JP3400416B2 - Composite dielectric substrate - 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 substrate used for electronic parts and laminated circuits, and more particularly to a composite dielectric substrate containing glass cloth.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable trend toward miniaturization and high density of mounting methods in the field of electronic devices for communication, consumer use, industrial use, etc. Electrical characteristics, moldability, reduction in size and weight, and speeding up are being demanded. In particular, the frequency range of radio waves used for mobile communication such as mobile phones, satellite broadcasting, and satellite communication equipment is
The high frequency range of several GHz is used.

Amid the rapid development of these communication and broadcasting equipments, miniaturization and high-density mounting of housings, substrates and electronic parts are required. Generally, the wavelength of a signal propagating through an electronic component or a substrate can be expressed by the following equation. Wavelength = c / (f × ε ^1/2 ) c: speed of light f: frequency ε: permittivity

That is, the larger the dielectric constant of the material, the shorter the wavelength, and the smaller the area occupied by the transmission line, and the more compact the substrate and the product. Also a circuit board,
In many cases, a capacitor is built in an electronic component, and a high dielectric constant material is required to reduce the size of such a capacitor.

However, it is extremely difficult for a resin material to obtain a sufficient dielectric constant by itself. Therefore, an electronic component that simply uses a resin material cannot obtain sufficient characteristics and has a large shape, and it is difficult to reduce the size and thickness.

Further, a method of compositing a ceramic powder with a resin material is also disclosed in, for example, Japanese Patent Application Laid-Open No. 8-69712, but sufficient high frequency characteristics have not been obtained. In addition, no specific study on the material for wavelength shortening has been made.

Furthermore, it is difficult to increase the permittivity of a substrate or prepreg containing glass cloth.
When the thickness of the substrate is reduced to improve the dielectric constant,
The volume occupied by the glass cloth becomes large, and as a result, it was difficult to improve the dielectric constant as expected.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to increase the dielectric constant of a composite dielectric substrate having at least a resin and a glass cloth, and a prepreg, thereby making it possible to reduce the size and weight of the substrate and electronic parts. A composite dielectric substrate and a prepreg are provided.

Another object of the present invention is to provide a composite dielectric substrate and a prepreg capable of reducing the size of a built-in capacitor.

[0010]

The above object can be achieved by the present invention described below. (1) At least a resin, a dielectric powder dispersed in the resin, and a glass cloth are included, and the dielectric constant of the mixture of the resin and the dielectric powder is equal to or higher than the dielectric constant of the glass cloth. The glass cloth has a thickness of 70 μm or less, a cloth weight of 60 g / m ² or less, an air permeability of 300 cm ³ / cm ² / sec or more, and a composite dielectric obtained by curing a prepreg having a thickness of +10 to +50 μm with respect to the glass cloth. Body board. (2) The dielectric powder has a dielectric constant of 10 to 20000.
In the above (1), the content of the resin is 20 to 60% by volume.
Composite dielectric substrate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The composite dielectric substrate of the present invention comprises at least a resin,
A dielectric powder dispersed in this resin, and a glass cloth, wherein the dielectric constant of the mixture of the resin and the dielectric powder is not less than the dielectric constant of the glass cloth, and the glass cloth has a thickness of 70 μm or less. , Cloth weight 60g / m ² or less, ventilation rate 3
It is a composite dielectric substrate in which a prepreg having a thickness of 00 cm ³ / cm ² / sec or more and a thickness of +10 to +50 μm with respect to the glass cloth is cured.

As described above, the weight of the cloth and the air permeability of the glass cloth contained in the substrate and the prepreg in which the dielectric constant of the mixture of the resin and the dielectric powder is equal to or higher than the dielectric constant of the glass cloth, and in particular the air permeability is set to a predetermined value. With the above, the dielectric constants of the substrate and the prepreg can be improved, and the size and weight of the device can be reduced.

The composite dielectric substrate and prepreg of the present invention are
Especially frequency 100MHz or more, especially 100MHz to 10GHz
Suitable for use in high frequency band.

[0014] Glass cloth used in the present invention, fabric weight (basis weight) of 60 g / m ² or less, in particular 15 to 60 g / m ^2. When the cloth weight exceeds 60 g / m ² , it becomes difficult to manufacture a thin substrate and a prepreg for realizing a small size and a light weight.

The air permeability of the glass cloth is 300 cm ³ / cm ² /
sec or more, preferably 300 to 500 cm ³ / cm ² / sec. By setting the air permeability of the glass cloth to 300 cm ³ / cm ² / sec or more, the resin material easily enters between the fibers of the glass cloth, and the dielectric constants of the substrate and prepreg can be improved.

The material of the glass cloth may be various according to the purpose and use, and a commercially available product can be used as it is. The glass cloth at this time was E glass cloth (ε = 7, tan δ = 0.
003, 1 GHz), D glass cloth (ε = 4, tanδ
= 0.0013, 1 GHz), H glass cloth (ε = 1)
1, tan δ = 0.003, 1 GHz), S glass cloth, etc. can be used properly, and among them, E glass cloth is preferable. In addition, a coupling treatment or the like may be performed to improve the interlayer adhesion.

The thickness of the glass cloth is preferably 70 μm or less, more preferably 20 to 60 μm. The thickness of the thread used is 12 tex or less, and particularly preferably about 2.8 to 5.6 tex.

The obtained substrate and prepreg preferably have a thickness of +10 to +50 μm with respect to the glass cloth.

The resin used in the present invention is not particularly limited, and can be appropriately selected and used from resin materials excellent in moldability, workability, adhesiveness during lamination, and electrical characteristics. Either a thermosetting resin or a thermoplastic resin may be used.

As the thermosetting resin, epoxy resin, phenol resin, unsaturated polyester resin, vinyl ester resin, polyimide resin, polyphenylene ether (oxide) resin, bismaleimide triazine (cyanate ester) resin, fumarate resin, polybutadiene resin, Examples thereof include polyvinyl benzyl ether resin.
Examples of the thermoplastic resin include aromatic polyester resins, polyphenylene sulfide resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene sulfide resins, polyether ether ketone resins, polytetrafluoroethylene resins, graft resins and the like. Among these, phenol resin, epoxy resin, low dielectric constant epoxy resin, polybutadiene resin, BT resin, polyvinyl benzyl ether resin and the like are particularly preferable as the base resin.

These resins may be used alone,
You may mix and use 2 or more types. When two or more kinds are mixed and used, the mixing ratio is arbitrary.

The dielectric powder used in the present invention is preferably a ceramic powder, and it may be any ceramic powder having a relative dielectric constant and Q larger than that of the resin used as the dispersion medium in the high frequency band, and two or more kinds may be used. .

Particularly, it is preferable that the ceramic powder used in the present invention has a relative dielectric constant of 10 to 20,000 and a dielectric loss tangent of 0.05 or less.

In order to obtain a relatively high dielectric constant, it is particularly preferable to use the following materials. Titanium-Barium-
Neodymium ceramics, titanium-barium-tin ceramics, lead-calcium ceramics, titanium dioxide ceramics, barium titanate ceramics, lead titanate ceramics, strontium titanate ceramics, calcium titanate ceramics, bismuth titanate. Series ceramics, magnesium titanate series ceramics, CaWO ₄ series ceramics, B
a (Mg, Nb) O ₃ based ceramics, Ba (Mg, T
a) O ₃ based ceramics, Ba (Co, Mg, Nb) O
₃ series ceramics, Ba (Co, Mg, Ta) O ₃ series ceramics. The titanium dioxide ceramics
In addition to those containing only titanium dioxide, those containing other small amounts of additives are also referred to and those in which the crystal structure of titanium dioxide is retained. The same applies to other ceramics. In particular, the titanium dioxide ceramics preferably have a rutile structure.

These may be used alone or in combination of two or more. When two or more kinds are mixed and used, the mixing ratio is arbitrary.

The particle size of the ceramic powder is 0.1 to 10 μm, especially 0.2, considering the kneading property with the resin.
It is preferably about 5 μm. When the particle size is small, the surface area of the powder is increased, the viscosity at the time of dispersion and mixing, and the thixotropy are increased, making it difficult to achieve a high filling rate and making it difficult to knead with the resin. Further, if the particle size becomes large, it becomes difficult to carry out uniform dispersion / mixing, and the sedimentation becomes intense, resulting in non-uniformity, and a dense molded body cannot be obtained when molding a composition having a large amount of powder content. .

Generally, the content of the ceramic is 20% by volume or more and less than 60% by volume, preferably 20% by volume or more and 50% by volume, when the total amount of the resin and the ceramics powder is 100% by volume. The range is as follows.

The ceramic powder may be a single crystal powder such as sapphire or a polycrystalline alumina powder, and the type of the ceramic powder including these is preferably, for example, a dielectric powder having the following composition as a main component. 2GH in total
The relative permittivity ε and the Q value at z are shown.

MgTiO₃[Ε = 17, Q = 2200
0], ZnTiO₃[Ε = 26, Q = 800], Zn₂T
iO_Four[Ε = 15, Q = 700], TiO₂[Ε = 10
4, Q = 15000], CaTiO₃[Ε = 170, Q
= 1800], SrTiO₃[Ε = 255, Q = 70
0], SrZrO₃[Ε = 30, Q = 1200], Ba
Ti₂O _Five[Ε = 42, Q = 5700], BaTi_FourO
₉[Ε = 38, Q = 9000], Ba₂Ti₉O₂₀[Ε =
39, Q = 9000], Ba₂(Ti, Sn)₉O₂₀[Ε
= 37, Q = 5000], ZrTiO_Four[Ε = 39, Q
= 7000], (Zr, Sn) TiO_Four[Ε = 38, Q
= 7000], BaNd₂Ti_FiveO₁₄[Ε = 83, Q = 2
100], BaSm₂TiO₁₄[Ε = 74, Q = 240
0], Bi₂O₃-BaO-Nd₂O₃-TiO₂System [ε =
88, Q = 2000], PbO-BaO-Nd₂O₃-T
iO₂System [ε = 90, Q = 5200], (Bi₂O₃, P
bO) -BaO-Nd₂O₃-TiO₂System [ε = 105,
Q = 2500], La₂Ti₂O₇[Ε = 44, Q = 40
00], Nd₂Ti₂O₇[Ε = 37, Q = 1100],
(Li, Sm) TiO₃[Ε = 81, Q = 2050],
Ba (Mg_1/3Ta_2/3) O₃[Ε = 25, Q = 3500
0], Ba (Zn_1/3Ta_2/3) O₃[Ε = 30, Q = 1
4000], Ba (Zn_1/3Nb_2/3) O₃[Ε = 41,
Q = 9200], Sr (Zn_1/3Nb_2/3) O₃[Ε = 4
0, Q = 4000].

More preferably, the main component is the following composition. TiO ₂ , CaTiO ₃ , SrTiO ₃ ,
BaO-Nd ₂ O ₃ -TiO ₂ system, Bi ₂ O ₃ -BaO-N
d ₂ O ₃ -TiO _{2 system, BaTi 4 O 9, Ba 2} Ti 9 O 20,
_{Ba 2 (Ti, Sn) 9} O 20 system, MgO-TiO ₂ system, Z
nO-TiO ₂ system, etc.

The content of the ceramic powder is 20 volume% or more and less than 60 volume% when the total amount of the resin and the ceramic powder is 100 volume%.
The preferred range is 20% by volume or more and 50% by volume or less.

If the ceramic powder is more than 60% by volume, a dense composition cannot be obtained. Further, Q may be greatly reduced as compared with the case where the ceramic powder is not added. On the other hand, when the ceramic powder is less than 20% by volume, the effect of containing the ceramic powder is not so remarkable.

In the electronic component of the present invention, each component is appropriately set within the above range, and the permittivity of the mixture of the resin and the dielectric powder is made higher than that of the glass cloth.
The effect of the present invention can be obtained.

The ceramic powder may be a single crystal or polycrystal powder.

In the present invention, a flame retardant may be contained if necessary. As the flame retardant, various flame retardants which are usually used for making the substrate flame retardant can be used.
Specifically, halides such as halogenated phosphoric acid esters and brominated epoxy resins, organic compounds such as phosphoric acid ester amides, and inorganic materials such as antimony trioxide and aluminum hydride can be used.

The metal foil to be used may be a metal foil having a good conductivity such as gold, silver, copper or aluminum. Of these, copper is particularly preferable.

As a method for producing the metal foil, various known methods such as electrolysis and rolling can be used. When the foil peel strength is desired, the electrolytic foil is used, and when high frequency characteristics are important. It is advisable to use a rolled foil that is less affected by the skin effect due to surface irregularities.

The thickness of the metal foil is preferably 8 to 70 μm, more preferably 12 to 18 μm.

In the present invention, in order to obtain a prepreg as a base for electronic parts, a paste containing a predetermined mixing ratio of ceramic powder, magnetic powder, and optionally a flame retardant and a resin, kneaded in a solvent to form a slurry. And dry (B
Follow the process of making a stage). The solvent used in this case is preferably a volatile solvent, particularly preferably the above polar neutral solvent, which is used for the purpose of adjusting the viscosity of the paste and facilitating coating. The kneading may be performed by a known method using a ball mill, stirring or the like. Apply the paste on the metal foil,
Alternatively, it can be formed by impregnating a glass cloth.

Drying of the prepreg (B stage conversion) may be appropriately adjusted depending on the contained ceramic powder and, if necessary, the content of flame retardant.
It may be 0.1 to 5 hours.

The prepreg can be manufactured by the method shown in FIG. 2 or FIG. In this case, the method of FIG. 2 is relatively suitable for mass production, and the method of FIG. 3 is characterized in that the film thickness can be controlled easily and the characteristics can be adjusted relatively easily. In FIG. 2, as shown in FIG. 2A, the glass cloth 101a wound in a roll shape is unwound from the roll 101a, and is guided by the guide roller 111.
It is conveyed to the coating tank 110 via. This coating tank 110
Contains a ceramic powder dispersed in a solvent, and optionally a flame retardant and a resin in a slurry form. When the glass cloth passes through the coating tank 110, the glass cloth is dipped in the slurry to form a glass cloth. While being coated,
The gap in it will be filled.

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

When cut into a predetermined size,
As shown in (b), a prepreg is obtained in which a ceramic powder and, if necessary, a resin 102 containing a flame retardant are arranged on both sides of a glass cloth 101.

Further, as shown in (c), a metal foil 103 such as a copper foil is arranged on both upper and lower surfaces of the obtained prepreg, and when this is heated and pressed, both surfaces as shown in (d) are obtained. A substrate with a metal foil is obtained. Heating and pressurizing condition is 10
Temperature of 0 to 400 ° 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 perform molding for 0.5 to 20 hours under such conditions. Molding can be performed in multiple stages by changing the conditions. When the metal foil is not provided, heating / pressing may be performed without disposing the metal foil.

Next, the manufacturing method of FIG. 3 will be described.
In FIG. 3, as shown in (a), ceramic powder,
Slurry 1 with flame retardant and resin dispersed in solvent if necessary
02a is coated on a metal foil such as a copper foil while keeping a constant clearance with a doctor blade 150 or the like.

When cut into a predetermined size,
As shown in (b), a prepreg is obtained in which the ceramic powder and, if necessary, the resin 102 containing a flame retardant are arranged on the upper surface of the metal foil 103.

Further, as shown in (c), the metal foil 103 obtained in (b) is formed on both upper and lower surfaces of the glass cloth 101.
When the attached prepregs are arranged with the resin 102 side as the inner surface and are heated and pressed, a double-sided metal foil-coated substrate as shown in (d) is obtained. The heating and pressing conditions may be the same as above.

Examples of such a substrate with a copper foil include a double-sided patterning substrate and a multilayer substrate.

4 and 5 show process diagrams of an example of forming a double-sided patterned substrate. As shown in FIGS. 4 and 5, a prepreg 1 having a predetermined thickness and a copper (Cu) foil 2 having a predetermined thickness are overlapped and heated under pressure to be molded (step A). Next, a through hole is formed by drilling (step B). Copper (Cu) plating is applied to the formed through holes to form a plated film 4 (step C). Further, the copper foils 2 on both sides are patterned to form a conductor pattern 21 (step D). Then, as shown in FIG. 4, plating for connecting external terminals and the like is performed (step E). The plating in this case 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.

FIG. 6 and FIG. 7 are process diagrams of an example of forming a multilayer substrate, showing an example in which four layers are laminated. As shown in FIG. 6 and FIG. 7, a prepreg 1 having a predetermined thickness and a copper (Cu) foil 2 having a predetermined thickness are overlapped and heated under pressure to be molded (step a). Next, the copper foils 2 on both sides are patterned to form a conductor pattern 21 (step b). On both sides of the double-sided patterned substrate thus obtained, a prepreg 1 and a copper foil 2 each having a predetermined thickness are further stacked and simultaneously heated and pressed to form (step c). Next, a through hole is formed by drilling (step d). Copper (Cu) plating is applied to the formed through holes to form a plated film 4 (step e). Further, the copper foils 2 on both sides are patterned to form a conductor pattern 21 (step f). After that, as shown in FIG. 6, plating for connection with external terminals is performed (step g). The plating in this case 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 above heating and pressing molding conditions are 100 to 4
Temperature of 00 ° C., 9.8 × 10 ^{5 to} 7.84 × 10 ⁶ Pa (1
The pressure is preferably 0 to 80 kgf / cm ² and the time is preferably 0.5 to 20 hours.

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

An electronic component can be obtained by combining such a prepreg, a substrate with a copper foil, a laminated substrate and the like with an element configuration pattern and a configuration material.

[0054]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention. [Dielectric powder surface treatment] Dielectric powder (TiBaO ₃ system,
400 g of ε = 15000 and average particle size = 1.5 μm) was placed in a beaker containing 500 g of water and stirred by a stirrer. A silane coupling agent (trade name: TSL-
8113, Toshiba Silicone), and stirred for 1 hour. Then, let stand for 1 hour, separate the dielectric powder,
It was dried at 110 ° C. for 16 hours.

[Preparation of Compound Slurry] As a base resin, polyvinyl benzyl ether compound: tetrabromobisphenol A-modified vinyl benzyl resin = 7: 3 was added as 5
5 g and 45 g of toluene were stirred in the same container until completely dissolved to prepare a solution having a solid content of 55 wt%.
Into this, the dielectric powder 193.
3 g was added and the mixture was diffused until completely dispersed to prepare a compounded slurry having a resin: barium titanate = 6: 4 by volume ratio.

[Preparation of prepreg containing glass cloth] The glass cloth shown in Table 1 (106 type, thickness 39 μm,
Asahi Shabel Co., Ltd.) is impregnated and coated with the above-prepared compounding solution, and subjected to temporary curing treatment at 110 ° C. for 15 minutes,
A prepreg containing a glass cloth was obtained. The obtained thickness was 60, 70, 80, 90 μm.

[Preparation of Laminated Plate Containing Glass Cloth] Four prepregs as described above were stacked and a temperature profile of 120 ° C. 30
Minutes, heating at 180 ° C. for 90 minutes at a pressure of 300 MPa and pressure curing to obtain a glass cloth-containing laminated plate. Thickness is 24
It was 0, 280, 320, 360 μm. In the same manner, glass cloth-containing laminated plate samples of Example 2 to Comparative Example 2 described in Table 1 were produced.

[0058]

[Table 1]

Each of the produced samples had a length of 90 mm and a width of 0.
It was cut into 7 mm and used as an evaluation sample. The dielectric constant and Q value (dielectric loss tangent) at 2 GHz were measured for this evaluation sample. The results are shown in Fig. 1.

As is apparent from FIG. 1, as the air permeability of the glass cloth increases, the dielectric constant of the substrate increases. For example, when the thickness of the prepreg is 60 μm, ε = 15.0 for a sample using glass cloth having an air permeability of 95 cm ³ / cm ² / sec, but an air permeability of 300 cm ³ /
ε = 1 for samples using glass cloth of cm ² / sec
It was improved to 9.5. In addition, the thickness of the prepreg is 90 μm
, The air permeability of 80 cm ³ / cm ² / sec in the sample using glass cloth was ε = 17.4, but the air permeability was 3
In the sample using the glass cloth of 00 cm ³ / cm ² / sec, ε was improved to 21.1.

[0061]

As described above, according to the present invention, the permittivity of the composite dielectric substrate having at least the resin and the glass cloth and the prepreg is increased, and the size and weight of the substrate and electronic parts can be reduced. A composite dielectric substrate and a prepreg can be provided.

Further, it is possible to provide a composite dielectric substrate and a prepreg capable of miniaturizing the built-in capacitor.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the air permeability and the dielectric constant of glass cloth.

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

FIG. 3 is another process drawing showing an example of forming a substrate with a copper foil used in the present invention.

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

FIG. 5 is another process drawing showing an example of forming a substrate with a copper foil.

FIG. 6 is a process drawing showing an example of forming a multilayer substrate.

FIG. 7 is a process chart showing an example of forming a multilayer substrate.

[Explanation of symbols]

1 prepreg 2 Copper foil coating 3 through holes 4 plating film 10 Double-sided copper foil board (double-sided copper clad board) 21 copper foil 21 conductor pattern

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H05K 3/46 H05K 3/46 T // C08L 101: 00 C08L 101: 00 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 5/24 CEZ H05K 1/03

Claims (2)

(57) [Claims] 1. At least a resin, a dielectric powder dispersed in the resin, and glass cloth, wherein the dielectric constant of the mixture of the resin and the dielectric powder is equal to or higher than the dielectric constant of the glass cloth. The glass cloth has a thickness of 70 μm or less and a cloth weight of 60 g /
A composite dielectric substrate obtained by curing a prepreg having a thickness of +10 to +50 μm with respect to the glass cloth, having a m ² or less, an air permeability of 300 cm ³ / cm ² / sec or more. 2. The dielectric powder has a dielectric constant of 10 to 200.
The composite dielectric substrate according to claim 1, wherein the content is 00 to 20 to 60% by volume with respect to the resin.