufactured by Mitsubishi Chemical Co., Ltd.

[0058] As anhydride-based resins, resins having one or more anhydride groups within one molecule can be cited. Specific examples of anhydride-based resins include: phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, and pyromellitic anhydride. Benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl sulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(triphenyl phthalic anhydride), styrene-maleic acid resin obtained by copolymerization of styrene and maleic acid, and other polymeric anhydrides.

[0059] When component (B) contains epoxy resin and curing agent, the ratio of epoxy resin to all curing agent, in terms of the ratio of [total number of epoxy groups in the epoxy resin] to [total number of reactive groups in the curing agent], is preferably in the range of 1:0.01 to 1:5, more preferably in the range of 1:0.5 to 1:3, and even more preferably in the range of 1:1 to 1:2. Here, "number of epoxy groups in the epoxy resin" refers to the sum of all values ​​obtained by dividing the mass of the non-volatile component of the epoxy resin present in the magnetic composition by the epoxy equivalent. Furthermore, "number of active groups (reactive groups) in the curing agent" refers to the sum of all values ​​obtained by dividing the mass of the non-volatile component of the curing agent present in the magnetic composition by the active group equivalent.

[0060] -Thermoplastic resin- The weight-average molecular weight of thermoplastic polystyrene is preferably 30,000 or higher, more preferably 50,000 or higher, and even more preferably 100,000 or higher. Furthermore, it is preferably 1,000,000 or lower, more preferably 750,000 or lower, and even more preferably 500,000 or lower. The weight-average molecular weight of thermoplastic polystyrene is determined by gel permeation chromatography (GPC). Specifically, for the weight-average molecular weight of thermoplastic polystyrene, a Shimadzu Corporation "LC-9A / RID-6A" instrument is used as the measuring apparatus, a Showa Denko Corporation "Shodex K-800P / K-804L / K-804L" column is used as the column, chloroform or similar is used as the mobile phase, the column temperature is set to 40°C, and the molecular weight is calculated using a calibration curve of standard polystyrene.

[0061] Examples of phenoxy resins include those having one or more skeletons selected from the following: bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetylphenyl skeleton, phenolic (novolac) skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The terminal group of the phenoxy resin can be any functional group such as phenolic hydroxyl group or epoxy group. A single phenoxy resin can be used, or two or more can be used in combination. Specific examples of phenoxy resins include Mitsubishi Chemical's "1256" and "4250" (both containing a bisphenol A backbone), "YX8100" (containing a bisphenol S backbone), and "YX6954" (containing a bisphenol acetylbenzene backbone). Other examples include Nippon Steel Chemical Materials' "FX280" and "FX293," and Mitsubishi Chemical's "YL7500BH30," "YX6954BH30," "YX7553," "YX7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," and "YL7482," etc.

[0062] From the viewpoint of further reducing the coefficient of thermal expansion and the modulus of elasticity, acrylic resins containing functional groups are preferred, and acrylic resins containing epoxy groups with a glass transition temperature of 25°C or lower are even more preferred.

[0063] The number average molecular weight (Mn) of acrylic resins containing functional groups is preferably 10,000 to 1,000,000, and more preferably 30,000 to 900,000.

[0064] The functional group equivalent of acrylic resins containing functional groups is preferably 1,000 to 50,000, and more preferably 2,500 to 30,000.

[0065] As for epoxy-containing acrylic resins with a glass transition temperature below 25°C, epoxy-containing acrylate copolymer resins with a glass transition temperature below 25°C are preferred. Specific examples include "SG-80H" (epoxy-containing acrylate copolymer resin (number average molecular weight Mn: 350,000 g / mol, epoxy value: 0.07 eq / kg, glass transition temperature: 11°C)) manufactured by Nagase ChemteX and "SG-P3" (epoxy-containing acrylate copolymer resin (number average molecular weight Mn: 850,000 g / mol, epoxy value: 0.21 eq / kg, glass transition temperature: 12°C)) manufactured by Nagase ChemteX.

[0066] Specific examples of polyvinyl alcohol acetal resin and butyraldehyde resin include Denka Butyral "4000-2", "5000-A", "6000-C" and "6000-EP" manufactured by Denka Kogyo Co., Ltd., and S-LEC BH series, BX series, KS series such as "KS-1", BL series such as "BL-1" and BM series manufactured by Sekisui Chemicals Co., Ltd.

[0067] Specific examples of polyimide resins include "RIKACOAT SN20" and "RIKACOAT PN20" manufactured by Shin Nippon Rikka Co., Ltd. Other specific examples of polyimide resins include linear polyimides (the polyimide described in Japanese Patent Application Publication No. 2006-37083) obtained by reacting difunctional hydroxyl-terminated polybutadiene, diisocyanate compounds, and tetrabasic anhydrides, and modified polyimides containing a polysiloxane backbone (the polyimides described in Japanese Patent Application Publication Nos. 2002-12667 and 2000-319386, etc.).

[0068] Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Other examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imide containing a polysiloxane backbone) manufactured by Hitachi Chemical Industries Co., Ltd.

[0069] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. Specific examples of polyphenylene ether resins include "OPE-2St 1200," a vinyl-containing low-polyphenylene ether-styrene resin manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0070] Specific examples of polysulfone resins include polysulfones such as "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0071] Among them, the thermoplastic resin is preferably a thermoplastic resin selected from phenoxy resin, polyvinyl acetal resin, butyraldehyde resin and acrylic resin, with a weight average molecular weight of 30,000 or more and less than 1 million.

[0072] From the viewpoint of obtaining a magnetic layer exhibiting good mechanical strength and insulation reliability, when the non-volatile component in the magnetic composition is set to 100% by mass, the content of the (B) adhesive resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 1% by mass or more. There is no particular upper limit as long as the effects of the present invention are achieved, but it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0073] Furthermore, the adhesive resin in (B) preferably includes epoxy resin, and more preferably includes liquid epoxy resin. The liquid epoxy resin accounts for 1% or more of the total mass of component (A), more preferably 1.5% or more, and even more preferably 2% or more. The maximum percentage is preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less.

[0074] <(C) Curing Accelerator> The magnetic composition may further include (C) a curing accelerator as an optional component.

[0075] Examples of curing accelerators include amine-based, imidazole-based, phosphorus-based, guanidine-based, and metal-based curing accelerators. From the viewpoint of reducing the viscosity of the magnetic composition, amine-based or imidazole-based curing accelerators are preferred, with imidazole-based accelerators being more desirable. A single curing accelerator can be used, or two or more can be used in combination.

[0076] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo[5.4.0]undecene, with 4-dimethylaminopyridine and 1,8-diazabicyclo[5.4.0]undecene being preferred.

[0077] As amine-based curing accelerators, commercially available products can be used, such as "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine-Techno.

[0078] Examples of imidazole-based curing accelerators include: 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine, 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecanylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2 1-Methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole ontyl trimellitate, 1-cyanoethyl-2-phenylimidazole ontyl trimellitate, 2,4-diamino-6-[2'-methylimidazole-( 1')]-Ethyl-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl -4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline and other imidazole compounds, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazolium and 1-benzyl-2-phenylimidazolium.

[0079] As an imidazole-based curing accelerator, commercially available products can be used, such as "2P4MZ" and "2PHZ-PW" manufactured by Shikoku Chemical Industry Co., Ltd., and "P200-H50" manufactured by Mitsubishi Chemical Co., Ltd.

[0080] Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc., with triphenylphosphine and tetrabutylphosphonium decanoate being preferred.

[0081] Examples of guanidine-based 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-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, 1-(o-tolyl)biguanidine, etc., with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

[0082] Examples of metal-based curing accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt(II) and cobalt(III) acetylacetone, organocopper complexes such as copper(II) acetylacetone, organozinc complexes such as zinc(II) acetylacetone, organoiron complexes such as iron(III) acetylacetone, organonickel complexes such as nickel(II) acetylacetone, and organomanganese complexes such as manganese(II) acetylacetone. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0083] As the (C) curing accelerator, from the viewpoint of obtaining the desired effect of the present invention, it is preferably selected from at least one of anhydride-based epoxy resin curing agents, amine-based curing accelerators and imidazole-based curing accelerators, and more preferably selected from at least one of amine-based curing accelerators and imidazole-based curing accelerators.

[0084] From the viewpoint of promoting the curing of the magnetic composition, when the non-volatile component in the magnetic composition is set to 100% by mass, the content of (C) curing accelerator is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0.1% by mass or less.

[0085] <(D) Dispersant> The magnetic composition may further include (D) a dispersant as an optional component.

[0086] Examples of dispersants (D) include: phosphate ester dispersants such as polyoxyethylene alkyl ether phosphates; anionic dispersants such as sodium dodecylbenzenesulfonate, sodium laurate, and ammonium salts of polyoxyethylene alkyl ether sulfates; and nonionic dispersants such as organosiloxane dispersants, acetylene glycol, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, and polyoxyethylene alkylamides. Anionic dispersants are preferred. A single dispersant may be used, or two or more may be used in combination.

[0087] Phosphate ester dispersants can be commercially available. Examples of commercially available products include "RS-410", "RS-610", and "RS-710" from the "Phosphanol" series manufactured by Toho Chemical Industry Co., Ltd.

[0088] As organosiloxane dispersants, commercially available examples include "BYK347" and "BYK348" manufactured by BYK-Chemie.

[0089] As polyoxyethylene-based dispersants, commercially available products include: "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F" and "SC-0708A", as well as "HKM-50A" from the "MALIALIM" series manufactured by Nippon Oil Co., Ltd.

[0090] As acetylene glycol, commercially available products include: the "Surfynol" series "82", "104", "440", "465" and "485" manufactured by Air Products and Chemicals Inc., as well as "Olefin Y".

[0091] From the viewpoint that the effects of the present invention can be made significant, when the non-volatile component in the magnetic composition is set to 100% by mass, the content of the dispersant (D) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0092] <(E) Other Additives> For magnetic compositions, other additives may be further included as needed. Examples of such other additives include: curing delay agents such as triethyl borate for improving pot life; inorganic fillers (excluding materials that are magnetic powders); flame retardants; organic fillers; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; and resin additives such as thickeners, defoamers, leveling agents, adhesion promoters, and colorants.

[0093] The magnetic composition can be a paste-like composition that typically exhibits low viscosity even without the presence of a solvent. Therefore, the solvent content in the magnetic composition, relative to the total mass of the magnetic composition, is preferably less than 1.0% by mass, more preferably less than 0.8% by mass, further preferably less than 0.5% by mass, and particularly preferably less than 0.1% by mass. There is no particular limitation on the lower limit; it can be more than 0.001% by mass, or solvent-free. By using a typically liquid thermosetting resin or the like, the viscosity of the magnetic composition can be reduced even without the presence of a solvent. By keeping the amount of solvent in the magnetic composition low, the formation of voids caused by solvent evaporation can be suppressed, and processability and operability can also be improved.

[0094] <Method for manufacturing magnetic composition> The magnetic composition can be manufactured, for example, by stirring the admixtures using a stirring device such as a three-roll mill or a rotary mixer.

[0095] <Physical properties of magnetic compositions, etc.> The magnetic composition contains component (A) with a specified particle size distribution, and therefore the cured magnetic composition exhibits a high relative permeability. Thus, the cured magnetic composition results in a magnetic layer with high relative permeability. The relative permeability of this cured composition at a frequency of 10 MHz is preferably 15 or higher, more preferably 17 or higher, and even more preferably 19 or higher. Furthermore, there is no particular upper limit, and it can be set to 100 or lower, etc. The relative permeability can be measured according to the method described in the examples described later.

[0096] The magnetic composition contains component (A) with a specified particle size distribution, and therefore the cured magnetic composition exhibits low magnetic loss. Thus, the cured magnetic composition provides a magnetic layer with low magnetic loss. The magnetic loss of this cured composition at a frequency of 10 MHz is preferably less than 0.08, more preferably less than 0.05, and even more preferably less than 0.04 and less than 0.05. The lower limit is not particularly limited and can be set to 0.0001 or higher, etc. The magnetic loss can be measured according to the method described in the examples below.

[0097] Magnetic compositions typically exhibit low viscosity. Therefore, the paste-like nature of the magnetic composition (pasty magnetic composition) makes it ideal for use as a magnetic composition for filling through-holes. Furthermore, the magnetic composition is also ideal for use as a magnetic composition for forming sensor elements in the manufacture of sensor elements.

[0098] [Magnetic Sheets] The magnetic sheet includes a support and a magnetic composition layer formed of the magnetic composition of the present invention disposed on the support.

[0099] From the perspective of thinning, the thickness of the magnetic composition layer is preferably less than 250 μm, and more preferably less than 200 μm. There is no particular limitation on the lower limit of the thickness of the magnetic composition layer, and it can usually be set to more than 5 μm, more than 10 μm, etc.

[0100] Examples of supports include films made of plastic materials, metal foils, and release paper, with films and metal foils made of plastic materials being preferred.

[0101] When a film formed of a plastic material is used as a support, examples of plastic materials include: polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), acrylic polymers such as polycarbonate (hereinafter sometimes abbreviated as "PC") and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0102] When using metal foil as a support, examples of metal foils include copper foil and aluminum foil, with copper foil being preferred. Copper foil can be used as the support, either as a single metal of copper or as an alloy of copper with other metals (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

[0103] The surface of the support body that is bonded to the magnetic composition layer can be treated with matte finish or corona treatment.

[0104] Furthermore, as a support, a support with a release layer can be used on the surface bonded to the magnetic composition layer. Examples of release agents used in the release layer of the support with the release layer include, for example, one or more release agents selected from alkyd resins, polyolefin resins, polyurethane resins, and silicone resins. Commercially available products can be used as the support with the release layer, such as: PET films with a release layer primarily composed of an alkyd resin-based release agent, such as Lintec Corporation's "PET501010", "SK-1", "AL-5", and "AL-7"; Toray Industries' "Lumirror T60"; Teijin Corporation's "Purex"; and UNITIKA Corporation's "Unipeel".

[0105] The thickness of the support is not particularly limited, but it is preferably in the range of 5μm to 75μm, and more preferably in the range of 10μm to 60μm. It should be noted that when using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0106] In magnetic sheets, a protective film, selected according to the support, can be laminated onto the side of the magnetic composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but can be, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to prevent the adhesion of debris or other contaminants to the surface of the magnetic composition layer, or to prevent damage. The magnetic sheet can be stored in rolls. When the magnetic sheet has a protective film, it can be used by peeling off the protective film.

[0107] Magnetic sheets can be manufactured, for example, by coating a magnetic composition onto a support using a die coater or similar machine to form a magnetic composition layer. A resin varnish dissolved in an organic solvent can be prepared, and this resin varnish can be coated onto the support, if necessary. When using an organic solvent, drying can be performed after coating, if required.

[0108] Drying can be carried out by methods such as heating or hot air blowing. There are no particular limitations on drying conditions; drying is generally carried out when the content of organic solvent in the magnetic composition layer is 10% by mass or less, preferably 5% by mass or less. Although the specific conditions may vary depending on the components contained in the magnetic composition, the magnetic composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0109] Magnetic sheets can be rolled up for storage. If the magnetic sheet has a protective film, it can be used by peeling off the protective film.

[0110] [Circuit substrate and its manufacturing method] The circuit board of the present invention includes a magnetic layer as a cured magnetic composition. The circuit board of the first embodiment includes a substrate having through holes and a cured magnetic composition of the present invention filling the through holes. Furthermore, the circuit board of the second embodiment includes a magnetic layer formed from a cured magnetic composition layer of a magnetic sheet. Hereinafter, a first embodiment and a second embodiment of the circuit board manufacturing method will be described. However, the circuit board manufacturing method of the present invention is not limited to the first and second embodiments described below.

[0111] <First Implementation> The circuit board of the first embodiment can be manufactured, for example, by a manufacturing method comprising the following steps (1) to (5). In the first embodiment, it is preferable to form a magnetic layer using a magnetic composition, and more preferably to form a magnetic layer using a paste-like magnetic composition. The manufacturing method comprises: (1) A process of filling a magnetic composition into a through hole of a substrate having a through hole; (2) A process of heat curing the magnetic composition to obtain a cured product; (3) A process of grinding the surface of a cured material or a magnetic composition; (4) The process of roughening the cured material; and (5) The process of forming a conductor layer on the roughened surface of the cured material; The method for manufacturing the circuit board of the present invention can be carried out in the order of steps (1) to (5), or step (2) can be carried out after step (3).

[0112] <Process (1)> The process of step (1) may include a step of preparing a magnetic composition. The magnetic composition is as described above.

[0113] In addition, when performing process (1), such as Figure 1 As shown in one example, the process may include preparing a core substrate 10, which includes a support substrate 11 and a first metal layer 12 and a second metal layer 13 formed of a metal such as copper foil disposed on two surfaces of the support substrate 11. Examples of materials for the support substrate 11 include insulating substrates such as glass epoxy boards, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. Examples of materials for the first and second metal layers include copper foil with a carrier and the materials of the conductor layers described later.

[0114] In addition, such as Figure 2As shown in one example, the process of forming a through-hole 14 in the core substrate 10 may be included. The through-hole 14 can be formed, for example, by drilling, laser irradiation, plasma irradiation, etc. Specifically, the through-hole 14 can be formed by forming a through hole in the core substrate 10 using a drill bit or the like.

[0115] The through hole 14 can be formed using a commercially available drill bit. Examples of commercially available drill bits include the "ND-1S211" manufactured by Hitachi Via Machinery Co., Ltd.

[0116] After the through-hole 14 is formed on the core substrate 10, as Figure 3 As shown in one example, it may include: roughening the core substrate 10 and forming a plating layer 20 in the through hole 14, on the surface of the first metal layer 12, and on the surface of the second metal layer 13.

[0117] As described above, any roughening treatment, whether dry or wet, can be performed. Examples of dry roughening treatment include plasma treatment. Furthermore, examples of wet roughening treatment include a method that sequentially performs a swelling treatment using a swelling solution, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing solution.

[0118] The plating layer 20 can be formed by plating, and the steps for forming the plating layer 20 by plating are the same as those for forming the conductor layer in step (5) described later.

[0119] After preparing the core substrate 10, as follows Figure 4 As shown in one example, the through-hole 14 is filled with magnetic composition 30a. The filling can be performed, for example, by printing. Examples of printing methods include: printing magnetic composition 30a into the through-hole 14 via a squeegee, printing magnetic composition 30a via a cartridge, printing magnetic composition 30a by mask printing, roller coating, inkjet printing, etc.

[0120] <Process (2)> In step (2), after filling the through hole 14 with magnetic composition 30a, the magnetic composition 30a is thermo-cured, such as... Figure 5As shown in one example, a cured layer (magnetic layer) 30 is formed within the through-hole 14. The thermosetting conditions of the magnetic composition 30a vary depending on the composition or type of the magnetic composition 30a. The curing temperature is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. The curing time of the magnetic composition 30a is preferably 5 minutes or higher, more preferably 10 minutes or higher, even more preferably 15 minutes or higher, preferably 120 minutes or lower, more preferably 100 minutes or lower, and even more preferably 90 minutes or lower.

[0121] The degree of curing of the magnetic layer 30 in step (2) is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The degree of curing can be measured, for example, using a differential scanning calorimeter.

[0122] Before heat curing the magnetic composition 30a, a preheating treatment can be performed on the magnetic composition 30a at a temperature lower than the curing temperature. For example, before heat curing the magnetic composition 30a, the magnetic composition 30a can be preheated for a period of 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes) at a temperature of 50°C or higher and lower than 120°C (preferably 60°C or higher and lower than 110°C, more preferably 70°C or higher and lower than 100°C).

[0123] When step (3) is performed after step (2), heat treatment may be performed as needed to further improve the curing degree of the magnetic layer, etc., after step (2) and before step (3). The temperature in the aforementioned heat treatment shall be the curing temperature described above, preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, even more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 90 minutes or lower, more preferably 70 minutes or lower, even more preferably 60 minutes or lower.

[0124] Furthermore, if step (3) is performed before step (2), a preheating treatment can be performed before step (3) at a temperature lower than the curing temperature of the magnetic composition. The temperature in the aforementioned preheating treatment is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 90 minutes or less, more preferably 70 minutes or less, and even more preferably 60 minutes or less.

[0125] <Process (3)> In process (3), such as Figure 6 As shown in one example, excess magnetic layer 30 protruding from or attached to the core substrate 10 is removed by grinding, thereby achieving planarization. As a grinding method, a method capable of grinding excess magnetic layer 30 protruding from or attached to the core substrate 10 can be used. Examples of such grinding methods include polishing and belt grinding. Commercially available polishing apparatuses include the "NT-700IM" manufactured by Ishii Optoelectronics Co., Ltd.

[0126] The arithmetic mean roughness (Ra) of the polished surface of the magnetic layer (after thermosetting) is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion to the coating. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, and even more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0127] When step (3) is performed after step (2), heat treatment may be performed as needed to further improve the curing degree of the magnetic layer, etc., after step (2) and before step (3). The temperature in the aforementioned heat treatment shall be the curing temperature described above, preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, even more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 90 minutes or lower, more preferably 70 minutes or lower, even more preferably 60 minutes or lower.

[0128] Furthermore, if step (3) is performed before step (2), a preheating treatment can be performed before step (3) at a temperature lower than the curing temperature of the magnetic composition. The temperature in the aforementioned preheating treatment is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 90 minutes or less, more preferably 70 minutes or less, and even more preferably 60 minutes or less.

[0129] <Process (4)> In step (4), the surface ground in step (3) is roughened (except for contamination treatment). The steps and conditions of the roughening process are not particularly limited, and known steps and conditions commonly used in the manufacturing method of multilayer printed wiring boards can be adopted. As a roughening process, for example, the first magnetic layer 32 can be roughened by sequentially performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid.

[0130] There are no particular limitations on the swelling solution that can be used in the roughening process; examples include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Among the alkaline solutions used as swelling solutions, sodium hydroxide solutions and potassium hydroxide solutions are more preferred. Commercially available swelling solutions include, for example, "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by ATOTECH JAPAN.

[0131] There are no particular limitations on the swelling treatment using a swelling solution. For example, it can be performed by immersing the core substrate 20, on which the first magnetic layer 32 is disposed, in a swelling solution at 30°C to 90°C for 1 minute to 20 minutes. From the viewpoint of controlling the swelling of the resin constituting the first magnetic layer 32 at an appropriate level, it is preferable to immerse the first magnetic layer 32 in a swelling solution at 40°C to 80°C for 5 minutes to 15 minutes.

[0132] As an oxidant that can be used for roughening treatment, there are no particular limitations; examples include alkaline permanganate solutions obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidant such as an alkaline permanganate solution is preferably performed by immersing the first magnetic layer 32 in an oxidant solution heated to 60°C to 80°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Commercially available oxidants include, for example, alkaline permanganate solutions such as "Concentrate Compact P" and "Dosing solution Securiganth P" manufactured by Ammet Japan Co., Ltd.

[0133] The neutralizing solution used for neutralization treatment is preferably an acidic aqueous solution. Commercially available examples include "Reduction solution Securiganth P" manufactured by Ammet Japan Co., Ltd. Neutralization treatment using the neutralizing solution can be performed by immersing the roughened surface treated with the oxidizing agent solution in the neutralizing solution at a temperature of 30°C to 80°C for 5 to 30 minutes. From an operability perspective, it is preferable to immerse the first magnetic layer 32, which has undergone roughening treatment with the oxidizing agent solution, in a neutralizing solution at a temperature of 40°C to 70°C for 5 to 20 minutes.

[0134] The arithmetic mean roughness (Ra) of the roughening treatment of the magnetic layer, from the viewpoint of improving adhesion to the coating, is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 1000 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0135] <Process (5)> In process (5), such as Figure 7 As shown in one example, a conductor layer 40 is formed on the polished surface of the magnetic layer 30 and on the core substrate. Furthermore, after forming the conductor layer 40, as... Figure 8 As shown in one example, a portion of the conductor layer 40, the first metal layer 12, the second metal layer 13, and the plating layer 20 can be removed by etching or other processes to form a patterned conductor layer 41. Figure 7 In this process, conductor layers 40 are formed on both sides of the core substrate 10, but conductor layers 40 may also be formed on only one side of the core substrate 10.

[0136] Methods for forming the conductor layer include, for example, plating, sputtering, and vapor deposition, with plating being preferred. In a preferred embodiment, a patterned conductor layer with a desired wiring pattern is formed by plating the surface of a cured material using a suitable method such as a semi-additive or fully additive method. Materials for the conductor layer include, for example, single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium; and alloys of two or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. From the viewpoints of versatility, cost, and ease of patterning, it is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nickel-chromium alloys, copper-nickel alloys, or copper-titanium alloys; more preferably, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nickel-chromium alloys; and even more preferably, copper.

[0137] Here, an example of an embodiment in which a patterned conductor layer is formed on the polished surface of a cured material is described in detail. A seed layer is formed on the polished surface of the cured material using electroless plating. Next, an electroplated layer is formed on the formed seed layer using electroplating. If necessary, unwanted seed layers are removed using etching or other processes, thereby forming a conductor layer with the desired wiring pattern. After forming the conductor layer, annealing may be performed as needed to improve the peel strength, etc. Annealing can be performed, for example, by heating the circuit board at 150–200°C for 20–90 minutes.

[0138] From the perspective of thinning, the thickness of the patterned conductor layer is preferably below 70 μm, more preferably below 60 μm, further preferably below 50 μm, even more preferably below 40 μm, and particularly preferably below 30 μm, 20 μm, 15 μm, or 10 μm. The lower limit is preferably above 1 μm, more preferably above 3 μm, and even more preferably above 5 μm.

[0139] <Second Implementation> The circuit board of the second embodiment includes a magnetic layer formed using a cured magnetic composition. In the second embodiment, it is preferable to use a magnetic sheet to form the magnetic layer. Hereinafter, a second embodiment of the method for manufacturing the product substrate will be described. Explanations that overlap with those of the first embodiment will be omitted as appropriate.

[0140] The circuit board of the second embodiment can be manufactured, for example, by a manufacturing method comprising the following steps (A) to (D). This manufacturing method includes: (A) A process of laminating a magnetic sheet onto an inner substrate to form a magnetic layer by bonding a magnetic composition layer to an inner substrate. (B) The process of creating openings in the magnetic layer. (C) The process of roughening the surface of the magnetic layer, and (D) The process of forming a conductor layer on the polished surface of the magnetic layer.

[0141] The following is a detailed description of the above-mentioned processes (A) to (D) in the manufacture of the circuit board.

[0142] <Process (A)> Step (A) is a process of stacking a magnetic sheet onto an inner substrate by bonding a magnetic composition layer to an inner substrate to form a magnetic layer. As one embodiment of step (A), a magnetic sheet is stacked onto an inner substrate by bonding a magnetic composition layer to an inner substrate, and the magnetic composition layer is then thermosetting to form a magnetic layer.

[0143] In process (A), such as Figure 9As shown in one example, a magnetic sheet 310, comprising a support 330 and a magnetic composition layer 320a disposed on the support 330, is stacked on the inner substrate 200 in such a manner that the magnetic composition layer 320a is bonded to the inner substrate 200.

[0144] The inner layer substrate 200 is an insulating substrate. Examples of materials for the inner layer substrate 200 include insulating substrates such as glass epoxy boards, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate 200 can also be an inner circuit substrate with wiring and other components integrated into its thickness.

[0145] like Figure 9 As shown in one example, the inner substrate 200 has a first conductor layer 420 disposed on a first main surface 200a and an external terminal 240 disposed on a second main surface 200b. The first conductor layer 420 may include multiple wirings. In the example shown, only the wirings of the coil-shaped conductive structure 400 constituting the sensor element are shown. The external terminal 240 is a terminal for electrical connection to an external device, etc., not shown. The external terminal 240 may be configured as part of the conductor layer disposed on the second main surface 200b.

[0146] The conductor material that can form the first conductor layer 420 and the external terminal 240 is the same as the material of the conductor layer described in the “<process (5)>” column of the first embodiment.

[0147] The first conductor layer 420 and the external terminal 240 can be a single-layer structure or a multi-layer structure consisting of two or more single metal layers or alloy layers formed by different types of metals or alloys. Furthermore, the thickness of the first conductor layer 420 and the external terminal 240 is the same as that of the second conductor layer 440, which will be described later.

[0148] The linewidth (L) / spacing (S) ratio of the first conductor layer 420 and the outer terminal 240 is not particularly limited. From the viewpoint of reducing surface roughness and obtaining a magnetic layer with excellent smoothness, it is generally 900 / 900 μm or less, preferably 700 / 700 μm or less, more preferably 500 / 500 μm or less, further preferably 300 / 300 μm or less, and even more preferably 200 / 200 μm or less. The lower limit of the linewidth / spacing ratio is not particularly limited. From the viewpoint of ensuring good filling of the magnetic composition layer into the wiring space, it is preferably 1 / 1 μm or more.

[0149] The inner layer substrate 200 may have a plurality of through holes 220 extending through the inner layer substrate 200 from the first main surface 200a to the second main surface 200b. Through-hole wiring 220a is provided in the through holes 220. Through-hole wiring 220a electrically connects the first conductor layer 420 to the external terminal 240.

[0150] The bonding of the magnetic composition layer 320a to the inner substrate 200 can be achieved, for example, by heating and pressing the magnetic sheet 310 onto the inner substrate 200 from the support 330 side. Examples of components for heating and pressing the magnetic sheet 310 onto the inner substrate 200 (hereinafter also referred to as "heat-pressing component") include, for example, heated metal plates (stainless steel (SUS) end plates, etc.) or metal rollers (SUS rollers). It should be noted that it is preferable not to press the magnetic sheet 310 directly into contact with the heating and pressing component, but rather to press it through a sheet made of an elastic material such as heat-resistant rubber, so that the magnetic sheet 310 fully follows the surface irregularities of the inner substrate 200.

[0151] The temperature for heat pressing is preferably in the range of 80℃ to 160℃, more preferably 90℃ to 140℃, and even more preferably 100℃ to 120℃. The pressure for heat pressing is preferably in the range of 0.098MPa to 1.77MPa, more preferably 0.29MPa to 1.47MPa. The time for heat pressing is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. The bonding of the magnetic sheet to the inner substrate is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0152] The bonding of the magnetic composition layer 320a of the magnetic sheet 310 to the inner substrate 200 can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include, for example, the vacuum pressure laminator manufactured by Meiki Manufacturing Co., Ltd., and the vacuum applicator manufactured by Nikko-Materials Co., Ltd.

[0153] After the magnetic sheet 310 is bonded to the inner substrate 200, the heated pressing member is pressed under normal pressure (atmospheric pressure), for example, from the support side, thereby performing a smoothing process on the laminated magnetic sheet 310. The pressing conditions for the smoothing process can be set to the same conditions as the heated pressing conditions for the lamination described above. The smoothing process can be performed using a commercially available laminator. It should be noted that lamination and smoothing processes can be performed continuously using the aforementioned commercially available vacuum laminator.

[0154] After laminating a magnetic sheet onto an inner substrate, the magnetic composition layer is thermally cured to form a magnetic layer. For example... Figure 10As shown in one example, the magnetic composition layer 320a bonded to the inner substrate 200 is thermally cured to form the first magnetic layer 320.

[0155] The thermosetting conditions of the magnetic composition layer 320a vary depending on the composition or type of the magnetic composition. The curing temperature is preferably above 120°C, more preferably above 130°C, even more preferably above 150°C, preferably below 245°C, more preferably below 220°C, and even more preferably below 200°C. The curing time of the magnetic composition layer 320a is preferably above 5 minutes, more preferably above 10 minutes, even more preferably above 15 minutes, preferably below 120 minutes, more preferably below 100 minutes, and even more preferably below 90 minutes.

[0156] The support 330 can be removed between process (B) and process (A) after thermosetting, or it can be peeled off after process (B).

[0157] The arithmetic mean roughness (Ra) of the magnetic layer before roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion between the magnetic layer and the coating. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, and even more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0158] For process (A), instead of magnetic sheets, the magnetic composition can be coated onto the inner substrate using a die coater or similar tool and then thermally cured to form a magnetic layer.

[0159] <Process (B)> In process (B), such as Figure 11 As shown in one example, an opening is formed in the first magnetic layer 320 to create a via hole 360. The via hole 360 ​​serves as a path for electrically connecting the first conductor layer 420 to the second conductor layer 440, which will be described later. The formation of the via hole 360 ​​can be carried out using, for example, a drill bit, laser, plasma, etc., depending on the composition of the magnetic composition used in the formation of the magnetic layer. The size and shape of the hole can be appropriately determined according to the design of the printed circuit board.

[0160] <Process (C)> In step (C), the surface of the magnetic layer with the through hole is roughened. As described in the “<Step (4)>” section of the first embodiment, the roughening process in step (C) is as follows.

[0161] The arithmetic mean roughness (Ra) of the roughening treatment of the magnetic layer, from the viewpoint of improving adhesion to the coating, is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 1000 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0162] In process (C), polishing can be performed instead of roughening to remove excess magnetic layer protruding from or attached to the core substrate 10 and to achieve planarization. The polishing method is as described above.

[0163] <Process (D)> In process (D), such as Figure 12 As shown in one example, a second conductor layer 440 is formed on the first magnetic layer 320.

[0164] The conductor material that can form the second conductor layer 440 is the same as the material of the conductor layer described in the “<process (5)>” column of the first embodiment.

[0165] From the perspective of thinning, the thickness of the second conductor layer 440 is preferably less than 70 μm, more preferably less than 60 μm, further preferably less than 50 μm, even more preferably less than 40 μm, and particularly preferably less than 30 μm, less than 20 μm, less than 15 μm, or less than 10 μm. The lower limit is preferably more than 1 μm, more preferably more than 3 μm, and even more preferably more than 5 μm.

[0166] The second conductor layer 440 can be formed by plating. Preferably, the second conductor layer 440 is formed using a wet plating method, such as a semi-additive method or a fully additive method, which includes an electroless plating process, a mask patterning process, an electrolytic plating process, and a flash etching process. By forming the second conductor layer 440 using a wet plating method, it can be formed as a second conductor layer 440 containing the desired wiring pattern. It should be noted that this process allows the in-via wiring 360a to be formed simultaneously within the via 360.

[0167] For the first conductor layer 420 and the second conductor layer 440, for example, as described later. Figures 13-15As shown in one example, it can be configured as a spiral. In one example, one end of the central side of the spiral wiring portion of the second conductor layer 440 is electrically connected to one end of the central side of the spiral wiring portion of the first conductor layer 420 through the through-hole wiring 360a. The other end of the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the pad 420a of the first conductor layer 420 through the through-hole wiring 360a. Therefore, the other end of the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the external terminal 240 via the through-hole wiring 360a, the pad 420a, and the through-hole wiring 220a.

[0168] The coil-shaped conductive structure 400 is composed of a spiral wiring portion that is part of a first conductor layer 420, a spiral wiring portion that is part of a second conductor layer 440, and a through-hole wiring portion 360a that electrically connects the spiral wiring portion of the first conductor layer 420 and the spiral wiring portion of the second conductor layer 440.

[0169] Following step (D), a further step can be performed to form a magnetic layer on the conductor layer. Details are as follows... Figure 14 As shown in one example, the second magnetic layer 340 is formed on the first magnetic layer 320 on which the second conductor layer 440 and the through-hole wiring 360a are formed. The second magnetic layer can be formed using the same process as that already described.

[0170] [Sensor substrate] The sensor substrate includes the circuit substrate of the present invention. When such a sensor substrate includes a circuit substrate obtained by the manufacturing method of the circuit substrate of the first embodiment, at least a portion around the cured magnetic composition has a sensor pattern formed of a conductor. Such a sensor substrate can be, for example, the substrate described in Japanese Patent Application Publication No. 2016-197624.

[0171] Furthermore, in the case of a circuit board obtained by the manufacturing method of the circuit board according to the second embodiment, the sensor board has a magnetic layer and a conductive structure at least a portion of which is embedded in the magnetic layer, and includes a sensor element composed of the conductive structure and a portion of the magnetic layer extending along the thickness direction of the magnetic layer and surrounded by the conductive structure. Here, Figure 13 A schematic top view of a sensor substrate with built-in sensor elements, viewed from one side in its thickness direction. Figure 14 To indicate that in by Figure 13 The diagram shows a cut end face of the sensor substrate, indicated by the dotted line II-II. Figure 15 This is a schematic top view used to illustrate the structure of the first conductor layer in the sensor substrate.

[0172] like Figure 13 and Figure 14 As shown as an example, the circuit board 100 is a stacked wiring board having multiple magnetic layers (first magnetic layer 320, second magnetic layer 340) and multiple conductor layers (first conductor layer 420, second conductor layer 440), that is, having stacked magnetic layers and stacked conductor layers. In addition, the circuit board 100 includes an inner layer substrate 200.

[0173] according to Figure 14 The first magnetic layer 320 and the second magnetic layer 340 constitute a magnetic portion 300 that can be considered as an integral magnetic layer. Therefore, the coil-shaped conductive structure 400 is provided such that at least a portion of it is embedded in the magnetic portion 300. That is, in the circuit board 100 of this embodiment, the sensor element is composed of the coil-shaped conductive structure 400 and a core portion of the magnetic portion 300 that extends along the thickness direction of the magnetic portion 300 and is surrounded by the coil-shaped conductive structure 400.

[0174] like Figure 15 As illustrated in the figure, the first conductor layer 420 includes a spiral wiring portion for forming a coil-shaped conductive structure 400, and a rectangular pad 420a electrically connected to the wiring 220a within the via. In the example, the spiral wiring portion includes a straight portion, a curved portion bent at a right angle, and a detour portion meandering at the pad 420a. In the example, the spiral wiring portion of the first conductor layer 420 has a generally rectangular overall outline and is wound counterclockwise from the center outwards.

[0175] Similarly, a second conductor layer 440 is provided on the first magnetic layer 320. The second conductor layer 440 includes a spiral wiring portion for forming a coil-shaped conductive structure 400. Figure 13 or Figure 14 In the spiral wiring section, there are straight sections and curved sections bent at right angles. Figure 13 or Figure 14 In the second conductor layer 440, the spiral wiring portion has an overall outline that is roughly rectangular and is wound clockwise from the center to the outside.

[0176] Such a sensor substrate can be used as a wiring board for mounting electronic components such as semiconductor chips, or as a (multilayer) printed wiring board in which the wiring board is used as an inner layer substrate. Furthermore, it can be used as a chip sensor component formed by monolithically mounting the wiring board, or as a printed wiring board on which the chip sensor component is surface-mounted.

[0177] Furthermore, various types of semiconductor devices can be manufactured using the aforementioned wiring board. Semiconductor devices incorporating the wiring board are suitable for use in electrical products (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trams, ships, and aircraft). Example

[0178] The present invention will now be specifically described through embodiments, but the present invention is not limited to these embodiments. It should be noted that, unless otherwise expressly stated, in the following description, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0179] <Example 1: Preparation of Magnetic Composition 1> 15 parts by weight of epoxy resin a (“ZX-1059”, a mixture of bisphenol A and bisphenol F epoxy resins, manufactured by Nippon Steel Chemical Materials Co., Ltd.), 5 parts by weight of epoxy resin b (“ZX-1658GS”, liquid 1,4-glycidylcyclohexane, manufactured by Nippon Steel Chemical Materials Co., Ltd.), 1 part by weight of curing accelerator a (“2MZA-PW”, imidazole-based curing accelerator, manufactured by Shikoku Kasei Co., Ltd.), and 1 part by weight of magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, “KUAMET NC1”, D 50 40 parts by weight of magnetic powder (25μm), Fe-based nanocrystalline magnetic material, "ATFINE NC1", D 50 Mix 60 parts by mass of 3μm) to prepare magnetic composition 1.

[0180] <Example 2: Preparation of Magnetic Composition 2> In Example 1, magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMETNC1", D) was used. 50 40 parts by mass of 25μm were changed into magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET 6B2", D) 50 40 parts by weight of magnetic powder (25μm) were added to Fe-based nanocrystalline magnetic material, “ATFINE NC1”, D 50 60 parts by mass of 3μm were changed into magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F", D) 50 60 parts by weight (3μm); Apart from the above, the magnetic composition 2 was prepared in the same manner as in Example 1.

[0181] <Example 3: Preparation of Magnetic Composition 3> In Example 1, magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINENC1", D) was used. 50 60 parts by mass of 3μm were changed into magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F", D) 50 60 parts by weight (3μm); Apart from the above, the magnetic composition 3 was prepared in the same manner as in Example 1.

[0182] <Example 4: Preparation of Magnetic Composition 4> In Example 1, magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMETNC1", D) was used. 50 40 parts by mass of 25μm were changed into magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET 6B2", D) 50 40 parts by weight (25μm); Apart from the above, the magnetic composition 4 was prepared in the same manner as in Example 1.

[0183] <Example 5: Preparation of Magnetic Composition 5> 1.5 parts by weight of epoxy resin a (“ZX-1059”, a mixture of bisphenol A and bisphenol F epoxy resins, manufactured by Nippon Steel Chemical Materials Co., Ltd.), 0.5 parts by weight of epoxy resin b (“ZX-1658GS”, liquid 1,4-glycidylcyclohexane, manufactured by Nippon Steel Chemical Materials Co., Ltd.), 0.1 parts by weight of curing accelerator a (“2MZA-PW”, imidazole-based curing accelerator, manufactured by Shikoku Chemical Co., Ltd.), and 0.5 parts by weight of magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, “KUAMET6B2”, D... 50 30 parts by weight of magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F"), D (25μm) 50 Mix 70 parts by weight of 3μm to prepare magnetic composition 5.

[0184] <Example 6: Preparation of Magnetic Composition 6> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 30 parts by mass to 25 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 The amount of 3μm was changed from 70 parts by mass to 75 parts by mass; Apart from the above, the magnetic composition 6 was prepared in the same manner as in Example 5.

[0185] <Example 7: Preparation of Magnetic Composition 7> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of 25μm was changed from 30 parts by mass to 40 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 The amount of 3μm was changed from 70 parts by mass to 60 parts by mass; Apart from the above, the magnetic composition 7 was prepared in the same manner as in Example 5.

[0186] <Example 8: Preparation of Magnetic Composition 8> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 30 parts by mass to 50 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 The amount of 3μm was changed from 70 parts by mass to 50 parts by mass; Apart from the above, the magnetic composition 8 was prepared in the same manner as in Example 5.

[0187] <Example 9: Preparation of Magnetic Composition 9> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 30 parts by mass to 80 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 70 parts by mass of 3μm were changed into magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC1", D) 50 20 parts by weight (25μm); Apart from the above, the magnetic composition 9 was prepared in the same manner as in Example 5.

[0188] <Example 10: Preparation of Magnetic Composition 10> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of 25μm was changed from 30 parts by mass to 45 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 70 parts by mass of 3μm were changed into magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC1", D) 50 55 parts by weight (25μm); Apart from the above, the magnetic composition 10 was prepared in the same manner as in Example 5.

[0189] <Comparative Example 1: Preparation of Magnetic Composition 11> In Example 1, magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMETNC1", D) was used. 50 The amount of (25μm) was changed from 40 parts by mass to 100 parts by mass. Non-magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINE NC1", D) 50 60 parts by weight (3μm); Apart from the above, the magnetic composition 11 was prepared in the same manner as in Example 1.

[0190] <Comparative Example 2: Preparation of Magnetic Composition 12> In Example 1, magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINENC1", D) was used. 50 The amount of 3μm was changed from 60 parts by mass to 100 parts by mass. Non-magnetic powder a (EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMETNC1", D) 50 40 parts by weight (25μm); Apart from the above, the magnetic composition 12 was prepared in the same manner as in Example 1.

[0191] <Comparative Example 3: Preparation of Magnetic Composition 13> In Example 2, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 40 parts by mass to 100 parts by mass. Non-magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F", D) 50 60 parts by weight (3μm); Apart from the above, the magnetic composition 13 was prepared in the same manner as in Example 2.

[0192] <Comparative Example 4: Preparation of Magnetic Composition 14> In Example 2, magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 The amount of 3μm was changed from 60 parts by mass to 100 parts by mass. Non-magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET 6B2", D) 50 40 parts by weight (25μm); Apart from the above, the magnetic composition 14 was prepared in the same manner as in Example 2.

[0193] <Comparative Example 5: Preparation of Magnetic Composition 15> In Example 2, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 40 parts by mass to 60 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 The amount of 3μm was changed from 60 parts by mass to 40 parts by mass; Apart from the above, the magnetic composition 15 was prepared in the same manner as in Example 2.

[0194] <Comparative Example 6: Preparation of Magnetic Composition 16> In Example 1, magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMETNC1", D) was used. 50 The amount of (25μm) was changed from 40 parts by mass to 60 parts by mass. The magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINE NC1", D) 50The amount of 3μm was changed from 60 parts by mass to 40 parts by mass; Apart from the above, the magnetic composition 16 was prepared in the same manner as in Example 1.

[0195] <Comparative Example 7: Preparation of Magnetic Composition 17> In Example 5, magnetic powder b (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET6B2") was used. 50 The amount of (25μm) was changed from 30 parts by mass to 40 parts by mass. The magnetic powder d (manufactured by EPSON ATMIX, Fe-based amorphous magnetic material, "AW02-08PF3F") was used. 50 70 parts by mass of 3μm were changed into magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC1", D) 50 60 parts by weight (25μm); Apart from the above, the magnetic composition 17 was prepared in the same manner as in Example 5.

[0196] <(A) Determination of particle size distribution of components> Magnetic powder was dispersed in pure water using ultrasound to prepare a sample for testing. For the sample, a laser diffraction scattering particle size distribution analyzer (MicrotracBEL "MT3000II") was used to determine the D... 10 D 50 and D 90 .

[0197] <Determination of relative permeability and magnetic loss> As a support, a polyethylene terephthalate (PET) film (Lintec Corporation, "PET501010", 50 μm thick) treated with a silicone-based release agent was prepared. Magnetic compositions 1 to 17 were uniformly coated onto the release surface of the PET film using a doctor blade to achieve a dried magnetic composition layer thickness of 100 μm, resulting in a magnetic sheet. The magnetic composition layer was thermocured by heating the obtained magnetic sheet at 190°C for 90 minutes. The cured sheet was then peeled off to obtain a sheet-like product. The cured product was cut into test pieces with a width of 5 mm and a length of 18 mm as evaluation samples. For these evaluation samples, the relative permeability (μ') and its imaginary component (μ") were measured using the 3-turn coil method at a room temperature of 23°C (Agilent Technologies, "HP8362B"). Magnetic loss was calculated from μ" / μ'.

[0198] The relative permeability is evaluated according to the following criteria; 〇: Relative permeability of 17 or higher △: Relative permeability is 15 or higher and less than 17 ×: Relative permeability is less than 15.

[0199] In addition, magnetic loss is evaluated according to the following criteria; 〇: Magnetic loss is less than 0.05 △: Magnetic loss is greater than 0.05 and less than 0.08. ×: Magnetic loss is above 0.08.

[0200] [Table 1] (Table 1) [Table 2] (Table 2)

[0201] It can be known that component D of (A) 10 D 50 and D 90 Examples 1 to 10, which are within the specified range, show improved relative permeability and reduced magnetic loss compared to Comparative Examples 1 to 7.

[0202] [Explanation of Symbols] 10-core substrate 11 Support base plate 12 First metal layer 13 Second metal layer 14 Through holes 20 coatings 30a Magnetic Composition 30 magnetic layers 40 Conductor Layer 41 Patterned Conductor Layer 100 Circuit Board 200 Inner Layer Substrate 200a First Main Surface 200b Second Main Surface 220 through hole 220a Through-hole Wiring 240 external terminals 300 Magnetic Section 310 Magnetic Sheet 320a Magnetic Composition Layer 320 First Insulation Layer 330 Support 340 Second Insulation Layer 360 holes 360a through-hole wiring 400 coil-shaped conductive structure 420 First Conductor Layer 420a pad 440 Second conductor layer.

Claims

1. A magnetic composition comprising (A) magnetic powder and (B) a binder resin, in, (A) 10% of the particle size distribution of the component (D) 10 The particle size is 1.7 μm or larger and 2.6 μm or smaller, with 50% of the particles having a diameter (D). 50 The particle size is 3.6 μm or larger and 6.0 μm or smaller, and 90% of the particle size (D) is within the acceptable range. 90 The value is above 25.0 μm and below 51.0 μm. (B) Components include liquid epoxy resin. The liquid epoxy resin accounts for more than 1% and less than 30% by mass relative to component (A) per 100% by mass. (A) The composition contains two or more magnetic powders with different average particle sizes. When the average particle size of one magnetic powder is set as a1 and the average particle size of the other magnetic powder is set as a2, a1 / a2 is greater than 5 and less than 25 / 3, where a1>a2.

2. The magnetic composition according to claim 1, wherein, (A) 10% of the particle size distribution of the component (D) 10 The value is above 1.9μm.

3. The magnetic composition according to claim 1, wherein, (A) 10% of the particle size distribution of the component (D) 10 The size is below 2.4 μm.

4. The magnetic composition according to claim 1, wherein, (A) 50% of the particle size distribution of the component (D) 50 The size is above 5.0 μm.

5. The magnetic composition according to claim 1, wherein, (A) 90% of the particle size in the particle size distribution of the component (D) 90 The value is above 27.0 μm.

6. The magnetic composition according to claim 1, wherein, (A) 90% of the particle size in the particle size distribution of the component (D) 90 The value is below 49.0 μm.

7. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (A) is 60% by mass or more.

8. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (A) is 80% by mass or more.

9. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (A) is 99.5% by mass or less.

10. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (A) is 98% by mass or less.

11. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (B) is 0.1% by mass or more.

12. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (B) is 1% by mass or more.

13. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (B) is less than 30% by mass.

14. The magnetic composition according to claim 1, wherein, When the non-volatile component in the magnetic composition is set to 100% by mass, the content of component (B) is less than 20% by mass.

15. The magnetic composition according to claim 1, wherein, (A) The component is soft magnetic powder.

16. The magnetic composition according to claim 1, wherein, (A) The composition is any magnetic material among nanocrystalline magnetic materials and amorphous magnetic materials.

17. The magnetic composition according to claim 1, wherein, (A) The composition contains iron alloy metal powder.

18. The magnetic composition according to claim 1, wherein, (A) Any magnetic material whose composition is Fe-based nanocrystalline magnetic material or Fe-based amorphous magnetic material.

19. The magnetic composition according to claim 1, used to form a sensor element.

20. The magnetic composition according to claim 1, wherein it is in the form of a paste.

21. The magnetic composition according to claim 1, used for filling through holes.

22. A magnetic sheet comprising: Support body, and A magnetic composition layer formed of the magnetic composition according to any one of claims 1 to 21 is disposed on the support.

23. A circuit board comprising a magnetic layer, the magnetic layer being a cured product of the magnetic composition according to any one of claims 1 to 21.

24. A circuit board comprising: Substrate with through holes, and The cured product of the magnetic composition according to any one of claims 1 to 21 that fills the through hole.

25. A sensor substrate comprising the circuit substrate of claim 23 or 24.

Images