JP2001189535A - Composite magnetic material substrate and prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite magnetic substrate having a low dielectric constant and a low dielectric dissipation factor and a prepreg, to provide a high heat-resistant composite magnetic substrate having high glass transition point and decomposition starting-point temperature and the prepreg, to provide the composite magnetic substrate, in which the changes of the dielectric constant and the dielectric dissipation factor are reduced, and the prepreg, to provide the composite magnetic substrate, which is superior in adhesion with a metallic foil such as a copper foil and is thin and can be manufactured by a normal substrate fabrication process, and the prepreg, to provide the composite magnetic substrate having a constant permittivity up to a frequency band in GHz and the prepreg and to provide the composite magnetic substrate having the small temperature dependence of the dielectric constant and the prepreg. SOLUTION: The composite magnetic material substrate in which magnetic powder is dispersed to a polyvinylbenzyl ether compound is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg and a substrate used for an electronic component or a circuit board, and is particularly suitable for use in a high frequency region (100 MHz or more).
The present invention relates to a prepreg and a substrate suitable for use utilizing magnetic properties and for use for magnetic shielding.

[0002]

2. Description of the Related Art Conventionally, as a substrate material used for electronic parts and circuit boards, there is a material obtained by kneading a molding material by kneading ferrite powder and subjecting the molded plate to a treatment such as plating. There is one using a composite ferrite substrate made of a composite ferrite molding material containing a polymer and ferrite as components. Further, there is a copper-clad laminate using a prepreg composed of a glass cloth-containing epoxy resin or a phenol resin containing no ferrite powder.

[0003] However, it is difficult to form a thin and large shape in the above-mentioned formed plate which has been subjected to a treatment such as plating. In the copper-clad laminate containing no ferrite powder, no magnetic material is present. Therefore, ferrite material is applied or bulk ferrite is attached to elements, components, and circuits using magnetic characteristics. There is a need. Further, it has no magnetic shielding effect by itself, and is not suitable for use for the purpose of magnetic shielding.

On the other hand, Japanese Patent Application Laid-Open (JP-A) No. 58-158813 discloses "a laminate for electric use in which a laminate base material is impregnated with a laminate resin containing a metal oxide having both magnetism and electrical insulation properties. Board "is disclosed. However, what is shown in the examples is a combination of phenolic resin and kraft paper, which is disadvantageous in strength required for thinning and heat resistance. In addition, the ratio of ferrite powder is 50 wt.
%, The magnetic properties required as a magnetic material may not be sufficiently obtained.

Japanese Patent Application Laid-Open No. Sho 59-176035 discloses a fiber composite comprising a plurality of fiber layers which are arranged one above the other and are connected and aligned with each other by a base material comprising a resin and a curing agent, and absorb electromagnetic waves. In the material, a fiber composite material in which a filler absorbing radio waves is contained in each layer from the outside to the inside with a change in concentration is disclosed. However, as shown in the example, the distribution of the packing material has a concentration gradient, and it takes time and effort to prepare the prepreg.

[0006] Further, Japanese Patent Application Laid-Open No. 2-10040 discloses a copper-clad laminate formed by laminating a prepreg obtained by impregnating and drying a thermosetting resin on a glass fiber woven fabric and forming a copper foil by heating and pressing. A copper-clad laminate for radio wave absorption, in which a radio wave absorbing material is mixed and dispersed in the thermosetting resin to absorb electromagnetic noise of a specific frequency, is disclosed. However, what is shown in the example uses PZT powder, and is not suitable for use utilizing magnetic properties or use for the purpose of magnetic shielding.

[0007] JP-A-11-192620 discloses that
`` A glass cloth, a prepreg obtained by impregnating a slurry obtained by kneading a ferrite powder and an epoxy resin in a solvent and forming a slurry, and a composite magnetic substrate obtained by heating and pressing the prepreg '' It has been disclosed. However, this prepreg has a high dielectric constant of an epoxy resin as a base, and when used as a composite magnetic substrate, the dielectric constant and the dielectric loss tangent of the substrate become high. In addition, the water absorption rate is relatively high,
For this reason, there has been a problem that a pattern peeling phenomenon easily occurs in a solder flow, a dip process, and the like, and a dielectric constant and a dielectric loss tangent are also easily changed.

Japanese Patent Application Laid-Open No. 10-79593 discloses "prepreg and printed wiring board obtained by impregnating a glass cloth with a magnetic paint comprising a soft magnetic powder and a thermosetting resin". However, this prepreg also has a high dielectric constant of an epoxy resin serving as a base, and when used as a composite magnetic substrate, the dielectric constant and the dielectric loss tangent of the substrate become high.
In addition, the water absorption rate is relatively high, and therefore, there has been a problem that a pattern peeling phenomenon easily occurs in a solder flow, a dip step, and the like, and a dielectric constant and a dielectric loss tangent easily change.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to
(1) To provide a composite magnetic substrate and a prepreg having a low dielectric constant and a low dielectric loss tangent; (2) To provide a high heat resistant composite magnetic substrate and a prepreg having a high glass transition point and a decomposition starting temperature; and (3) To provide a low water absorption. A composite magnetic substrate and a prepreg with a small change in dielectric constant and dielectric tangent in terms of ratio, and (4) excellent adhesion to a metal foil such as a copper foil, and which is thin and can be manufactured by a normal substrate manufacturing process. Provided are a substrate and a prepreg, (5) a composite magnetic substrate and a prepreg whose dielectric constant and dielectric tangent are constant up to a frequency band of GHz, and (6) a composite magnetic substrate with little temperature dependence of the dielectric constant and dielectric tangent. And to provide a prepreg.

[0010]

The above object is achieved by the present invention described below. (1) A composite magnetic substrate in which a magnetic powder is dispersed in a polyvinyl benzyl ether compound. (2) The composite magnetic substrate of the above (1), wherein the polyvinyl benzyl ether compound is represented by the following general formula (1).

[0011]

Embedded image

(Wherein, R ¹ represents a methyl group or an ethyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ³ represents a hydrogen atom or a vinylbenzyl group (provided that The molar ratio of hydrogen atom to vinylbenzyl group is 6
0:40 to 0: 100), and n represents a number of 2 to 4). (3) The composite magnetic substrate according to (1) or (2), wherein the magnetic powder is a ferromagnetic metal or ferrite. (4) The composite magnetic substrate according to any one of (1) to (3), wherein the particle diameter of the magnetic powder is 0.01 to 100 μm. (5) The composite magnetic substrate according to any one of (1) to (4), wherein the content of the magnetic powder is 50 to 90 wt%. (6) A prepreg obtained by applying a slurry in which a polyvinyl benzyl ether compound and a magnetic powder are dispersed in a solvent to a glass cloth and drying the slurry. (7) A prepreg obtained by applying a slurry in which a polyvinyl benzyl ether compound and a magnetic powder are dispersed in a solvent to a metal foil and drying the slurry. (8) A substrate obtained by heating and press-pressing the prepreg of (6). (9) A substrate with a double-sided metal foil obtained by arranging metal foils on both sides of the prepreg of (6) above and heating and pressing the metal foils. (10) A substrate with a double-sided metal foil obtained by arranging the prepreg of (7) above on both sides of a glass cloth with the metal foil side facing out, and pressing this under heat and pressure. (11) A prepreg obtained by kneading a polyvinyl benzyl ether compound and a magnetic powder at least at a temperature equal to or higher than the melting point of the polyvinyl benzyl ether compound, and press-molding the solid kneaded material. (12) A substrate obtained by heating and pressing the prepreg of (11) above. (13) A substrate with a double-sided metal foil obtained by arranging metal foils on both sides of the prepreg of the above (11) and pressing the metal foils under heat and pressure. (14) A multilayer substrate obtained by laminating at least two layers of the prepreg or substrate according to any of the above (6) to (13), and pressing by heating and pressing.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The composite magnetic substrate of the present invention has a magnetic powder dispersed in a polyvinyl benzyl ether compound.
With such a configuration, a low dielectric constant is obtained,
High frequency range (100MHz or more, especially 100MHz or more 10
GHz range), and it can increase the content of magnetic powder, making it a composite magnetic substrate suitable for applications utilizing magnetic properties or for magnetic shielding, and has high strength. . Further, when a substrate is formed using such a composite magnetic substrate, bonding and patterning with a copper foil can be realized without using a nonmagnetic layer or an adhesive, and multilayering can be realized. Such patterning and multi-layer processing can be performed in the same process as a normal substrate manufacturing process, so that cost reduction and improvement in workability can be achieved. The substrate thus obtained has high strength and improved high frequency characteristics.

Further, the present invention will be described. The polyvinyl benzyl ether compound of the present invention has the following general formula (1)

[0015]

Embedded image

(Wherein, R ¹ represents a methyl group or an ethyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ³ represents a hydrogen atom or a vinylbenzyl group (provided that The molar ratio of hydrogen atom to vinylbenzyl group is 6
0:40 to 0: 100), and n represents a number of 2 to 4).

Further, the present invention provides the following general formula (2)

[0018]

Embedded image

(Wherein, R ¹ represents a methyl group or an ethyl group, R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and n represents a number of 2 to 4). And a vinylbenzyl halide, which is obtained by reacting the compound with a vinylbenzyl halide in the presence of an alkali metal hydroxide and represented by the general formula (1).

In the polyvinyl benzyl ether compound of the present invention represented by the general formula (1), R ¹ represents a methyl group or an ethyl group, and R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, preferably Represents a benzyl group,
R ³ represents a hydrogen atom or a vinylbenzyl group. Here, the molar ratio between the hydrogen atom and the vinylbenzyl group is from 60:40 to 0: 100. Further, n has a value of 2 to 4. The polyvinyl benzyl ether compound of the general formula (1) of the present invention is obtained, for example, by reacting the polyphenol represented by the general formula (2) with vinyl benzyl halide as described in JP-A-9-31006. Can be synthesized.

As the polyphenol of the general formula (2), commercially available ones can be used. For example, PP-700-300 and PP-1000-180 manufactured by Nippon Petrochemical Co., Ltd.
And the like.

Examples of the vinylbenzyl halide include p-vinylbenzyl chloride, m-vinylbenzyl chloride, a mixture of p-vinylbenzyl chloride and m-vinylbenzyl chloride, p-vinylbenzyl bromide, m-vinylbenzyl bromide and p-vinylbenzyl bromide. A mixture of -vinylbenzyl bromide and m-vinylbenzyl bromide. Of these, p-vinylbenzyl chloride and a mixture of p-vinylbenzyl chloride and m-vinylbenzyl chloride are preferred. When p-vinylbenzyl chloride is used, the symmetry is improved, and a polyvinyl benzyl ether compound having a high melting point and a high softening point can be obtained. When a mixture of p-vinylbenzyl chloride and m-vinylbenzyl chloride is used, a polyvinyl benzyl ether compound having a low melting point and a low softening point is obtained, and the workability is improved.

The reaction between polyphenol and vinylbenzyl halide is not particularly limited. For example, polyphenol and vinylbenzyl halide are reacted in a polar neutral solvent using an alkali metal hydroxide as a dehydrochlorinating agent. Method.

The mixing ratio of polyphenol and vinylbenzyl halide can be appropriately designed. For example, the molar ratio of polyphenol: vinylbenzyl halide can be 100: 40 to 100: 120.

As the polar neutral solvent, dimethylformamide, dimethylsulfoxide, dimethylacetamide,
N-methylpyrrolidone, dioxane, acetonitrile,
Examples include tetrahydrofuran, ethylene glycol dimethyl ether, 1,3-dimethoxypropane, 1,2-dimethoxypropane, tetramethylene sulfone, hexamethylphosphamide, methyl ethyl ketone, methyl isobutyl ketone, acetone and mixtures thereof.

Examples of the alkali metal hydroxide include potassium hydroxide, sodium hydroxide and a mixture thereof. The mixing ratio of the alkali metal hydroxide is, for example, preferably about 1.1 to 2.0 times mol per mol of phenolic hydroxyl group.

The reaction temperature and reaction time are each 30
The temperature may be 0.5 to 20 hours at １００100 ° C.

Alternatively, a phase transfer catalyst,
For example, in the presence of a quaternary ammonium salt, the above-mentioned polyphenol and vinylbenzyl halide are mixed in a water / organic solvent mixture by using an alkali metal hydroxide as a dehydrochlorinating agent.
By reacting at a temperature of up to ° C., the polyvinyl benzyl ether compound of the present invention is obtained.

When the polyvinyl benzyl ether compound of the present invention is produced by the above method, the phenolic hydroxyl group in the polyphenol of the general formula (2), one of the starting materials, is All can be made not substituted with vinylbenzyl group. In this case, what is obtained by the above reaction is a mixture of the polyvinyl benzyl ether compound of the present invention and the polyphenol of the general formula (2). In the present invention, the polyphenol may be present as long as it is less than a specific ratio, that is, less than 60 mol% based on both. However, if it exceeds 60 mol%, the curing reaction performed later is not sufficiently achieved, and good dielectric properties are not exhibited.

The substitution ratio of the hydroxyl group of the polyphenol to the vinylbenzyl group in the general formula (2) is 40 to 100 mol%, preferably 60 to 100 mol%. Of course, the higher the substitution rate, the better. This substitution ratio can be appropriately adjusted by a blending design of polyphenol and vinylbenzyl halide.

When the presence of the polyphenol is not allowed, the unreacted raw materials and the like may be removed by a blending design of the polyphenol and vinylbenzyl halide and an appropriate means, for example, a reprecipitation purification method using a combination of a solvent / non-solvent system.

The polyvinyl benzyl ether compound of the present invention is good and constant over a wide frequency range and hardly depends on temperature and hygroscopicity by polymerizing and curing itself or another copolymerizable monomer. It can be used as a resin that shows dielectric properties and has excellent heat resistance.

Examples of the copolymerizable monomer include styrene, vinyl toluene, divinyl benzene, divinyl benzyl ether, allyl phenol, allyl oxybenzene, diallyl phthalate, acrylate, methacrylate, and vinylpyrrolidone. .
The mixing ratio of these monomers is about 2 to 50% by weight based on the polyvinyl benzyl ether compound.

The polyvinyl benzyl ether compound of the present invention may be a known thermosetting resin such as a vinyl ester resin, an unsaturated polyester resin, a maleimide resin, a polycyanate resin of polyphenol, an epoxy resin, a phenol resin, a vinyl benzyl compound, or the like. It is also possible to use in combination with known thermoplastic resins, for example, polyetherimide, polyethersulfone, polyacetal, dicyclopentadiene resin and the like. The compounding ratio is about 5 to 90% by weight based on the polyvinyl benzyl ether compound of the present invention. Among them, preferably,
It is at least one selected from the group consisting of vinyl ester resins, unsaturated polyester resins, maleimide resins, polyphenol polycyanate resins, epoxide resins, and mixtures thereof.

The polymerization and curing of the polyvinyl benzyl ether compound of the present invention itself or a curable resin composition containing the compound and another monomer or a thermosetting resin can be carried out by a known method. it can. Curing is possible either in the presence or absence of a curing agent. When a curing agent is used, for example, benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, t
A known radical polymerization initiator such as -butyl perbenzoate can be used. The amount used is 0 to 10 parts by weight based on 100 parts by weight of the polyvinyl benzyl ether compound.

The curing temperature varies depending on whether or not a curing agent is used and the type of the curing agent and cannot be unconditionally specified, but it is 20 to 250 ° C., preferably 50 to 250 ° C. If the temperature is lower than 20 ° C., sufficient curing cannot be obtained.

For adjusting the curing, hydroquinone, benzoquinone, copper salt and the like can be blended.

The magnetic powder used in the present invention is not particularly limited, but specific examples include ferrite and ferromagnetic metal powder.

As ferrite, Mn-Mg-Zn
System, Ni-Zn system, Mn-Zn system, etc., and Mn-M
A g-Zn system, a Ni-Zn system, and the like are preferable.

As ferromagnetic metals, carbonyl iron, iron-
Silicon-based alloys, iron-aluminum-silicon-based alloys (trade name: Sendust), iron-nickel-based alloys (trade name: Permalloy), amorphous (iron-based, cobalt-based) and the like are preferable.

Means for making these into powder are pulverization,
A known method such as granulation may be used.

The particle size of the magnetic powder is preferably from 0.01 to 100 μm, and the average particle size is preferably from 1 to 50 μm. With such a particle size, the dispersibility of the magnetic powder is improved, and the effect of the present invention is improved. On the other hand, when the particle size of the magnetic powder is large, the magnetic powder tends to settle when it is made into a paste, and is difficult to be uniformly dispersed. Also, when it is attempted to form a thin substrate or prepreg, it becomes difficult to obtain a smooth surface. It is practically difficult to make the particle size too small, and the limit is about 0.01 μm.

The particle size of the magnetic powder is preferably uniform, and if necessary, the particle size may be uniformed by sieving or the like. The shape of the magnetic component may be any one of a spherical shape, a flat shape, and an elliptical shape, and may be properly used depending on the application. If necessary, the surface may be subjected to a treatment such as oxidation, coupling, or coating of an organic insulating material.

Further, two or more kinds of magnetic powders having different types and particle size distributions may be used. The mixing ratio at that time is arbitrary,
The material used, the particle size distribution, and the mixing ratio may be adjusted depending on the application.

The magnetic permeability μ of the magnetic powder is 10 to 1,000,000
It is preferred that In addition, it is preferable that the bulk insulating property is high because the insulating property when the substrate is formed is improved.

The mixing ratio between the polyvinyl benzyl ether compound and the magnetic powder of the present invention preferably satisfies the following relationship when expressed by the ratio of the resin to the magnetic powder in the paste step of coating on a glass cloth or the like. .

Polyvinyl benzyl ether compound: magnetic powder = 100: 100-100: 900 That is, the content of the magnetic powder is preferably 50-90 wt%. By setting the content of such magnetic powder,
The effect of the present invention is improved. On the other hand, when the content of the magnetic powder is large, it is difficult to form a slurry and apply the slurry, and it is difficult to prepare a substrate and a prepreg. On the other hand, when the content of the magnetic powder is small, the magnetic permeability may not be able to be secured, and the magnetic properties may be reduced.

The glass cloth used in the present invention may be of various types depending on the purpose and application, and a commercially available glass cloth can be used as it is. Its thickness is less than 100μm,
Particularly, the thickness is preferably 20 to 60 μm. The cloth weight is preferably 120 g / m ² or less, particularly preferably ²⁰ to 70 g / m ² .

Further, a surface treatment such as a coupling treatment may be performed for the purpose of increasing interlayer adhesion or preventing deterioration of characteristics. Also, depending on the electrical characteristics, E
Glass cloth (ε = 7, tanδ = 0.003, 1GH
z), D glass cloth (ε = 4, tan δ = 0.0013,
1 GHz), H glass cloth (ε = 11, tan δ = 0.
003, 1 GHz) or the like.

The metal foil to be used may be any suitable metal having good conductivity, such as gold, silver, copper and aluminum. Of these, copper is particularly preferred.

As a method for producing a metal foil, various known methods such as an electrolytic method and a rolling method can be used. However, when a foil peel strength is desired, an electrolytic foil is used. It is preferable to use a rolled foil which is less affected by the skin effect due to surface irregularities.

The thickness of the metal foil is preferably from 8 to 70 μm, particularly preferably from 12 to 35 μm.

In order to obtain a prepreg in the present invention, a paste containing a magnetic powder having a predetermined mixing ratio and a polyvinyl benzyl ether compound, and kneaded in a solvent to form a slurry is applied and dried (B-stage). Follow the process.
The solvent used in this case is preferably a volatile solvent, and is used for the purpose of adjusting the viscosity of the paste to facilitate coating. The kneading may be performed by a known method using a ball mill, stirring, or the like. It can be formed by coating a paste on a metal foil or impregnating a glass cloth.

The drying (B-stage) of the prepreg may be appropriately adjusted depending on the content of the magnetic powder to be contained, but it is usually 100 to 180 ° C. and 0.1 to 3 hours. The thickness after drying and B-stage is 50-300
The thickness is preferably on the order of μm, and the film thickness may be adjusted to an optimum value according to the application and required characteristics (pattern width and accuracy, DC resistance) and the like.

The prepreg of the present invention can be manufactured by a method as shown in FIG. 1 or FIG. In this case, the method of FIG. 1 is relatively suitable for mass production, and the method of FIG. 2 is characterized in that the film thickness can be easily controlled and the characteristics can be adjusted relatively easily. In FIG. 1, a glass cloth 101 wound in a roll shape as shown in FIG.
a is unwound from the roll 101a and is conveyed to the coating tank 110 via the guide roller 111. In this coating tank 110, a magnetic powder and a polyvinyl benzyl ether compound dispersed in a solvent are prepared in a slurry state, and when a glass cloth passes through this coating tank 110, it is immersed in the slurry, The cloth is coated and the gaps in it are filled.

The glass cloth that has passed through the coating tank 110 is
Drying furnace 12 through guide rollers 112a and 112b
0 is introduced. The resin-impregnated glass cloth introduced into the drying furnace is dried at a predetermined temperature and for a predetermined time, B-staged, turned around by the guide roller 121, and wound around the winding roller 130.

Then, when cut into a predetermined size,
As shown in (b), a prepreg in which the resin containing the magnetic powder is disposed on both surfaces of the glass cloth 101 is obtained.

Further, as shown in (c), a metal foil 103 such as a copper foil is placed on the upper and lower surfaces of the obtained prepreg, and is pressed under heat and pressure to obtain a double-sided film as shown in (d). A substrate with a metal foil is obtained. Heating and pressing conditions are 10
Temperature of 0 to 200 ° C, 9.8 × 10 ^{5 to} 7.84 × 10 ⁶
The pressure may be Pa (10 to 80 kgf / cm ² ), and it is preferable to mold under such conditions for about 0.5 to 20 hours. The molding can be performed in a plurality of stages under different conditions. In the case where no metal foil is provided, heating and pressing may be performed without disposing the metal foil.

Next, the manufacturing method of FIG. 2 will be described.
In FIG. 2, as shown in FIG. 2 (a), a slurry 102a in which a magnetic powder and a polyvinyl benzyl ether compound are dispersed in a solvent is coated on a metal foil such as a copper foil while keeping a constant clearance by a doctor blade 150 or the like. .

Then, when cut into a predetermined size,
As shown in (b), a prepreg in which a resin containing magnetic powder is disposed on the upper surface of the metal foil 103 is obtained.

Further, as shown in (c), the prepregs 102 and 10 obtained on the upper and lower surfaces of the glass cloth 101 were obtained.
3 are arranged with the resin 102 side as the inner surface, and are pressed under heat and pressure to obtain a substrate with double-sided metal foil as shown in (d). The heating and pressing conditions may be the same as described above.

The substrate and prepreg of the present invention can also be obtained by kneading materials and molding a kneaded material in a solid state, in addition to the above-mentioned coating method. In this case, since the raw material is solid, it is easy to take a thickness, and is suitable as a method for forming a relatively thick substrate or prepreg.

The kneading needs to be at least the melting point of the polyvinyl benzyl ether compound. The melting point of the polyvinyl benzyl ether compound is usually 50 to 150.
It is about ° C. The kneading may be performed by a known method such as a ball mill, stirring, and a kneader. At that time, a solvent may be used if necessary. Further, it may be pelletized or powdered as necessary.

The obtained kneaded material, such as pelletized or powdered, is molded by heating and pressure using a mold. As molding conditions, 100-200 ° C., 0.5-3 hours, 4.9 × 1
The pressure may be in the range of 0 ^{5 to} 7.84 × 10 ⁶ Pa ( ^{5 to} 80 kgf / cm ² ).

The thickness of the prepreg obtained in this case is about 0.05 to 5 mm. The thickness of the prepreg may be appropriately adjusted according to the desired plate thickness and magnetic powder content.

Further, a metal foil such as a copper foil was placed on both the upper and lower surfaces of the prepreg obtained in the same manner as described above, and this was heated and heated.
When pressed under pressure, a substrate with double-sided metal foil is obtained. The heating and pressurizing condition is a temperature of 100 to 200 ° C., and 9.8 × 10 ⁵ to
The pressure may be 7.84 × 10 ⁶ Pa (10 to 80 kgf / cm ² ), and it is preferable to mold under such conditions for about 0.5 to 20 hours. The molding can be performed in a plurality of stages under different conditions. In the case where no metal foil is provided, heating and pressing may be performed without disposing the metal foil.

The substrate (organic composite material) as a molding material thus obtained is excellent in high frequency characteristics of magnetic permeability and dielectric constant. In addition, it has excellent insulating properties that can be endured as an insulating material. Furthermore, when a substrate with a copper foil is used as described later, the adhesive strength with the copper foil is large. Also, it has excellent heat resistance such as solder heat resistance.

The prepreg of the present invention can form a substrate with a copper foil by forming the prepreg on a copper foil by applying heat and pressure. In this case, the thickness of the copper foil is about 12 to 35 μm. Examples of such a substrate with a copper foil include a double-sided patterned substrate and a multilayer substrate.

FIGS. 3 and 4 show process diagrams of an example of forming a double-sided patterned substrate. As shown in FIG. 3 and FIG. 4, a prepreg 1 having a predetermined thickness and a copper (Cu) foil 2 having a predetermined thickness are stacked, pressed and heated to form (step A). Next, through holes are formed by drilling (step B). Copper (Cu) plating is applied to the formed through holes to form a plating film 4 (step C). Further, the copper foils 2 on both sides are patterned to form conductor patterns 21 (step D). Thereafter, as shown in FIG. 3, plating for connecting external terminals and the like is performed (step E). In this case, plating is performed by a method of further plating Pd after Ni plating, a method of further plating Au after Ni plating (plating is electrolytic or electroless plating), or a method using a solder leveler.

FIGS. 5 and 6 are process diagrams of an example of forming a multilayer substrate, and show an example in which four layers are stacked. As shown in FIG. 5 and FIG. 6, a prepreg 1 having a predetermined thickness and a copper (Cu) foil 2 having a predetermined thickness are stacked, pressed and heated to form (step a). Next, the copper foils 2 on both sides are patterned to form conductor patterns 21 (step b). A prepreg 1 and a copper foil 2 each having a predetermined thickness are further laminated on both surfaces of the double-sided patterned substrate thus obtained, and are simultaneously molded by applying pressure and heat (step c). Next, through holes are formed by drilling (step d). The formed through holes are plated with copper (Cu) to form a plating film 4 (step e). Further, the copper foils 2 on both sides are patterned to form conductor patterns 21 (step f). Thereafter, as shown in FIG. 5, plating for connection to external terminals is performed (step g). In this case, plating is performed by a method of further plating Pd after Ni plating, a method of further plating Au after Ni plating (plating is electrolytic or electroless plating), or a method using a solder leveler.

The molding conditions for the above heating and pressurization are 100 to 2
At a temperature of 00 ° C., 9.8 × 10 ^{5 to} 7.84 × 10 ⁶ Pa (1
Preferably, the pressure is 0 to 80 kgf / cm ² ) for 0.5 to 20 hours.

In the present invention, not limited to the above example, various substrates can be formed. For example, it is also possible to use a substrate as a molding material or a substrate with a copper foil and a prepreg, and use the prepreg as an adhesive layer to form a multilayer.

In a mode in which a copper foil is bonded to a substrate as a prepreg or a molding material, a magnetic powder obtained by kneading the above-mentioned magnetic powder, a polyvinyl benzyl ether compound and a high boiling solvent such as butyl carbitol acetate is kneaded. The material paste may be formed on the patterned substrate by screen printing or the like, whereby the characteristics can be improved. It is preferable that the magnetic powder content in such a magnetic material paste is 50 to 90% by weight, the polyvinyl benzyl ether compound is 3 to 50% by weight, and the solvent is the balance.
The thickness of the coating film is 30 to 150 μm on the molded substrate.
m is preferred.

[0074]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention. <Example 1> [Ferrite-based composite magnetic material] Using Mn-Mg-Zn-based ferrite (μ320) as a ferrite powder as a magnetic powder and an average particle size of 3 μm, this and a polyvinylbenzyl ether compound were dissolved in toluene, A slurry was made. The kneading was agitated in a ball mill. At this time, a sample was prepared by mixing the ferrite powder with the polyvinyl benzyl ether compound at 65 wt% and 80 wt%.

The obtained slurry was coated on a 35 μm-thick electrolytic copper foil using a doctor blade,
After drying for a time, a prepreg was obtained. The film thickness of the composite magnetic material after drying was 150 μm.

A glass cloth (product number: 106, Arisawa Seisakusho) having a thickness of 38 μm and a cloth weight of 24.8 g / m ² was prepared, and the prepreg was arranged on both upper and lower surfaces of the glass cloth so that the metal surfaces were outside. Then, press molding was performed under the following conditions to obtain a substrate with double-sided metal foil. 120 ° C / 30 minutes → 150 ° C / 30 minutes → 180 ° C / 30
Min → 200 ° C./30 min Press pressure: 3.43 × 10 ⁶ Pa (35 kgf / cm ² )

The thickness of the obtained substrate with a double-sided metal foil is 0.3 mm.
It was 30 mm.

The dielectric constant of each of the obtained samples (1 MHz, 1
(00 MHz), dielectric loss tangent (100 MHz), volume resistivity, and magnetic permeability. The results are shown in FIGS.

Comparative Example 1 In Example 1, a phenol novolak type epoxy resin was used in place of the polyvinyl benzyl ether compound, and methyl ethyl ketone (MEK) was used as a solvent. At this time, the mixing ratio of the phenol novolak type epoxy resin to the ferrite powder was 6%.
A sample in which 5 wt% and 80 wt% were mixed was prepared. Otherwise, the slurry was prepared in the same manner as in Example 1.

The obtained slurry was coated on a 35 μm-thick electrolytic copper foil using a doctor blade,
It dried in 0 minute and obtained the prepreg. The film thickness of the composite magnetic material after drying was 150 μm.

A glass cloth (product number: 106, Arisawa Seisakusho) having a thickness of 38 μm and a cloth weight of 24.8 g / m ² was prepared, and the prepreg was arranged on both upper and lower surfaces of the glass cloth such that the metal surfaces were outside. Then, press molding was performed under the following conditions to obtain a substrate with double-sided metal foil. 110 ° C./30 minutes + 180 ° C./60 minutes Press pressure: 3.92 × 10 ⁶ Pa (40 kgf / cm ² )

The thickness of the obtained substrate with a double-sided metal foil was 0.1 mm.
It was 30 mm.

The dielectric constant of each sample (1 MHz, 1
(00 MHz), dielectric loss tangent (100 MHz), volume resistivity, and magnetic permeability. The results are shown in FIGS.

As is clear from FIGS. 7 to 11, the samples of the present invention have a dielectric constant reduced by 20 to 25% and a dielectric loss tangent is also reduced. This is considered to be due to the dielectric constant and dielectric loss tangent of the base polyvinyl benzyl ether compound. In addition, it can be seen that the volume resistivity can secure a value equal to or higher than that of the epoxy resin. The magnetic permeability is slightly different because the indicated value is wt%, but it is almost the same value when converted into the volume content. As for the frequency characteristics, the real component of magnetic permeability remains up to the GHz band, which is an advantage of the composite magnetic material, and the imaginary component of magnetic permeability has a peak near 1 GHz, and it can be expected to be used in a high-frequency region not found in bulk ferrite.

<Example 2> [Ferromagnetic metal-based composite magnetic material] In Example 1, an Fe-Si-Cr flat powder having a length of 50 µm and a thickness of 0.2 to 0.3 µm was used as a magnetic material. In the same manner as in Example 1, a slurry paste was obtained. At that time, the mixing ratio of the metal powder was 50 wt.
%, 70% by weight.

The obtained slurry was applied on an electrolytic copper foil having a thickness of 35 μm using a doctor blade.
After drying for a time, a prepreg was obtained. The film thickness of the composite magnetic material after drying was 150 μm.

A glass cloth (product number: 106, Arisawa Seisakusho) having a thickness of 38 μm and a cloth weight of 24.8 g / m ² was prepared, and the prepreg was arranged on both upper and lower surfaces of the glass cloth so that the metal surfaces were outside. Then, press molding was performed under the following conditions to obtain a substrate with double-sided metal foil. 120 ° C / 30 minutes → 150 ° C / 30 minutes → 180 ° C / 30
Min → 200 ° C./30 min Press pressure: 3.43 × 10 ⁶ Pa (35 kgf / cm ² )

The thickness of the obtained substrate with a double-sided metal foil was 0.1 mm.
It was 30 mm.

The magnetic permeability and dielectric constant (1
00 MHz) and the frequency characteristics of the magnetic permeability. The results are shown in FIGS. 12, 13, and 14.

Comparative Example 2 Ferromagnetic Metal Composite Magnetic Material In Example 2, a phenol novolak type epoxy resin was used in place of the polyvinyl benzyl ether compound.
Methyl ethyl ketone (MEK) was used as a solvent. The mixing ratio at this time was prepared by mixing 50 wt% and 70 wt% of the metal powder with the phenol novolak type epoxy resin. Otherwise, the slurry was prepared in the same manner as in Example 2.

The obtained slurry was coated on a 35 μm-thick electrolytic copper foil using a doctor blade,
It dried in 0 minute and obtained the prepreg. The film thickness of the composite magnetic material after drying was 150 μm.

A glass cloth (product number: 106, Arisawa Seisakusho) having a thickness of 38 μm and a cloth weight of 24.8 g / m ² was prepared, and the prepreg was arranged on both upper and lower surfaces of the glass cloth such that the metal surfaces were outside. Then, press molding was performed under the following conditions to obtain a substrate with double-sided metal foil. 110 ° C./30 minutes + 180 ° C./60 minutes Press pressure: 3.92 × 10 ⁶ Pa (40 kgf / cm ² )

The thickness of the obtained substrate with a double-sided metal foil was 0.1 mm.
It was 30 mm.

The magnetic permeability and dielectric constant (1
00 MHz) and the frequency characteristics of the magnetic permeability. The results are shown in FIGS. 12, 13, and 14.

As is apparent from the figure, the dielectric constant is 30 to 4 compared to the sample of Example 1 using ferrite powder.
It can be seen that it has decreased by 5%. This is considered to be due to the fact that the dielectric constant of the metal powder is higher than that of ferrite and that the dielectric constant becomes closer to a series connection because of the flat shape. In other words, in a composite material formed using the doctor blade method or the like, the metal powder is oriented, and in the direction in which the metal powder is oriented, the ratio of the base resin increases, and the dielectric constant becomes more dominant. It is thought to be. Therefore, at the same content, the dielectric constant is lower than when ferrite powder is used.

<Example 3> [Ferrite-based composite magnetic material] Mn-Mg-Zn-based ferrite (µ320) as a ferrite powder and an average particle diameter of 3 µm were used as the magnetic powder, and this was mixed with a polyvinyl benzyl ether compound in toluene. Dissolved to form a slurry. This slurry is heated at 90 ° C, 15
The mixture was dried over time and pulverized by a pulverizer to obtain a kneaded material of a magnetic material and a vinylbenzyl resin (powder). At this time, a sample was prepared by mixing the ferrite powder with the polyvinyl benzyl ether compound at 65 wt% and 80 wt%.

A predetermined amount of this raw material powder is put into a mold,
A prepreg was obtained by press molding at 0 ° C. for 30 minutes at 2.94 × 10 ⁶ Pa (30 kgf / cm ² ). The thickness of the obtained prepreg was 1 mm.

On both sides of the obtained prepreg, a thickness of 18 μm
Of copper foil, sandwich the prepreg with a lever,
30 minutes → 150 ° C / 30 minutes → 180 ° C / 30 minutes → 200
° C / 30 min step cure (3.43 × 10 ⁶ Pa (3
Press molding was performed at 5 kgf / cm ² )). The thickness of the obtained substrate with double-sided metal foil was 1.02 mm.

The dielectric constant (1 MHz) of each of the obtained samples was measured. FIG. 15 shows the results.

Comparative Example 3 In Example 3, a phenol novolak type epoxy resin was used in place of the polyvinyl benzyl ether compound, and methyl ethyl ketone (MEK) was used as a solvent. At this time, the mixing ratio of the phenol novolak type epoxy resin to the ferrite powder was 6%.
A sample in which 5 wt% and 80 wt% were mixed was prepared. Otherwise, the raw material powder was prepared in the same manner as in Example 3.

A predetermined amount of this raw material powder is put into a mold, and
A prepreg was obtained by press molding at 0 ° C. for 30 minutes at 2.94 × 10 ⁶ Pa (30 kgf / cm ² ). The thickness of the obtained prepreg was 1 mm.

On both sides of the obtained prepreg, a thickness of 18 μm
Of copper foil, sandwich the prepreg with a lever,
30 minutes → 150 ° C / 30 minutes → 180 ° C / 30 minutes → 200
° C / 30 min step cure (3.43 × 10 ⁶ Pa (3
Press molding was performed at 5 kgf / cm ² )). The thickness of the obtained substrate with double-sided metal foil was 1.02 mm.

The dielectric constant (1 MHz) of each of the obtained samples was measured. FIG. 15 shows the results.

As apparent from the figure, the dielectric constant is reduced by 20 to 25% as compared with the epoxy-based comparative sample. This is considered to be due to the influence of the dielectric constant of the base resin. When the magnetic characteristics were measured in Example 3 and Comparative Example 3 in the same manner as in Example 1, almost the same results as in Example 1 and Comparative Example 1 were obtained.

<Example 4> [Evaluation of characteristics of coil using ferrite-based composite magnetic material] Using the samples (substrates with double-sided metal foil) prepared in Example 1 and Comparative Example 1, the shape as shown in FIG. 16 was used. And 3.2 ×
A coil array (four units) having a size of 1.6 mm was prepared.
16A is a plan view, FIG. 16B is a rear view, and FIG. 16C is a plan view showing a state where a resin is applied. In FIG. 16, a printed pattern 92 is formed on a substrate main body 91, and a base resin 93 is further applied.

The method of preparation was as follows. After preparing a double-sided patterned substrate, the base resin was used in Example 1 and Comparative Example 1.
The composite magnetic material paste containing 65 wt% of the ferrite powder was screen-printed and thermally cured to form a coil. The thickness of the obtained coil was 70 μm, and the product height was 0.44 mm. FIG. 17 shows the obtained results of measuring the frequency characteristics of the coil.

As apparent from FIG. 17, the impedance (upper curve in the figure: solid line) and the reactance (lower curve in the figure: dashed line) frequency characteristic peaks were approximately 400 MHz on the high frequency side in the sample method using vinylbenzyl. It can be seen that it extends. This is because the dielectric constant of the substrate material is low and the stray capacitance of the coil is small.In making coils that take advantage of the magnetic characteristics, the dielectric characteristics that make the most of the high-frequency characteristics, which is the advantage of composite materials, can be obtained. You can see that it is.

[0108]

As described above, according to the present invention, it is possible to provide (1) a composite magnetic substrate and a prepreg having a low dielectric constant and a low dielectric loss tangent, and (2) a high heat resistance having a high glass transition point and a decomposition starting point temperature. Composite magnetic substrate and prepreg can be provided,
(3) It is possible to provide a composite magnetic substrate and a prepreg having a low water absorption rate and a small change in dielectric constant and dielectric loss tangent. It is possible to provide a composite magnetic substrate and a prepreg that can be manufactured. (5) It is possible to provide a composite magnetic substrate and a prepreg whose dielectric constant is constant up to a frequency band of GHz.
(6) It is possible to provide a composite magnetic substrate and a prepreg having a small temperature dependence of a dielectric constant.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of forming a substrate with a copper foil of the present invention.

FIG. 2 is another process drawing showing an example of forming a substrate with a copper foil of the present invention.

FIG. 3 is a process chart showing an example of forming a substrate with a copper foil according to the present invention.

FIG. 4 is another process drawing showing an example of forming a substrate with a copper foil of the present invention.

FIG. 5 is a process chart showing an example of forming a multilayer substrate of the present invention.

FIG. 6 is a process chart showing an example of forming a multilayer substrate of the present invention.

FIG. 7 shows a dielectric constant (1 MHz) of a substrate (a ferrite powder-containing molding material) according to the present invention and a comparative example depending on a ferrite powder content.
FIG.

FIG. 8 shows a dielectric constant (100M) of a substrate (a ferrite powder-containing molding material) according to the present invention and a comparative example based on a ferrite powder content.
Hz).

FIG. 9 shows a dielectric loss tangent (100) based on the ferrite powder content of the substrate (molding material containing ferrite powder) of the present invention and a comparative example.
(MHz).

FIG. 10 is a graph showing the volume resistivity according to the content of ferrite powder in the substrates (molding material containing ferrite powder) of the present invention and a comparative example.

FIG. 11 is a graph showing frequency characteristics of magnetic permeability depending on the content of ferrite powder in substrates (ferrite powder-containing molding material) of the present invention and a comparative example.

FIG. 12 is a graph showing the magnetic permeability according to the metal powder content of the substrate (metal powder-containing molding material) of the present invention and a comparative example.

FIG. 13 is a graph showing the dielectric constant depending on the metal powder content of the substrate (metal powder-containing molding material) of the present invention and a comparative example.

FIG. 14 is a graph showing the frequency characteristics of the magnetic permeability according to the content of the metal powder of the substrate (metal powder-containing molding material) of the present invention and a comparative example.

FIG. 15 is a graph showing the dielectric constants of substrates of the present invention and a comparative example (with double-sided metal foil).

FIG. 16 is a schematic view showing a conductor pattern on the front side of the substrate element (coil) of the present invention, wherein (a) is a conductor pattern on the front side;
(B) shows a state where a conductor pattern on the back side is provided, and (c) shows a state where a paste pattern is provided.

FIG. 17 is a graph showing frequency characteristics of impedance and reactance of a substrate element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Prepreg 2 Cu foil 3 Through hole 4 Cu plating film 21 Conductor pattern

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08F 12/22 C08F 12/22 299/00 299/00 C08J 5/10 CEZ C08J 5/10 CEZ 5/24 5/24 F-term (reference) 4F072 AA04 AA07 AB09 AB28 AD11 AD53 AE08 AF02 AG03 AG17 AH04 AH32 AJ04 AK02 AK03 AK05 AK14 AL13 4H006 AA03 AB78 GP03 GP12 4J027 AB01 AE01 AH03 AJ02 AJ08 BA01 BA04 BA05 BA07 BA02 BA07 BA02 BA07 AB16Q AE63Q AG71Q AL02Q AQ08Q BA02P BA02Q BA03Q BC12P BC43P CA01 CA04 JA43 5E346 AA06 AA12 AA15 AA22 AA26 CC04 CC08 EE02 EE06 EE09 GG28 HH01 HH11 HH18

Claims (14)

[Claims] 1. A composite magnetic substrate in which a magnetic powder is dispersed in a polyvinyl benzyl ether compound. 2. The composite magnetic substrate according to claim 1, wherein the polyvinyl benzyl ether compound is represented by the following general formula (1). Embedded image (Wherein, R ¹ represents a methyl group or an ethyl group; R ² represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms;
³ represents a hydrogen atom or a vinylbenzyl group (provided that the molar ratio of the hydrogen atom to the vinylbenzyl group is from 60:40 to
0: 100), and n represents a number of 2 to 4). 3. The composite magnetic substrate according to claim 1, wherein said magnetic powder is a ferromagnetic metal or ferrite. 4. The particle size of the magnetic powder is 0.01 to 100.
The composite magnetic substrate according to any one of claims 1 to 3, which has a thickness of µm. 5. The composite magnetic substrate according to claim 1, wherein the content of said magnetic powder is 50 to 90 wt%. 6. A prepreg obtained by applying a slurry in which a polyvinyl benzyl ether compound and a magnetic powder are dispersed in a solvent to a glass cloth and drying the slurry. 7. A prepreg obtained by applying a slurry in which a polyvinyl benzyl ether compound and a magnetic powder are dispersed in a solvent to a metal foil and drying the slurry. 8. A substrate obtained by heating and press-pressing the prepreg according to claim 6. 9. A substrate with a double-sided metal foil obtained by arranging metal foils on both sides of the prepreg according to claim 6 and heating and pressing the metal foils. 10. The prepreg according to claim 7, which is disposed on both sides of the glass cloth with the metal foil side facing outward, and
Substrate with double-sided metal foil obtained by pressing. 11. A prepreg obtained by kneading a polyvinyl benzyl ether compound and magnetic powder at least at a temperature not lower than the melting point of the polyvinyl benzyl ether compound, and press-molding the solid kneaded product. 12. A substrate obtained by heating and press-pressing the prepreg according to claim 11. 13. A substrate with a double-sided metal foil obtained by disposing a metal foil on both sides of the prepreg according to claim 11 and pressing the metal foil with heat and pressure. 14. A multilayer substrate obtained by laminating two or more layers of the prepreg or substrate according to at least one of claims 6 to 13 and pressing under heat and pressure.