JP6624561B2 - Resin sheet, inductor parts - Google Patents

Description

  The present invention relates to a resin sheet and an inductor component used for various components used in electronic devices and the like, modules, and the like.

  Conventionally, individual components such as capacitors, resistors, and inductors and various modules are resin-sealed with semiconductor elements by potting molding using a liquid molding material or transfer molding using a powdery or tablet-like molding material. It is manufactured by:

  On the other hand, in the field of electronic equipment, a resin sheet is also used as a molding material in a form other than liquid, powder, and tablet forms (for example, see Patent Document 1). In general, resin sheets are used for molding over a large area because of their forms, compared to liquid, powder and tablet molding materials. Specific applications of the resin sheet include, for example, an application for filling gaps between circuits in a thick copper circuit board, an application for manufacturing a component built-in module incorporating components, and a dimple by filling a through hole in a printed wiring board. And the like for suppressing the formation of slag.

JP 2014-11467 A

  Recently, it has been actively performed to improve properties such as heat resistance, thermal conductivity, thermal expansion coefficient, magnetic permeability, and dielectric constant of a cured product by including a high proportion of an inorganic filler in a molding material. .

  However, in the case of the resin sheet, if the content of the inorganic filler is high, flexibility is lost, cracks are easily generated, and the sheet is easily broken. As described above, the resin sheet having a high content of the inorganic filler has a problem that the handleability at room temperature is poor and the stress relaxation property is low even after curing.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a resin sheet and an inductor component that can improve the handleability at room temperature before curing and the stress relaxation after curing.

The resin sheet according to the present invention,
A semi-cured resin sheet,
The resin sheet contains an epoxy resin, a phenoxy resin, a linear elastomer, a curing agent, and an inorganic filler,
The content of the linear elastomer is 0.01 to 0.5 parts by mass with respect to a total of 100 parts by mass of the components of the resin sheet excluding the linear elastomer,
The content of the inorganic filler is 80 to 98% by mass with respect to the total amount of the resin sheet, the inorganic filler contains two or more iron-based alloys having different average particle diameters, and the iron-based alloy is soft. It is characterized by containing a magnetic iron-silicon alloy.

  It is preferable that the iron-based alloy further includes a soft magnetic iron-aluminum-silicon-based alloy.

  It is preferable that the inorganic filler is subjected to insulation treatment.

  It is preferable that the minimum average particle diameter is 5 nm to 10 μm.

  It is preferable that the maximum average particle diameter is 10 to 150 μm. It is preferable that the resin sheet further contains a surface treatment agent.

The linear elastomer preferably has a weight average molecular weight of 20,000 to 1,000,000 .

The inductor component according to the present invention,
Coiled wiring,
And a resin layer covering the coil-shaped wiring,
The resin layer is formed of a cured product of the resin sheet.

  According to the present invention, despite the fact that the resin sheet contains a high proportion of the inorganic filler, the phenoxy resin and the linear elastomer are further contained, so that the resin sheet before curing can be handled at room temperature. In addition, the stress relaxation of the cured resin sheet can be enhanced.

FIG. 1 includes FIGS. 1A to 1C, and FIGS. 1A to 1C are cross-sectional views illustrating an example of a method for manufacturing a resin sheet. 2 includes FIGS. 2A and 2B, FIG. 2A is a front view showing an example of an inductor component, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A.

  Hereinafter, embodiments of the present invention will be described.

  The resin sheet of the present embodiment is a semi-cured resin sheet. The semi-cured state is an intermediate stage of the curing reaction, and is also called a B stage. The varnish state is also called an A stage and the fully cured state is also called a C stage, and the semi-cured state is at an intermediate stage between them. When the resin sheet is heated, it is once melted and then completely cured to form a C stage.

  The resin sheet contains an epoxy resin, a phenoxy resin, a linear elastomer, a curing agent, and an inorganic filler.

  First, components constituting the resin sheet will be described.

  The epoxy resin is a thermosetting resin having an epoxy group, and is not particularly limited. Specific examples of the epoxy resin include a bisphenol F epoxy resin, a polyfunctional epoxy resin, a biphenyl epoxy resin, a bisphenol A epoxy resin, a cresol novolak epoxy resin, and a phenol novolak epoxy resin. A polyfunctional epoxy resin is a resin having three or more epoxy groups in one molecule. The epoxy resin contained in the resin sheet may be only one type or two or more types. The content of the epoxy resin is not particularly limited, but is preferably, for example, 75 to 95% by mass based on the total amount of the components of the resin sheet excluding the linear elastomer and the inorganic filler.

  The phenoxy resin is a resin that has been polymerized into a linear form by a condensation reaction between bisphenol A and epichlorohydrin. The phenoxy resins include those having an epoxy group at the end and those having a hydroxyl group. The weight average molecular weight (Mw) of the phenoxy resin is preferably from 50,000 to 100,000, more preferably from 60,000 to 80,000. The content of the phenoxy resin is not particularly limited, but is preferably, for example, 1 to 10% by mass based on the total amount of the components of the resin sheet excluding the linear elastomer and the inorganic filler.

  The linear elastomer is a polymer material in which a linear polymer is intricately entangled and has an overall shape that is linear, and has a rubber-like elasticity at room temperature (for example, 20 to 30 ° C.). Not limited. Since the linear elastomer is linear, it is easily entangled with other constituent components of the resin sheet, and can be uniformly distributed throughout the resin sheet to exhibit appropriate rubber-like elasticity. Specific examples of the linear elastomer include acrylonitrile butadiene rubber (NBR), acrylic rubber (ACM), and butadiene rubber (BR). The terminal group of the linear elastomer is, for example, a carboxy group, but is not particularly limited. Since the linear elastomer can have a carboxy group, it can react with the epoxy resin to form a bond when the resin sheet is semi-cured or completely cured. The linear elastomer contained in the resin sheet may be only one kind or two or more kinds.

  The elastomer includes a particulate elastomer in addition to the linear elastomer. The particulate elastomer is a polymer material in which a linear polymer is cross-linked in a molecule or between molecules to have a whole particle shape, and has rubber-like elasticity at room temperature. Since the particulate elastomer is particulate, the particulate elastomer is less likely to be entangled with other constituent components of the resin sheet, and in particular, the inorganic filler is easily aggregated. Therefore, the linear elastomer is more preferable than the particulate elastomer. As long as the effects of the present invention are not impaired, the resin sheet may contain the particulate elastomer in addition to the linear elastomer.

  The acrylonitrile butadiene rubber (NBR) is a copolymer of acrylonitrile and 1,3-butadiene. Depending on the content of the acrylonitrile, the acrylonitrile-butadiene rubber has a low nitrile type (acrylonitrile content of less than 25% by mass), a medium nitrile type (acrylonitrile content of 25 to 35% by mass), and a high nitrile type (acrylonitrile content of 35% by mass). (Super).

  The weight average molecular weight (Mw) of the linear elastomer is preferably from 20,000 to 1,000,000, and more preferably from 50,000 to 500,000. Although the content of the linear elastomer is not particularly limited, for example, it may be 0.01 to 0.5 part by mass with respect to 100 parts by mass of the total components of the resin sheet excluding the linear elastomer. preferable.

  The curing agent is an additive that causes a curing reaction of the epoxy resin to form a three-dimensional structure, and is not particularly limited. Specific examples of the curing agent include dicyandiamide, phenol-based curing agent, cyclopentadiene, amine-based curing agent, and acid anhydride. The phenolic curing agent is a curing agent having two or more phenolic hydroxyl groups in one molecule. Specific examples of the phenolic curing agent include a phenol novolak resin, a phenol aralkyl resin, a naphthalene-type phenol resin, and bisphenol. Specific examples of the bisphenol include bisphenol A and bisphenol F. Specific examples of the amine-based curing agent include diaminodiphenylamine, triethylenetetramine, and boron trifluoride monoethylamine. The curing agent contained in the resin sheet may be only one kind or two or more kinds. The content of the curing agent is not particularly limited, but is preferably, for example, 0.5 to 20% by mass based on the total amount of the components of the resin sheet excluding the linear elastomer and the inorganic filler.

  The inorganic filler is not particularly limited.

  The inorganic fillers can be broadly classified into conductive fillers and insulating fillers depending on the presence or absence of conductivity. That is, the conductive filler has conductivity, and the insulating filler has electrical insulation. Here, the conductive filler may be used as it is, or may be used after being insulated as described later. In the latter case, the conductive filler after the insulation treatment is treated as the insulating filler.

  The inorganic fillers can be broadly classified into magnetic fillers and non-magnetic fillers depending on the presence or absence of magnetism. That is, the magnetic filler has magnetism, and the non-magnetic filler has no magnetism. Here, the insulating filler is the non-magnetic filler. The magnetic filler is the conductive filler, and may be used as it is, or may be used after being insulated as described later. In the latter case, the magnetic filler after the insulation treatment is treated as the insulating filler.

  As described above, in the present embodiment, the insulating filler includes, in addition to the inorganic filler having an electrically insulating property without the insulation treatment, the conductive filler after the insulation treatment, and the magnetic filler after the insulation treatment. Fillers are also included.

  Preferably, the inorganic filler contains at least one selected from the group consisting of iron, iron-based alloys, ferrite-based alloys, and cobalt-based alloys.

Iron means high-purity iron (pure iron) having a purity of, for example, 99.90 to 99.95%. Specific examples of iron include carbonyl iron, armco iron, sponge iron, and electrolytic iron. Carbonyl iron is obtained by pyrolyzing iron carbonyl iron Fe (CO) ₅ .

  A specific example of the iron-based alloy is a soft magnetic iron alloy. Specific examples of the soft magnetic iron alloy include soft magnetic iron (Fe) -silicon (Si) based alloy, soft magnetic iron (Fe) -nitrogen (N) based alloy, and soft magnetic iron (Fe) -carbon (C) based alloy. Alloy, soft magnetic iron (Fe) -boron (B) alloy, soft magnetic iron (Fe) -phosphorus (P) alloy, soft magnetic iron (Fe) -aluminum (Al) alloy, soft magnetic iron (Fe) -Aluminum (Al) -silicon (Si) based alloy, permendur (Fe-Co), Fe-Co-V alloy.

Specific examples of the ferrite-based alloy include an alloy represented by the general formula MFe ₂ O ₄ or MO · nFe ₂ O ₃ (where M is a divalent metal element and n is an integer), Mn—Zn-based ferrite, and Ni-based ferrite. And Mg-Zn ferrite. As a specific example of the alloy represented by the above general formula MO · nFe ₂ O ₃ (where M is a divalent metal element and n is an integer), a CoO · Fe ₂ O ₃ alloy can be mentioned.

Specific examples of the cobalt-based alloy include a CoO.Fe ₂ O ₃ alloy, a soft magnetic cobalt alloy, permendur (Fe—Co), and a Co-based amorphous alloy. Permendur (Fe-Co) and Fe-Co-V alloys are both iron-based alloys and cobalt-based alloys. The CoO.Fe ₂ O ₃ alloy is both a ferrite alloy and a cobalt alloy.

  Other specific examples of the inorganic filler include nickel, a soft magnetic nickel alloy, and cobalt.

  Iron, iron-based alloy, ferrite-based alloy, cobalt-based alloy is a magnetic material, and when such an inorganic filler is contained in the resin sheet as the magnetic filler, the resin sheet can be used as a magnetic sheet. it can. The resin sheet as a magnetic sheet is suitable as a material for an electronic component such as an inductor component or an electromagnetic shielding material. By including the inorganic filler in which two or more kinds of magnetic materials described above are combined in the resin sheet, it is possible to adjust the magnetic permeability of the cured product of the resin sheet at a predetermined frequency.

  The content of the inorganic filler is 80 to 98% by mass based on the total amount of the resin sheet. In this way, despite the fact that the resin sheet contains the inorganic filler in a high ratio, the phenoxy resin and the linear elastomer are further contained, so that the resin sheet before curing at room temperature is cured. Handleability and stress relaxation of the cured resin sheet can be enhanced. If the content of the inorganic filler is less than 80% by mass, the properties of the inorganic filler may not be sufficiently exhibited in the cured resin sheet. For example, when the inorganic filler is the magnetic filler, a high magnetic permeability may not be obtained for the cured resin sheet. If the content of the inorganic filler exceeds 98% by mass, the handleability of the resin sheet before curing at room temperature may be deteriorated, and the fluidity of the resin sheet at the time of melting may be reduced, and the resin after curing may be reduced. The stress relaxation of the sheet is also reduced.

  When the inorganic filler is the insulating filler, the resin sheet may have an insulating property. Specific examples of the insulating filler include silica and alumina.

  In a case where the inorganic filler is the conductive filler, the conductive filler may come into contact with each other to form a path through which a current can flow, whereby the resin sheet may have conductivity. In particular, in the case where an electrically insulating resin sheet is manufactured using the conductive filler as the inorganic filler, the inorganic filler is preferably subjected to an insulation treatment. The insulating treatment can be performed, for example, by coating the surface of each particle constituting the inorganic filler with an insulating material. The insulating material is not particularly limited, and may be an inorganic material or an organic material. An insulating film is formed on the surface of the constituent particles of the inorganic filler after the insulating treatment.

  Specific examples of the organic material include an epoxy resin that is a thermosetting resin. When the inorganic filler is subjected to insulation treatment using the organic material, for example, a spray drying method can be used. That is, when the organic material is dissolved in an appropriate solvent, and the mixture obtained by adding and dispersing the inorganic filler to the organic material is sprayed into a high-temperature gas and rapidly dried, the organic insulating film made of the organic material becomes a surface. Can be obtained.

  Specific examples of the inorganic material include a phosphate. When the inorganic filler is subjected to insulation treatment using the inorganic material, for example, mechanochemical treatment can be used. That is, when the powdered inorganic filler and the inorganic material were kneaded, the inorganic filler was relatively hard and the inorganic material was soft, so that the inorganic insulating film made of the inorganic material was formed on the surface. An inorganic filler can be obtained.

  As described above, when the inorganic filler is insulated, the constituent particles of the inorganic filler come into contact with each other via the insulating film, so that a path through which a current can flow is cut off, so that the resin sheet has an insulating property. May be provided.

  When the inorganic filler contains only the insulating filler (first case), the insulating property of the resin sheet can be the highest. When the inorganic filler contains only the conductive filler that has not been subjected to insulation treatment (second case), the insulation of the resin sheet may be the lowest. When the inorganic filler contains the insulating filler and the conductive filler that has not been subjected to insulation treatment (third case), the insulating property of the resin sheet is lower than that of the first case, and is lower than that of the second case. Can be high. The reason for this is that there may be places where the insulating filler is interposed between the conductive fillers inside the resin sheet.

  In the above third case, that is, in the case where the inorganic filler contains the conductive filler and the insulating filler, the insulating property of the resin sheet is higher than in the second case, so that Can be secured. In order to further increase the insulating property of the resin sheet, it is preferable that the average particle diameter of the insulating filler is smaller than the average particle diameter of the conductive filler. In this case, the individual particles constituting the insulating filler uniformly adhere to the surfaces of the individual particles constituting the conductive filler, and an insulating film made of the insulating filler is formed. As described above, since the constituent particles of the conductive filler are in contact with each other via the insulating film formed of the constituent particles of the insulating filler, a path through which current can flow is cut off, so that the resin sheet has an insulating property. May be provided. The average particle size of the conductive filler is preferably 0.5 to 150 μm, more preferably 1 to 50 μm, and the average particle size of the insulating filler is preferably 5 nm to 2 μm, more preferably 10 to 50 nm. In the present embodiment, the average particle diameter means a particle diameter (50% particle diameter, median diameter) at an integrated value of 50% in a particle size distribution obtained by a laser diffraction / scattering method. When the inorganic filler contains the conductive filler and the insulating filler, the content of the insulating filler is preferably 0.2 to 2% by mass based on the total amount of the inorganic filler. More preferably, the content is 3 to 1% by mass.

  When the inorganic filler contains the conductive filler and the insulating filler, the conductive filler and the insulating filler may be formed of the same material, and the conductive filler and the insulating filler may be different. It may be formed of a material.

  As an example in which the conductive filler and the insulating filler are formed of the same material, the former is iron or an iron-based alloy, and the latter is the same type of iron or an iron-based alloy, and is subjected to insulation treatment. Things. In this case, the magnetic properties can be improved while ensuring the insulating properties of the resin sheet.

  As an example in which the conductive filler and the insulating filler are formed of different materials, the former is a ferrite-based alloy having low insulation properties, and the latter is a ferrite-based alloy having high insulation properties. In this case, the magnetic properties can be improved while ensuring the insulating properties of the resin sheet, and particularly, the high frequency characteristics can be improved. Ferrite alloys have different degrees of insulation depending on the material, and there are some that can be used as the conductive filler and those that can be used as the insulating filler without insulation treatment.

  It is also preferable that the inorganic filler contains two or more iron-based alloys having different average particle diameters. By filling the gap between the constituent particles of the iron-based alloy having a large average particle diameter with the constituent particles of the iron-based alloy having a small average particle diameter, the resin sheet can contain the inorganic filler in a high ratio. . The maximum average particle diameter is preferably from 10 to 150 μm, more preferably from 10 to 50 μm. The minimum average particle size is preferably from 0.5 to 10 μm, more preferably from 0.5 to 5 μm. Since the inorganic filler is an iron-based alloy, the magnetic permeability of the resin sheet can be increased.

  It is also preferable that the inorganic filler contains two or more cobalt-based alloys having different average particle diameters. By filling the gap between the constituent particles of the cobalt-based alloy having a large average particle diameter with the constituent particles of the cobalt-based alloy having a small average particle diameter, the resin sheet can contain the inorganic filler in a high ratio. . The maximum average particle diameter is preferably from 10 to 100 μm, more preferably from 10 to 50 μm. The minimum average particle diameter is preferably from 5 nm to 10 μm, more preferably from 5 nm to 3 μm. Since the inorganic filler is a cobalt-based alloy, high-frequency characteristics of the magnetic permeability of the resin sheet can be improved. In particular, the high frequency characteristics of the imaginary component (μ ″) of the complex magnetic permeability can be improved.

  When the inorganic filler contains two or more types of constituent particles having different average particle diameters, the minimum average particle diameter is preferably from 5 nm to 10 μm, more preferably from 5 nm to 3 μm. By filling gaps between constituent particles having a large average particle diameter with constituent particles having a small average particle diameter, the resin sheet can contain the inorganic filler at a high ratio. When the constituent particles are a magnetic material, the magnetic properties of the resin sheet can be improved. In particular, when a nano-sized cobalt-based alloy having an average particle diameter of 5 to 50 nm is contained in the inorganic filler, the magnetic properties of the resin sheet in a high-frequency band can be further improved.

  It is also preferable that the resin sheet further contains a surface treatment agent. The surface treatment agent contains a coupling agent and a dispersant. Specific examples of the coupling agent include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane. Specific examples of the dispersant include polyoxyethylene-laurylamine. By the coupling agent, affinity between the inorganic filler and other components constituting the resin sheet can be increased. The dispersant allows the inorganic filler to be uniformly dispersed in the resin sheet. The content of the coupling agent is not particularly limited, but is preferably, for example, 0.2 to 2 parts by mass with respect to 100 parts by mass of the inorganic filler. The content of the dispersant is not particularly limited, but is preferably, for example, 0.05 to 1 part by mass with respect to 100 parts by mass of the inorganic filler.

  The resin sheet may contain a curing accelerator in order to accelerate the curing reaction of the epoxy resin. Specific examples of the curing accelerator include tertiary amines, tertiary amine salts, imidazole, phosphine, and phosphonium salts. The content of the curing accelerator is not particularly limited.

  Next, a method for manufacturing the resin sheet of the present embodiment will be described.

  First, a resin component is prepared by blending the epoxy resin, the phenoxy resin, the linear elastomer, the surface treating agent (the coupling agent and the dispersant), and a solvent. It should be noted that those not blending at least one of the coupling agent and the dispersant may also be referred to as resin components. Specific examples of the solvent include methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK). One of the solvents may be used alone, or two or more of the solvents may be used in combination. When two or more solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited.

  Next, the inorganic filler is added to the resin component and kneaded, and finally, the curing agent is added and stirred to prepare a final slurry. When the curing accelerator is used, it may be added together with the curing agent.

  The final slurry may be prepared as follows. The surface of the inorganic filler is previously treated with the coupling agent. Next, the epoxy resin, the phenoxy resin, the linear elastomer, the dispersant, and the solvent are blended to prepare the resin component. Next, an inorganic filler after the surface treatment is added to the resin component and kneaded, and finally, the curing agent is added and stirred to prepare a final slurry. In this case, when the curing accelerator is used, it may be added together with the curing agent. The coupling agent can increase the affinity between the inorganic filler and other components in the final slurry. By the dispersant, the inorganic filler can be uniformly dispersed in the final slurry, and aggregation and precipitation of the inorganic filler can be suppressed.

  Next, as shown in FIGS. 1A to 1C, the resin sheet 1 can be manufactured by applying the final slurry 3 on a film 4 and drying it. Specific examples of the film 4 include a polyethylene terephthalate (PET) film. The thickness of the film 4 is not particularly limited. It is preferable that the surface of the film 4 on which the final slurry 3 is applied has been subjected to a release treatment in advance. The thickness of the resin sheet 1 is not particularly limited, but is, for example, 20 to 200 μm.

  When manufacturing a resin sheet containing two or more types of inorganic fillers having different average particle diameters, first, the resin component is prepared as described above. Next, the inorganic filler is added to the resin component in order of increasing average particle diameter, kneaded, and finally, the curing agent is added and stirred to prepare a final slurry. When the curing accelerator is used, it may be added together with the curing agent. As described above, when the inorganic filler having the large average particle diameter is added from the inorganic filler having a large average particle diameter, even if the inorganic filler having the small average particle diameter is added and aggregated later, the aggregate is dispersed while the inorganic filler having the large average particle diameter is loosened. Go. Therefore, in the gap between the constituent particles of the inorganic filler having a large average particle diameter, the constituent particles of the inorganic filler having a small average particle diameter can easily enter, and the entire inorganic filler can be uniformly dispersed in the final slurry. , Aggregation and precipitation can be suppressed.

  When producing a resin sheet containing two or more kinds of inorganic fillers having different average particle diameters, the final slurry may be prepared as follows. The surface of each inorganic filler having a different average particle diameter is previously treated with the coupling agent. Next, the epoxy resin, the phenoxy resin, the linear elastomer, the dispersant, and the solvent are blended to prepare the resin component. Next, the inorganic filler after the surface treatment is added to the resin component in order of increasing average particle diameter and kneaded, and finally, the curing agent is added and stirred to prepare a final slurry. In this case, when the curing accelerator is used, it may be added together with the curing agent. By the coupling agent, affinity between two or more inorganic fillers having different average particle diameters and other components in the final slurry can be increased. By the dispersant, two or more kinds of inorganic fillers having different average particle diameters can be more uniformly dispersed in the final slurry.

  Next, as shown in FIGS. 1A to 1C described above, the resin sheet 1 can be manufactured by applying and drying the final slurry 3 on the film 4.

  Since the resin sheet is excellent in tensile strength, it is hardly torn when peeled from the film and has flexibility. As described above, the handleability of the resin sheet before curing at room temperature is improved.

  Next, the inductor component of the present embodiment will be described.

  2A and 2B show an example of the inductor component 2. FIG. The inductor component 2 includes a coil-shaped wiring 5 and a resin layer 6. The coil-shaped wiring 5 is formed in a rectangular spiral shape, but is not limited to this shape. One end of the coiled wiring 5 is a first electrode 71 on the inside, and the other end is a second electrode 72 on the outside. The first electrode 71 and the second electrode 72 are exposed to the outside. The resin layer 6 covers the coiled wiring 5 except for the first electrode 71 and the second electrode 72. The resin layer 6 is formed of a cured product of the resin sheet 1. It is preferable that the cured product has electrical insulation properties and contains an inorganic filler that is a magnetic material. Since the stress relaxation of the cured product, that is, the resin sheet 1 after curing is enhanced, even if stress is generated in the resin layer 6 and the coiled wiring 5 by heating, for example, the resin layer 6 Since a stress relaxing action acts between the coil-shaped wiring 5 and the coil-shaped wiring 5, the occurrence of cracks can be suppressed. Therefore, the inductor component 2 has stable electromagnetic characteristics and high reliability.

  The inductor component 2 can be manufactured, for example, as follows. First, the coil-shaped wiring 5 is formed on the surface of the resin sheet 1. Specific examples of the method of forming the coiled wiring 5 include an electrolytic plating method, an electroless plating method, a punching method of a metal foil, a wet etching method, a dry etching method, a sputtering method, and a vapor deposition method. Next, another resin sheet 1 is overlaid on the surface on which the coil-shaped wiring 5 is formed so that the second electrode 72 is exposed, and is heated and pressed. By heating and pressing, the two resin sheets 1 sandwiching the coiled wiring 5 are melted and filled in the gap between the coiled wirings 5. Then, when the resin layer 6 covering the first electrode 71 is removed to expose the first electrode 71, the inductor component 2 as shown in FIGS. 2A and 2B can be obtained. The structure of the inductor component 2 is not limited to those shown in FIGS. 2A and 2B. The inductor component can be used for signals, high frequencies, power supplies, and the like.

  Hereinafter, the present invention will be described specifically with reference to Examples.

  The following components were used as components of the resin sheet.

(Epoxy resin)
・ Bisphenol F epoxy resin (Mitsubishi Chemical Corporation "jER 807")
・ Polyfunctional epoxy resin (Printec Co., Ltd. “TECHMORE VG3101”)
・ Biphenyl type epoxy resin (Mitsubishi Chemical Corporation "jER YX4000H")
(Phenoxy resin)
-Nippon Steel & Sumitomo Chemical Corporation "YP-50" (weight average molecular weight (Mw) 60000-80000)
(Linear elastomer)
Acrylonitrile butadiene rubber (JSR Corporation, medium nitrile type (acrylonitrile content 27% by mass), weight average molecular weight (Mw) 400,000)
(Curing agent)
・ Dicyandiamide ・ Phenolic curing agent (MEH-7500, Meiwa Kasei Co., Ltd.)
(Inorganic filler)
・ Magnetic material A (soft magnetic iron (Fe) -silicon (Si) alloy, average particle diameter 10 μm)
・ Magnetic material B (carbonyl iron, average particle size 2 μm)
・ Magnetic material C (Mn-Zn ferrite, average particle size 1 μm)
-Magnetic material D (Fe-Co-V alloy, average particle size 15 m)
・ Magnetic material E (CoO.Fe ₂ O ₃ alloy, average particle diameter 20 nm)
・ Magnetic material F (Fe-Co-V alloy, average particle diameter 15 µm, insulation treatment with inorganic material)
・ Silica (average particle diameter 10nm)
(Curing accelerator)
・ 2-ethyl-4-methylimidazole (2E4MZ)
(Coupling agent)
・ Epoxysilane (Momentive Performance Materials Japan GK, "A-187", 3-glycidoxypropyltrimethoxysilane)
(Dispersant)
・ Polyoxyethylene-laurylamine (NOF Corporation, “Nymeen L-202”)
(Example 1)
First, a resin component was prepared by blending an epoxy resin, a phenoxy resin, a linear elastomer, a surface treating agent, and a solvent so as to have the contents shown in Table 1. The solvent is a mixture of methyl ethyl ketone and N, N-dimethylformamide at a mass ratio of 1: 1.

  On the other hand, a magnetic material A and a magnetic material B, which are inorganic fillers, were added to the above resin components and kneaded, and finally, a curing agent and a curing accelerator were added and stirred to prepare a final slurry.

  The final slurry was applied to the surface of the release-treated polyethylene terephthalate film and dried to produce a resin sheet having a thickness of 150 μm.

(Example 2)
First, a resin component was prepared by blending an epoxy resin, a phenoxy resin, a linear elastomer, a surface treating agent, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  On the other hand, a magnetic material C and a magnetic material D, which are inorganic fillers, were added to the above resin components, kneaded, and finally a curing agent and a curing accelerator were added and stirred to prepare a final slurry.

  Then, the above-mentioned final slurry was applied to the surface of the polyethylene terephthalate film subjected to the mold release treatment and dried to produce a resin sheet having a thickness of 100 μm.

(Example 3)
First, a resin component was prepared by blending an epoxy resin, a phenoxy resin, a linear elastomer, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  On the other hand, the surfaces of the magnetic materials C and F, which are inorganic fillers, were treated with a coupling agent.

  Next, the above-mentioned inorganic filler after the surface treatment was added to the above-mentioned resin component and kneaded, and finally, a curing agent and a curing accelerator were added and stirred to prepare a final slurry.

  Then, the final slurry was applied to the surface of the polyethylene terephthalate film subjected to the mold release treatment and dried to produce a resin sheet having a thickness of 200 μm.

(Example 4)
First, a resin component was prepared by blending an epoxy resin, a phenoxy resin, a linear elastomer, a coupling agent, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  Next, after adding and kneading the magnetic material D which is an inorganic filler to the above resin component, kneading by adding silica which is an inorganic filler, and finally adding a curing agent and a curing accelerator and stirring the mixture. A final slurry was prepared.

  Then, the above-mentioned final slurry was applied to the surface of the polyethylene terephthalate film subjected to the mold release treatment and dried to produce a resin sheet having a thickness of 100 μm.

(Example 5)
First, a resin component was prepared by blending an epoxy resin, a phenoxy resin, a linear elastomer, a coupling agent, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  Next, after adding and kneading a magnetic material D as an inorganic filler to the above resin component, adding and kneading a magnetic material E as an inorganic filler, and finally adding a curing agent and a curing accelerator and stirring. Thus, a final slurry was prepared.

  Then, the above-mentioned final slurry was applied to the surface of the polyethylene terephthalate film subjected to the release treatment, and dried to produce a resin sheet having a thickness of 100 μm.

(Comparative Example 1)
First, a resin component was prepared by blending an epoxy resin, a surface treating agent, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  Next, a magnetic material A and a magnetic material B, which are inorganic fillers, were added to the resin component and kneaded. Finally, a curing agent and a curing accelerator were added and stirred to prepare a final slurry.

  The final slurry was applied to the surface of the release-treated polyethylene terephthalate film and dried to produce a resin sheet having a thickness of 150 μm.

(Comparative Example 2)
First, a resin component was prepared by blending an epoxy resin, a coupling agent, and a solvent so as to have the contents shown in Table 1. The solvent is the same as in Example 1.

  Next, a magnetic material C and a magnetic material F, which are inorganic fillers, were added to the above resin component and kneaded. Finally, a curing agent and a curing accelerator were added and stirred to prepare a final slurry.

  Then, the above-mentioned final slurry was applied to the surface of the polyethylene terephthalate film subjected to the mold release treatment and dried to produce a resin sheet having a thickness of 100 μm.

(Tension test of resin sheet)
In accordance with JIS K6251, a dumbbell-shaped No. 2 test piece (width of parallel portion: 10 mm) was prepared from a resin sheet.

  Based on JIS K7127, the above test pieces were subjected to a tensile test using a desktop precision universal tester “AGS-X” manufactured by Shimadzu Corporation. In the tensile test, the distance between the marked lines of the test piece was 60 mm, and the tensile speed was 10 mm / min.

  The strength at break (maximum strength) of the resin sheet and the elongation of the resin sheet at that time were measured by a tensile test. Table 1 shows the results.

(Bending test of cured resin sheet)
A plurality of resin sheets were stacked so that the thickness after curing became 1.5 mm, and heated and pressed to be integrated, and then a test piece having a width of 16 mm was produced.

  In accordance with JIS C6481, a bending test was performed on the above test piece using a desktop precision universal testing machine “AGS-X” manufactured by Shimadzu Corporation. The test piece was supported at a distance between supporting points of 23 mm, and a bending test was performed by applying a force to the center of the test piece with a pressing tool. In the bending test, the bending speed was 0.8 mm / min.

  By a bending test, the elastic modulus, bending strength and displacement amount of the test piece at the time of breaking were measured. Table 1 shows the results.

  In Comparative Examples 1 and 2, the resin sheet was torn when peeled from the polyethylene terephthalate film, and the tensile test could not be performed. From this, it was confirmed that the handleability at room temperature was poor. Moreover, the results of the bending test of the cured product confirmed that the stress relaxation was low.

  On the other hand, in Examples 1 to 5, since the resin sheet contains the phenoxy resin and the linear elastomer, the resin sheet before curing was at room temperature despite the high content of the inorganic filler. It was confirmed that both the handleability and the stress relaxation of the cured resin sheet were improved.

DESCRIPTION OF SYMBOLS 1 Resin sheet 2 Inductor component 3 Final slurry 4 Film 5 Coiled wiring 6 Resin layer

Claims (8)

A semi-cured resin sheet,
The resin sheet contains an epoxy resin, a phenoxy resin, a linear elastomer, a curing agent, and an inorganic filler,
The content of the linear elastomer is 0.01 to 0.5 parts by mass with respect to a total of 100 parts by mass of the components of the resin sheet excluding the linear elastomer,
The content of the inorganic filler is 80 to 98% by mass relative to the total amount of the resin sheet,
The inorganic filler contains two or more iron-based alloys having different average particle diameters,
A resin sheet, wherein the iron-based alloy contains a soft magnetic iron-silicon-based alloy. The resin sheet according to claim 1, wherein the iron-based alloy further includes a soft magnetic iron-aluminum-silicon-based alloy. Resin sheet according to claim 1 or 2, wherein the inorganic filler, characterized in that it is insulated. The resin sheet according to any one of claims 1 to 3 , wherein the minimum average particle diameter is 5 nm to 10 µm. The resin sheet according to any one of claims 1 to 4, wherein a maximum average particle diameter is 10 to 150 µm. The resin sheet according to any one of claims 1 to 5 , wherein the resin sheet further contains a surface treatment agent. The resin sheet according to any one of claims 1 to 6 , wherein the linear elastomer has a weight average molecular weight of 20,000 to 1,000,000 . Coiled wiring,
And a resin layer covering the coil-shaped wiring,
An inductor component, wherein the resin layer is formed of a cured product of the resin sheet according to any one of claims 1 to 7 .

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