JP7423896B2 - Substrate manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a substrate in which a conductive layer is formed by wet plating on a magnetic layer containing magnetic powder.

Inductors, sometimes called power inductors, high-frequency band inductors, and common mode choke coils, are installed in many information terminals such as mobile phones and smartphones. In the past, independent inductor components were mounted on a circuit board, but in recent years, a method has been used in which a coil is formed using a conductor pattern on the circuit board and an inductor is provided inside the circuit board.

For example, Patent Document 1 discloses that a spiral conductor pattern wound multiple times is formed in multiple layers of a multilayer board, and the ends of the conductor pattern of each layer are interlayer connected to the upper and lower layers to form a spiral coil as a whole. , a multilayer circuit board with a built-in inductor is disclosed. Moreover, Patent Document 2 discloses that an inductor board is built into a core board of a circuit board in order to make the circuit board thinner.

When manufacturing an inductor substrate in which an inductor is formed by a plurality of conductor patterns formed on an insulating layer in this way, it is possible to use a resin composition containing magnetic powder as a material for forming the insulating layer. . If an insulating layer (magnetic layer) containing magnetic powder is used, the inductance value can be increased, and leakage of magnetic lines of force to the outside of the inductor can also be suppressed. For example, Patent Document 2 discloses that a resin composition constituting a resin composition layer of a resin sheet with a support contains magnetic powder, and the formed insulating layer is made of a magnetic material.

Further, for example, Patent Document 3 discloses that a through hole in a circuit board for an inductor component is filled with a resin composition containing magnetic powder to form a magnetic core, and a wiring layer of the circuit board is formed. An inductor board is disclosed that achieves a small size and high inductance by arranging the magnetic core at the center of a coil.

Japanese Patent Application Publication No. 2009-16504 Japanese Patent Application Publication No. 2012-186440 Japanese Patent Application Publication No. 2016-197624

In manufacturing these inductor substrates, a conductor layer is sometimes formed on a magnetic layer containing magnetic powder, and it is desirable to form the conductor layer by wet plating, which is advantageous in terms of cost.

When forming a conductor layer on an insulating layer that does not contain magnetic powder, a common method is to treat the surface of the insulating layer with an oxidizing agent and then form the conductor layer. However, as a result of intensive research by the present inventors, when forming a conductor layer on a magnetic layer containing magnetic powder, when the surface of the magnetic layer is treated with an oxidizing agent, the resin and magnetic powder are eluted, and the magnetic layer is It has been found that it is difficult to achieve good plating adhesion because the plating becomes brittle.

For this reason, the present inventors investigated a method of forming a conductor layer by polishing the surface of the magnetic layer as a process for forming a conductor layer on the magnetic layer without using an oxidizing agent. However, when a conductor layer was formed on the magnetic layer by wet plating after polishing the surface of the magnetic layer, during the wet plating process, precipitates that were thought to originate from the magnetic powder contained in the magnetic layer were formed. A new problem was discovered in that magnetic foreign substances such as carbon and precipitates are generated and contaminate baths, substrates, etc. In particular, it has been found that when electroless plating is performed, contamination becomes noticeable in the catalyst activation step in which a catalyst such as palladium is applied to the surface of the magnetic layer and then activated with a reducing agent.

The present invention has been made in view of the above circumstances, and is capable of suppressing contamination of baths and substrates in manufacturing a substrate in which a conductive layer is formed by wet plating on a magnetic layer containing magnetic powder. The purpose of the present invention is to provide a method for manufacturing a substrate.

In order to achieve the above object, the present inventors have conducted extensive studies and found that by removing magnetic foreign matter using the magnetic force of a magnet before wet plating, the present inventors have discovered that magnetic foreign matter derived from magnetic powder in wet plating can be removed by removing magnetic foreign matter using the magnetic force of a magnet before wet plating. They discovered that contamination can be suppressed and completed the present invention.

That is, the present invention includes the following contents.
[1] A method for manufacturing a substrate in which a conductor layer is formed by wet plating on a magnetic layer containing magnetic powder, the method comprising:
(A-i) immersing the magnetic layer in a liquid contained in a liquid bath; and (A-ii) removing magnetic foreign matter generated in the liquid using magnetic force. Production method.
[2] The method for manufacturing a substrate according to [1], wherein in the step (A-ii), magnetic foreign matter is generated from the magnetic layer.
[3] The method for manufacturing a substrate according to [1] or [2], wherein the magnetic foreign material contains at least one selected from Fe, Co, Ni, and Mn.
[4] The method for manufacturing a substrate according to any one of [1] to [3], wherein the magnetic foreign material contains at least one selected from Fe and Mn.
[5] The method for manufacturing a substrate according to any one of [1] to [4], wherein the magnetic foreign substance contains Fe.
[6] The method for manufacturing a substrate according to any one of [1] to [5], wherein the source of magnetic force is located inside the liquid bath.
[7] The method for manufacturing a substrate according to any one of [1] to [6], wherein the source of the magnetic force is located outside the liquid bath.
[8] After the steps (A-i) and (A-ii), any one of [1] to [7] includes (B) a step of forming a conductor layer on the magnetic layer by wet plating. A method of manufacturing the described substrate.
[9] The method for manufacturing a substrate according to [8], in which the step (B) performs electroless plating to form a conductor layer.
[10] The method for manufacturing a substrate according to [8] or [9], in which the step (B) performs electroless copper plating to form a conductor layer.
[11] The method for manufacturing a substrate according to any one of [8] to [10], wherein in step (B), after performing electroless plating treatment, further electrolytic plating treatment is performed to form a conductor layer.
[12] Before step (A-i) and step (A-ii),
The method for manufacturing a substrate according to any one of [1] to [11], further comprising: (a) polishing the surface of the magnetic layer.
[13] The method for manufacturing a substrate according to any one of [1] to [12], wherein the substrate is an inductor substrate having an inductor element formed of a patterned conductor layer.
[14] The method for manufacturing a substrate according to any one of [1] to [13], wherein the magnetic layer is formed by curing a resin composition containing magnetic powder and a binder resin.
[15] The method for manufacturing a substrate according to [14], wherein the binder resin contains a thermosetting resin.
[16] The method for manufacturing a substrate according to [15], wherein the thermosetting resin is an epoxy resin.
[17] The magnetic powder according to any one of [14] to [16], wherein the content of the magnetic powder is 70% by mass or more and 98% by mass or less when the nonvolatile component in the resin composition is 100% by mass. Substrate manufacturing method.
[18] The method for manufacturing a substrate according to any one of [14] to [17], wherein the resin composition is a paste-like resin composition.
[19] The method for manufacturing a substrate according to any one of [1] to [18], wherein the magnetic powder is at least one selected from iron oxide powder and iron alloy metal powder.
[20] Any one of [1] to [19], wherein the magnetic powder contains iron oxide powder, and the iron oxide powder contains ferrite containing at least one selected from Ni, Cu, Mn, and Zn. A method of manufacturing the described substrate.
[21] Manufacture of the substrate according to any one of [1] to [20], wherein the magnetic powder contains iron alloy metal powder containing at least one selected from Si, Cr, Al, Ni, and Co. Method.

According to the present invention, it is possible to provide a method for manufacturing a substrate that can suppress contamination due to the generation of magnetic foreign matter originating from magnetic powder in a magnetic layer during wet plating.

FIG. 1 is a schematic cross-sectional view of a core substrate as an example of a first embodiment of a method for manufacturing a substrate. FIG. 2 is a schematic cross-sectional view of a core substrate in which through holes are formed as an example of the first embodiment of the substrate manufacturing method. FIG. 3 is a schematic cross-sectional view showing how a plating layer is formed in a through hole as an example of the first embodiment of the substrate manufacturing method. FIG. 4 is a schematic cross-sectional view showing how through-hole filling paste is filled into through-holes as an example of the first embodiment of the substrate manufacturing method. FIG. 5 is a schematic cross-sectional view showing a cured product obtained by thermosetting the filled through-hole filling paste as an example of the first embodiment of the substrate manufacturing method. FIG. 6 is a schematic cross-sectional view showing the state after polishing the cured product as an example of the first embodiment of the substrate manufacturing method. FIG. 7 is a schematic cross-sectional view showing a state in which a conductive layer is formed on a polished surface as an example of the first embodiment of the method for manufacturing a substrate. FIG. 8 is a schematic cross-sectional view showing how a patterned conductor layer is formed as an example of the first embodiment of the substrate manufacturing method. FIG. 9 is a schematic cross-sectional view for explaining the (α-1) step as an example of the second embodiment of the substrate manufacturing method. FIG. 10 is a schematic cross-sectional view for explaining the (α-1) step as an example of the second embodiment of the substrate manufacturing method. FIG. 11 is a schematic cross-sectional view for explaining the (α-2) step as an example of the second embodiment of the substrate manufacturing method. FIG. 12 is a schematic cross-sectional view showing how a patterned conductor layer is formed as an example of the second embodiment of the substrate manufacturing method. FIG. 13 is a schematic plan view of an inductor component including a substrate obtained by the second embodiment of the substrate manufacturing method as an example, viewed from one side in the thickness direction. FIG. 14 is a schematic diagram showing a cut end surface of an inductor component including a substrate obtained by the second embodiment of the method for manufacturing a substrate, which is cut at the position indicated by the dashed line II-II as an example. FIG. 15 is a schematic plan view for explaining the configuration of the first conductor layer of the inductor component including the substrate obtained by the second embodiment of the substrate manufacturing method as an example.

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that each drawing merely schematically shows the shape, size, and arrangement of the constituent elements to the extent that the invention can be understood. The present invention is not limited to the following description, and each component can be changed as appropriate. In the drawings used in the following description, similar components are designated by the same reference numerals, and overlapping descriptions may be omitted. Further, the configuration according to the embodiment of the present invention is not necessarily manufactured or used according to the arrangement shown in the illustrated example.

In the manufacturing method of the present invention, a substrate including a magnetic layer and a conductive layer is manufactured. A substrate manufactured in this manner may be hereinafter referred to as a "product substrate." Before explaining the method for manufacturing this product substrate, the resin composition that can form the magnetic layer will be explained.

[Resin composition]
The resin composition includes (a) magnetic powder and (b) binder resin. The resin composition may further contain (c) a dispersant, (d) a curing accelerator, and (e) other additives, if necessary.

<(a) Magnetic powder>
The resin composition contains (a) magnetic powder. (a) Examples of the magnetic powder include pure iron powder; Mg-Zn ferrite, Fe-Mn ferrite, Mn-Zn ferrite, Mn-Mg ferrite, Cu-Zn ferrite, Mg-Mn-Sr. ferrite, Ni-Zn ferrite, Ba-Zn ferrite, Ba-Mg ferrite, Ba-Ni ferrite, Ba-Co ferrite, Ba-Ni-Co ferrite, Y ferrite, iron oxide powder (III ), iron oxide powder such as triiron tetroxide; Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy powder, Fe-Ni-Cr alloy powder. Alloy powder, Fe-Cr-Al alloy powder, Fe-Ni alloy powder, Fe-Ni-Mo alloy powder, Fe-Ni-Mo-Cu alloy powder, Fe-Co alloy powder, or Fe-Ni - Iron alloy metal powders such as Co-based alloy powder; amorphous alloys such as Co-based amorphous.

Among these, (a) magnetic powder is preferably at least one selected from iron oxide powder and iron alloy metal powder. The iron oxide powder preferably contains ferrite containing at least one selected from Ni, Cu, Mn, and Zn. Further, the iron alloy metal powder preferably includes an iron alloy metal powder containing at least one selected from Si, Cr, Al, Ni, and Co.

(a) As the magnetic powder, commercially available magnetic powder can be used. Specific examples of commercially available magnetic powders that can be used include "M05S" manufactured by Powder Tech; "PST-S" manufactured by Sanyo Special Steel; "AW2-08" and "AW2-08PF20F" manufactured by Epson Atomics; "AW2-08PF10F", "AW2-08PF3F", "Fe-3.5Si-4.5CrPF20F", "Fe-50NiPF20F", "Fe-80Ni-4MoPF20F"; JFE Chemical "LD-M", "LD -MH", "KNI-106", "KNI-106GSM", "KNI-106GS", "KNI-109", "KNI-109GSM", "KNI-109GS"; "KNS-415" manufactured by Toda Kogyo Co., Ltd. "BSF-547", "BSF-029", "BSN-125", "BSN-125", "BSN-714", "BSN-828", "S-1281", "S-1641", "S -1651", "S-1470", "S-1511", "S-2430"; "JR09P2" manufactured by Japan Heavy Chemical Industry Co., Ltd.; "Nanotek" manufactured by CIK Nanotech; "JEMK-S" manufactured by Kinseimatec, " JEMK-H": "Yttrium iron oxide" manufactured by ALDRICH, etc. One type of magnetic powder may be used alone, or two or more types may be used in combination.

(a) The magnetic powder is preferably spherical. The value obtained by dividing the length of the long axis of the magnetic powder by the length of the short axis (aspect ratio) is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. In general, the relative magnetic permeability of magnetic powder can be improved more easily when the magnetic powder has a flat shape rather than a spherical shape. However, it is generally preferable to use spherical magnetic powder from the viewpoint of lowering magnetic loss and obtaining a paste having a preferable viscosity.

(a) The average particle size of the magnetic powder is preferably 0.01 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more, from the viewpoint of improving relative magnetic permeability. Moreover, it is preferably 10 μm or less, more preferably 9 μm or less, and still more preferably 8 μm or less.

(a) The average particle size of the magnetic powder can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of the magnetic powder on a volume basis using a laser diffraction scattering type particle size distribution measuring device, and using the median diameter as the average particle size. As the measurement sample, one in which magnetic powder is dispersed in water using ultrasonic waves can be preferably used. As the laser diffraction scattering particle size distribution measuring device, "LA-500" manufactured by Horiba, "SALD-2200" manufactured by Shimadzu Corporation, etc. can be used.

(a) The specific surface area of the magnetic powder is preferably 0.05 m ² /g or more, more preferably 0.1 m ² /g or more, and even more preferably 0.3 m ² /g from the viewpoint of improving relative magnetic permeability. That's all. Moreover, it is preferably 10 m ² /g or less, more preferably 8 m ² /g or less, and still more preferably 5 m ² /g or less. (a) The specific surface area of magnetic powder can be measured by the BET method.

(a) The content (volume %) of the magnetic powder is preferably 40 volume % when the nonvolatile component in the resin composition is 100 volume %, from the viewpoint of improving the relative magnetic permeability and reducing the loss coefficient. The content is more preferably 45% by volume or more, still more preferably 50% by volume or more. Further, it is preferably 90% by volume or less, more preferably 80% by volume or less, even more preferably 75% by volume or less.

(a) The content (mass%) of the magnetic powder is preferably 70% by mass when the nonvolatile component in the resin composition is 100% by mass, from the viewpoint of improving the relative magnetic permeability and reducing the loss coefficient. The content is more preferably 75% by mass or more, still more preferably 80% by mass or more. Moreover, it is preferably 98% by mass or less, more preferably 97% by mass or less, and still more preferably 95% by mass or less.

<(b) Binder resin>
The resin composition contains (b) a binder resin. (b) The binder resin is not particularly limited as long as it is a resin that can form a magnetic layer by dispersing and bonding the (a) magnetic powder in the resin composition.

(b) Examples of the binder resin include epoxy resin, phenol resin, naphthol resin, benzoxazine resin, active ester resin, cyanate ester resin, carbodiimide resin, amine resin, acid anhydride resin, etc. Thermosetting resins include thermoplastic resins such as phenoxy resins, acrylic resins, polyvinyl acetal resins, butyral resins, polyimide resins, polyamideimide resins, polyethersulfone resins, and polysulfone resins. (b) As the binder resin, it is preferable to use a thermosetting resin used when forming an insulating layer of a wiring board, and among them, an epoxy resin is preferable. (b) The binder resin may be used alone or in combination of two or more.
Here, phenol resins, naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins react with epoxy resins. Components that can cure a resin composition are sometimes collectively referred to as a "curing agent."

-Thermosetting resin-
Epoxy resins as thermosetting resins include, for example, glycyol type epoxy resin; bisphenol A type epoxy resin; bisphenol F type epoxy resin; bisphenol S type epoxy resin; bisphenol AF type epoxy resin; dicyclopentadiene type epoxy resin; trisphenol. type epoxy resin; phenol novolac type epoxy resin; tert-butyl-catechol type epoxy resin; epoxy resin having a condensed ring structure such as naphthol novolac type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin; glycidyl Amine type epoxy resin; glycidyl ester type epoxy resin; cresol novolak type epoxy resin; biphenyl type epoxy resin; linear aliphatic epoxy resin; epoxy resin with butadiene structure; alicyclic epoxy resin; heterocyclic epoxy resin; spiro ring Containing epoxy resins; cyclohexanedimethanol type epoxy resins; trimethylol type epoxy resins; tetraphenylethane type epoxy resins and the like. Epoxy resins may be used alone or in combination of two or more. The epoxy resin is preferably one or more selected from bisphenol A epoxy resins and bisphenol F epoxy resins.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. Moreover, it is preferable that the epoxy resin has an aromatic structure, and when two or more types of epoxy resins are used, it is more preferable that at least one type has an aromatic structure. The aromatic structure is a chemical structure that is generally defined as aromatic, and also includes polycyclic aromatics and aromatic heterocycles. The proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, particularly preferably 70% by mass, relative to 100% by mass of the nonvolatile components of the epoxy resin. % or more.

Epoxy resins include epoxy resins that are liquid at a temperature of 25°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 25°C (hereinafter sometimes referred to as "solid epoxy resins"). ). (b) When containing an epoxy resin as a component, 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. However, from the viewpoint of preventing the viscosity of the resin composition from becoming too high and making it easier to form into a paste when a large amount of magnetic powder is contained in order to increase the relative magnetic permeability, liquid epoxy resin is used. It is preferable to include only

Liquid epoxy resins include glycyol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, and phenol novolac type epoxy resin. Preferred are resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol type epoxy resins, and epoxy resins having a butadiene structure, and more preferred are glycyol type epoxy resins, bisphenol A type epoxy resins, and bisphenol F type epoxy resins. Specific examples of liquid epoxy resins include "HP4032", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC; "828US", "jER828EL" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation. , "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin); "630", "630LSD" manufactured by Mitsubishi Chemical Corporation, "ED-523T" manufactured by ADEKA (glycylol type epoxy resin) (Adeka Glycilol)), “EP-3980S” (glycidylamine type epoxy resin), “EP-4088S” (dicyclopentadiene type epoxy resin); “ZX1059” (bisphenol A type epoxy resin) manufactured by Nippon Steel Chemical & Materials mixture of resin and bisphenol F type epoxy resin), “EX-201” (cycloaliphatic glycidyl ether), “ZX1658”, “ZX1658GS” (liquid 1,4-glycidylcyclohexane); “EX” manufactured by Nagase ChemteX Examples include "Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton) and "PB-3600" (epoxy resin having a butadiene structure) manufactured by Daicel. These may be used alone or in combination of two or more.

Solid epoxy resins include naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, Anthracene-type epoxy resins, bisphenol A-type epoxy resins, and tetraphenylethane-type epoxy resins are preferred, and naphthalene-type tetrafunctional epoxy resins, naphthol-type epoxy resins, and biphenyl-type epoxy resins are more preferred. Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), and "N-690" (manufactured by DIC). Cresol novolak type epoxy resin), “N-695” (cresol novolac type epoxy resin), “HP-7200”, “HP-7200HH”, “HP-7200H” (dicyclopentadiene type epoxy resin), “EXA-7311” ", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" manufactured by Nippon Kayaku Co., Ltd. Trisphenol type epoxy resin), “NC7000L” (naphthol novolac type epoxy resin), “NC3000H”, “NC3000”, “NC3000L”, “NC3100” (biphenyl type epoxy resin); “ESN475V” manufactured by Nippon Steel Chemical & Materials ” (naphthalene type epoxy resin), “ESN485” (naphthol novolac type epoxy resin); Mitsubishi Chemical's “YX4000H”, “YL6121” (biphenyl type epoxy resin), “YX4000HK” (bixylenol type epoxy resin), “ "YX8800" (anthracene type epoxy resin); "PG-100", "CG-500" manufactured by Osaka Gas Chemical Company, "YL7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd. resin), "jER1010" (solid bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin), and the like. These may be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used together as the component (b), their quantitative ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1: 4, more preferably 1:0.3 to 1:3.5, even more preferably 1:0.6 to 1:3.

The epoxy equivalent of the epoxy resin as component (b) is preferably 50 g/eq. ～5000g/eq. , more preferably 50g/eq. ～3000g/eq. , more preferably 80g/eq. ～2000g/eq. , even more preferably 110 g/eq. ～1000g/eq. It is. By falling within this range, the crosslinking density of the cured product will be sufficient and a magnetic layer with small surface roughness can be provided. Note that the epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of epoxy group.

The weight average molecular weight of the epoxy resin as component (b) is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. Here, the weight average molecular weight of the epoxy resin is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) method.

As the active ester resin, a resin having one or more active ester groups in one molecule can be used. Among these, active ester resins include those having two or more ester groups with high reaction activity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Resins are preferred. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound are more preferred.

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

Examples of phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, 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, phloroglucin, Examples include benzenetriol, dicyclopentadiene type diphenol compounds, and phenol novolacs. Here, the term "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Preferred specific examples of active ester resins include active ester resins containing a dicyclopentadiene type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated product of phenol novolak, and benzoyl phenol novolac. Examples include active ester resins containing compounds. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester resins include "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," and "HPC-8000H-" as active ester resins containing a dicyclopentadiene diphenol structure. 65TM", "EXB-8000L-65TM" (manufactured by DIC Corporation); "EXB9416-70BK", "EXB-8150-65T" (manufactured by DIC Corporation); an acetylated product of phenol novolak as an active ester resin containing a naphthalene structure; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing a benzoylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing a benzoylated product of phenol novolak; "DC808" (manufactured by Mitsubishi Chemical); "YLH1026" (manufactured by Mitsubishi Chemical), "YLH1030" (manufactured by Mitsubishi Chemical), "YLH1048" (manufactured by Mitsubishi Chemical) as active ester resins that are benzoylated products of phenol novolak ); etc.

As the phenol resin and naphthol resin, those having a novolac structure are preferable from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenolic curing agent is preferred, and a triazine skeleton-containing phenolic resin is more preferred.

Specific examples of phenolic resins and naphthol resins include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and "NHN" and "CBN" manufactured by Nippon Kayaku Co., Ltd. ", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", "SN375", "SN395" manufactured by Nippon Steel Chemical & Materials ", "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

Specific examples of benzoxazine resins include JFE Chemical's "JBZ-OD100" (benzoxazine ring equivalent: 218), "JBZ-OP100D" (benzoxazine ring equivalent: 218), and "ODA-BOZ" (benzoxazine ring equivalent: 218). "P-d" (benzoxazine ring equivalent 217), "Fa" (benzoxazine ring equivalent 217) manufactured by Shikoku Kasei Kogyo Co., Ltd.; "HFB2006M" manufactured by Showa Kobunshi Co., Ltd. (benzoxazine ring equivalent 217); 432), etc.

Examples of cyanate ester resins include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), and 4,4' -ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanato)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanato-3,5-dimethylphenyl) ) Difunctional cyanate resins such as methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether; phenol Polyfunctional cyanate resins derived from novolacs, cresol novolacs, etc.; prepolymers in which these cyanate resins are partially triazinized; and the like. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolak type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin), and "BA230" manufactured by Lonza Japan. Examples include "BA230S75" (a prepolymer in which part or all of bisphenol A dicyanate is triazinized to form a trimer).

Specific examples of carbodiimide-based resins include Carbodilite (registered trademark) V-03 (carbodiimide group equivalent: 216), V-05 (carbodiimide group equivalent: 262), V-07 (carbodiimide group equivalent: 200) manufactured by Nisshinbo Chemical Co., Ltd. ); V-09 (carbodiimide group equivalent: 200); Stabaxole (registered trademark) P manufactured by Rhein Chemie (carbodiimide group equivalent: 302).

Examples of the amine resin include resins having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Among them, aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of the amine curing agent include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 3,3' - Diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl- 4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethane Diamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3- Bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, Examples include bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine resins may be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYA HARD AA", "KAYA HARD AB", and "KAYA HARD" manufactured by Nippon Kayaku Co., Ltd. Examples include "A-S" and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

Examples of the acid anhydride resin include resins having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride resins include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and hydrogenated methylnadic anhydride. trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride Acid, pyromellitic anhydride, bensophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl Sulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1, Examples include polymeric acid anhydrides such as 3-dione, ethylene glycol bis(anhydrotrimellitate), and styrene-maleic acid resin, which is a copolymer of styrene and maleic acid.

When containing an epoxy resin and a curing agent as components (b), the ratio of the epoxy resin to all curing agents is [total number of epoxy groups in the epoxy resin]:[total number of reactive groups in the curing agent]. The ratio is preferably in the range of 1:0.01 to 1:5, more preferably 1:0.5 to 1:3, and even more preferably 1:1 to 1:2. Here, "the number of epoxy groups in the epoxy resin" is the sum of all the values obtained by dividing the mass of nonvolatile components of the epoxy resin present in the resin composition by the epoxy equivalent. Moreover, "the number of active groups of a curing agent" is the total value of all the values obtained by dividing the mass of nonvolatile components of the curing agent present in the resin composition by the active group equivalent.

-Thermoplastic resin-
The weight average molecular weight of the thermoplastic resin in terms of polystyrene is preferably 30,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. Further, it is preferably 1,000,000 or less, more preferably 750,000 or less, and still more preferably 500,000 or less. The weight average molecular weight of the thermoplastic resin in terms of polystyrene is measured by gel permeation chromatography (GPC). Specifically, the weight average molecular weight of the thermoplastic resin in terms of polystyrene was determined using "LC-9A/RID-6A" manufactured by Shimadzu Corporation as a measuring device and "Shodex K-800P/K-804L" manufactured by Showa Denko Co. as a column. /K-804L'' using chloroform or the like as a mobile phase at a column temperature of 40°C, and can be calculated using a standard polystyrene calibration curve.

Examples of phenoxy resins include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, and terpene. Examples include phenoxy resins having one or more types of skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. One type of phenoxy resin may be used alone, or two or more types may be used in combination. Specific examples of phenoxy resins include Mitsubishi Chemical's "1256" and "4250" (both phenoxy resins containing bisphenol A skeleton), "YX8100" (phenoxy resin containing bisphenol S skeleton), and "YX6954" (bisphenol acetophenone). Other examples include "FX280" and "FX293" manufactured by Nippon Steel Chemical & Materials, "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30" manufactured by Mitsubishi Chemical Corporation, Examples include "YL7769BH30", "YL6794", "YL7213", "YL7290", and "YL7482".

As the acrylic resin, a functional group-containing acrylic resin is preferable from the viewpoint of further lowering the thermal expansion coefficient and elastic modulus, and an epoxy group-containing acrylic resin having a glass transition temperature of 25° C. or less is more preferable.

The number average molecular weight (Mn) of the functional group-containing acrylic resin is preferably 10,000 to 1,000,000, more preferably 30,000 to 900,000.

The functional group equivalent of the functional group-containing acrylic resin is preferably 1,000 to 50,000, more preferably 2,500 to 30,000.

As the epoxy group-containing acrylic resin with a glass transition temperature of 25°C or lower, an epoxy group-containing acrylic acid ester copolymer resin with a glass transition temperature of 25°C or lower is preferable, and a specific example thereof is "SG" manufactured by Nagase ChemteX. -80H" (epoxy group-containing acrylic ester copolymer resin (number average molecular weight Mn: 350000 g/mol, epoxy value 0.07 eq/kg, glass transition temperature 11 ° C.)), "SG-P3" manufactured by Nagase ChemteX (Epoxy group-containing acrylic ester copolymer resin (number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg, glass transition temperature 12° C.)).

Specific examples of polyvinyl acetal resin and butyral resin include Denka Butyral “4000-2”, “5000-A”, “6000-C”, and “6000-EP” manufactured by Denki Kagaku Kogyo Co., Ltd., and “6000-EP” manufactured by Sekisui Chemical Co., Ltd. Examples include the S-LEC BH series, BX series, KS series such as "KS-1", BL series such as "BL-1", and BM series.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nihon Rika Co., Ltd. Specific examples of polyimide resins include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides (polyimide described in JP-A No. 2006-37083), polysiloxane skeletons, etc. Examples include modified polyimides such as polyimides containing polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-319386, etc.).

Specific examples of the polyamide-imide resin include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo. Specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical.

A specific example of the polyether sulfone resin includes "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. A specific example of the polyphenylene ether resin includes "OPE-2St 1200", an oligophenylene ether styrene resin having a vinyl group manufactured by Mitsubishi Gas Chemical Co., Ltd.

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

Among these, the thermoplastic resin is preferably one or more selected from phenoxy resins, polyvinyl acetal resins, butyral resins, and acrylic resins having a weight average molecular weight of 30,000 to 1,000,000.

(b) The content of the binder resin is determined based on the nonvolatile components in the resin composition being 100% by mass, from the viewpoint of (a) dispersing and bonding the magnetic powder in the resin composition to form a magnetic layer. , preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more. The upper limit is not particularly limited as long as the effects of the present invention can be achieved, but it is preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less.

<(c) Dispersant>
The resin composition may further contain (c) a dispersant as an optional component. (c) By using a dispersant, the dispersibility of component (a) can be improved.

(c) Dispersants include, for example, phosphate ester dispersants such as polyoxyethylene alkyl ether phosphate; anionic dispersants such as sodium dodecylbenzel sulfonate, sodium laurate, and ammonium salts of polyoxyethylene alkyl ether sulfate. Dispersant; organosiloxane dispersant, acetylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc. Examples include nonionic dispersants. Among these, anionic dispersants are preferred. One type of dispersant may be used alone, or two or more types may be used in combination.

A commercially available product can be used as the phosphate ester dispersant. Commercially available products include, for example, "RS-410", "RS-610", and "RS-710" of the "Phosphanol" series manufactured by Toho Chemical Industry Co., Ltd.

As the organosiloxane dispersant, commercially available products include BYK347 and BYK348 manufactured by BYK Chemie.

Commercially available polyoxyalkylene dispersants include "AKM-0531," "AFB-1521," "SC-0505K," "SC-1015F," and "SC-0708A" from the NOF Corporation's "Marialim" series. ”, and “HKM-50A”. Polyoxyalkylene dispersants include polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc. It is a generic term.

Acetylene glycol is commercially available from Air Products and Chemicals Inc. Examples include "82," "104," "440," "465," and "485" from the "Surfynol" series manufactured by Manufacturer Co., Ltd., and "Olefin Y."

(c) The content of the dispersant is preferably 0.1% by mass or more, more preferably 0% by mass, when the nonvolatile components in the resin composition are 100% by mass, from the viewpoint of significantly exhibiting the effects of the present invention. .2% by mass or more, more preferably 0.4% by mass or more, and the upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less.

<(d) Curing accelerator>
The resin composition may further contain (d) a curing accelerator as an optional component. (d) By using a curing accelerator, the curing of the binder resin can be effectively progressed and the mechanical strength of the cured product can be increased. (d) Examples of the curing accelerator include amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like. From the viewpoint of reducing the viscosity of the resin composition, the curing accelerator is preferably an amine curing accelerator or an imidazole curing accelerator, and more preferably an imidazole curing agent. One type of curing accelerator may be used alone, or two or more types may be used in combination.

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

As the amine curing accelerator, commercially available products may be used, such as "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine Techno.

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-Phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecyl imidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4- Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline , 2-phenylimidazoline and other imidazole compounds, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

As the imidazole curing accelerator, commercially available products may be used, such as "2MZA-PW" and "2PHZ-PW" manufactured by Shikoku Kasei Kogyo Co., Ltd., and "P200-H50" manufactured by Mitsubishi Chemical Corporation. .

Examples of the phosphorus curing accelerator include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, 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, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 -allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide, etc., and dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

Examples of the metal hardening accelerator include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. Examples include organic zinc complexes such as , 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.

(d) The curing accelerator is preferably at least one selected from amine curing accelerators and imidazole curing accelerators, and more preferably imidazole curing accelerators.

(d) From the viewpoint of lowering the viscosity of the resin composition, the content of the curing accelerator is preferably 0.1% by mass or more, more preferably 0.1% by mass or more when the nonvolatile component in the resin composition is 100% by mass. It is 2% by mass or more, more preferably 0.3% by mass or more. The upper limit is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less.

<(e) Other additives>
The resin composition may further contain (e) other additives as necessary. Examples of such other additives include curing retarders such as triethyl borate, flame retardants, thickeners, antifoaming agents, leveling agents, adhesion agents, and resin additives such as colorants. It will be done.

<Method for manufacturing resin composition>
The resin composition can be produced, for example, by a method in which the ingredients are stirred using a stirring device such as a three-roll mixer, a rotary mixer, or a high-speed rotary mixer. The resin composition may be defoamed after manufacturing. Examples include defoaming by standing still, defoaming by centrifugation, vacuum defoaming, stirring defoaming, and combinations thereof.

In forming the magnetic layer, the resin composition may be used in the form of a paste-like resin composition (magnetic paste), or may be used in the form of a magnetic sheet containing a layer of the resin composition.

[Magnetic paste]
By using a liquid binder resin or the like, the resin composition can be made into a paste-like magnetic paste without containing an organic solvent. When the magnetic paste contains an organic solvent, the content thereof is preferably less than 1.0% by mass, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass, based on the total mass of the magnetic paste. The content is particularly preferably 0.1% by mass or less. The lower limit is not particularly limited, but is 0.001% by mass or more, or not contained. To suppress the generation of voids due to volatilization of the organic solvent by containing a small amount of organic solvent in the magnetic paste, or to have no organic solvent, and to have excellent handling and workability. Can be done.

The viscosity of the magnetic paste at 25° C. is preferably 20 Pa·s or more, more preferably 25 Pa·s or more, even more preferably 30 Pa·s or more, 40 Pa·s or more, and usually less than 200 Pa·s, preferably 180 Pa·s. It is more preferably 160 Pa·s or less. The viscosity can be measured using an E-type viscometer while maintaining the temperature of the magnetic paste at 25±2°C.

[Magnetic sheet]
The magnetic sheet includes a support and a resin composition layer formed of a resin composition provided on the support.

The thickness of the resin composition layer is preferably 250 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less, and 100 μm or less, from the viewpoint of thinning. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 5 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 preferred.

When using a film made of a plastic material as a support, examples of the plastic material include polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"). ), polyesters such as polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether Examples include ketones and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When using metal foil as the support, examples of the metal foil include copper foil, aluminum foil, etc., with copper foil being preferred. As the copper foil, a foil made of a single metal such as copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. May be used.

The support may be subjected to matte treatment or corona treatment on the surface to be bonded to the resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. . The support with a release layer may be a commercially available product, such as "SK-1" manufactured by Lintec Corporation, which is a PET film having a release layer containing an alkyd resin mold release agent as a main component. Examples include "AL-5", "AL-7", "Lumirror T60" manufactured by Toray Industries, "Purex" manufactured by Teijin, and "Unipeel" manufactured by Unitika.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. In addition, when using the support body with a mold release layer, it is preferable that the thickness of the whole support body with a mold release layer is in the said range.

For the magnetic sheet, for example, a resin varnish is prepared by dissolving a resin composition in an organic solvent, and this resin varnish is applied onto a support using a die coater or the like, and further dried to form a resin composition layer. It can be manufactured by In addition, when the resin composition is in the form of a paste, it can be manufactured by applying the resin composition directly onto the support using a die coater or the like, and further drying to form a resin composition layer.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK) and cyclohexanone, acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and butyl carbitol. Examples include carbitols, aromatic hydrocarbons such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone. One type of organic solvent may be used alone, or two or more types may be used in combination.

Drying may be performed by a known method such as heating or blowing hot air. The drying conditions are not particularly limited, but the resin composition layer is dried so that the content of the organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% to 60% by mass of organic solvent, the resin composition can be adjusted by drying at 50°C to 150°C for 3 to 10 minutes. A material layer can be formed.

In the magnetic sheet, a protective film similar to the support may be further laminated on the surface of the resin composition layer that is not bonded to the support (that is, the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed. The magnetic sheet can be wound up into a roll and stored. If the magnetic sheet has a protective film, it can be used by peeling off the protective film.

[Product board manufacturing method]
The method for manufacturing a product substrate of the present invention is a method for manufacturing a product substrate in which a conductor layer is formed by wet plating on a magnetic layer containing magnetic powder, the method comprising:
The method includes (A-i) a step of immersing the magnetic layer in a liquid contained in a liquid bath, and (A-ii) a step of removing magnetic foreign matter generated in the liquid using magnetic force.
The method for manufacturing a product substrate of the present invention includes, after the above steps (A-i) and (A-ii),
(B) The method may include a step of forming a conductor layer on the magnetic layer by wet plating.
Furthermore, in the method for manufacturing a product substrate of the present invention, before the above steps (A-i) and (A-ii),
(a) The method may include a step of polishing the surface of the magnetic layer.

When performing wet plating, the step (A-i) of immersing the magnetic layer in a suitable liquid contained in a liquid bath is usually performed. Hereinafter, the liquid in which the magnetic layer is immersed may be referred to as "immersion liquid." At this time, magnetic foreign matter may be generated in the immersion liquid. The above-mentioned magnetic foreign matter is usually generated from the magnetic layer, and more specifically, it may be generated when magnetic powder contained in the magnetic layer is eluted into the immersion liquid and then precipitated. In the present invention, (A-ii) a step of removing magnetic foreign matter generated in the liquid using magnetic force is performed. Although the order of steps (A-i) to (A-ii) is arbitrary, microscopically steps (A-i) and (A-ii) are usually performed in this order, and macroscopically, steps (A-i) and (A-ii) are performed in this order. Generally done at the same time.

Hereinafter, the significance of the above steps (A-i) to (A-ii) will be explained using specific examples. Magnetic powder, unlike inorganic fillers such as silica, has the property of being easily dissolved in components such as oxidizing agents and acids. For this reason, when the magnetic layer is immersed in an immersion liquid containing the above-mentioned components capable of dissolving magnetic powder, the magnetic powder on the surface of the magnetic layer may be eluted into the immersion liquid ((A-i ) process). Depending on the conditions of the immersion liquid, the magnetic powder eluted into the immersion liquid may precipitate after the elution described above, and as a result, magnetic foreign matter may be generated in the liquid bath. For example, in the catalyst activation process in which the magnetic layer is immersed in an acidic reducing agent solution to activate the catalyst, after the magnetic powder is eluted by the reducing agent solution, metals such as iron in the magnetic powder are reduced. A large amount of magnetic foreign matter is generated in the reducing bath. The higher the content of magnetic powder, the more magnetic foreign matter will be generated, contaminating the reduction bath, product substrates, and the like.

In addition, for example, before performing the catalyst activation process, the product substrate may be immersed in a solution containing a surfactant in order to adjust the surface charge on the magnetic layer so that the adsorption of the catalyst can be facilitated. . In addition, the product substrate may be immersed in a micro-etching solution in order to remove the surfactant from areas where the surfactant is not needed and to suppress adsorption of the catalyst to the areas where the surfactant is not needed. Furthermore, before performing the catalyst activation step, a catalyst application step may be performed in which the product substrate is immersed in a solution containing a catalyst. In these cases, when the magnetic layer is immersed in each immersion liquid (a solution containing a surfactant, a micro-etching liquid, and a solution containing a catalyst), the magnetic powder on the surface of the magnetic layer is eluted into the immersion liquid. (Step (A-i)), and as a result, magnetic foreign substances were sometimes generated in the liquid bath.

In contrast, the present invention includes the step (A-ii) of removing the magnetic foreign matter generated in the immersion liquid as described above from the immersion liquid using magnetic force. In the example using the reducing agent solution, in step (A-ii), the catalyst is activated while magnetic foreign matter generated in the reducing bath is removed using magnetic force. By removing magnetic foreign substances using magnetic force in this manner, it is possible to suppress contamination of the reduction bath, product substrates, and the like. In addition, in the example using the solution containing the surfactant, the micro-etching solution, and the solution containing the catalyst, similar to the example using the reducing agent solution, in the step (A-ii), Magnetic foreign matter is removed using magnetic force. By removing magnetic foreign matter using magnetic force in this manner, it is possible to suppress contamination of each liquid bath, product substrate, etc. Furthermore, even after going through steps (A-i) to (A-ii), there is usually no peeling or blistering at the interface between the obtained conductor layer and magnetic layer, and the peel strength is also low (A-i). From step (A-ii), the performance is equivalent to or higher than when step (A-ii) is not performed. Furthermore, the obtained product substrate can usually have improved relative magnetic permeability and reduced loss coefficient within a frequency range of 10 to 200 MHz. The above-mentioned mechanism can be applied to methods other than manufacturing a product substrate including the steps exemplified above.

Hereinafter, a first embodiment and a second embodiment of a method for manufacturing a product substrate will be described. However, the method for manufacturing a product substrate according to the present invention is not limited to the first and second embodiments illustrated below.

<First embodiment>
In the method for manufacturing a product substrate according to the first embodiment, before performing steps (A-i) to (A-ii),
(1) It is preferable to include the step of preparing a substrate having a magnetic layer (hereinafter, sometimes referred to as a "raw material substrate").

-(1) Process-
In the first embodiment of the method for manufacturing a product substrate, (1) the step of preparing a raw material substrate having a magnetic layer includes:
(1-1) It is preferable to include a step of filling the holes in the substrate with a resin composition, curing the resin composition, and forming a magnetic layer.

((1-1) process)
(1-1) In carrying out the step, a step of preparing a resin composition may be included. The resin composition is as described above. In the first embodiment, it is preferable to form the magnetic layer using magnetic paste.

Further, in performing the step (1-1), the manufacturing method according to the present embodiment includes a support substrate 11 and copper foil etc. provided on both surfaces of the support substrate 11, as shown in an example in FIG. The method may include a step of preparing a core substrate 10 including a first metal layer 12 and a second metal layer 13 made of metal. Examples of materials for the support substrate 11 include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. Examples of the materials for the first and second metal layers include copper foil with a carrier, materials for the conductor layer described below, and the like.

Furthermore, as an example shown in FIG. 2, the present manufacturing method may include a step of forming a through hole 14 as a hole in the core substrate 10. The through hole 14 can 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 hole may be a via hole instead of a through hole.

The through hole 14 can be formed using a commercially available drill device. Commercially available drill devices include, for example, "ND-1S211" manufactured by Hitachi Via Mechanics.

In this manufacturing method, after forming the through hole 14 in the core substrate 10, as shown in an example in FIG. and forming a plating layer 20 on the surface of the second metal layer 13.

As the roughening treatment, either dry or wet roughening treatment may be performed. Examples of dry roughening treatment include plasma treatment and the like. Furthermore, an example of the wet roughening treatment includes a method in which a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid are performed in this order.

The plating layer 20 is formed by a plating method, and the procedure for forming the plating layer 20 by the plating method is the same as that for forming a conductor layer in step (B) described later.

After preparing the core substrate 10 in which the plating layer 20 is formed in the through hole 14, the resin composition 30a is filled into the through hole 14, as shown in an example in FIG. As the filling method, for example, a method of filling the resin composition 30a into the through hole 14 via a squeegee, a method of filling the resin composition 30a via a cartridge, a method of filling the resin composition 30a by mask printing, Examples include a roll coating method and an inkjet method. Preferably, the resin composition 30a is a magnetic paste.

After filling the resin composition 30a into the through hole 14, the resin composition 30a is thermally cured to form the magnetic layer 30 inside the through hole 14, as shown in an example in FIG. The thermosetting conditions for the resin composition 30a vary depending on the composition and type of the resin composition 30a, but the curing temperature is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, and preferably The temperature is 240°C or lower, more preferably 220°C or lower, even more preferably 200°C or lower. The curing time of the resin composition 30a is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, and preferably 120 minutes or less, more preferably 100 minutes or less, and still more preferably 90 minutes or less. It is.

The degree of hardening of the magnetic layer 30 in step (1-1) is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The degree of curing can be measured using, for example, a differential scanning calorimeter.

Before thermally curing the resin composition 30a, the resin composition 30a may be subjected to a preliminary heat treatment in which the resin composition 30a is heated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition 30a, the resin composition 30a is cured at a temperature of usually 50°C or higher and lower than 120°C (preferably 60°C or higher and 110°C or lower, more preferably 70°C or higher and 100°C or lower). may be preheated for usually 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

((a) Process)
The step (a) is a step of polishing the surface of the magnetic layer, and the details of the step (a) are as follows: As an example is shown in FIG. 6, the surplus magnetic layer 30 protruding from or attached to the core substrate 10 is polished. In addition to removing and flattening the surface, a roughening process is performed to make the polished surface a roughened surface. As the polishing method, a method that can polish the excess magnetic layer 30 protruding from or attached to the core substrate 10 can be used. Examples of such polishing methods include buffing, belt polishing, and the like. Examples of commercially available buffing devices include "NT-700IM" manufactured by Ishii Yoki Co., Ltd.

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

After the step (a) and before the step (A-i), a heat treatment step may be performed if necessary for the purpose of further increasing the degree of hardening of the magnetic layer. The temperature in the heat treatment step may be carried out according to the curing temperature described above, and is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, and preferably 240°C or lower, more preferably 220°C or lower. , more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, and preferably 90 minutes or less, more preferably 70 minutes or less, and still more preferably 60 minutes or less.

-(A-i) process to (A-ii) process-
(1) After performing step (B) If wet plating is performed in step (B), before performing step (B) (A-i) Step of immersing the magnetic layer in an appropriate liquid stored in a liquid bath. I do. At this time, magnetic foreign matter may be generated in the immersion liquid. Examples of the embodiments of step (Ai) include the following embodiments A to D.

Embodiment A: (A-i) In the step, a raw substrate is immersed in a surfactant solution as an immersion liquid stored in a surfactant solution bath as a liquid bath. This immersion adjusts the surface charge on the magnetic layer to facilitate adsorption of the catalyst. At this time, the magnetic powder on the surface of the magnetic layer immersed in the surfactant solution may be eluted into the surfactant solution, and magnetic foreign matter may be generated in the bath.

Embodiment B: (A-i) In the step, the product substrate is immersed in a micro-etching liquid as an immersion liquid stored in a micro-etching liquid bath as a liquid bath. By bringing the micro-etching solution into contact with the product substrate, it is possible to remove the surfactant from areas where the surfactant is not needed, and to suppress adsorption of the catalyst to the areas where the surfactant is not needed. At this time, the magnetic powder on the surface of the magnetic layer immersed in the micro-etching solution may be eluted into the micro-etching solution, and magnetic foreign matter may be generated in the bath.

Embodiment C: (A-i) In the step, the product substrate is immersed in a solution containing a catalyst as an immersion liquid stored in a liquid bath containing a catalyst. By bringing a catalyst-containing solution into contact with the product substrate, the catalyst can be adsorbed onto the surface of the magnetic layer. At this time, the magnetic powder on the surface of the magnetic layer immersed in the catalyst-containing solution may be eluted into the catalyst-containing solution, and magnetic foreign matter may be generated in the bath.

Embodiment D: In the step (A-i), the magnetic layer is immersed in a reducing agent solution as an immersion liquid stored in a reducing bath as a liquid bath. This soaking may activate the catalyst. Normally, by immersing a magnetic layer coated with a catalyst in a reducing agent solution to generate catalyst nuclei, the catalyst coated on the surface of the magnetic layer is activated and the adhesion between the magnetic layer and the conductor layer is improved. can be improved. At this time, the magnetic powder on the surface of the magnetic layer immersed in the reducing agent solution is eluted into the reducing agent solution, and is then reduced and precipitated by the action of the reducing agent, resulting in magnetic foreign matter in the reducing bath. .

Therefore, in the present embodiments A to D, each magnetic foreign substance in a liquid bath such as (A-ii) a surfactant solution bath, a micro-etching liquid bath, a catalyst-containing liquid bath, and a reducing bath is removed by magnetic force. Remove using. Normally, a magnet is used as a source of magnetic force, and the magnetic force of the magnet attracts or fixes magnetic foreign matter, and the magnetic foreign matter is removed from a surfactant solution, micro-etching solution, catalyst-containing solution, or reducing agent solution. Remove foreign objects. The removed magnetic foreign matter can be recovered or discarded during or after the step (A-ii). This makes it possible to suppress contamination of the liquid bath and product substrate.

Magnetic foreign matter can be generated from the magnetic layer that is the object to be plated. Usually, the magnetic foreign matter originates from magnetic powder that is present on the surface of the magnetic layer and can come into contact with the liquid in the liquid bath. Such magnetic foreign matter may be a precipitate or precipitate that can be adsorbed or fixed by magnetic force. Preferably, the magnetic foreign matter does not contain components derived from the plating solution or the electrode material. Since the magnetic foreign matter is derived from magnetic powder, it is more preferable that it contains at least one selected from Fe, Co, Ni, and Mn, and more preferably it contains at least one of Fe and Mn. It is further preferable that Fe is included.

The source of the magnetic force may be inside the liquid bath, outside the liquid bath, or both inside and outside the liquid bath. The source of the magnetic force is preferably located outside the liquid bath, from the viewpoint of significantly obtaining the effects of the present invention. When the source of the magnetic force is inside the liquid bath, the magnet may be provided on the inner bottom surface of the liquid bath, or may be provided on the inner wall surface inside the liquid bath, or near the center inside the liquid bath. may be provided. When the source of the magnetic force is outside the liquid bath, the magnet may be provided at the outer bottom of the liquid bath, or may be provided on the outer wall surface of the liquid bath.

As the magnet that is the source of the magnetic force, one that can efficiently collect and remove magnetic foreign matter can be used, and either a permanent magnet or an electromagnet can be used. The magnet is preferably a permanent magnet from the viewpoint of significantly obtaining the effects of the present invention.

Examples of permanent magnets include alnico magnets; KS steel; MK steel; ferrite magnets; ferromagnetic iron nitride; platinum magnets; samarium cobalt magnets, neodymium (neodymium) magnets, praseodymium magnets, samarium nitrogen iron magnets, cerium-cobalt magnets, etc. Among these, rare earth magnets are preferred from the viewpoint of significantly obtaining the effects of the present invention, and among rare earth magnets, neodymium magnets are preferred.

As the electromagnet, either an alternating current type or a direct current type can be used. Examples of the electromagnet include air core electromagnets, iron core electromagnets, superconducting electromagnets, and the like.

The magnetic force of the magnet is preferably 0.1 T or more, more preferably 0.15 T or more, even more preferably 0.2 T or more, and preferably 10 T or less, more preferably is 7T or less, more preferably 5T or less.

A commercially available magnet may be used. Commercially available magnets include, for example, "N50" (neodymium magnet) manufactured by WTR, "EMT-1304NM" (neodymium magnet) manufactured by Fujiwara Sangyo Co., Ltd., "SF20" (Samakoba magnet) manufactured by Sagami Magnet Co., Ltd. Examples include ``GPM-8'' (neozypram magnet) and ``Alnico 5'' (alnico magnet). One type of magnet may be used alone, or two or more types may be used in combination.

The magnetic foreign matter collected by the magnet is removed, for example, by removing the magnet from the reducing bath.

It is preferable that steps (A-i) to (A-ii) are performed in this order in Embodiments A to D.

(Embodiment A)
In Embodiment A, a raw substrate is immersed in a surfactant solution as an immersion liquid stored in a surfactant solution bath as a liquid bath.

The solution containing a surfactant used in Embodiment A is a solution containing a surfactant that can clean the surface of the magnetic layer and adjust the surface charge so as to facilitate adsorption of the catalyst in Embodiment C. Can be used. Examples of such a solution include an alkaline solution containing a surfactant, an acid solution containing a surfactant, and the like, but an alkaline solution containing a surfactant is preferable from the viewpoint of suppressing magnetic foreign substances and the like.

The pH of the alkaline solution containing a surfactant is preferably higher than 7, more preferably 8 or higher, and still more preferably 10 or higher. The upper limit is not particularly limited, but may preferably be 14 or less, 13 or less, etc. The pH of the acid solution containing a surfactant is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. The upper limit is not particularly limited, but may preferably be less than 7, 6 or less, etc.

Examples of surfactants include cationic surfactants such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts; fatty acid salts such as sodium oleate, alkylsulfate salts, alkylbenzene sulfonates, and alkylsulfosuccinates. Anionic surfactants such as acid salts, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkanesulfonate sodium salts, alkyldiphenyl ether sulfonic acid sodium salts; polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene Examples include nonionic surfactants such as styryl phenyl ether, polyoxyethylene octiphenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene/polyoxypropylene copolymer.

As the surfactant, commercially available products can be used. Commercially available products include, for example, "Seculigand 902" manufactured by Atotech Japan Co., Ltd. and "PED-104" manufactured by Uemura Kogyo Co., Ltd.

From the viewpoint of facilitating adsorption of the catalyst, the treatment time in Embodiment A is preferably 1 minute or more, more preferably 2 minutes or more, even more preferably 3 minutes or more, and preferably 20 minutes or less, more preferably It is 15 minutes or less, more preferably 10 minutes or less.

The temperature of the solution containing the surfactant is preferably 30°C or higher, more preferably 40°C or higher, even more preferably 50°C or higher, and preferably 90°C or lower, from the viewpoint of facilitating catalyst adsorption. The temperature is preferably 80°C or lower, more preferably 70°C or lower.

(Embodiment B)
After carrying out Embodiment A as necessary, a step of immersing the product substrate in a micro-etching liquid as an immersion liquid stored in a micro-etching liquid bath as a liquid bath can be performed.

Examples of the micro-etching liquid used in Embodiment B include hydrochloric acid, sulfuric acid, hydrogen peroxide, sodium persulfate, ammonium persulfate, and liquids containing combinations thereof.

The concentration of the micro-etching solution is usually 2N or less, preferably 1.5N or less, more preferably 1N or less in terms of normality, from the viewpoint of removing the surfactant only from unnecessary parts, and the concentration of the surfactant is From the viewpoint of facilitating removal, it is preferably 0.1N or more, more preferably 0.2N or more, and even more preferably 0.5N or more.

The temperature of the micro-etching solution is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, and preferably 50°C or lower, more preferably from the viewpoint of facilitating the removal of the surfactant. is 40°C or lower, more preferably 30°C or lower.

The treatment time in Embodiment B is preferably 10 seconds or more, more preferably 15 seconds or more, even more preferably 30 seconds or more, and preferably 60 seconds or less, from the viewpoint of facilitating the removal of the surfactant. Preferably it is 50 seconds or less, more preferably 40 seconds or less.

(Embodiment C)
After carrying out Embodiments A and B as needed and before carrying out Embodiment D, a catalyst is usually added to the surface of the magnetic layer from the viewpoint of improving the adhesion between the magnetic layer and the conductor layer. An application step may be performed. The details of applying the catalyst are as follows: the magnetic layer is immersed in a solution containing the catalyst, and the catalyst is adsorbed onto the surface of the magnetic layer.

Examples of the catalyst include palladium salts, palladium complex compounds, tin-palladium complex salts, tin-palladium colloids, and the like.

The solution containing the catalyst is usually an alkaline solution. Thereby, the generation of magnetic foreign matter and the like can be significantly suppressed. The pH of this alkaline solution is preferably higher than 7, more preferably 8 or higher, still more preferably 10 or higher. The upper limit is not particularly limited, but may preferably be 14 or less, 13 or less, etc.

In addition, the concentration of the solution containing the catalyst is preferably 1 mmol/L or more, more preferably 5 mmol/L or more, and even more preferably 10 mmol/L or more in terms of normality from the viewpoint of adsorbing the catalyst to the entire magnetic layer. It is preferably 500 mmol/L or less, more preferably 300 mmol/L or less, even more preferably 100 mmol/L or less.

A commercially available solution can be used as the solution containing the catalyst. Commercially available products include, for example, "Activator Neogand 834" manufactured by Atotech Japan Co., Ltd. and "Brown Schumer" manufactured by Nippon Kanigen Co., Ltd.

The treatment time of the catalyst application step is preferably 1 minute or more, more preferably 2 minutes or more, even more preferably 3 minutes or more, and preferably 20 minutes or less, more preferably 2 minutes or more, from the viewpoint of adsorbing the catalyst to the entire magnetic layer. is 15 minutes or less, more preferably 10 minutes or less.

The temperature of the solution containing the catalyst is preferably 10°C or higher, more preferably 20°C or higher, even more preferably 30°C or higher, and preferably 60°C or lower, from the viewpoint of adsorbing the catalyst to the entire magnetic layer. The temperature is preferably 50°C or lower, more preferably 40°C or lower.

(Embodiment D)
After the catalyst application step is completed, as Embodiment D, a catalyst activation step may be performed to activate the catalyst applied to the surface of the magnetic layer. To activate the catalyst, the magnetic layer coated with the catalyst is usually immersed in a reducing agent solution to generate catalyst nuclei, thereby activating the catalyst coated on the surface of the magnetic layer.

Examples of the reducing agent used in Embodiment D include hypophosphite, a mixed solution of dimethylamine borane, and a potassium salt of an organic acid, and the like.

As the reducing agent solution, an acidic solution is usually used. The pH of this acidic solution is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. The upper limit is not particularly limited, but may preferably be less than 7, 6 or less, etc.

In addition, the concentration of the reducing agent in the reducing agent solution is preferably 0.3 N or more, more preferably 0.4 N or more, and even more preferably 0.4 N or more in terms of normality, from the viewpoint of activating the catalyst applied to the surface of the magnetic layer. It is 0.5N or more, preferably 3N or less, more preferably 2N or less, and still more preferably 1N or less.

A commercially available product can be used as the reducing agent solution. Commercially available products include, for example, "Reducer Accelerator 810 mod." manufactured by Atotech Japan, "Reducer Neogant WA", and "K-PVD" manufactured by Nippon Kanigen.

From the viewpoint of activating the catalyst, the treatment time during which the magnetic layer is immersed in the reducing agent solution is preferably 1 minute or more, more preferably 2 minutes or more, even more preferably 3 minutes or more, and preferably 20 minutes or less. , more preferably 15 minutes or less, still more preferably 10 minutes or less.

From the viewpoint of activating the catalyst, the temperature of the reducing agent solution is preferably 10°C or higher, more preferably 20°C or higher, even more preferably 30°C or higher, and preferably 60°C or lower, more preferably 50°C or lower. , more preferably 40°C or lower.

After completing steps (A-i) to (A-ii), a water washing treatment may be performed as necessary.

Steps (A-i) to (A-ii) are preferably carried out in Embodiment D in which a large amount of magnetic foreign matter is generated, and more preferably carried out in all of Embodiments A to D.

-(B) Process-
In step (B), as an example shown in FIG. 7, a conductor layer 40 is formed by wet plating on the magnetic layer 30 after steps (Ai) to (A-ii) are completed. Furthermore, after forming the conductor layer 40, as shown in an example in FIG. A patterned conductor layer 41 may also be formed.

Materials for the conductor layer include, for example, single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium; gold, platinum, palladium, and silver. , copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Among them, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, nickel-chromium alloy, copper-nickel alloy, copper-titanium alloy can be used from the viewpoint of versatility, cost, ease of patterning, etc. Preferably, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy is used, and copper is even more preferably used.

In a preferred embodiment of the step (B), it is preferable to perform electroless plating treatment to form a conductor layer, and after performing electroless plating treatment, it is preferable to further perform electrolytic plating treatment to form a conductor layer. More preferred. Therefore, in step (B), it is preferable to form a plated conductor layer on the surface of the magnetic layer by a semi-additive method, a fully additive method, or the like. In step (B), the conductor layer is preferably formed by a semi-additive method from the viewpoint of ease of manufacturing the conductor layer.

The details of the semi-additive method are as follows: First, a plating seed layer is formed as part of the conductor layer on the surface of the magnetic layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer to expose a portion of the plating seed layer corresponding to a desired wiring pattern. After forming the remaining conductor layer on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary plating seed layers can be removed by etching or the like to form a conductor layer having a desired wiring pattern.

The electroless plating treatment is performed by immersing the magnetic layer in an electroless plating solution. Examples of the electroless plating treatment include electroless copper plating treatment, electroless nickel plating treatment, electroless nickel-tungsten plating treatment, electroless tin plating treatment, electroless gold plating treatment, etc. is preferred.

Examples of the electroless plating solution used in the electroless plating process include solutions containing metal ions such as copper, nickel, tungsten, tin, gold, palladium, and PdCl ₂ . Further, the electroless plating solution may contain other additives such as a reducing agent. A commercially available product can be used as the electroless plating solution. Commercially available products include, for example, "Surcap PEA" manufactured by Uemura Kogyo Co., Ltd. and "S-KPD" manufactured by Nippon Kanigen Co., Ltd.

From the viewpoint of activating the catalyst, the treatment time of the electroless plating treatment is preferably 10 minutes or more, more preferably 20 minutes or more, even more preferably 30 minutes or more, and preferably 60 minutes or less, more preferably 50 minutes or more. The time is preferably 40 minutes or less, more preferably 40 minutes or less.

The processing temperature of the electroless plating treatment is preferably 10°C or higher, more preferably 20°C or higher, even more preferably 30°C or higher, and preferably 60°C or lower, more preferably is 55°C or lower, more preferably 50°C or lower.

After forming a plating seed layer by electroless plating, a dry film is laminated on the plating seed layer. Thereafter, exposure and development are performed using a photomask under predetermined conditions so that a portion of the plating seed layer is exposed in accordance with a desired wiring pattern, thereby forming a mask pattern. Exposure and development conditions can be carried out under already known conditions.

As the dry film, a photosensitive dry film made of a photoresist composition can be used. Examples of such dry films include novolac resins, acrylic resins, and the like.

The mask pattern is used as a plating mask in electrolytic copper plating. After electroplating, the mask pattern is removed.

The electrolytic plating process is performed by immersing the magnetic layer after the electroless plating process in a plating bath. At this time, an electric current is passed through the plating bath. Examples of the electrolytic plating treatment include electrolytic copper plating, electrolytic nickel plating, electrolytic tin plating, electrolytic gold plating, etc., and electrolytic copper plating is preferable.

Examples of the plating bath used in electrolytic plating include baths containing copper sulfate, copper pyrophosphate, copper cyanide, and the like.

From the viewpoint of activating the catalyst, the electrolytic plating treatment time is preferably 30 minutes or more, more preferably 40 minutes or more, even more preferably 50 minutes or more, and preferably 90 minutes or less, more preferably 80 minutes. The duration is preferably 70 minutes or less.

From the viewpoint of improving the efficiency of conductor layer formation, the treatment temperature of the electrolytic plating treatment is preferably 10°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, and preferably 50°C or lower, more preferably The temperature is 40°C or lower, more preferably 30°C or lower.

The current density of the electrolytic plating treatment is preferably 1.0 A/dm ² or more, more preferably 1.5 A/dm ² or more, and even more preferably 2.0 A/dm ^{2 or more, from the viewpoint of improving the efficiency of conductor layer formation} . and is preferably 4.0 A/dm ² or less, more preferably 3.5 A/dm ² or less, even more preferably 3.0 A/dm ² or less.

After forming the conductor layer, an annealing treatment may be performed if necessary for the purpose of improving the peel strength of the conductor layer. The annealing treatment can be performed, for example, by heating the conductor layer at 150 to 200° C. for 20 to 90 minutes.

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, even more preferably 40 μm or less, particularly preferably 30 μm or less, and 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, even more preferably 5 μm or more.

<Second embodiment>
A second embodiment of the method for manufacturing a product substrate will be described below. Descriptions of parts that overlap with those of the first embodiment will be omitted as appropriate.

In the method for manufacturing a product substrate according to the second embodiment, before performing steps (A-i) to (A-ii),
(α) It is preferable to perform a step of preparing a raw material substrate having a magnetic layer.
In the second embodiment, it is preferable to form the magnetic layer using a magnetic sheet.

(α) In the second embodiment of the method for manufacturing a product substrate, the step of preparing a raw material substrate having a magnetic layer is as follows:
(α-1) A step of laminating the magnetic sheet on the inner layer substrate such that the resin composition layer is bonded to the inner layer substrate, and thermally curing the resin composition layer to form a magnetic layer, and (α-2) Magnetic Preferably, the method includes a step of drilling holes in the layer.

-(α-1) Process-
The step (α-1) may include a step of preparing a magnetic sheet. The magnetic sheet is as described above.

In the step (α-1), as an example shown in FIG. A magnetic sheet 310 is laminated on the inner layer substrate 200 so as to be bonded to the inner layer substrate 200 .

The inner layer substrate 200 is an insulating substrate. Examples of the material for the inner layer substrate 200 include insulating substrates 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 board 200 may be an inner layer circuit board in which wiring and the like are built into its thickness.

As an example is shown in FIG. 9, the inner layer substrate 200 has a first conductor layer 420 provided on the first main surface 200a and an external terminal 240 provided on the second main surface 200b. The first conductor layer 420 includes a plurality of wires. In the illustrated example, only the wiring constituting the coiled conductive structure 400 of the inductor element is shown. The external terminal 240 is a terminal for electrically connecting to an external device (not shown) or the like. External terminal 240 can be configured as part of a conductor layer provided on second main surface 200b.

The conductor materials that can constitute the first conductor layer 420, the external terminals 240, and other conductor layers are the same as the materials for the conductor layer described in the section "-(B) Step-" of the first embodiment.

The first conductor layer 420, external terminal 240, and other conductor layers may have a single layer structure or a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. Good too. Further, the thicknesses of the first conductor layer 420, external terminals 240, and other conductor layers are the same as those of the pattern conductor layer in the first embodiment.

The line (L)/space (S) ratio of the first conductor layer 420 and the external terminal 240 is not particularly limited, but is usually 900/900 μm or less from the viewpoint of reducing surface irregularities and obtaining a magnetic layer with excellent smoothness. , preferably 700/700 μm or less, more preferably 500/500 μm or less, further preferably 300/300 μm or less, even more preferably 200/200 μm or less. The lower limit of the line/space ratio is not particularly limited, but from the viewpoint of improving the embedding of the resin composition layer into the space, it is preferably 1/1 μm or more.

Inner layer substrate 200 has a plurality of through holes 220 that penetrate inner layer substrate 200 from first main surface 200a to second main surface 200b. The through hole 220 is provided with an in-through hole wiring 220a. The through-hole wiring 220a electrically connects the first conductor layer 420 and the external terminal 240.

The resin composition layer 320a and the inner layer substrate 200 can be bonded, for example, by heat-pressing the magnetic sheet 310 to the inner layer substrate 200 from the support 330 side. Examples of the member for hot-pressing the magnetic sheet 310 to the inner layer substrate 200 (hereinafter also referred to as "heat-pressing member") include a heated metal plate (stainless steel (SUS) mirror plate, etc.), a metal roll (SUS roll), etc. can be mentioned. Note that instead of pressing the thermocompression bonding member in direct contact with the magnetic sheet 310, a sheet made of an elastic material such as heat-resistant rubber or the like is used so that the magnetic sheet 310 sufficiently follows the unevenness of the surface of the inner layer substrate 200. It is preferable to press through the .

The temperature during thermocompression bonding is preferably in the range of 80°C to 160°C, more preferably 90°C to 140°C, still more preferably 100°C to 120°C, and the pressure during thermocompression bonding is preferably 0. The pressure is in the range of 098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, and the time for heat-pressing is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. It is preferable that the magnetic sheet and the inner layer substrate be bonded under reduced pressure conditions of 26.7 hPa or less.

The resin composition layer 320a of the magnetic sheet 310 and the inner substrate 200 can be bonded using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurized laminator manufactured by Meiki Seisakusho, and a vacuum applicator manufactured by Nikko Materials.

After the magnetic sheet 310 and the inner layer substrate 200 are bonded, the stacked magnetic sheets 31 may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression bonding member from the support side. . The pressing conditions for the smoothing treatment can be the same as the conditions for the heat-pressing of the lamination described above. The smoothing process can be performed using a commercially available laminator. Note that the lamination and smoothing treatment may be performed continuously using the above-mentioned commercially available vacuum laminator.

After laminating the magnetic sheet on the inner layer substrate, the resin composition layer is thermally cured to form a magnetic layer. As an example shown in FIG. 10, the first magnetic layer 320 is formed by thermosetting the resin composition layer 320a bonded to the inner layer substrate 200. The conditions for heat curing are the same as those described in the section "-(1-1) Step-" of the first embodiment.

The support 330 may be removed between the heat curing step (α-1) and the (α-2) step, or may be peeled off after the (α-2) step.

Further, step (α-1) may be performed by directly applying or printing a paste-like resin composition onto the inner layer substrate instead of laminating the magnetic sheet on the inner layer substrate.

-(α-2) Process-
In the step (α-2), as an example shown in FIG. 11, the first magnetic layer 320 is drilled to form a via hole 360. The via hole 360 becomes a path for electrically connecting the first conductor layer 420 and a second conductor layer 440, which will be described later. The via hole 360 can be formed by the same method as that for forming the through hole described in the section "-(1-1) Step-".

-(a) Process-
After the step (α-2), a step (a) of polishing the surface of the magnetic layer may be performed, and a roughening treatment may be performed to make the polished surface a roughened surface. The roughening method in step (a) can be performed by polishing similar to that described in the section "-(a) step-" of the first embodiment.

The arithmetic mean roughness (Ra) of the roughened surface of the magnetic layer after the step (a) is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably It is 400 nm or more. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, even more preferably 800 nm or less. Surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

-(A-i) process to (A-ii) process-
If wet plating is performed in step (α) or step (B) after step (a), the magnetic layer (A-i) is immersed in a liquid stored in a liquid bath before step (B) is performed. (A-ii) A step of removing magnetic foreign matter generated in the liquid using magnetic force. By performing steps (A-i) to (A-ii), it is possible to suppress contamination of liquid baths such as reduction baths and product substrates due to magnetic foreign substances. Furthermore, the adhesion between the magnetic layer and the conductor layer can be improved. Steps (A-i) to (A-ii) are as described in the first embodiment.

-(B) Process-
In step (B), as an example shown in FIG. 12, a second conductor layer 440 is formed on the first magnetic layer 320 after steps (Ai) to (A-ii) are completed. The method of forming the second conductor layer 440 is as described in the first embodiment. Note that via this step, an in-via hole wiring 360a is also formed in the via hole 360. The conductor layer 400 is formed by forming the second conductor layer 440. The second conductor layer 440 includes a plurality of wires.

The conductor material that can constitute the second conductor layer 440 is the same as that of the first conductor layer 420. The second conductor layer 440 may have a single layer structure or a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the second conductor layer 440 has a multilayer structure, the layer in contact with the magnetic layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy. Further, the thickness of the second conductor layer 440 is similar to the thickness of the first conductor layer 420.

The first conductor layer 420 and the second conductor layer 440 may be provided in a spiral shape, for example, as shown in FIGS. 13 to 15, which will be described later. In one example, one end of the spiral wiring portion of the second conductor layer 440 on the center side is electrically connected to one end of the spiral wiring portion of the first conductor layer 420 on the center side by the via hole wiring 360a. has been done. 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 420a of the first conductor layer 42 by a via hole wiring 360a. Therefore, the other end on the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the external terminal 240 via the via hole wiring 360a, the land 420a, and the through hole wiring 220a.

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

After the step (B), a step of forming a magnetic layer on the conductor layer may be performed. In detail, as an example is shown 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 via hole wiring 360a are formed. The second magnetic layer 340 can be formed by the same steps as those already described.

<Physical properties of product substrate, etc.>
Since the method for manufacturing a product substrate of the present invention includes the step (A-ii), it exhibits the characteristic that the amount of magnetic foreign matter in the electroless plating process can be suppressed. The amount of precipitated magnetic foreign matter is preferably less than 300 mg, more preferably 250 mg or less, even more preferably 200 mg or less, and even more preferably 150 mg or less. The lower limit is not particularly limited, but may be 0.001 mg or more. Measurement of magnetic foreign substances and the like can be performed according to the method described in the Examples described later.

In a product board manufactured through the (A-ii) process, the peel strength of the copper plating between the conductive layer and the magnetic layer, which are formed by copper plating, is usually the same as that of the product board manufactured without the (A-ii) process. The peel strength of the copper plating between the magnetic layer and the conductor layer of the product substrate is equivalent to or higher than that of the product board. That is, even if step (A-ii) is performed, the peel strength will not usually deteriorate. The copper plating peel strength is preferably 0.05 kgf/cm or more, more preferably 0.1 kgf/cm or more, and still more preferably 0.15 kgf/cm or more. The upper limit is not particularly limited, but may be 10 kgf/cm or less. The copper plating peel strength can be measured according to the method described in the Examples below.

The product board manufactured by the product board manufacturing method of the present invention is preferably a circuit board or an inductor board having an inductor element formed of a patterned conductor layer.

[Inductor board]
The inductor substrate includes a product substrate obtained by the method for manufacturing a product substrate of the present invention. When such an inductor board includes the product board obtained by the first embodiment of the product board manufacturing method, it has an inductor element formed of a conductor on at least a portion of the periphery of the magnetic layer. As such an inductor substrate, for example, the one described in Japanese Patent Application Publication No. 2016-197624 can be applied.

Further, when including the product substrate obtained by the second embodiment of the product substrate manufacturing method, the inductor substrate has a magnetic layer and a conductive structure at least partially embedded in the magnetic layer. , includes the conductive structure and an inductor element configured by a portion of the magnetic layer that extends in the thickness direction of the magnetic layer and is surrounded by the conductive structure. Here, FIG. 13 is a schematic plan view of an inductor substrate containing an inductor element viewed from one side in the thickness direction. FIG. 14 is a schematic view showing a cut end surface of the inductor substrate cut at the position indicated by the dashed line II-II shown in FIG. FIG. 15 is a schematic plan view for explaining the configuration of the first conductor layer of the inductor board.

As shown in FIGS. 13 and 14 as an example, the inductor substrate 100 includes a plurality of magnetic layers (a first magnetic layer 320, a second magnetic layer 340) and a plurality of conductor layers (a first conductor layer 420, a second conductor layer 440), that is, a build-up wiring board having a build-up magnetic layer and a build-up conductor layer. Further, the inductor substrate 100 includes an inner layer substrate 200.

From FIG. 14, the first magnetic layer 320 and the second magnetic layer 340 constitute a magnetic section 300 that can be seen as an integrated magnetic layer. Therefore, the coiled conductive structure 400 is provided so that at least a portion thereof is embedded in the magnetic part 300. That is, in the inductor substrate 100 of this embodiment, the inductor element includes the coiled conductive structure 400 and the magnetic section 300 that extends in the thickness direction of the magnetic section 300 and is surrounded by the coiled conductive structure 400. It is made up of a core that is a part of the core.

As shown in FIG. 15 as an example, the first conductor layer 420 includes a spiral wiring part for configuring the coiled conductive structure 400 and a rectangular wiring part electrically connected to the through-hole wiring 220a. and a land 420a. In the illustrated example, the spiral wiring portion includes a bent portion that is bent at right angles to the straight portion and a detour portion that detours around the land 420a. In the illustrated example, the spiral wiring portion of the first conductor layer 420 has a substantially rectangular overall outline, and has a shape that is wound counterclockwise from the center toward the outside.

Similarly, a second conductor layer 440 is provided on the first magnetic layer 320. The second conductor layer 440 includes a spiral wiring portion for forming the coiled conductive structure 400 . In FIG. 13 or 14, the spiral wiring portion includes a straight portion and a bent portion bent at right angles. In FIG. 13 or 14, the spiral wiring portion of the second conductor layer 44 has a substantially rectangular overall outline, and has a shape that is wound clockwise from the center toward the outside.

Such an inductor board 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 such a wiring board as an inner layer board. Moreover, such a wiring board can be used as a chip inductor component made into individual pieces, and the chip inductor component can also be used as a surface-mounted printed wiring board.

Furthermore, various types of semiconductor devices can be manufactured using such a wiring board. Semiconductor devices including such wiring boards can be suitably used in electrical products (e.g., computers, mobile phones, digital cameras, televisions, etc.) and vehicles (e.g., motorcycles, automobiles, trains, ships, aircraft, etc.). .

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass," respectively, unless otherwise specified.

<Example 1>
15 parts by mass of epoxy resin ("ZX-1059", a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.), epoxy resin ("ZX-1658", cycloaliphatic diglydyl ether) 5 parts by mass of dispersant ("RS-710", polymeric anionic dispersant, manufactured by Toho Chemical Co., Ltd.), curing accelerator ("2MZA-PW", imidazole) 1 part by mass of hardening accelerator (manufactured by Shikoku Kasei Co., Ltd.) and 150 parts by mass of magnetic powder ("M05S", Fe-Mn ferrite, average particle size 3 μm, manufactured by Powder Tech Co., Ltd.) were mixed to form a paste-like resin composition. I prepared something.

<Preparation of evaluation board>
As a printing board, both sides of a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, board thickness 0.8 mm, board size 3 cm x 10 cm, Matsushita Electric Works R1515A) were coated with a micro-etching agent (MEC Co., Ltd.). The copper surface was roughened by etching it by 1 μm using CZ8100 (manufactured by CZ8100). On the prepared printing board, the resin composition of Example 1 prepared in advance was uniformly applied using a doctor blade to form a paste layer with a thickness of approximately 120 μm. The paste layer was heated at 130° C. for 30 minutes and further heated at 145° C. for 30 minutes to thermally cure it, thereby forming a magnetic layer. After buffing the surface of the formed magnetic layer, it was washed with high-pressure water (0.1 MPa, 15 seconds) and heat-treated by heating at 180° C. for 30 minutes. The produced substrates were cut into 5 cm square pieces, and these substrates were used as evaluation boards.

<Evaluation of magnetic foreign matter in electroless plating process>
The evaluation board was immersed in a reducing bath containing a reducing agent solution ("Reducer Accelerator 810 mod.", manufactured by Atotech Japan Co., Ltd., 60 ml; "Reducer Neogant WA", manufactured by Atotech Japan Co., Ltd., 3 ml) at 40 ° C. for 24 hours. . At this time, one neodymium magnet ("N50" manufactured by WTR, 0.85T, diameter 10 mm, thickness 2 mm, round shape) was attached to the outer wall of the reducing solution bath. In the Examples and Comparative Examples, among the precipitates (magnetic foreign substances) precipitated in the bath, those collected by the magnet were removed using filter paper (manufactured by Kiriyama Seisakusho Co., Ltd., No. 5B, 60φ) to remove magnetic particles as insoluble substances. Foreign matter was filtered out. In Reference Example 1, the precipitate (insoluble matter) precipitated in the liquid was collected, and the insoluble matter was filtered out using a filter paper (manufactured by Kiriyama Seisakusho Co., Ltd., No. 5B, 60φ). After vacuum-drying the filtered magnetic foreign matter (insoluble matter in Reference Example 1) for 5 hours, the amount of magnetic foreign matter (insoluble matter in Reference Example 1) was measured using a precision balance, and evaluated based on the following criteria.
○: The amount of magnetic foreign matter (insoluble matter in Reference Example 1) is less than 300 mg ×: The amount of magnetic foreign matter (insoluble matter in Reference Example 1) is 300 mg or more

<Evaluation of copper plating peel strength>
The evaluation board was immersed in a mixture of a solution containing PdCl ₂ (“Activator Neogant 834” manufactured by Atotech Japan Co., Ltd.) and sodium hydroxide at 40°C for 5 minutes, and then immersed in a reducing solution (“Reducer Neogant 834” made by Atotech Japan Co., Ltd.) at 40°C. Gantt WA" and "Reducer Accelerator 810 mod." mixture solution) at 30° C. for 5 minutes. At this time, one neodymium magnet ("N50" manufactured by WTR, diameter 10 mm, thickness 2 mm, round shape) was attached to the outer wall of the reduction bath. It was immersed in a mixed solution of an electroless copper plating solution ("Surcap PEA" manufactured by Uemura Kogyo Co., Ltd.) and formaldehyde at 35° C. for 30 minutes. After annealing by heating at 150°C for 30 minutes, it was heated to 22°C in a copper sulfate electrolytic plating solution (mixture of Atotech Japan's "Additive Cupracid HL", copper sulfate pentahydrate, and sulfuric acid). It was immersed for 60 minutes to form a conductor layer with a thickness of 30 μm on the magnetic layer. Next, annealing treatment was performed at 180° C. for 60 minutes. This substrate was used as a peel strength evaluation substrate.

A cut with a width of 10 mm and a length of 100 mm is made in the conductor layer of this peel strength evaluation board, and one end is peeled off using a gripping tool (manufactured by TSE, Autocom type tester "AC-50C-SL"). '') and peeled off 35 mm in the vertical direction at a speed of 50 mm/min at room temperature, and the load (kgf/cm) was measured.

<Example 2>
In Example 1, 150 parts by mass of magnetic powder ("M05S", Fe-Mn ferrite, average particle size 3 μm, manufactured by Powder Tech) was replaced with magnetic powder ("AW2-08PF3F", Fe-Cr-Si ferrite). 210 parts by mass of alloy (amorphous), average particle size 3 μm, manufactured by Epson Atomics Co., Ltd.). A resin composition and an evaluation board were prepared in the same manner as in Example 1 except for the above matters, and magnetic foreign substances and copper plating peel strength were evaluated.

<Comparative example 1>
In Example 1, magnetic foreign matter and copper plating peel strength were evaluated without using a magnet. A resin composition and an evaluation board were prepared in the same manner as in Example 1 except for the above matters, and magnetic foreign substances and copper plating peel strength were evaluated.

<Comparative example 2>
In Example 2, magnetic foreign matter and copper plating peel strength were evaluated without using a magnet. A resin composition and an evaluation board were prepared in the same manner as in Example 2 except for the above matters, and magnetic foreign substances and copper plating peel strength were evaluated.

<Reference example 1>
In Example 1, 150 parts by mass of magnetic powder ("M05S", Fe-Mn ferrite, average particle size 3 μm, manufactured by Powder Tech) was replaced with 60 parts by mass of silica ("SC2050", manufactured by Admatex). , magnetic foreign matter and copper plating peel strength were evaluated without using a magnet. A resin composition and an evaluation board were prepared in the same manner as in Example 1 except for the above matters, and the insoluble matter and copper plating peel strength were evaluated.

From Examples 1 and 2, it was found that by removing magnetic foreign substances in the reducing bath using a magnet, the amount of magnetic foreign substances floating in the reducing agent solution could be greatly suppressed. On the other hand, in Comparative Examples 1 and 2 in which the step (A-ii) was not performed, a large amount of magnetic foreign matter was precipitated. Furthermore, compared to the amount of insoluble matter in Reference Example 1, the results of Examples 1 and 2 do not deviate significantly, which indicates that the amount of magnetic foreign matter derived from magnetic powder floating in the liquid was greatly suppressed. Understood.
Furthermore, even if step (A-ii) was performed, there was no significant difference in the copper plating peel strength results, and it was also confirmed that no deterioration in physical properties occurred.

<Manufacture of circuit boards>
As the inner layer substrate, a glass cloth-based epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, substrate size 3 cm×10 cm, R1515A manufactured by Matsushita Electric Works Co., Ltd.) was prepared.

The paste-like resin composition prepared in Example 1 was printed on the inner layer substrate to form a paste layer. After forming the paste layer, it was heated at 130°C for 30 minutes, and further heated at 145°C for 30 minutes. Thereafter, the surface of the paste layer was buffed. The paste layer was further heat-cured by heating at 180° C. for 30 minutes to obtain a magnetic layer.

The magnetic layer was washed with high-pressure water (0.1 MPa, 15 seconds) and heat-treated by heating at 180° C. for 30 minutes.

Next, the magnetic layer was immersed in Cleaner Securigand 902 manufactured by Atotech Japan Co., Ltd. at 60° C. for 5 minutes, washed with water, and then treated with a micro-etching solution (Na ₂ S ₂ O ₈ : 100 g/L, H ₂ SO ₄ ( After being immersed in 75% aq.) (14.2 ml/L) at 30° C. for 1 minute, a water washing treatment was performed.

Next, as a catalyst application step, the magnetic layer was immersed in PdCl ₂ -containing activator Neogand 834 (manufactured by Atotech Japan Co., Ltd.) at 35° C. for 5 minutes, and then washed with water.

As a catalyst activation step, the magnetic layer was immersed in a reducing agent solution manufactured by Atotech Japan (Reducer Neogand WA: 5 ml/L, Reducer Accelerator 810 mod: 100 ml/L) at 30° C. for 5 minutes. At this time, one neodymium magnet ("N50" manufactured by WTR, diameter 10 mm, thickness 2 mm, round shape) was attached to the outer wall of the reduction bath.

As the process of forming the conductor layer, it was immersed in a mixture of a solution containing PdCl ₂ (Atotech Japan's "Activator Neogant 834") and sodium hydroxide at 40°C for 5 minutes, and then immersed in an electroless copper plating solution. It was immersed for 20 minutes at 25°C. After annealing by heating at 150°C for 30 minutes, it was heated to 22°C in a copper sulfate electrolytic plating solution (mixture of Atotech Japan's "Additive Cupracid HL", copper sulfate pentahydrate, and sulfuric acid). It was immersed for 60 minutes to form a conductor layer with a thickness of 30 μm on the magnetic layer. Next, annealing treatment was performed at 180° C. for 30 minutes and then further at 180° C. for 60 minutes. Next, an etching resist was formed and a pattern was formed by etching to obtain a circuit board.

In this circuit board, there was no peeling or swelling at the interface between the surface of the magnetic layer and the conductor layer, and the plating adhesion was good.

10 core substrate 11 support substrate 12 first metal layer 13 second metal layer 14 through hole 20 plating layer 30a resin composition 30 magnetic layer 40 conductor layer 41 pattern conductor layer 100 inductor substrate 200 inner layer substrate 200a first main surface 200b second Main surface 220 Through hole 220a Wiring in through hole 240 External terminal 300 Magnetic section 310 Magnetic sheet 320a Resin composition layer 320 First magnetic layer 330 Support 340 Second magnetic layer 360 Via hole 360a Wiring in via hole 400 Coiled conductive structure 420 First conductor layer 420a Land 440 Second conductor layer

Claims (20)

A method for manufacturing a substrate in which a conductive layer is formed by wet plating on a magnetic layer containing magnetic powder, the method comprising:
(A-i) A step of immersing the magnetic layer in a liquid stored in a liquid bath, and (A-ii) Using magnetic force to remove magnetic foreign matter generated in the liquid to contaminate the liquid bath and substrate. At the same time, the process of suppressing
After the steps (A-i) and (A-ii), (B) forming a conductor layer on the magnetic layer by wet plating ,
A method for manufacturing a substrate , wherein the liquid contained in the liquid bath is any one of a surfactant solution, a microetching liquid, a catalyst-containing solution, and a reducing agent solution . The method for manufacturing a substrate according to claim 1, wherein in the step (A-ii), the magnetic foreign matter is generated from the magnetic layer. 3. The method for manufacturing a substrate according to claim 1, wherein the magnetic foreign material contains at least one selected from Fe, Co, Ni, and Mn. The method for manufacturing a substrate according to any one of claims 1 to 3, wherein the magnetic foreign material contains at least one selected from Fe and Mn. The method for manufacturing a substrate according to any one of claims 1 to 4, wherein the magnetic foreign material contains Fe. The method for manufacturing a substrate according to any one of claims 1 to 5, wherein the source of magnetic force is located inside a liquid bath. The method for manufacturing a substrate according to any one of claims 1 to 6, wherein the source of the magnetic force is outside the liquid bath. The method for manufacturing a substrate according to any one of claims 1 to 7, wherein in step (B), a conductor layer is formed by electroless plating. The method for manufacturing a substrate according to any one of claims 1 to 8, wherein in the step (B), electroless copper plating is performed to form a conductor layer. The method for manufacturing a substrate according to any one of claims 1 to 9, wherein in step (B), after performing electroless plating treatment, further electrolytic plating treatment is performed to form a conductor layer. Before step (A-i) and step (A-ii),
The method for manufacturing a substrate according to claim 1, further comprising: (a) polishing the surface of the magnetic layer. 12. The method for manufacturing a substrate according to claim 1, wherein the substrate is an inductor substrate having an inductor element formed of a patterned conductor layer. 13. The method for manufacturing a substrate according to claim 1, wherein the magnetic layer is formed by curing a resin composition containing magnetic powder and a binder resin. The method for manufacturing a substrate according to claim 13, wherein the binder resin includes a thermosetting resin. The method for manufacturing a substrate according to claim 14, wherein the thermosetting resin is an epoxy resin. Manufacturing the substrate according to any one of claims 13 to 15, wherein the content of the magnetic powder is 70% by mass or more and 98% by mass or less when the nonvolatile components in the resin composition are 100% by mass. Method. The method for manufacturing a substrate according to any one of claims 13 to 16, wherein the resin composition is a paste-like resin composition. The method for manufacturing a substrate according to any one of claims 1 to 17, wherein the magnetic powder is at least one selected from iron oxide powder and iron alloy metal powder. The substrate according to any one of claims 1 to 18, wherein the magnetic powder contains iron oxide powder, and the iron oxide powder contains ferrite containing at least one selected from Ni, Cu, Mn, and Zn. manufacturing method. The method for manufacturing a substrate according to any one of claims 1 to 19, wherein the magnetic powder contains iron alloy metal powder containing at least one selected from Si, Cr, Al, Ni, and Co.

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