JP2005272714A - Insulating magnetic paint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating magnetic paint of high magnetic permeability that is a magnetic paint for forming functional magnetic layers on a laminated electronic part, particularly suitable for base plate into which parts are built. <P>SOLUTION: This is an insulating magnetic paint that includes magnetic metal particles coated with an insulating coating film and a binder resin in which (i) the magnetic metal particles have a flat shape, a thickness of 0.05 to 1 μm and an aspect ratio of ≥50, (ii) the insulating film is made of metal oxide sol of one or two or more kinds selected from silica sol, titania sol, alumina sol and cerium oxide sol and the thickness of the film is 30 to 200 nm, (iii) the primary particle size of the metal oxide included in the metal oxide sol is 5 to 100 nm, and the secondary particle size is ≤200 nm and (iv) the magnetic metal particles coated with the insulating coating film are mixed in an amount of 15 to 60 volume % to the binder resin (on the solid base). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic coating material for forming a functional magnetic layer on a laminated electronic component, and more particularly to an insulating magnetic coating material suitable for a build-up method and a component-embedded substrate application.

  In recent years, with the widespread use of portable information devices (PDAs) typified by mobile phones and the like, it has been required to improve the performance and miniaturization of the components that make up PDAs. Technology is important.

  The printed circuit board serves as a support for placing a desired passive element or active element at a predetermined location of the two-dimensional wiring pattern formed on the circuit board. As a wiring pattern forming technique, a hole is formed in the printed circuit board, There are a plating through-hole method in which a conductor layer is provided on a wall surface by plating or the like, and a build-up method in which a multilayer wiring board is formed by stacking conductor layers and insulating layers one by one.

  In recent years, complicated circuit design due to the high performance of PDAs has increased not only the complexity of wiring patterns (high density and multi-layering) but also the number of parts used. There is an increasing technical demand for a component-embedded substrate on which components such as elements and active elements are simultaneously formed by printing.

  The component-embedded substrate is one of electronic components and requires high performance with respect to electrical characteristics. Among them, the coil, which is one of the passive elements, has a shape of solenoid type, spiral type, meander type, etc., is formed by a two-dimensional or three-dimensional structure, and it is important that the inductance (L) is high in circuit design. It is. In general, a high L value can be obtained in proportion to the magnetic permeability (μ), the number of turns, and the area. However, from the viewpoint of miniaturization and thinning, increasing the number of windings and the area is counterproductive, Increasing the magnetic susceptibility is an important issue.

  Coil products using a core of a high magnetic permeability material have conventionally existed, such as a chip coil component such as a type in which a coil is embedded in ferrite, a type in which a magnetic thin film is wound (see, for example, Patent Document 1), Inductors and transformers (for example, see Patent Documents 2 and 3) in which a soft magnetic thin film is produced by a sputtering method or the like have been proposed, but these are not component sizes and manufacturing methods suitable for the build-up method. The above-mentioned Patent Document 1 discloses a multilayer type thin inductor, but uses an oxide core material, and the high permeability material is lower than that of a soft magnetic metal material.

  In addition to the above documents, Patent Document 4 proposes an electromagnetic shielding material in which silica or alumina powder is bonded to the surface of magnetic metal particles to enhance insulation and take measures against eddy currents. .

JP-A-5-275247 JP-A-5-101930 JP-A-6-316748 JP 2002-368480 A

  In general, a needle-like or flat-shaped soft magnetic metal material using shape magnetic anisotropy is preferable as the high magnetic permeability material, but there are various problems as described below in applying these to the build-up method.

  In order to use it in an RF circuit, it is necessary to have a high magnetic permeability in a high frequency band. However, since a metal material has a low electric resistance, loss due to an eddy current occurs in the high frequency band, and the magnetic permeability tends to decrease. There is. Further, if a magnetic layer is provided so as to be in contact with the wiring pattern of the printed circuit board, there is a problem that the wiring is short-circuited. Therefore, as an insulation evaluation, the insulation resistance of the inner layer is defined in JIS C 5012. A DC voltage of 10 ± 1 V is applied for 1 minute between the wirings of the comb-type wiring pattern, and the insulation can be achieved without breakdown. It is necessary to have.

  Measures to cope with this include a method for improving the metal material composition by adding an element for improving the insulation property to the composition of the metal material, and a method for imparting insulation by oxidizing the surface of the magnetic metal particles. . However, these tend to greatly reduce the magnetic properties.

  Further, in the method for producing an electromagnetic shielding material by coating the surface of magnetic metal particles with silica or alumina powder described in Patent Document 4, the coating treatment is electrostatically coupled, The binding force between magnetic metal particles and silica powder is not sufficient. Therefore, when kneading with the resin, problems such as separation of the coating film occur, it is difficult to ensure sufficient insulation between the wirings, and the filling property and orientation in the resin are likely to be impaired.

  Furthermore, since the build-up method forms a pattern while laminating, the surface smoothness of the coating film is also required. In general, coarse particles such as ferrite powder are used for electronic parts. However, the coating film surface formed by mixing such coarse particles with a binder tends to be rough and is not suitable for lamination.

  Thus, in order to form a high permeability magnetic film using a magnetic metal material, it is important to achieve both insulation and high permeability.

  The present invention solves these conventional problems, and is particularly suitable for the build-up method and further for use in a component-embedded substrate, and is a magnetic layer composed of magnetic metal particles and a resin capable of achieving both insulation and high magnetic permeability. An object of the present invention is to provide an insulating magnetic paint for forming the film.

In order to solve the above problems, the present invention is an insulating magnetic paint containing magnetic metal particles coated with an insulating film and a binder resin, and the following conditions (i) to (iv):
(I) The magnetic metal particles have a flat shape, a thickness of 0.05 to 1 μm, an aspect ratio of 50 or more,
(Ii) The insulating coating is a coating derived from a metal oxide sol containing one or more selected from silica sol, titania sol, alumina sol, and cerium oxide sol, and the thickness of the coating is 30 to 200 nm. And
(Iii) The primary particle size of the metal oxide contained in the metal oxide sol is 5 to 100 nm, the secondary particle size is 200 nm or less,
(Iv) Magnetic metal particles coated with an insulating film are blended in a proportion of 15 to 60% by volume with respect to the binder resin (solid content).
An insulating magnetic paint that satisfies the above requirements is provided.

  The present invention also provides the above insulating magnetic paint, wherein the magnetic metal particles have a maximum particle size of 100 μm or less.

  In addition, the present invention uses a metal organic compound in which the insulating film can form a hydroxyl group by hydrolysis, so that an -O-Me-O- bond (Me: included in the metal organic compound) is formed on the surface of the magnetic metal particle. The insulating magnetic paint is coated via a metal.

Here, the metal organic compound is Me (RO) _m (R) _n (where Me represents a metal element of Si, Ti, Zr, or Al, and R represents an alkyl group having 1 to 8 carbon atoms). M + n represents a number equal to the valence of Me, m represents a number of 2 or more, and n represents 0 or a number of 1 or more), or Me (RO) _m (Y) _n (where Me, R, m + n, m and n are as defined above, respectively, and Y is a hydrocarbon group having 1 to 12 carbon atoms, amino group, epoxy group, vinyl group, acrylic group, methacrylic group) It is preferably one or more selected from coupling agents represented by an organic functional group selected from a group or an alkyl acetate.

  According to the present invention, a high magnetic permeability can be obtained as compared with a ferrite-based oxide magnetic material, and both good magnetic properties and insulating properties can be achieved. Therefore, in manufacturing a component built-in substrate or the like, it is possible to form a high permeability magnetic film directly on the conductive pattern. Since it has high magnetic permeability, it can be used as a core material of a coil element or an electromagnetic wave shielding layer. In addition, because the particle size and pigment volume concentration are optimized, it has excellent adhesion to the substrate, high surface smoothness of the coating film, and is suitable for a laminated structure. It is possible.

  The present invention is described in detail below.

  The insulating magnetic paint according to the present invention contains magnetic metal particles coated with an insulating film and a binder resin.

  The magnetic metal particles are not particularly limited, but magnetic metal particles mainly composed of Fe, Ni, or Co are preferably used. Further, as a metal element for improving corrosion resistance, Mo, Mn, Cu, Al, Si, One or more elements such as Cr and W may be contained in the metal composition. Specific examples of such magnetic metal particles include Sendust, silicon steel, and permalloy.

  The magnetic metal particles have a flat shape. The method of flattening the magnetic metal particles can be obtained by, for example, producing spherical particles by a method typified by an atomizing method and the like, and pulverizing and flattening the particles with an attritor or the like. It is not limited to.

  In the present invention, the magnetic metal particles have an aspect ratio of 50 or more and a thickness of 0.05 to 1 μm. By setting the aspect ratio and thickness of the particles within the above ranges, high magnetic permeability can be obtained.

  The magnetic metal particles preferably have an average particle size of 10 to 50 μm and a maximum particle size of 100 μm or less.

  The flat-shaped magnetic metal particles are less affected by the demagnetizing field in the in-plane direction due to the shape magnetic anisotropy, and can obtain a high permeability. When a coating material dispersed in a binder resin is formed, the flat-shaped magnetic metal particles The magnetic metal particles are oriented in the plane so as to be stacked in the film, and the magnetic permeability in the in-plane direction can be increased. Furthermore, by using an external magnetic field when forming a coating, it is possible to uniformly align the flat magnetic metal particles within the film surface, increasing the surface smoothness of the magnetic layer and forming a laminated structure. It is easy and has the effect of suppressing characteristic variations. When an external magnetic field is used, it can be oriented vertically or obliquely, and a high permeability film can be functionally formed in accordance with the coil design.

  The insulating coating for coating the magnetic metal particles is a coating derived from a metal oxide sol containing one or more selected from silica sol, titania sol, alumina sol, and cerium oxide sol.

  The method for forming the insulating film derived from the oxide sol is not particularly limited. From the viewpoint of improving the magnetic properties, a metal organic compound capable of forming a hydroxyl group by hydrolysis on the particle surface of the magnetic metal particle is used. And one kind selected from silica sol, titania sol, alumina sol, and cerium oxide sol via a —O—Me—O— bond (Me: a metal contained in the metal organic compound) on the surface of the magnetic metal particles. It is most preferable to coat with an insulating film derived from a metal oxide sol containing two or more kinds.

  As said metal organic compound, what can form a hydroxyl group by hydrolysis is used. In the present invention, those which can be hydrolyzed by reaction with a lower alcohol or water / lower alcohol solvent to form a hydroxyl group are preferably used. Examples of such metal organic compounds include metal alkoxides, coupling agents, metal cetyl acetonates, metal carboxylates and the like. Of these, metal alkoxides and coupling agents are preferably used because they are highly reactive and easily produce a polymer composed of a metal-oxygen bond.

As the metal alkoxide, Me (RO) _m (R) _n (where Me represents a metal element of Si, Ti, Zr, Al, R represents an alkyl group having 1 to 8 carbon atoms, m + n represents a number equal to the valence of Me, m represents a number of 2 or more, and n represents a number of 0 or 1). That is, the metal alkoxide having at least two alkoxy groups is preferably used. Note that as the number of alkoxy groups (RO) in one molecule increases and the carbon chain is shorter, the bonding force between the metal particles and the metal oxide sol can be increased, and the reactivity can be increased. In the above formula, since the alkoxy group (RO) is a short chain (1 to 8, preferably 1 to 4 carbon atoms), the bonding force between the metal particles and the metal oxide sol (described later) is enhanced, and the reaction This is preferable because the properties can be improved. N is preferably 0.

Specific examples of such metal alkoxides include Si-based alkoxides such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , CH ₃ Si (OCH ₃ ) ₃ , and CH ₃ Si (OC ₂ H ₅ ) ₃ . Ti-based alkoxides such as Ti (OC ₃ H ₇ ) ₄ , Ti (OC ₄ H ₉ ) ₄ , (OC ₄ H ₉ ) ₃ Ti—Ti (OC ₄ H ₉ ) ₃ , Zr (OC ₃ H ₇ ) ₄ Zr-based alkoxides such as Zr (OC ₄ H ₉ ) ₄ and Al-based alkoxides such as Al (OC ₃ H ₇ ) ₃ and Al (OC ₄ H ₉ ) ₃ are exemplified, but are limited to these examples. It is not a thing.

As the coupling agent, Me (RO) _m (Y) _n (where Me, R, m + n, m, and n are as defined above, respectively, and Y is a hydrocarbon having 1 to 12 carbon atoms. An organic functional group selected from a group, an amino group, an epoxy group, a vinyl group, an acrylic group, and a methacryl group, or an alkyl acetate) is preferably used.

  Examples of the coupling agent include Al coupling agents such as alkyl acetoacetate aluminum diisopropylate, and silane cups such as γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Examples include ring coupling agents, Ti coupling agents such as titanium acetyl acetate and titanium ethyl acetate, Zr coupling agents such as zirconium dibutoxybis (acetylacetonate) and zirconium tributoxyethyl acetoacetate. It is not limited to.

  The production of the metal alkoxide is not particularly limited, and a metal alkoxide obtained by a conventional method such as bringing a metal and an alcohol into contact with each other can be used.

  The metal oxide sol used in the present invention is preferably a dispersion in which one or more metal oxides selected from silica sol, titania sol, alumina sol, and cerium oxide sol are dispersed in a solvent. The specific metal oxide sol is particularly preferable for obtaining insulation.

  As the metal oxide sol, a metal oxide sol having a smaller particle diameter can form a denser film, so that a primary particle size of 5 to 100 nm is preferably used, and preferably 5 to 20 nm. In addition, it is preferable to use a secondary particle size of 200 nm or less, preferably 50 nm or less. If the primary particles of the metal oxide are larger than 100 nm and the secondary particles are larger than 200 nm, the adhesion of the insulating film tends to be reduced, and it becomes difficult to form a uniform film. The surface of the metal oxide sol preferably has a large number of hydroxyl groups in order to bond strongly with the alkoxy group of the metal alkoxide.

  The production of the metal oxide sol is not particularly limited, and a product obtained by, for example, dispersing a hydrolyzed / condensed metal alkoxide as a starting material by a sol-gel method in a dispersion medium is preferably used. And the number of hydroxyl groups on the surface of the metal oxide sol can be increased. As the dispersion medium, water, lower alcohol or the like is preferably used, and water is particularly preferable. However, it is not limited to this.

  The insulation-coated metal particles according to the present invention are preferably produced by the following production method, but are not limited to this method.

[Hydrolysis / adsorption (bonding) process]
First, metal particles are dispersed in a solvent, and a solution is prepared by adding the metal organic compound (hereinafter, metal alkoxide will be described as a representative example) and a metal oxide sol.

  As the solvent, a solvent that does not significantly impair the dispersibility of the metal particles, the metal alkoxide, and the metal oxide sol is used. In the present invention, a water / alcohol solvent containing water and a lower alcohol such as methanol, ethanol or isopropanol can be preferably used.

  The metal particles are preferably washed beforehand by acid treatment or the like. Examples of acids that can be used include inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid, and organic acids such as organic carboxylic acids. For example, a 5% hydrochloric acid aqueous solution is kept constant at a liquid temperature of 20 ° C., and the metal magnetic powder is kept at an appropriate time. After the immersion, a method of removing the cleaning liquid with a filter and further washing with water can be used, but the method is not limited to this.

  Subsequently, the acid-treated metal particles are dispersed in a water / alcohol solvent. The metal particles can be dispersed by a bead mill or ultrasonic dispersion, but is not limited to these methods. The metal particles are preferably added to the water / alcohol solvent in an amount of about 5 to 50% by mass, more preferably about 10 to 30% by mass. After the metal particles are dispersed in the primary particles in this manner, the metal alkoxide and the metal oxide sol are added.

  The metal alkoxide is preferably added at a ratio of 0.05 to 30% by mass, particularly 0.1 to 10% by mass with respect to the metal particles. If the addition amount of the metal alkoxide is too small, the bonding strength of the metal oxide sol is weak and a phenomenon such as detachment of the oxide film is likely to occur. There is a tendency for the aggregates to be firmly formed, which is not preferable.

  The metal oxide sol is preferably added at a ratio (solid content ratio) of 1.0 to 30% by mass, particularly 1.5 to 15% by mass with respect to the metal particles. If the addition amount of the metal oxide sol is too small, a phenomenon such as poor insulation (breakdown, etc.) is likely to occur. On the other hand, if the addition amount is excessive, the metal sol There is a tendency to remarkably reduce the characteristics (for example, magnetic characteristics), and this is not preferable.

  Subsequently, the solution in which the metal particles, the metal alkoxide, and the metal oxide sol are added in the solvent is uniformly stirred. The stirring time may be about several minutes and is not particularly limited. The liquid temperature is preferably about 20 to 60 ° C. from the viewpoint of controlling the reaction rate.

  Next, after adjusting the pH of the solution to 3 to 4, the solution is stirred and allowed to stand.

  In the above series of treatments, first, the metal alkoxide is hydrolyzed. By hydrolysis of the metal alkoxide, the alkoxy group of the metal alkoxide becomes a hydroxyl group. The hydroxyl group derived from the metal alkoxide is adsorbed in a hydrogen bond manner with the hydroxyl group on the surface of the metal particle or the metal oxide sol. More specifically, the hydroxyl group derived from the metal alkoxide is adsorbed on an active site on the surface of the metal particle to form a (metal particle-OHHO-Me-OR) bond, or subsequently formed sequentially. Among them, other hydroxyl groups are adsorbed on the metal oxide sol to form a (metal oxide sol-OHHO-Me-OR) bond. These then condense (metal particles-OHHO-Me-OHHO-metal oxide sol) to form a bond.

  The hydrolysis treatment time varies depending on the metal organic compound species (metal species, alkyl group species, alkoxy group species), the pH and temperature of the solution, the ratio of water to alcohol in the solution, etc., but is usually 1 to 3 hours. Finish with a degree.

  At this time, some hydroxyl groups derived from the metal alkoxide condense with other hydroxyl groups derived from the metal alkoxide in the process of adsorbing with the metal particles or metal oxide sol, resulting in non-uniform oligomerization in the solution. there's a possibility that. The increase in the molecular weight of the oligomer may be disadvantageous for uniformly coating the metal particles with the metal oxide sol and strongly binding them. Therefore, when hydrolyzing the alkoxy group of the metal alkoxide, the dehydration / condensation reaction between the hydroxyl groups can be suppressed, the hydroxyl group can be stably maintained without causing such a reaction, and the above binding / adsorption can be promoted. It is suitable for uniformly treating metal particles with a metal oxide sol.

  Such dehydration / condensation reaction can be suppressed by adjusting the pH of the solution, and the reaction is most suppressed at pH 3-4. Thereby, the adsorption of the hydroxyl group derived from the metal alkoxide to the metal particles and the adsorption (bonding) to the metal oxide sol can be performed stably.

  In addition, pH adjustment can be performed by adding an acid etc., for example. The acid is not particularly limited, and for example, organic acids such as acetic acid and organic carboxylic acids, inorganic acids such as hydrochloric acid, phosphoric acid, hydrochloric acid, and sulfuric acid can be used, but the acid is not limited to these examples.

[Dehydration and condensation reaction acceleration process]
After the hydrolysis / adsorption (bonding) step, the dehydration / condensation reaction of the solution is promoted to bond (metal particle-OHHO-Me-OHHO-metal oxide sol) bond to (metal particle-O-Me-O). -Metal oxide sol) bond. As a result, the metal particles and the metal oxide sol are firmly bonded (adsorbed) via the —O—Me—O bond (metalloxane bond).

  The dehydration / condensation reaction rate can be promoted by changing the pH 3 to 4 solution to a value of pH 2 or higher. Specifically, for example, the pH 3 (~ 4) solution is adjusted to pH 5 (~ 6) or higher, or the pH 3 (~ 4) solution is adjusted to pH 1 (~ 2) or lower. it can. The greater the change in pH value, the higher the effect. Therefore, considering only the point of increasing the dehydration / condensation reaction rate, it can be promoted particularly effectively by bringing the pH closer to 1 or 14. The pH can be adjusted by acid addition or alkali addition.

  However, since it is considered that the metal particles corrode with strong acid or strong alkali, it is necessary to select various pH values and pH adjusters to be changed. If the pH adjuster is added rapidly, the condensation reaction tends to occur non-uniformly in the treatment liquid, so it is desirable to add gradually while stirring.

  In the dehydration / condensation reaction step, it is desirable to add a coupling agent or surfactant having an alkyl group having a large number of carbon atoms to the treatment liquid so as not to form an aggregate due to excessive dehydration / condensation. For example, decyltrimethoxysilane or amine surfactant can be used. In particular, a surfactant of polyoxyethylene (POE) coconut alkylamine has an effect of preventing aggregation.

  Although it is possible to produce metal particles coated with a metal oxide sol without using such pH adjustment or aggregate prevention material, the uniformity of the film and the stability (reproducibility) of the insulation resistance value It becomes good.

[Filtering, drying, heat treatment process]
The solution after the dehydration / condensation step is filtered with a filter or the like, and the treated powder is dried with a heat treatment furnace or the like. In addition, it is desirable that the liquid part in which the dehydration / condensation reaction is not completed is completely completed by heat treatment. The heat treatment temperature is preferably 100 ° C. or higher, and it is necessary to adjust the temperature and time so that the oxidation of the metal particles does not proceed.

  The dehydration / condensation reaction can be promoted by drying / heat treatment to obtain insulating coated metal particles coated with a strongly bonded metal oxide sol-derived coating.

  The thickness of the insulating film is preferably controlled to be 10 to 200 nm. At this time, the saturation magnetization of the untreated magnetic metal particles and the magnetic metal particles subjected to the insulation coating treatment is measured, and the amount of treatment can be quantified from the rate of decrease in magnetization. When the thickness of the insulating coating is 10 nm or less, the insulation is insufficient, and when it is 200 nm or more, a magnetic layer with good permeability cannot be obtained.

  Next, the magnetic metal particles subjected to insulation coating are dispersed in a binder resin to prepare a paint. As a dispersion method, the magnetic metal particles and the binder resin are uniformly dispersed in a paint solvent. As a disperser, a bead mill, Henschel, a kneader, or the like can be used, and magnetic metal particles that are insulation-coated in accordance with various methods are used under optimum conditions that facilitate dispersion in the resin.

  As the binder resin, known resins such as silicone, styrene, acrylic, xylene, phenol, polyester, urethane, epoxy, bismaleimide triazine, polyethersulfone, polyimide, and other thermoplastic resins, thermosetting resins, and UV curable resins are known. The resins can be used alone or in admixture of two or more. In addition, various solvent-soluble types, emulsion types, dispersion types as resin beads, etc. can be used as the form of the resin, although it is not particularly limited, since the production of a printed circuit board by the build-up method has a multilayer structure, In order to prevent cracks and delamination for a long time after lamination, it is preferable to select a material having a linear expansion coefficient close to each layer.

  The compounding ratio of the binder resin and the magnetic metal particles coated with insulation greatly affects the cohesive strength of the magnetic film, adhesion at the interface during lamination, magnetic properties of the magnetic layer, and insulation. Therefore, the pigment volume concentration is adjusted to 15 to 60% by volume. When the compounding ratio is less than 15% by volume, good magnetic properties of the magnetic layer cannot be obtained. On the other hand, when the blending ratio is more than 60% by volume, there is a problem that the cohesive strength of the magnetic layer is lowered and the adhesive strength with the base is lowered.

  The coating solvent in the present invention is not particularly limited, and specific examples include alcohols such as water, methanol, ethanol, propanol, butanol, amyl alcohol, hexanol, heptanol, octanol, decanol, ethyl ether, isopropyl ether, and methylphenyl. Ethers such as ether, epichlorohydrin, trioxane, furfural, tetrahydrofuran, cineol, etc., ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, phorone, cyclohexanone, acetophenone, dipnon, methyl formate, methyl acetate, methyl propionate, methyl butyrate, lactic acid Esters such as methyl, diethyl oxalate, dimethyl phthalate, polyhydric alcohols such as ethylene glycol, benzene, toluene Xylene, organic solvents such as hydrocarbons such as cyclohexane may be used. Selection is made according to the film forming method, dispersibility, storage stability, safety, and the like.

  In the present invention, in order to improve dispersibility, the magnetic metal particles coated with insulation may be further surface-modified with various coupling agents. Various additives may be added to the paint. A dispersant, a thickener, an antioxidant, an antifoaming agent, a polymerization agent, a curing agent, a curing catalyst, etc. may be used alone or in combination of two or more. May be used.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Unless otherwise specified, the blending amount is expressed in mass% with respect to the system in which the component is blended.

(Example 1)
Fe-Ni flat metal magnetic powder (permalloy powder) having an average particle diameter of 20 μm and a thickness of 0.1 μm was used as the magnetic metal particles. Permalloy powder is immersed in a 5% aqueous hydrochloric acid solution (liquid temperature 20 ° C.) for 30 minutes, filtered, washed with water, acid washed, and 10 g added to 100 mL of a mixed solution of isopropyl alcohol and water (5: 5 (mass ratio)). And stirred for 10 minutes with an ultrasonic disperser.

  Next, 0.8 g of tetramethoxysilane (KBM-04, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and silica sol (PL-1L, manufactured by Fuso Chemical Co., Ltd.) having primary particles dispersed in water was further solidified. 1 g was added in minutes and stirred for 5 minutes.

  After stirring, acetic acid was added to adjust the pH of the solution to 4 to prepare a treatment solution. After stirring the treatment liquid at a constant temperature of 25 ° C. for 2 hours, ammonia was gradually added while stirring to adjust the pH to 7. The treatment liquid produced by the above method is filtered to remove the solvent, the treated powder is taken out, washed with water, filtered again, and then heat-treated and dried at 120 ° C. for 2 hours to obtain an insulation coating metal with an insulation film thickness of 50 nm. Particles were made.

  Dispersant (AMIET105, manufactured by Kao Corporation) was added to 100 g of the insulating coated metal particles produced by the above method in an amount of 1 mass% with respect to the mass ratio of the insulating coated metal particles, and methyl isobutyl ketone and toluene (5: 5 ( 30% in a paint shaker (500 mL container, using φ2 mm steel beads) together with a mixed solvent of (mass ratio)) and an epoxy resin (PCE-57, manufactured by Nippon Pernox Co., Ltd.) solution adjusted to 30% with the solvent. Dispersion was performed. At this time, the amount of the epoxy resin was adjusted, and different magnetic paints having a volume content of the insulating coating metal particles with respect to the solid content of the epoxy resin of 10 to 80% by volume were prepared (see sample Nos. 1 to 5 in Table 1 below). .

  The obtained magnetic coating material was applied on a substrate with an applicator so as to have a dry film thickness of 20 μm, subjected to orientation treatment with an external magnetic field (1.0 kG), and then thermally cured at 160 ° C. for 60 minutes, and an evaluation sample Was made. As the substrate, a double-sided glass epoxy substrate with a Cu foil (32, manufactured by Sanhayato Co., Ltd.) and a PET film were used. The glass epoxy substrate with Cu foil was formed after the surface was roughened by chemical immersion. When the film is formed on the Cu foil surface, the Cu foil surface is roughened with a soft etching solution (OPC-480, manufactured by Okuno Pharmaceutical Co., Ltd.), and when the film is formed on the glass epoxy surface, the glass epoxy surface is permanganese. It was roughened with a potassium acid etching solution (OPC-B201, manufactured by Okuno Pharmaceutical Co., Ltd.).

  The evaluation sample was used to evaluate the adhesion to the substrate and the effective magnetic permeability. Adhesion with the substrate was performed by a tape peeling test (conforming to JIS K5600-5-6), and a sample formed on a PET film was subjected to an impedance analyzer (E4991A, manufactured by Agilent Technologies) with a frequency (f) of 100 MHz. The effective relative permeability of was measured. The results are shown in Table 1.

  As is clear from the results in Table 1, the magnetic properties improve as the volume content of the insulating coated metal particles increases. In 2 to 4, a magnetic film having good adhesion and magnetic properties was obtained. In contrast, sample no. 1 cannot obtain good magnetic properties of the magnetic film. In No. 5, the cohesive force of the magnetic film was reduced, and the adhesion with the substrate was reduced.

(Example 2)
As magnetic metal particles, Fe-Ni flat metal magnetic powders (permalloy powders) having different particle diameters shown in Table 2 below are used (see sample Nos. 6 to 10 in Table 2 below), and the same method as in Example 1 is used. Insulation-coated metal particles were produced. A screen ink having a viscosity of 3000 to 4000 cP was prepared in the same manner as in Example 1 using isophorone as the solvent.

  The above ink was printed by screen printing so as to have a dry film thickness of 20 μm, and the printed body was subjected to an orientation treatment with an external magnetic field (1.0 kG), and then subjected to a heat treatment at 160 ° C. for 60 minutes. At this time, two types of printed patterns, a solid film of 0.5 × 0.5 mm, and a donut pattern having an outer diameter of 20 mm and an inner diameter of 10 mm were prepared and used as evaluation samples.

  The evaluation sample uses a solid film with a printed pattern of 0.5 × 0.5 mm, and the center line roughness (Ra) is evaluated with a surface roughness meter (Surfcom 550A, manufactured by Toyo Seimitsu Co., Ltd.). The outer diameter is 20 mm and the inner diameter is 10 mm. The effective relative magnetic permeability at a frequency (f) of 100 MHz was measured with an impedance analyzer using the donut pattern. The evaluation results are shown in Table 2.

  As is clear from the results in Table 2, the sample No. Nos. 6 to 8 had good magnetic properties and surface smoothness. Sample No. No. 9 had poor magnetic properties and surface smoothness, and the magnetic properties were poor. Sample No. No. 10 had a small particle size and good surface smoothness, but good magnetic properties were not obtained.

(Example 3)
In the same manner as in Example 1, the amount of addition was adjusted using silica sol having each particle size (see Sample Nos. 11 to 17 in Table 3 below) to prepare various insulating coated metal particles shown in Table 3 below. A screen ink was prepared in the same manner as in Example 2.

  The ink was printed on a comb-type wiring pattern with a Cu wiring width of 100 μm and a wiring interval of 100 μm by screen printing so as to have a dry film thickness of 20 μm, oriented by an external magnetic field, and heat-treated at 200 ° C. for 30 minutes. In addition, the same ink is printed on a PET substrate by screen printing so as to have a dry film thickness of 10 μm, subjected to orientation treatment with an external magnetic field (1 kG), and then subjected to thermosetting at 160 ° C. for 60 minutes to obtain an evaluation sample. Produced.

  The coating thickness of the insulating coating metal particles is determined by measuring the saturation magnetization of untreated metal magnetic particles with a vibrating sample magnetometer (VSM), and determining the thickness of the insulating coating from the density of the oxide sol used and the rate of decrease in saturation magnetization. Was estimated. Using a sample printed on the comb-shaped wiring pattern, a voltage of DC 10 V was applied between the wirings by a resistance measuring device (MILLI-TO 2, manufactured by MONROE ELECTRONICS INC), and the insulation resistance was measured. Further, the effective relative permeability at a frequency of 100 MHz was measured with an impedance analyzer using a sample printed on PET. The results are shown in Table 3.

  As is apparent from the results in Table 3, the sample No. Nos. 11 to 14 were able to obtain high insulation and good magnetic properties. Sample No. No. 15 had a thin insulating film and broke down when a DC voltage of 10 V was applied between the wirings of the comb wiring pattern. Sample No. No. 16 uses a silica sol having a large particle size, but since the insulating film is thin, the density of the insulating specific film is low and the cohesive force is small. Characteristics were not obtained. Sample No. Since No. 17 used a silica sol having a large particle diameter, good results were not obtained in both insulation and magnetic properties.

  The insulating magnetic paint according to the present invention is suitably applied to the manufacture of electronic components manufactured by a build-up method and component-embedded substrates in the field of semiconductor manufacturing.

Claims (4)

An insulating magnetic paint comprising magnetic metal particles coated with an insulating film and a binder resin, wherein the insulating magnetic paint satisfies the following conditions (i) to (iv):
(I) The magnetic metal particles have a flat shape, a thickness of 0.05 to 1 μm, an aspect ratio of 50 or more,
(Ii) The insulating coating is a coating derived from a metal oxide sol containing one or more selected from silica sol, titania sol, alumina sol, and cerium oxide sol, and the thickness of the coating is 30 to 200 nm. And
(Iii) The primary particle size of the metal oxide contained in the metal oxide sol is 5 to 100 nm, the secondary particle size is 200 nm or less,
(Iv) Magnetic metal particles coated with an insulating film are blended at a ratio of 15 to 60% by volume with respect to the binder resin (solid content).   The insulating magnetic paint according to claim 1, wherein the maximum particle size of the magnetic metal particles is 100 μm or less.   By using a metal organic compound in which the insulating film can form a hydroxyl group by hydrolysis, the surface of the magnetic metal particle is bonded to the surface of the magnetic metal particle via a —O—Me—O— bond (Me: metal contained in the metal organic compound). The insulating magnetic paint according to claim 1, wherein the insulating magnetic paint is coated. The metal organic compound is Me (RO) _m (R) _n (where Me represents a metal element of Si, Ti, Zr or Al, R represents an alkyl group having 1 to 8 carbon atoms, m + n Represents a number equal to the valence of Me, m represents a number of 2 or more, and n represents a number of 0 or 1), or Me (RO) _m (Y) _n (however, , Me, R, m + n, m, n are as defined above, and Y is selected from a hydrocarbon group having 1 to 12 carbon atoms, an amino group, an epoxy group, a vinyl group, an acrylic group, and a methacryl group. The insulating magnetic coating material according to claim 3, which is one or more selected from coupling agents represented by: an organic functional group or an alkyl acetate.