JP7287274B2 - resin composition - Google Patents

Description

The present invention relates to resin compositions. Furthermore, it relates to an adhesive film, a cured product, a wiring board with a built-in inductor element, a chip inductor component, and a printed wiring board obtained using the resin composition.

Due to the demand for smaller and thinner electronic devices in recent years, there is an increasing demand for smaller and thinner printed wiring boards and inductor components (coils) mounted on printed wiring boards. When an inductor component is mounted as a chip component, there is a limit to how thin the printed wiring board can be made. Therefore, it is conceivable to form an inductor in the inner layer of a printed wiring board by forming a magnetic layer on the printed board using an adhesive film containing a magnetic material in the resin composition layer (see, for example, Patent Document 1). .

JP 2015-187260 A

Inductor components include a power supply system and a signal system, and the signal system is required to have a relative magnetic permeability (magnetic permeability) in the gigahertz region or higher. The adhesive film described in Patent Document 1 is assumed to be used in a signal system, and has good relative magnetic permeability in the range of 1 GHz to 3 GHz. On the other hand, the power supply system is required to have a higher relative magnetic permeability in a lower frequency region than the signal system, and is generally used at a frequency of less than 10 MHz. Therefore, conventional resin compositions are optimized for frequencies below 10 MHz or above 1 GHz.

In response to this, the present inventors have focused on a new frequency region of 10 MHz to 200 MHz, and have found that if a high relative magnetic permeability can be achieved in this frequency region, a new inductor component for power supply systems can be obtained. Obtained. However, in order to replace an adhesive film using such a resin composition as a magnetic layer in the interlayer insulating layer portion of a printed wiring board, it is necessary to ensure that the magnetic layer is less likely to warp after formation, flame retardancy, and lamination. Gender is also required.

An object of the present invention is to obtain a cured product that is excellent in flame retardancy, suppresses the amount of warpage, and can improve the relative magnetic permeability in the frequency range of 10 to 200 MHz. An excellent resin composition; an adhesive film, a cured product, a wiring board with a built-in inductor element, a chip inductor component, and a printed wiring board obtained by using the resin composition.

In general, a resin composition containing a magnetic filler has a low relative magnetic permeability in the frequency range of 10 to 200 MHz. It was of limited use. As a result of intensive studies by the present inventors, it was found that each component contained in the resin composition was adjusted so that the elastic modulus at 23° C. of the cured product obtained by thermally curing the resin composition containing the magnetic filler was within a predetermined range. When adjusted, the adhesive film obtained using the resin composition has excellent laminating properties, and the cured product of the resin composition has excellent flame retardancy, suppresses the amount of warpage, and is particularly effective in the frequency range of 10 to 200 MHz. The inventors have found that the magnetic permeability can be improved, and have completed the present invention.

That is, the present invention includes the following contents.
[1] (A) a thermosetting resin,
(B) a curing agent;
(C) a thermoplastic resin, and (D) a magnetic filler, a resin composition containing
A resin composition, wherein a cured product obtained by thermosetting the resin composition has an elastic modulus of 7 GPa or more and 18 GPa or less at 23°C.
[2] The resin composition according to [1], wherein the content of component (D) is 75% by mass or more and less than 95% by mass when the non-volatile matter in the resin composition is 100% by mass.
[3] (E) The resin composition according to [1] or [2], further containing an inorganic filler other than the magnetic filler.
[4] The resin composition according to [3], wherein e1/d1 is 0.02 or more and 0.19 or less, where d1 is the content of component (D) and e1 is the content of component (E). thing.
[5] When the content mass of the resin component in the resin composition is a1 and the content mass of the component (C) is c1, (c1/a1) × 100 is 35 or more and 80 or less [1]- The resin composition according to any one of [4].
[6] The resin composition according to any one of [1] to [5], wherein component (A) is an epoxy resin.
[7] The resin composition according to [6], wherein the epoxy resin is one or more epoxy resins selected from epoxy resins having a biphenyl skeleton and epoxy resins having a condensed ring structure.
[8] The resin composition according to any one of [1] to [7], wherein component (B) is one or more curing agents selected from phenolic curing agents and active ester curing agents.
[9] Component (C) is one or more thermoplastic resins selected from phenoxy resins, polyvinyl acetal resins, butyral resins, and acrylic resins having a weight average molecular weight of 30,000 to 1,000,000 [1] The resin composition according to any one of to [8].
[10] The resin according to any one of [1] to [9], wherein the resin composition forms a sea-island structure consisting of a matrix phase and a dispersed phase, and component (D) is unevenly distributed on the matrix phase side. Composition.
[11] The average particle size of component (D) is 0.01 μm or more and 8 μm or less, and the aspect ratio of component (D) is 2 or less. Resin composition.
[12] The resin composition according to any one of [1] to [11], wherein component (D) is an Fe alloy containing one or more elements selected from Si, Al, and Cr.
[13] The resin composition according to any one of [3] to [12], wherein component (E) is silica.
[14] The resin composition according to any one of [1] to [13], wherein a cured product obtained by thermosetting the resin composition has a relative magnetic permeability of 5 or more at a frequency of 100 MHz.
[15] The resin composition according to any one of [1] to [14], wherein a cured product obtained by thermosetting the resin composition has a magnetic loss of 0.05 or less at a frequency of 100 MHz.
[16] A cured product obtained by thermosetting the resin composition has a relative magnetic permeability of 5 or more and 20 or less at a frequency of 10 MHz, a relative magnetic permeability of 5 or more and 20 or less at a frequency of 100 MHz, and a relative magnetic permeability of 5 or more and 20 or less at a frequency of 1 GHz. The resin composition according to any one of [1] to [15], which is 4 or more and 16 or less and has a relative magnetic permeability of 2 or more and 10 or less at a frequency of 3 GHz or more.
[17] The resin composition according to any one of [1] to [16], which is used for forming a magnetic layer of a wiring board provided with an inductor element.
[18] The resin composition according to [17], wherein the frequency at which the inductor element functions is 10 to 200 MHz.
[19] A cured product obtained by thermosetting the resin composition according to any one of [1] to [18].
[20] An adhesive film 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 [18].
[21] A magnetic layer that is a cured product of the resin composition layer of the adhesive film according to [20], and a conductive structure having at least a portion embedded in the magnetic layer,
Wiring board with a built-in inductor element, comprising: the conductive structure; and an inductor element formed by a portion of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. .
[22] The wiring board with a built-in inductor element according to [21], wherein the frequency at which the inductor element functions is 10 to 200 MHz.
[23] A printed wiring board using the inductor element built-in wiring board according to [21] or [22] as an inner layer substrate.
[24] A chip inductor component obtained by singulating the wiring board with a built-in inductor element according to [21] or [22].
[25] A printed wiring board on which the chip inductor component according to [24] is surface-mounted.

According to the present invention, it is possible to obtain a cured product that is excellent in flame retardancy, suppresses the amount of warpage, and can particularly improve the relative magnetic permeability at a frequency in the range of 10 to 200 MHz. An excellent resin composition; an adhesive film, a cured product, a wiring board with a built-in inductor element, a chip inductor component, and a printed wiring board obtained by using the resin composition can be provided.

FIG. 1 is a schematic plan view of a wiring board with a built-in inductor element according to the first embodiment as an example, viewed from one side in the thickness direction. FIG. 2 is a schematic diagram showing a cut end surface of the wiring board with built-in inductor element of the first embodiment cut at the position indicated by the dashed-dotted line II-II as an example. FIG. 3 is a schematic plan view for explaining the configuration of the first wiring layer of the wiring board with a built-in inductor element 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 the second embodiment as an example. 5 is an enlarged photograph of a cross section of the resin composition of Example 10. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing only schematically shows the shape, size and arrangement of components to the extent that the invention can be understood. The present invention is not limited by the following description, and each component can be changed as appropriate without departing from the gist of the present invention. In the drawings used for the following description, the same components are denoted by the same reference numerals, and redundant description may be omitted. Also, the configuration according to the embodiment of the present invention is not necessarily manufactured or used according to the illustrated arrangement.

[Resin composition]
The resin composition of the present invention is a resin composition containing (A) a thermosetting resin, (B) a curing agent, (C) a thermoplastic resin, and (D) a magnetic filler, wherein the resin composition is The elastic modulus at 23° C. of the thermoset cured product is 7 GPa or more and 18 GPa or less.

As described above, conventional resin compositions containing magnetic fillers have a low relative magnetic permeability in the frequency range of 10 to 200 MHz. range was limited to low frequency applications. In the present invention, by adjusting the contents of the components (A) to (D) contained in the resin composition so that the elastic modulus of the thermoset cured product at 23° C. is 7 GPa or more and 18 GPa or less, It is possible to obtain a cured product that is excellent in flame retardancy, suppresses the amount of warpage, and can improve the relative magnetic permeability in the frequency range of 10 to 200 MHz, and is obtained using a resin composition. The adhesive film has excellent lamination properties.

The resin composition may further contain (E) an inorganic filler other than the magnetic filler, (F) a curing accelerator, (G) a flame retardant, and (H) an organic filler, if necessary. Each component contained in the resin composition will be described in detail below.

<(A) Thermosetting resin>
The resin composition contains (A) a thermosetting resin. As the component (A), a thermosetting resin used for forming an insulating layer of a wiring board can be used, and epoxy resin is particularly preferable.

bisphenol F type epoxy resin; bisphenol S type epoxy resin; bisphenol AF type epoxy resin; dicyclopentadiene type epoxy resin; trisphenol type epoxy resin; tert-butyl-catechol type epoxy resin; naphthol novolac type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, epoxy resin having a condensed ring structure such as anthracene type epoxy resin; glycidylamine type epoxy resin; glycidyl ester type epoxy resin ; cresol novolac type epoxy resin; biphenyl type epoxy resin (epoxy resin having a biphenyl skeleton); linear aliphatic epoxy resin; epoxy resin having a butadiene structure; alicyclic epoxy resin; heterocyclic epoxy resin; Resin; cyclohexanedimethanol type epoxy resin; trimethylol type epoxy resin; tetraphenylethane type epoxy resin and the like. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types. The epoxy resin is preferably one or more selected from bisphenol A type epoxy resins, epoxy resins having a biphenyl skeleton, naphthalene type epoxy resins, and epoxy resins having a condensed ring structure, and epoxy resins having a biphenyl skeleton, and epoxy resins having a condensed ring structure.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. Moreover, the epoxy resin preferably has an aromatic structure, and when two or more epoxy resins are used, at least one of them more preferably has an aromatic structure. When the non-volatile component of the epoxy resin is 100 mass %, at least 50 mass % or more of the epoxy resin preferably has two or more epoxy groups in one molecule. Among them, an epoxy resin that has two or more epoxy groups in one molecule and is liquid at a temperature of 20 ° C. (hereinafter referred to as "liquid epoxy resin"), and three or more epoxy groups in one molecule, It preferably contains an epoxy resin that is solid at a temperature of 20° C. (hereinafter referred to as “solid epoxy resin”). By using both a liquid epoxy resin and a solid epoxy resin as epoxy resins, a resin composition having excellent flexibility can be obtained. Moreover, the breaking strength of the cured product of the resin composition is also improved. Aromatic structures are chemical structures generally defined as aromatic and also include polycyclic aromatic and heteroaromatic rings.

Examples of liquid epoxy resins 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, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, and an ester skeleton. An alicyclic epoxy resin having a type epoxy resins and naphthalene type epoxy resins are more preferred. Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation, and "828US" and "jER828EL" (bisphenol A type epoxy resins) manufactured by Mitsubishi Chemical Corporation. , "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "630", "630LSD" (glycidylamine type epoxy resin), Nippon Steel & Sumikin Chemical Co., Ltd. "ZX1059" (bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation, "Celoxide 2021P" manufactured by Daicel (alicyclic epoxy resin having an ester skeleton) resin), "PB-3600" (epoxy resin having a butadiene structure), "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., "630LSD" manufactured by Mitsubishi Chemical Corporation (glycidyl amine type epoxy resin), ADEKA's "EP-3980S" (glycidylamine type epoxy resin), and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Solid epoxy resins 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, naphthylene ether type epoxy resin, Anthracene type epoxy resin, bisphenol A type epoxy resin and tetraphenylethane type epoxy resin are preferred, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin and biphenyl type epoxy resin are more preferred. Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin), "HP-4700", "HP-4710" (naphthalene-type tetrafunctional epoxy resin), "N-690" ( cresol novolak type epoxy resin), "N-695" (cresol novolak type epoxy resin), "HP-7200" (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), “EPPN-502H” manufactured by Nippon Kayaku Co., Ltd. ( Trisphenol type epoxy resin), "NC7000L" (naphthol novolak type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), Nippon Steel & Sumikin Chemical Co., Ltd. "ESN475V" ( naphthalene type epoxy resin), "ESN485" (naphthol novolac type epoxy resin), Mitsubishi Chemical Corporation's "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin), Osaka Gas Chemicals Co., Ltd. "PG-100", "CG-500", Mitsubishi Chemical Co., Ltd. "YL7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin) , "jER1010" (solid bisphenol A type epoxy resin) and "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When a liquid epoxy resin and a solid epoxy resin are used together as the epoxy resin, the ratio by mass (liquid epoxy resin: solid epoxy resin) is in the range of 1:0.1 to 1:4. preferable. By setting the amount ratio of the liquid epoxy resin to the solid epoxy resin in such a range, i) when used in the form of an adhesive film, moderate tackiness is brought about, and ii) when used in the form of an adhesive film. iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the above effects i) to iii), the ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is 1:0.3 to 1:3.5 by mass. , more preferably 1:0.6 to 1:3, and particularly preferably 1:0.8 to 1:2.5.

From the viewpoint of obtaining a magnetic layer exhibiting good mechanical strength and insulation reliability, the content (% by mass) of component (A) is preferably 0.1 when the non-volatile component in the resin composition is 100% by mass. % by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The upper limit of the epoxy resin content is not particularly limited as long as the effect of the present invention is exhibited, but is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 3% by mass or less.

The content (% by volume) of component (A) is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more when the non-volatile component in the resin composition is 100% by volume. is. The upper limit is not particularly limited as long as the effects of the present invention are exhibited, but is preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less.

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

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

<(B) Curing agent>
The resin composition contains (B) a curing agent. Component (B) is not particularly limited as long as it has the function of curing component (A). When the component (A) is an epoxy resin, the curing agent is an epoxy resin curing agent. Examples of epoxy resin curing agents include phenol-based curing agents, naphthol-based curing agents, active ester-based curing agents, benzoxazine-based curing agents, and cyanate ester-based curing agents. Epoxy resin curing agents may be used singly or in combination of two or more. From the viewpoint of insulating reliability and heat resistance, the curing agent is preferably one or more selected from phenol-based curing agents and active ester-based curing agents.

As the phenolic curing agent and the naphtholic curing agent, a phenolic curing agent having a novolac structure or a naphtholic curing agent having a novolac structure is preferable from the viewpoint of heat resistance and water resistance. From the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenolic curing agent is preferable, and a triazine skeleton-containing phenolic curing agent is more preferable. Among them, a triazine skeleton-containing phenol novolac curing agent is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion to the conductor layer.

Specific examples of phenol-based curing agents and naphthol-based curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and "NHN" and "CBN" manufactured by Nippon Kayaku Co., Ltd. ”, “GPH”, “SN170”, “SN180”, “SN190”, “SN475”, “SN485”, “SN495V”, “SN375”, “SN395” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “TD -2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA -1163”, “KA-1165”, “GDP-6115L” and “GDP-6115H” manufactured by Gun Ei Kagaku Co., Ltd., and the like.

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

Specifically, an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoylated product of phenol novolak are preferred. Among them, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene-type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" represents a bivalent structure consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include, as active ester compounds containing a dicyclopentadiene type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", and "HPC-8000H- 65TM", "EXB-8000L-65TM" (manufactured by DIC), "EXB9416-70BK" (manufactured by DIC) as an active ester compound containing a naphthalene structure, and "DC808" as an active ester compound containing an acetylated phenol novolac ( Mitsubishi Chemical Corporation), "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing a benzoylated phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester curing agent that is an acetylated phenol novolak, "YLH1026" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1030" (manufactured by Mitsubishi Chemical Co., Ltd.), "YLH1048" (manufactured by Mitsubishi Chemical Co., Ltd.) and the like can be mentioned as active ester curing agents that are benzoylated phenol novolacs.

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

Examples of cyanate ester curing agents include bisphenol A dicyanate, polyphenolcyanate, oligo(3-methylene-1,5-phenylenecyanate), 4,4′-methylenebis(2,6-dimethylphenylcyanate), 4,4 '-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanate-3,5-dimethyl Bifunctional cyanate resins such as phenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, phenol Polyfunctional cyanate resins derived from novolacs, cresol novolaks, etc., and prepolymers obtained by partially triazine-forming these cyanate resins. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (both phenol novolac type polyfunctional cyanate ester resins), "BA230" and "BA230S75" (part of bisphenol A dicyanate) manufactured by Lonza Japan Co., Ltd. or a prepolymer that is entirely triazined to form a trimer), and the like.

The ratio of the epoxy resin to the curing agent is [total number of epoxy groups in the epoxy resin]:[total number of reactive groups in the curing agent], and is in the range of 1:0.2 to 1:2. is preferred, a range of 1:0.3 to 1:1.5 is more preferred, and a range of 1:0.4 to 1:1 is even more preferred. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group, or the like, and varies depending on the type of curing agent. In addition, the total number of epoxy groups in the epoxy resin is the sum of the values obtained by dividing the mass of the non-volatile component of each epoxy resin by the epoxy equivalent, and the total number of reactive groups in the curing agent is , is the value obtained by dividing the mass of the non-volatile component of each curing agent by the reactive group equivalent and totaling the values for all curing agents. By setting the ratio between the epoxy resin and the curing agent within this range, the heat resistance of the cured product is further improved.

The resin composition may contain a mixture of a liquid epoxy resin and a solid epoxy resin as an epoxy resin, and at least one selected from the group consisting of a phenol-based curing agent and an active ester-based curing agent as a curing agent. preferable.

The content of component (B) is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less when the non-volatile component in the resin composition is 100% by mass. The lower limit is not particularly limited, but 0.1% by mass or more is preferable.

<(C) Thermoplastic resin>
The resin composition contains (C) a thermoplastic resin. By containing the component (C), the elastic modulus can be lowered and the warpage can be reduced.

Examples of thermoplastic resins include phenoxy resins, acrylic resins, polyvinyl acetal resins, butyral resins, polyimide resins, polyamideimide resins, polyethersulfone resins, and polysulfone resins. , and acrylic resins. The thermoplastic resin may be used singly or in combination of two or more.

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

Examples of phenoxy resins include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, and terpene. and a phenoxy resin having one or more skeletons selected from the group consisting of a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. A phenoxy resin may be used individually by 1 type, or 2 or more types may be used together. Specific examples of phenoxy resins include Mitsubishi Chemical's "1256" and "4250" (both phenoxy resins containing bisphenol A skeleton), "YX8100" (phenoxy resin containing bisphenol S skeleton), and "YX6954" (bisphenolacetophenone). skeleton-containing phenoxy resin), and in addition, "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; ”, “YL6794”, “YL7213”, “YL7290” and “YL7482”.

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

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

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

As the epoxy group-containing acrylic resin having a glass transition temperature of 25°C or less, an epoxy group-containing acrylic acid ester copolymer resin having a glass transition temperature of 25°C or less is preferable. -80H" (epoxy group-containing acrylic ester copolymer resin (number average molecular weight Mn: 350000 g / mol, epoxy value 0.07 eq / kg, glass transition temperature 11 ° C.)), Nagase ChemteX Co., Ltd. "SG-P3" (epoxy group-containing acrylate copolymer resin (number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg, glass transition temperature 12°C)).

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

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

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

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

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

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

The content (c1) of the component (C) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more preferably 0% by mass, when the non-volatile component in the resin composition is 100% by mass. .3% by mass or more. Also, it is preferably 10% by mass or less, more preferably 9% by mass or less, and even more preferably 8% by mass or less. By setting the content of component (C) within this range, the viscosity of the resin composition becomes appropriate, and a resin composition layer having uniform thickness and bulk properties can be formed.

When the content mass of the resin component in the resin composition is a1 and the content mass of the component (C) is c1, (c1/a1) × 100 is preferably 35 or more. It is preferable to adjust the amount, more preferably 45 or more, more preferably 55 or more, 65 or more, or 70 or more. The upper limit is preferably 80 or less, more preferably 78 or less, even more preferably 77 or less. By adjusting the content of the component (C) within such a range, the elastic modulus at 23° C. of a cured product obtained by thermally curing the resin composition can easily be 7 GPa or more and 18 GPa or less. As a result, it is possible to obtain a cured product that is excellent in flame retardancy, suppresses the amount of warpage, can improve the relative magnetic permeability in the frequency range of 10 to 200 MHz, and can usually reduce the magnetic loss. be done. Furthermore, the adhesive film obtained using the resin composition has excellent lamination properties.
Here, the term "resin component" refers to non-volatile components constituting the resin composition, excluding components (D) and (E).

<(D) Magnetic filler>
The resin composition contains (D) a magnetic filler. The material of the magnetic filler is not particularly limited. 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 alloy powder, Alternatively, Fe alloys such as Fe—Ni—Co alloy powder, amorphous alloys such as Fe-based amorphous, Co-based amorphous, Mg—Zn ferrite, Mn—Zn ferrite, Mn—Mg ferrite, Cu—Zn based Spinel ferrites such as ferrite, Mg-Mn-Sr ferrite, Ni-Zn ferrite, Ba-Zn ferrite, Ba-Mg ferrite, Ba-Ni ferrite, Ba-Co ferrite, Ba-Ni- Examples include hexagonal ferrites such as Co-based ferrites and garnet-type ferrites such as Y-based ferrites. Among them, the component (D) includes 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 powders, are preferred.

A commercially available magnetic filler can be used as the magnetic filler. Specific examples of commercially available magnetic fillers that can be used include “PST-S” manufactured by Sanyo Special Steel Co., Ltd., “AW2-08” manufactured by Epson Atmix, “AW2-08PF20F”, “AW2-08PF10F”, “AW2- 08PF3F", "Fe-3.5Si-4.5CrPF20F", "Fe-50NiPF20F", "Fe-80Ni-4MoPF20F", JFE Chemical "LD-M", "LD-MH", "KNI-106" , "KNI-106GSM", "KNI-106GS", "KNI-109", "KNI-109GSM", "KNI-109GS", manufactured by Toda Kogyo "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 Japan Heavy Chemical Industry Co., Ltd., “Nanotek” manufactured by CIK Nanotech, “JEMK-S” manufactured by Kinseimatec, “JEMK-H” manufactured by Kinseimatek, “Yttrium iron oxide” manufactured by ALDRICH, etc. mentioned. A magnetic filler may be used individually by 1 type, or may use 2 or more types together.

Component (D) is preferably spherical. The value obtained by dividing the length of the long side of the powder of component (D) by the length of the short side (aspect ratio) is preferably 2 or less, more preferably 1.5 or less, and still more preferably 1.2 or less. is. In general, magnetic fillers having a flat shape rather than a spherical shape are more likely to improve the relative magnetic permeability. However, in order to achieve a predetermined elastic modulus by combining the components (A) to (C), it is easier to obtain a resin composition having desired properties by using the spherical component (D). can be done.

The average particle diameter of component (D) is preferably 0.01 μm or more, more preferably 0.5 μm or more, and still more preferably 1 μm or more. Also, it is preferably 8 μm or less, more preferably 5 μm or less, still more preferably 4 μm or less. The average particle size of component (D) can be measured by the same method as for the average particle size of component (E), which will be described later.

When a magnetic filler with an average particle size of 0.01 μm or more and 8 μm or less is used as component (D), when the frequency is 0 to 10 MHz, the relative magnetic permeability is higher than that when a magnetic filler with an average particle size of more than 25 μm is used. slightly inferior. However, even if the frequency exceeds 10 MHz, the relative magnetic permeability does not decrease rapidly, and a high relative magnetic permeability can be maintained in the range of 0 to 200 MHz. That is, magnetic losses are generally reduced while maintaining a high relative permeability over a wide range of 0 to 200 MHz, particularly 10 MHz to 200 MHz.

From the viewpoint of improving the relative magnetic permeability and flame retardancy, the content (% by volume) of component (D) is preferably 10% by volume or more, more preferably 10% by volume when the non-volatile component in the resin composition is 100% by volume. is 20% by volume or more, more preferably 30% by volume or more. Also, it is preferably 85% by volume or less, more preferably 75% by volume or less, and even more preferably 65% by volume or less.

The content of component (D) (% by mass: d1) is preferably 75% by mass or more when the non-volatile component in the resin composition is 100% by mass, from the viewpoint of improving the relative magnetic permeability and flame retardancy. More preferably 76% by mass or more, still more preferably 77% by mass or more. Also, it is preferably less than 95% by mass, more preferably 94% by mass or less, and even more preferably 93% by mass or less.

When an active ester curing agent is used as component (B) and/or when an acrylic resin is used as component (C), the compatibility of components (A) to (C) may be low. Therefore, the resin composition may form a sea-island structure consisting of a matrix phase (sea) and dispersed phases (islands), and component (D) may be unevenly distributed on the matrix phase side. As a result, the relative magnetic permeability of the entire cured product of the resin composition is improved. In this case, the matrix phase is preferably a mixture of components (A) and (B), and the dispersed phase is preferably component (C).

The composition of the resin composition containing the components (A) to (D) is adjusted so that the elastic modulus at 23 ° C. of the thermoset cured product is 7 GPa or more and 18 GPa or less, so that the frequency is 10 MHz or more. The relative magnetic permeability can be 5 or more at 200 MHz, especially when the frequency is 10 MHz to 100 MHz, and the magnetic loss can be usually 0.05 or less when the frequency is 10 MHz to 100 MHz.

<(E) Inorganic filler other than magnetic filler>
In one embodiment, the resin composition may contain (E) an inorganic filler other than the magnetic filler. By containing the component (E), magnetic loss can be reduced, thermal expansion of the magnetic layer can be suppressed, and reliability can be improved.

The material of component (E) is not particularly limited as long as it is an inorganic compound. Examples include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydro talcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, Examples include bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. As silica, spherical silica is preferable. (E) component may be used individually by 1 type, and may be used in combination of 2 or more type.

The average particle diameter of the inorganic filler is preferably 0.01 μm in order to improve the fluidity and moldability of the resin composition, and to improve the relative magnetic permeability and magnetic loss and the initial resistance value when cured. Above, more preferably 0.05 μm or more, still more preferably 0.1 μm or more and 0.3 μm or more. Also, it is preferably 5 μm or less, more preferably 2.5 μm or less, still more preferably 1.5 μm or less, and 1 μm or less.

The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis using a laser diffraction/scattering particle size distribution analyzer, and the median diameter thereof can be used as the average particle size for measurement. As a measurement sample, an inorganic filler dispersed in methyl ethyl ketone by ultrasonic waves can be preferably used. As the laser diffraction scattering type particle size distribution analyzer, Horiba's "LA-500", Shimadzu Corporation's "SALD-2200" and the like can be used.

Inorganic fillers include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, and alkoxysilanes, from the viewpoint of improving moisture resistance and dispersibility. , an organosilazane compound, and a titanate-based coupling agent. Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., Shin-Etsu Chemical Industry Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "SZ-31" ( Hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd. "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM-4803" (long-chain epoxy type silane coupling agent), Shin-Etsu Chemical Co., Ltd. "KBM- 7103” (3,3,3-trifluoropropyltrimethoxysilane).

From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment with the surface treatment agent is 0.2 parts by mass to 5 parts by mass of the surface treatment agent with respect to 100 parts by mass of the inorganic filler. preferably 0.2 to 3 parts by mass, more preferably 0.3 to 2 parts by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and more preferably 0.2 mg/m ² from the viewpoint of improving the dispersibility of the inorganic filler. The above is more preferable. On the other hand, from the viewpoint of suppressing the melt viscosity of the resin varnish and the melt viscosity in the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and further preferably 0.5 mg/m ² or less. preferable.

The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (eg, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent, and ultrasonic cleaning is performed at 25° C. for 5 minutes. After removing the supernatant liquid and drying the solid content, a carbon analyzer can be used to measure the amount of carbon per unit surface area of the inorganic filler. As a carbon analyzer, "EMIA-320V" manufactured by Horiba Ltd. can be used.

When the resin composition contains the component (E), the content of the component (E) (% by mass: e1) is a viewpoint of enhancing the reliability of insulation and flame retardancy when the resin composition is cured. Therefore, when the non-volatile component in the resin composition is 100% by mass, it is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more. Also, it is preferably 25% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less.

When the resin composition contains component (E), the content (% by volume) of component (E) is preferably 1% by volume or more, more preferably 3% by volume or more, and still more preferably 5% by volume or more. . Also, the upper limit is preferably 30% by volume or less, more preferably 25% by volume or less, and even more preferably 20% by volume or less.

When the resin composition contains the component (E), when the content of the component (D) in the resin composition is d1 and the content of the component (E) is e1, the resin composition is treated as a cured product. e1/d1 is preferably 0 from the viewpoint of improving the relative magnetic permeability and magnetic loss in the frequency range of 10 to 200 MHz, suppressing thermal expansion of the magnetic layer, and improving reliability. 0.02 or more, more preferably 0.025 or more, and still more preferably 0.03 or more. Also, the upper limit is preferably 0.19 or less, more preferably 0.185 or less, and more preferably 0.18 or less.

The average particle size of component (E) is preferably smaller than the average particle size of component (D). If the ratio of the content of the component (D) and the component (E) is as described above, and the average particle size of the component (E) is smaller than the average particle size of the component (D), the magnetic filler particles are surrounded. Thus, the inorganic filler can be effectively arranged. As a result, the magnetic filler particles can be prevented from aggregating and coming into contact with each other, and the magnetic filler particles can be spaced apart from each other. can be realized.

<(F) Curing accelerator>
In one embodiment, the resin composition may contain (F) a curing accelerator. Examples of curing accelerators include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. Curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are preferred, and imidazole-based curing accelerators are more preferred. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

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

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

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

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

Guanidine curing accelerators include, for example, dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, Tetramethylguanidine, Pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0] Dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 -allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide and the like, with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

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

When the resin composition contains a curing accelerator, the content of the curing accelerator is preferably 0.001% by mass to 1% by mass when the nonvolatile component in the resin composition is 100% by mass, and 0.001 % to 0.1% by mass is more preferred, and 0.005% to 0.05% by mass is even more preferred.

<(G) Flame Retardant>
In one embodiment, the resin composition may contain (G) a flame retardant. Examples of flame retardants include organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, and metal hydroxides. A flame retardant may be used individually by 1 type, or may use 2 or more types together.

As the flame retardant, a commercially available product may be used, and examples thereof include “HCA-HQ” manufactured by Sanko Co., Ltd., and “PX-200” manufactured by Daihachi Chemical Industry Co., Ltd. A flame retardant may be used individually by 1 type, or may use 2 or more types together.

When the resin composition contains a flame retardant, the content of the flame retardant is preferably in the range of 0.5% by mass to 10% by mass when the non-volatile component in the resin composition is 100% by mass. It is more preferably in the range of 1% by mass to 9% by mass, and even more preferably in the range of 1.5% by mass to 8% by mass.

<(H) Organic filler>
In one embodiment, the resin composition may contain (H) an organic filler. Examples of organic fillers include rubber particles. As the rubber particles which are organic fillers, for example, rubber particles which are insoluble in an organic solvent to be described later and which are incompatible with components (A) to (C) are used. Such rubber particles are generally prepared by increasing the molecular weight of the components of the rubber particles to such an extent that they do not dissolve in organic solvents and resins, and forming particles.

Examples of rubber particles that are organic fillers include core-shell rubber particles, crosslinked acrylonitrile-butadiene rubber particles, crosslinked styrene-butadiene rubber particles, and acrylic rubber particles. The core-shell type rubber particles are rubber particles having a core layer and a shell layer, and have, for example, a two-layer structure in which the outer shell layer is composed of a glassy polymer and the inner core layer is composed of a rubbery polymer, or Examples thereof include rubber particles having a three-layer structure in which an outer shell layer is composed of a glassy polymer, an intermediate layer is composed of a rubbery polymer, and an inner core layer is composed of a glassy polymer. The glass-like polymer layer is made of, for example, methyl methacrylate polymer, and the rubber-like polymer layer is made of, for example, butyl acrylate polymer (butyl rubber). Examples of rubber particles that can be used include "Staphyloid AC3816N" manufactured by Ganz. One type of rubber particles may be used alone, or two or more types may be used in combination.

The average particle size of the rubber particles as the organic filler is preferably in the range of 0.005 μm to 1 μm, more preferably in the range of 0.2 μm to 0.6 μm. The average particle size of rubber particles can be measured using a dynamic light scattering method. For example, rubber particles are uniformly dispersed in an appropriate organic solvent using ultrasonic waves or the like, and a concentrated particle size analyzer ("FPAR-1000" manufactured by Otsuka Electronics Co., Ltd.) is used to create a particle size distribution of the rubber particles on a mass basis. , the median diameter of which can be measured as the average particle diameter.

When the resin composition contains an organic filler, the content of the organic filler is preferably 0.1 to 20% by mass, and 0.2 to 10% by mass when the non-volatile component in the resin composition is 100% by mass. % by mass is more preferred, and 0.3 to 5% by mass, or even more preferably 0.5 to 3% by mass.

<(I) Optional Additives>
In one embodiment, the resin composition may further contain other additives as necessary, and examples of such other additives include organic copper compounds, organic zinc compounds, and organic cobalt compounds. and resin additives such as thickeners, antifoaming agents, leveling agents, adhesion imparting agents, and coloring agents.

<Physical properties and applications of the resin composition>
A cured product obtained by thermosetting the resin composition of the present embodiment (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) has an elastic modulus at 23° C. of 7 GPa or more, preferably 7.5 GPa or more, more preferably 7.5 GPa or more. 8 GPa or more. Also, the upper limit is 18 GPa or less, preferably 17 GPa or less, and more preferably 16 GPa or less. By setting the elastic modulus within such a range, the flame resistance is excellent, the amount of warpage is suppressed, and in particular, the relative magnetic permeability can be improved in the frequency range of 10 to 200 MHz, and the magnetic loss can be reduced. can get things. Furthermore, the adhesive film obtained using the resin composition has excellent lamination properties. The elastic modulus can be set within the above range by adjusting components (A) to (D). The elastic modulus can be measured according to the method described in <Measurement of Elastic Modulus> below.

A cured product obtained by thermosetting the resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) exhibits a characteristic of high relative magnetic permeability at a frequency of 10 MHz. The relative magnetic permeability at a frequency of 10 MHz is preferably 5 or higher, more preferably 6 or higher, and even more preferably 7 or higher. Also, it is preferably 20 or less, more preferably 18 or less, and still more preferably 15 or less. The relative permeability can be measured according to the method described in <Measurement of Relative Permeability and Magnetic Loss> below.

A cured product obtained by heat-curing the resin composition (for example, a cured product obtained by heat-curing at 180° C. for 90 minutes) exhibits a characteristic of high relative magnetic permeability at a frequency of 100 MHz. The relative permeability at a frequency of 100 MHz is preferably 5 or higher, more preferably 6 or higher, and even more preferably 7 or higher. Also, it is preferably 20 or less, more preferably 18 or less, and still more preferably 15 or less.

A cured product obtained by thermosetting the resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) may have a low relative magnetic permeability at a frequency of 1 GHz. The relative magnetic permeability at a frequency of 1 GHz is preferably 4 or higher, more preferably 5 or higher, and even more preferably 6 or higher. Also, it is preferably 16 or less, more preferably 15 or less, still more preferably 14 or less.

A cured product obtained by thermosetting the resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) may have a low relative magnetic permeability at a frequency of 3 GHz. The relative magnetic permeability at a frequency of 3 GHz is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. Also, it is preferably 10 or less, more preferably 9 or less, and still more preferably 8 or less.

A cured product obtained by thermosetting the resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) exhibits a characteristic of low magnetic loss at a frequency of 10 MHz. Magnetic loss at a frequency of 10 MHz is preferably 0.05 or less, more preferably 0.04 or less, and even more preferably 0.03 or less. Although the lower limit is not particularly limited, it may be 0.0001 or more. The magnetic loss can be measured according to the method described in <Measurement of Relative Permeability and Magnetic Loss> below.

A cured product obtained by thermosetting the resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) exhibits a characteristic of low magnetic loss at a frequency of 100 MHz. Magnetic loss at a frequency of 100 MHz is preferably 0.05 or less, more preferably 0.04 or less, and even more preferably 0.03 or less. Although the lower limit is not particularly limited, it may be 0.0001 or more.

Since the resin composition contains the component (C), a cured product obtained by heat-curing the resin composition (for example, a cured product obtained by heat-curing at 180° C. for 90 minutes) exhibits a characteristic that the amount of warpage is reduced. The amount of warpage is preferably 10 mm or less, more preferably 9 mm or less, still more preferably 8 mm or less. Although the upper limit is not particularly limited, it may be 0.1 mm or more. The amount of warpage can be measured according to the method described in <Measurement of amount of warp> described later.

A cured product obtained by heat-curing the resin composition (for example, a cured product obtained by heat-curing at 180° C. for 90 minutes) exhibits excellent flame retardancy. For flame retardancy, the UL94 vertical flame resistance test is performed five times, and it is preferable that all five samples remain unburned after 10 seconds of indirect flame. Evaluation of flame retardancy can be measured according to the method described in <Evaluation of Flame Retardancy> below.

The resin composition of the present embodiment has excellent fluidity during formation of the magnetic layer, and excellent sealing properties of the wiring layer when formed into the magnetic layer (cured product). Further, if a magnetic layer is formed using the resin composition of the present invention, it is possible to improve the relative magnetic permeability and reduce the magnetic loss in the frequency range of 10 MHz to 200 MHz, particularly in the frequency range of 10 MHz to 100 MHz. can. In addition, the magnetic layer (cured product) obtained by thermally curing the resin composition of the present embodiment also has excellent insulating properties.

Therefore, the resin composition of the present embodiment can be applied to a wiring board having an inductor element having a so-called film structure in which a coil is built into the thickness of a magnetic layer (a magnetic body part in which a plurality of magnetic layers are laminated). It can be suitably used as a layer material, and can be more suitably used particularly when the frequency at which the inductor element functions is 10 MHz to 200 MHz.

[Cured product]
The cured product of the present invention is obtained by thermosetting the resin composition of the present invention. The cured product of the present invention has an elastic modulus of 7 GPa or more and 18 GPa or less at 23° C. when heat-cured at 180° C. for 90 minutes, and the preferred range is as described above.

The thermosetting conditions for the resin composition are not particularly limited, and for example, the conditions for the thermosetting step in the step of forming the first magnetic layer, which will be described later, may be used. In addition, preheating may be performed at a temperature lower than the heat curing temperature before heat curing.

The thickness of the cured product varies depending on the application, but when used as a magnetic layer of a wiring board with a built-in inductor element, the thickness is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and even more preferably 40 μm or less. be. Although the lower limit of the thickness of the cured product varies depending on the application, it is usually 10 μm or more when used as a magnetic layer of a wiring board with a built-in inductor element.

[Adhesive film]
The adhesive film of the present invention comprises a support and a resin composition layer formed of the resin composition of the present invention provided on the support.

The thickness of the resin composition layer is not particularly limited. The resin composition layer preferably has a thickness of 0.5 μm to 80 μm, more preferably 10 μm to 60 μm.

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

When a film made of a plastic material is used as the support, it is preferable to use a plastic material with a high glass transition temperature (Tg). Examples of plastic materials having a glass transition temperature of 100° C. or higher include polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) and polyethylene naphthalate (hereinafter sometimes abbreviated as “PEN”). Polyester, polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. is mentioned. Among them, polyethylene terephthalate, polyethylene naphthalate, and polyimide are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

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

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

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. The release agent used in the release layer of the release layer-attached support includes, for example, one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. . As the support with a release layer, a commercially available product may be used, for example, "SK-1", " AL-5", "AL-7", Toray's "Lumirror T60", Teijin's "Purex", and Unitika's "Unipeel".

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

The resin composition used in the resin composition layer is obtained by appropriately mixing the above-described components and, if necessary, kneading means (three rolls, ball mill, bead mill, sand mill, etc.) or stirring means (super mixer, planetar). It can be prepared by kneading or mixing with a Lee mixer, etc.).

The method for producing an adhesive film having a resin composition layer is not particularly limited. For example, a resin varnish is prepared by dissolving a resin composition in an organic solvent, and this resin varnish is applied to a support using a die coater or the like. and drying the coating film of the applied resin varnish.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate; and carbitols such as cellosolve and butyl carbitol. aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. An organic solvent may be used individually by 1 type, or may use 2 or more types together.

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. Depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% by mass to 60% by mass of the organic solvent, for example, by drying at 80 ° C. to 150 ° C. for about 3 minutes to 15 minutes. , a resin composition layer can be formed.

In the adhesive film, a protective film conforming to the support can be further laminated on the surface of the resin composition layer that is not bonded to the support (that is, the surface opposite to the support). Although the thickness of the protective film is not particularly limited, it is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to prevent dust from adhering to the surface of the resin composition layer and scratches on the surface of the resin composition layer. The adhesive film can be wound into a roll and stored. When the adhesive film has a protective film, it can be used by peeling off the protective film.

The adhesive film of the present invention is composed of the component (A) so that the elastic modulus at 23° C. of a cured product obtained by thermosetting a resin composition (for example, a cured product obtained by thermosetting at 180° C. for 90 minutes) is 7 GPa or more and 18 GPa or less. Since the content of the component (D) is adjusted, it exhibits excellent lamination properties. Even if the wiring board is laminated with the adhesive film, there are usually no voids in the circuit portion of the wiring board, and the resin composition derived from the adhesive film is sufficiently flowing.

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

The wiring board has a magnetic layer that is a cured body of a resin composition (resin composition layer) and a conductive structure having at least a portion embedded in the magnetic layer. It includes an inductor element extending through the thickness of the magnetic layer and formed by a portion 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 this embodiment can function is 10 MHz to 200 MHz. In addition, the inductor element included in the wiring board of the present embodiment is assumed to be a power supply system.

As shown in FIGS. 1 and 2, wiring board 10 is a buildup wiring board having a buildup magnetic layer. Wiring board 10 includes core substrate 20 . The core substrate 20 has a first major surface 20a and a second major surface 20b opposite the first major surface 20a. Core substrate 20 is an insulating substrate. The core substrate 20 may be an inner-layer circuit board in which wiring and the like are formed within its thickness.

Examples of materials for the core substrate 20 include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates.

Core substrate 20 has first wiring layer 42 provided on first main surface 20a and external terminals 24 provided on 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 forming the coil-shaped 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 terminals 24 can be configured as part of a wiring layer provided on the second main surface 20b.

Conductive materials that can constitute the first wiring layer 42, the second wiring layer 44, the external terminals 24, and other wiring include, for example, gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, 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 terminals 24, and other wiring may be composed of a single metal or an alloy. alloys of two or more metals (eg, nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among them, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys can be used from the viewpoint of versatility, cost, ease of patterning, and the like. Chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloys are preferably used, and copper is even more preferred.

The first wiring layer 42, the second wiring layer 44, the external terminals 24, and other wiring may have a single-layer structure, but may be multiple layers in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. It may have a layered structure. When the first wiring layer 42, the second wiring layer 44, the external terminals 24, and other wiring have a multilayer structure, the layer in contact with the magnetic layer is a single metal layer of chromium, zinc, or titanium, or a nickel-chromium alloy. Layers are preferred.

The thicknesses of the first wiring layer 42, the second wiring layer 44, the external terminals 24, and other wirings are generally 3 μm to 35 μm, preferably 5 μm to 30 μm, depending on the desired multilayer printed wiring board design.

The thicknesses of the first wiring layer 42 and the external terminals 24 of the core base material 20 are not particularly limited. The thicknesses of the first wiring layer 42 and the external terminals 24 are preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, even more preferably 40 μm or less, and particularly preferably, from the viewpoint of thickness reduction. is 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. Although the lower limit of the thickness of the external terminal 24 is not particularly limited, it is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

Although the line (L)/space (S) ratio of the first wiring layer 42 and the external terminal 24 is not particularly limited, it is usually 900/900 μm or less from the viewpoint of obtaining a magnetic layer with excellent smoothness by reducing the unevenness of the surface. , preferably 700/700 μm or less, more preferably 500/500 μm or less, even more preferably 300/300 μm or less, and even more preferably 200/200 μm or less. Although the lower limit of the line/space ratio is not particularly limited, it is preferably 1/1 μm or more from the viewpoint of better embedding of the resin composition into the space.

As the core substrate 20, for example, a wiring board made by patterning a copper layer to form a wiring layer by using "R1515A" manufactured by Panasonic Corporation, which is a double-sided copper-clad laminate made of epoxy resin with a glass cloth substrate, is exemplified.

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

As shown in FIG. 3, the first wiring layer 42 includes a spiral wiring portion for forming the coil-shaped conductive structure 40 and a rectangular land 42a electrically connected to the through-hole wiring 22a. and In the illustrated example, the spiral wiring portion includes a bent portion that bends at right angles to the linear portion and a detour portion that detours around 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 that is wound counterclockwise from the center toward the outside.

On the side of the first main surface 20a of the core substrate 20 on which the first wiring layer 42 is provided, the first magnetic layer 32 is formed so as to cover 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 already-described adhesive film, it has excellent sealing properties for the first wiring layer 42 . Also, since the first magnetic layer 32 is formed using the adhesive film, the relative magnetic permeability is improved in the frequency range of 10 MHz to 200 MHz, and the magnetic loss is usually reduced.

A via hole 36 is provided in the first magnetic layer 32 so as to penetrate the first magnetic layer 32 in its thickness direction.

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 coil-shaped conductive structure 40 . In the illustrated example, the spiral wiring portion includes a linear portion and a bent portion that bends at right angles. 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 that is wound clockwise from the center toward the outside.

A via-hole wiring 36 a 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 an in-via-hole wiring 36a. . The other end on the outer peripheral side of the spiral wiring portion of the second wiring layer 44 is electrically connected to the land 42a of the first wiring layer 42 by the via-hole wiring 36a. Therefore, the other end on the outer peripheral side of the spiral wiring portion of the second wiring layer 44 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 includes a spiral wiring portion that is a portion of the first wiring layer 42, a spiral wiring portion that is a portion of the second wiring layer 44, and a spiral wiring portion of the first wiring layer 42. and the spiral wiring portion of the second wiring layer 44 are formed by the via-hole wiring 36a electrically connecting the wiring 36a.

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

Like the first magnetic layer 32, the second magnetic layer 34 is a layer derived from the adhesive film already described. The sealing property of the wiring layer 44 is excellent. Further, since the second magnetic layer 34 is formed using the adhesive film, the relative magnetic permeability is improved in the frequency range of 10 MHz to 200 MHz, and the magnetic loss is usually reduced.

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

In the present embodiment, an example in which the coil-shaped conductive structure 40 includes two wiring layers, the first wiring layer 42 and the second wiring layer 44, is described. The coil-shaped conductive structure 40 can also be configured by the build-up magnetic layer of . In this case, the spiral wiring part of the wiring layer (not shown) arranged to be sandwiched between the uppermost wiring layer and the lowermost wiring layer has one end on the uppermost layer side and is arranged in the immediate vicinity. is electrically connected to either one end of the spiral wiring part of the wiring layer that is electrically connected to the

According to the wiring board of the present embodiment, since the magnetic layer is formed of the adhesive film, the relative magnetic permeability and flame retardancy of the formed magnetic layer can be improved, and the amount of warpage can be reduced.

A method of manufacturing a wiring board with a built-in inductor element according to the first embodiment will be described below with reference to FIG.
The wiring board manufacturing method according to the present embodiment includes a magnetic portion including a first magnetic layer and a second magnetic layer, and a coil-shaped conductive structure having at least a portion embedded in the magnetic portion. A method for manufacturing a wiring board including an inductor element composed of a conductive structure and a part of a magnetic part, the adhesive film according to the present embodiment and a core substrate provided with a first wiring layer a step of laminating a resin composition layer of an adhesive film on a core substrate; a step of thermosetting the resin composition layer to form a first magnetic layer; and forming a via hole in the first magnetic layer. roughening the first magnetic layer in which the via hole is formed; forming a second wiring layer on the first magnetic layer; and electrically connecting the first wiring layer and the second wiring layer. A step of forming wiring in the via hole to be connected, further laminating the adhesive film according to the present embodiment on the first magnetic layer on which the second wiring layer and the wiring in the via hole are formed, and thermally curing to form the second magnetic layer. a coil-shaped conductive structure including a portion of the first wiring layer, a portion of the second wiring layer, and wiring in the via hole, and a coil-shaped conductive structure extending in the thickness direction of the magnetic portion; and forming an inductor element including a portion of the magnetic portion surrounded by.

First, the first wiring layer 42 provided on the first main surface 20a, the external terminal 24 provided on the second main surface 20b, the through holes 22, and the core base material (inner layer) provided with the wiring 22a in the through holes are provided. A circuit board) 20 and an adhesive film are prepared.

<Step of Forming First Magnetic Layer>
Next, the first magnetic layer 32 is formed. First, a lamination step is performed to laminate the resin composition layer of the adhesive film so as to be in contact with the first wiring layer 42 of the core substrate.

The conditions for the lamination step are not particularly limited, and the conditions used for forming a magnetic layer (build-up magnetic layer) using an adhesive film can be employed. For example, it can be carried out by pressing a heated metal plate such as a stainless steel end plate from the support side of the adhesive film. In this case, rather than 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 adhesive film can sufficiently follow the irregularities on the surface of the core substrate 20 . The pressing temperature is preferably in the range of 70° C. to 140° C., the pressing 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 pressing time is preferably 5 hours. It ranges from seconds to 3 minutes.

Moreover, the lamination step is preferably carried out under a reduced pressure of 20 mmHg (26.7 hPa) or less. The lamination process can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurized laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nikko Materials, and the like.

After completion of the lamination step, the adhesive film laminated to the core substrate 20 may be subjected to a smoothing step of heat and pressure treatment.

The smoothing step is generally performed by heating and pressurizing the adhesive film laminated to the core substrate 20 with a heated metal plate or metal roll under normal pressure (atmospheric pressure). As the conditions for the heating and pressurizing treatment, the same conditions as those for the lamination step can be used.

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

A step of peeling off the support originating from the adhesive film is performed at an arbitrary timing after the lamination step or the smoothing step. The step of peeling off the support can be mechanically carried out by, for example, a commercially available automatic peeling device.

Next, a thermosetting step is performed for thermosetting the resin composition layer laminated on the core substrate 20 to form a magnetic layer (build-up magnetic layer).

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

The conditions of the thermosetting step can be arbitrarily suitable conditions depending on the composition of the resin composition used for the resin composition layer. The conditions for the heat curing step are, for example, a curing temperature in the range of 120° C. to 240° C. (preferably 150° C. to 210° C., more preferably 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).

A step of preheating the resin composition layer at a temperature lower than the curing temperature may be performed before performing the thermosetting step. Prior to the implementation of the thermosetting step, the resin composition layer is heated for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes) may be preheated. Preheating is preferably performed under atmospheric pressure (normal pressure).

The first magnetic layer 32 provided on the core substrate 20 can be formed by the above steps. Further, the lamination step, the heat curing step, and the step of forming a wiring layer, which will be described later, are repeated one or more times on the core substrate 20 on which the magnetic layers are formed, thereby forming the second magnetic layer provided on the first magnetic layer 32 . The magnetic part 30 including the magnetic layer 34 and further laminated magnetic layers can be formed.

Further, the step of forming the first magnetic layer 32 on the core substrate 20 can also be performed using a general vacuum hot press. For example, it can be performed by pressing from the support side using a heated metal plate such as a SUS plate. Pressing conditions are such that the degree of pressure reduction is usually 1×10 ⁻² MPa or less, preferably 1×10 ⁻³ MPa or less. Heating and pressurization can be performed in one step, but from the viewpoint of controlling resin exudation, it is preferable to perform two or more steps with different pressing conditions. For example, the pressing conditions for the first step are a temperature of 70°C to 150°C and a pressure of 1 kgf/cm ² to 15 kgf/cm ² , and the pressing conditions for the second step are 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 duration of each step is preferably 30 to 120 minutes. Examples of commercially available vacuum hot press machines include "MNPC-V-750-5-200" manufactured by Meiki Seisakusho and "VH1-1603" manufactured by Kitagawa Seiki.

<Formation process of via hole>
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, laser, plasma, or the like, taking into consideration the characteristics of the first magnetic layer 32 . For example, if the protective film remains at this point, the via holes 36 can be formed by irradiating the first magnetic layer 32 with laser light through the protective film.

Laser light sources that can be used to form the via holes 36 include, for example, a carbon dioxide gas laser, a YAG laser, an excimer laser, and the like. Among them, a carbon dioxide laser is preferable from the viewpoint of processing speed and cost.

Formation of the via hole 36 can be performed 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 processing machine manufactured by Matsushita Welding Systems.

<Roughening process>
Next, a roughening process is performed to roughen the first magnetic layer 32 in which the via holes 36 are formed. The procedure and conditions of the roughening step are not particularly limited, and known procedures and conditions that are commonly used in the manufacturing method of multilayer printed wiring boards can be employed. As the roughening process, for example, the first magnetic layer 32 can be roughened by performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid in this order.

The swelling liquid that can be used in the roughening step is not particularly limited, but includes alkaline solutions, surfactant solutions, etc., preferably alkaline solutions. A sodium hydroxide solution and a potassium hydroxide solution are more preferable as the alkaline solution that is the swelling liquid. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan.

The swelling treatment with the swelling liquid is not particularly limited, but can be performed, for example, by immersing the core substrate 20 provided with the first magnetic layer 32 in the swelling liquid at 30° C. to 90° C. for 1 minute to 20 minutes. . From the viewpoint of suppressing the swelling of the resin forming the first magnetic layer 32 to an appropriate level, it is preferable to immerse the first magnetic layer 32 in the swelling liquid at 40.degree. C. to 80.degree. C. for 5 to 15 minutes.

The oxidizing agent that can be used for the roughening treatment with an oxidizing agent is not particularly limited, but examples thereof include an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the first magnetic layer 32 in an oxidizing agent solution heated to 60° C. to 80° C. for 10 to 30 minutes. Further, the permanganate concentration in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact P" and "Dosing Solution Security P" manufactured by Atotech Japan.

As a neutralizing solution that can be used for the neutralization treatment, an acidic aqueous solution is preferable, and commercially available products include, for example, "Reduction Solution Security P" manufactured by Atotech Japan. The neutralization treatment with the neutralizing solution can be carried out by immersing the treated surface roughened with the oxidant solution in the neutralizing solution at 30° C. to 80° C. for 5 to 30 minutes. From the viewpoint of workability, etc., it is preferable to immerse the first magnetic layer 32, which has been roughened with an oxidant solution, in a neutralizing solution at 40.degree. C. to 70.degree. C. for 5 to 20 minutes.

The roughening process described above may also serve as a so-called desmear process for removing smear from the via holes 36 formed in the first magnetic layer 32 .

In addition to the roughening process, the via hole 36 may be subjected to a desmear process. This desmear process may be a wet desmear process or a dry desmear process.

Specific steps of the desmear step are not particularly limited, and for example, known steps and conditions that are commonly used for forming insulating layers of multilayer printed wiring boards can be employed. Examples of the dry desmear process include plasma treatment, and examples of the wet desmear process include swelling treatment with a swelling liquid similar to the roughening process, treatment with an oxidizing agent, and treatment with a neutralizing liquid in this order. method of doing so.

<Formation of Second Wiring Layer>
Next, the second wiring layer 44 is formed on the first magnetic layer 32 subjected to the roughening process (and the desmear process).

The second wiring layer 44 can be formed by plating. The second wiring layer 44 is formed by a conventionally known technique such as an electroless plating process, a mask pattern forming process, an electroplating process, a semi-additive process including a flash etching process, a full-additive process, or the like, thereby forming a desired wiring. It can be formed as a wiring layer including 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. Next, as shown in FIG.

When the first magnetic layer 32 is a buildup magnetic layer and the second wiring layer 44 is a buildup wiring layer as a buildup layer, the wiring board of the present embodiment further requires one or more buildup layers. In this case, the above-described series of steps 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 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 via-hole wiring 36a are formed. The second magnetic layer 34 may be formed by using the same materials and by the same steps as the steps of forming the first magnetic layer 32 including the adhesive film laminating step, smoothing step, and heat curing step already described.

Through the above steps, the coil-shaped conductive structure 40 having at least a portion embedded in the magnetic portion 30 is formed, and a portion of the first wiring layer 42, a portion of the second wiring layer 44, and the wiring 36a in the via hole are formed. and a portion of the magnetic portion 30 extending in the thickness direction of the magnetic portion 30 and surrounded by the coil-shaped conductive structure 40. can be manufactured.

(Second embodiment)
A configuration example of a wiring board with a built-in inductor element according to the second embodiment will be described with reference to FIG. 4(h). Components similar to those of the first embodiment are denoted by the same reference numerals, and redundant description may be omitted.

As shown in FIG. 4(h), wiring board 11 has a magnetic layer that is a cured body of a resin composition (resin composition layer) and a conductive structure at least a portion of which is embedded in the magnetic layer. and an inductor element formed by a portion of the magnetic layer extending through the thickness of the magnetic layer and surrounded by the conductive structure. Wiring board 11 is a buildup wiring board having a buildup magnetic layer. Wiring board 11 differs from wiring board 10 of the first embodiment in that it does not have a core base material.

It is assumed that the frequencies at which the inductor elements provided on the wiring board 11 can function are 10 MHz to 200 MHz. Also, the inductor element provided on 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 contain a plurality of wirings. In the illustrated example, only the wiring forming the coil-shaped conductive structure 40 of the inductor element is shown. The first wiring layer 42, the second wiring layer 44, the external terminals 24, and other wiring are the same as the first wiring layer 42, the second wiring layer 44, the external terminals 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. Also, 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 or a multi-layer structure in which two or more single metal layers or alloy layers made of different kinds of metals or alloys are laminated. When the 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 the magnetic section 30 which can be viewed as an integrated 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 already-described adhesive film, and the resin composition layer of the adhesive film has excellent fluidity when the magnetic layer is formed. Are better. Further, since the third magnetic layer 38 is formed using the adhesive film, the relative magnetic permeability is improved in the frequency range of 10 MHz to 200 MHz, and the magnetic loss is usually reduced.

A via-hole wiring 36 a 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 to each other by the in-via-hole wiring 36a and the like.

In the present embodiment, an example in which the coil-shaped conductive structure 40 includes three wiring layers of the first wiring layer 42, the second wiring layer 44, and the third wiring layer 46 has been described. The coil-shaped conductive structure 40 can also be configured by wiring layers (and four or more build-up magnetic layers). In this case, the spiral wiring part of the wiring layer (not shown) arranged to be sandwiched between the uppermost wiring layer and the lowermost wiring layer has one end on the uppermost layer side and is arranged in the immediate vicinity. is electrically connected to either one end of the spiral wiring part of the wiring layer that is electrically connected to the

According to the wiring board of the present embodiment, since the magnetic layer is formed of the adhesive film, the relative magnetic permeability and flame retardancy of the formed magnetic layer can be improved, and the amount of warpage can be reduced.

A method of manufacturing a wiring board with a built-in inductor element according to the second embodiment will be described below with reference to FIG. Descriptions of portions that overlap with the first embodiment will be omitted as appropriate.
The wiring board manufacturing method according to the present embodiment includes:
(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 an adhesive film on the substrate 50 with a carrier and metal layer, and thermally curing the resin composition layer to form the first magnetic layer 32;
(3) forming the first wiring layer 42 on the first magnetic layer 32;
(4) a step of laminating a resin composition layer of an adhesive film on the first wiring layer 42 and the first magnetic layer 32 and thermally curing the resin composition layer to form the second magnetic layer 34;
(5) forming via holes 36 in the second magnetic layer 34 and roughening the second magnetic layer 34 in which the via holes 36 are formed;
(6) forming a second wiring layer 44 on the second magnetic layer 34;
(7) a step of laminating a resin composition layer of an adhesive film on the second wiring layer 44 and the second magnetic layer 34 and thermally curing the resin composition layer to form the third magnetic layer 38;
(8) removing the carrier-attached metal layer-attached substrate 50;
(9) forming a via hole 36 in the third magnetic layer 38 and roughening the third magnetic layer 38 in which the via hole 36 is formed;
(10) forming via holes 36 in the first magnetic layer 32 and roughening the first magnetic layer 32 in which the via holes 36 are formed;
(11) forming the third wiring layer 46 on the third magnetic layer 38; and (12) forming the external terminal 24 on the first magnetic layer 32.

Step (9) and step (10) may be performed in a different order, or may be performed simultaneously. Moreover, the step (11) and the step (12) may be performed in a different order, or may be performed at the same time.

<Step (1)>
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 with a carrier 52 provided on at least one surface of the base material 51 . As an example is shown in FIG. 4( a ), a substrate 50 with a metal layer with a carrier is usually provided with a substrate 51 and a metal layer 52 with a carrier on at least one surface of the substrate 51 . From the viewpoint of improving the workability of step (8), which will be described later, the carrier-attached metal layer 52 preferably has a configuration in which the first metal layer 521 and the second metal layer 522 are provided in this order from the substrate 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 copper foil with a carrier and metal foil with a peelable support. A commercially available product can be used as the base material 50 with a carrier-attached metal layer. Examples of commercially available products include MT-EX manufactured by Mitsui Kinzoku Co., Ltd., and the like.

<Step (2)>
In the step (2), as an example is shown in FIG. 4B, the resin composition layer of the adhesive film is laminated on the substrate 50 with the carrier-attached metal layer, and the resin composition layer is thermally cured to form the first magnetic layer. This is the step of forming the layer 32 .

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

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

<Step (3)>
Step (3) is a step of forming the first wiring layer 42 on the first magnetic layer 32, as shown in FIG. 4(c). The first wiring layer 42 can be formed by plating. The first wiring layer 42 can be formed by a method similar to that for forming the second wiring layer 44 in the first embodiment. Also, the first wiring layer 42 can use the same conductor material as the first wiring layer in the first embodiment.

<Step (4)>
In step (4), as an example is shown in FIG. 4D, a resin composition layer of an adhesive film is laminated on the first wiring layer 42 and the first magnetic layer 32, and the resin composition layer is heat-cured. Then, the second magnetic layer 34 is formed.

The second magnetic layer 34 can be formed by the same method as in step (2) described above. The adhesive film forming the second magnetic layer 34 may be the same as the adhesive film used to form the first magnetic layer 32, or may be different.

<Step (5)>
Step (5) is a step of forming via holes 36 in the second magnetic layer 34 and roughening the second magnetic layer 34 in which the via holes 36 are formed, as shown in an example in FIG. be. A via-hole wiring 36 a 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 process in the first embodiment. Further, the roughening treatment can be performed by the same method as the roughening process performed on the first magnetic layer in the first embodiment.

<Step (6)>
Step (6) is a step of forming a second wiring layer 44 on the second magnetic layer 34, as shown in FIG. 4(e). Specifically, 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 a method similar to that for forming the second wiring layer 44 in the first embodiment. Also, the second wiring layer 44 can use the same conductor material as the second wiring layer in the first embodiment.

<Step (7)>
In step (7), as an example is shown in FIG. 4F, a resin composition layer of an adhesive film is laminated on the second wiring layer 44 and the second magnetic layer 34, and the resin composition layer is heat-cured. Then, the third magnetic layer 38 is formed.

The third magnetic layer 38 can be formed by the same method as in step (2) described above. The adhesive film forming the third magnetic layer 38 may be the same as the adhesive film used to form the first magnetic layer 32 and the second magnetic layer 34, or may be different.

<Step (8)>
Step (8) is a step of removing the carrier-attached metal layer-attached substrate 50, as an example is shown in FIG. 4(g). A method for removing the base material 50 with a carrier-attached metal layer is not particularly limited. In one preferred embodiment, the substrate 51 and the first metal layer 521 are separated at the interface between the first metal layer 521 and the second metal layer 522, and the second metal layer 522 is etched away with, for example, a copper chloride aqueous solution. If necessary, the carrier-attached metal layer-attached substrate 50 may be peeled off while the third magnetic layer 38 is protected with a protective film.

<Step (9)>
Step (9) is a step of forming via holes (not shown in FIG. 4) in the third magnetic layer 38 and roughening the third magnetic layer 38 in which the via holes are formed. An intra-via-hole wiring 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 . This via hole can be formed by the same method as the via hole formation process in the first embodiment. Further, the roughening treatment can be performed by the same method as the roughening process performed on the first magnetic layer in the first embodiment.

<Step (10)>
Step (10) is a step of forming via holes 36 in the first magnetic layer 32 and roughening the first magnetic layer 32 in which the via holes 36 are formed, as shown in an example in FIG. 4(h). be. Specifically, a via hole 36 is formed on the side of the first magnetic layer 32 from which the carrier-attached metal layer-attached substrate 50 has been removed, and the external terminal 24 is formed on the via hole 36 . A via-hole wiring 36 a 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 by the same method as the via hole formation process in the first embodiment. Further, the roughening treatment can be performed by the same method as the roughening process performed on the first magnetic layer in the first embodiment.

<Step (11)>
Step (11) is a step of forming a third wiring layer 46 on the third magnetic layer 38, as shown in FIG. 4(h). Specifically, after the via hole (not shown) formed in the third magnetic layer 38 is roughened, 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 can be formed using the same conductor material as the first and second wiring layers in the first embodiment. can be done.

<Step (12)>
Step (12) is a step of forming external terminals 24 on the first magnetic layer 32, as shown in FIG. 4(h). Specifically, after the via hole 36 formed in the first magnetic layer 32 is roughened, the external terminal 24 is connected onto the via hole 36 .

Through the above steps, it is possible to manufacture a wiring board that does not have a base material and that includes an inductor element. The inductor element includes a coil-shaped conductive structure 40 and a portion of the magnetic section 30 extending in the thickness direction of the magnetic section 30 and surrounded by the coil-shaped conductive structure 40 . The coil-shaped conductive structure 40 includes a portion of the first wiring layer 42, a portion of the second wiring layer 44, a portion of the third wiring layer 46, and an in-via-hole wiring 36a.

When the first magnetic layer 32 is a buildup magnetic layer and the second wiring layer 44 is a buildup wiring layer as a buildup layer, the wiring board of the present embodiment further requires one or more buildup layers. In this case, the above-described series of steps 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 adhesive film of the present invention, it is possible to improve the relative magnetic permeability at a frequency of 10 MHz to 200 MHz, and to form a magnetic layer with excellent flame retardancy and a reduced amount of warpage. It is possible to provide a wiring board in which a higher-performance low-frequency band inductor element including a core formed of a portion of a magnetic layer without a core structure is built in a simpler process.

The wiring board according to the present embodiment can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer substrate. Also, such a wiring board can be used as chip inductor components obtained by individualizing, and can also be used as a printed wiring board in which the chip inductor components are surface-mounted.
Moreover, using such a wiring board, various types of semiconductor devices can be manufactured. A semiconductor device containing such a wiring board can be suitably used for electrical appliances (eg, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (eg, motorcycles, automobiles, trains, ships, aircraft, etc.). .

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Example 1: Preparation of resin composition 1>
"ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) 7 parts by mass, "HP-4700" (naphthalene type tetrafunctional epoxy resin, manufactured by DIC Corporation) 7 parts by mass, "YX7553" (phenoxy resin, non-volatile content 30% by mass, manufactured by Mitsubishi Chemical Corporation) 35 parts by weight, "KS-1" (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) 30 parts by weight MEK 10 parts by weight, cyclohexanone 10 parts by weight , 40 parts by mass of ethanol, and 40 parts by mass of toluene with stirring. There, "LA-7054" (60% by mass of non-volatile content of triazine skeleton-containing phenolic curing agent, manufactured by DIC) 14 parts by mass, "2E4MZ" (curing accelerator, manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.1 parts by mass , Inorganic filler (silica obtained by treating “SO-C2” (silica, average particle size 0.5 μm, manufactured by Admatechs) with “KBM-573” (aminosilane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.)) 35 Parts by mass, 850 parts by mass of "AW2-08PF3F" (magnetic filler, Fe--Cr--Si alloy (amorphous), average particle size of 3.0 μm, manufactured by Epson Atmix) are mixed and dispersed uniformly with a high-speed rotating mixer. Then, resin composition 1 was prepared.

<Example 2: Preparation of resin composition 2>
"ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) 14 parts by mass, "HP-4700" (naphthalene type tetrafunctional epoxy resin, manufactured by DIC Corporation) 14 parts by mass, "YX7553" (phenoxy resin, nonvolatile content 30% by mass, manufactured by Mitsubishi Chemical Corporation) 35 parts by mass, "KS-1" (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) 23 parts by mass MEK 10 parts by mass, cyclohexanone 10 parts by mass , 30 parts by mass of ethanol, and 30 parts by mass of toluene with stirring. There, "LA-7054" (triazine skeleton-containing phenolic curing agent, non-volatile content 60% by mass, manufactured by DIC) 28 parts by mass, "2E4MZ" (curing accelerator, manufactured by Shikoku Kasei Kogyo Co., Ltd.) 0.1 parts by mass , Inorganic filler (silica obtained by treating “SO-C2” (silica, average particle size 0.5 μm, manufactured by Admatechs) with “KBM-573” (aminosilane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.)) 35 Parts by mass, 1010 parts by mass of "AW2-08PF3F" (magnetic filler, Fe--Cr--Si alloy (amorphous), average particle size of 3.0 μm, manufactured by Epson Atmix) are mixed and dispersed uniformly with a high-speed rotating mixer. Then, resin composition 2 was prepared.

<Example 3: Preparation of resin composition 3>
In Example 1, KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was added to 30 parts by mass of SG-P3 (epoxy group-containing acrylic acid ester copolymer resin, manufactured by Nagase ChemteX Corporation, number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg, glass transition temperature 12° C., non-volatile content 15% by mass)) was changed to 200 parts by mass. A resin composition 3 was prepared in the same manner as in Example 1 except for the above matters.

<Example 4: Preparation of resin composition 4>
In Example 1, 30 parts by mass of KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was changed to 23 parts by mass of BL-1 (butyral resin, manufactured by Sekisui Chemical Co., Ltd.). A resin composition 4 was prepared in the same manner as in Example 1 except for the above matters.

<Example 5: Preparation of resin composition 5>
In Example 1, the amount of YX7553 (phenoxy resin, non-volatile content 30% by mass, manufactured by Mitsubishi Chemical Corporation) was changed from 35 parts by mass to 135 parts by mass, and KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was added. was not added. Resin composition 5 was prepared in the same manner as in Example 1 except for the above matters.

<Example 6: Preparation of resin composition 6>
In Example 1, the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 850 parts by mass to 1500 parts by mass. A resin composition 6 was prepared in the same manner as in Example 1 except for the above matters.

<Example 7: Preparation of resin composition 7>
In Example 1, the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 850 parts by mass to 500 parts by mass, and the amount of SO-C2 (manufactured by Admatechs) was changed from 35 parts by mass to 52.5 parts by mass. changed to department. Resin composition 7 was prepared in the same manner as in Example 1 except for the above matters.

<Example 8: Preparation of resin composition 8>
In Example 1, the amount of SO-C2 (manufactured by Admatechs) was changed from 35 parts by mass to 150 parts by mass. A resin composition 8 was prepared in the same manner as in Example 1 except for the above matters.

<Example 9: Preparation of resin composition 9>
In Example 1, the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 850 parts by mass to 600 parts by mass, and SO-C2 (manufactured by Admatechs) was not included. A resin composition 9 was prepared in the same manner as in Example 1 except for the above matters.

<Example 10: Preparation of resin composition 10>
In Example 3, the amount of LA-7054 (phenolic curing agent, non-volatile content 60%, manufactured by DIC) was changed from 14 parts by mass to 7 parts by mass, and HPC-8000-65T (active ester curing agent, non-volatile content 65% by mass, manufactured by DIC Corporation) was contained. A resin composition 10 was prepared in the same manner as in Example 3 except for the above matters.
The surface of the prepared resin composition 10 was measured using a scanning electron microscope (SEM). An enlarged photograph of the surface of the resin composition 10 is shown in FIG.

<Comparative Example 1: Preparation of Resin Composition 11>
In Example 1, the amount of KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was changed from 30 parts by mass to 100 parts by mass. A resin composition 11 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 2: Preparation of resin composition 12>
In Example 1, 30 parts by mass of KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was not included. A resin composition 12 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 3: Preparation of Resin Composition 13>
In Example 1, the amount of KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was changed from 30 parts by mass to 5 parts by mass, and the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 850 parts by mass. It was changed to 1800 parts by mass. A resin composition 13 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 4: Preparation of Resin Composition 14>
In Example 1, the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 850 parts by mass to 250 parts by mass, and the amount of SO-C2 (manufactured by Admatechs) was changed from 35 parts by mass to 52.5 parts by mass. changed to department. A resin composition 14 was prepared in the same manner as in Example 1 except for the above matters.

<Comparative Example 5: Preparation of Resin Composition 15>
In Example 9, KS-1 (polyvinyl acetal resin, manufactured by Sekisui Chemical Co., Ltd.) was added to 30 parts by mass of SG-P3 (epoxy group-containing acrylic acid ester copolymer resin, manufactured by Nagase ChemteX Corporation, number average molecular weight Mn: 850000 g/mol, epoxy value 0.21 eq/kg, glass transition temperature 12° C., non-volatile content 15% by mass), and the amount of AW2-08PF3F (manufactured by Epson Atmix) was changed from 600 parts by mass to 150 parts by mass. changed to department. A resin composition 15 was prepared in the same manner as in Example 9 except for the above matters.

<Comparative Example 6: Preparation of Resin Composition 16>
In Example 1, 850 parts by mass of AW2-08PF3F (manufactured by Epson Atmix) was changed to 500 parts by mass of HQ (carbonyl iron, manufactured by BASF). A resin composition 16 was prepared in the same manner as in Example 1 except for the above matters.

<Evaluation of laminating property>
A polyethylene terephthalate (hereinafter referred to as “PET”) film (thickness: 38 μm) was prepared as a support. The resin composition prepared in each example and each comparative example was uniformly applied on a PET film with a die coater so that the thickness of the resin composition layer after drying was 50 μm, and was heated at 70° C. to 120° C. (average 100° C.) for 7 minutes so that the amount of residual solvent in the resin composition layer was about 0.4% by mass, and an adhesive film was obtained.

Each adhesive film was laminated on both sides of the wiring board using a batch-type vacuum pressure laminator "MVLP-500" manufactured by Meiki Seisakusho. Lamination was carried out by reducing the pressure to 13 hPa or less for 30 seconds and then pressing at 100° C. with a pressing force of 0.74 MPa for 30 seconds. Evaluation was carried out by inspecting the appearance of the obtained laminate structure according to the following evaluation criteria. The results are shown in the table below.
Evaluation criteria ◯: There are no voids in the circuit portion of the wiring board, and the resin composition derived from the adhesive film flows sufficiently.
x: Voids are generated in the circuit portion of the wiring board, and the fluidity of the resin composition derived from the adhesive film during lamination is insufficient.

<Measurement of relative magnetic permeability and magnetic loss>
As a support, a PET film ("Fluoroge RL50KSE" manufactured by Mitsubishi Plastics, Inc.) treated with a fluororesin release agent (ETFE) was prepared. The resin composition prepared in each example and each comparative example was uniformly applied on the PET film with a die coater so that the thickness of the resin composition layer after drying was 50 μm, and The resin composition layer was dried at an average temperature of 100° C. for 7 minutes so that the amount of residual solvent in the resin composition layer was about 0.4% by mass, and an adhesive film was obtained. The resulting adhesive film was heated at 180° C. for 90 minutes to thermally cure the resin composition layer, and the support was peeled off to obtain a sheet-like cured product. The obtained cured product was cut into a test piece having a width of 5 mm and a length of 18 mm to obtain an evaluation sample. This evaluation sample is measured by the 3-turn coil method using "HP8362B" (trade name) manufactured by Agilent Technologies, with a measurement frequency in the range of 10 MHz to 100 MHz, and the relative permeability (μ ') and magnetic loss (μ'') were measured. Further, relative magnetic permeability (μ′) and magnetic loss (μ″) were measured at a room temperature of 23° C. with a measurement frequency of 100 MHz to 10 GHz by the short-circuit stripline method. The table below shows the relative magnetic permeability when the measurement frequencies are 10 MHz, 100 MHz, 1 GHz and 3 GHz, and the magnetic loss when the measurement frequencies are 10 MHz and 100 MHz.

<Measurement of elastic modulus>
As a support, a PET film ("Fluoroge RL50KSE" manufactured by Mitsubishi Plastics, Inc.) treated with a fluororesin release agent (ETFE) was prepared. The resin composition prepared in each example and each comparative example was uniformly applied on the PET film with a die coater so that the thickness of the resin composition layer after drying was 50 μm, and The resin composition layer was dried at an average temperature of 100° C. for 7 minutes so that the amount of residual solvent in the resin composition layer was about 0.4% by mass, and an adhesive film was obtained. The resulting adhesive film was heated at 180° C. for 90 minutes to thermally cure the resin composition layer, and the support was peeled off to obtain a sheet-like cured product. The resulting cured body was subjected to a tensile test using a Tensilon universal testing machine (manufactured by A&D) in accordance with Japanese Industrial Standards (JIS K7127) to measure the tensile modulus.

<Measurement of warpage amount>
A polyethylene terephthalate (hereinafter referred to as “PET”) film (thickness: 38 μm) was prepared as a support. The resin composition prepared in each example and each comparative example was uniformly applied on a PET film with a die coater so that the thickness of the resin composition layer after drying was 50 μm, and was heated at 70° C. to 120° C. (average 100° C.) for 7 minutes so that the amount of residual solvent in the resin composition layer was about 0.4% by mass, and an adhesive film was obtained. The obtained adhesive film was punched into a 100 mm square, the support was peeled off, and eight layers of the resin composition layer were stacked on top of each other. R1515A” was laminated using a batch-type vacuum pressure laminator “MVLP-500” manufactured by Meiki Seisakusho. Lamination was carried out by reducing the pressure to 13 hPa or less for 30 seconds and then pressing at 100° C. with a pressing force of 0.74 MPa for 30 seconds. Then, it was thermally cured at 180° C. for 30 minutes to obtain a laminated structure. The laminated structure was placed on a horizontal table, and the distance from the table to the edge of the laminated structure was defined as the amount of warpage. Evaluation was performed according to the following evaluation criteria.
Evaluation Criteria ○: Warpage amount is 7 mm or more and less than 20 mm ×: Warpage amount is 20 mm or more or 6 mm or less

<Evaluation of flame retardancy>
A polyethylene terephthalate (hereinafter referred to as “PET”) film (thickness: 38 μm) was prepared as a support. The resin composition prepared in each example and each comparative example was uniformly applied on a PET film with a die coater so that the thickness of the resin composition layer after drying was 50 μm, and was heated at 70° C. to 120° C. (average 100° C.) for 7 minutes so that the amount of residual solvent in the resin composition layer was about 0.4% by mass, and an adhesive film was obtained. The resulting adhesive film was applied to both sides of a substrate obtained by etching away the copper foil of a copper-clad laminate ("679-FG" manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.2 mm. (manufactured by Meiki Co., Ltd.), and laminated on both sides of the laminate. Lamination was performed by reducing the pressure for 30 seconds to an air pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa. After peeling off the PET film of the support, the adhesive films were laminated on both sides of the resin composition layer under the lamination conditions described above. Thereafter, the PET film was peeled off and heat cured at 180° C. for 90 minutes to obtain a flame retardant test sample. A width of 12.7 mm and a length of 127 mm were cut out, and the cut surface was polished with a polishing machine (RotoPol-22 manufactured by Struers). A set of the above five samples was subjected to a flame retardancy test according to the UL94 vertical flame retardance test. A case in which five samples remained unburned after 10 seconds of indirect flame was evaluated as "O", and a case in which there were no unburned samples after 10 seconds of indirect flame was evaluated as "x".

It can be seen that Examples 1 to 10 are excellent in lamination properties, magnetic loss, relative magnetic permeability, elastic modulus, amount of warpage, warpage test, and flame retardancy. It can be seen that Examples 1 to 10 have significantly improved relative magnetic permeability in the range of 10 MHz to 200 MHz and reduced magnetic loss.
As shown in FIG. 5, the resin composition of Example 10 forms a sea-island structure consisting of a matrix phase and a dispersed phase, and component (D) is unevenly distributed on the matrix phase side. It is considered that the relative magnetic permeability of the cured product of the resin composition of Example 10 is improved because the component (D) is unevenly distributed on the matrix phase side.

On the other hand, Comparative Examples 1 and 4 to 6 with an elastic modulus of less than 7 GPa, and Comparative Examples 2 and 3 with an elastic modulus of more than 18 GPa have lamination properties, relative magnetic permeability at 10 MHz to 200 MHz, magnetic loss, elastic modulus, and warpage. Any of the amount, warpage test, and flame retardancy were worse than those of Examples 1 to 10, and could not be used as a resin composition. In Comparative Examples 1 and 3, the amount of warpage was large and exceeded the limit of measurement, so the amount of warpage could not be measured. Moreover, flame retardancy could not be evaluated.

In each example, it has been confirmed that the same results as in the above examples are obtained even if the components (E) to (F) are not contained, although there are differences in degree.

10 wiring board 20 core base material (inner layer circuit board)
20a first main surface 20b second main surface 22 through hole 22a wiring in through hole 24 external terminal 30 magnetic part 32 first magnetic layer 34 second magnetic layer 36 via hole 36a wiring in via hole 38 third magnetic layer 40 coiled conductivity Structure 42 First wiring layer 42a Land 44 Second wiring layer 46 Third wiring layer 50 Base material with metal layer with carrier 51 Base material 52 Metal layer with carrier 521 First metal layer 522 Second metal layer

Claims (22)

(A) a thermosetting resin that is an epoxy resin having a weight average molecular weight of 100 or more and 5000 or less;
(B) an epoxy resin curing agent;
(C) a thermoplastic resin having a weight average molecular weight of 30,000 or more and 1,000,000 or less, and (D) a magnetic filler,
(D) The content of the component is 75% by mass or more and less than 95% by mass when the non-volatile matter in the resin composition is 100% by mass,
When the content mass of the resin component in the resin composition is a1 and the content mass of the component (C) is c1, (c1/a1) × 100 is 35 or more and 80 or less,
The resin composition is dried at 70° C. to 120° C. (average 100° C.) for 7 minutes and heated at 180° C. for 90 minutes to thermally cure. is 7 GPa or more and 18 GPa or less. 2. The resin composition according to claim 1 , further comprising (E) an inorganic filler other than the magnetic filler. The resin composition according to claim 2 , wherein e1/d1 is 0.02 or more and 0.19 or less, where d1 is the content of component (D) and e1 is the content of component (E). 4. The resin composition according to claim 2 , wherein the component (E) is silica . The resin composition according to any one of claims 1 to 4 , wherein the epoxy resin is one or more epoxy resins selected from epoxy resins having a biphenyl skeleton and epoxy resins having a condensed ring structure. 6. The resin composition according to any one of claims 1 to 5 , wherein component (B) is one or more curing agents selected from phenolic curing agents and active ester curing agents. The resin composition according to any one of claims 1 to 6 , wherein component (C) is one or more thermoplastic resins selected from phenoxy resins, polyvinyl acetal resins, butyral resins, and acrylic resins. The resin composition according to any one of claims 1 to 7 , wherein the resin composition forms a sea-island structure consisting of a matrix phase and a dispersed phase, and the component (D) is unevenly distributed on the matrix phase side. The resin composition according to any one of claims 1 to 8, wherein component (D) has an average particle size of 0.01 µm or more and 8 µm or less and an aspect ratio of component (D) is 2 or less. . The resin composition according to any one of claims 1 to 9 , wherein component (D) is an Fe alloy containing one or more elements selected from Si, Al, and Cr. The resin composition is dried at 70° C. to 120° C. (average 100° C.) for 7 minutes and heated at 180° C. for 90 minutes to heat and cure. The cured product has a relative magnetic permeability of 5 or more and 20 or less at a frequency of 100 MHz. , The resin composition according to any one of claims 1 to 10 . The resin composition is dried at 70° C. to 120° C. (average 100° C.) for 7 minutes and heat-cured at 180° C. for 90 minutes. The resin composition according to any one of claims 1 to 11 , wherein: The resin composition is dried at 70° C. to 120° C. (average 100° C.) for 7 minutes and heated at 180° C. for 90 minutes to thermally cure, and the cured product has a relative magnetic permeability of 5 to 20 at a frequency of 10 MHz. , a relative magnetic permeability of 5 or more and 20 or less at a frequency of 100 MHz, a relative magnetic permeability of 4 or more and 16 or less at a frequency of 1 GHz, and a relative magnetic permeability of 2 or more and 10 or less at a frequency of 3 GHz or more . The resin composition according to any one of items 1 and 2. 14. The resin composition according to any one of claims 1 to 13 , which is used for forming a magnetic layer of a wiring board provided with an inductor element. 15. The resin composition according to claim 14 , wherein the frequency at which the inductor element functions is 10 to 200 MHz. A cured product obtained by thermally curing the resin composition according to any one of claims 1 to 13 . An adhesive film comprising a support and a resin composition layer formed of the resin composition according to any one of claims 1 to 13 provided on the support. It has a magnetic layer that is a cured product of the resin composition layer of the adhesive film according to claim 17 , and a conductive structure at least a part of which is embedded in the magnetic layer,
Wiring board with built-in inductor element, comprising the conductive structure and an inductor element formed by a portion of the magnetic layer extending in the thickness direction of the magnetic layer and surrounded by the conductive structure. . 19. The wiring board with a built-in inductor element according to claim 18 , wherein the frequency at which the inductor element functions is 10 to 200 MHz. A printed wiring board using the inductor element built-in wiring board according to claim 18 or 19 as an inner layer substrate. A chip inductor component obtained by singulating the wiring board with a built-in inductor element according to claim 18 or 19 . A printed wiring board on which the chip inductor component according to claim 21 is surface-mounted.

Images