CN113470918A

CN113470918A - Magnetic composition

Info

Publication number: CN113470918A
Application number: CN202110326114.5A
Authority: CN
Inventors: 萩原千寻; 大浦一郎; 大山秀树
Original assignee: Ajinomoto Co Inc
Current assignee: Ajinomoto Co Inc
Priority date: 2020-03-30
Filing date: 2021-03-26
Publication date: 2021-10-01
Also published as: JP2021158316A; TW202138591A; JP2023164858A

Abstract

The invention provides a magnetic composition which can obtain a cured product with improved relative permeability and reduced magnetic loss, and a magnetic sheet, a circuit board and an inductor substrate which are obtained by using the magnetic composition. The solution of the present invention is a magnetic composition comprising (A) a magnetic powder and (B) a binder resin, wherein 10% of the particle diameter (D) in the particle diameter distribution of the component (A)₁₀) Has a particle diameter (D) of 50% of 1.7-2.6 μm₅₀) Is 3.6 μm or more and12.0 μm or less and 90% particle diameter (D)₉₀) Is 25.0 to 51.0 μm in diameter.

Description

Magnetic composition

Technical Field

The present invention relates to a magnetic composition, and a magnetic sheet, a circuit board, and an inductor board obtained using the magnetic composition.

Background

A magnetic layer containing magnetic powder such as an inductor member may be provided on a circuit board such as a printed wiring board. As the magnetic powder contained in the magnetic layer, for example, patent document 1 describes a silicon oxide coated soft magnetic powder in which a soft magnetic powder is surface-treated with silicon oxide in order to suppress a reduction in magnetic loss.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2019-143241.

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, for further improvement in performance of inductor components, a technique capable of forming a magnetic layer having low magnetic loss has been demanded. Therefore, the present inventors have studied the relative permeability and the magnetic loss of the magnetic layer, and as a result, have found that: if the relative permeability is to be increased, the magnetic loss increases, and if the magnetic loss is to be decreased, the relative permeability decreases, and there is a trade-off relationship between increasing the relative permeability and decreasing the magnetic loss.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic composition that can provide a cured product having improved relative permeability and reduced magnetic loss, and a magnetic sheet, a circuit board, and an inductor board obtained using the magnetic composition.

Technical scheme for solving technical problem

The present inventors have made extensive studies and, as a result, have found that: the present inventors have found that a trade-off relationship between relative magnetic permeability and magnetic loss can be solved by including a magnetic powder having a predetermined particle size distribution in a magnetic composition, and have completed the present invention.

That is, the present invention includes the following;

[1] a magnetic composition comprising (A) a magnetic powder and (B) a binder resin,

wherein the component (A) has a particle diameter (D) of 10% in the particle diameter distribution₁₀) Has a particle diameter (D) of 50% of 1.7-2.6 μm₅₀) Has a particle diameter (D) of 3.6-12.0 μm and 90%₉₀) 25.0 to 51.0 [ mu ] m inclusive;

[2] the magnetic composition according to [1], wherein the component (A) is a soft magnetic powder;

[3] the magnetic composition according to [1] or [2], wherein the component (A) is any of a nanocrystalline magnetic material and an amorphous magnetic material;

[4] the magnetic composition according to any one of [1] to [3], wherein the component (A) contains an iron alloy-based metal powder;

[5] the magnetic composition according to any one of [1] to [4], wherein the component (A) is any one of an Fe-based nanocrystalline magnetic material and an Fe-based amorphous magnetic material;

[6] the magnetic composition according to any one of [1] to [5], which is used for forming an inductor element;

[7] the magnetic composition according to any one of [1] to [6], which is in the form of a paste;

[8] the magnetic composition according to any one of [1] to [7], which is used for filling a through-hole;

[9] a magnetic sheet, comprising:

a support, and

a magnetic composition layer formed of the magnetic composition according to any one of [1] to [8] provided on the support;

[10] a circuit board comprising a magnetic layer which is a cured product of the magnetic composition according to any one of [1] to [8 ];

[11] a circuit board includes:

a substrate having a through-hole, and

a cured product of the magnetic composition according to any one of [1] to [8] filled in the through-hole;

[12] an inductor substrate comprising the circuit substrate of [10] or [11 ].

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a magnetic composition capable of providing a cured product having improved relative permeability and reduced magnetic loss, and a magnetic sheet, a circuit board, and an inductor board obtained using the magnetic composition can be provided.

Brief description of the drawings

Fig. 1 is a schematic cross-sectional view of a core substrate as an example of a method of manufacturing a circuit substrate of a first embodiment;

fig. 2 is a schematic cross-sectional view of a core substrate having a through-hole formed therein as an example of a method of manufacturing a circuit substrate according to a first embodiment;

fig. 3 is a schematic cross-sectional view showing a form of a core substrate in which a plating layer is formed in a through-hole as an example of the method of manufacturing a circuit substrate according to the first embodiment;

fig. 4 is a schematic cross-sectional view showing a form of a core substrate in which a magnetic composition is filled in a through-hole as an example of the method of manufacturing a circuit substrate according to the first embodiment;

fig. 5 is a schematic cross-sectional view showing a form of a core substrate after thermosetting a filled magnetic composition as an example of a method of manufacturing a circuit substrate according to the first embodiment;

fig. 6 is a schematic cross-sectional view showing a form of a core substrate after polishing a cured product, which is an example of the method of manufacturing a circuit substrate according to the first embodiment;

fig. 7 is a schematic cross-sectional view showing a form of a core substrate in which a conductor layer is formed on a polished surface, which is an example of the method of manufacturing a circuit substrate according to the first embodiment;

fig. 8 is a schematic cross-sectional view showing a form of a core substrate on which a pattern conductor layer is formed as an example of the method of manufacturing a circuit substrate according to the first embodiment;

fig. 9 is a schematic cross-sectional view for explaining a step (a) included in an example of the method of manufacturing a circuit board according to the second embodiment;

fig. 10 is a schematic cross-sectional view for explaining a step (a) included in an example of the method of manufacturing a circuit board according to the second embodiment;

fig. 11 is a schematic cross-sectional view for explaining a step (B) included in an example of the method of manufacturing a circuit board according to the second embodiment;

fig. 12 is a schematic cross-sectional view for explaining a step (D) included in an example of the method of manufacturing a circuit board according to the second embodiment;

fig. 13 is a schematic plan view of an inductor component including a circuit board obtained by the method for manufacturing a circuit board according to the second embodiment, as an example, as viewed from one side in the thickness direction thereof;

fig. 14 is a schematic view showing a cut end face of a sensor part including a circuit board obtained by the method for manufacturing a circuit board according to the second embodiment, cut at a position indicated by a chain line II-II shown in fig. 13 as an example;

fig. 15 is a schematic plan view for explaining a configuration of a first conductor layer in an inductor component including a circuit board obtained by the method for manufacturing a circuit board according to the second embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are only for the purpose of illustrating the shape, size, and arrangement of the constituent elements in a simplified manner to the extent that the invention can be understood. The present invention is not limited to the following embodiments, and each constituent element may be appropriately modified. Further, the configurations described in the embodiments of the present invention are not limited to being manufactured or used only by the configurations illustrated in the drawings.

[ magnetic composition ]

The magnetic composition of the present invention comprises (A) a magnetic powder and (B) a binder resin, wherein the particle diameter (D) of 10% in the particle diameter distribution of the component (A)₁₀) Has a particle diameter (D) of 50% of 1.7-2.6 μm₅₀) Has a particle diameter (D) of 3.6-12.0 μm and 90%₉₀) Is 25.0 to 51.0 μm in diameter. In the present invention, by containing a magnetic powder having a predetermined particle size distribution in a magnetic composition, it is possible to simultaneously improve the relative permeability and reduce the magnetic loss of a cured product of the magnetic composition.

The magnetic composition may further contain (C) a curing accelerator, (D) a dispersant, and (E) other additives, as required. Hereinafter, each component contained in the magnetic composition of the present invention will be described in detail.

Magnetic powder (A)

The magnetic composition contains a magnetic powder as component (A)And having the following particle size distribution: (A) 10% particle diameter (D) in the particle diameter distribution of component (A)₁₀) Has a particle diameter (D) of 50% of 1.7-2.6 μm₅₀) Has a particle diameter (D) of 3.6-12.0 μm and 90%₉₀) Is 25.0 to 51.0 μm in diameter. The particle size distribution indicates the particle size distribution of the entire magnetic powder (a) contained in the magnetic composition. By containing the component (a) in the magnetic composition, the relative permeability of the cured product thereof can be improved and the magnetic loss can be reduced at the same time.

(A) The particle size distribution of the magnetic powder can be measured by a laser diffraction scattering method based on Mie scattering theory. Specifically, the particle size distribution of the magnetic powder was prepared on a volume basis by a laser diffraction scattering particle size distribution measuring apparatus, and the 10% particle size (D) was measured₁₀) 50% particle diameter (D)₅₀) And a particle diameter (D) of 90%₉₀). As the measurement sample, a sample obtained by dispersing magnetic powder in pure water by ultrasonic waves can be preferably used. As the laser diffraction scattering type particle size distribution measuring device, there can be used "MT 3000 II" manufactured by MicrotracBEL, "LA-960" manufactured by horiba, Ltd., SALD-2200 "manufactured by Shimadzu, Ltd.

10% particle size (D) in the particle size distribution₁₀) The particle size refers to a particle size at which the cumulative amount of volumes accumulated from the side where the particle size is small becomes 10% in the particle size distribution as a result of measurement of the particle size distribution by the above-described method. 50% particle diameter (D)₅₀) The particle size refers to a particle size at which the cumulative amount of volumes accumulated from the side where the particle size is small becomes 50% in the particle size distribution as a result of measurement of the particle size distribution by the above-described method. Further, 90% particle diameter (D)₉₀) The particle size refers to a particle size at which the cumulative amount of volumes accumulated from the side where the particle size is small becomes 90% in the particle size distribution as a result of measurement of the particle size distribution by the above-described method. Here, the average particle diameter of the magnetic powder (A) means 50% particle diameter (D)₅₀) The particle size of (1). Hereinafter, the particle diameter (D) of 10% may be₁₀) Referred to as D₁₀The particle diameter (D) is 50%₅₀) Referred to as D₅₀And a particle diameter (D) of 90%₉₀) Referred to as D₉₀。

As D in the particle size distribution₁₀From the viewpoint of achieving both an improvement in the relative permeability and a reduction in the magnetic loss of a cured product of the magnetic composition, the thickness is 1.7 μm or more, preferably 1.8 μm or more, more preferably 1.9 μm or more. The upper limit is 2.6 μm or less, preferably 2.5 μm or less, more preferably 2.4 μm or less.

As D in the particle size distribution₅₀From the viewpoint of achieving both an improvement in the relative permeability and a reduction in the magnetic loss of a cured product of the magnetic composition, the thickness is 3.6 μm or more, preferably 4.0 μm or more, more preferably 5.0 μm or more. The upper limit is 12.0 μm or less, preferably 11.0 μm or less, more preferably 10.0 μm or less.

As D in the particle size distribution₉₀The relative permeability of the cured product of the magnetic composition is 25.0 μm or more, preferably 26.0 μm or more, more preferably 27.0 μm or more, from the viewpoint of achieving both an improvement in the relative permeability and a reduction in the magnetic loss. The upper limit is 51.0 μm or less, preferably 50.0 μm or less, more preferably 49.0 μm or less.

As D₅₀-D₁₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 1.0 μm or more, more preferably 1.1 μm or more, and still more preferably 1.2 μm or more. The upper limit is preferably 10.3 μm or less, more preferably 10.2 μm or less, further preferably 10.1 μm or less.

As D₉₀-D₁₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 22.4 μm or more, more preferably 22.5 μm or more, and still more preferably 22.6 μm or more. The upper limit is preferably 49.3 μm or less, more preferably 49.2 μm or less, and still more preferably 49.1 μm or less.

As D₉₀-D₅₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 13 μm or more, more preferably 14 μm or more, and still more preferably 15 μm or more. The upper limit is preferably 47.4 μm or less, more preferably 47.0 μm or less, and still more preferably 46.0 μm or less.

As D₉₀/D₅₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 14.17 or less, more preferably 12.75 or less, and still more preferably 10.20 or less. Lower limit is relativelyPreferably 2.08 or more, more preferably 2.27 or more, and further more preferably 2.50 or more.

As D₉₀/D₁₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 30.0 or less, more preferably 28.3 or less, and further more preferably 26.8 or less. The lower limit is preferably 9.62 or more, more preferably 10 or more, and still more preferably 10.4 or more.

As D₅₀/D₁₀From the viewpoint of remarkably obtaining the effect of the present invention, it is preferably 7.06 or less, more preferably 6.67 or less, and still more preferably 6.32 or less. The lower limit is preferably 1.38 or more, more preferably 1.44 or more, further preferably 1.89 or more.

The magnetic powder (a) may be either a soft magnetic powder or a hard magnetic powder, but is preferably a soft magnetic powder from the viewpoint of suppressing localization (maldistribution) of the magnetic powder.

The magnetic powder (a) is preferably any of a nanocrystalline magnetic material and an amorphous magnetic material from the viewpoint of achieving both improvement in the relative permeability and reduction in the magnetic loss of a cured product of the magnetic composition, and more preferably a nanocrystalline magnetic material from the viewpoint of reducing the magnetic loss by reducing the magnetic anisotropy of the crystal. In the present specification, the nanocrystalline magnetic material is a magnetic material containing crystal grains, and means a magnetic material in which the grain size of the crystal grains of the magnetic powder includes 100nm or less, and preferably the maximum grain size of the crystal grains is 100nm or less. In general, the magnetic powder (a) contains a plurality of crystal grains in 1 particle, and the particle may be a polycrystal. The size of the crystal grains can be observed by TEM (transmission electron microscope), for example. The nanocrystalline magnetic material contains crystal grains, and therefore can generally exhibit a peak showing crystallinity (crystalline property) in an X-ray diffraction pattern. Further, the amorphous magnetic material is an amorphous magnetic material, which means a material that does not show a specific peak showing crystallinity in an X-ray diffraction pattern. In general, an X-ray diffraction pattern of an amorphous magnetic material shows a broad pattern which is not a peak showing crystallinity. When the magnetic powder (a) is any of a nanocrystalline magnetic material and an amorphous magnetic material, the magnetic flux density is high, and as a result, it is considered that both improvement in the relative permeability and reduction in the magnetic loss can be effectively achieved.

Examples of the magnetic powder (A) include iron alloy metal powders (Fe-based metal powders) such as Fe-Si alloy powders, Fe-Si-Al alloy powders, Fe-Cr-Si alloy powders, Fe-Ni-Cr alloy powders, Fe-Cr-Al alloy powders, Fe-Ni-Mo-Cu alloy powders, Fe-Co alloy powders, and Fe-Ni-Co alloy powders.

Among them, the magnetic powder (a) is preferably an iron alloy-based metal powder from the viewpoint of remarkably obtaining the effect of the present invention. The iron alloy-based metal powder preferably contains: an iron alloy-based metal powder containing at least one element selected from the group consisting of Fe, Si, Cr, Al, Ni, and Co, more preferably: an iron alloy metal powder containing Fe, Si and Cr. Further, it is more preferable that the magnetic material is any of a nanocrystalline magnetic material and an amorphous magnetic material containing at least one element selected from Fe, Si, Cr, Al, Ni, and Co, and it is further more preferable that the magnetic material is any of a nanocrystalline magnetic material and an amorphous magnetic material containing Fe, Si, Cr, a Fe-based nanocrystalline magnetic material and a Fe-based amorphous magnetic material, and it is further more preferable that the magnetic material is a Fe-based nanocrystalline magnetic material. Here, the Fe group means that it contains an Fe atom.

(A) The magnetic powder can be adjusted to a predetermined particle size distribution by, for example, classification. The particle size distribution described above indicates the particle size distribution of the entire component (a) contained in the magnetic composition. Therefore, the component (a) obtained by mixing two or more kinds of magnetic powders may be adjusted to have a predetermined particle size distribution, and for example, a plurality of kinds of magnetic powders having no predetermined particle size distribution may be mixed to have a predetermined particle size distribution as the whole component (a).

(A) One kind of magnetic powder may be used alone, or two or more kinds may be used in combination, but from the viewpoint of remarkably obtaining the effect of the present invention, it is preferable to use two or more kinds of magnetic powder in combination, and it is more preferable to use two or more kinds of magnetic powder having different average particle diameters in combination. In one embodiment, when two magnetic powders having different average particle diameters are used in combination, the average particle diameter of one of the magnetic powders is preferably 0.01 μm or more, more preferably 0.5 μm or more, and still more preferably 1 μm or more. Further, it is preferably less than 10 μm, more preferably 9 μm or less, further preferably 8 μm or less. The average particle diameter of the other magnetic powder is preferably 10 μm or more, more preferably 13 μm or more, and still more preferably 15 μm or more. Further, it is preferably 30 μm or less, more preferably 25 μm or less, further preferably 23 μm or less.

When two or more magnetic powders having different average particle diameters are used in combination, when the average particle diameter of one magnetic powder is a1 and the average particle diameter of the other magnetic powder is a2, a1/a2 is preferably 1 or more, more preferably 3 or more, further preferably 5 or more, preferably 15 or less, more preferably 10 or less, and further more preferably 8 or less. Wherein a1 is more than a 2. By adjusting a1/a2 so as to be within the range, the effects of the present invention can be remarkably obtained.

As the magnetic powder (a), commercially available products may be used, or two or more kinds may be used in combination. Specific examples of commercially available magnetic powder that can be used include "kuumet NC 1" and "ATFINE NC 1" (nanocrystalline magnetic material) manufactured by EPSON ATMIX; "KUAMET 6B 2" and "AW 02-08PF 3F" (amorphous magnetic materials) manufactured by EPSON ATMIX.

(A) The magnetic powder is preferably spherical. The value (aspect ratio) obtained by dividing the length of the major axis of the magnetic powder by the length of the minor axis is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2 or less, still more preferably more than 1, and still more preferably 1.05 or more. In general, when the magnetic powder is in a non-spherical flat shape, the relative permeability is easily improved, but in the present invention, it is preferable to use a spherical magnetic powder from the viewpoint of reducing the magnetic loss and from the viewpoint of obtaining a magnetic composition having a good viscosity.

From the viewpoint of improving the relative permeability, the specific surface area of the (A) magnetic powder is preferably 0.05m²More than g, preferably 0.1m²More preferably 0.3m or more in terms of a molar ratio of the compound to the metal²More than g. Further, it is preferably 15m²A value of less than g, preferably 12m²A total of 10m or less²The ratio of the carbon atoms to the carbon atoms is less than g. (A) The specific surface area of the magnetic powder can be measured by the BET method.

From the viewpoint of improving the relative permeability and reducing the magnetic loss, the content (volume%) of the (a) magnetic powder is preferably 10 volume% or more, more preferably 20 volume% or more, and still more preferably 30 volume% or more, assuming that the nonvolatile component in the magnetic composition is 100 volume%. Further, it is preferably 95% by volume or less, more preferably 90% by volume or less, and still more preferably 80% by volume or less.

The content (% by mass) of the (a) magnetic powder is preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more, with respect to 100% by mass of nonvolatile components in the magnetic composition, from the viewpoint of improving the relative permeability and reducing the magnetic loss. Further, it is preferably 99.5% by mass or less, more preferably 99% by mass or less, and still more preferably 98% by mass or less. In the present invention, the content of each component in the magnetic composition is a value when the nonvolatile component in the magnetic composition is 100 mass%, unless otherwise specified.

(B) Binder resin

The magnetic composition contains (B) a binder resin as the component (B). Examples of the binder resin (B) include: thermosetting resins such as epoxy resins, phenol resins (phenol resins), naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins; and thermoplastic resins such as phenoxy resins, acrylic resins, polyvinyl acetal resins, butyral resins, polyimide resins, polyamideimide resins, polyethersulfone resins, and polysulfone resins. (B) The component (b) may contain a thermosetting resin, a thermoplastic resin, or a combination thereof. (B) The binder resin is preferably a thermosetting resin contained in the insulating layer of the wiring board, and among them, an epoxy resin is preferred. (B) The binder resin may be used alone or in combination of two or more. Hereinafter, each resin will be described.

Here, components that react with an epoxy resin to cure a magnetic composition, such as a phenol resin (phenol resin), a naphthol resin, a benzoxazine resin, an active ester resin, a cyanate resin, a carbodiimide resin, an amine resin, and an acid anhydride resin, are sometimes collectively referred to as a "curing agent".

Thermosetting resins

Examples of the epoxy resin as the thermosetting resin include: epoxy resins of the glycidoxy (glycidyl) type; bisphenol a type epoxy resin; bisphenol F type epoxy resins; bisphenol S type epoxy resin; bisphenol AF type epoxy resin; dicyclopentadiene type epoxy resins; a trisphenol type epoxy resin; phenol novolac (phenol novolac) type epoxy resins; t-butyl-catechol-type epoxy resin; epoxy resins having a condensed ring structure such as naphthol novolac (naphthol novolac) type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, and the like; glycidyl amine type epoxy resins; glycidyl ester type epoxy resins; cresol novolac (cresol novolac) type epoxy resins; biphenyl type epoxy resin; linear aliphatic epoxy resin; an epoxy resin having a butadiene structure; a cycloaliphatic epoxy resin; a heterocyclic epoxy resin; epoxy resin containing spiro ring; cyclohexane dimethanol type epoxy resins; a trimethylol type epoxy resin; tetraphenylethane type epoxy resins, and the like. The epoxy resin may be used alone or in combination of two or more. The epoxy resin is preferably at least one selected from the group consisting of bisphenol A type epoxy resins and bisphenol F type epoxy resins.

The epoxy resin is preferably an epoxy resin containing 2 or more epoxy groups in 1 molecule. Further, the epoxy resin preferably has an aromatic structure, and in the case where two or more epoxy resins are used, at least one of the epoxy resins preferably has an aromatic structure. Aromatic structures are chemical structures generally defined as aromatic and include polycyclic aromatic and aromatic heterocycles. The proportion of the epoxy resin having 2 or more epoxy groups in 1 molecule is preferably 50% by mass or more, more preferably 60% by mass or more, particularly preferably 70% by mass or more, based on 100% by mass of the nonvolatile content of the epoxy resin.

The epoxy resin includes an epoxy resin that is liquid at a temperature of 25 ℃ (hereinafter, sometimes referred to as a "liquid epoxy resin") and an epoxy resin that is solid at a temperature of 25 ℃ (hereinafter, sometimes referred to as a "solid epoxy resin"). When the epoxy resin is contained as the component (B), the epoxy resin may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. Among them, the epoxy resin is preferably a liquid epoxy resin alone from the viewpoint of reducing the viscosity of the resin composition.

The liquid epoxy resin is preferably a glycidoxy (glycidyl) type epoxy resin, a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AF type epoxy resin, a naphthalene type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, a phenol novolac type epoxy resin, an alicyclic epoxy resin having an ester skeleton, a cyclohexane dimethanol type epoxy resin, or an epoxy resin having a butadiene structure, and more preferably a glycidoxy (glycidyl) type epoxy resin, a bisphenol a type epoxy resin, or a bisphenol F type epoxy resin. Specific examples of the liquid epoxy resin include "HP 4032", "HP 4032D" and "HP 4032 SS" (naphthalene type epoxy resin) manufactured by DIC corporation; "828 US", "jER 828 EL" (bisphenol A type epoxy resin), "jER 807" (bisphenol F type epoxy resin), and "jER 152" (phenol novolac type epoxy resin) manufactured by Mitsubishi chemical company; "630" and "630 LSD" manufactured by Mitsubishi chemical corporation, "ED-523T" (ADEKA Glycerol) manufactured by ADEKA corporation, "EP-3980S" (glycidyl amine epoxy resin), and "EP-4088S" (dicyclopentadiene epoxy resin); "ZX 1059" (a mixture of bisphenol a type epoxy resin and bisphenol F type epoxy resin) manufactured by NIPPON STEEL Chemical & Material co., Ltd.) (NIPPON STEEL Chemical); "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX; "CELLOXIDE 2021P" (alicyclic epoxy resin having an ester skeleton) and "PB-3600" (epoxy resin having a butadiene structure) manufactured by Dailuo corporation; "ZX 1658" and "ZX 1658 GS" (liquid 1, 4-glycidylcyclohexane) manufactured by Nippon iron chemical materials Co., Ltd. These may be used alone or in combination of two or more.

The solid epoxy resin is preferably a naphthalene type tetrafunctional epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthylene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol A type epoxy resin, a tetraphenylethane type epoxy resin, more preferably a naphthalene type tetrafunctional epoxy resin, a naphthol type epoxy resin, or a biphenyl type epoxy resin. Specific examples of the solid epoxy resin include: "HP 4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), "N-690" (cresol novolak type epoxy resin), "N-695" (cresol novolak type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "HP-7200 HH", "HP-7200H", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" and "HP 6000" (naphthylene ether type epoxy resin) manufactured by DIC corporation; "EPPN-502H" (trisphenol type epoxy resin), "NC 7000L" (naphthol novolac type epoxy resin), "NC 3000H", "NC 3000L" and "NC 3100" (biphenyl type epoxy resin) manufactured by japan chemicals; ESN475V (naphthalene type epoxy resin) and ESN485 (naphthol novolac type epoxy resin) manufactured by Nippon iron chemical Co., Ltd; "YX 4000H", "YL 6121" (biphenyl type epoxy resin), "YX 4000 HK" (biphenol type epoxy resin), "YX 8800" (anthracene type epoxy resin) manufactured by Mitsubishi chemical company; PG-100 (manufactured by Osaka gas chemical Co., Ltd.), "CG-500 (manufactured by Osaka gas chemical Co., Ltd.)," YL7760 (bisphenol AF type epoxy resin), "YL 7800 (fluorene type epoxy resin)," JeR1010 (solid bisphenol A type epoxy resin), "JeR 1031S (tetraphenylethane type epoxy resin), etc. These may be used alone or in combination of two or more.

When the liquid epoxy resin and the solid epoxy resin are used in combination as the component (B), the amount ratio thereof (liquid epoxy resin: solid epoxy resin) is preferably 1: 0.1-1: 4, more preferably 1: 0.3-1: 3.5, more preferably 1: 0.6-1: 3.

the epoxy equivalent of the epoxy resin as the component (B) is preferably 50 g/eq.about 5000 g/eq.more preferably 50 g/eq.about 3000 g/eq.further more preferably 80 g/eq.about 2000 g/eq.further more preferably 110 g/eq.about 1000 g/eq.. When the amount is within this range, the crosslinking density of the cured product becomes sufficient, and a magnetic layer having a small surface roughness can be provided. The epoxy equivalent can be measured according to JIS K7236, and is the mass of a resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of the epoxy resin as the component (B) is preferably 100 to 5000, more preferably 250 to 3000, further preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a weight average molecular weight in terms of polystyrene measured by a Gel Permeation Chromatography (GPC) method.

As the active ester resin, a resin having 1 or more active ester groups in 1 molecule can be used. Among them, as the active ester resin, a resin having 2 or more ester groups having high reactivity in 1 molecule, such as phenol esters, thiophenol esters, N-hydroxylamine esters, and esters of heterocyclic hydroxy compounds, is preferable. The active ester resin is preferably a compound obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxyl compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxyl compound is preferable, and an active ester resin obtained from a carboxylic acid compound and a phenol compound (phenol compound) and/or a naphthol compound is more preferable.

Examples of the carboxylic acid compound include: benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like.

Examples of the phenol compound or naphthol compound include: hydroquinone, resorcinol, bisphenol a, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol a, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α -naphthol, β -naphthol, 1, 5-dihydroxynaphthalene, 1, 6-dihydroxynaphthalene, 2, 6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolac (phenol novolac), and the like. Here, the "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing 2 molecules of phenol with 1 molecule of dicyclopentadiene.

Preferred specific examples of the active ester resin include: an active ester resin containing a dicyclopentadiene type diphenol structure, an active ester resin containing a naphthalene structure, an active ester resin containing an acetyl compound of a phenol novolac resin (phenol novolac), and an active ester resin containing a benzoyl compound of a phenol novolac resin. Among them, active ester resins having a naphthalene structure and active ester resins having a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" means a divalent structural unit formed from phenylene-dicyclopentylene (ジシクロペンチレン) -phenylene.

As the commercially available active ester-based resins, examples of the active ester-based resin having a dicyclopentadiene type diphenol structure include "EXB 9451", "EXB 9460S", "HPC-8000-65T", "HPC-8000H-65 TM", "EXB-8000L-65 TM" (manufactured by DIC Co., Ltd.); examples of the active ester-based resin having a naphthalene structure include "EXB 9416-70 BK" and "EXB-8150-65T" (available from DIC); examples of the active ester resin containing an acetylated novolak resin include "DC 808" (manufactured by mitsubishi chemical corporation); examples of the active ester resin containing a benzoyl compound of a novolak resin include "YLH 1026" (manufactured by Mitsubishi chemical corporation); examples of the active ester resin of the acetylated novolak resin include "DC 808" (manufactured by Mitsubishi chemical corporation); examples of the active ester resin of the benzoyl compound of the novolak resin include "YLH 1026" (manufactured by mitsubishi chemical corporation), "YLH 1030" (manufactured by mitsubishi chemical corporation), and "YLH 1048" (manufactured by mitsubishi chemical corporation).

As the phenol-based resin (phenol-based resin) and the naphthol-based resin, resins having a novolac structure (novolac structure) are preferred from the viewpoint of heat resistance and water resistance. In addition, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol (phenol) -based resin is more preferable.

Specific examples of the phenol resin (phenol resin) and naphthol resin include: "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Minghem chemical Co., Ltd, "NHN", "CBN", "GPH" manufactured by Japan chemical Co., Ltd, "SN 170", "SN 180", "SN 190", "SN 475", "SN 485", "SN 495V", "SN 375", "SN 395", "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P" and "EXB-9500" manufactured by DIC Co., Ltd.

Specific examples of the benzoxazine-based resin include: JBZ-OD100 (benzoxazine ring equivalent 218), JBZ-OP100D (benzoxazine ring equivalent 218) and ODA-BOZ (benzoxazine ring equivalent 218) manufactured by JFE chemical company; "P-d" (benzoxazine ring equivalent 217) and "F-a" (benzoxazine ring equivalent 217) manufactured by four national chemical industries, Inc.; "HFB 2006M" (benzoxazine ring equivalent 432) manufactured by Showa Polymer Co.

Examples of cyanate ester-based resins include: bifunctional cyanate ester resins such as bisphenol a dicyanate, polyphenol cyanate ester, oligo (3-methylene-1, 5-phenylene cyanate ester), 4 '-methylenebis (2, 6-dimethylphenyl cyanate ester), 4' -ethylenediphenyl dicyanate ester, hexafluorobisphenol a dicyanate ester, 2-bis (4-cyanate ester) phenylpropane, 1-bis (4-cyanate ester phenylmethane), bis (4-cyanate ester-3, 5-dimethylphenyl) methane, 1, 3-bis (4-cyanate ester-phenyl-1- (methylethylidene)) benzene, bis (4-cyanate ester phenyl) sulfide, and bis (4-cyanate ester phenyl) ether; polyfunctional cyanate ester resins derived from phenol novolac resins, cresol novolac resins, and the like; prepolymers obtained by triazinating a part of these cyanate ester resins, and the like. Specific examples of cyanate ester resins include "PT 30" and "PT 60" (both phenol novolac type polyfunctional cyanate ester resins), "ULL-950S" (polyfunctional cyanate ester resins), "BA 230" and "BA 230S 75" (prepolymers in which a part or all of bisphenol a dicyanate ester is triazinized to form a trimer), which are manufactured by Lonza Japan.

Specific examples of the carbodiimide-based resin 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 Chemicals; stabaxol (registered trademark) P (carbodiimide equivalent: 302) manufactured by Rhein Chemie.

Examples of the amine-based resin include resins having 1 or more amino groups in 1 molecule, and examples thereof include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, and the like, and among them, aromatic amines are preferable from the viewpoint of exhibiting the desired effect of the present invention. The amine-based resin is preferably a primary or secondary amine, more preferably a primary amine. Specific examples of the amine-based curing agent include: 4,4 '-methylenebis (2, 6-dimethylaniline), diphenyldiaminosulfone, 4' -diaminodiphenylmethane, 4 '-diaminodiphenylsulfone, 3' -diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4 '-diaminodiphenyl ether, 3' -dimethyl-4, 4 '-diaminobiphenyl, 2' -dimethyl-4, 4 '-diaminobiphenyl, 3' -dihydroxybenzidine, 2-bis (3-amino-4-hydroxyphenyl) propane, 3-dimethyl-5, 5-diethyl-4, 4-diphenylmethanediamine, 2-bis (4-aminophenyl) propane, diphenylmethanesulphone, 4 '-diaminodiphenylmethanesulphone, 4' -diaminodiphenylsulphone, 3 '-diaminodiphenylsulphone, m-phenylenediamine, 2-bis (4-aminophenyl) propane, diphenylmethanesulphone, 4-methyl-4, 3' -diaminodiphenylmethanesulphone, 2 '-diaminodiphenylmethanesulphone, 2' -diaminobenzenesulphone, 2,3 '-diaminobenzenesulphone, 2-bis (4-amino-4-diaminobenzenesulphone), 2-benzenesulphone, 4-diaminobenzenesulphone, 4-diaminobenzenesulphone, 2, 4-benzenesulphone, 2' -diaminobenzenesulphone, 2,4, 2,4 '-diaminobenzenesulphone, 4, 2, 4' -diaminobenzenesulphone, 2,4, 2,4, 2,4, 2, and so, 4, 2,2, 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' -bis (4-aminophenoxy) biphenyl, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (3-aminophenoxy) phenyl) sulfone and the like. As the amine-based resin, commercially available ones can be used, and examples thereof include: "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", "KAYAHARD A-S" manufactured by Nippon chemical company, "Epicure (エピキュア) W" manufactured by Mitsubishi chemical company, and the like.

Examples of the acid anhydride resin include resins having 1 or more acid anhydride groups in 1 molecule. Specific examples of the acid anhydride resin 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, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4' -diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9 b-hexahydro-5- (tetrahydro-2, 5-dioxo-3-furanyl) -naphtho [1,2-C furan-1, 3-dione, ethylene glycol bis (trimellitic anhydride ester), styrene-maleic acid resin obtained by copolymerizing styrene with maleic acid, and other polymer type acid anhydrides.

When the component (B) contains an epoxy resin and a curing agent, the amount ratio of the epoxy resin to the whole curing agent is preferably in the range of 1:0.01 to 1:5, more preferably 1:0.5 to 1:3, and still more preferably 1:1 to 1:2, in terms of the ratio of [ total number of epoxy groups of epoxy resin ]/[ total number of reactive groups of curing agent ]. Here, the "number of epoxy groups of the epoxy resin" refers to a total value of all values obtained by dividing the mass of nonvolatile components of the epoxy resin present in the magnetic composition by the epoxy equivalent weight. The "number of active groups (reactive groups) of the curing agent" is a total value of all the values obtained by dividing the mass of nonvolatile components of the curing agent present in the magnetic composition by the equivalent weight of the active groups.

Thermoplastic resins

The weight average molecular weight of the thermoplastic resin in terms of polystyrene is preferably 3 ten thousand or more, more preferably 5 ten thousand or more, and still more preferably 10 ten thousand or more. Further, it is preferably 100 ten thousand or less, more preferably 75 ten thousand or less, further preferably 50 ten thousand or less. The polystyrene-equivalent weight average molecular weight of the thermoplastic resin was measured by a Gel Permeation Chromatography (GPC) method. Specifically, the weight average molecular weight of the thermoplastic resin in terms of polystyrene can be measured using "LC-9A/RID-6A" manufactured by Shimadzu corporation as a measuring apparatus, using "Shodex K-800P/K-804L/K-804L" manufactured by Showa Denko K.K., as a column, using chloroform or the like as a mobile phase, at a column temperature of 40 ℃ and calculated using a calibration curve of standard polystyrene.

Examples of the phenoxy resin include phenoxy resins having at least one skeleton selected from a bisphenol a skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a phenol (novolac) skeleton, a biphenyl skeleton, a fluorene skeleton, a dicyclopentadiene skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The phenoxy resin may have any functional group such as a phenolic hydroxyl group or an epoxy group at its terminal. The phenoxy resin may be used singly or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both phenoxy resins having a bisphenol a skeleton), and "YX 8100" (phenoxy resin having a bisphenol S skeleton), and "YX 6954" (phenoxy resin having a bisphenol acetophenone skeleton), which are manufactured by mitsubishi chemical corporation, and further include "FX 280" and "FX 293", which are manufactured by mitsubishi chemical corporation, "YL 7500BH 30", "YX 6954BH 30", "YX 7553BH 30", "YL 7769BH 30", "YL 6794", "YL 7213", "YL 7290", and "YL 7482", which are manufactured by mitsubishi chemical corporation.

The acrylic resin is preferably a functional group-containing acrylic resin, more preferably an epoxy group-containing acrylic resin having a glass transition temperature of 25 ℃ or lower, from the viewpoint of further lowering the thermal expansion coefficient and the elastic modulus.

The number average molecular weight (Mn) of the functional group-containing acrylic resin is preferably 10000 to 1000000, more preferably 30000 to 900000.

The functional group equivalent of the acrylic resin having functional groups is preferably 1000 to 50000, more preferably 2500 to 30000.

As the epoxy group-containing acrylic resin having a glass transition temperature of 25 ℃ or lower, an epoxy group-containing acrylate copolymer resin having a glass transition temperature of 25 ℃ or lower is preferred, and specific examples thereof include "SG-80H" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn:350000g/mol, epoxy value: 0.07eq/kg, glass transition temperature: 11 ℃) manufactured by Nagase ChemteX) and "SG-P3" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn:850000g/mol, epoxy value: 0.21eq/kg, glass transition temperature: 12 ℃) manufactured by Nagase ChemteX).

Specific examples of the polyvinyl acetal resin and the Butyral resin include electrochemical Butyral (Denka butyl) "4000-2", "5000-A", "6000-C" and "6000-EP" manufactured by the electrochemical chemical industry Co., Ltd, S-LEC BH series, BX series, "KS-1" and other KS series, "BL-1" and other BL series, BM series and the like manufactured by the Water chemical industry Co., Ltd.

Specific examples of the polyimide resin include "RIKACOAT SN 20" and "RIKACOAT PN 20" manufactured by shin-shin chemical company. Specific examples of the polyimide resin include modified polyimides such as linear polyimides obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (polyimides described in Japanese patent application laid-open Nos. 2006 and 37083), and polyimides having a polysiloxane skeleton (polyimides described in Japanese patent application laid-open Nos. 2002 and 12667 and 2000 and 319386).

Specific examples of the polyamide-imide resin include "VYLOMAX HR11 NN" and "VYLOMAX HR16 NN" manufactured by tokyo corporation. Specific examples of the polyamideimide resin include modified polyamideimides such as "KS 9100" and "KS 9300" (polyamideimide having a polysiloxane skeleton) manufactured by hitachi chemical industry co.

Specific examples of the polyether sulfone resin include "PES 5003P" manufactured by sumitomo chemical corporation. Specific examples of the polyphenylene ether resin include an oligophenylene ether-styrene resin having a vinyl group "OPE-2 St 1200" manufactured by Mitsubishi gas chemical corporation.

Specific examples of the polysulfone resin include polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

Among them, as the thermoplastic resin, one or more thermoplastic resins selected from phenoxy resins, polyvinyl acetal resins, butyral resins, and acrylic resins having a weight average molecular weight of 3 to 100 ten thousand are preferable.

From the viewpoint of obtaining a magnetic layer exhibiting good mechanical strength and insulation reliability, the content of the (B) binder resin is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and still more preferably 1 mass% or more, with 100 mass% of nonvolatile components in the magnetic composition. The upper limit is not particularly limited as long as the effects of the present invention are exhibited, and is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less.

Further, (B) the binder resin preferably contains an epoxy resin, more preferably a liquid epoxy resin. The liquid epoxy resin is preferably at least 1 mass%, more preferably at least 1.5 mass%, and still more preferably at least 2 mass% with respect to 100 mass% of the component (A). The upper limit is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less.

(C) curing accelerator

The magnetic composition may further comprise (C) a curing accelerator as an optional component.

Examples of the curing accelerator include amine curing accelerators, imidazole curing accelerators, phosphorus curing accelerators, guanidine curing accelerators, and metal curing accelerators. The curing accelerator is preferably an amine curing accelerator or an imidazole curing accelerator, and more preferably an imidazole curing accelerator, from the viewpoint of reducing the viscosity of the magnetic composition. The curing accelerator may be used alone or in combination of two or more.

Examples of the amine-based curing accelerator include: trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4, 6-tris (dimethylaminomethyl) phenol, 1, 8-diazabicyclo [5.4.0] undecene, etc., preferably 4-dimethylaminopyridine and 1, 8-diazabicyclo [5.4.0] undecene.

As the amine-based curing accelerator, commercially available products can be used, and examples thereof include "PN-50", "PN-23" and "MY-25" manufactured by Ajinomoto Fine-Techni, Inc.

Examples of the imidazole-based curing accelerator include: 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-methylimidazole, 1-methylimidazole, 2-propylidenedicarboxylic acid, 2-methylimidazole, 2-arylimidazole, 2-methylimidazole, and mixtures thereof, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-diamino-6- [2' -methylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -undecylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -ethyl-4 ' -methylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -methylimidazolyl- (1') ] -ethyl-s-triazine isocyanuric acid adduct, and mixtures thereof, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4, 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2, 3-dihydro-1H-pyrrolo [1,2-a ] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, imidazole compounds such as 2-methylimidazoline and 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole.

As the imidazole-based curing accelerator, commercially available products can be used, and examples thereof include "2P 4 MZ" and "2 PHZ-PW" manufactured by Sizhou chemical industries, and "P200-H50" manufactured by Mitsubishi chemical industries.

Examples of the phosphorus-based curing accelerator 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.

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

Examples of the metal-based curing accelerator include: an organometallic complex or an organometallic salt of a metal such as cobalt, copper, zinc, iron, nickel, manganese, tin, or the like. Specific examples of the organometallic complex include: organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, organic zinc complexes such as zinc (II) acetylacetonate, organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

The curing accelerator (C) is preferably at least one selected from the group consisting of an acid anhydride-based epoxy resin curing agent, an amine-based curing accelerator and an imidazole-based curing accelerator, and more preferably at least one selected from the group consisting of an amine-based curing accelerator and an imidazole-based curing accelerator, from the viewpoint of obtaining the desired effects of the present invention.

From the viewpoint of accelerating the curing of the magnetic composition, the content of the (C) curing accelerator is preferably 0.01 mass% or more, more preferably 0.03 mass% or more, further more preferably 0.05 mass% or more, and the upper limit is preferably 0.5 mass% or less, more preferably 0.3 mass% or less, further more preferably 0.1 mass% or less, with respect to 100 mass% of nonvolatile components in the magnetic composition.

(D) dispersant

The magnetic composition may further comprise (D) a dispersant as an optional component.

Examples of the dispersant (D) include: phosphate dispersants such as polyoxyethylene alkyl ether phosphate esters; anionic dispersants such as sodium dodecylbenzenesulfonate, sodium laurate and ammonium salts of polyoxyethylene alkyl ether sulfate; and nonionic dispersants such as organosiloxane dispersants, acetylene glycol (acetylene glycol), polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, and polyoxyethylene alkylamides. Among them, anionic dispersants are preferred. One kind of the dispersant may be used alone, or two or more kinds may be used in combination.

Commercially available phosphoric ester-based dispersants can be used. Examples of commercially available products include "RS-410", "RS-610" and "RS-710" of the "Phosphanol (フォスファノール)" series manufactured by Toho chemical industries, Ltd.

Examples of commercially available organosiloxane-based dispersants include: BYK347 and BYK348 manufactured by BYK-Chemie, Inc.

As the polyoxyalkylene-based dispersant, commercially available products include: "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F", and "SC-0708A", and "HKM-50A", which are manufactured by "MALIALIIM" series, manufactured by Nissan oil Co., Ltd.

Examples of commercially available acetylene glycol include: "Surfynol" series "82", "104", "440", "465" and "485", and "Olefin Y (オレフィン Y)" manufactured by Air Products and Chemicals Inc.

From the viewpoint of remarkably exerting the effect of the present invention, the content of the (D) dispersant is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, further more preferably 0.5 mass% or more, and the upper limit is preferably 5 mass% or less, more preferably 3 mass% or less, further more preferably 1 mass% or less, when the nonvolatile content in the magnetic composition is set to 100 mass%.

< (E) other additives

The magnetic composition may further contain (E) other additives as needed, and examples of such other additives include: a curing retarder such as triethyl borate for improving the pot life (pot life), an inorganic filler (except for a material belonging to the magnetic powder), a flame retardant, an organic filler, an organic copper compound, an organic zinc compound, an organic cobalt compound, and other organic metal compounds, and a resin additive such as a thickener, a defoaming agent, a leveling agent, an adhesion imparting agent, and a coloring agent.

The magnetic composition may be a paste-like composition which generally exhibits such a characteristic that the viscosity is low even if the composition does not contain a solvent. Therefore, the content of the solvent contained in the magnetic composition is preferably less than 1.0% by mass, more preferably 0.8% by mass or less, further preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, based on the total mass of the magnetic composition. The lower limit is not particularly limited, and may be 0.001% by mass or more or contain no solvent. The magnetic composition can be reduced in viscosity by using a thermosetting resin or the like in a liquid state in general even if a solvent is not contained. By making the amount of the solvent in the magnetic composition small, generation of voids (void) due to volatilization of the solvent can be suppressed, and the handling property and the workability can be made excellent.

< method for producing magnetic composition >

The magnetic composition can be produced by, for example, a method of stirring the components to be blended with a stirring device such as a three-roll mill or a rotary mixer.

< physical Properties of magnetic composition, etc. >

Since the magnetic composition contains the component (a) having a predetermined particle size distribution, a cured product of the magnetic composition has a characteristic of high relative permeability. Therefore, the cured product of the magnetic composition brings about a magnetic layer having a high relative permeability. The cured product has a relative permeability at a frequency of 10MHz of preferably 15 or more, more preferably 17 or more, and further more preferably 19 or more. The upper limit is not particularly limited, and may be 100 or less. The relative permeability can be measured by the method described in the examples described later.

Since the magnetic composition contains the component (a) having a predetermined particle size distribution, a cured product of the magnetic composition has a low magnetic loss. Therefore, the cured product of the magnetic composition brings about a magnetic layer having low magnetic loss. The magnetic loss at a frequency of 10MHz of the cured product is preferably less than 0.08, more preferably 0.05 or less, further preferably 0.04 or less and less than 0.05. The lower limit is not particularly limited, and may be 0.0001 or more. The magnetic loss can be measured by the method described in the examples described later.

Magnetic compositions generally exhibit such a characteristic of low viscosity. Therefore, the magnetic composition has a characteristic of being a paste (a pasty magnetic composition), and can be preferably used as a magnetic composition for filling a through hole. Further, the magnetic composition can be preferably used as a magnetic composition for forming an inductor element used for manufacturing the inductor element.

[ magnetic sheet ]

The magnetic sheet comprises a support and a magnetic composition layer formed of the magnetic composition of the present invention provided on the support.

From the viewpoint of thinning, the thickness of the magnetic composition layer is preferably 250 μm or less, more preferably 200 μm or less. The lower limit of the thickness of the magnetic composition layer is not particularly limited, and may be usually 5 μm or more and 10 μm or more.

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, examples of the plastic material include: polyethylene terephthalate (hereinafter sometimes referred to simply as "PET"), polyester such as polyethylene naphthalate (hereinafter sometimes referred to simply as "PEN"), acrylic polymer such as polycarbonate (hereinafter sometimes referred to simply as "PC") and polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and particularly, inexpensive polyethylene terephthalate is preferable.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, and copper foil is preferred. As the copper foil, a foil formed of a single metal of copper may be used, and a foil formed of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, or the like) may also be used.

The surface of the support to be bonded to the magnetic composition layer may be subjected to a matting treatment or a corona treatment.

Further, as the support, a support with a release layer having a release layer on a surface bonded to the magnetic composition layer can be used. Examples of the release agent used for the release layer of the support having the release layer include at least one selected from alkyd resins, polyolefin resins, polyurethane resins, and silicone resins. As the support having a release layer, commercially available products can be used, and examples thereof include: "PET 501010", "SK-1", "AL-5", "AL-7", manufactured by Lindelco, as a PET film having a release layer containing an alkyd resin-based release agent as a main component; "Lumiror T60" manufactured by Dongli corporation; "Purex" manufactured by Imperial corporation; unipel manufactured by UNITIKA, Inc.

The thickness of the support is not particularly limited, but is preferably in the range of 5 to 75 μm, more preferably 10 to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably within the above range.

In the magnetic sheet, a protective film selected for the support may be laminated on the surface of the magnetic composition layer that is not bonded to the support (i.e., the surface on the side opposite to the support). The thickness of the protective film is not particularly limited, and is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust or the like to the surface of the magnetic composition layer and formation of scratches can be suppressed. The magnetic sheet can be rolled for storage. When the magnetic sheet has a protective film, the protective film can be peeled off and used.

The magnetic sheet can be manufactured, for example, by: the magnetic composition is applied to the support using a die coater or the like to form a magnetic composition layer. If necessary, a resin varnish dissolved in an organic solvent may be prepared, and the resin varnish may be applied to a support. When an organic solvent is used, the coating may be followed by drying, if necessary.

The drying may be carried out by heating, hot air blowing, or the like. The drying conditions are not particularly limited, and drying is performed so that the content of the organic solvent in the magnetic composition layer becomes 10 mass% or less, preferably 5 mass% or less. The magnetic composition layer can be formed by drying at 50 to 150 ℃ for 3 to 10 minutes, although the composition may vary depending on the components contained in the magnetic composition.

The magnetic sheet can be rolled for storage. When the magnetic sheet has a protective film, the protective film can be peeled off and used.

[ Circuit Board and method for manufacturing the same ]

The circuit board of the present invention includes a magnetic layer as a cured product of the magnetic composition. The circuit board of the first embodiment includes: a substrate having a through-hole, and a cured product of the magnetic composition of the present invention filled in the through-hole. In addition, the circuit board of the second embodiment includes: a magnetic layer formed from a cured product of the magnetic composition layer of the magnetic sheet. Hereinafter, a first embodiment and a second embodiment of a method for manufacturing a circuit board will be described. However, the method of manufacturing the circuit board according to the present invention is not limited to the first and second embodiments described below.

< first embodiment >

The circuit board according to the first embodiment can be manufactured by a manufacturing method including, for example, the following steps (1) to (5). In the first embodiment, the magnetic layer is preferably formed using a magnetic composition, and more preferably, a paste-like magnetic composition. The manufacturing method comprises the following steps:

(1) filling a magnetic composition into a through hole of a substrate having the through hole;

(2) a step of obtaining a cured product by thermally curing the magnetic composition;

(3) polishing the surface of the cured product or the magnetic composition;

(4) a step of roughening the cured product; and

(5) forming a conductor layer on the roughened surface of the cured product;

the method for manufacturing a circuit board of the present invention may be performed in the order of steps (1) to (5), or step (2) may be performed after step (3).

< Process (1) >

The step (1) may include a step of preparing a magnetic composition. The magnetic composition is as described above.

In addition, when the step (1) is performed, as shown in an example in fig. 1, a step of preparing a core substrate 10 may be included, the core substrate 10 including: a support substrate 11, and a first metal layer 12 and a second metal layer 13 formed of a metal such as copper foil and provided on both surfaces of the support substrate 11. Examples of the material of the support substrate 11 include: an insulating base material such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, or a thermosetting polyphenylene ether substrate. Examples of the material of the first metal layer and the second metal layer include a copper foil with a carrier and a material of a conductor layer described later.

Further, as shown in fig. 2, the method may include a step of forming the through hole 14 in the core substrate 10. The through-hole 14 may be formed by, for example, drilling, laser irradiation, plasma irradiation, or the like. Specifically, the through hole 14 can be formed by forming a through hole in the core substrate 10 using a drill or the like.

The formation of the through-hole 14 may be carried out using a commercially available drill bit device. Examples of a drill device commercially available include "ND-1S 211" manufactured by Hitachi-Viya mechanical Co.

After the core substrate 10 is formed with the through-hole 14, as an example shown in fig. 3, the following may be included: and a step of performing roughening treatment of the core substrate 10 to form plating layers 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.

As the above-mentioned roughening treatment, any of dry and wet roughening treatments can be performed. Examples of the dry roughening treatment include plasma treatment. In addition, as an example of the wet-type roughening treatment, there is a method of sequentially performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralizing treatment with a neutralizing liquid.

The plating layer 20 can be formed by a plating method, and the step of forming the plating layer 20 by the plating method is the same as the formation of the conductor layer in step (5) described later.

After the core substrate 10 is prepared, the through hole 14 is filled with the magnetic composition 30a as shown in an example in fig. 4. The filling can be performed, for example, by a printing method. Examples of the printing method include: a method of printing the magnetic composition 30a to the through-hole 14 via a squeegee (squeegee), a method of printing the magnetic composition 30a via a cartridge (cartridge), a method of performing mask printing to print the magnetic composition 30a, a roll coating method, an inkjet method, and the like.

< Process (2) >

In the step (2), after the magnetic composition 30a is filled into the through-hole 14, the magnetic composition 30a is thermally cured, and a cured layer (magnetic layer) 30 is formed in the through-hole 14 as shown in fig. 5. The heat curing conditions of the magnetic composition 30a vary depending on the composition or kind of the magnetic composition 30a, and the curing temperature is preferably 120 ℃ or higher, more preferably 130 ℃ or higher, still more preferably 150 ℃ or higher, preferably 245 ℃ or lower, more preferably 220 ℃ or lower, and still more preferably 200 ℃ or lower. The curing time of the magnetic composition 30a is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 120 minutes or less, more preferably 100 minutes or less, further more preferably 90 minutes or less.

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

The magnetic composition 30a may be subjected to a preliminary heat treatment of heating at a temperature lower than the curing temperature before the magnetic composition 30a is thermally cured. For example, the magnetic composition 30a may be preheated for usually 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes) at a temperature of usually 50 ℃ or more and less than 120 ℃ (preferably 60 ℃ or more and 110 ℃ or less, more preferably 70 ℃ or more and 100 ℃ or less) before the magnetic composition 30a is thermally cured.

In the case where the step (3) is performed after the step (2), heat treatment may be performed as necessary for the purpose of further improving the degree of curing of the magnetic layer or the like after the step (2) and before the step (3). The temperature in the heat treatment may be the curing temperature described above, and is preferably 120 ℃ or higher, more preferably 130 ℃ or higher, further preferably 150 ℃ or higher, preferably 245 ℃ or lower, more preferably 220 ℃ or lower, and further more preferably 200 ℃ or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 90 minutes or less, further preferably 70 minutes or less, further preferably 60 minutes or less.

In the case where the step (3) is performed before the step (2), a preheating treatment in which heating is performed at a temperature lower than the curing temperature of the magnetic composition may be performed before the step (3). The temperature in the preliminary heating treatment is preferably 100 ℃ or higher, more preferably 110 ℃ or higher, further preferably 120 ℃ or higher, preferably 245 ℃ or lower, more preferably 220 ℃ or lower, further preferably 200 ℃ or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 90 minutes or less, further preferably 70 minutes or less, further preferably 60 minutes or less.

< Process (3) >

In step (3), as in the example shown in fig. 6, the excess magnetic layer 30 protruding from or adhering to the core substrate 10 is removed by polishing, and planarization is performed. As a polishing method, a method capable of polishing an excess magnetic layer 30 protruding from or attached to the core substrate 10 may be used. Examples of such a polishing method include buffing and belt polishing. Examples of commercially available polishing and polishing apparatuses include "NT-700 IM" manufactured by Shijing notation.

The arithmetic average roughness (Ra) of the polished surface of the magnetic layer (after thermal curing of the magnetic layer) is preferably 300nm or more, more preferably 350nm or more, and still more preferably 400nm or more, from the viewpoint of improving the adhesion to the plating layer. The upper limit is preferably 1000nm or less, more preferably 900nm or less, further preferably 800nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

< Process (4) >

In the step (4), the surface polished in the step (3) is subjected to roughening treatment (desmearing treatment). The steps and conditions of the roughening step are not particularly limited, and known steps and conditions generally used in a method for producing a multilayer printed wiring board can be used. As the roughening step, for example, the roughening treatment can be performed on the first magnetic layer 32 by sequentially performing a swelling treatment with a swelling solution, a roughening treatment with an oxidizing agent, and a neutralizing treatment with a neutralizing solution.

The swelling solution that can be used in the roughening step is not particularly limited, and examples thereof include an alkali solution and a surfactant solution, and an alkali solution is preferred. The alkali solution as the swelling solution is preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of commercially available Swelling liquids include "spinning Dip securigant P" and "spinning Dip securigant SBU" manufactured by amatt JAPAN (ato ech JAPAN).

The swelling treatment using the swelling solution is not particularly limited, and may be performed, for example, by immersing the core base material 20 provided with the first magnetic layer 32 in the swelling solution at 30 to 90 ℃ for 1 to 20 minutes. From the viewpoint of controlling the swelling of the resin constituting the first magnetic layer 32 to an appropriate level, it is preferable to immerse the first magnetic layer 32 in a swelling solution at 40 to 80 ℃ for 5 to 15 minutes.

The oxidizing agent that can be used for the roughening treatment with the oxidizing agent is not particularly limited, and examples thereof include an alkaline permanganic acid solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganic acid solution is preferably performed by immersing first magnetic layer 32 in a solution of an oxidizing agent heated to 60 to 80 ℃ for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5 to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganic acid solutions such as "Concentrate Compact P" and "Dosing solution securigant P" manufactured by anmant japan.

The neutralizing solution usable in the neutralization treatment is preferably an acidic aqueous solution, and examples of commercially available products include "Reduction solution securiganteh P" manufactured by amatt japan. The neutralization treatment with the neutralization solution can be performed by immersing the treated surface subjected to the roughening treatment with the oxidant solution in the neutralization solution at 30 to 80 ℃ for 5 to 30 minutes. From the viewpoint of workability, the first magnetic layer 32 subjected to the roughening treatment with the oxidizing agent solution is preferably immersed in a neutralizing solution at 40 to 70 ℃ for 5 to 20 minutes.

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

< Process (5) >

In step (5), as shown in fig. 7, a conductor layer 40 is formed on the polished surface of the magnetic layer 30 and the core substrate. Further, after the conductor layer 40 is formed, as shown in an example in fig. 8, the conductor layer 40, the first metal layer 12, the second metal layer 13, and a part of the plating layer 20 may be removed by etching or the like to form a patterned conductor layer 41. In fig. 7, the conductor layers 40 are formed on both surfaces of the core substrate 10, but the conductor layers 40 may be formed only on one surface of the core substrate 10.

Examples of the method for forming the conductor layer include plating, sputtering, and vapor deposition, and among them, plating is preferred. In a preferred embodiment, plating is performed on the surface of the cured product by an appropriate method such as a semi-additive method or a full-additive method to form a patterned conductor layer having a desired wiring pattern. Examples of the material of the conductor layer include: a single metal such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, indium, or the like; an alloy of two or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Among them, from the viewpoint of versatility, cost, ease of patterning, and the like, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferably used, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or a nickel-chromium alloy is more preferably used, and copper is still more preferably used.

Here, an example of an embodiment in which a patterned conductor layer is formed on a polished surface of a cured product will be described in detail. A plating seed layer is formed on the polished surface of the cured product by electroless plating. Next, an electrolytic plating layer is formed on the formed plating seed layer by electrolytic plating, and the unnecessary plating seed layer is removed by etching or the like as necessary, whereby a conductor layer having a desired wiring pattern can be formed. After the formation of the conductor layer, annealing treatment may be performed as necessary for the purpose of improving the peel strength of the conductor layer and the like. The annealing treatment can be performed by heating the circuit board at 150 to 200 ℃ for 20 to 90 minutes, for example.

From the viewpoint of thinning, the thickness of the patterned conductor layer is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, yet more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

< second embodiment >

The circuit board according to the second embodiment includes a magnetic layer formed using a cured product of the magnetic composition. In the second embodiment, it is preferable to form the magnetic layer using a magnetic sheet. A second embodiment of the method for manufacturing a product substrate will be described below. Descriptions of parts overlapping with those of the first embodiment are omitted as appropriate.

The circuit board according to the second embodiment can be manufactured by a manufacturing method including, for example, the following steps (a) to (D). The manufacturing method comprises the following steps:

(A) a step of forming a magnetic layer by laminating a magnetic sheet on the inner layer substrate so that the magnetic composition layer is bonded to the inner layer substrate,

(B) a step of forming a hole in the magnetic layer,

(C) a step of roughening the surface of the magnetic layer, and

(D) and forming a conductor layer on the polished surface of the magnetic layer.

The above-described steps (a) to (D) in the production of the circuit board will be described in detail below.

< Process (A) >

The step (A) is: and a step of forming a magnetic layer by laminating a magnetic sheet on the inner layer substrate so that the magnetic composition layer is bonded to the inner layer substrate. As one embodiment of the step (a), a magnetic sheet is laminated on the inner layer substrate so that the magnetic composition layer is bonded to the inner layer substrate, and the magnetic composition layer is thermally cured to form a magnetic layer.

In the step (a), as shown in an example in fig. 9, a magnetic sheet 310 including a support 330 and a magnetic composition layer 320a provided on the support 330 is laminated on the inner layer substrate 200 so that the magnetic composition layer 320a is bonded to the inner layer substrate 200.

The inner layer substrate 200 is an insulating substrate. Examples of the material of the inner layer substrate 200 include insulating base materials such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The inner layer substrate 200 may be an inner layer circuit substrate having a wiring or the like embedded in the thickness thereof.

As an example shown in fig. 9, the inner layer substrate 200 includes: first conductor layer 420 provided on first main surface 200a, and external terminal 240 provided on second main surface 200 b. The first conductor layer 420 may include a plurality of wirings. In the illustrated example, only the wiring of the coil-shaped conductive structure 400 constituting the inductor element is shown. The external terminal 240 is a terminal for electrical connection to an external device or the like, not shown. The external terminal 240 may be configured as a part of a conductor layer provided on the second main surface 200 b.

The conductive material that can constitute the first conductive layer 420 and the external terminal 240 is the same as the conductive layer described in the column "< step (5) >" of the first embodiment.

The first conductor layer 420 and the external terminal 240 may have a single-layer structure, or may have a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are stacked. The thicknesses of the first conductor layer 420 and the external terminal 240 are the same as those of the second conductor layer 440 described later.

The ratio of the line width (L)/the line pitch (S) of the first conductor layer 420 and the external terminal 240 is not particularly limited, but is usually 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 still further preferably 200/200 μm or less, from the viewpoint of reducing surface irregularities and obtaining a magnetic layer having excellent smoothness. The lower limit of the line width/pitch ratio is not particularly limited, but is preferably 1/1 μm or more from the viewpoint of making good the filling of the magnetic composition layer into the space (space) between the wirings.

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

The magnetic composition layer 320a and the inner layer substrate 200 can be bonded by, for example, heat-crimping the magnetic sheet 310 to the inner layer substrate 200 from the support 330 side. Examples of the member for heat-pressure bonding the magnetic sheet 310 to the inner layer substrate 200 (hereinafter also referred to as "heat-pressure bonding member") include a heated metal plate (stainless steel (SUS) end plate, etc.) and a metal roll (SUS roll). It is preferable that the thermocompression bonding member is not pressed by directly contacting the magnetic sheet 310, but is pressed through a sheet made of an elastic material such as heat-resistant rubber so that the magnetic sheet 310 sufficiently follows the surface irregularities of the inner layer substrate 200.

The temperature at the time of the thermal compression bonding is preferably in the range of 80 to 160 ℃, more preferably 90 to 140 ℃, further more preferably 100 to 120 ℃, the pressure at the time of the thermal compression bonding is preferably in the range of 0.098 to 1.77MPa, more preferably 0.29 to 1.47MPa, and the time at the time of the thermal compression bonding is preferably in the range of 20 to 400 seconds, more preferably 30 to 300 seconds. The magnetic sheet and the inner layer substrate are preferably bonded to each other under a reduced pressure of not more than 26.7 hPa.

The magnetic composition layer 320a of the magnetic sheet 310 and the inner substrate 200 can be bonded to each other by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Nikko & company, and a vacuum applicator (vacuum applicator) manufactured by Nikko-Materials.

After the magnetic sheet 310 and the inner layer substrate 200 are joined, the heat and pressure bonding member is pressed under normal pressure (atmospheric pressure), for example, from the support side, whereby the smoothing process of the laminated magnetic sheet 310 can be performed. The pressing conditions for the smoothing treatment may be set to the same conditions as the above-described conditions for the heat and pressure bonding of the laminate. The smoothing treatment can be performed using a commercially available laminator. The lamination and smoothing treatment can be continuously performed using a commercially available vacuum laminator as described above.

After the magnetic sheet is laminated on the inner layer substrate, the magnetic composition layer is thermally cured to form a magnetic layer. As shown in fig. 10, the magnetic composition layer 320a bonded to the inner layer substrate 200 is thermally cured to form the first magnetic layer 320.

The heat curing conditions of the magnetic composition layer 320a vary depending on the composition or kind of the magnetic composition, and the curing temperature is preferably 120 ℃ or higher, more preferably 130 ℃ or higher, still more preferably 150 ℃ or higher, preferably 245 ℃ or lower, more preferably 220 ℃ or lower, and still more preferably 200 ℃ or lower. The curing time of the magnetic composition layer 320a is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 120 minutes or less, more preferably 100 minutes or less, further more preferably 90 minutes or less.

The support 330 may be removed between the step (a) and the step (B) after the thermosetting, or may be peeled off after the step (B).

The arithmetic average roughness (Ra) before the roughening treatment of the magnetic layer is preferably 300nm or more, more preferably 350nm or more, and still more preferably 400nm or more, from the viewpoint of improving the adhesion to the plating layer. The upper limit is preferably 1000nm or less, more preferably 900nm or less, further preferably 800nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

In the step (a), instead of the magnetic sheet, the magnetic layer may be formed by applying the magnetic composition onto the inner layer substrate with a die coater or the like and thermally curing the applied composition.

< Process (B) >

In the step (B), as shown in fig. 11, a hole is formed in the first magnetic layer 320 to form a through hole (via hole) 360. The through-holes 360 serve as paths for electrically connecting the first conductor layer 420 and a second conductor layer 440, which will be described later. The formation of the through hole 360 can be performed using, for example, a drill, a laser, plasma, or the like, depending on the composition of the magnetic composition used for the formation of the magnetic layer, or the like. The size and shape of the hole may be determined as appropriate according to the design of the printed wiring board.

< Process (C) >

In the step (C), the surface of the magnetic layer having the through-holes formed thereon is roughened. The roughening treatment in the step (C) is as described in the column "< step (4) >" in the first embodiment.

In the step (C), polishing may be performed instead of roughening treatment to remove an excess magnetic layer protruding from or adhering to the core substrate 10, and planarization may be performed. The polishing method is as described above.

< Process (D) >

In step (D), as shown in an example in fig. 12, a second conductor layer 440 is formed on the first magnetic layer 320.

The conductive material that can constitute the second conductive layer 440 is the same as that of the conductive layer described in the column "< step (5) >" of the first embodiment.

From the viewpoint of reduction in thickness, the thickness of the second conductor layer 440 is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, yet more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

The second conductor layer 440 may be formed by plating. The second conductor layer 440 is preferably formed by a wet plating method such as a semi-additive method including an electroless plating step, a mask pattern forming step, an electrolytic plating step, and a rapid etching (flash) step, or a full-additive method. The second conductor layer 440 is formed by a wet plating method, so that it can be formed into the second conductor layer 440 including a desired wiring pattern. In this step, the through-hole inner wiring 360a can be formed in the through-hole 360 at a time.

The first conductor layer 420 and the second conductor layer 440 may be provided in a spiral shape, for example, as shown in fig. 13 to 15 described later. In one example, the center-side end of the spiral-shaped wiring portion of the second conductor layer 440 is electrically connected to the center-side end of the spiral-shaped wiring portion of the first conductor layer 420 via the through-hole inner wiring 360 a. The other end on the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the land (land)420a of the first conductor layer 420 via the through-hole inner wiring 360 a. Therefore, the other end of the second conductor layer 440 on the outer peripheral side of the spiral wiring portion is electrically connected to the external terminal 240 via the through-hole inner wiring 360a, the land 420a, and the through-hole inner wiring 220 a.

The coiled conductive structure 400 includes a spiral wiring portion that is a part of the first conductor layer 420, a spiral wiring portion that is a part of the second conductor layer 440, and through-hole wirings 360a that electrically connect the spiral wiring portion of the first conductor layer 420 and the spiral wiring portion of the second conductor layer 440.

After the step (D), a step of forming a magnetic layer on the conductor layer may be further performed. In detail, as shown in an example in fig. 14, the second magnetic layer 340 is formed on the first magnetic layer 320 on which the second conductor layer 440 and the through-hole interconnection 360a are formed. The second magnetic layer can be formed by the same process as that described above.

[ inductor substrate ]

The inductor substrate comprises the circuit substrate of the invention. When such an inductor substrate includes the circuit substrate obtained by the method for manufacturing a circuit substrate according to the first embodiment, the inductor pattern formed of a conductor is provided at least in part around the cured product of the magnetic composition. Such a sensor substrate can be applied to, for example, a substrate described in japanese patent laid-open publication No. 2016-.

In addition, when the circuit board obtained by the method for manufacturing a circuit board according to the second embodiment is included, the inductor substrate includes a magnetic layer and a conductive structure at least partially embedded in the magnetic layer, and includes an inductor element including the conductive structure and a part of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. Here, fig. 13 is a schematic plan view of the inductor substrate incorporating the inductor element as viewed from one side in the thickness direction thereof. Fig. 14 is a schematic view showing a cut end face of the inductor substrate cut at a position shown by a dashed line II-II shown in fig. 13. Fig. 15 is a schematic plan view for explaining the configuration of the first conductor layer in the inductor substrate.

As shown in fig. 13 and 14 as an example, the circuit board 100 is a stacked wiring board having a plurality of magnetic layers (first magnetic layer 320, second magnetic layer 340) and a plurality of conductor layers (first conductor layer 420, second conductor layer 440), that is, a stacked (built-up) magnetic layer and a stacked conductor layer. The circuit board 100 includes an inner layer board 200.

As shown in fig. 14, the first magnetic layer 320 and the second magnetic layer 340 constitute a magnetic portion 300 which is a magnetic layer that can be regarded as a single body. Therefore, the coil-shaped conductive structure 400 is provided so that at least a part thereof is embedded in the magnetic portion 300. That is, in the circuit board 100 of the present embodiment, the inductor element is constituted by the coil-shaped conductive structure 400 and the core portion that is a part of the magnetic portion 300 extending in the thickness direction of the magnetic portion 300 and surrounded by the coil-shaped conductive structure 400.

As shown as an example in fig. 15, the first conductor layer 420 includes: a spiral wiring portion for constituting the coil-shaped conductive structure 400, and a rectangular land 420a electrically connected to the via inner wiring 220 a. In the illustrated example, the spiral wiring portion includes: a linear portion, a bent portion bent at a right angle, and a detour portion detouring at the pad 420 a. In the illustrated example, the spiral wiring portion of the first conductor layer 420 has a shape that is substantially rectangular in overall outline and is wound in a counterclockwise direction from the center side toward the outer side thereof.

Similarly, a second conductor layer 440 is disposed on the first magnetic layer 320. The second conductor layer 440 includes a spiral wiring portion for constituting the coil-shaped conductive structure 400. In fig. 13 or 14, the spiral wiring portion includes a linear portion and a bent portion bent at a right angle. In fig. 13 or 14, the spiral wiring portion of the second conductor layer 440 has a shape that is substantially rectangular in overall outline and is wound clockwise from the center side to the outer side thereof.

Such an inductor substrate can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using the wiring board as an inner layer substrate. The chip inductor component may be a chip inductor component obtained by singulating the wiring board, or may be a printed wiring board having the chip inductor component mounted on the surface thereof.

Further, various forms of semiconductor devices can be manufactured using the wiring board. The semiconductor device including the wiring board can be suitably used for electric products (e.g., computers, mobile phones, digital cameras, televisions, and the like), vehicles (e.g., motorcycles, automobiles, electric trains, ships, aircrafts, and the like), and the like.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following description, "part" and "%" representing amounts refer to "part by mass" and "% by mass", respectively, unless otherwise explicitly indicated.

< example 1: preparation of magnetic composition 1

15 parts by mass of an epoxy resin a ("ZX-1059", a mixture of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, manufactured by Nippon iron chemical Co., Ltd.), 5 parts by mass of an epoxy resin b ("ZX-1658 GS", liquid 1, 4-glycidylcyclohexane, manufactured by Nippon iron chemical Co., Ltd.), and a curing accelerator a ("2 MZA-PW", an imidazole-based curing agentAccelerant, product of four chemical industries, Ltd.) 1 part by mass, magnetic powder a (product of EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC 1", D₅₀: 25 μm)40 parts by mass, and magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINE NC 1", D₅₀:3 μm) was mixed by 60 parts by mass to prepare a magnetic composition 1.

< example 2: preparation of magnetic composition 2

In example 1, magnetic powder a (Fe-based nanocrystalline magnetic material, "KUAMET NC 1", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed to 40 parts by mass of magnetic powder B (EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET 6B 2", D₅₀: 25 μm)40 parts by weight of a magnetic powder c (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "ATFINE NC 1", D)₅₀:3 μm)60 parts by mass of a magnetic powder D (EPSON ATMIX, Fe-based amorphous magnetic material, "AW 02-08PF 3F", D₅₀:3 μm)60 parts by mass;

in the same manner as in example 1 except for the above matters, magnetic composition 2 was prepared.

< example 3: preparation of magnetic composition 3

In example 1, magnetic powder c (a Fe-based nanocrystalline magnetic material, "ATFINE NC 1", D, manufactured by EPSON ATMIX corporation)₅₀:3 μm)60 parts by mass of a magnetic powder D (EPSON ATMIX, Fe-based amorphous magnetic material, "AW 02-08PF 3F", D₅₀:3 μm)60 parts by mass;

except for the above, magnetic composition 3 was prepared in the same manner as in example 1.

< example 4: preparation of magnetic composition 4

In example 1, magnetic powder a (Fe-based nanocrystalline magnetic material, "KUAMET NC 1", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed to 40 parts by mass of magnetic powder B (EPSON ATMIX, Fe-based amorphous magnetic material, "KUAMET 6B 2", D₅₀: 25 μm)40 parts by mass;

in the same manner as in example 1 except for the above matters, a magnetic composition 4 was prepared.

< example 5: preparation of magnetic composition 5

1.5 parts by mass of an epoxy resin a ("ZX-1059", a mixture of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, manufactured by Nippon iron chemical Co., Ltd.), 0.5 part by mass of an epoxy resin B ("ZX-1658 GS", liquid 1, 4-glycidylcyclohexane, manufactured by Nippon iron chemical Co., Ltd.), 0.1 part by mass of a curing accelerator a ("2 MZA-PW", an imidazole-based curing accelerator, manufactured by Nippon iron chemical Co., Ltd.), and a magnetic powder B (manufactured by EPSON ATMIX, a Fe-based amorphous magnetic material, "KUAME 6B 2", D₅₀: 25 μm)30 parts by mass, and magnetic powder D (EPSON ATMIX, Fe-based amorphous magnetic material, "AW 02-08PF 3F", D₅₀:3 μm) was mixed by 70 parts by mass to prepare a magnetic composition 5.

< example 6: preparation of magnetic composition 6

In example 5, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 30 parts by mass to 25 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) was changed from 70 parts by mass to 75 parts by mass;

in the same manner as in example 5 except for the above matters, magnetic composition 6 was prepared.

< example 7: preparation of magnetic composition 7

In example 5, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 30 parts by mass to 40 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) was changed from 70 parts by mass to 60 parts by mass;

in the same manner as in example 5 except for the above matters, magnetic composition 7 was prepared.

< example 8: preparation of magnetic composition 8

In example 5, magnetic powder was usedB (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 30 parts by mass to 50 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) was changed from 70 parts by mass to 50 parts by mass;

in the same manner as in example 5 except for the above matters, a magnetic composition 8 was prepared.

< example 9: preparation of magnetic composition 9

In example 5, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 30 parts by mass to 80 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) to 70 parts by mass of a magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC 1", D₅₀: 25 μm)20 parts by mass;

in the same manner as in example 5 except for the above matters, magnetic composition 9 was prepared.

< example 10: preparation of magnetic composition 10

In example 5, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 30 parts by mass to 45 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) to 70 parts by mass of a magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC 1", D₅₀: 25 μm)55 parts by mass;

in the same manner as in example 5 except for the above matters, the magnetic composition 10 was prepared.

< comparative example 1: preparation of magnetic composition 11

In example 1, magnetic powder a (Fe-based nanocrystalline magnetic material, "KUAMET NC 1", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) ofThe amount was changed from 40 parts by mass to 100 parts by mass,

no magnetic powder c (Fe-based nanocrystalline magnetic Material, "ATFINE NC 1", D, manufactured by EPSON ATMIX Co., Ltd.)₅₀:3 μm)60 parts by mass;

in the same manner as in example 1 except for the above matters, a magnetic composition 11 was prepared.

Comparative example 2: preparation of magnetic composition 12

In example 1, magnetic powder c (a Fe-based nanocrystalline magnetic material, "ATFINE NC 1", D, manufactured by EPSON ATMIX corporation)₅₀:3 μm) was changed from 60 parts by mass to 100 parts by mass,

no magnetic powder a (Fe-based nanocrystalline magnetic Material, "KUAMETNC 1", manufactured by EPSON ATMIX Co., Ltd.), D₅₀: 25 μm)40 parts by mass;

in the same manner as in example 1 except for the above matters, a magnetic composition 12 was prepared.

< comparative example 3: preparation of magnetic composition 13

In example 2, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 40 parts by mass to 100 parts by mass,

no magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX Co., Ltd.), D₅₀:3 μm)60 parts by mass;

in the same manner as in example 2 except for the above matters, magnetic composition 13 was prepared.

< comparative example 4: preparation of magnetic composition 14

In example 2, magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) was changed from 60 parts by mass to 100 parts by mass,

magnetic powder B (available from EPSON ATMIX, Fe-based amorphous magnetic Material, "KUAMET 6B 2", D) was not used₅₀: 25 μm)40 parts by mass;

in the same manner as in example 2 except for the above matters, the magnetic composition 14 was prepared.

< comparative example 5: preparation of magnetic composition 15

In example 2, magnetic powder B (Fe-based amorphous magnetic material, "KUAMET 6B 2", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 40 parts by mass to 60 parts by mass,

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) was changed from 60 parts by mass to 40 parts by mass;

in the same manner as in example 2 except for the above matters, a magnetic composition 15 was prepared.

< comparative example 6: preparation of magnetic composition 16

In example 1, magnetic powder a (Fe-based nanocrystalline magnetic material, "KUAMET NC 1", manufactured by EPSON ATMIX, Inc.; D)₅₀: 25 μm) was changed from 40 parts by mass to 60 parts by mass,

magnetic powder c (Fe-based nanocrystalline magnetic material, "ATFINE NC 1", D, manufactured by EPSON ATMIX corporation)₅₀:3 μm) was changed from 60 parts by mass to 40 parts by mass;

in the same manner as in example 1 except for the above matters, a magnetic composition 16 was prepared.

Comparative example 7: preparation of magnetic composition 17

magnetic powder D (Fe-based amorphous magnetic material, "AW 02-08PF 3F", manufactured by EPSON ATMIX, Inc.)₅₀:3 μm) to 70 parts by mass of a magnetic powder a (manufactured by EPSON ATMIX, Fe-based nanocrystalline magnetic material, "KUAMET NC 1", D₅₀: 25 μm)60 parts by mass;

in the same manner as in example 5 except for the above matters, magnetic composition 17 was prepared.

< measurement of particle size distribution of component (A) >

The magnetic powder was dispersed in pure water by ultrasonic waves to prepare a measurement sample. For the measurement of the sample, a laser diffraction scattering method was usedParticle size distribution measuring apparatus ("MT 3000 II" manufactured by MicrotracBEL Co., Ltd.), and measurement D₁₀、D₅₀And D₉₀。

< measurement of relative magnetic permeability and magnetic loss >

As a support, a polyethylene terephthalate (PET) film (PET 501010 manufactured by Lindelco, Inc.; thickness: 50 μm) treated with a silicon-based release agent was prepared. On the release surface of the PET film, each of the magnetic compositions 1 to 17 was uniformly applied by a doctor blade so that the thickness of the magnetic composition layer after drying became 100 μm, to obtain a magnetic sheet. The magnetic sheet thus obtained was heated at 190 ℃ for 90 minutes to thermally cure the magnetic composition layer, and the support was peeled off to obtain a sheet-like cured product. The resulting cured product was cut into test pieces having a width of 5mm and a length of 18mm, and the test pieces were used as evaluation samples. For the evaluation sample, the relative permeability (μ') and its imaginary component (μ ") were measured at room temperature and 23 ℃ using 3-turn coil method using Agilent Technologies," HP8362B ", and the magnetic loss was calculated from μ"/μ ".

The relative permeability was evaluated according to the following criteria;

good: relative magnetic permeability of 17 or more

And (delta): a relative magnetic permeability of 15 or more and less than 17

X: the relative magnetic permeability is less than 15.

Further, magnetic loss was evaluated according to the following criteria;

good: magnetic loss less than 0.05

And (delta): magnetic loss of 0.05 or more and less than 0.08

X: the magnetic loss is 0.08 or more.

[ Table 1]

(Table 1)

[ Table 2]

(Table 2)

It is known that D is a component (A)₁₀、D₅₀And D₉₀Examples 1 to 10 within the predetermined range have excellent relative permeability and reduced magnetic loss as compared with comparative examples 1 to 7.

[ description of symbols ]

10-core substrate

11 supporting substrate

12 first metal layer

13 second metal layer

14 through hole

20 coating

30a magnetic composition

30 magnetic layer

40 conductive layer

41 pattern conductor layer

100 circuit board

200 inner layer substrate

200a first major surface

200b second major surface

220 through hole

220a via in-wiring

240 external terminal

300 magnetic part

310 magnetic sheet material

320a magnetic composition layer

320 first insulating layer

330 support

340 second insulating layer

360 through hole

360a through-hole inner wiring

400 coil-shaped conductive structure

420 first conductor layer

420a bonding pad

440 second conductor layer.

Claims

1. A magnetic composition comprising (A) a magnetic powder and (B) a binder resin,

wherein the component (A) has a particle diameter (D) of 10% in the particle diameter distribution₁₀) Has a particle diameter (D) of 50% of 1.7-2.6 μm₅₀) Has a particle diameter (D) of 3.6-12.0 μm and 90%₉₀) Is 25.0 to 51.0 μm in diameter.

2. The magnetic composition according to claim 1, wherein the component (a) is a soft magnetic powder.

3. The magnetic composition according to claim 1, wherein the component (a) is any of a nanocrystalline magnetic material and an amorphous magnetic material.

4. The magnetic composition according to claim 1, wherein the component (a) contains a ferrous alloy-based metal powder.

5. The magnetic composition according to claim 1, wherein the component (a) is any of an Fe-based nanocrystalline magnetic material and an Fe-based amorphous magnetic material.

6. The magnetic composition of claim 1, used to form an inductor element.

7. The magnetic composition of claim 1, which is paste-like.

8. The magnetic composition of claim 1 for filling a via.

9. A magnetic sheet, comprising:

a support, and

a magnetic composition layer formed of the magnetic composition according to any one of claims 1 to 8 provided on the support.

10. A circuit board comprising a magnetic layer which is a cured product of the magnetic composition according to any one of claims 1 to 8.

11. A circuit board includes:

a substrate having a through-hole, and

a cured product of the magnetic composition according to any one of claims 1 to 8 filled in the through-hole.

12. An inductor substrate comprising the circuit substrate of claim 10 or 11.