JP7031206B2 - Resin composition - Google Patents

Description

The present invention relates to a resin composition containing a magnetic filler. Further, the present invention relates to a resin sheet and an inductor component obtained by using the resin composition.

In recent years, electronic devices have become smaller and more sophisticated, and there is an increasing demand for smaller and thinner inductor components (coils) mounted on printed wiring boards as well as printed wiring boards. For this reason, there is a demand for thinner base materials (core materials) used for inductor parts, and further, inductor parts having a coreless structure (see, for example, Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2016-134424

When manufacturing a thin inductor component or an inductor component having a coreless structure, when the magnetic layer (insulating layer) is formed by a resin composition containing a magnetic filler, the inductor component is warped due to the curing shrinkage of the magnetic layer itself. The problem of being easy to do arises. When warpage occurs, the reliability of mounting is impaired when the inductor component is mounted on the printed wiring board.

On the other hand, in order to suppress warpage, it is conceivable to add a component that enhances the flexibility of the cured resin product (magnetic layer). However, in order to fully exert the warp prevention effect, it is necessary to add a considerable amount of a component that enhances flexibility, so that the content of the magnetic filler is relatively low, which is disadvantageous for increasing the magnetic permeability of the magnetic layer. Therefore, the performance of the inductor components tends to deteriorate.

Therefore, the subject of the present invention is a resin composition for forming a magnetic layer of an inductor component, which can suppress the occurrence of warpage even when the inductor component is made thinner while maintaining a high magnetic permeability of the inductor component; It is an object of the present invention to provide a resin sheet; a wiring board with a built-in inductor element; and a printed wiring board, which are obtained by using the resin sheet.

As a result of diligent studies to solve the above problems, the present inventors have found that a resin composition containing an epoxy resin, a magnetic filler, a curing agent, and an amphoteric polyether block copolymer forms a magnetic layer. We have found that the maintenance of magnetic permeability and the suppression of warpage can be achieved at the same time, and have completed the present invention.

That is, the present invention includes the following contents.
[1] (A) Epoxy resin,
(B) Magnetic filler,
A resin composition containing (C) a curing agent and (D) an amphipathic polyether block copolymer.
[2] The resin composition according to [1], wherein the content of the component (B) is 75% by mass or more and less than 95% by mass when the non-volatile component in the resin composition is 100% by mass.
[3] The content of the component (D) is 0.3% by mass or more and 15% by mass or less when the non-volatile component in the resin composition is 100% by mass, according to [1] or [2]. Resin composition.
[4] The component (D) is a block copolymer containing at least one epoxy resin miscible polyether block segment and at least one epoxy resin immiscible polyether block segment, according to [1] to [3]. The resin composition according to any one.
[5] Epoxy resin miscible polyether block segments are selected from polyethylene oxide blocks, polypropylene oxide blocks, poly (ethylene oxide-co-propylene oxide) blocks, poly (ethylene oxide-ran-propylene oxide) blocks, and mixtures thereof. One or more polyalkylene oxide blocks
Epoxy resin immiscible polyether block segments are one or more polyalkylene oxide blocks selected from polybutylene oxide blocks, polyhexylene oxide blocks, polydodecylene oxide blocks, and mixtures thereof, [4. ] The resin composition according to.
[6] The resin composition according to any one of [1] to [5], further containing (E) a carbodiimide compound.
[7] The resin composition according to any one of [1] to [6], further containing (F) a thermoplastic resin.
[8] The resin composition according to any one of [1] to [7], wherein the component (C) is at least one selected from a triazine skeleton-containing phenol-based curing agent and an active ester-based curing agent.
[9] The resin composition according to any one of [1] to [8], wherein the component (A) contains an epoxy resin having a condensed ring structure.
[10] Any of [1] to [9], wherein the cured product obtained by thermally curing the resin composition at 100 ° C. for 30 minutes and further at 190 ° C. for 60 minutes has a curing shrinkage rate of 0.27% or less. The resin composition described.
[11] Any of [1] to [10], wherein the cured product obtained by thermally curing the resin composition at 190 ° C. for 90 minutes has a linear thermal expansion coefficient of 3 ppm / ° C. or higher and 30 ppm / ° C. or lower at 30 ° C. to 150 ° C. The resin composition described in Crab.
[12] The resin composition according to any one of [1] to [11], which is used for forming a magnetic layer of a wiring board including an inductor element.
[13] A resin sheet comprising a support and a resin composition layer provided on the support and formed of the resin composition according to any one of [1] to [12].
[14] It has a magnetic layer which is a cured product of the resin composition layer of the resin sheet according to [13], and a conductive structure in which at least a part thereof is embedded in the magnetic layer.
A wiring board with a built-in inductor element, which includes an inductor element formed of the conductive structure and a part of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. ..
[15] A printed wiring board including the wiring board with a built-in inductor element according to [14] as an inner layer board.

According to the present invention, a resin composition for forming a magnetic layer of an inductor component, which can suppress the occurrence of warpage even when the inductor component is made thinner while maintaining a high magnetic permeability of the inductor component; the resin composition is used. A resin sheet; a wiring board with a built-in inductor element; and a printed wiring board can be provided.

FIG. 1 is a schematic plan view of the inductor element built-in wiring board of the first embodiment as an example, as viewed from one side in the thickness direction. FIG. 2 is a schematic view showing a cut end surface of the wiring board with a built-in inductor element of the first embodiment cut at the position indicated by the II-II alternate long and short dash line as an example. FIG. 3 is a schematic plan view for explaining the configuration of the first wiring layer in the inductor element built-in wiring board of the first embodiment as an example. FIG. 4 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 5 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 6 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 7 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 8 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 9 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 10 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 11 is a schematic cross-sectional view for explaining a method of manufacturing a wiring board with a built-in inductor element according to a second embodiment as an example. FIG. 12 is a schematic view showing an example of a resin sheet for measuring the curing shrinkage rate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing merely shows the shape, size and arrangement of the components schematically to the extent that the invention can be understood. The present invention is not limited to the following description, and each component can be appropriately modified without departing from the gist of the present invention. In the drawings used in the following description, similar components may be designated with the same reference numerals, and duplicate description may be omitted. Further, the configuration according to the embodiment of the present invention is not always manufactured or used by the arrangement of the illustrated examples.

[Resin composition]
The resin composition of the present invention contains (A) an epoxy resin, (B) a magnetic filler, (C) a curing agent, and (D) an amphipathic polyether block copolymer.

By incorporating the component (A), the component (B), the component (C), and the component (D) into the resin composition, it is possible to obtain a magnetic layer capable of suppressing warpage. The resin composition may further contain (E) a carbodiimide compound, (F) a curing accelerator, (G) a thermoplastic resin, and (H) other additives, if necessary.

<(A) Epoxy resin>
The resin composition contains (A) an epoxy resin. Examples of the epoxy resin include naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, and naphthalene type. Epoxy resin having a fused ring structure such as tetrafunctional epoxy resin, naphthol type epoxy resin, naphthylene ether type epoxy resin, dicyclopentadiene type epoxy resin; bisphenol A type epoxy resin; bisphenol F type epoxy resin; bisphenol S type epoxy resin Bisphenol AF type epoxy resin; Trisphenol type epoxy resin; Novorak type epoxy resin; Naftor Novolak type epoxy resin; Phenol novolak type epoxy resin; tert-butyl-catechol type epoxy resin; Glycidylamine type epoxy resin; Cresol novolak type epoxy resin; Biphenyl type epoxy resin; Linear aliphatic epoxy resin; Epoxy resin having a butadiene structure; Oil ring type epoxy resin; Heterocyclic epoxy resin; Spiro ring-containing epoxy resin; Cyclohexanedimethanol type epoxy resin ; Trimethylol type epoxy resin; Tetraphenyl ethane type epoxy resin; Bixirenol type epoxy resin and the like can be mentioned. The epoxy resin may be used alone or in combination of two or more.

The epoxy resin (A) is preferably one or more selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolac type epoxy resin and epoxy resin having a fused ring structure. Above all, as the component (A), it is more preferable to contain an epoxy resin having a condensed ring structure from the viewpoint of obtaining a magnetic layer having excellent physical properties such as an average linear thermal expansion coefficient. Examples of the epoxy resin having a fused ring structure include naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, and dicyclopentadiene type epoxy. Resins are preferable, and naphthalene type epoxy resins and naphthol type epoxy resins are particularly preferable.

The epoxy resin (A) preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the non-volatile component of the epoxy resin is 100% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Among them, the resin composition is a combination of a liquid epoxy resin at a temperature of 20 ° C. (hereinafter referred to as “liquid epoxy resin”) and a solid epoxy resin at a temperature of 20 ° C. (hereinafter referred to as “solid epoxy resin”). It is preferable to include it. By using a liquid epoxy resin and a solid epoxy resin in combination as the epoxy resin, a resin composition having excellent flexibility can be obtained. In addition, the breaking strength of the cured product of the resin composition is also improved. The liquid epoxy resin is preferably a liquid epoxy resin having two or more epoxy groups in one molecule. The solid epoxy resin is preferably a solid epoxy resin having three or more epoxy groups in one molecule.

Examples of the liquid epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, and ester skeleton. An alicyclic epoxy resin, a cyclohexanedimethanol type epoxy resin, a glycidylamine type epoxy resin, and an epoxy resin having a butadiene structure are preferable, and a glycidylamine type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol AF are preferable. Type epoxy resin and naphthalene type epoxy resin are more preferable. Specific examples of the liquid epoxy resin include "HP4032", "HP4032D" and "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC, and "828US" and "jER828EL" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd. , "JER807" (bisphenol F type epoxy resin), "jER152" (phenol novolak type epoxy resin), "630", "630LSD" (glycidylamine type epoxy resin), "ZX1059" (bisphenol A) manufactured by Nippon Steel & Sumitomo Metal Corporation. (Mixed product of type epoxy resin and bisphenol F type epoxy resin), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase Chemtex Co., Ltd., "Selokiside 2021P" (alicyclic epoxy having an ester skeleton) manufactured by Daicel Co., Ltd. Resin), "PB-3600" (epoxy resin having a butadiene structure), "ZX1658", "ZX1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel & Sumitomo Metal Corporation, "630LSD" (glycidyl) manufactured by Mitsubishi Chemical Co., Ltd. (Amine type epoxy resin), "EP-3980S" (glycidylamine type epoxy resin) manufactured by ADEKA, and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the solid epoxy resin include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, and naphthylene ether type epoxy resin. Anthracene type epoxy resin, bisphenol A type epoxy resin, and tetraphenylethane type epoxy resin are preferable, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin, and biphenyl type epoxy resin are more preferable. Specific examples of the solid epoxy resin include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalen type tetrafunctional epoxy resin), and "N-690" manufactured by DIC. Cresol novolak type epoxy resin), "N-695", "N-680" (cresol novolak type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "HP-7200HH", "HP-7200H" , "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin), manufactured by Nippon Kayakusha. "EPPN-502H" (trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), Nippon Steel & Sumitomo Metal Corporation "ESN475V" (naphthalen type epoxy resin), "ESN485" (naphthol novolac type epoxy resin), "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixilenol type epoxy) manufactured by Mitsubishi Chemical Co., Ltd. Resin), "YX8800" (anthracene type epoxy resin), "PG-100", "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd., "YL7800" (Fluorene type epoxy resin), "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd., "jER1031S" (tetraphenylethane type epoxy resin), "157S70" (novolak type epoxy resin) and the like can be mentioned. .. These may be used alone or in combination of two or more.

(A) When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, their quantitative ratios (liquid epoxy resin: solid epoxy resin) are 1: 0.1 to 1:15 in terms of mass ratio. The range of is preferable. By setting the amount ratio of the liquid epoxy resin to the solid epoxy resin within such a range, i) when used in the form of a resin sheet, appropriate adhesiveness is obtained, and ii) when used in the form of a resin sheet. Sufficient flexibility can be obtained, handleability is improved, and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects of i) to iii) above, the quantitative ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.3 to 1:10 in terms of mass ratio. Is more preferable, and the range of 1: 0.5 to 1: 8 is even more preferable.

The content of the epoxy resin (A) is preferably 1% by mass or more when the non-volatile component in the resin composition is 100% by mass from the viewpoint of obtaining a magnetic layer exhibiting good mechanical strength and insulation reliability. It is preferably 2% by mass or more, more preferably 3% by mass or more. The upper limit of the content of the epoxy resin (A) is not particularly limited as long as the effect of the present invention is exhibited, but is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less. be.

The epoxy equivalent of the epoxy resin (A) is preferably 50 to 5000, more preferably 50 to 3000, still more preferably 80 to 2000, and even more preferably 110 to 1000. Within this range, the crosslink density of the cured product becomes sufficient, and a magnetic layer having a small surface roughness can be obtained. The epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of the epoxy group.

The weight average molecular weight of the epoxy resin (A) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method.

The number average molecular weight of the epoxy resin (A) is preferably less than 5,000, more preferably 4,000 or less, and even more preferably 3,000 or less. The lower limit is preferably 100 or more, more preferably 300 or more, and even more preferably 500 or more. The number average molecular weight (Mn) is a polystyrene-equivalent number average molecular weight measured using GPC (gel permeation chromatography).

(A) The glass transition temperature (Tg) of the epoxy resin is preferably more than 25 ° C, more preferably 30 ° C or higher, still more preferably 35 ° C or higher. The upper limit is preferably 500 ° C. or lower, more preferably 400 ° C. or lower, still more preferably 300 ° C. or lower.

<(B) Magnetic filler>
The resin composition contains (B) a magnetic filler. The material of the magnetic filler (B) is not particularly limited, and is, for example, pure iron powder, Fe—Si alloy powder, Fe—Si—Al alloy powder, Fe—Cr alloy powder, Fe—Cr—Si alloy powder. , Fe—Ni—Cr alloy powder, Fe—Cr—Al alloy powder, Fe—Ni alloy powder, Fe—Ni—Mo alloy powder, Fe—Ni—Mo—Cu alloy powder, Fe—Co series Alloy powder, Fe alloys such as Fe—Ni—Co alloy powder, amorphous alloys such as Fe-based amorphous and Co-based amorphous, Mg—Zn-based ferrite, Mn—Zn-based ferrite, Mn—Mg-based ferrite, Cu Spinel-type ferrites such as -Zn-based ferrite, Mg-Mn-Sr-based ferrite, Ni-Zn-based ferrite, Ba-Zn-based ferrite, Ba-Mg-based ferrite, Ba-Ni-based ferrite, Ba-Co-based ferrite, Ba -Examples include hexagonal ferrites such as Ni—Co-based ferrite and garnet-type ferrites such as Y-based ferrite. Among them, as the (B) magnetic filler, Fe—Si alloy powder, Fe—Si—Al alloy powder, Fe—Cr alloy powder, Fe—Cr—Si alloy powder, Fe—Ni—Cr alloy powder Fe alloys containing one or more elements selected from Si, Al, and Cr, such as Fe—Cr—Al alloy powder, are preferable, and Fe alloys containing Si and Cr are more preferable. (B) The magnetic filler may be used alone or in combination of two or more.

(B) As the magnetic filler, a commercially available magnetic filler can be used. Specific examples of commercially available magnetic fillers that can be used include "PST-S" manufactured by Sanyo Special Steel Co., Ltd., "AW2-08", "AW2-08PF20F" manufactured by Epson Atmix Co., Ltd., "AW2-08PF10F", and "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", Toda Kogyo Co., Ltd. "KNS-415", "BSF-547", "BSF-" 029 "," BSN-125 "," BSN-714 "," BSN-828 "," S-1281 "," S-1641 "," S-1651 "," S-1470 "," S-1511 " , "S-2430", "JR09P2" manufactured by Nippon Heavy Chemical Industries, Ltd., "Nanotek" manufactured by CIK Nanotech, "JEMK-S", "JEMK-H" manufactured by Kinsei Matech, "Ytrium iron oxide" manufactured by ALDRICH, etc. Can be mentioned.

(B) The magnetic filler is preferably spherical. (B) The value (aspect ratio) obtained by dividing the length of the long side of the powder of the magnetic filler by the length of the short side is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.2. It is as follows. In general, it is easier to improve the relative permeability when the magnetic filler has a flat shape that is not spherical. However, from the viewpoint of maintaining the magnetic permeability and suppressing the warp at the same time, it is easier to obtain a resin composition having desired properties by using the spherical (B) magnetic filler.

(B) The average particle size of the magnetic filler is preferably 0.01 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more. Further, it is preferably 8 μm or less, more preferably 5 μm or less, still more preferably 4 μm or less. (B) By setting the average particle size of the magnetic filler within such a range, it is possible to maintain the magnetic permeability and suppress the warp at the same time.

(B) The average particle size of the magnetic filler can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of the magnetic filler on a volume basis using a laser diffraction / scattering type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, a magnetic filler dispersed in methyl ethyl ketone by ultrasonic waves can be preferably used. As the laser diffraction / scattering type particle size distribution measuring device, "LA-500" manufactured by HORIBA, Ltd., "SALD-2200" manufactured by Shimadzu Corporation, or the like can be used.

(B) The content (% by volume) of the magnetic filler is preferably 10% by volume or more, more preferably 20% by volume when the non-volatile component in the resin composition is 100% by volume from the viewpoint of improving the specific magnetic permeability. % Or more, more preferably 30% by volume or more. Further, it is preferably 85% by volume or less, more preferably 75% by volume or less, and further preferably 65% by volume or less.

The content of the magnetic filler (B) is preferably 75% by mass or more, more preferably 76% by mass or more, and further, when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of improving the specific magnetic permeability. It is preferably 77% by mass or more. Further, it is preferably less than 95% by mass, more preferably 94% by mass or less, and further preferably 93% by mass or less.

<(C) Curing agent>
The resin composition contains (C) a curing agent. The (C) curing agent is not particularly limited as long as it has a function of curing the (A) epoxy resin or the like, and for example, a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, a benzoxazine-based curing agent, and the like. And cyanate ester-based curing agents and the like. The curing agent may be used alone or in combination of two or more. The component (C) is preferably one or more selected from a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent, and is preferably a phenol-based curing agent and an active ester-based curing agent. It is preferably one or more selected from the agents, and as one embodiment, it is selected from a triazine skeleton-containing phenolic curing agent and an active ester-based curing agent from the viewpoint of improving characteristics such as peel strength and magnetic permeability. It is more preferable that the number is one or more.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable from the viewpoint of obtaining sufficient strength of the cured product. Further, 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 curing agent is more preferable.

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and "NHN" and "CBN" manufactured by Nippon Kayaku Co., Ltd. , "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495V", "SN375", "SN395" manufactured by Nippon Steel & Sumitomo Metal Corporation, "TD2090" manufactured by DIC Corporation. , "TD2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500" , "KA-1160", "KA-1163", "KA-1165", "GDP-6115L", "GDP-6115H", "ELPC75" manufactured by Gunei Chemical Co., Ltd. and the like.

The active ester-based curing agent is not particularly limited, but generally contains an ester group having high reaction activity such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds in one molecule. A compound having two or more esters is preferably used. The active ester-based curing agent 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 curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester-based curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid and the like. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-. Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenol, trihydroxybenzophenone, tetrahydroxybenzophenone, fluoroglucin, Examples thereof include benzenetriol, dicyclopentadiene-type diphenol compound, and phenol novolac. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two phenol molecules with one dicyclopentadiene molecule.

Specifically, an active ester curing agent containing a dicyclopentadiene type diphenol structure, an active ester curing agent containing a naphthalene structure, an active ester curing agent containing an acetylated product of phenol novolac, and an active ester curing agent containing a benzoylated product of phenol novolac. Agents are preferable, and among them, an active ester curing agent containing a naphthalene structure and an active ester curing agent containing a dicyclopentadiene type diphenol structure are more preferable. The "dicyclopentadiene-type diphenol structure" represents a divalent structure composed of phenylene-dicyclopentylene-phenylene.

Commercially available products of the active ester-based curing agent include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000", "HPC-8000H", as active ester curing agents containing a dicyclopentadiene type diphenol structure. "HPC-8000-65T", "EXB-8000L" (manufactured by DIC), "EXB9416-70BK" (manufactured by DIC) as an active ester curing agent containing a naphthalene structure, an active ester curing agent containing an acetylated product of phenol novolac. "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester curing agent containing a benzoylated product of phenol novolac, and "DC808" (manufactured by Mitsubishi Chemical Co., Ltd.) as an active ester curing agent containing an acetylated product of phenol novolac. Mitsubishi Chemical Co., Ltd.), "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1030" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1048" (manufactured by Mitsubishi Chemical Co., Ltd.), etc. Can be mentioned.

Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa High Polymer Co., Ltd., "Pd" and "FA" manufactured by Shikoku Chemicals Corporation.

Examples of the cyanate ester-based curing agent include bisphenol A dicyanate, polyphenol cyanate, oligo (3-methylene-1,5-phenylencyanate), 4,4'-methylenebis (2,6-dimethylphenylcyanate), and 4,4. '-Etilidendiphenyl disyanate, hexafluorobisphenol A disyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanate phenylmethane), bis (4-cyanate-3,5-dimethyl) Bifunctional cyanate resins such as phenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bis (4-cyanatephenyl) ether, phenol. Examples thereof include polyfunctional cyanate resins derived from novolak and cresol novolak, and prepolymers in which these cyanate resins are partially triazined. Specific examples of the cyanate ester-based curing agent include "PT30" and "PT60" (both are phenol novolac type polyfunctional cyanate ester resins), "BA230", and "BA230S75" (part of bisphenol A dicyanate) manufactured by Lonza Japan. Alternatively, a prepolymer in which the whole is triazined to become a trimer) and the like can be mentioned.

The content of the curing agent (C) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass, when the resin component in the resin composition is 100% by mass. The above is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass or less. (C) By setting the content of the curing agent within such a range, the warp generated when the magnetic layer is formed can be suppressed, and further, the physical properties such as the coefficient of linear thermal expansion and the peel strength are excellent. A magnetic layer can be obtained.

<(D) Amphiphilic polyether block copolymer>
The resin composition contains (D) amphipathic polyether block copolymers. As used herein, the amphoteric polyether block copolymer refers to a block copolymer comprising at least one epoxy resin miscible polyether block segment and at least one epoxy resin immiscible polyether block segment. By containing the component (D), the toughness of the resin composition and the stress relaxation performance can be improved, whereby the amount of warpage of the cured product of the resin composition can be reduced.

Examples of the epoxy resin miscible polyether block segment include an epoxy resin miscible polyether block segment derived from an alkylene oxide. Epoxy resin mixed polyether block segments derived from alkylene oxide include polyethylene oxide blocks, polypropylene oxide blocks, poly (ethylene oxide-co-propylene oxide) blocks, poly (ethylene oxide-ran-propylene oxide) blocks, and theirs. One or more polyalkylene oxide blocks selected from the mixture are preferred, and polyethylene oxide blocks are more preferred.

Epoxy resin immiscible block segments include, for example, at least one epoxy resin immiscible polyether block segment derived from an alkylene oxide. The at least one epoxy resin immiscible polyether block segment derived from alkylene oxide includes, for example, a polybutylene oxide block, a polyhexylene oxide block derived from 1,2-epoxyhexane, 1,2-epoxydodecane. A polydodecylene oxide block derived from, and one or more polyalkylene oxide blocks selected from a mixture thereof are preferred, and a polybutylene oxide block is more preferred.

(D) The amphipathic polyether block copolymer preferably has one or more epoxy resin miscible block segments, and more preferably two or more epoxy resin miscible block segments. Similarly, it is preferable to have one or more types of epoxy resin immiscible block segments, and it is more preferable to have two or more types of epoxy resin immiscible block segments. Therefore, the component (D) is an epoxy selected from the group consisting of, for example, diblock, linear triblock, linear tetrablock, higher-order multi-block structure, branched block structure, star-shaped block structure, and a combination thereof. It is preferable to have a resin miscible block segment or an epoxy resin immiscible block segment.

The amphipathic polyether block copolymer may contain other segments in the molecule as long as the effect is not impaired. Other segments are derived from, for example, polyalkylmethyl methacrylates such as polyethylene propylene (PEP), polybutadiene, polyisoprene, polydimethylsiloxane, polybutylene oxide, polyhexylene oxide, polyethylhexyl methacrylate, and mixtures thereof. Examples include segments.

(D) The number average molecular weight of the amphipathic polyether block copolymer is preferably 3,000 to 20,000. The number average molecular weight is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method.

(D) Examples of the amphoteric polyether block copolymer include poly (ethylene oxide) -b-poly (butylene oxide) (PEO-PBO); poly (ethylene oxide) -b-poly (butylene oxide) -b-poly ( Examples thereof include an amphipathic polyether triblock copolymer such as polyethylene oxide (PEO-PBO-PEO). Commercially available products can also be used as amphipathic block copolymers. Examples of commercially available products include "Fortegra 100" manufactured by The Dow Chemical Company. (D) The amphipathic polyether block copolymer may be used alone or in combination of two or more.

The content of the component (D) is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, from the viewpoint of suppressing the amount of warpage when the non-volatile component in the resin composition is 100% by mass. , More preferably 0.5% by mass or more. The upper limit is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, from the viewpoint of improving characteristics such as peel strength and magnetic permeability.

<(E) Carbodiimide compound>
The resin composition may contain (E) a carbodiimide compound. The (E) carbodiimide compound is a compound having one or more carbodiimide groups (-N = C = N-) in one molecule, and the inclusion of the (E) carbodiimide compound provides magnetism with excellent adhesion to the conductor layer. Can bring layers. As the (E) carbodiimide compound, a compound having two or more carbodiimide groups in one molecule is preferable. (E) The carbodiimide compound may be used alone or in combination of two or more.

In one embodiment, the carbodiimide compound contained in the resin composition of the present invention contains a structure represented by the following formula (1).

（式中、Ｘは、アルキレン基、シクロアルキレン基又はアリーレン基を表し、これらは置換基を有していてもよい。ｐは１～５の整数を表す。Ｘが複数存在する場合、それらは同一でも相異なってもよい。＊は結合手を表す。）

(In the formula, X represents an alkylene group, a cycloalkylene group or an arylene group, which may have a substituent. P represents an integer of 1 to 5. If a plurality of Xs are present, they may have a substituent. It may be the same or different. * Indicates a bond.)

The number of carbon atoms of the alkylene group represented by X is preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 6, 1 to 4, or 1 to 3. The number of carbon atoms does not include the number of carbon atoms of the substituent. Preferable examples of the alkylene group include a methylene group, an ethylene group, a propylene group and a butylene group.

The number of carbon atoms of the cycloalkylene group represented by X is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. The number of carbon atoms does not include the number of carbon atoms of the substituent. Preferable examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.

The arylene group represented by X is a group obtained by removing two hydrogen atoms on an aromatic ring from an aromatic hydrocarbon. The arylene group preferably has 6 to 24 carbon atoms, more preferably 6 to 18, still more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms does not include the number of carbon atoms of the substituent. Preferable examples of the arylene group include a phenylene group, a naphthylene group and an anthrasenylene group.

The alkylene group, cycloalkylene group or aryl group represented by X may have a substituent. The substituent is not particularly limited, and examples thereof include a halogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkyloxy group, an aryl group, an aryloxy group, an acyl group and an acyloxy group. Examples of the halogen atom used as the substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. The alkyl group and the alkoxy group used as the substituent may be linear or branched, and the number of carbon atoms thereof is preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 1. 6, 1 to 4, or 1 to 3. The number of carbon atoms of the cycloalkyl group and the cycloalkyloxy group used as the substituent is preferably 3 to 20, more preferably 3 to 12, still more preferably 3 to 6. The aryl group used as a substituent is a group obtained by removing one hydrogen atom on the aromatic ring from an aromatic hydrocarbon, and the number of carbon atoms thereof is preferably 6 to 24, more preferably 6 to 18, still more preferable. Is 6 to 14, and even more preferably 6 to 10. The aryloxy group used as a substituent preferably has 6 to 24 carbon atoms, more preferably 6 to 18, still more preferably 6 to 14, and even more preferably 6 to 10. The acyl group used as a substituent refers to a group represented by the formula: -C (= O) -R ¹ (in the formula, R ¹ represents an alkyl group or an aryl group). The alkyl group represented by R ¹ may be linear or branched, and the number of carbon atoms thereof is preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 6. 1 to 4 or 1 to 3. The number of carbon atoms of the aryl group represented by R ¹ is preferably 6 to 24, more preferably 6 to 18, still more preferably 6 to 14, and even more preferably 6 to 10. The acyloxy group used as a substituent refers to a group represented by the formula: -OC (= O) -R ¹ (in the formula, R ¹ has the same meaning as described above). Among them, as the substituent, an alkyl group, an alkoxy group, and an acyloxy group are preferable, and an alkyl group is more preferable.

In equation (1), p represents an integer of 1 to 5. From the viewpoint of realizing a magnetic layer having further excellent heat resistance, laser via reliability, and peel strength, p is preferably 1 to 4, more preferably 2 to 4, still more preferably 2 or 3.

When a plurality of Xs exist in the formula (1), they may be the same or different from each other. In one preferred embodiment, at least one X is an alkylene group or a cycloalkylene group, which may have a substituent.

In a preferred embodiment, the carbodiimide compound is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and further preferably 70% by mass or more, when the total mass of the molecule of the carbodiimide compound is 100% by mass. More preferably, it contains a structure represented by the formula (1) in an amount of 80% by mass or more or 90% by mass or more. The carbodiimide compound may substantially be the structure represented by the formula (1) except for the terminal structure. The terminal structure of the carbodiimide compound is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, and an aryl group, which may have a substituent. The alkyl group, cycloalkyl group, and aryl group used as the terminal structure may be the same as the alkyl group, cycloalkyl group, and aryl group described for the substituent which the group represented by X may have. Further, the substituent which may be possessed by the group used as the terminal structure may be the same as the substituent which may be possessed by the group represented by X.

From the viewpoint of suppressing the generation of outgas when the resin composition is cured, the weight average molecular weight of the carbodiimide compound is preferably 500 or more, more preferably 600 or more, still more preferably 700 or more, still more preferably 800 or more. Particularly preferably, it is 900 or more or 1000 or more. Further, from the viewpoint of obtaining good compatibility, the upper limit of the weight average molecular weight of the carbodiimide compound is preferably 5000 or less, more preferably 4500 or less, still more preferably 4000 or less, still more preferably 3500 or less, and particularly preferably 3000 or less. Is. The weight average molecular weight of the carbodiimide compound can be measured by, for example, a gel permeation chromatography (GPC) method (polystyrene equivalent).

The carbodiimide compound may contain an isocyanate group (-N = C = O) in the molecule due to its production method. The content of isocyanate groups (also referred to as "NCO content") in the carbodiimide compound is determined from the viewpoint of obtaining a resin composition exhibiting good storage stability and, by extension, realizing a magnetic layer exhibiting desired characteristics. It is preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, and particularly preferably 1% by mass or less or 0.5% by mass or less.

As the carbodiimide compound, a commercially available product may be used. Examples of commercially available carbodiimide compounds include Carbodilite (registered trademark) V-02B, V-03, V-04K, V-07 and V-09 manufactured by Nisshinbo Chemical Co., Ltd., and Stavaxol (registered trademark) P manufactured by Rheinchemy Co., Ltd. Examples thereof include P400 and Hykazil 510.

When the resin composition contains (E) a carbodiimide compound, the content of the (E) carbodiimide compound obtains a magnetic layer having excellent properties of heat resistance, laser via reliability, and adhesion to a conductor layer. From the viewpoint, when the non-volatile component in the resin composition is 100% by mass, 0.1% by mass or more is preferable, 0.15% by mass or more is more preferable, and 0.2% by mass or more is further preferable. The upper limit of the content of the (E) carbodiimide compound is not particularly limited, but is preferably 1.5% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less.

<(F) Thermoplastic resin>
The resin composition may contain (F) a thermoplastic resin. Examples of the thermoplastic resin (F) include phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, siloxane resin, poly (meth) acrylic resin, polyalkylene resin, polyalkyleneoxy resin, polyisoprene resin, and polyisobutylene resin. , Polygonide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyether ether ketone resin, polyester resin. The poly (meth) acrylic resin refers to a polyacrylic resin and a polymethacrylic resin.

The polystyrene-equivalent weight average molecular weight of the phenoxy resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and even more preferably in the range of 20,000 to 60,000. The polystyrene-equivalent weight average molecular weight of the phenoxy resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight average molecular weight of the phenoxy resin is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device and Shodex K-800P / K-804L / K-804L manufactured by Showa Denko Corporation as a column. Can be calculated by measuring the column temperature at 40 ° C. using chloroform or the like as a mobile phase and using a standard polystyrene calibration curve.

Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A structure-containing phenoxy resin), "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" (bisphenol acetophenone) manufactured by Mitsubishi Chemical Corporation. Structure-containing phenoxy resin), and also "FX280" and "FX293" manufactured by Nippon Steel & Sumitomo Metal Corporation, "YX7180", "YX6954", "YX7553", "YX7553BH30", "YL7553BH30" manufactured by Mitsubishi Chemical Co., Ltd. , "YL7769", "YL6794", "YL7213", "YL7290", "YL7891", "YL7482" and the like. Of these, a phenoxy resin having a polyalkyleneoxy structure is preferable, and specific examples thereof include "YX-7180" and "YL7553BH30" manufactured by Mitsubishi Chemical Corporation.

The component (F) is one selected from a polybutadiene structure, a polysiloxane structure, a poly (meth) acrylate structure, a polyalkylene structure, a polyalkyleneoxy structure, a polyisoprene structure, a polyisobutylene structure, and a polycarbonate structure in the molecule. It is preferable to have the above structure, and it is preferable to have one or more structures selected from a polybutadiene structure, a poly (meth) acrylate structure, a polyalkyleneoxy structure, a polyisoprene structure, a polyisobutylene structure, and a polycarbonate structure. Is more preferable, and it is further preferable to have one or more structures selected from a polybutadiene structure and a polyalkylene oxy structure. By containing the resin having the above structure, the magnetic layer becomes low elasticity, becomes excellent in shear strength, breaking bending strain, and crackability, and further suppresses the occurrence of warpage. In addition, "(meth) acrylate" refers to methacrylate and acrylate. These structures may be contained in the main chain or the side chain.
The polybutadiene structure may be partially or completely hydrogenated.
As the polyalkylene oxy structure, a polyalkylene oxy structure having 2 to 15 carbon atoms is preferable, a polyalkylene oxy structure having 3 to 10 carbon atoms is more preferable, and a polyalkylene oxy structure having 5 to 6 carbon atoms is further preferable.

The component (F) is preferably in a high molecular weight in order to reduce the warp when the resin composition is cured. The number average molecular weight (Mn) is preferably 1,000 or more, more preferably 1500 or more, still more preferably 3000 or more and 5000 or more. The upper limit is preferably 1,000,000 or less, more preferably 900,000 or less. The number average molecular weight (Mn) is a polystyrene-equivalent number average molecular weight measured using GPC (gel permeation chromatography).

The component (F) preferably has a functional group capable of reacting with the component (A) from the viewpoint of improving the mechanical strength of the cured product. The functional group that can react with the component (A) includes a functional group that appears by heating.

In one preferred embodiment, the functional group capable of reacting with the component (A) is selected from the group consisting of a hydroxy group, a carboxy group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group and a urethane group. It is a functional group that is more than a species. Among them, as the functional group, a hydroxy group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group and a urethane group are preferable, a hydroxy group, an acid anhydride group, a phenolic hydroxyl group and an epoxy group are more preferable, and phenol. Sexual hydroxyl groups are particularly preferred. However, when an epoxy group is contained as a functional group, the number average molecular weight (Mn) is preferably 5,000 or more.

Specific examples of the polybutadiene resin include "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", "Ricon 131MA20", and "Ricon" manufactured by Clay Valley. 184MA6 "(polybutadiene containing acid anhydride group)," GQ-1000 "(hydroxyl-terminated, carboxyl group-introduced polybutadiene)," G-1000 "," G-2000 "," G-3000 "(both ends) manufactured by Nippon Soda. Hydroxyl-terminated polybutadiene), "GI-1000", "GI-2000", "GI-3000" (hydroxyl-terminated polybutadiene with both ends), "FCA-061L" (hydroxyl-terminated polybutadiene skeleton epoxy resin) manufactured by Nagase ChemteX, etc. Can be mentioned. As one embodiment, linear polyimide using hydroxyl group-terminated polybutadiene, diisocyanate compound, and tetrabasic acid anhydride as raw materials (polyimide described in JP-A-2006-37083, International Publication No. 2008/153208) and the like can be mentioned. .. The content of the butadiene structure of the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. For the details of the polyimide resin, the description of JP-A-2006-37083 and International Publication No. 2008/153208 can be referred to, and the contents thereof are incorporated in the present specification.

As poly (meth) acrylic resin, Teisan resin manufactured by Nagase ChemteX, "ME-2000", "W-116.3", "W-197C", "KG-25", "KG-25" manufactured by Negami Kogyo Co., Ltd. KG-3000 ”and the like.
Examples of the polycarbonate resin include "T6002" and "T6001" (polycarbonate diol) manufactured by Asahi Kasei Chemicals, "C-1090", "C-2090" and "C-3090" (polycarbonate diol) manufactured by Kuraray. Be done. Further, a linear polyimide made from a hydroxyl group-terminated polycarbonate, a diisocyanate compound and a tetrabasic acid anhydride can also be used. The content of the carbonate structure of the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. The details of the polyimide resin can be referred to in International Publication No. 2016/129541, and the contents thereof are incorporated in the present specification.

Further, as another specific example, "SMP-2006", "SMP-2003PGMEA", "SMP-5005PGMEA" manufactured by Shinetsu Silicone Co., Ltd., an amine group-terminated polysiloxane, and a linear polyimide made from tetrabasic acid anhydride as raw materials ( International Publication No. 2010/053185, JP-A-2002-12667, JP-A-2000-31386, etc.), "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers, and "KL" manufactured by Kuraray. -610 "," KL613 ", Kaneka's" SIBSTAR-073T "(styrene-isobutylene-styrenepolyimide copolymer)," SIBSTAR-042D "(styrene-isobutyrene block copolymer), Electrochemical Industry Co., Ltd. "Electrified Butyral 4000-2", "Electrified Butyral 5000-A", "Electrified Butyral 6000-C", "Electrified Butyral 6000-EP", Sekisui Chemical Co., Ltd. Eslek BH series, BX series (for example, BX- 5Z), KS series (eg KS-1), BL series, BM series, "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nihon Rika, "Vilomax HR11NN" and "Vilomax HR16NN" manufactured by Toyo Spinning Co., Ltd., Examples thereof include "KS9100" and "KS9300" manufactured by Hitachi Chemical Co., Ltd., "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., polysulfones "P1700" and "P3500" manufactured by Solvay Advanced Polymers, and "AC3832" manufactured by Ganz Kasei Co., Ltd.

When the resin composition contains the component (F), the content of the component (F) is preferably 0.1% by mass when the non-volatile component in the resin composition is 100% by mass from the viewpoint of imparting flexibility. % Or more, more preferably 0.15% by mass or more, still more preferably 0.2% by mass or more, preferably 1.5% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass. It is as follows. By setting the content of the component (F) within such a range, the magnetic permeability of the cured product can be maintained and warpage can be suppressed.

<(G) Curing accelerator>
The resin composition may contain (G) a curing accelerator. Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like, and phosphorus-based curing accelerators and amine-based curing agents. Curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are preferable, and amine-based curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are more preferable. The curing accelerator may be used alone or in combination of two or more.

Examples of the phosphorus-based curing accelerator include triphenylphosphine, phosphonium borate compound, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, and (4-methylphenyl) triphenylphosphonium thiocyanate. , Tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, and triphenylphosphine and tetrabutylphosphonium decanoate are preferable.

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

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, and the like. 2-Ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-Cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-Phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecyl Imidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4- Diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline Examples thereof include imidazole compounds such as 2-phenylimidazolin and adducts of the imidazole compound and an epoxy resin, and 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferable.

As the imidazole-based curing accelerator, a commercially available product may be used, and examples thereof include "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, and trimethylguanidine. Tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo [4.4.0] deca-5-ene, 7-methyl-1,5,7-triazabicyclo [4.4.0] Deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylviguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 -Allylbiguanide, 1-phenylbiguanide, 1- (o-tolyl) biguanide and the like can be mentioned, with dicyandiamide and 1,5,7-triazabicyclo [4.4.0] deca-5-ene being preferred.

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

When the resin composition contains the component (G), the content of the component (G) is preferably 0.001% by mass or more, more preferably 0 when the non-volatile component in the resin composition is 100% by mass. It is .005% by mass or more, more preferably 0.01% by mass or more, preferably 0.1% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.5% by mass or less. By setting the content of the component (G) within such a range, the magnetic permeability of the cured product can be maintained and warpage can be suppressed.

<(H) Arbitrary additive>
The resin composition may further contain other additives, if necessary, and such other additives include, for example, an organic flame retardant, an organic copper compound, an organic zinc compound, an organic cobalt compound, and the like. Examples thereof include metal compounds, binders, thickeners, defoaming agents, leveling agents, adhesion-imparting agents, resin additives such as colorants, and the like.

Examples of the flame retardant include phosphazene compounds, organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, metal hydroxides and the like. Specific examples of the phosphazene compound include, for example, "SPH-100", "SPS-100", "SPB-100", "SPE-100" manufactured by Otsuka Chemical Co., Ltd., and "FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd. , "FP-110", "FP-300", "FP-400" and the like, and as a flame retardant other than the phosphazene compound, a commercially available product may be used, for example, "HCA-HQ" manufactured by Sanko Co., Ltd. , "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd. and the like.

<Physical characteristics of resin composition>
A cured product obtained by thermally curing the resin composition of the present invention at 100 ° C. for 30 minutes and further at 190 ° C. for 60 minutes exhibits a characteristic of low curing shrinkage rate. That is, the curing shrinkage is suppressed, thereby providing a magnetic layer capable of suppressing warpage. The curing shrinkage rate is preferably 0.27% or less, more preferably 0.25% or less, still more preferably 0.2% or less. The lower limit of the curing shrinkage rate is not particularly limited, but may be 0.01% or more. The curing shrinkage rate can be measured according to the method described in Examples described later.

The cured product obtained by thermally curing the resin composition of the present invention at 190 ° C. for 90 minutes exhibits a property of suppressing warpage. Specifically, when the cured product is placed on a smooth table with the surface on the side where the central portion becomes the convex portion facing downward, the absolute value of the distance between the table and the cured product is less than 20 mm. It is preferably less than 15 mm. The warpage can be evaluated according to the method described in Examples described later.

The cured product obtained by thermally curing the resin composition of the present invention at 130 ° C. for 30 minutes and further at 190 ° C. for 60 minutes exhibits a characteristic of being excellent in peel strength with a metal layer, particularly a plated conductor layer formed by plating. That is, it provides a magnetic layer having excellent peel strength. The peel strength is preferably 0.5 kgf / cm or more, more preferably 0.6 kgf / cm or more, and further preferably 0.7 kgf / cm or more. On the other hand, the upper limit of the peel strength is not particularly limited, but may be 1.5 kgf / cm or less. The evaluation of peel strength can be measured according to the method described in Examples described later.

The cured product obtained by thermally curing the resin composition of the present invention at 190 ° C. for 90 minutes exhibits a characteristic that the average linear thermal expansion coefficient (thermal expansion coefficient) is low. That is, it provides a magnetic layer having a low thermal expansion rate. The upper limit of the average coefficient of linear thermal expansion from 30 ° C. to 150 ° C. is preferably 30 ppm / ° C. or lower, more preferably 25 ppm / ° C. or lower, further preferably 20 ppm / ° C. or lower, even more preferably 15 ppm / ° C. or lower, and 10 ppm / ° C. The following are particularly preferred. On the other hand, the lower limit of the coefficient of linear thermal expansion is not particularly limited, and may be 3 ppm / ° C. or higher, 4 ppm / ° C. or higher, 5 ppm / ° C. or higher, or the like. The thermal expansion rate can be measured according to the method described in Examples described later.

The cured product obtained by thermally curing the resin composition at 190 ° C. for 90 minutes exhibits a characteristic of high relative magnetic permeability at a frequency of 100 MHz. The relative magnetic permeability at a frequency of 100 MHz is preferably 5 or more, more preferably 7 or more, still more preferably 9 or more. Further, it is preferably 20 or less, more preferably 18 or less, and further preferably 15 or less. The relative magnetic permeability can be measured according to the method described in Examples described later.

The cured product obtained by thermally curing the resin composition at 190 ° C. for 90 minutes exhibits a characteristic that the loss coefficient at a frequency of 100 MHz is low. The loss coefficient at a frequency of 100 MHz is preferably 0.07 or less, more preferably 0.06 or less, still more preferably 0.05 or less. The lower limit is not particularly limited, but may be 0.0001 or more. The loss factor can be measured according to the method described in Examples described later.

The resin composition of the present embodiment is excellent in fluidity when forming a magnetic layer, and is excellent in sealing property of a wiring layer when it is used as a magnetic layer (cured product). Further, the magnetic layer (cured product) obtained by thermally curing the resin composition of the present embodiment is also excellent in insulating properties.

Therefore, the resin composition of the present embodiment is a wiring board provided with a so-called film-structured inductor element in which a coil is formed within the thickness of a magnetic layer (a magnetic material portion in which a plurality of magnetic layers are laminated). It can be suitably used as a material for a magnetic layer.

[Resin sheet]
The resin sheet of the present invention includes a support and a resin composition layer provided on the support and formed of the resin composition of the present invention.

From the viewpoint of thinning, the thickness of the resin composition layer is preferably 250 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 40 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but may be usually 5 μm or more, 10 μm or more, 20 μm or more, and the like.

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 a support, the plastic material may be, for example, polyethylene terephthalate (hereinafter abbreviated as "PET") or polyethylene naphthalate (hereinafter abbreviated as "PEN"). ) And other polyesters, polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethylmethacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyethersulfide (PES), polyethers. Examples thereof include ketones and polyimides. Of these, 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, aluminum foil, and the like, and copper foil is preferable. 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 another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. You may use it.

The support may be matted or corona-treated on the surface to be joined to the resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be joined to the resin composition layer may be used. Examples of the release agent used for the release layer of the support with the release layer include one or more release agents selected from the group consisting of alkyd resin, polyolefin resin, urethane resin, and silicone resin. .. As the support with a release layer, a commercially available product may be used. For example, "SK-1" and "SK-1" manufactured by Lintec Corporation, which are PET films having a release layer containing an alkyd resin-based mold release agent as a main component. Examples include "AL-5", "AL-7", "Lumilar T60" manufactured by Toray Industries, "Purex" manufactured by Teijin Ltd., and "Unipee" manufactured by Unitika Ltd.

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

For the resin sheet, for example, a resin varnish in which a resin composition is dissolved in an organic solvent is prepared, and this resin varnish is applied onto a support using a die coater or the like and further dried to form a resin composition layer. It can be manufactured by.

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

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 depends on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing 30% by mass to 60% by mass of an organic solvent is used, the resin composition is obtained by drying at 50 ° C. to 150 ° C. for 3 to 10 minutes. A layer can be formed.

In the resin sheet, a protective film similar 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). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to suppress the adhesion and scratches of dust and the like on the surface of the resin composition layer. The resin sheet can be rolled up and stored. If the resin sheet has a protective film, it can be used by peeling off the protective film.

[Manufacturing method of wiring board with built-in inductor element and wiring board with built-in inductor element]
(First Embodiment)
A configuration example of the wiring board with a built-in inductor element of the first embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. 1 is a schematic plan view of a wiring board with a built-in inductor element as viewed from one side in the thickness direction. FIG. 2 is a schematic view showing a cut end surface of a wiring board with a built-in inductor element cut at a position indicated by an alternate long and short dash line II-II. FIG. 3 is a schematic plan view for explaining the configuration of the first wiring layer in the wiring board with a built-in inductor element. Hereinafter, the wiring board with a built-in inductor element may be simply referred to as a “wiring board”.

The wiring board has a magnetic layer which is a cured body of the resin composition (resin composition layer) and a conductive structure in which at least a part thereof is embedded in the magnetic layer. It includes an inductor element that extends in the thickness direction of the magnetic layer and is composed of a part of the magnetic layer surrounded by a conductive structure.

It is assumed that the frequency at which the inductor element included in the wiring board of the present embodiment can function is 10 MHz to 200 MHz. Further, the inductor element provided in the wiring board of this embodiment is assumed to be a power supply system.

As shown in FIGS. 1 and 2, the wiring board 10 is a build-up wiring board having a build-up magnetic layer. The wiring board 10 includes a core base material 20. The core base material 20 has a first main surface 20a and a second main surface 20b opposite to the first main surface 20a. The core base material 20 is an insulating substrate. The core base material 20 may be an inner layer circuit board in which wiring or the like is built within the thickness thereof.

Examples of the material of the core base material 20 include an insulating base material such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate.

The core base material 20 has a first wiring layer 42 provided on the first main surface 20a and an external terminal 24 provided on the second main surface 20b. The first wiring layer 42 and the second wiring layer 44 include a plurality of wirings. In the illustrated example, only the wiring constituting the coiled conductive structure 40 of the inductor element is shown. The external terminal 24 is a terminal for electrically connecting to an external device or the like (not shown). The external terminal 24 can be configured as a part of the wiring layer provided on the second main surface 20b.

Examples of the conductor material that can constitute the first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring include gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, and nickel. Included is one or more metals selected from the group consisting of titanium, tungsten, iron, tin and indium. The first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wirings may be made of a single metal or an alloy, and the alloy may be selected from, for example, the above group. Examples include alloys of two or more metals (eg, nickel-chromium alloys, copper-nickel alloys and copper-titanium alloys). Above all, from the viewpoint of versatility, cost, ease of patterning, etc., it is possible to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloy, copper nickel alloy, copper titanium alloy. It is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, and even more preferably copper.

Even if the first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring have a single layer structure, a single metal layer made of a different type of metal or alloy or a plurality of alloy layers are laminated. It may have a layered structure. When the first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring have a multi-layer structure, the layer in contact with the magnetic layer is a single metal layer of chromium, zinc, or titanium, or an alloy of nickel-chromium alloy. It is preferably a layer.

The thickness of the first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring depends on the design of the desired multilayer printed wiring board, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

The thickness of the first wiring layer 42 and the external terminal 24 included in the core base material 20 is not particularly limited. The thickness of the first wiring layer 42 and the external terminal 24 is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, still more preferably 40 μm or less, and particularly preferably 40 μm or less, from the viewpoint of thinning. Is 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit of the thickness of the external terminal 24 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more.

The line (L) / space (S) ratio of the first wiring layer 42 and the external terminal 24 is not particularly limited, but is usually 900/900 μm or less from the viewpoint of reducing surface irregularities and obtaining a magnetic layer having excellent smoothness. It is preferably 700/700 μm or less, more preferably 500/500 μm or less, still more preferably 300/300 μm or less, still more preferably 200/200 μm or less. The lower limit of the line / space ratio is not particularly limited, but is preferably 1/1 μm or more from the viewpoint of improving the embedding of the resin composition in the space.

Examples of the core base material 20 include a wiring board made of a glass cloth base material epoxy resin double-sided copper-clad laminate "R1515A" manufactured by Panasonic Corporation and having a copper layer patterned to form a wiring layer.

The core base material 20 has a plurality of through holes 22 penetrating the core base material 20 from the first main surface 20a to the second main surface 20b. The through hole 22 is provided with wiring 22a in the through hole. The wiring 22a in the through hole electrically connects the first wiring layer 42 and the external terminal 24.

As shown in FIG. 3, the first wiring layer 42 has a spiral wiring portion for forming the coiled conductive structure 40 and a rectangular land 42a electrically connected to the wiring 22a in the through hole. And include. In the illustrated example, the spiral wiring portion includes a bending portion that bends at a right angle to the linear portion and a detour portion that bypasses the land 42a. In the illustrated example, the spiral wiring portion of the first wiring layer 42 has a substantially rectangular outline as a whole, and has a shape of being wound counterclockwise from the center side toward the outside thereof.

On the first main surface 20a side of the core base material 20 provided with the first wiring layer 42, the first magnetic layer 32 covers the first wiring layer 42 and the first main surface 20a exposed from the first wiring layer 42. Is provided.

Since the first magnetic layer 32 is a layer derived from the resin sheet already described, the first wiring layer 42 is excellent in sealing property. Further, since the first magnetic layer 32 is formed by using the resin sheet, the relative magnetic permeability in the frequency range of 10 MHz to 200 MHz is improved, and the magnetic loss is usually reduced.

The first magnetic layer 32 is provided with a via hole 36 that penetrates the first magnetic layer 32 in the thickness direction thereof.

A second wiring layer 44 is provided on the first magnetic layer 32. The second wiring layer 44 includes a spiral wiring portion for forming the coiled conductive structure 40. In the illustrated example, the spiral wiring portion includes a linear portion and a bent portion that bends at a right angle. In the illustrated example, the spiral wiring portion of the second wiring layer 44 has a substantially rectangular outline as a whole, and has a shape of being wound clockwise from the center side toward the outside thereof.

A wiring 36a in the via hole is provided in the via hole 36. One end of the spiral wiring portion of the second wiring layer 44 on the center side is electrically connected to one end of the spiral wiring portion of the first wiring layer 42 on the center side by the wiring 36a in the via hole. .. The other end of the spiral wiring portion of the second wiring layer 44 on the outer peripheral side is electrically connected to the land 42a of the first wiring layer 42 by the wiring 36a in the via hole. Therefore, the other end of the spiral wiring portion of the second wiring layer 44 on the outer peripheral side is electrically connected to the external terminal 24 via the via hole wiring 36a, the land 42a, and the through hole wiring 22a.

The coil-shaped conductive structure 40 has a spiral wiring portion that is a part of the first wiring layer 42, a spiral wiring portion that is a part of the second wiring layer 44, and a spiral wiring portion of the first wiring layer 42. It is composed of the wiring 36a in the via hole that electrically connects the wiring portion of the second wiring layer 44 and the spiral wiring portion of the second wiring layer 44.

A second magnetic layer 34 is provided on the first magnetic layer 32 provided with the second wiring layer 44 so as to cover the second wiring layer 44 and the first magnetic layer 32 exposed from the second wiring layer 44. ..

The second magnetic layer 34 is a layer derived from the resin sheet already described as in the case of the first magnetic layer 32, and the resin composition layer of the resin sheet is excellent in fluidity at the time of forming the magnetic layer, so that the second magnetic layer 34 is the second. The wiring layer 44 has excellent sealing properties. Further, since the second magnetic layer 34 is formed by using the resin sheet, the relative magnetic permeability is improved, and the magnetic loss is usually reduced.

The first magnetic layer 32 and the second magnetic layer 34 constitute a magnetic portion 30 that can be seen as an integral magnetic layer. Therefore, the coil-shaped conductive structure 40 is provided so that at least a part thereof is embedded in the magnetic portion 30. That is, in the wiring plate 10 of the present embodiment, the inductor element extends in the thickness direction of the coiled conductive structure 40 and the magnetic portion 30, and is surrounded by the coiled conductive structure 40. It is composed of a core that is a part of the core.

In the present embodiment, an example in which the coiled conductive structure 40 includes two wiring layers of the first wiring layer 42 and the second wiring layer 44 has been described, but three or more wiring layers (and three or more layers) have been described. The coiled conductive structure 40 can also be formed by the build-up magnetic layer). In this case, the spiral wiring portion of the wiring layer (not shown) arranged so as to be sandwiched between the wiring layer of the uppermost layer and the wiring layer of the lowermost layer has one end thereof on the uppermost layer side and is arranged in the immediate vicinity. One end of the spiral wiring part of the wiring layer that is electrically connected to one end of the spiral wiring part of the wiring layer, and the other end is the lowest layer side and is arranged closest to the spiral wiring part of the wiring layer. It is electrically connected to the part.

According to the wiring board according to the present embodiment, since the magnetic layer is formed by the resin sheet, the specific magnetic permeability of the formed magnetic layer can be increased and the amount of warpage can be reduced.

Hereinafter, a method for manufacturing a wiring board with a built-in inductor element according to the first embodiment will be described with reference to FIG.

The method for manufacturing a wiring plate according to the present embodiment includes a magnetic portion including a first magnetic layer and a second magnetic layer, and a coiled conductive structure in which at least a part thereof is embedded in the magnetic portion. A method for manufacturing a wiring plate including an inductor element composed of a conductive structure and a part of a magnetic portion, wherein the resin sheet according to the present embodiment and a core base material provided with a first wiring layer are provided. A step of laminating a resin composition layer of a resin sheet on a core base material, a step of thermally curing the resin composition layer to form a first magnetic layer, and a step of forming a via hole in the first magnetic layer. A step of roughening the first magnetic layer on which a via hole is formed, a step of forming a second wiring layer on the first magnetic layer, and electrically connecting the first wiring layer and the second wiring layer. The process of forming the wiring inside the via hole to be connected, the second wiring layer, and the first magnetic layer on which the wiring inside the via hole is formed are further laminated with the resin sheet according to the present embodiment and heat-cured to form the second magnetic layer. A coiled conductive structure including a part of the first wiring layer, a part of the second wiring layer, and wiring in the via hole, and a coiled conductive structure extending in the thickness direction of the magnetic portion. It includes a step of forming an inductor element including a part of a magnetic part surrounded by.

First, a core base material (inner layer) provided with a first wiring layer 42 provided on the first main surface 20a, an external terminal 24 provided on the second main surface 20b, a through hole 22, and a through hole inner wiring 22a. Circuit board) 20 and a resin sheet are prepared.

<Step of forming the first magnetic layer>
Next, the first magnetic layer 32 is formed. First, a laminating step of laminating the resin composition layer of the resin sheet so as to be in contact with the first wiring layer 42 of the core base material is performed.

The conditions of the laminating process are not particularly limited, and the conditions used for forming the magnetic layer (build-up magnetic layer) using the resin sheet can be adopted. For example, it can be performed by pressing a heated metal plate such as a stainless steel end plate from the support side of the resin sheet. In this case, instead of directly pressing the metal plate, it is preferable to press through an elastic member made of heat-resistant rubber or the like so that the resin sheet sufficiently follows the unevenness of the surface of the core base material 20. The press temperature is preferably in the range of 70 ° C to 140 ° C, the press pressure is preferably in the range of 1 kgf / cm ² to 11 kgf / cm ² (0.098 MPa to 1.079 MPa), and the press time is preferably 5. The range is from 1 second to 3 minutes.

Further, the laminating step is preferably carried out under a reduced pressure of 20 mmHg (26.7 hPa) or less. The laminating step can be carried out using a commercially available vacuum laminator. Examples of the vacuum laminator on the market include a vacuum pressurizing laminator manufactured by Meiki Co., Ltd., a vacuum applicator manufactured by Nikko Materials Co., Ltd., and the like.

After the completion of the laminating step, a smoothing step of heating and pressurizing the resin sheet laminated on the core base material 20 may be performed.

The smoothing step is generally carried out by heating and pressurizing the resin sheet laminated on the core base material 20 with a heated metal plate or metal roll under normal pressure (atmospheric pressure). As the conditions for the heating and pressure treatment, the same conditions as those for the laminating step can be used.

The laminating and smoothing steps can also be performed continuously using the same vacuum laminator.

A step of peeling off the support derived from the resin sheet is performed at an arbitrary timing after the laminating step or the smoothing step is performed. The step of peeling the support can be mechanically performed by, for example, a commercially available automatic peeling device.

Next, a thermosetting step of thermosetting the resin composition layer laminated on the core base material 20 to form a magnetic layer (build-up magnetic layer) is carried out.

The conditions of the thermosetting step are not particularly limited, and the conditions usually adopted when forming the insulating layer of the multilayer printed wiring board can be applied.

The conditions of the thermosetting step can be arbitrarily suitable depending on the composition of the resin composition used for the resin composition layer and the like. The conditions of the thermosetting step are, for example, a curing temperature in the range of 120 ° C. to 240 ° C. (preferably in the range of 150 ° C. to 210 ° C., more preferably a range of 170 ° C. to 190 ° C.), and a curing time of 5 minutes to 90 minutes. (Preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes).

Before carrying out the thermosetting step, a step of preheating the resin composition layer at a temperature lower than the curing temperature may be carried out. Prior to carrying out the thermosetting step, the resin composition layer is applied to the resin composition layer at a temperature of, for example, 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) for 5 minutes or longer (preferably). May be preheated for 5 to 150 minutes, more preferably 15 to 120 minutes). Preheating is preferably performed under atmospheric pressure (normal pressure).

By the above steps, the first magnetic layer 32 provided on the core base material 20 can be formed.

Further, the step of forming the first magnetic layer 32 on the core base material 20 can also be performed using a general vacuum hot press machine. For example, it can be performed by pressing the core base material 20 and the resin composition layer from the support side using a heated metal plate such as a SUS plate. The pressing conditions are such that the degree of decompression is usually 1 × 10 ⁻² MPa or less, preferably 1 × 10 ^-3 MPa or less. Although heating and pressurization can be performed in one step, it is preferable to change the pressing conditions as two or more steps from the viewpoint of controlling the seepage of the resin. For example, the press condition of the first stage is a temperature of 70 ° C. to 150 ° C., the pressure is in the range of 1 kgf / cm ² to 15 kgf / cm ² , and the press condition of the second stage is a temperature of 150 ° C. to 200 ° C. The pressure is preferably in the range of 1 kgf / cm ² to 40 kgf / cm ² . The time of each step is preferably 30 minutes to 120 minutes. Examples of commercially available vacuum hot press machines include "MNPC-V-750-5-200" manufactured by Meiki Co., Ltd. and "VH1-1603" manufactured by Kitagawa Seiki Co., Ltd.

<Beer hall forming process>
A via hole 36 is formed in the formed first magnetic layer 32. The via hole 36 serves as a path for electrically connecting the first wiring layer 42 and the second wiring layer 44. The via hole 36 can be formed by a known method using a drill, a laser, a plasma, or the like in consideration of the characteristics of the first magnetic layer 32. For example, if the support of the resin sheet remains at this point, the via hole 36 can be formed by irradiating the first magnetic layer 32 with laser light via the support.

Examples of the laser light source that can be used for forming the via hole 36 include a carbon dioxide laser, a YAG laser, and an excimer laser. Of these, a carbon dioxide laser is preferable from the viewpoint of processing speed and cost.

The formation of the via hole 36 can be carried out using a commercially available laser device. Examples of commercially available carbon dioxide laser devices include "LC-2E21B / 1C" manufactured by Hitachi Via Mechanics, "ML605GTWII" manufactured by Mitsubishi Electric, and a substrate drilling laser machine manufactured by Matsushita Welding System.

<Roughening process>
Next, a roughening step of roughening the first magnetic layer 32 on which the via hole 36 is formed is performed. The procedure and conditions of the roughening step are not particularly limited, and the procedures and conditions usually used in the method of manufacturing a multilayer printed wiring board can be adopted. As the roughening step, for example, it is preferable to carry out by dry sputtering, and by carrying out the swelling treatment with a swelling liquid, the roughening treatment with an oxidizing agent, and the neutralization treatment with a neutralizing liquid in this order, the first magnetic layer 32 May be roughened.

The roughening step may also serve as a so-called desmear step for removing smear of the via hole 36 formed in the first magnetic layer 32.

Further, a desmear step may be carried out on the via hole 36 separately from the roughening step. The desmear step may be a wet desmear step or a dry desmear step.

<Formation of the second wiring layer>
Next, the second wiring layer 44 is formed on the first magnetic layer 32 in which the roughening step (and the desmear step) has been performed.

The second wiring layer 44 can be formed by plating. The second wiring layer 44 is formed by, for example, a conventionally known technique such as an electroless plating step, a mask pattern forming step, an electrolytic plating step, a semi-additive method including a flash etching step, and a full additive method, so that the desired wiring can be obtained. It can be formed as a wiring layer containing a pattern. By the process of forming the second wiring layer 44, the wiring 36a in the via hole is also formed in the via hole 36.

When the first magnetic layer 32 is a build-up magnetic layer and the second wiring layer 44 is a build-up layer which is a build-up wiring layer, when one or more build-up layers are required in the wiring board of the present embodiment. The series of steps already described from the step of forming the first magnetic layer 32 to the step of forming the second wiring layer 44 may be repeated one or more times.

<Formation of the second magnetic layer>
Next, the second magnetic layer 34 is formed on the first magnetic layer 32 on which the second wiring layer 44 and the wiring 36a in the via hole are formed. The second magnetic layer 34 may be formed by the same step using the same material as the first magnetic layer 32 forming step including the resin sheet laminating step, the smoothing step, and the thermosetting step already described.

Through the above steps, the coiled conductive structure 40 having at least a part embedded in the magnetic portion 30 has a part of the first wiring layer 42, a part of the second wiring layer 44, and the wiring 36a in the via hole. A wiring board 10 including an inductor element including a coiled conductive structure 40 including a portion of the magnetic portion 30 extending in the thickness direction of the magnetic portion 30 and surrounded by the coiled conductive structure 40. Can be manufactured.

(Second Embodiment)
A configuration example of the wiring board with a built-in inductor element of the second embodiment will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and duplicate description may be omitted.

As shown in FIG. 11, the wiring plate 11 has a magnetic layer which is a cured body of the resin composition (resin composition layer), and a conductive structure in which at least a part thereof is embedded in the magnetic layer. Includes this conductive structure and an inductor element that extends in the thickness direction of the magnetic layer and is composed of a portion of the magnetic layer surrounded by the conductive structure. The wiring board 11 is a build-up wiring board having a build-up magnetic layer. The wiring board 11 is different from the wiring board 10 of the first embodiment in that it does not have a core base material.

It is assumed that the frequency at which the inductor element included in the wiring board 11 can function is 10 MHz to 200 MHz. Further, the inductor element included in the wiring board 11 is assumed to be a power supply system.

The wiring board 11 includes a first wiring layer 42, a second wiring layer 44, and a third wiring layer 46. The first wiring layer 42, the second wiring layer 44, and the third wiring layer 46 usually include a plurality of wirings. In the illustrated example, only the wiring constituting the coiled conductive structure 40 of the inductor element is shown. The first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring are the same as those of the first wiring layer 42, the second wiring layer 44, the external terminal 24, and other wiring in the first embodiment. Is.

The conductor material that can form the third wiring layer 46 is the same as the conductor material that can form the first wiring layer 42 in the first embodiment. The thickness of the third wiring layer 46 is the same as the thickness of the first wiring layer 42 in the first embodiment.

The third wiring layer 46 may have a single-layer structure, a single metal layer made of different types of metals or alloys, or a multi-layer structure in which two or more alloy layers are laminated. When the third wiring layer 46 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.

The first magnetic layer 32, the second magnetic layer 34, and the third magnetic layer 38 constitute a magnetic portion 30 that can be seen as an integral magnetic layer. The first magnetic layer 32 and the second magnetic layer 34 are the same as the first magnetic layer 32 and the second magnetic layer 34 in the first embodiment.

The third magnetic layer 38 is a layer derived from the resin sheet already described, and the resin composition layer of the resin sheet has excellent fluidity at the time of forming the magnetic layer, so that the sealing property of the second wiring layer 44 is improved. Are better. Further, since the third magnetic layer 38 is formed by using the resin sheet, the relative magnetic permeability in the frequency range of 10 MHz to 200 MHz is improved, and the magnetic loss is usually reduced.

Via holes 36 are formed in the first magnetic layer 32 and the second magnetic layer 34. A wiring 36a in the via hole is provided in the via hole 36. The first wiring layer 42, the second wiring layer 44, and the third wiring layer 46 are electrically connected by the wiring 36a in the via hole or the like.

In the present embodiment, an example in which the coiled conductive structure 40 includes three wiring layers of a first wiring layer 42, a second wiring layer 44, and a third wiring layer 46 has been described, but four or more layers have been described. The coiled conductive structure 40 can also be formed by a wiring layer (and four or more built-up magnetic layers). In this case, the spiral wiring portion of the wiring layer (not shown) arranged so as to be sandwiched between the wiring layer of the uppermost layer and the wiring layer of the lowermost layer has one end thereof on the uppermost layer side and is arranged in the immediate vicinity. One end of the spiral wiring part of the wiring layer that is electrically connected to one end of the spiral wiring part of the wiring layer, and the other end is the lowest layer side and is arranged closest to the spiral wiring part of the wiring layer. It is electrically connected to the part.

According to the wiring board according to the present embodiment, since the magnetic layer is formed by the resin sheet, the specific magnetic permeability and flame retardancy of the formed magnetic layer can be increased, and the amount of warpage can be reduced.

Hereinafter, a method for manufacturing a wiring board with a built-in inductor element according to the second embodiment will be described with reference to FIGS. 4 to 11. The description of the part where the description overlaps with that of the first embodiment will be omitted as appropriate.

The method for manufacturing a wiring board according to this embodiment is
(1) A step of preparing a base material 50 with a metal layer with a carrier having a base material 51 and a metal layer with a carrier 52 provided on at least one surface of the base material 51.
(2) A step of laminating a resin composition layer of a resin sheet on a base material 50 with a metal layer with a carrier and thermosetting the resin composition layer to form a first magnetic layer 32.
(3) A step of forming the first wiring layer 42 on the first magnetic layer 32,
(4) A step of laminating a resin composition layer of a resin sheet on a first wiring layer 42 and a first magnetic layer 32 and thermosetting the resin composition layer to form a second magnetic layer 34.
(5) A step of forming a via hole 36 in the second magnetic layer 34 and roughening the second magnetic layer 34 on which the via hole 36 is formed.
(6) A step of forming the second wiring layer 44 on the second magnetic layer 34,
(7) A step of laminating a resin composition layer of a resin sheet on a second wiring layer 44 and a second magnetic layer 34 and thermosetting the resin composition layer to form a third magnetic layer 38.
(8) Step of removing the base material 50 with a metal layer with a carrier,
(9) A step of forming a via hole (not shown) in the third magnetic layer 38 and roughening the third magnetic layer 38 on which the via hole is formed.
(10) A step of forming a via hole 36 in the first magnetic layer 32 and roughening the first magnetic layer 32 on which the via hole 36 is formed.
It includes (11) a step of forming a third wiring layer 46 on the third magnetic layer 38, and (12) a step of forming an external terminal 24 on the first magnetic layer 32.

The steps (9) and the step (10) may be performed in a different order, or may be performed at the same time. Further, the steps (11) and the steps (12) may be performed in a different order or at the same time.

<Process (1)>
The step (1) is a step of preparing a base material 50 with a metal layer with a carrier having a base material 51 and a metal layer 52 with a carrier provided on at least one surface of the base material 51. As an example shown in FIG. 4, the base material 50 with a metal layer with a carrier is usually provided with a base material 51 and a metal layer 52 with a carrier on at least one surface of the base material 51. From the viewpoint of improving the workability of the step (8) described later, the metal layer 52 with a carrier is preferably configured so that the first metal layer 521 and the second metal layer 522 are provided in this order from the base material 51 side.

The material of the base material 51 is the same as that of the core base material in the first embodiment. Examples of the material of the metal layer 52 with a carrier include a copper foil with a carrier, a metal foil with a peelable support, and the like. As the base material 50 with a metal layer with a carrier, a commercially available product can be used. Examples of commercially available products include "MT-EX" manufactured by Mitsui Mining & Smelting Co., Ltd.

<Process (2)>
In the step (2), as shown by an example in FIG. 5, the resin composition layer of the resin sheet is laminated on the base material 50 with the metal layer with a carrier, and the resin composition layer is thermally cured to form the first magnetic layer 32. This is the process of forming.

The formation of the first magnetic layer 32 in the step (2) can be formed by the same method as the formation of the first magnetic layer in the first embodiment.

After the step (2) is completed, a roughening step may be performed on the formed first magnetic layer, if necessary. The roughening step can be performed by the same method as the roughening step performed on the first magnetic layer in the first embodiment.

<Process (3)>
The step (3) is a step of forming the first wiring layer 42 on the first magnetic layer 32, as shown by an example in FIG. The first wiring layer 42 can be formed by plating. The first wiring layer 42 can be formed by the same method as the formation of the second wiring layer 44 in the first embodiment. Further, as the first wiring layer 42, the same conductor material as the first wiring layer in the first embodiment can be used.

<Process (4)>
In the step (4), as shown by an example in FIG. 7, the resin composition layer of the resin sheet is laminated on the first wiring layer 42 and the first magnetic layer 32, and the resin composition layer is thermosetting. 2 This is a step of forming the magnetic layer 34.

The second magnetic layer 34 can be formed by the same method as in the above-mentioned step (2). As the resin sheet forming the second magnetic layer 34, the same resin sheet as that used when forming the first magnetic layer 32 may be used, or a different resin sheet may be used.

<Process (5)>
The step (5) is a step of forming a via hole 36 in the second magnetic layer 34 and roughening the second magnetic layer 34 in which the via hole 36 is formed, as shown by an example in FIG. A wiring 36a in the via hole is provided in the via hole 36. The via hole 36 serves as a path for electrically connecting the first wiring layer 42 and the second wiring layer 44.

The via hole 36 can be formed by the same method as the via hole forming step in the first embodiment. Further, the roughening treatment can be performed by the same method as the roughening step performed on the first magnetic layer in the first embodiment.

<Step (6)>
The step (6) is a step of forming the second wiring layer 44 on the second magnetic layer 34, as shown by an example in FIG. For details, the second wiring layer 44 is formed on the via hole 36 in the second magnetic layer 34. The second wiring layer 44 can be formed by plating. The second wiring layer 44 can be formed by the same method as the formation of the second wiring layer 44 in the first embodiment. Further, as the second wiring layer 44, the same conductor material as the second wiring layer in the first embodiment can be used.

<Process (7)>
In the step (7), as shown by an example in FIG. 9, the resin composition layer of the resin sheet is laminated on the second wiring layer 44 and the second magnetic layer 34, and the resin composition layer is thermosetting. 3 This is a step of forming the magnetic layer 38.

The third magnetic layer 38 can be formed by the same method as in the above-mentioned step (2). As the resin sheet forming the third magnetic layer 38, the same resin sheet as the resin sheet used for forming the first magnetic layer 32 and the second magnetic layer 34 may be used, or different ones may be used.

<Process (8)>
Step (8) is a step of removing the base material 50 with a metal layer with a carrier, as shown in FIG. 10 as an example. The method for removing the base material 50 with a metal layer with a carrier is not particularly limited. In one preferred embodiment, the base material 51 and the first metal layer 521 are peeled off at the interface between the first metal layer 521 and the second metal layer 522, and the second metal layer 522 is removed by etching with, for example, an aqueous solution of copper chloride. If necessary, the base material 50 with a metal layer with a carrier may be peeled off while the third magnetic layer 38 is protected by a protective film.

<Process (9)>
The step (9) is a step of forming a via hole (not shown in FIG. 11) on the third magnetic layer 38 and roughening the third magnetic layer 38 on which the via hole is formed. Wiring in the via hole is provided in the via hole. The via hole serves as a path for electrically connecting the second wiring layer 44 and the third wiring layer 46. The via hole can be formed and roughened by the same method as in the first embodiment.

<Process (10)>
The step (10) is a step of forming a via hole 36 in the first magnetic layer 32 and roughening the first magnetic layer 32 in which the via hole 36 is formed, as shown by an example in FIG. Specifically, a via hole 36 is formed on the surface side of the first magnetic layer 32 on the side where the base material with a metal layer with a carrier 50 is removed, and an external terminal 24 is formed on the via hole 36. A wiring 36a in the via hole is provided in the via hole 36. The via hole 36 serves as a path for electrically connecting the first wiring layer 42 and the external terminal 24. The via hole 36 can be formed and roughened by the same method as in the first embodiment.

<Process (11)>
The step (11) is a step of forming the third wiring layer 46 on the third magnetic layer 38, as shown by an example in FIG. For details, after roughening the via hole (not shown) formed in the third magnetic layer 38, the third wiring layer 46 is formed on the via hole. The third wiring layer 46 can be formed by the same method as the second wiring layer 44 in the first embodiment, and the same conductor material as the first and second wiring layers in the first embodiment is used. Can be done.

<Process (12)>
The step (12) is a step of forming the external terminal 24 on the first magnetic layer 32, as shown in FIG. 11 as an example. For details, after roughening the via hole 36 formed in the first magnetic layer 32, the external terminal 24 is connected on the via hole 36.

By the above steps, it is possible to manufacture a wiring board without a base material and including an inductor element. This inductor element includes a coiled conductive structure 40 and a part of the magnetic portion 30 extending in the thickness direction of the magnetic portion 30 and surrounded by the coiled conductive structure 40. The coiled conductive structure 40 includes a part of the first wiring layer 42, a part of the second wiring layer 44, a part of the third wiring layer 46, and the wiring 36a in the via hole.

When the first magnetic layer 32 is a build-up magnetic layer and the second wiring layer 44 is a build-up layer which is a build-up wiring layer, when one or more build-up layers are required in the wiring board of the present embodiment. The series of steps already described from the step of forming the first magnetic layer 32 to the step of forming the second wiring layer 44 may be repeated one or more times.

By using the resin sheet of the present invention, the specific magnetic permeability can be improved and a magnetic layer having a reduced amount of warpage can be formed. Therefore, the resin sheet is composed of a part of the magnetic layer without forming an air core structure. It is possible to provide a wiring board in which a higher-performance inductor element including a magnetic core is incorporated in a simpler process.

The wiring board according to this embodiment can be used as a wiring board for mounting an electronic component such as a semiconductor chip, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer board. Further, the wiring board can be used as an individualized chip inductor component, or the chip inductor component can be used as a surface-mounted printed wiring board.

Further, various aspects of the semiconductor device can be manufactured by using such a wiring board. The semiconductor device including such a wiring board can be suitably used for electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircraft, etc.) and the like. ..

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

<Measurement of thermosetting shrinkage rate>
(1) Preparation of Polyimide Film with Resin PET film ("Lumilar R80" manufactured by Toray Co., Ltd.) obtained by mold-releasing the resin varnish produced in Examples and Comparative Examples with an alkyd resin-based mold release agent ("AL-5" manufactured by Lintec Co., Ltd.). , Thickness 38 μm, softening point 130 ° C., hereinafter sometimes referred to as “release PET”), and applied with a die coater so that the thickness of the resin composition layer after drying is 120 μm, from 65 ° C. A resin sheet was obtained by drying at 115 ° C. (average 100 ° C.) for 7 minutes. This resin sheet was cut to a size of 200 mm square. The prepared resin sheet (200 mm square) was subjected to a batch type vacuum pressurizing laminator (2-stage build-up laminator manufactured by Nikko Materials Co., Ltd., CVP700), and the resin composition layer was a polyimide film (Ube Industries Co., Ltd. Iupirex 25S). , 25 μm thick, 240 mm square), laminated on one side so as to be in contact with the center of the smooth surface. Lamination was carried out by reducing the pressure for 30 seconds to reduce the atmospheric pressure to 13 hPa or less, and then crimping at 100 ° C. and a pressure of 0.74 MPa for 30 seconds. As a result, a polyimide film with resin was obtained.

(2) Measurement of initial length The obtained polyimide film with resin is punched from the mold release PET of the resin sheet into a through hole (diameter about 6 mm) from the four corners to about 20 mm of the resin composition layer. After forming one (the holes are tentatively referred to as A, B, C, D in the clockwise direction) and peeling off the release _PET , the length L ( _{LAB, LBC ,} LCD) between the centers of each formed hole is formed. L _DA , L _AC , L _BD ) (see FIG. 12) were measured with a non-contact image measuring instrument (Mitutoyo, Quick Vision, "QVH1X606-PRO III_BHU2G").

(3) Thermosetting of the resin composition layer (2) The polyimide film surface of the polyimide film with resin whose initial length has been measured is a glass cloth base material epoxy resin double-sided copper-clad laminate (0.7 mm) having a size of 255 mm × 255 mm. The resin composition layer is heated by installing it on "R5715ES" manufactured by Matsushita Electric Works Co., Ltd., fixing the four sides with polyimide adhesive tape (width 10 mm), and heating at 100 ° C for 30 minutes and then at 190 ° C for 60 minutes. It was cured to obtain a cured product layer.

(4) Measurement of curing shrinkage rate After heat curing, the polyimide adhesive tape is peeled off, the polyimide film with a cured product layer is removed from the laminated plate, and the cured product layer is further peeled off from the polyimide film to form each hole formed in (2). Non-contact image measurement of the length L'(L' _AB , L' _BC , L' _CD , L' _DA , L' _AC , L' _BD ) between the centers of the film as well as the length L. Measured with a vessel.

The shrinkage rate s1 _AB after curing of the length _LAB between the holes A and the holes B was determined by the following formula (1). Similarly, the shrinkage rates of _LBC , _{LCD, LDA, LAC and LBD after curing were determined as s1 BC , s1 CD , s1 DA , s1 AC} and s1 _DA .
s1 _AB = (LA _AB - _{L'AB) / L AB (} 1)

The curing shrinkage rate of the cured product layer was calculated by the following formula (2).
Curing shrinkage rate [shrinkage rate in the xy direction: S1] (%)
= {(S1 _AB + s1 _BC + s1 _CD + s1 _DA + s1 _AC + s1 _DA ) / 6} x 100 (2)

<Warp test>
The resin varnish produced in Examples and Comparative Examples was applied onto a mold release PET with a die coater so that the thickness of the resin composition layer after drying was 200 μm, and the temperature was 65 ° C to 115 ° C (average 110 ° C). Was dried for 12 minutes to obtain a resin sheet. This resin sheet was laminated using a batch type vacuum pressurizing laminator (MVLP-500 manufactured by Meiki Co., Ltd.) so that the resin composition layer was in contact with a SUS304 plate having a thickness of 0.2 mm and a thickness of 10 cm × 10 cm. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing at 100 ° C. and a pressure of 0.74 MPa for 30 seconds. The release PET of the laminated resin sheet was removed and heat-cured at 190 ° C. for 90 minutes to obtain a sample for warp evaluation.

Place the obtained warp evaluation sample on a smooth table with the surface on the side where the central part becomes the convex part facing down, and measure the distance between the smooth table and the part where the distance between the warp evaluation sample is the largest. The amount of warpage was used. An absolute value of the amount of warpage of less than 15 mm was designated as “◯”, and a value of 15 mm or more was designated as “x”.

<Measurement of peel strength>
(1) Base treatment of inner layer circuit board Both sides of the glass cloth base material epoxy resin double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.8 mm, manufactured by Panasonic, R1515A) on which the inner layer circuit is formed are etched. The copper surface was roughened by etching 1 μm with an agent (CZ8101 manufactured by MEC).

(2) Laminating of resin sheet A copper foil (JXUT-II foil manufactured by JX Nippon Mining & Metals Co., Ltd., thickness 18 μm) was prepared. The resin varnish prepared in Examples and Comparative Examples was applied to the seed copper side of the copper foil, dried at 65 ° C to 115 ° C (average 100 ° C) for 7 minutes, and a resin layer having a thickness of 100 μm was applied. A resin sheet having the above was produced. The resin sheets produced in Examples and Comparative Examples were laminated on both sides of the inner layer circuit board using a batch type vacuum pressurizing laminator (MVLP-500 manufactured by Meiki Co., Ltd.). Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then crimping at 100 ° C. and a pressure of 0.74 MPa for 30 seconds.

(3) Thermosetting of Resin Composition Layer The resin sheet was cured at 130 ° C. for 30 minutes and then at 190 ° C. for 60 minutes under the curing conditions. After that, the copper foil was peeled off.

(4) Electroplating This substrate was electrolytically plated with copper sulfate to form a conductor layer with a thickness of 25 μm. Next, the annealing treatment was performed at 180 ° C. for 60 minutes. This substrate was used as an evaluation substrate.

(5) Measurement of peeling strength (peel strength) of the plated conductor layer Make a notch in the conductor layer of the evaluation board with a width of 10 mm and a length of 100 mm, and peel off one end of the cut, which is an autocom type that is a gripper. The load (kgf / cm) when 35 mm was peeled off in the vertical direction at a speed of 50 mm / min at room temperature was measured by grasping with a testing machine (manufactured by TSE, AC-50C-SL).

<Measurement of average linear thermal expansion coefficient (thermal expansion coefficient), magnetic permeability, and loss coefficient>
(1) Adjustment of the cured product for evaluation Same as the measurement of the curing shrinkage rate except that a PET film (Fluororesin RL50KSE manufactured by Mitsubishi Resin Co., Ltd.) treated with a fluororesin-based mold release agent (ETFE) was used as the support. A resin sheet having the same resin composition layer as the resin varnish produced in each Example and each Comparative Example was obtained. The obtained resin sheet was heated at 190 ° C. for 90 minutes to thermally cure the resin composition layer, and the PET film was peeled off to obtain a sheet-like cured product.

(2) Measurement of average linear thermal expansion coefficient (coefficient of thermal expansion) The obtained cured product for evaluation was cut into test pieces having a width of 5 mm and a length of 15 mm, and a thermomechanical analyzer ("Thermo Plus TMA8310" manufactured by Rigaku Co., Ltd.). ) Was used for thermomechanical analysis by the tensile weighting method. Specifically, after the test piece was attached to the thermomechanical analyzer, measurements were taken twice in succession under the measurement conditions of a load of 1 g and a heating rate of 5 ° C./min. Then, in the second measurement, the average linear thermal expansion coefficient (α1; ppm / ° C.) in the plane direction in the range of 30 ° C. to 150 ° C. was calculated. This operation was performed three times, and the average value is shown in the table.

(3) Measurement of relative magnetic permeability (permeability) and loss coefficient The obtained cured product for evaluation was cut into test pieces having a width of 5 mm and a length of 18 mm to prepare an evaluation sample. This evaluation sample was sampled using "HP8632B" manufactured by Agilent Technologies, with a measurement frequency in the range of 1 MHz to 10 GHz by the short-circuit stripline method, and magnetic permeability (μ') and magnetic permeability at room temperature of 23 ° C. The loss (μ'') was measured. Further, the magnetic permeability and the magnetic permeability loss when the measurement frequency was 100 MHz were measured, and the loss coefficient was obtained. The loss coefficient was calculated from the following formula.
tan δ = μ'/ μ''

<Example 1>
10 parts of bisphenol A type epoxy resin (Mitsubishi Chemical's "828US", epoxy equivalent about 180), 10 parts of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent about 269), cresol novolak type epoxy resin ( DIC "N-680", epoxy equivalent 210) 10 parts, naphthylene ether type epoxy resin (DIC "EXA-7311", epoxy equivalent 277) 20 parts, magnetic filler (Epson Atmix "AW2-" 08PF3F ”, Fe—Cr—Si based alloy (amorphous), average particle size 3.0 μm) 735 parts, triazine skeleton-containing phenol resin (“LA-7054” manufactured by DIC, hydroxyl equivalent of about 125, solid content 60% MEK 10 parts of solution), 6 parts of active ester curing agent (“HPC-8000-65T” manufactured by DIC, a toluene solution having an active group equivalent of about 223 and a solid content of 65%), and an amphoteric polyether block copolymer (Dow Chemical Co., Ltd.). 6 parts of "Fortegra 100" manufactured by Nisshinbo Chemical Co., Ltd. ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., a toluene solution with a solid content of 50%), 4 parts of an imidazole-based curing accelerator ("1-benzyl-2-" manufactured by Shikoku Kasei Kogyo Co., Ltd.) 3 parts of phenylimidazole (1B2PZ) ", MEK solution with 10% solid content) and 7 parts of phenoxy resin (" YL7553BH30 "manufactured by Mitsubishi Chemical Co., Ltd., 1: 1 solution of MEK with 30% solid content and cyclohexanone) are mixed at high speed. The resin varnish 1 was produced by uniformly dispersing it with a rotary mixer.

<Example 2>
In Example 1, the amount of amphipathic polyether block copolymer (“Fortegra 100” manufactured by Dow Chemical Co.) was changed from 6 parts to 3 parts, and the magnetic filler (“AW2-08PF3F” manufactured by Epson Atmix Co., Ltd., Fe-Cr. -Si-based alloy (amorphous), average particle size 3.0 μm) was changed from 735 parts to 710 parts. Except for the above items, the resin varnish 2 was produced in the same manner as in Example 1.

<Example 3>
In Example 1, the amount of amphipathic polyether block copolymer (“Fortegra 100” manufactured by Dow Chemical Co.) was changed from 6 parts to 12 parts, and the magnetic filler (“AW2-08PF3F” manufactured by Epson Atmix Co., Ltd., Fe-Cr. -Si-based alloy (amorphous), average particle size 3.0 μm) was changed from 735 parts to 800 parts. Except for the above items, the resin varnish 3 was produced in the same manner as in Example 1.

<Example 4>
In Example 1, the amount of the bisphenol A type epoxy resin (“828US” manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent of about 180) was changed from 10 parts to 20 parts, and the naphthalene ether skeleton type epoxy resin (“EXA-7311” manufactured by DIC Co., Ltd.” was changed. , The amount of epoxy equivalent 277) was changed from 20 parts to 10 parts. Except for the above items, the resin varnish 4 was produced in the same manner as in Example 1.

<Example 5>
Bisphenol A type epoxy resin (Mitsubishi Chemical's "828US", epoxy equivalent about 180) 23 parts, biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent about 269) 23 parts, magnetic filler (Epson Atmix) "AW2-08PF3F" manufactured by DIC, Fe-Cr-Si based alloy (amorphous), average particle size 3.0 μm) 735 parts, triazine skeleton-containing phenolic resin ("LA-7054" manufactured by DIC, solid with a hydroxyl group equivalent of about 125) 60% MEK solution), 18 parts of active ester curing agent (DIC "HPC-8000-65T", 65% solids toluene solution with active group equivalent of about 223), amphoteric polyether block copolymer ("Fortegura 100" manufactured by Dow Chemical Co.) 6 parts, Carbodiimide compound ("V-03" manufactured by Nisshinbo Chemical Co., Ltd., toluene solution with 50% solid content), 8 parts, amine-based curing accelerator ("Wako Pure Chemical Industries, Ltd." 4-Dimethylaminopyridine (DMAP) ", 1.5 parts of MEK solution with 10% solid content), 14 parts of phenoxy resin (" YL7553BH30 "manufactured by Mitsubishi Chemical Co., Ltd., 1: 1 solution of MEK and cyclohexanone with 30% solid content) Was mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 5.

<Example 6>
20 parts of bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. "828US", epoxy equivalent about 180), 10 parts of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000L", epoxy equivalent about 269), naphthalene ether type epoxy resin ( DIC "EXA-7311", epoxy equivalent 277) 20 parts, magnetic filler (Epson Atmix "AW2-08PF3F", Fe-Cr-Si alloy (amorphous), average particle size 3.0 μm) 735 parts , Triazine skeleton-containing phenolic resin (DIC's "LA-7054", MEK solution with a hydroxyl equivalent of about 125 and a solid content of 60%), 14 parts, active ester curing agent (DIC's "HPC-8000-65T", active group 6 parts of a toluene solution having an equivalent amount of about 223 with a solid content of 65%, 6 parts of an amphoteric polyether block copolymer (“Fortegra 100” manufactured by Dow Chemical Co.), and an imidazole-based curing accelerator (“1-benzyl” manufactured by Shikoku Kasei Kogyo Co., Ltd.). -2-Phenylimidazole (1B2PZ) ", 3 parts of MEK solution with 10% solid content) and 7 parts of phenoxy resin (" YL7553BH30 "manufactured by Mitsubishi Chemical Co., Ltd., 1: 1 solution of MEK and cyclohexanone with 30% solid content) are mixed. Then, the resin varnish 6 was produced by uniformly dispersing it with a high-speed rotating mixer.

<Comparative Example 1>
In Example 1, an amphipathic polyether block copolymer (“Fortegra 100” manufactured by Dow Chemical Co.) was not contained. Except for the above items, the resin varnish 7 was produced in the same manner as in Example 1.

<Comparative Example 2>
In Example 5, an amphipathic polyether block copolymer (“Fortegra 100” manufactured by Dow Chemical Co.) was not contained. Except for the above items, the resin varnish 8 was produced in the same manner as in Example 5.

The results of the above-mentioned Examples and Comparative Examples are shown in the table below. In the table below, the meanings of the abbreviations are as follows.
828US: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent about 180)
NC3000L: Biphenyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent about 269)
N-680: Cresol novolac type epoxy resin (manufactured by DIC, epoxy equivalent 210)
EXA-7311: Naphthalene ether type epoxy resin (manufactured by DIC Corporation, epoxy equivalent 277)
AW2-08PF3F: Magnetic filler (manufactured by Epson Atmix, Fe-Cr-Si alloy (amorphous), average particle size 3.0 μm)
LA-7054: Triazine skeleton-containing phenolic resin (manufactured by DIC, MEK solution having a hydroxyl group equivalent of about 125 and a solid content of 60%)
HPC-8000-65T: Active ester curing agent (manufactured by DIC, toluene solution having an active group equivalent of about 223 and a solid content of 65%)
Fortegra100: Amphiphilic polyether block copolymer (manufactured by Dow Chemical Co.)
V-03: Carbodiimide compound (manufactured by Nisshinbo Chemical Co., Ltd., toluene solution with a solid content of 50%)
1B2PZ: Imidazole-based curing accelerator ("1-benzyl-2-phenylimidazole" manufactured by Shikoku Chemicals Corporation, MEK solution with a solid content of 10%)
DMAP: Amine-based curing accelerator ("4-dimethylaminopyridine" manufactured by Wako Pure Chemical Industries, Ltd., MEK solution with a solid content of 10%)
YL7553BH30: Phenoxy resin (manufactured by Mitsubishi Chemical Corporation, 1: 1 solution of MEK with a solid content of 30% and cyclohexanone)

In each example, it has been confirmed that even when the components (E) to (G) are not contained, the same result as in the above-mentioned example is obtained, although the degree is different.

10 Wiring board 20 Core base material 20a 1st main surface 20b 2nd main surface 22 Through hole 22a Through hole inner wiring 24 External terminal 30 Magnetic part 32 1st magnetic layer 34 2nd magnetic layer 36 Via hole 36a Via hole inner wiring 38 3rd Magnetic layer 40 Coiled conductive structure 42 1st wiring layer 42a Land 44 2nd wiring layer 46 3rd wiring layer 50 Base material with metal layer with carrier 51 Base material 52 Metal layer with carrier 521 1st metal layer 522 2nd Metal layer

Claims (14)

(A) Epoxy resin,
(B) Magnetic filler,
A resin composition containing (C) a curing agent and (D) an amphipathic polyether block copolymer .
The content of the epoxy resin (A) is 1% by mass or more and 20% by mass or less when the non-volatile component in the resin composition is 100% by mass.
(B) The content of the magnetic filler is 75% by mass or more and less than 95% by mass when the non-volatile component in the resin composition is 100% by mass . The resin composition according to claim 1, wherein the content of the component (D) is 0.3% by mass or more and 15% by mass or less when the non-volatile component in the resin composition is 100% by mass. The resin composition according to claim 1 or 2 , wherein the component (D) is a block copolymer containing at least one epoxy resin miscible polyether block segment and at least one epoxy resin immiscible polyether block segment. .. One of the epoxy resin miscible polyether block segments selected from polyethylene oxide block, polypropylene oxide block, poly (ethylene oxide-co-propylene oxide) block, poly (ethylene oxide-ran-propylene oxide) block, and mixtures thereof. The above polyalkylene oxide block,
Claimed that the epoxy resin immiscible polyether block segment is one or more polyalkylene oxide blocks selected from a polybutylene oxide block, a polyhexylene oxide block, a polydodecylene oxide block, and a mixture thereof. 3. The resin composition according to 3. The resin composition according to any one of claims 1 to 4 , further comprising (E) a carbodiimide compound. The resin composition according to any one of claims 1 to 5 , further comprising (F) a thermoplastic resin. The resin composition according to any one of claims 1 to 6 , wherein the component (C) is at least one selected from a triazine skeleton-containing phenol-based curing agent and an active ester-based curing agent. The resin composition according to any one of claims 1 to 7 , wherein the component (A) contains an epoxy resin having a condensed ring structure. The resin according to any one of claims 1 to 8 , wherein the cured product obtained by thermally curing the resin composition at 100 ° C. for 30 minutes and further at 190 ° C. for 60 minutes has a curing shrinkage rate of 0.27% or less. Composition. The invention according to any one of claims 1 to 9 , wherein the cured product obtained by thermally curing the resin composition at 190 ° C. for 90 minutes has a linear thermal expansion coefficient of 3 ppm / ° C. or higher and 30 ppm / ° C. or lower at 30 ° C. to 150 ° C. Resin composition. The resin composition according to any one of claims 1 to 10, which is used for forming a magnetic layer of a wiring board including an inductor element. A resin sheet comprising a support and a resin composition layer provided on the support and formed of the resin composition according to any one of claims 1 to 11. It has a magnetic layer which is a cured product of the resin composition layer of the resin sheet according to claim 12 and a conductive structure in which at least a part thereof is embedded in the magnetic layer.
A wiring board with a built-in inductor element, which includes an inductor element formed of the conductive structure and a part of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. .. A printed wiring board including the wiring board with a built - in inductor element according to claim 13 as an inner layer board.

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