JP7222228B2 - Substrate manufacturing method - Google Patents

Description

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

Inductors called power inductors, high-frequency inductors, and common mode choke coils are widely used in information terminals such as mobile phones and smartphones. Conventionally, an independent inductor component was mounted on a circuit board, but in recent years, a method of forming a coil with a conductor pattern of the circuit board and providing the inductor inside the circuit board has been adopted.

For example, in Patent Document 1, a spiral conductor pattern with multiple turns is formed on multiple layers of a multilayer substrate, and the ends of the conductor pattern of each layer are connected to upper and lower layers to form a spiral coil as a whole. , a multi-layer circuit board with an embedded inductor is disclosed. Further, Patent Document 2 discloses that an inductor substrate is embedded in a core substrate of a circuit board in order to reduce the thickness of the circuit board.

When manufacturing an inductor substrate in which an inductor is formed by a plurality of conductor patterns formed on an insulating layer, it is conceivable 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 be prevented. For example, Patent Literature 2 discloses that a magnetic powder is contained in a resin composition forming a resin composition layer of a resin sheet with a support, 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. Disclosed is an inductor substrate that achieves a small size and high inductance by arranging the magnetic core at the center of the coil.

JP 2009-16504 A JP 2012-186440 A JP 2016-197624 A

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

However, as a result of extensive studies on the formation of a conductor layer on a magnetic layer by wet plating, the present inventors found that during the wet plating process, precipitates and It has been found that deposits are formed and contaminate the bath, substrate and the like. In particular, when performing electroless plating, it was found that the contamination becomes conspicuous in the catalyst activation step of applying a catalyst such as palladium to the surface of the magnetic layer and then activating the catalyst with a reducing agent.

The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a substrate manufacturing method capable of suppressing the generation of .

In order to achieve the above object, the present inventors have made intensive studies and found that deposits and precipitates derived from magnetic powder during wet plating can be removed by treating the surface of the magnetic layer with an acid solution before wet plating. We have found that it can be suppressed, and have 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, comprising:
A method of manufacturing a substrate, comprising: (A) an acid treatment step of treating the surface of a magnetic layer with an acid solution; and (B) a step of forming a conductor layer on the magnetic layer whose surface has been treated with the acid solution.
[2] The method according to [1], wherein the step (B) performs electroless plating to form a conductor layer.
[3] The method according to [1] or [2], wherein the concentration of the acid solution in step (A) is 3N or more.
[4] The method according to any one of [1] to [3], wherein the concentration of the acid solution in step (A) is 3N or more and 40N or less.
[5] The method according to any one of [1] to [4], wherein the acid solution in step (A) contains an inorganic acid.
[6] The method according to any one of [1] to [5], wherein the acid solution in step (A) is at least one selected from hydrochloric acid, sulfuric acid and nitric acid.
[7] The method according to any one of [1] to [6], wherein the acid solution in step (A) is hydrochloric acid.
[8] (A) After the step (B) Before the step,
(3) The method according to any one of [1] to [7], further comprising a conditioning step of treating the surface of the magnetic layer with a solution containing a surfactant.
[9] (3) After the step (B) Before the step,
The method according to [8], further comprising (4) a catalyzing step of applying a catalyst to the surface of the magnetic layer, and (5) a catalyst activating step of activating the catalyst, in this order.
[10] The method according to any one of [1] to [9], wherein in step (B), electroless plating is performed and then electroplating is performed to form a conductor layer.
[11] (A) Before the step,
(1) The method according to any one of [1] to [10], further comprising the step of filling the through-holes with a pasty resin composition and curing the resin composition to form a magnetic layer.
[12] (1) After the step (A) Before the step,
(2) The method of [11], further comprising the step of polishing the surface of the magnetic layer.
[13] The method according to any one of [1] to [12], wherein the substrate is an inductor substrate having inductor elements formed by patterned conductor layers.
[14] The method 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 of [14], wherein the binder resin comprises a thermosetting resin.
[16] The method of [15], wherein the thermosetting resin is an epoxy resin.
[17] The magnetic powder according to any one of [11] to [16], wherein the content of the magnetic powder is 70% by mass or more and 98% by mass or less when the non-volatile component in the resin composition is 100% by mass. Method.
[18] The method according to any one of [1] to [17], wherein the magnetic powder is at least one selected from iron oxide powder and iron alloy metal powder.
[19] Any one of [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. described method.
[20] The method according to any one of [1] to [19], wherein the magnetic powder contains iron alloy metal powder containing at least one selected from Si, Cr, Al, Ni, and Co.

According to the present invention, it is possible to provide a substrate manufacturing method capable of suppressing the formation of deposits and precipitates derived from magnetic powder in a magnetic layer when performing wet plating.

FIG. 1 is a schematic cross-sectional view of a core substrate as an example of a first embodiment of a substrate manufacturing method. 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 plated 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 a state in which a through-hole is filled with a through-hole filling paste 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 thermally curing 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 a state after polishing a cured product as an example of the first embodiment of the substrate manufacturing method. FIG. 7 is a schematic cross-sectional view showing how a conductor layer is formed on a polished surface as an example of the first embodiment of the substrate manufacturing method. FIG. 8 is a schematic cross-sectional view showing how a pattern 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) 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) step as an example of the second embodiment of the substrate manufacturing method. FIG. 11 is a schematic cross-sectional view for explaining the step (β) 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 of its thickness directions. 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 cut at the position indicated by the dashed-dotted 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.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing only schematically shows the shape, size and arrangement of components to the extent that the invention can be understood. The present invention is not limited by the following description, and each component can be changed as appropriate. In the drawings used for the following description, the same components are denoted by the same reference numerals, and redundant description may be omitted. Also, the configuration according to the embodiment of the present invention is not necessarily manufactured or used according to the illustrated arrangement.

Before describing the substrate manufacturing method of the present invention, the resin composition capable of forming the magnetic layer will be described.

[Resin composition]
The resin composition contains (a) magnetic powder and (b) a 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) Magnetic powders include, for example, pure iron powder; 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 system 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-based metal powder such as -Co-based alloy powder; amorphous alloys such as Co-based amorphous.

Among them, (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. Moreover, as the iron alloy metal powder, it is preferable to include 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 Powdertech; “PST-S” manufactured by Sanyo Special Steel; "AW2-08PF10F", "AW2-08PF3F", "Fe-3.5Si-4.5CrPF20F", "Fe-50NiPF20F", "Fe-80Ni-4MoPF20F"; JFE Chemical Co., Ltd. "LD-M", "LD -MH", "KNI-106", "KNI-106GSM", "KNI-106GS", "KNI-109", "KNI-109GSM", "KNI-109GS"; manufactured by Toda Kogyo "KNS-415", "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 Industries, Ltd.; "Nanotek" manufactured by CIK Nanotech; "JEMK-S" manufactured by Kinsei Matech, " JEMK-H": "Yttrium iron oxide" manufactured by ALDRICH. 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 (aspect ratio) obtained by dividing the length of the major axis of the magnetic powder by the length of the minor axis is preferably 2 or less, more preferably 1.5 or less, and still more preferably 1.2 or less. In general, the magnetic powder having a flat shape rather than a spherical shape tends to improve the relative magnetic permeability. However, it is preferable to use spherical magnetic powder, in general, from the viewpoint of reducing the 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 still more preferably 1 μm or more, from the viewpoint of improving the relative magnetic permeability. Also, it is preferably 10 μm or less, more preferably 9 μm or less, and even 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 the Mie scattering theory. Specifically, the particle size distribution of the magnetic powder is prepared on a volume basis using a laser diffraction/scattering type particle size distribution measuring apparatus, and the median diameter can be used as the average particle size for measurement. As the measurement sample, a magnetic powder dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction/scattering type particle size distribution analyzer, "LA-500" manufactured by Horiba Ltd., "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, still more preferably 0.3 m ² /g, from the viewpoint of improving the relative permeability. That's it. Also, it is preferably 10 m ² /g or less, more preferably 8 m ² /g or less, still more preferably 5 m ² /g or less. (a) The specific surface area of the magnetic powder can be measured by the BET method.

(a) The content (% by volume) of the magnetic powder is preferably 10% by volume when the non-volatile component in the resin composition is 100% by volume from the viewpoint of improving the relative magnetic permeability and reducing the loss factor. Above, more preferably 20% by volume or more, still more preferably 30% by volume or more. Also, it is preferably 85% by volume or less, more preferably 80% by volume or less, and even more preferably 75% by volume or less.

(a) The content (% by mass) of the magnetic powder is preferably 70% by mass when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of improving the relative magnetic permeability and reducing the loss factor. Above, more preferably 75% by mass or more, still more preferably 80% by mass or more. Also, it is preferably 98% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less.

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

(b) Binder resins include, for example, epoxy resins, phenolic resins, naphthol-based resins, benzoxazine-based resins, active ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, acid anhydride-based resins, and the like. thermosetting resins; 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 that is used when forming an insulating layer of a wiring board, and among these, an epoxy resin is preferable. (b) Binder resin may be used individually by 1 type, and may be used in combination of 2 or more type.
Here, phenol-based resins, naphthol-based resins, benzoxazine-based resins, active ester-based resins, cyanate ester-based resins, carbodiimide-based resins, amine-based resins, and acid anhydride-based resins react with epoxy resins. Components that can cure the resin composition are sometimes collectively referred to as a "curing agent".

-Thermosetting resin-
Epoxy resins as thermosetting resins include, for example, glycyrrol 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; type epoxy resin; phenol novolac type epoxy resin; tert-butyl-catechol type epoxy resin; naphthol novolac type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, epoxy resin having a condensed ring structure such as anthracene type epoxy resin; glycidyl Amine type epoxy resin; Glycidyl ester type epoxy resin; Cresol novolac type epoxy resin; Biphenyl type epoxy resin; Linear aliphatic epoxy resin; Epoxy resin having butadiene structure; contained epoxy resin; cyclohexanedimethanol type epoxy resin; trimethylol type epoxy resin; tetraphenylethane type epoxy resin and the like. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type. The epoxy resin is preferably one or more selected from bisphenol A type epoxy resins and bisphenol F type epoxy resins.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. Moreover, the epoxy resin preferably has an aromatic structure, and when two or more epoxy resins are used, at least one of them more preferably has an aromatic structure. Aromatic structures are chemical structures generally defined as aromatic and also include polycyclic aromatic and heteroaromatic rings. The ratio 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, and particularly preferably 70% by mass with respect to 100% by mass of the non-volatile component of the epoxy resin. % or more.

Epoxy resins include liquid epoxy resins at a temperature of 25° C. (hereinafter sometimes referred to as “liquid epoxy resins”) and solid epoxy resins at a temperature of 25° C. (hereinafter sometimes referred to as “solid epoxy resins”). ). When an epoxy resin is contained as the component (b), the epoxy resin may contain only a liquid epoxy resin, may contain only a solid epoxy resin, or may be a combination of a liquid epoxy resin and a solid epoxy resin. Although it may be contained, in the case where a large amount of magnetic powder is contained in order to increase the relative magnetic permeability, etc., from the viewpoint of preventing the viscosity of the resin composition from becoming too high and making it easier to paste, liquid epoxy resin It preferably contains only

Liquid epoxy resins include glycyrrol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins. Resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol type epoxy resins, and epoxy resins having a butadiene structure are preferred, and glycyrrol type epoxy resins, bisphenol A type epoxy resins, and bisphenol F type epoxy resins are more preferred. Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation; "828US" and "jER828EL" (bisphenol A type epoxy resins) manufactured by Mitsubishi Chemical Corporation. , "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin); "630" and "630LSD" manufactured by Mitsubishi Chemical Corporation, "ED-523T" manufactured by ADEKA (glyciroll type epoxy resin (ADEKA GLYCIROL)), "EP-3980S" (glycidylamine type epoxy resin), "EP-4088S" (dicyclopentadiene type epoxy resin); "ZX1059" (Bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-201" (cycloaliphatic glycidyl ether), "ZX1658", "ZX1658GS" (liquid 1,4-glycidylcyclohexane); "EX" manufactured by Nagase ChemteX Corporation -721" (glycidyl ester type epoxy resin); Daicel's "Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton), "PB-3600" (epoxy resin having a butadiene structure), and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Solid epoxy resins include naphthalene type tetrafunctional epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, Anthracene type epoxy resin, bisphenol A type epoxy resin and tetraphenylethane type epoxy resin are preferred, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin and biphenyl type epoxy resin are more preferred. Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), "N-690" ( cresol novolak type epoxy resin), "N-695" (cresol novolak 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); Nippon Steel Chemical & Material Co., Ltd. "ESN475V" " (naphthalene type epoxy resin), "ESN485" (naphthol novolak type epoxy resin); Mitsubishi Chemical Corporation "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), " YX8800" (anthracene type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Corporation; resin), "jER1010" (solid bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin), and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When a liquid epoxy resin and a solid epoxy resin are used together as component (b), the ratio by mass (liquid epoxy resin:solid epoxy resin) is preferably 1:0.1 to 1:0. 4, more preferably 1:0.3 to 1:3.5, 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 50 g/eq. ~3000g/eq. , more preferably 80 g/eq. ~2000 g/eq. , even more preferably 110 g/eq. ~1000g/eq. is. Within this range, the crosslink density of the cured product is sufficient, and a magnetic layer with a small surface roughness can be obtained. The epoxy equivalent can be measured according to JIS K7236, and is the mass of a resin containing one equivalent of epoxy groups.

The weight average molecular weight of the epoxy resin as the component (b) is preferably 100-5000, more preferably 250-3000, still more preferably 400-1500. Here, the weight average molecular weight of the epoxy resin is the polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

As the active ester-based resin, a resin having one or more active ester groups in one molecule can be used. Among them, active ester resins have two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, heterocyclic hydroxy compound esters, etc. Resins are preferred. The active ester resin is preferably 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, an active ester-based resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester-based resin obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred.

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

Examples of phenol 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, phloroglucine, Benzenetriol, dicyclopentadiene-type diphenol compound, phenol novolak, and the like. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Preferred specific examples of the active ester resin include an active ester resin containing a dicyclopentadiene type diphenol structure, an active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolak, and benzoyl of phenol novolak. active ester-based resins containing compounds. Among them, an active ester resin containing a naphthalene structure and an active ester resin containing a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" represents 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 type diphenol structure. 65TM", "EXB-8000L-65TM" (manufactured by DIC); "EXB9416-70BK" and "EXB-8150-65T" (manufactured by DIC) as active ester resins containing a naphthalene structure; "DC808" (Mitsubishi Chemical Co., Ltd.) as an active ester resin containing phenol novolac "YLH1026" (Mitsubishi Chemical Co., Ltd.) as an active ester resin containing a benzoylated phenol novolac "DC808" (manufactured by Mitsubishi Chemical Corporation); "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins that are benzoyl compounds of phenol novolak ); and the like.

From the viewpoint of heat resistance and water resistance, the phenolic resin and naphtholic resin preferably have a novolac structure. From the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based resin is more preferable.

Specific examples of phenol-based resins and naphthol-based 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”, Nippon Steel Chemical & Materials “SN170”, “SN180”, “SN190”, “SN475”, “SN485”, “SN495”, “SN-495V”, “SN375”, “SN395 ”, DIC “TD-2090”, “LA-7052”, “LA-7054”, “LA-1356”, “LA-3018-50P”, “EXB-9500” and the like.

Specific examples of benzoxazine-based resins include "JBZ-OD100" (benzoxazine ring equivalent: 218), "JBZ-OP100D" (benzoxazine ring equivalent: 218), "ODA-BOZ" (benzoxazine ring equivalent) manufactured by JFE Chemical Co., Ltd. Equivalent 218); "Pd" (benzoxazine ring equivalent 217), "Fa" (benzoxazine ring equivalent 217) manufactured by Shikoku Kasei Kogyo Co., Ltd.; "HFB2006M" (benzoxazine ring equivalent 432) and the like.

Examples of cyanate ester resins include bisphenol A dicyanate, polyphenolcyanate, oligo(3-methylene-1,5-phenylenecyanate), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4,4' -ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanate-3,5-dimethylphenyl ) bifunctional 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 obtained by partially triazinizing these cyanate resins; and the like. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins) manufactured by Lonza Japan, "ULL-950S" (polyfunctional cyanate ester resins), "BA230", "BA230S75" (a prepolymer in which part or all of bisphenol A dicyanate is triazined to form a trimer) and the like.

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

Amine-based resins include resins having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. Among them, aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. The amine-based resin is preferably a primary amine or a secondary amine, more preferably a primary amine. Specific examples of amine-based curing agents include 4,4′-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, and 3,3′. -diaminodiphenyl sulfone, 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, bis(4-(3-aminophenoxy)phenyl)sulfone, and the like. Commercially available amine-based resins may be used. AS", Mitsubishi Chemical's "Epicure W", and the like.

Acid anhydride resins 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, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl Sulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1, Polymer type acid anhydrides such as 3-dione, ethylene glycol bis(anhydrotrimellitate), styrene/maleic acid resin obtained by copolymerizing styrene and maleic acid, and the like can be mentioned.

When an epoxy resin and a curing agent are contained 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, 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 the non-volatile component of the epoxy resin present in the resin composition by the epoxy equivalent. The "number of active groups in the curing agent" is the sum of all the values obtained by dividing the mass of the non-volatile component of the curing agent present in the resin composition by the active group equivalent.

-Thermoplastic resin-
The polystyrene equivalent weight average molecular weight of the thermoplastic resin is preferably 30,000 or more, more preferably 50,000 or more, and still more preferably 100,000 or more. Also, it is preferably 1,000,000 or less, more preferably 750,000 or less, and still more preferably 500,000 or less. The polystyrene equivalent weight average molecular weight of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight average molecular weight of the thermoplastic resin is measured by Shimadzu Corporation's "LC-9A/RID-6A" as a measuring device, and Showa Denko's "Shodex K-800P/K-804L" as a column. /K-804L" can be calculated by using chloroform or the like as a mobile phase, measuring the column temperature at 40° C., and 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. and a phenoxy resin having one or more skeletons selected from the group consisting of a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. A phenoxy resin may be used individually by 1 type, or 2 or more types may be used together. 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" (bisphenolacetophenone). Skeleton-containing phenoxy resin), and in addition, "FX280" and "FX293" manufactured by Nippon Steel Chemical & Materials Co., Ltd., "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30" manufactured by Mitsubishi Chemical Corporation, Examples include "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482".

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

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 weight 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 having a glass transition temperature of 25°C or less, an epoxy group-containing acrylic acid ester copolymer resin having a glass transition temperature of 25°C or less is preferable. -80H” (epoxy group-containing acrylate 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 Corporation (epoxy group-containing acrylate 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 resins and butyral resins include Denka Butyral "4000-2", "5000-A", "6000-C" and "6000-EP" manufactured by Denki Kagaku Kogyo Co., Ltd., manufactured by Sekisui Chemical Co., Ltd. S-lec BH series, BX series, KS series such as "KS-1", BL series such as "BL-1", BM series and the like.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika. Specific examples of polyimide resins also include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds and tetrabasic acid anhydrides (polyimides described in JP-A-2006-37083), and polysiloxane skeletons. Examples include modified polyimides such as polyimide containing (polyimides described in JP-A-2002-12667 and JP-A-2000-319386).

Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamideimide resins include modified polyamideimides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamideimides) manufactured by Hitachi Chemical Co., Ltd.

Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., and the like. Specific examples of the polyphenylene ether resin include vinyl group-containing oligophenylene ether/styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Company, Inc.

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

Among them, 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 based on the assumption that the non-volatile component in the resin composition is 100% by mass, from the viewpoint that (a) the magnetic powder can be dispersed and bound in the resin composition to form a magnetic layer. , preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more. The upper limit is not particularly limited as long as the effects of the present invention are exhibited, but is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less.

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

(c) Dispersants include, for example, phosphate ester dispersants such as polyoxyethylene alkyl ether phosphoric acid; anionic dispersants such as sodium dodecylbenzene 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. and nonionic dispersants. Among these, anionic dispersants are preferred. Dispersants may be used singly or in combination of two or more.

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

Examples of organosiloxane-based dispersants include commercially available products such as "BYK347" and "BYK348" manufactured by BYK-Chemie.

As polyoxyalkylene-based dispersants, commercially available products include NOF's "MALIALIM" series "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F" and "SC-0708A". ”, and “HKM-50A”. Polyoxyalkylene dispersants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene alkylamides, etc. It is a generic term.

Acetylene glycol is commercially available from Air Products and Chemicals Inc.; "Surfinol" series "82", "104", "440", "465" and "485", and "Olefin Y".

(c) The content of the dispersant is preferably 0.1% by mass or more, more preferably 0% by mass, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of significantly exhibiting the effects of the present invention. 0.2% 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, and even 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 advanced, and the mechanical strength of the cured product can be enhanced. (d) Curing accelerators include, for example, 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-based curing accelerator or an imidazole-based curing accelerator, and more preferably an imidazole-based curing agent. The curing accelerator may be used singly or in combination of two or more.

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

As the amine-based curing accelerator, a commercially available product may be used, and examples thereof include "PN-50", "PN-23", and "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd.

Examples of imidazole 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 isocyanurate, 2-phenylimidazole isocyanurate, 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 the like, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

As the imidazole-based curing accelerator, a commercially available product may be used, for example, "2MZA-PW" and "2PHZ-PW" manufactured by Shikoku Kasei Kogyo Co., Ltd., and "P200-H50" manufactured by Mitsubishi Chemical Corporation. .

Phosphorus curing accelerators include, for example, triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate, and triphenylphosphine and tetrabutylphosphonium decanoate are preferred.

Guanidine curing accelerators include, for example, 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 and the like, with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. organic zinc complexes such as iron (III) acetylacetonate; organic nickel complexes such as nickel (II) acetylacetonate; organic manganese complexes such as manganese (II) acetylacetonate; Examples of organic metal salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

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

(d) The content of the curing accelerator is preferably 0.1% by mass or more, more preferably 0.1% by mass or more, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of lowering the viscosity of the resin composition. 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, and even more preferably 1% by mass or less.

<(e) other additives>
The resin composition may further contain (e) other additives as needed. Examples of such other additives include curing retardants such as triethyl borate, flame retardants, thickeners, antifoaming agents, leveling agents, adhesion imparting agents, and resin additives such as coloring agents. be done.

<Method for producing resin composition>
The resin composition can be produced, for example, by a method of stirring the ingredients using a stirring device such as a three-roll mixer, a rotating mixer, or a high-speed rotating mixer. The resin composition may be defoamed after production or the like. Examples thereof include defoaming by standing, defoaming by centrifugation, vacuum defoaming, stirring defoaming, and combinations thereof.

In forming the magnetic layer of the substrate, the resin composition may be used in the form of a pasty 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 still more preferably 0.5% by mass, relative to the total mass of the magnetic paste. Below, it is 0.1 mass % or less especially preferably. Although the lower limit is not particularly limited, it is 0.001% by mass or more, or not contained. To suppress the generation of voids due to volatilization of the organic solvent by reducing the content of the organic solvent in the magnetic paste or not containing the organic solvent, and furthermore to make the paste excellent in handleability 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, still more preferably 30 Pa·s or more and 50 Pa·s or more, and usually less than 200 Pa·s, preferably 180 Pa·s. Below, more preferably 160 Pa·s or less. The viscosity can be measured by keeping the temperature of the magnetic paste at 25±2° C. and using an E-type viscometer.

[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, even more preferably 150 μm or less and 100 μm or less, from the viewpoint of thinning. Although the lower limit of the thickness of the resin composition layer is not particularly limited, it 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 preferable.

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

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal of copper may be used, and 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. The release agent used in the release layer of the release layer-attached support includes, for example, 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, for example, "SK-1" manufactured by Lintec Co., Ltd., "SK-1", " AL-5", "AL-7", Toray's "Lumirror T60", Teijin's "Purex", and Unitika's "Unipeel".

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. When a release layer-attached support is used, the thickness of the release layer-attached support as a whole is preferably within the above range.

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

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK) and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate and other acetates, cellosolve and butyl carbitol. carbitols, aromatic hydrocarbons such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone. An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

Drying may be carried out 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 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% by mass to 60% by mass of the organic solvent, drying at 50 ° C. to 150 ° C. for 3 minutes to 10 minutes The resin composition layer can be formed.

In the magnetic sheet, a protective film conforming to the support can 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). Although the thickness of the protective film is not particularly limited, it is, for example, 1 μm to 40 μm. By laminating the protective film, the surface of the resin composition layer can be prevented from being dusted or scratched. The magnetic sheet can be wound into a roll and stored. When the magnetic sheet has a protective film, it can be used by peeling off the protective film.

[Substrate manufacturing method]
A substrate manufacturing method of the present invention is a substrate manufacturing method in which a conductor layer is formed by wet plating on a magnetic layer containing magnetic powder,
(A) an acid treatment step of treating the surface of the magnetic layer with an acid solution; and (B) a step of forming a conductor layer on the magnetic layer whose surface has been treated with the acid solution.

In order to form a conductor layer by wet plating, for example, a conditioning process in which the surface of the magnetic layer is treated with a surfactant, a micro-etching process in which the surfactant is removed from areas where the surfactant is not required, and a catalyst is applied to the surface of the magnetic layer. , a catalyst activation step of activating the catalyst, and a step of forming a conductor layer on the magnetic layer.

Magnetic powder has the property of being easily dissolved in acid, unlike inorganic fillers such as silica. Therefore, when the liquid used in the micro-etching process is acidic, the magnetic powder dissolved in the liquid forms precipitates and precipitates (hereinafter referred to as "precipitates and precipitates") under alkaline conditions in the catalytic process. may be collectively referred to as insoluble matter, etc.) is generated. In addition, in the catalyst activation step, an acidic reducing agent solution is usually used to activate the catalyst. As a result, a large amount of insoluble matter and the like are generated in the reducing bath. As the content of the magnetic powder increases, a larger amount of insoluble matter and the like is generated, contaminating the reducing bath and the substrate.

In contrast, the present invention includes (A) an acid treatment step of treating the surface of the magnetic layer with an acid solution. By dissolving the magnetic powder present on the surface of the magnetic layer with an acid solution, it is possible to reduce the amount of magnetic powder on the surface of the magnetic layer that may cause insoluble matter, etc., and as a result, the catalytic process and catalytic activity are improved. It is possible to suppress the generation of insoluble matter and the like generated in the curing step. Furthermore, even after the step (A), there is usually no peeling or swelling at the interface between the conductor layer and the magnetic layer obtained, and the peel strength is the same as when the step (A) is not performed. Further, the substrate obtained by the manufacturing method through the step (A) can usually improve the relative magnetic permeability and reduce the loss factor in the frequency range of 10 to 200 MHz. The mechanism described above can be applied to methods other than the substrate manufacturing method including the steps illustrated above.

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

<First embodiment>
In the substrate manufacturing method of the first embodiment, it is preferable to perform the step of preparing a substrate having a magnetic layer before performing the step (A).

The step of preparing a substrate having a magnetic layer in the first embodiment of the substrate manufacturing method includes:
(1) preferably includes a step of filling the through-holes with a resin composition and curing the resin composition to form a magnetic layer;
(1) After the process (A) Before the process,
(2) It is more preferable to further include the step of polishing the surface of the magnetic layer.

-(1) Process-
(1) In performing 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 a magnetic paste.

Further, in performing the step (1), as shown in FIG. 1, a supporting substrate 11, first metal layers 12 made of metal such as copper foil provided on both surfaces of the supporting substrate 11, and first A step of preparing a core substrate 10 with two metal layers 13 may be included. 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.

Moreover, as an example is shown in FIG. 2, a step of forming through holes 14 in the core substrate 10 may be included. The through holes 14 can be formed by drilling, laser irradiation, plasma irradiation, or the like, for example. Specifically, the through hole 14 can be formed by forming a through hole in the core substrate 10 using a drill or the like.

Formation of the through holes 14 can be carried out using commercially available drilling equipment. Examples of commercially available drilling devices include "ND-1S211" manufactured by Hitachi Via Mechanics.

After the through-holes 14 are formed in the core substrate 10, the core substrate 10 is roughened as shown in FIG. A step of forming a plating layer 20 on the surface of 13 may be included.

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

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

After preparing the core substrate 10 with the plating layer 20 formed in the through holes 14, the through holes 14 are filled with a resin composition 30a as shown in FIG. Examples of filling methods include a method of filling the through holes 14 with the resin composition 30a via a squeegee, a method of filling the resin composition 30a via a cartridge, a method of mask printing and filling the resin composition 30a, A roll coating method, an inkjet method, and the like can be mentioned. The resin composition 30a is preferably 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 in the through-hole 14 as shown in FIG. The thermosetting conditions for the resin composition 30a vary depending on the composition and type of the resin composition 30a. It is 240° C. or lower, more preferably 220° C. or lower, still more preferably 200° C. or lower. The curing time of the resin composition 30a is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, preferably 120 minutes or shorter, more preferably 100 minutes or shorter, and still more preferably 90 minutes or shorter. is.

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

Before thermally curing the resin composition 30a, the resin composition 30a may be subjected to a preheating 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 usually heated at a temperature of 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).

-(2) Process-
In the step (2), as an example is shown in FIG. 6, the excess magnetic layer 30 protruding from or adhering to the core substrate 10 is removed by polishing and planarized. As a polishing method, a method capable of polishing surplus magnetic layers 30 protruding from or adhering to the core substrate 10 can be used. Examples of such a polishing method include buffing and belt polishing. Commercially available buffing devices include "NT-700IM" manufactured by Ishii Hokumon Co., Ltd., and the like.

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 still 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, still more preferably 800 nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

(2) After the step (A) before the step (A), a heat treatment step may be carried out, 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, preferably 120° C. or higher, more preferably 130° C. or higher, still more preferably 150° C. or higher, preferably 240° C. or lower, more preferably 220° C. or lower. , and more preferably 200° C. or less. The heat treatment time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and preferably 90 minutes or shorter, more preferably 70 minutes or shorter, still more preferably 60 minutes or shorter.

-(A) Acid treatment step of treating the surface of the magnetic layer with an acid solution-
The step (A) is a step of treating the surface of the magnetic layer with an acid solution. Specifically, the magnetic layer surface is brought into contact with an acid solution. This treatment can remove the magnetic powder on the surface of the magnetic layer. Therefore, it becomes possible to suppress the generation of insoluble matter and the like.

As the acid solution, one that can dissolve the magnetic powder can be used. An inorganic acid can be used as such an acid solution. Inorganic acids include, for example, hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. Among them, from the viewpoint of effectively dissolving the magnetic powder, at least one selected from hydrochloric acid, sulfuric acid and nitric acid is preferable, and hydrochloric acid is more preferable.

The concentration of the acid solution varies depending on the type of acid, but from the viewpoint of suppressing the generation of insoluble matter, the normality is preferably 3N or more, more preferably 5N or more, further preferably 6N or more, 7N or more, or 8N. Above, it is 10N or more, preferably 40N or less, more preferably 36N or less, still more preferably 30N or less, 20N or less, and 15N or less.

The temperature of the acid solution is preferably 10° C. or higher, more preferably 15° C. or higher, still more preferably 20° C. or higher, and preferably 100° C. or lower, more preferably 70° C., from the viewpoint of suppressing the generation of insoluble matter. °C or less, more preferably 60°C or less.

The step (A) is performed by immersing the magnetic layer in an acid solution. The immersion time is preferably 1 minute or longer, more preferably 3 minutes or longer, still more preferably 5 minutes or longer, and preferably 60 minutes or shorter, more preferably 45 minutes or shorter, from the viewpoint of suppressing the generation of insoluble matter. , and more preferably 30 minutes or less.

When the magnetic powder present on the surface of the magnetic layer is dissolved in an acid solution, the color of the surface of the magnetic layer changes. Specifically, the surface of the magnetic layer before the step (A) has the color of the magnetic powder. color becomes visible. The step (A) may be terminated when the color of the magnetic layer surface changes and the color of the magnetic powder becomes invisible.

(A) After completion of the step, water washing treatment may be performed as necessary.

After the (A) step, a step of forming a conductor layer on the magnetic layer surface-treated with (B) an acid solution is performed by wet plating.
(3) preferably includes a conditioning step of treating the surface of the magnetic layer with a solution containing a surfactant;
(3) After the process (B) Before the process,
It is more preferable to further include (4) a catalyzing step of applying a catalyst to the surface of the magnetic layer, and (5) a catalyst activating step of activating the catalyst in this order.

In addition, after the (3) process and before the (4) process,
(3-1) It may include a micro-etching step of removing the surfactant from sites where the surfactant is unnecessary.

By performing the steps (3) to (5) after the step (A) is completed, it is possible to suppress the generation of insoluble matter, etc., which is generated particularly in the steps (4) and (5).

-(3) Process-
In the step (3), the surface of the magnetic layer is usually washed by contacting the surface of the magnetic layer with a solution containing a surfactant, and the surface charge is adjusted so as to facilitate the adsorption of the catalyst in the step (4). do.

The surfactant-containing solution used in the step (3) contains a surfactant capable of washing the surface of the magnetic layer and adjusting the surface charge so as to facilitate adsorption of the catalyst in the step (4). A solution can be used. Examples of such a solution include an alkaline solution containing a surfactant, an acid solution containing a surfactant, and the like. From the viewpoint of suppressing insoluble matter, etc., an alkaline solution containing a surfactant is preferable.

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

Examples of surfactants include cationic surfactants such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts; fatty acid salts such as sodium oleate, alkyl sulfate salts, alkylbenzenesulfonates, and alkyl sulfosuccinates; Anionic surfactants such as acid salts, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkane sulfonate sodium salts, alkyldiphenyl ether sulfonate sodium salts; polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene Nonionic surfactants such as styrylphenyl ether, polyoxyethylene octiphenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene/polyoxypropylene copolymers are included.

A commercially available product can be used as the surfactant. Examples of commercially available products include "Seculigand 902" manufactured by Atotech Japan, "PED-104" manufactured by Uemura Kogyo Co., Ltd., and the like.

The treatment time in step (3) is preferably 1 minute or longer, more preferably 2 minutes or longer, still more preferably 3 minutes or longer, and more preferably 20 minutes or shorter, more preferably, from the viewpoint of facilitating adsorption of the catalyst. 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, still more preferably 50° C. or higher, and preferably 90° C. or lower, from the viewpoint of facilitating adsorption of the catalyst. It is preferably 80° C. or lower, more preferably 70° C. or lower.

(3) After completion of the process, water washing treatment may be performed as necessary.

-(3-1) Process-
In the step (3-1), the surfactant is removed from the sites where the surfactant is not needed, usually by bringing the microetching liquid into contact with the surface of the magnetic layer. A copper foil substrate etc. are mentioned as a site|part which does not require a surfactant, for example.

Examples of the micro-etching liquid include hydrochloric acid, sulfuric acid, hydrogen peroxide solution, sodium persulfate, ammonium persulfate, and a combination 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 sites. From the viewpoint of facilitating removal, it is preferably 0.1 N or more, more preferably 0.2 N or more, and still more preferably 0.5 N or more.

The temperature of the microetching solution is preferably 10° C. or higher, more preferably 15° C. or higher, still more preferably 20° C. or higher, and more 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 step (3-1) is preferably 10 seconds or longer, more preferably 15 seconds or longer, still more preferably 30 seconds or longer, and preferably 60 seconds, from the viewpoint of facilitating the removal of the surfactant. Below, more preferably 50 seconds or less, still more preferably 40 seconds or less.

(3-1) After completion of the step, water washing treatment may be performed as necessary.

-(4) Process-
In step (4), the adhesion between the magnetic layer and the conductor layer can be improved by applying a catalyst to the surface of the magnetic layer. Usually, in step (4), the magnetic layer is immersed in a solution containing a catalyst to adsorb the catalyst 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.

An alkaline solution is usually used as the solution containing the catalyst. As a result, the generation of insoluble matter and the like can be remarkably suppressed. The pH of this alkaline solution is preferably higher than 7, more preferably 8 or higher, and still more preferably 10 or higher. Although the upper limit is not particularly limited, it may preferably be 14 or less, 13 or less, or the like.

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

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

The treatment time in step (4) is preferably 1 minute or longer, more preferably 2 minutes or longer, even more preferably 3 minutes or longer, and preferably 20 minutes or shorter, from the viewpoint of adsorbing the catalyst to the entire magnetic layer. It is preferably 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, still more preferably 30° C. or higher, and preferably 60° C. or lower, from the viewpoint of adsorbing the catalyst to the entire magnetic layer. It is preferably 50° C. or lower, more preferably 40° C. or lower.

(4) After completion of the process, water washing treatment may be performed as necessary.

-(5) Process-
In step (5), the adhesion between the magnetic layer and the conductor layer can be improved by activating the catalyst. Usually, in step (5), the magnetic layer provided with the catalyst is immersed in a reducing agent solution to generate catalyst nuclei and activate the catalyst provided on the surface of the magnetic layer.

Examples of the reducing agent used in step (5) include hypophosphite, a mixed solution of dimethylamine borane and a potassium salt of an organic acid, and the like.

An acidic solution is usually used as the reducing agent solution. As a result, the generation of insoluble matter and the like can be remarkably suppressed. The pH of this acidic solution is preferably 1 or higher, more preferably 2 or higher, and still more preferably 3 or higher. Although the upper limit is not particularly limited, it can be preferably less than 7, 6 or less.

From the viewpoint of activating the catalyst applied to the surface of the magnetic layer, 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 still more preferably It is 0.5N or more, preferably 3N or less, more preferably 2N or less, further preferably 1N or less.

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

From the viewpoint of activating the catalyst, the treatment time in step (5) is preferably 1 minute or longer, more preferably 2 minutes or longer, still more preferably 3 minutes or longer, and preferably 20 minutes or shorter, more preferably 15 minutes. minutes or less, 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, still more preferably 30° C. or higher, and preferably 60° C. or lower, more preferably 50° C. or lower. , and more preferably 40° C. or less.

(5) After completion of the process, water washing treatment may be performed as necessary.

-(B) Process-
In the step (B), as shown in FIG. 7, a conductor layer 40 is formed by wet plating on the magnetic layer 30 whose surface has been treated with an acid solution in the step (A). Further, after the conductor layer 40 is formed, as shown in FIG. 8, the conductor layer 40, the first metal layer 12, the second metal layer 13, and the plating layer 20 are partially removed by etching or the like. A pattern conductor layer 41 may be formed.

Materials for the conductor layer include 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, or nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys can be used from the viewpoint of versatility, cost, ease of patterning, and the like. Chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloys are preferably used, and copper is even more preferred.

In a preferred embodiment of step (B), electroless plating is preferably performed to form a conductor layer, and after electroless plating is performed, electroplating is further performed to form a conductor layer. more preferred. Therefore, in step (B), it is preferable to form a conductive layer by plating the surface of the magnetic layer by a semi-additive method, a full-additive method, or the like. In the step (B), the conductor layer is preferably formed by a semi-additive method from the viewpoint of facilitating the production of the conductor layer.

In the details of the semi-additive method, first, a plating seed layer is formed 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 a conductor layer on the exposed plating seed layer by electroplating, the mask pattern is removed. After that, the unnecessary plating seed layer is removed by etching or the like, and a conductor layer having a desired wiring pattern can be formed.

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, electroless nickel plating, electroless nickel-tungsten plating, electroless tin plating, electroless gold plating, etc. Electroless copper plating is preferred.

Electroless plating solutions used in electroless plating include, for example, solutions containing metal ions such as copper, nickel, tungsten, tin, gold, palladium, and _PdCl2 . In addition, 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. Examples of commercially available products include "Surucup PEA" manufactured by Uemura Kogyo Co., Ltd. and "S-KPD" manufactured by Nippon Kanigen Co., Ltd.

The treatment time of the electroless plating treatment is preferably 10 minutes or longer, more preferably 20 minutes or longer, still more preferably 30 minutes or longer, preferably 60 minutes or shorter, more preferably 50 minutes or longer, from the viewpoint of activating the catalyst. 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, still more preferably 30° C. or higher, and more preferably 60° C. or lower, more preferably, from the viewpoint of efficiency of conductor layer formation. is 55° C. or less, more preferably 50° C. or less.

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 corresponding to a desired wiring pattern, thereby forming a mask pattern. Exposure and development conditions can be 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 and acrylic resins.

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

Electroplating is performed by immersing the magnetic layer after electroless plating in a plating bath. At that time, an electric current is applied to the plating bath. Examples of the electrolytic plating treatment include electrolytic copper plating, electrolytic nickel plating, electrolytic tin plating, electrolytic gold plating, etc. Electrolytic copper plating is preferred.

Plating baths used for electrolytic plating include baths containing copper sulfate, copper pyrophosphate, copper cyanide, and the like.

The treatment time of the electroplating treatment is preferably 30 minutes or longer, more preferably 40 minutes or longer, still more preferably 50 minutes or longer, preferably 90 minutes or shorter, more preferably 80 minutes, from the viewpoint of activating the catalyst. 70 minutes or less, more preferably 70 minutes or less.

The treatment temperature of the electroplating treatment is preferably 10° C. or higher, more preferably 15° C. or higher, still more preferably 20° C. or higher, and preferably 50° C. or lower, more preferably 50° C. or lower, from the viewpoint of efficiency of conductor layer formation. 40° C. or less, more preferably 30° C. or less.

The current density of the electroplating treatment is preferably 1.0 A/dm ² or more, more preferably 1.5 A/dm ² or more, still more preferably 2.0 A/dm ² or more, from the viewpoint of efficiency of conductor layer formation. , preferably 4.0 A/dm ² or less, more preferably 3.5 A/dm ² or less, still more preferably 3.0 A/dm ² or less.

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

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

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

In the substrate manufacturing method of the second embodiment, it is preferable to perform the step of preparing a substrate having a magnetic layer before performing the step (A). In the second embodiment, it is preferable to form the magnetic layer using a magnetic sheet.

The step of preparing a substrate having a magnetic layer in the second embodiment of the substrate manufacturing method includes:
(α) Laminating the magnetic sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate, and thermosetting the resin composition layer to form a magnetic layer, and (β) Drilling the magnetic layer. preferably comprising the step of
(γ) It may further include a roughening step of roughening the surface of the magnetic layer.

-(α) Process-
(α) In performing the step, a step of preparing a magnetic sheet may be included. The magnetic sheet is as explained above.

In the step (α), as shown in an example in FIG. 9, a magnetic sheet 310 including a support 330 and a resin composition layer 320a provided on the support 330 is placed on the inner layer substrate. 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 materials for the inner layer substrate 200 include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer board 200 may be an inner layer circuit board in which wiring and the like are formed within its thickness.

As an example is shown in FIG. 9, the inner 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 wirings. In the illustrated example, only the wiring forming 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 or the like (not shown). The external terminals 240 can be configured as part of a conductor layer provided on the second main surface 200b.

Conductive materials that can form the first conductor layer 420, the external terminal 240, and other conductor layers are the same as the materials for the conductor layers described in the "-(B) step-" section of the first embodiment.

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

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

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

The bonding between the resin composition layer 320a and the inner substrate 200 can be performed, for example, by thermocompression bonding the magnetic sheet 310 to the inner substrate 200 from the support 330 side. As a member for thermocompression bonding the magnetic sheet 310 to the inner layer substrate 200 (hereinafter also referred to as a “thermocompression member”), for example, a heated metal plate (stainless steel (SUS) end plate, etc.) or a metal roll (SUS roll), etc. is mentioned. Instead of directly contacting the thermocompression bonding member with the magnetic sheet 310 and pressing it, a sheet made of an elastic material such as heat-resistant rubber is used so that the magnetic sheet 310 can sufficiently follow the unevenness of the surface of the inner layer substrate 200 . It is preferable to press through

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 0.5° C. It is in the range of 098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, and the time for thermocompression bonding is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Bonding of the magnetic sheet and the inner layer substrate is preferably performed under reduced pressure conditions of 26.7 hPa or less.

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

After bonding the magnetic sheet 310 and the inner layer substrate 200, the stacked magnetic sheets 31 may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. . The pressing conditions for the smoothing treatment may be the same as the thermocompression bonding conditions for the lamination described above. Smoothing treatment can be performed with a commercially available laminator. Note that the lamination and the 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 the magnetic layer. As an example is shown in FIG. 10, the resin composition layer 320a bonded to the inner substrate 200 is thermally cured to form the first magnetic layer 320. As shown in FIG. The heat curing conditions are the same as the heat curing conditions described in the section "-(1) Step-" of the first embodiment.

The support 330 may be removed between the step (α) after thermal curing and the step (β), or may be peeled off after the step (β).

In addition, the step (α) may be performed by directly coating or printing a paste resin composition on the inner layer substrate instead of laminating the magnetic sheet on the inner layer substrate.

-(β) step-
In the step (β), as shown in FIG. 11, the first magnetic layer 320 is drilled to form a via hole 360 . The via hole 360 serves as a path for electrically connecting the first conductor layer 420 and a second conductor layer 440, which will be described later. The formation of the via hole 360 can be performed by the same method as the formation of the through hole described in the section "-(1) Process-".

-(γ) process-
After the (β) step, (γ) a roughening step may be performed to roughen the surface of the magnetic layer. As the roughening method in the (γ) step, the same polishing as described in the “-(2) step-” section of the first embodiment can be performed.

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

-(A) Process-
The step (A) is a step of treating the surface of the first magnetic layer with an acid solution. By treating the surface of the magnetic layer with an acid solution, it is possible to suppress the generation of insoluble matter. The step (A) is as described in the first embodiment.

After the (A) step, a step of forming a conductor layer on the magnetic layer surface-treated with (B) an acid solution is performed by wet plating.
(3) preferably includes a conditioning step of treating the surface of the magnetic layer with a solution containing a surfactant;
(3) After the process (B) Before the process,
It is more preferable to further include (4) a catalyzing step of applying a catalyst to the surface of the magnetic layer, and (5) a catalyst activating step of activating the catalyst in this order.

In addition, after the (3) process and before the (4) process,
(3-1) It may include a micro-etching step of removing the surfactant from sites where the surfactant is unnecessary. Steps (3) to (5) are as described in the first embodiment.

-(B) Process-
In the step (B), as shown in FIG. 12, the second conductor layer 440 is formed on the first magnetic layer 320 whose surface has been treated with an acid solution in the step (A). The method for forming the second conductor layer 440 is as described in the first embodiment. In this process, via-hole wiring 360a is also formed in the via-hole 360. Next, as shown in FIG. The conductor layer 400 is formed by forming the second conductor layer 440 . The second conductor layer 440 includes multiple wirings.

A 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 multi-layer structure in which two or more single metal layers or alloy layers made of different kinds of metals or alloys are laminated. When the second conductor layer 440 has a multi-layer 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 a nickel-chromium alloy. Also, the thickness of the second conductor layer 440 is the same as the thickness of the first conductor layer 420 .

The first conductor layer 420 and the second conductor layer 440 may be spirally provided, 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 in-via-hole wiring 360a. It is 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 the in-via-hole wiring 360a. Therefore, the other end of the spiral wiring portion of the second conductor layer 440 on the outer peripheral side is electrically connected to the external terminal 240 via the via-hole wiring 360a, the land 420a, and the through-hole wiring 220a.

The coil-shaped conductive structure 400 includes a spiral wiring portion that is a portion of the first conductor layer 420, a spiral wiring portion that is a portion of the second conductor layer 440, and a spiral wiring portion of the first conductor layer 420. and 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. Specifically, as shown in an example in FIG. 14, the second magnetic layer is formed on the first magnetic layer 320 on which the second conductor layer 440 and the in-via-hole wiring 360a are formed. The second magnetic layer may be formed by steps similar to those already described.

<Physical properties of substrate>
Since the substrate manufacturing method of the present invention includes the step (A), it exhibits the characteristic that the amount of insoluble matter and the like in the electroless plating process can be suppressed. The amount of precipitates such as insoluble matter is preferably less than 300 mg/L, more preferably 250 mg/L or less, and even more preferably 210 mg/L or less. Although the lower limit is not particularly limited, it may be 0.001 mg/L or more. The amount of insolubles and the like can be measured according to the method described in Examples below.

In the substrate manufactured through the (A) process, the peel strength between the conductor layer and the magnetic layer formed by plating is generally the same as the magnetic layer and the conductor layer of the substrate manufactured without the (A) process. It exhibits properties that are equivalent to the peel strength between That is, the peel strength is not deteriorated even if the acid treatment in the step (A) is performed. The peel strength is preferably 0.05 kgf/cm or more, more preferably 0.1 kgf/cm or more, and still more preferably 0.2 kgf/cm or more. Although the upper limit is not particularly limited, it may be 10 kgf/cm or less. The peel strength can be measured according to the method described in Examples below.

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

[Inductor substrate]
The inductor substrate includes a substrate obtained by the substrate manufacturing method of the present invention. When the inductor substrate includes the substrate obtained by the first embodiment of the substrate manufacturing method, the inductor substrate has an inductor element formed of a conductor at least partially around the cured resin composition. As such an inductor substrate, for example, the one disclosed in Japanese Patent Application Laid-Open No. 2016-197624 can be applied.

When the substrate obtained by the second embodiment of the substrate manufacturing method is included, the inductor substrate includes a magnetic layer that is a cured product of a resin composition (resin composition layer), and at least a portion of which is embedded in the magnetic layer. a conductive structure formed by the conductive structure and a portion of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. It contains an inductor element. Here, FIG. 13 is a schematic plan view of the inductor substrate containing the inductor element as viewed from one of its thickness directions. FIG. 14 is a schematic diagram showing a cut end face of the inductor substrate cut at the position indicated by the dashed-dotted line II-II. FIG. 15 is a schematic plan view for explaining the configuration of the first conductor layer of the inductor substrate.

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

From FIG. 14, the first magnetic layer 320 and the second magnetic layer 340 constitute the magnetic section 300 which can be viewed as an integrated magnetic layer. Therefore, the coil-shaped conductive structure 400 is provided so that at least a portion thereof is embedded in the magnetic portion 300 . That is, in the inductor substrate 100 of the present embodiment, the inductor element includes the coil-shaped conductive structure 400 and the magnetic portion 300 extending in the thickness direction of the magnetic portion 300 and surrounded by the coil-shaped conductive structure 400. It is composed of a core part which is a part of the

As shown in FIG. 15 as an example, the first conductor layer 420 has a spiral wiring portion for forming the coil-shaped conductive structure 400 and a rectangular wiring portion electrically connected to the through-hole wiring 220a. land 420a. In the illustrated example, the spiral wiring portion includes a bent portion that bends at right angles to the straight portion and a bypass portion that bypasses the land 420a. In the illustrated example, the spiral wiring portion of the first conductor layer 420 has a substantially rectangular outline as a whole, 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 coil-shaped conductive structure 400 . In FIG. 13 or FIG. 14, the spiral wiring portion includes a linear portion and a bent portion bent at right angles. In FIG. 13 or FIG. 14, the spiral wiring portion of the second conductor layer 44 has a generally rectangular outline as a whole, and has a shape that is wound clockwise from the center toward the outside.

Such an inductor substrate can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer substrate. Also, such a wiring board can be used as chip inductor components obtained by individualizing, and can also be used as a printed wiring board in which the chip inductor components are surface-mounted.

Also, using such a wiring board, various types of semiconductor devices can be manufactured. A semiconductor device including such a wiring board can be suitably used for electric products (eg, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (eg, motorcycles, automobiles, trains, ships, aircraft, etc.). .

EXAMPLES The present invention will be specifically described below by way of 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>
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.) 15 parts by mass, reactive diluent ("ZX-1658", cycloaliphatic Diglydyl ether, manufactured by Nippon Steel Chemical & Materials Co., Ltd.) 5 parts by mass, dispersant ("RS-710", polymer anionic dispersant, manufactured by Toho Chemical Co., Ltd.) 1 part by mass, curing accelerator ("2MZA-PW" , imidazole-based curing accelerator, manufactured by Shikoku Kasei Co., Ltd.) 1 part by mass, and 150 parts by mass of magnetic powder (“M05S”, Fe—Mn ferrite, average particle size 3 μm, manufactured by Powdertech Co., Ltd.) are mixed to form a paste. A resin composition was prepared.

As a printed substrate, both sides of a glass cloth-based epoxy resin double-sided copper clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, R1515A manufactured by Matsushita Electric Works) were etched with a microetching agent (CZ8100 manufactured by MEC) to a thickness of 1 μm. A copper plate was prepared by etching to roughen the copper surface. The prepared resin composition was uniformly coated on the prepared printed substrate with a doctor blade to form a paste layer having a thickness of about 120 μm. The paste layer was heated at 130° C. for 30 minutes and further heated at 145° C. for 30 minutes for thermosetting to form 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 prepared substrate was cut into 5 cm squares and immersed in 12N hydrochloric acid at 25° C. for 10 minutes. This substrate was used as an evaluation substrate.

<Example 2>
In Example 1, 150 parts by mass of magnetic powder (“M05S”, Fe—Mn ferrite, average particle size 3 μm, manufactured by Powdertech) was added to magnetic powder (“AW2-08PF3F”, Fe—Cr—Si system The alloy (amorphous), average particle size 3 μm, manufactured by Epson Atmix) was changed to 210 parts by mass. An evaluation substrate was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 1>
In Example 1, the hydrochloric acid treatment of immersing in 12N hydrochloric acid at 25° C. for 10 minutes was not performed. An evaluation substrate was produced in the same manner as in Example 1 except for the above matters.

<Comparative Example 2>
In Example 2, the hydrochloric acid treatment of immersing in 12N hydrochloric acid at 25° C. for 10 minutes was not performed. An evaluation substrate was produced in the same manner as in Example 2 except for the above matters.

<Reference example 1>
In Example 1, 150 parts by mass of magnetic powder (“M05S”, Fe—Mn ferrite, average particle size 3 μm, manufactured by Powdertech) was replaced with 60 parts by mass of silica (“SC2050” manufactured by Admatechs). , 12 N hydrochloric acid at 25° C. for 10 minutes without hydrochloric acid treatment. An evaluation substrate was produced in the same manner as in Example 1 except for the above matters.

<Evaluation of insoluble matter amount in electroless plating process>
The evaluation substrates (5 cm square) prepared in Examples 1 and 2, Comparative Examples 1 and 2, and Reference Example 1 were treated with a reducing solution ("Reducer Accelerator 810 mod.", manufactured by Atotech Japan, 60 ml, "Reducer Neogant WA ”, Atotech Japan Co., Ltd., 3 ml) at 40° C. for 24 hours. Precipitates deposited in the bath are filtered as insolubles using filter paper (No. 5B 60φ manufactured by Kiriyama Seisakusho Co., Ltd.), vacuum dried for 5 hours, and then the amount of insolubles is measured using a precision balance. was evaluated according to the criteria of
○: The amount of insoluble matter is less than 300 mg ×: The amount of insoluble matter is 300 mg or more

<Evaluation of copper plating peel strength>
The evaluation substrates prepared in Examples 1 and 2, Comparative Examples 1 and 2, and Reference Example 1 were placed in a mixture of a solution containing PdCl ₂ (“Activator Neogant 834” manufactured by Atotech Japan) and sodium hydroxide at 40°C. for 5 minutes, then immersed in a reducing solution (a mixture of "Reducer Neogant WA" and "Reducer Accelerator 810 mod." manufactured by Atotech Japan) at 30 ° C. for 5 minutes, and then the electroless copper plating solution. (“Sulcup 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, copper sulfate electrolytic plating solution (mixture of "Additive Cupraside HL" manufactured by Atotech Japan, copper sulfate pentahydrate, and sulfuric acid) at 22 ° C. After immersion for 60 minutes, a conductor layer with a thickness of 30 μm was formed on the magnetic layer. Annealing was then performed at 180° C. for 60 minutes. This substrate was used as a peel strength evaluation substrate.

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

From Examples 1 and 2, it was found that the amount of insoluble matter in the substrate obtained by performing the step (A) of the present invention can be greatly suppressed. On the other hand, in Comparative Examples 1 and 2 in which the step (A) was not performed, a large amount of insoluble matter was deposited. In addition, since the results of Examples 1 and 2 did not deviate greatly from the amount of insoluble matter in Reference Example 1, it was found that precipitation of insoluble matter derived from the magnetic powder was greatly suppressed.
It was also confirmed that there was no significant difference in the results of copper plating peel strength even after the step (A) was performed, and no deterioration in physical properties occurred.

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

The paste 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. After that, the surface of the paste layer was buffed. Further, the paste layer was thermally 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), heat-treated by heating at 180° C. for 30 minutes, and then immersed in 12N hydrochloric acid at 25° C. for 10 minutes.

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

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

In the catalyst activation step, the magnetic layer was immersed in a reducing solution (Reducer Neogand WA: 5 ml/L, Reducer Accelerator 810 mod: 100 ml/L) manufactured by Atotech Japan at 30° C. for 5 minutes.

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

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

REFERENCE SIGNS LIST 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 second Main surface 220 through hole 220a through hole wiring 240 external terminal 300 magnetic part 310 magnetic sheet 320a resin composition layer 320 first magnetic layer 330 support 340 second magnetic layer 360 via hole 360a via hole wiring 400 coil-shaped conductive structure 420 First conductor layer 420a Land 440 Second conductor layer

Claims (19)

A method for manufacturing a substrate in which a conductor layer is formed by wet plating on a magnetic layer containing magnetic powder,
(A) an acid treatment step of treating the surface of the magnetic layer with an acid solution; and (B) a step of forming a conductor layer on the magnetic layer whose surface has been treated with the acid solution,
(A) A method for manufacturing a substrate, wherein the concentration of the acid solution in the step is 3N or higher . 2. The method according to claim 1, wherein the step (B) performs electroless plating to form a conductor layer. 3. The method according to claim 1 or 2 , wherein the concentration of the acid solution in step (A) is 3N or more and 40N or less. The method according to any one of claims 1 to 3 , wherein the acid solution in step (A) comprises an inorganic acid. 5. The method according to any one of claims 1 to 4 , wherein the acid solution in step (A) is at least one selected from hydrochloric acid, sulfuric acid and nitric acid. The method according to any one of claims 1 to 5 , wherein the acid solution in step (A) is hydrochloric acid. (A) After the process (B) Before the process,
(3) The method according to any one of claims 1 to 6 , further comprising a conditioning step of treating the surface of the magnetic layer with a solution containing a surfactant. (3) After the process (B) Before the process,
8. The method according to claim 7 , further comprising (4) a catalyzing step of applying a catalyst to the surface of the magnetic layer, and (5) a catalyst activating step of activating the catalyst, in this order. 9. The method according to any one of claims 1 to 8 , wherein in the step (B), electroless plating is performed and then electroplating is performed to form a conductor layer. (A) before the step,
10. The method according to any one of claims 1 to 9 , further comprising the step of (1) filling the through holes with a pasty resin composition and curing the resin composition to form a magnetic layer. (1) After the process (A) Before the process,
11. The method of claim 10 , further comprising (2) polishing the surface of the magnetic layer. The method according to any one of claims 1 to 11 , wherein the substrate is an inductor substrate having inductor elements formed by patterned conductor layers. 13. The method according to any one of claims 1 to 12 , wherein the magnetic layer is formed by curing a resin composition containing magnetic powder and a binder resin. 14. The method of claim 13 , wherein the binder resin comprises a thermosetting resin. 15. The method of claim 14 , wherein the thermosetting resin is an epoxy resin. The method according to any one of claims 10 to 15 , wherein the content of the magnetic powder is 70% by mass or more and 98% by mass or less when the non-volatile component in the resin composition is 100% by mass. The method according to any one of claims 1 to 16 , wherein the magnetic powder is at least one selected from iron oxide powder and iron alloy metal powder. The method according to any one of claims 1 to 17 , 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. . The method according to any one of claims 1 to 18 , wherein the magnetic powder comprises iron alloy metal powder containing at least one selected from Si, Cr, Al, Ni, and Co.

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