JP2802172B2 - Composite dielectric and printed circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite dielectric and a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, resin has been used as a dielectric, for example, a dielectric for a capacitor which is one of electronic circuit elements. Among them, polyphenylene oxide (hereinafter, referred to as PP) as a resin having a small dielectric loss (tan δ) in a high frequency range.
O (abbreviated as O) is attracting attention as being suitable for recent demands for higher frequencies.

However, in order to reduce the size of electronic circuit elements, it is desired to further increase the dielectric constant. In this regard, PPO, which has a small dielectric loss in a high frequency range, does not have a very high dielectric constant. From the standpoint of improving the dielectric constant, attention has been paid to composite techniques for increasing the dielectric constant by dispersing inorganic dielectric particles in a resin, and many applications have been filed (for example, Japanese Patent Publication Nos. 49-25159 and 54-59). 18754). The composite dielectric obtained by this composite maintains the advantages of the resin, such as easy area enlargement and good post-processing (cutting, opening, bonding, etc.).

[0004]

However, this composite dielectric containing inorganic dielectric particles has a problem that the dielectric constant is not improved enough to match the amount of inorganic dielectric particles added. There is a limit to increasing the amount of inorganic dielectric particles to be added, and it is not easy to develop a new compound for inorganic dielectric particles.

In the inventions described in JP-B-49-25159 and JP-B-54-18754, the effect of the particle size of dispersed particles is studied. However, the research results of the inventors have found that simply increasing the particle size is less effective in ensuring a high dielectric constant with the same filling amount. Therefore, solving this point is one problem.In addition, sedimentation and separation are likely to occur when the particle diameter of the inorganic dielectric particles is large. Another problem that needs to be solved in this composite dielectric containing body particles.

Further, depending on the application, it is necessary to improve physical properties such as heat resistance, chemical resistance, and physical strength (rigidity). When used at a high frequency, dimensional accuracy is important, but conventional PPO has poor dimensional stability, that is, a large thermal expansion coefficient, and its improvement has been desired. Crosslinking of a resin is performed as one of the methods to meet such a demand. However, PPO cannot be cross-linked (cured) by a simple treatment such as ordinary thermosetting resin. For these reasons, conventionally, a PPO-based composite dielectric having excellent high-frequency characteristics and heat resistance and excellent dimensional stability cannot be obtained easily. Therefore, a solution to this point is a third problem.

On the other hand, in the advanced information age, information transmission tends to be faster and higher frequency. Mobile radio such as car phone and personal radio, satellite broadcasting, satellite communication and CAT
In the new media such as V, downsizing of devices is being promoted, and accordingly, miniaturization of microwave circuit elements such as dielectric resonators is strongly desired. The size of the microwave circuit element is based on the wavelength of the electromagnetic wave used. The wavelength λ of an electromagnetic wave propagating in a dielectric material having a relative permittivity εr is given by λ = λa /
(Εr) is ^0.5 . Therefore, the device becomes smaller as the permittivity of the printed circuit board used increases. In addition, when the dielectric constant of the substrate is large, electromagnetic energy is concentrated in the substrate, so that leakage of electromagnetic waves is small, which is convenient. In this type of printed circuit board, as long as the above-mentioned composite dielectric is used as the dielectric material, in addition to the problem of the improvement of the dielectric constant, the problem of the sedimentation of the particles, the problem of the improvement of the physical properties such as heat resistance, and the dimensional stability. There is still a problem of improving the sex.

In view of such circumstances, the present invention provides a composite dielectric having a high dielectric constant, excellent physical properties such as heat resistance, chemical resistance, and physical strength (rigidity), and excellent dimensional stability. It is an object to provide a printed circuit board.

[0009]

Means for Solving the Problems In order to solve the above problems, in the composite dielectric according to the present invention, a porous inorganic dielectric particle is made of a PPO-based composition containing PPO and a crosslinkable polymer and / or a crosslinkable monomer. Is dispersed in a resin consisting of In order to solve the above problems, in the printed circuit board according to the present invention, the porous inorganic dielectric particles are dispersed in a resin composed of a PPO-based composition containing PPO and a crosslinkable polymer and / or a crosslinkable monomer. The composite dielectric is used as a dielectric material.

[0010] The porous inorganic dielectric particles used in the present invention are particles having a large number of voids, such as holes and cracks, which open toward the surface, and are such that a resin can enter the voids. It is in a state. The state is as shown in FIG. 1, for example. In the figure, a spherical shape represents porous inorganic dielectric particles, and a black background portion represents a resin. Porous inorganic dielectric particles are dispersed in the resin,
Part of the resin has entered the voids of the particles.

The porous inorganic dielectric particles have an average particle size of 5 to 100 μm and an average specific surface area of 0.3 to 7.0 m ² / g.
r is preferred. When the particle size exceeds 100 μm, irregularities due to particles appear on the surface of the composite dielectric, resulting in poor smoothness, poor moisture resistance (water resistance), poor induced loss characteristics, and the like. There is a tendency that the particles are easily broken at the time of production or the like, and the dielectric properties vary. When the particle size is less than 5 μm, the effect of improving the dielectric constant tends to be insufficient.

When the specific surface area exceeds 7.0 m ² / gr,
There is a tendency that moisture resistance (water resistance) becomes inferior and dielectric loss characteristics deteriorate. When the specific surface area is less than 0.3 m ² / gr, the effect of improving the dielectric constant tends to be insufficient. The porous inorganic dielectric particles may be secondary particles formed by aggregation of primary particles. The secondary particles are porous due to voids between the primary particles. in this case,
The primary particles constituting the porous particles are preferably physically and chemically bonded to each other by sintering.

The porous inorganic dielectric particles are preferably made of a compound having a high dielectric constant composition having a perovskite crystal structure. Examples of the porous inorganic dielectric particles include BaTiO ₃ , SrTiO ₃ , and PbTi _1/2 Z
r _1/2 O ₃ system, Pb (Mg _2/3 Nb _1/3 ) O ₃ system, Ba
(Sn _X Mg _Y Ta _Z ) O ₃ , Ba (Zr _X Zn _Y T
a _Z ) O ₃ -based compounds having a perovskite-type crystal structure (or a composite perovskite-type crystal structure), and other inorganic compounds such as TiO ₂ , ZrO ₂ , and SnO ₂ alone and their composite oxides. No. The porous inorganic dielectric particles may have a spherical shape or a block-like shape of various shapes, and the shape is not particularly limited.

The porous inorganic dielectric particles include, for example,
The inorganic dielectric block obtained by making the sintered density low and porous may be crushed, or the inorganic powder may be ground with a binder (for example, PVA = polyvinyl alcohol aqueous solution).
It can be obtained by, for example, dispersing and spraying in a dry atmosphere (for example, a temperature atmosphere of about 130 ° C.) to obtain a granular material, and firing it at a temperature of about 1100 ° C. In the latter case, various inorganic powders can be selected, but in the case of sintering, in the granules obtained by spraying, the powders in the individual granules are physically and chemically bonded by sintering. In particular, when the starting material is fine particles, grain growth occurs, but the grains are separated to such an extent that they are easily separated. Sintered particles have pores and cracks that open on the surface and have voids inside,
It is porous.

In the sintering, a sintering aid may be used if necessary. As the sintering aid, any auxiliaries usually used when sintering such powders may be used, but if defined strictly, they do not destroy the dielectric composition, It is preferable to use a material which does not impair the characteristics and gives a sufficient reinforcing effect. The amount of the sintering aid used may be appropriately selected depending on the purpose and the type of the sintering aid, but is usually 0.1 to 5% by weight based on the inorganic dielectric particles. preferable. Any particle diameter of the sintering aid can be used as long as it is in the range of 0.01 to 100 μm, but it is preferably about 0.1 to 50 μm for uniform dispersion. The sintering aid may be added at any time during the preparation and firing steps of the inorganic dielectric compound. For example, when the inorganic powder is dispersed in the binder, the sintering aid is dispersed at the same time.

The use of a sintering aid not only has the effect of facilitating sintering as compared to the case where it is not used, but also improves the strength of the porous particles. In addition, the collapsible effect of preventing the collapse of the porous dielectric particles and the sintering at a relatively low temperature make it possible to form porous particles having a higher porosity and reduce the dielectric constant of the composite dielectric. Ancillary effects such as improvement may be exhibited.

The following are specific examples of the sintering aid.
You. That is, BaO-SiO_Two-B_TwoO_Three, CaO
-SiO_Two-B_TwoO_Three, Li_TwoO-SiO_Two-B
_TwoO_Three, Li_TwoO-Al_TwoO_Three-SiO_Two, Na_TwoO-
Al_TwoO_Three-SiO_Two, Li_TwoO-GeO_Two, CdO-
PbO-SiO_Two, Li_TwoO-SiO_Two, B_TwoO_Three-B
i_TwoO_Three, PbO-SiO_Two-BaO, Na_TwoO-Pb
O-SiO_TwoPbO-GeO _TwoBoric glass, lead, etc.
Glass, bismuth glass, cadmium glass, glass
CuO, Bi, etc._TwoO_Three, B
_TwoO_Three, CdO, Li_TwoO, PbO, WO_Three, Pb_FiveG
e_ThreeO₁₁, Li_TwoSiO_ThreeAnd Li, and Li
F, CuF_Two, ZnF_Two, CaF_TwoAnd the like.

When sintering the inorganic dielectric compound particles,
Generally, particle growth and control of electrical properties of a sintered body are performed by the action of additives. In the present invention, however, various conventionally known additives may be used for the same purpose. it can. As porous inorganic dielectric particles,
As described above, those having an average particle size of 5 to 100 μm and an average specific surface area of 0.3 to 7.0 m ² / gr are preferable. However, when the primary particles are aggregated into secondary particles, The particle size is, for example, about 0.1 to 5 μm.
This is, when the particles are spherical, d (particle size of primary particles),
ρ (true specific gravity of primary particles), Sw (specific surface area of secondary particles)
This is because d has a relationship of d = 6 / (ρ × Sw). Therefore, for example, in the case of barium titanate, the particle size of the primary particles is about 0.14 to 3.3 μm.

PPO as a resin used in the present invention
Is, for example, the general formula

[0020]

Embedded image

[Where R is hydrogen or a group having 1 to 3 carbon atoms;
Wherein each R may be the same or different. And poly (2.6-dimethyl-1-4-phenylene oxide) as an example. Such a PPO can be synthesized, for example, by the method disclosed in US Pat. No. 4,059,568. Although not particularly limited, for example, when the weight average molecular weight (Mw) is 50,0
A polymer having a molecular weight distribution Mw / Mn = 4.2 (Mn is a number average molecular weight) is preferably used.

Examples of the crosslinkable polymer include, but are not limited to, 1,2-polybutadiene, 1,4-polybutadiene, styrene-butadiene copolymer, and modified 1,2-polybutadiene (male-modified, acrylic-modified). , Epoxy modified), rubbers and the like,
Each is used alone or in combination of two or more. The polymer state may be an elastomer or a rubber, but is preferably a high-molecular-weight rubber from the viewpoint of improving film formability.

From the viewpoint of improving the film formability of the PPO-based resin composition, it is preferable to use polystyrene within a range that does not hinder the achievement of the object of the present invention. Note that polystyrene having a high molecular weight is desirable because it improves film formability. Examples of the crosslinkable monomer include acrylic acids such as ester acrylates, epoxy acrylates, urethane acrylates, ether acrylates, melamine acrylates, alkyd acrylates, silicon acrylates, triallyl cyanurate, triallyl isocyanurate, and the like. Examples include polyfunctional monomers such as ethylene glycol dimethacrylate, divinylbenzene and diallyl phthalate, monofunctional monomers such as vinyl toluene, ethyl vinyl benzene, styrene and paramethylstyrene, and polyfunctional epoxies. Although used in combination with the above, it is not particularly limited to these.

As the crosslinkable monomer, triallyl cyanurate and / or triallyl isocyanurate are used because they have good compatibility with PPO and have good film-forming properties, crosslinking properties,
It is preferable in terms of heat resistance and dielectric properties. In addition, an initiator is usually added to the PPO-based resin composition. As the initiator, dicumyl peroxide, tert-
Butylcumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3,2.5-dimethyl-2
.5-di- (tert-butylperoxy) hexane, α.
α'-bis (tert-butylperoxy-m-isopropyl) benzene [1.4 (or 1.3) -bis (tert-
Butyl peroxyisopropyl) benzene], biscumyl of NOF Corporation, etc., each of which is used alone or in combination of two or more, but is not limited thereto.

The mixing ratio of the above-mentioned raw materials is not particularly limited, but PPO is not less than 7% by weight based on the total amount of PPO, the crosslinkable polymer and / or the crosslinkable monomer, and the initiator optionally added. , Less than 93% by weight of crosslinkable polymer and / or crosslinkable monomer and 0.1% of initiator.
The content is preferably 1 to 5% by weight. If the ratio is out of this range, the film forming property of the PPO-based resin composition may deteriorate, and the sheet may not be obtained as described below. More preferably, PPO is 7 to the total amount.
% By weight, less than 93% by weight of crosslinkable polymer, 70% by weight or less of crosslinkable monomer, 0.1 to 5% by weight or less of initiator, still more preferably 10% by weight or more of PPO, 20% by weight or less of polymer, 6 crosslinkable monomers
0% by weight or less, initiator in the range of 0.5 to 3% by weight.

The raw materials obtained by the above mixing are usually dissolved in a solvent (solvent) and mixed (solution mixing). At this time, a coupling agent may be used according to a usual method. This is to improve the adhesion between the inorganic filler and other resin components (including monomers), and to improve the physical properties of the final product. When dissolved in a solvent, PPO
The resin solid content of the resin composition is 10 to 3 with respect to the solvent.
It is preferably in the range of 0% by weight. After mixing, the solvent is removed to obtain a PPO-based resin composition. Examples of the solvent include halogenated hydrocarbons such as trichloroethylene, trichloroethane, chloroform, and methylene chloride; aromatic hydrocarbons such as chlorobenzene, benzene, toluene, and xylene; acetone; and carbon tetrachloride.
Particularly, trichloroethylene is preferable, and these can be used alone or in combination of two or more.
It is not limited to these. The mixing may be performed by another method.

In manufacturing a printed circuit board, a reinforcing material is usually used to improve mechanical strength and dimensional stability. Cross-shaped reinforcement,
A mat-like reinforcing material, a fiber-like reinforcing material, and the like can be given.
Reinforcing materials include inorganic materials and organic materials, and examples thereof include glass materials, ceramic materials such as alumina and zirconia, cloths, mats, and fibers made of organic materials such as polyethylene and polyamide. Cloths and mats
Normally, the thickness is about 15 μm to 1.5 mm, and the fiber diameter is 0.5 to 2.
Use the one of about 0 μm. The fiber is typically 2
A fiber having a diameter of about 0 to 300 μm and a fiber diameter of about 2 to 50 μm is used.

In the present invention, the mixing ratio of the matrix resin and the porous inorganic dielectric particles is usually 25:
~ 95 vol% (vol%), porous inorganic dielectric particles:
75 vol%, and when a reinforcing material is used, the reinforcing material is 0 to 7
It is in the range of 0 vol%. The composite dielectric of the present invention is manufactured, for example, as follows. For example, a PPO-based resin composition is obtained by dissolving and mixing the above-described raw materials in a solvent, and then casting or applying the PPO-based resin composition to a suitable one to form a thin layer, followed by drying to remove the solvent. (Casting method) to obtain a solidified product. According to this casting method, a solidified product composed of a PPO-based resin composition can be produced at a low temperature without using the costly calendering method. Normal,
In such a casting method, the solidified material becomes a sheet (film), but the solidified material is not limited to a sheet. The solidified product includes a cured product.

The casting method will be described in more detail. For example, a PPO resin composition or a solution obtained by dissolving the raw materials in a solvent is mixed on a mirror-finished iron plate or a carrier film for casting, for example, in a range of 5 to 700 ( Preferably, the sheet is cast (or coated) to a thickness of 5 to 500) μm, sufficiently dried, and the solvent is removed to obtain a sheet. Here, the sheet includes what is called a film, a film, a tape, and the like, and there is no particular limitation on the spread of the surface orthogonal to the thickness direction and the length, and the thickness is variously set according to the application. It is possible to The casting carrier film is not particularly limited, but is preferably a film insoluble in the solvent such as a polyethylene terephthalate (hereinafter abbreviated as “PET”) film, a polyethylene film, a polypropylene film, and a polyimide film. Those which have been subjected to mold treatment are preferred. The solvent is removed from the PPO-based resin composition solution cast (or applied) on the casting carrier film by air drying and / or drying with hot air. The set temperature during drying is preferably such that the upper limit is lower than the boiling point of the solvent or lower than the heat resistant temperature of the carrier film for casting (when drying is performed on the carrier film for casting), and the lower limit is the lower limit for drying. It is determined by time and processability. For example, using trichloroethylene as a solvent, PET
When the film is used as a carrier film for casting, the temperature is preferably in the range from room temperature to 80 ° C. If the temperature is increased within this range, the drying time can be reduced.

A sheet comprising the PPO-based resin composition and / or a substrate impregnated with a mixture of the PPO-based resin composition and the porous inorganic dielectric particles (hereinafter referred to as “prepreg”)
) Facilitates production of a laminate having a desired thickness. The sheet made of the PPO-based resin composition of the present invention is used for various applications such as an adhesive sheet as well as a laminate.

The prepreg may be made by any method. In the case of preparing a prepreg, the resin does not have to be melted, so that it can be more easily performed at a relatively low temperature.
The printed circuit board (including a laminate) according to the present invention.
No metal foil on both sides, metal foil on one or both sides)
Is produced, for example, as follows, but is not limited thereto. If the material to be used is a casting sheet prepared as described above, it is sufficiently dried at a temperature lower than the decomposition temperature of the compounded initiator and higher than the boiling point of the solvent used to eliminate the residual solvent. Keep it. This sheet and / or the prepregs prepared as described above are combined into a predetermined number of sheets so as to have a predetermined design thickness, and if necessary, a metal foil is also combined and laminated, and heated and pressed to melt the resin. A laminate is obtained by adhering the sheets together, the sheet and the prepreg, the prepregs, the sheet and the metal foil, and the prepreg and the metal foil. Strong adhesion is obtained by this fusion, but if a crosslinking reaction is carried out by a radical initiator by heating at this time, stronger adhesion can be obtained. The cross-linking reaction may be performed by ultraviolet irradiation or the like. When thermal crosslinking and photocrosslinking are not performed, crosslinking by radiation irradiation may be performed. Further, after thermal crosslinking and photocrosslinking have been performed, crosslinking may be performed by irradiation with radiation. Therefore, excellent heat resistance bonding can be realized between the sheets, between the prepregs, between the sheet and the prepreg, between the sheet and the metal foil, and between the prepreg and the metal foil.

Here, the combination of the sheet and the prepreg is not particularly limited, but a vertically symmetric combination is preferable from the viewpoint of preventing warpage after molding or secondary processing (etching or the like). Note that it is preferable to combine the sheet so as to come to the bonding interface with the metal foil from the viewpoint of improving the adhesive strength. Since the bonding between the metal foil and the sheet can utilize the heat-fusing property of the sheet, the laminating pressing temperature is preferably equal to or higher than the glass transition point of the sheet and approximately in the range of about 160 to 300 ° C. In the cured product of the PPO-based resin composition, a small amount of resin flows before curing, so that the PPO-based resin composition exhibits good fusion property to metal.
However, an adhesive may be used in combination.

As the metal foil, a copper foil, an aluminum foil or the like is used. Pressing is performed for the purpose of sheet-to-sheet, sheet-to-prepreg, prepreg-to-sheet, metal foil-to-sheet, metal foil-to-prepreg joining, and thickness adjustment of the laminate.
The pressing conditions are selected as needed. At the same time, conditions are set so as not to crush the inorganic filler. When the crosslinking is carried out by heating, the crosslinking reaction depends on the reaction temperature of the initiator used and the like, so that the heating temperature may be selected according to the type of the initiator. The heating time may be selected according to the type of the initiator and the like. For example, a temperature of 150 to 300 ° C. and a pressure of 20 kg / cm
^{2. The} time is about 10 to 60 minutes. A predetermined number of sheets and / or prepregs may be heated and laminated in advance, and a metal foil may be overlapped on one side or both sides thereof and heated and pressed again. The thickness of the printed circuit board is usually about 0.1 to 2 mm.

The solidified product (for example, a sheet) of the PPO-based resin composition thus produced is subjected to thermal crosslinking using a radical initiator, photocrosslinking, crosslinking using radiation, and the like. Further, tensile strength, impact strength, burst strength, heat resistance, and the like can be increased. The composite dielectric and the printed circuit board thus obtained do not impair the PPO characteristic of low dielectric loss, and have excellent high-frequency characteristics such as dielectric characteristics and various physical properties such as heat resistance. The dimensional stability is also excellent. And the manufacturing operation of the printed circuit board is also simple as described above.

The scope of the present invention is not limited to the above-exemplified compounds, numerical ranges and processing methods. Its use is not limited to capacitors.

[0036]

In the composite dielectric and printed circuit board according to the present invention, the inorganic dielectric particles contained in the composite dielectric are porous. If the composite dielectric in which the porous particles are dispersed and the composite dielectric in which the non-porous particles are dispersed have the same weight ratio of the particles in the composite dielectric, the two composite dielectrics In
Both the porous particles and the non-porous particles have the same true volume ratio, but in the former (a composite dielectric in which the porous particles of the present invention are dispersed), the porous inorganic dielectric particles are swollen by voids. And present in the composite dielectric, the apparent volume of the particles occupying the inorganic dielectric is larger than the latter (the composite dielectric in which non-porous particles are dispersed). Since it is considered that the void portion of the porous inorganic dielectric particles also acts as a high dielectric constant region, the dielectric constant of the composite dielectric of the present invention is effectively improved.

The porous inorganic dielectric particles are less likely to sink in the resin and cause less sedimentation than non-porous inorganic dielectric particles of the same size, thereby facilitating the production of a composite dielectric. In the case of processing (cutting, opening a hole, etc.) a circuit substrate, the substrate is easily broken as compared with a non-porous inorganic dielectric having the same particle size, so that the processed surface is good and processing consumables are less deteriorated.

Furthermore, since the PPO resin composition is used as the resin component, crosslinking can be easily generated, and the tensile strength, impact strength, burst strength, and heat resistance can be greatly increased. it can.

[0039]

EXAMPLES Next, specific examples of the present invention will be described. -Comparative Example 1-BaTi _0.7 Zr _0.3 O ₃ powder 5 having an average particle size of 0.1 µm 5
00 g, 2.5 g of borosilicate glass (manufactured by Iwaki Glass) and 50 ml of a 5 wt% polyvinyl alcohol solution were thoroughly wet-mixed in 1 liter of ion-exchanged water, followed by spray granulation. Next, this was heat-treated at 1050 ° C. for 2 hours to obtain an average particle diameter of a plurality of primary particles of 20 μm and a specific surface area of 1: 1. Granules of 0 m ² / gr were obtained as porous inorganic dielectric particles.

Next, the porous BaTi _0.7 Zr
180 parts by weight (30 vol%) of _0.3 O ₃ particles , PP
The O-resin was weighed so as to be 74 parts by weight (70 vol%), and 300 parts by weight of tricrene (trichloroethylene manufactured by Toa Gosei Chemical Industry Co., Ltd.) was added and stirred. PPO using
The resin was completely dissolved and defoamed to obtain a varnish. After thoroughly stirring the varnish, the varnish was impregnated into a plain woven glass cloth (thickness: 100 μm, fiber diameter: 7 μm, woven density: 60 pieces / length, 25 pieces / 25 mm), and dried at 50 ° C. In the obtained varnish-impregnated glass cloth, PP
A mixture of O resin and BaTi _0.7 Zr _0.3 O ₃ particles
The ratio of glass cloth is resin / particle mixture : 73wt%
(About 70 vol%), glass cloth : 27 wt% (about 3 vol%)
0 vol%). Five varnish-impregnated cloths thus obtained are stacked, and copper foil (thickness: 17 μm) is placed on the top and bottom.
At a temperature of 250 ° C., a pressure of 33 kg / cm ² ,
The molding was carried out under pressure under molding conditions for 5 minutes to obtain a double-sided copper foil-clad printed circuit board.

Examples 1 to 6 The same procedures as in Comparative Example 1 were carried out except that the PPO resin composition having the raw materials shown in Table 1 was used as the resin component and the molding pressure was 30 kg / cm ^2. Thus, a printed circuit board with double-sided copper foil was obtained. Also in this case, the PPO resin and the porous Ba are used.
The volume ratio of the Ti _0.7 Zr _0.3 O ₃ particles was 70:30. In this case, heat fusion and crosslinking occur simultaneously during molding.

[0042]

[Table 1]

In Table 1, SBS is styrene butadiene copolymer, TAIC is triallyl isocyanurate, p-TAIC is TAIC polymer, and A is 2
* 5-dimethyl-2.5-di- (tert-butylperoxy) hexyne-3 is respectively represented. The 2.5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3 used was Perhexin 25B manufactured by NOF Corporation.

Comparative Example 2 BaTi having an average particle size of 1 μm and a specific surface area of 1.8 m ² / gr
_A double-sided copper foil-clad printed circuit board was obtained in the same manner as in Comparative Example 1, except that _0.7 Zr _0.3 O ₃ powder was used as inorganic dielectric particles as they were. Comparative Example 3 An FR-4 epoxy glass laminate (CCL) was manufactured using the same porous BaTi _0.7 Zr _0.3 O ₃ as the porous inorganic dielectric particles as in Comparative Example 1. In this case, the volume ratio between the resin and the particles was 70:30, and the volume ratio between the resin / particle mixture and the glass cloth was 70:30.

The relative permittivity, dielectric loss tangent (tan δ), peel strength, and solder heat resistance of each of the obtained substrates were examined, and the results are shown in Table 2.

[0046]

[Table 2]

As shown in Table 2, Examples 1 to 6 and Comparative Example 1 using PPO resin and porous inorganic dielectric particles were used.
The printed circuit board substrate of Comparative Example 2 using non-porous inorganic dielectric particles or the PPO substrate of Comparative Example 2
In comparison with the printed circuit board substrate of Comparative Example 3 in which no resin is used, the relative dielectric constant is sufficiently large and tan δ is sufficiently within a practical range. Since the printed circuit board substrates of Examples 1 to 6 are crosslinked by blending a crosslinking agent with PPO, the printed circuit board substrates of Comparative Example 1 having no such crosslinking are more heat-resistant. Excellent in properties and dimensional stability. This means that the composite dielectric used for the printed circuit board according to the present invention has excellent performance.

The porous inorganic dielectric particles used in the examples were sintered using a borosilicate glass as a sintering aid. According to the measurement, the particle strength was 7.2 kg / mm. ^{Was 2} . For reference, porous BaTi _0.7 Zr _0.3 O obtained without using borosilicate glass as a sintering aid
_When the physical properties of the sample No. ₃ were examined, the average particle size and the specific surface area were 20 μm and 1.0 μm, similarly to those of the porous BaTi _0.7 Zr _0.3 O ₃ used in the examples. 0 m ² / gr, but the grain strength was 3.
There was only 8 kg / mm ² . The particle strength was measured using a PCT strength tester manufactured by Shimadzu Corporation.

[0049]

As can be seen from the above description, the composite dielectrics according to claims 1 to 9 and the claims according to the present invention.
In the printed circuit boards of Nos. 10 to 11, since the inorganic dielectric particles are porous, the effect of improving the dielectric constant by the particles is effectively exhibited. Further, since the porous inorganic dielectric particles are less likely to sink in the resin and cause less sedimentation than non-porous inorganic dielectric particles having the same size, the production is easy. In addition, since it is porous, processing (cutting, opening of holes, etc.) is easy, and further, since a crosslinkable PPO-based resin composition is used as a resin component, crosslinking easily occurs, and tensile strength, Impact strength, burst strength, and heat resistance can be greatly increased.

In addition, in the composite dielectric material according to the fifth aspect, the porous inorganic dielectric particles have an average particle size of 5 to 100 μm and an average specific surface area of 0.3 to 7.0 m ² / gr. The effect of improving the dielectric constant is more remarkably exhibited. In the composite dielectric material according to the sixth aspect, the porous inorganic dielectric particles are secondary particles obtained by assembling primary particles, and the porous particles are easily manufactured. As a result, the composite dielectric material is manufactured. It is easy.

In the composite dielectric according to the seventh aspect, the primary particles of the porous inorganic dielectric particles are bonded to each other by sintering, so that the effect of improving the dielectric constant is more remarkably exhibited. In the composite dielectric according to the eighth aspect, since the strength of the porous inorganic dielectric particles is improved, the particles are not broken in the composite process, stable performance can be expected, and the production of the particles becomes easy.

According to the ninth aspect of the present invention, since the porous inorganic dielectric particles are made of a compound having a perovskite crystal structure, the effect of improving the dielectric constant is more remarkably exhibited.
In the printed circuit board according to the eleventh aspect, since the printed circuit board is reinforced with the reinforcing material, mechanical properties such as dimensional stability are further improved.

[Brief description of the drawings]

FIG. 1 is a magnification of 2 showing a state in which porous inorganic dielectric particles are dispersed in a resin in a composite dielectric according to the present invention.
It is a scanning electron microscope photograph of 500 times.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kiyotaka Komori 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. Inside (56) References JP-A 1-245059 (JP, A) JP-A 1-205411 ( JP, A) JP-A-1-179777 (JP, A) JP-A-49-17806 (JP, A) JP-A-63-127515 (JP, A) JP-A-5-94717 (JP, A) 49-25159 (JP, B1) JP-B 54-18754 (JP, B2)

Claims (8)

(57) [Claims] 1. In a resin , primary particles are mutually sintered by sintering.
Average particle size of 5 to 100 μm, which is secondary particles formed by bonding,
A composite dielectric in which porous inorganic dielectric particles having an average specific surface area of 0.3 to 7.0 m ² / gr are dispersed, wherein the resin comprises polyphenylene oxide and a crosslinkable polymer and / or a crosslinkable monomer. A composite dielectric comprising a polyphenylene oxide-based composition comprising: 2. The composition of the resin is not less than 7% by weight of polyphenylene oxide and less than 93% by weight of cross-linkable polymer and / or cross-linkable monomer, based on the total amount of polyphenylene oxide and cross-linkable polymer and / or cross-linkable monomer. 2. The composite dielectric according to claim 1, wherein: 3. The crosslinkable polymer is at least one selected from the group consisting of 1.2 polybutadiene, 1.4 polybutadiene, styrene butadiene copolymer, modified 1.2 polybutadiene, and rubbers. 2. The composite dielectric according to item 2. 4. The crosslinking monomer is an ester acrylate, an epoxy acrylate, a urethane acrylate, an ether acrylate, a melamine acrylate, an alkyd acrylate, a silicon acrylate, a triallyl cyanurate, a triallyl isocyanurate, or ethylene glycol. 4. The method according to claim 1, which is at least one selected from the group consisting of dimethacrylate, divinylbenzene, diallylphthalate, vinyltoluene, ethylvinylbenzene, styrene, paramethylstyrene and polyfunctional epoxies. A composite dielectric as described. 5. The composite dielectric according to claim 1, wherein the sintering is performed by adding a sintering aid. 6. A porous inorganic dielectric particles, composite dielectric according to claim 1 comprising a compound having a perovskite crystal structure to 5. As 7. dielectric material, the printed circuit board composite dielectric is used according to any one of claims 1 to 6. 8. The printed circuit board according to claim 7, which is reinforced with a reinforcing material.