JP2006252891A - Complex dielectric material, prepreg using the same, metal foil coated product, molded article, complex dielectric base plate, and multi-layer base plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new complex dielectric material capable of sufficiently reflecting high relative dielectric constant εr of ceramic, capable of realizing unprecedentedly high relative dielectric constant εr, having small rate of change by temperature of relative dielectric constant εr. <P>SOLUTION: The complex dielectric material is composed of dielectric ceramic and organic polymeric material. The dielectric ceramic contains an oxide having positive rate of change by temperature of relative dielectric constant, having a composition expressed by general formula; Ag(Nb<SB>1-x</SB>Ta<SB>x</SB>)O<SB>3</SB>(wherein, 0.10≤x≤0.45). Further, an oxide having negative rate of change by temperature of relative dielectric constant, having a composition expressed by general formula; Ag(Nb<SB>1-x</SB>Ta<SB>x</SB>)O<SB>3</SB>(wherein, 0.60≤x≤0.90) may be used in combination. The complex dielectric material is used for a prepreg, a metal foil coated product, and a plate-shaped molded article or the like to manufacture a complex dielectric base plate and multi-layered base plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite dielectric material in which a dielectric ceramic and an organic polymer material are combined, and relates to a novel composite dielectric material using Nb, Ta and Ag oxides as the dielectric ceramic. Furthermore, the present invention relates to a prepreg suitable for a circuit board material using such a composite dielectric material, a metal foil coated product, a molded product, a composite dielectric substrate, and a multilayer substrate.

  For example, in the information communication field, the use frequency band tends to shift to a high frequency, and high frequency in the gigahertz (GHz) band is used in mobile communication such as satellite broadcasting, satellite communication, mobile phone and car phone. Yes.

  In circuit boards and electronic components mounted on devices used in the high frequency band as described above, the dielectric material to be used needs to be a low loss material having high Q and excellent high frequency transmission characteristics. Furthermore, in order to achieve high performance and miniaturization of circuit boards and electronic components, a dielectric material having a high relative dielectric constant εr in the used frequency band is required. In particular, the point of miniaturization is based on the principle that the wavelength of the electromagnetic wave in the dielectric material is shortened by 1 / √εr, and the smaller the dielectric material having a higher relative dielectric constant εr, the smaller the circuit board or electronic component. Is possible. In addition, since there is a demand for a substrate having a capacitor function, a high dielectric constant substrate using such a dielectric material is also required.

  Dielectric ceramics, which are inorganic materials, are widely used as dielectric materials, and dielectric ceramics having various compositions according to required characteristics have been developed. However, when the dielectric ceramic is used for a circuit board or an electronic component, it is generally used in the form of a bulk sintered body, and since firing at a high temperature is necessary, there is a problem that the application range is restricted. is there. In addition, shrinkage and deformation that occur in the baking process at high temperatures, and further deterioration of characteristics due to oxidation of the internal conductor, for example, become a problem.

  Under such circumstances, a composite dielectric material in which a dielectric ceramic powder and an organic polymer material are combined has been proposed (see, for example, Patent Document 1 and Patent Document 2). Since composite dielectric materials do not require firing at high temperatures, they can be used in a wide range of applications. Shrinkage and deformation during the firing process, one of the manufacturing processes for bulk sintered bodies, and deterioration of internal conductor properties There is no problem. In addition, since the organic polymer material is contained, the degree of freedom of shape workability is increased, the weight is light, and the relative permittivity εr and the like can be arbitrarily changed depending on the blending ratio of the dielectric ceramic powder.

For example, the invention described in Patent Document 1 discloses a composite dielectric in which a ceramic such as a BaTiO ₃ system is dispersed in a resin (polyvinyl benzyl ether compound). In the invention described in Patent Document 1, a relative dielectric constant of 10 or more is realized in a high frequency band of 10 MHz or more by setting the ceramic content to 30% by volume or more.

On the other hand, Patent Document 2 relates to a composite material for a dielectric electromotive force antenna, and a dielectric ceramic having a positive relative dielectric constant temperature change characteristic and a dielectric ceramic having a negative relative dielectric constant temperature change characteristic. In addition, a composite material for a dielectric electromotive force antenna is disclosed in which a polymer material is mixed so that the temperature change of the relative dielectric constant is ± 50 ppm / ° C. or less.
JP 2001-181027 A JP-A-4-161461

  By the way, as characteristics required for the composite dielectric material, in addition to a high relative dielectric constant εr, a high Q value as an index of loss, a low temperature coefficient, and the like can be mentioned. And in order to implement | achieve the further performance improvement of a circuit board or an electronic component, it is necessary for the composite dielectric material to be used to satisfy | fill all these characteristics.

  From this point of view, for example, it is difficult to obtain a high Q value while realizing a high relative dielectric constant εr, and it is a fact that one of the characteristics must be sacrificed. For example, in the invention described in Patent Document 1, a certain degree of relative dielectric constant εr is obtained, but the Q value has not been studied. In the invention described in Patent Document 2, the temperature coefficient is emphasized, and the relative dielectric constant εr is 10 or less in any sample. The Q value has not been studied.

  Moreover, in the composite dielectric material, it is necessary to increase the relative dielectric constant εr as much as possible, but even if ceramic powder having a high relative dielectric constant εr is used, this is not always reflected. Absent. In consideration of the characteristics of the organic polymer material to be composited, an optimal combination with ceramic powder is required. However, in the dielectric ceramics conventionally used for this type of composite dielectric material, In fact, in the combination of the above, the compatibility of the characteristics is not realized.

  The present invention has been proposed in view of the above circumstances. That is, the present invention can sufficiently reflect the high relative dielectric constant εr of the dielectric ceramics, achieves an unprecedented high relative dielectric constant εr, and has a low temperature change rate of the relative dielectric constant εr. In addition, an object is to provide a novel composite dielectric material having a high Q value. In addition, the present invention utilizes the improvement in characteristics of the composite dielectric material, for example, a prepreg, a metal foil coated product, a molded body, and a composite dielectric that can improve performance when used for a circuit board, for example. An object is to provide a body substrate and a multilayer substrate.

  The present inventors have conducted intensive research for a long time in order to solve the above-mentioned problems. As a result, by using an oxide containing silver (Ag), niobium (Nb), and tantalum (Ta) as a dielectric ceramic combined with an organic polymer material in a composite dielectric material, the oxide has excellent properties. As a result, the inventors have been able to obtain the knowledge that a high dielectric constant and a high Q value that have never been realized can be realized.

The present invention has been completed on the basis of such knowledge, and is a composite dielectric material containing a dielectric ceramic and an organic polymer material. As the dielectric ceramic, the general formula Ag (Nb _{1 -x} Ta _{x) O 3} (where, characterized in that it contains 0.10 ≦ x ≦ 0.45.) temperature coefficient of variation has relative permittivity of the composition represented by the positive matrix oxide And

  In the present invention, the dielectric ceramic used has a great feature, and an oxide (silver niobium tantalate) having a composition represented by the above general formula is used. This oxide is a material composition system capable of realizing a very high relative dielectric constant εr in a high frequency region (particularly in a microwave region) by adjusting the ratio of Nb and Ta. In addition, when combined with an organic polymer material, the high relative dielectric constant εr of the oxide is sufficiently reflected, and a low loss (high Q) is also exhibited.

  On the other hand, the oxide is a rare material system in which the temperature change coefficient of the relative dielectric constant εr becomes a positive value by selecting the ratio of Nb and Ta. Usually, organic polymer materials combined with dielectric ceramics have a negative temperature change coefficient of relative dielectric constant εr, and when combined with dielectric ceramics having a negative temperature change coefficient, the temperature change rate tends to increase. In combination with the oxide having the positive temperature change coefficient, the temperature change coefficients cancel each other, and the temperature change coefficient of the entire composite dielectric material is suppressed to a small value.

  Therefore, by using the oxide as a dielectric ceramic and combining it with an organic polymer material to form a composite dielectric material, an unprecedented high dielectric constant εr can be realized and a high Q can be achieved. Further, the temperature change rate of the relative dielectric constant εr is also suppressed to a small value.

  By the way, this oxide itself is a material disclosed as a dielectric ceramic material in, for example, Japanese Patent Application Publication No. 2004-507432 and Japanese Patent Application Publication No. 2004-507433, and Japanese Patent Application Publication No. 2004-508672 and Japanese Patent Application Publication No. 2004. Various devices (microwave devices and the like) using this dielectric ceramic material are also disclosed in Japanese Patent No. 508704 and Japanese Patent Publication No. 2004-522320. However, all of the techniques described in these publicly known documents use a ceramic sintered body manufacturing process, and a technique for producing a bulk sintered body by densifying ceramic powder by firing at a high temperature. It has become.

  In order to obtain a bulk sintered body, as described above, it is necessary to make the composition into a desired crystal phase by firing at a high temperature, and at the same time, sufficiently cause a sintering reaction to become dense. However, in the production of ceramics composed of silver niobium tantalate having the above composition, it is a major problem in production that Ag having a high vapor pressure evaporates during the firing process. This evaporation of Ag changes the composition of the ceramics, causing a decrease in the density of the sintered body and a deterioration in dielectric properties.

As a method for suppressing the evaporation of Ag, it is also proposed to add a sintering aid in order to sinter at a temperature as low as possible, as described in the above-mentioned publications. For example, each of the above publications discloses using H ₃ BO ₃ or V ₂ O ₅ as a sintering aid. However, in general, in high frequency dielectric materials, impurities, lattice defects, existence of grain boundaries, etc. are the factors that increase loss. Therefore, high-purity raw materials are used in the development of high frequency dielectric materials. It is a guideline that other elemental components are not included in the crystal phase, and that another phase having a composition significantly different from the crystal phase is not present in the grain boundary region.

Therefore, the silver niobium tantalate has not been fully utilized when considering its use as a bulk sintered body, and it must be said that the material is still under development. The present invention relates to the original dielectric of an oxide (silver niobium tantalate) represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.90). As one method for exhibiting the characteristics, the present invention proposes application to a composite dielectric material configured with an organic polymer material having a low dielectric loss, which has great significance in this respect.

  Further, regarding the temperature change coefficient of the relative dielectric constant εr of the silver niobium tantalate, the temperature change coefficient of the relative dielectric constant εr of the silver niobium tantalate is too large, so that it was considered to be used as a bulk sintered body. In some cases, it is difficult to use a dielectric material having a single composition because its characteristics vary greatly with temperature. Therefore, as seen in, for example, JP-T-2004-507432, JP-T-2004-508672, JP-T-2004-508704, etc., the composition having a positive temperature change coefficient and a negative composition It has been proposed to be used as a mixed crystal form.

  However, in order to control the temperature change coefficient, a bulk sintered body in a mixed crystal state in which a crystal phase having a relative positive dielectric constant εr having a temperature change coefficient of “positive” and a crystal phase having a “negative” uniformly exists is produced. It is extremely difficult to do. This is because the crystal phase having the temperature change coefficient of “positive” and the “negative” crystal phase react with each other during sintering, and a bulk sintered body can be stably obtained while maintaining each as a separate phase. Because it is difficult.

For example, in the invention described in claim 3 of the present invention, Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramics whose temperature change coefficient of relative permittivity εr is “positive” and Ag (Nb) which is “negative”. _1-x Ta _x ) O ₃ dielectric ceramics are combined, but in the composite dielectric material of the present invention, dielectric ceramic powders of “positive” crystal phase and “negative” crystal phase are prepared separately. Since it is mixed with an organic polymer material and molded at a temperature of about 200 ° C., the crystal phases of both do not react with each other. Therefore, the composite dielectric material of the present invention can exhibit the characteristics of each crystal phase, and this point is also greatly different from the prior art disclosed in the above publication.

According to the present invention, since baking at a high temperature is not necessary, an oxide represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45). In this case, the dielectric properties are not deteriorated by evaporation of Ag or addition of a sintering aid. Therefore, it is possible to sufficiently reflect the excellent dielectric properties of the oxide, particularly the extremely high relative dielectric constant εr, and the composite dielectric having a high relative dielectric constant εr and a high Q value that has never been achieved before. It is possible to provide body material.

  Furthermore, in the present invention, a combination of an oxide having a relative dielectric constant εr having a temperature change coefficient of “positive” and an organic polymer material having a negative temperature change coefficient, or the temperature change coefficient being “ By combining an oxide that is “positive”, an oxide that is “negative”, and an organic polymer material, the temperature change coefficient of the entire composite dielectric material can be controlled. Therefore, for example, by making the value of the temperature change coefficient close to zero, it is possible to realize a composite dielectric material having a very small temperature change rate of the relative dielectric constant εr.

  Hereinafter, the composite dielectric material according to the present invention will be described in detail.

  The composite dielectric material of the present invention is a composite of dielectric ceramics and an organic polymer material (resin). Here, first, examples of the organic polymer material combined with the dielectric ceramic include thermoplastic resins and thermosetting resins. Any resin may be selected from these resins depending on the desired properties. For example, as the thermoplastic resin, polypropylene resin, polystyrene resin, polyetherimide resin, polyethersulfone resin, Examples thereof include polyacetal resins, cyclopentadiene resins, liquid crystal polymers, and mixtures thereof. The thermoplastic resin is a resin group having a relatively low loss (high Q) in a high frequency range.

  Examples of thermosetting resins include phenol resins, epoxy resins, unsaturated polyester resins, vinyl ester resins, polyimide resins, maleimide resins, polyphenol polycyanate resins, vinyl benzyl resins, and mixtures thereof. Can be mentioned. These resins are also a resin group having a relatively low loss (high Q) in a high frequency range, but when a thermosetting resin is used, a composite dielectric material having excellent heat resistance in a soldering process or the like is obtained. In particular, a vinyl benzyl resin such as a polyvinyl benzyl ether compound is a material having a dielectric property that does not depend on temperature and hygroscopicity and excellent heat resistance. In addition, when hardening a thermosetting resin, you may make a hardening | curing agent exist, for example, well-known radical polymerization initiators, such as a benzoyl peroxide, a methyl ethyl ketone peroxide, a dicumyl peroxide, can be used.

On the other hand, the dielectric ceramic has a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45) and has a relative dielectric constant εr. A dielectric ceramic powder containing an oxide having a positive temperature change coefficient is used.

Oxide having a composition represented by the general formula _{Ag (Nb 1-x Ta x} ) O 3 has a AgNbO ₃ showing ferroelectricity, a solid solution of AgTaO ₃ showing a paraelectric, for Nb and Ta By changing the ratio, this is a material system that can arbitrarily change dielectric properties such as relative permittivity εr and Q. For example, AgNbO ₃ alone (x = 0 in the above general formula) does not contain Ta, and thus does not exhibit paraelectric properties that contribute to low loss (high Q) at high frequencies, and thus a high frequency composite dielectric material. Not suitable for. On the other hand, since AgTaO ₃ alone (x = 1 in the above general formula) does not contain Nb, it does not exhibit ferroelectricity exhibiting a high relative dielectric constant εr, and even when combined with an organic polymer material. It is not a composite dielectric material exhibiting a high relative dielectric constant εr.

In the oxide, the temperature change coefficient of the relative dielectric constant εr changes from positive to negative depending on the ratio of Nb and Ta, and the temperature change coefficient itself is large. In general, low-loss organic polymer materials for high frequency use are mostly materials having a negative dielectric constant εr temperature change coefficient. For example, among the aforementioned organic polymer materials, the vinyl benzyl resin has a temperature change coefficient of The temperature change coefficient of the polyphenylene ether resin is −92 ppm / ° C., and the temperature change coefficient of the polyolefin resin is −151 ppm / ° C. Therefore, in order to adjust the temperature change coefficient of the composite dielectric material, it is necessary to include dielectric ceramics having a positive temperature change coefficient. Therefore, in the present invention, as described above, it has a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45) and has a dielectric constant. An oxide having a positive temperature change coefficient of the rate εr is used as the dielectric ceramic.

Among various dielectric ceramic materials, there are limited materials that exhibit a low loss (high Q) in the high frequency range, a relative dielectric constant εr ≧ 200, and a temperature change coefficient τε> 0. For example, a BaO—SmO ₃ —Bi ₂ O ₃ —TiO ₂ based material has a temperature change coefficient τε = −28 to +34 ppm / ° C. and a composition having a positive temperature change coefficient, but a relative dielectric constant εr of 66 It is about ~ 108. The lead zirconate-based material also has a temperature change coefficient τε of +2000 ppm / ° C., but a relative dielectric constant εr of about 120. The CaO—BaO—TiO ₂ -based material has a positive temperature change coefficient τε = + 1,630 ppm / ° C. and a relative dielectric constant εr as high as 209. However, when a composite dielectric material is used, the temperature change coefficient τε = A negative value of −240 ppm / ° C. is shown.

On the other hand, the oxide represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ has a temperature change coefficient τε changed by changing the Ta ratio x as shown in Table 1, and 0 10 ≦ x ≦ 0.45 indicates a positive temperature change coefficient τε, and the relative dielectric constant εr is 200 or more.

In the present invention, an oxide having the above composition and a positive temperature change coefficient τε is combined with an organic polymer material to cancel the temperature change coefficient, and the temperature change coefficient of the entire composite dielectric material is close to zero. Or a positive value. In this case, the temperature change coefficient can be controlled more precisely by combining an oxide having a negative temperature change coefficient of the relative dielectric constant εr. In this case, the oxide to be combined has a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.60 ≦ x ≦ 0.90) and has a relative dielectric constant temperature. This is an oxide having a negative change coefficient. In addition, Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramics having a negative temperature change coefficient τε have a higher Q value than those having a positive temperature change coefficient τε. Not only can the temperature change coefficient be controlled, but also the Q value can be improved.

  It is difficult to stably produce a dense bulk sintered body while maintaining the existence of crystal phases with different temperature change coefficients. However, in the method of compounding with organic polymer materials, each composition phase is prepared in advance. Then, since the dielectric material is molded at a low temperature of about 200 ° C. by mixing with the organic polymer material, the positive and negative composition phases do not react and the characteristics of the respective composition phases are exhibited.

By the way, the oxide is a material having a very high dielectric constant εr, but it is a big problem that Ag having a high vapor pressure evaporates during the firing process. According to the study by the present inventors, the relative density of the bulk sintered body obtained by firing at a high temperature is obtained as the crystal phase of the Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramic powder. The result of changing as shown in Table 2 depending on the firing temperature was obtained.

Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramic powder exhibits a dielectric property in a perovskite structure, but as shown in Table 1, a perovskite structure showing a dielectric property at a temperature of 600 ° C. or higher is generated. Have confirmed. FIG. 1 also shows X-rays of heterogeneous phase formation in the Ag (Nb _0.5 Ta _0.5 ) O ₃ composition where x = 0.5 in the Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramic powder. Although it is a diffraction example, as shown to Fig.1 (a), the heterogeneous phase has appeared at the temperature of 1150 degreeC or more. As shown in FIG. 1B, the appearance of a heterogeneous phase is hardly observed at a heat treatment temperature of 1100 ° C. When used as a bulk sintered body, a temperature of 1150 ° C. or higher is necessary to make it dense, but at this temperature, a heterogeneous phase is generated and the dielectric properties deteriorate.

Accordingly, in the present invention, it is preferable to use an oxide heat treatment was carried out in perovskite generation out of phase temperatures generated 1100 ° C. or less of suppressing the time of manufacturing, Ag prepared in this manner (Nb _1-x Ta _x It can be said that it is preferable to produce a composite dielectric material by combining O ₃ dielectric ceramic powder with an organic polymer material. More preferably, an oxide that has been heat-treated at 600 ° C. to 1100 ° C. is used.

_{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder to be used is, dielectric properties, and particularly preferably as high as possible relative dielectric constant εr in a high frequency region (e.g. the microwave field). Specifically, the dielectric constant εr in the microwave region of the dielectric ceramic powder is preferably 200 or more, and more preferably 300 or more. Thereby, the relative dielectric constant εr in the microwave region of the composite dielectric material can be set to 12 or more.

As for the particle diameter of the _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder to be used is not particularly limited, considering the mixing of the organic polymer material, it is preferable to properly select. For example, if the particle size of the dielectric ceramic powder used is too small, kneading with the organic polymer material may be difficult. Conversely, if the particle size of the dielectric ceramic powder becomes too large, the mixed state with the organic polymer material becomes non-uniform and the dielectric characteristics may become non-uniform. Further, when the content of the dielectric ceramic powder is large, there is a possibility that a dense composite dielectric material cannot be obtained. In view of these matters, the average particle diameter of the _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder is, 0.2 [mu] m or more, it is preferable to 100μm or less.

  The composite dielectric material of the present invention can be obtained by mixing the above dielectric ceramic powder and an organic polymer material (resin). At this time, the mixing ratio of the dielectric ceramic powder can be arbitrarily set, but is preferably 20% by volume or more and less than 70% by volume. The mixing ratio of the organic polymer material is 30% by volume or more and less than 80% by volume. If the ratio of the dielectric ceramic powder is less than 20% by volume, the effect of containing the oxide having a high relative dielectric constant εr may not be sufficiently exhibited. On the contrary, when the ratio of the dielectric ceramic powder is 70% by volume or more, the denseness of the obtained composite dielectric material is deteriorated, and for example, there is a possibility that problems such as easy penetration of moisture and deterioration of dielectric characteristics may occur. There is.

Further, when mixing the dielectric ceramic powder and the organic polymer material, it is preferable to set the blending in consideration of the relative dielectric constant εr of the finally obtained composite dielectric material. Specifically, the compounding ratio is preferably adjusted so that the relative dielectric constant εr in the microwave region of the composite dielectric material is 12 or more, and the ratio of the dielectric ceramic powder is 40% by volume or more and 70% by volume. More preferably, it is less than%. Thereby, it is possible to sufficiently exhibit the dielectric characteristics of the Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramic powder and realize a composite dielectric material having a very high relative dielectric constant εr.

Furthermore, when mixing the dielectric ceramic powder and the organic polymer material, it is preferable to determine the formulation in consideration of the temperature change coefficient τε of the relative dielectric constant εr of the entire composite dielectric material. For example, it has a composition represented by the general formula Ag (Nb _1−x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45), and the temperature change coefficient τε of the relative dielectric constant εr is positive. When the composite dielectric material is formed by combining the oxide and the organic polymer material, the temperature change coefficient τε of the relative dielectric constant εr of the entire composite dielectric material is changed to a positive value by changing the mixing ratio of these. be able to.

It has a composition represented by the general formula Ag (Nb _1−x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45), and the temperature change coefficient τε of the relative dielectric constant εr is positive. An oxide and a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.60 ≦ x ≦ 0.90) and a temperature change coefficient τε of relative permittivity εr In the case of using an oxide having a negative value and combining these with an organic polymer material to form a composite dielectric material, the relative dielectric constant εr of the entire composite dielectric material can be reduced by changing the compounding ratio thereof. The temperature change coefficient τε can be controlled more precisely, and the temperature change coefficient τε can be brought close to zero. Therefore, for example, by changing the blending ratio, the temperature change rate of the relative dielectric constant of the entire composite dielectric material is ± 2% in the temperature range of −30 ° C. to + 85 ° C. with reference to the relative dielectric constant of + 20 ° C. Is preferable (corresponding to | τε | ≦ 348 ppm / ° C.). Furthermore, it is preferable to control the blending ratio so that the temperature change rate is within ± 1% (corresponding to | τε | ≦ 174 ppm / ° C.). Moreover, the combined use with an oxide having a negative dielectric constant εr and a temperature change coefficient τε improves the Q value of the composite dielectric material.

  Unlike the bulk sintered body made only of dielectric ceramics, the composite dielectric material of the present invention is configured by compositing dielectric ceramic powder with an organic polymer material. Therefore, the specific gravity can be reduced and the weight of the material can be reduced. Further, since the composite dielectric material can be produced at a low temperature of about 200 ° C., shrinkage or deformation caused by firing at a high temperature is not observed, and deterioration of the characteristics of the internal conductor made of, for example, silver or copper can be prevented.

  The composite dielectric material having the above configuration can be used for, for example, a circuit board, a prepreg for a circuit board, various electronic components, and the like. For example, when used for a circuit board, a high-frequency circuit board is constructed by using the composite dielectric material for a so-called base board, forming a wiring pattern thereon, and mounting necessary components. Can do. Further, a multilayer substrate can be formed by laminating a plurality of layers of substrates made of the composite dielectric material. For example, a high-performance multilayer substrate can be constructed by using the composite dielectric material as a prepreg and laminating a substrate made of the composite dielectric material through the prepreg.

  Hereinafter, a prepreg, a metal foil coated product, a molded product, and a composite dielectric substrate and a multilayer substrate using these will be described as usage forms of the composite dielectric material of the present invention.

  First, a preferred method for producing a prepreg will be described. In order to produce a prepreg, for example, a polyvinyl benzyl ether compound is used as an organic polymer material, and a 40 to 60% solution is prepared in terms of mass percentage. The solvent used at this time is preferably a volatile solvent such as toluene, xylene or methyl ethyl ketone. Thereafter, the dielectric ceramic powder is added and mixed with a mixing stirrer. Mixing can also be performed with a ball mill or the like. Finally, a volatile solvent such as toluene is added to adjust the viscosity, and the mixture is stirred with a mixing stirrer for 10 to 20 minutes. At this time, it is desirable to stir while degassing. Thereby, a composite dielectric substrate material composition solution (slurry) can be obtained.

The composite dielectric material composition solution (slurry) thus obtained is applied to a cloth substrate such as a glass cloth. In particular, it is preferable to use a glass cloth as the cloth substrate. A glass cloth having a cloth mass of 40 g / m ² or less and a thickness of 50 μm or less (for example, trade name Asahi Schwer, etc.) is preferable for improving the filling rate of the dielectric ceramic powder. Although there is no restriction | limiting in particular in the minimum of cloth mass and the minimum of thickness, They are about 25 g / m < ² > and 30 micrometers, respectively.

  As the glass cloth, an E glass cloth, a D glass cloth, an H glass cloth, or the like can be properly used according to electrical characteristics. Further, for the purpose of improving interlayer adhesion, etc., a coupling treatment or the like may be performed on the glass cloth. In addition to the glass cloth, the cloth base material may be a reinforcing material using a nonwoven fabric such as aramid or polyester woven from yarn. In this case, the thickness or the like may be the same as that of the glass cloth.

  As the coating thickness at the time of the coating, it is practically preferable to set the thickness after the B-stage to 50 to 200 μm, but it is possible to select the coating timely according to the plate thickness and filler content. . Further, the coating method may be any known method such as a method of applying a predetermined thickness with a vertical coating machine, a method of applying to a cloth substrate by a doctor blade coating method, etc. A production method can be selected according to the method. For this reason, productivity is high. A film formed by such a method is heat-treated at 100 to 120 ° C. for 0.5 to 3 hours to obtain a prepreg (B stage). The conditions at this time may be selected in a timely manner according to the resin contest, desired fluidity, and the like.

The case where a prepreg obtained here is used to produce a double-sided copper foil substrate, for example, will be described. The prepreg is stacked so as to have a predetermined thickness, and both sides of the laminate are sandwiched between copper foils and molded. The forming method is performed by a known method such as hot pressing. The molding conditions are preferably 100 to 200 ° C., 9.8 × 10 ^{5 to} 7.8 × 10 ⁶ Pa, 0.5 to 10 hours, and may be step-cured as necessary.

  The metal foil used at this time is generally copper, but is not limited thereto, and can be selected from gold, silver, aluminum, and the like. In addition, it is preferable to use an electrolytic foil when securing peel strength, and using a rolled foil with less skin effect due to surface irregularities when emphasizing high-frequency characteristics. The thickness of the metal foil is 8 to 70 μm, and a metal foil having an appropriate thickness may be selected and used according to the application and required characteristics (pattern width and accuracy, DC resistance, etc.).

  In addition, the above-mentioned composite dielectric material composition solution may be coated on a metal foil such as a copper foil as described above by a doctor blade coating method or the like and dried to obtain a metal foil coated product. A composite dielectric substrate may be produced. The coating thickness in this case may be the same as that of the prepreg. Drying may be performed at 100 to 120 ° C. for about 0.5 to 3 hours.

Moreover, when producing a plate-shaped molded object by press molding, although the mixing method etc. are the same as the method mentioned above, the mixed slurry is dried at 90-120 degreeC, and the lump of a mixture is produced. Furthermore, this lump is pulverized by a mortar or a known method to obtain a mixed powder. This mixed powder is press-molded in a mold at 100 to 150 ° C., 9.8 × 10 ^{5 to} 7.8 × 10 ⁶ Pa, for 0.1 to 3 hours to obtain a plate-shaped molded body. The thickness of the plate-shaped molded body is preferably 0.05 to 5 mm, and is appropriately selected according to the desired plate thickness and dielectric ceramic powder content. The molded body is cured at 100 to 200 ° C., 9.8 × 10 ^{5 to} 7.8 × 10 ⁶ Pa, for 0.5 to 10 hours. Further, step cure may be performed as necessary.

A composite made by appropriately combining the prepreg produced as described above, a metal foil coated product such as copper foil, a plate-shaped molded body, a metal foil such as copper foil, and a cloth base material such as glass cloth. A dielectric substrate is produced. The molding conditions are 100 to 200 ° C., 9.8 × 10 ^{5 to} 7.8 × 10 ⁶ Pa, and 30 to 120 minutes. Alternatively, the prepreg, metal foil coated product, molded product, metal foil such as copper foil, cloth base material such as glass cloth, etc., and composite dielectric substrate produced by these, etc. are used as laminated elements, and in multiple layers It is also possible to construct a multilayer substrate by stacking layers.

  In addition to the above, the composite dielectric material of the present invention can be used for various electronic components such as multilayer capacitors, resonators, inductors, and antennas. For example, in the case of a resonator, a strip line, a ground plane, an external conductor, an internal conductor, or the like may be formed between the surface of the laminate made of the composite dielectric material or between the laminates, and the necessary portions may be electrically connected. . The resonator using the composite dielectric material of the present invention is used in various filters such as a high-pass filter, a low-pass filter, a band-pass filter, a band elimination filter, a demultiplexing filter, a diplexer, a voltage-controlled oscillator, etc. that combine these filters. Application is possible. When the composite dielectric material of the present invention is used for these electronic components, the temperature change coefficient τε of the relative dielectric constant εr is adjusted according to the usage environment by adjusting the mixing ratio of the dielectric ceramics and the organic polymer material. It is also possible to control.

  Hereinafter, specific examples to which the present invention is applied will be described based on experimental results.

Ag in _{(Nb 1-x Ta x)} O 3 dielectric ceramic powder of the produced general formula _{Ag (Nb 1-x Ta x} ) O 3, as the value of x becomes a desired value, _Ag 2 O (purity Chemical laboratory, purity 99%), Nb ₂ O ₅ (high purity chemical laboratory, purity 99.9%), Ta ₂ O ₅ (high purity chemical laboratory, purity 99.9%) The powder was weighed and mixed for 16 hours in ethanol using a ball mill. After drying this, the obtained raw material mixed powder was heat-treated at 1000 ° C. to 1100 ° C. for 10 hours in an oxygen atmosphere to produce an Ag (Nb _1-x Ta _x ) O ₃ phase. _The generation confirmation of _{Ag (Nb 1-x Ta x} ) O 3 phase was performed using an X-ray diffractometer (manufactured by Rigaku Corporation, trade name RINT2500).

After the pulverized particle径調clause in ethanol using a ball mill again, to obtain a powdery _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramics used dried to produce a composite dielectric material It was. The average particle size of the dielectric ceramic was measured using a laser diffraction particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., trade name: MICROTRAC HRA model: 9320-X100). The average particle diameter was 2.5 μm to 3.6 μm.

The manufacturing Ag composite dielectric material _{(Nb 1-x Ta x)} O 3 dielectric ceramic powder and an organic polymer material ratio by volume of (polyvinyl benzyl ether compound) is given (dielectric ceramic powder 40 vol%) as described above, it was weighed and polyvinyl benzyl ether compound _Ag previously prepared _{(Nb 1-x Ta x)} O 3 dielectric ceramics (average particle diameter 2.5Myuemu～3.6Myuemu), were thoroughly mixed in toluene. This was dried at 110 ° C. and then pulverized to obtain a mixed powder of Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramics and a polyvinyl benzyl ether compound. This powder was put into a mold and pressed at 150 ° C. with a press pressure of 4.0 × 10 ⁶ Pa, and then thermally cured at 200 ° C. to produce a substrate-like composite dielectric. Then, a rod-like sample (1 mm × 1 mm × 9 mm) was cut out and used as a measurement sample.

For each of the samples prepared for evaluation , the relative permittivity εr and Q at 2 GHz were set to a temperature of 20 according to the cavity resonator perturbation method (measurement device used: Hewlett-Packard, trade names 83620A and 8757C, and thermostatic chamber Desatch 900 series). Measured at ° C. Further, the relative dielectric constant εr was measured in the temperature range of −30 ° C. to + 85 ° C., and the temperature change coefficient τε was obtained. The temperature change coefficient τε is a relative dielectric constant at a temperature of + 20 ° C., where εr ₁ and εr ₂ are relative dielectric constants of the composite dielectric material at the lowest temperature T ₁ ° C and the highest temperature T ₂ ° C in the temperature range. Where εr ₊₂₀ is a value defined by Equation 1 below.

Study on Composite Dielectric Material Combining Ag (Nb _1-x Ta _x ) O ₃ Dielectric Ceramic Powder (Temperature Change Coefficient τε of Dielectric Constant εr is Positive) and Organic Polymer Material Ag (Nb ₀ Samples 1 to 4 were prepared using _.75 Ta _0.25 ) O ₃ powder (average particle size 2.5 μm) and changing the ratio. Ag (Nb _0.75 Ta _0.25 ) O ₃ powder is heat-treated in an oxygen atmosphere at a temperature of 1000 ° C., and the relative dielectric constant εr at a temperature of 20 ° C. is 455, Q × f = 294 GHz, relative dielectric constant. The temperature change coefficient τε (−30 ° C. to + 85 ° C.) of the rate εr is +2430 ppm / ° C. About each produced sample, the characteristic was evaluated in the way described in the term of the said evaluation. The results are shown in Table 3.

As is apparent from Table 3, by using Ag (Nb _0.75 Ta _0.25 ) O ₃ powder, the temperature change coefficient τε of the entire composite dielectric material becomes a positive value and can be suppressed to a small value. I understand. Further, by setting the ratio of the dielectric ceramic powder to 40% by volume or more, the relative dielectric constant εr of the composite dielectric material is a value of 12 or more.

With _{Ag (Nb 1-x Ta x} ) O 3 Ag (Nb 1-x Ta x) O 3 dielectric ceramic powder having the composition shown in Table 1 of the study destination on Temperature change coefficient τε of the dielectric ceramic powder, the composite Dielectric materials were prepared (Sample 5 to Sample 15). _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder, the temperature 1000 ° C. C. to 1100 ° C., is obtained by heat treatment in an oxygen atmosphere, the average particle size is 2.5Myuemu～3.6Myuemu. For comparison, a composite dielectric material using TiO ₂ as a dielectric ceramic (sample 16), a composite dielectric material using CaTiO ₃ (sample 17), Bi ₂ O ₃ —BaO—Nd ₂ O ₃ — A composite dielectric material (sample 18) using a TiO ₂ -based material and a composite dielectric material (sample 19) using a CaO-BaO-TiO ₂ -based material, in which the temperature change coefficient τε is positive for dielectric ceramics alone, are shown. It produced similarly. About each produced sample, the characteristic was evaluated in the way described in the term of the said evaluation. The results are shown in Table 4.

As is clear from Table 4, by using a dielectric ceramic powder having a composition represented by Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45). The temperature change coefficient τε of the entire composite dielectric material is also a positive and small value. In contrast, the composite dielectric material (sample 19) using the CaO—BaO—TiO 2 -based material had a negative temperature change coefficient, whereas the dielectric ceramic (single) had a positive temperature change coefficient τε. It became. In samples 1 to 15 using dielectric ceramic powder having a composition represented by Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45), Compared with the case where other dielectric materials are used (sample 16 to sample 19), the value of relative dielectric constant εr is also large.

As Study dielectric ceramic powder temperature change coefficient τε is relates to the combination of positive and negative _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic _{powder, Ag (Nb 0.65 Ta 0.35)} O 3 powder (x = 0 .35, average particle diameter 3.2 μm) (A) and Ag (Nb _0.35 Ta _0.65 ) O ₃ powder (x = 0.65, average particle diameter 2.9 μm) (B) Samples 20 to 23 were prepared at different ratios. These dielectric ceramic powders were heat-treated in an oxygen atmosphere at a temperature of 1050 ° C.

For these samples, the relative dielectric constant εr at temperatures of −30 ° C., + 20 ° C., and + 85 ° C. was measured, and the rate of change (Δεr / εr) was calculated based on the relative dielectric constant εr at 20 ° C. The change rate (Δεr / εr) of the relative dielectric constant εr was calculated by the following equation 2 where the relative dielectric constant at a temperature of 20 ° C. was εr ₊₂₀ and the relative dielectric constant at a temperature T ° C. was εr _T. The results are shown in Table 5. In addition, FIG. 2 shows the change rate of the relative dielectric constant εr in each sample.

Table evident from 5 or FIG. 2, the temperature change coefficient τε positive _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder and a negative _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder , The change in temperature of the relative dielectric constant εr of the entire composite dielectric material can be reduced. For example, the rate of change (Δεr / εr) can be ± 2% or less, and further ± 1% or less. . Also, Q by the combined high temperature change coefficient τε negative _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder, which can also be performed to improve the Q value.

Dielectric ceramic powder, Ag (Nb _0.65 Ta _0.35 ) O ₃ powder (x = 0.35, used in the example of the preparation destination of the cross base coating prepreg and the composite dielectric substrate using the same . Average particle size 3.2 μm) (A) and Ag (Nb _0.35 Ta _0.65 ) O ₃ powder (x = 0.65, average particle size 2.9 μm) (B) and organic polymer material (polyvinylbenzyl) The ether compound) was thoroughly mixed in toluene so that the volume ratio was a predetermined ratio. This slurry was applied to a glass cloth (manufactured by Asahi Schwer) having a cloth mass of 40 g / m ² and a thickness of 50 μm with a coating machine, dried at 110 ° C., and then used as a prepreg. The thickness of this prepreg was 170 μm.

Next, 10 prepared prepregs were stacked and pressed at 150 ° C. with a press pressure of 4.0 × 10 ⁶ Pa, followed by thermosetting at 200 ° C. to prepare a composite dielectric substrate having a thickness of 1.5 mm. . Then, a rod-shaped sample (1.5 mm × 1.5 mm × 9 mm) was cut out and used as a measurement sample (sample 24 to sample 27: equivalent to the example).

For these samples, the relative dielectric constant εr at temperatures of −30 ° C., + 20 ° C., and + 85 ° C. was measured, and the rate of change (Δεr / εr) was calculated based on the relative dielectric constant εr at 20 ° C. The results are shown in Table 6. Even in a composite dielectric substrate manufactured using a prepreg, the temperature change of the relative permittivity εr is suppressed by combining Ag (Nb _1-x Ta _x ) O ₃ dielectric ceramic powders with positive and negative temperature change coefficients τε. It has been.

It is an X-ray diffraction chart in Ag (Nb _0.5 Ta _0.5 ) O ₃ composition, (a) is an X-ray diffraction chart when heat-treated at 1150 ° C., and (b) is an X-ray diffraction chart when heat-treated at 1100 ° C. It is a line diffraction chart Temperature change coefficient τε positive _{Ag (Nb 1-x Ta x} ) O 3 dielectric ceramic powder and a negative _{Ag (Nb 1-x Ta x} ) O 3 in the dielectric constant εr of combining the dielectric ceramic powder It is a characteristic view which shows a change rate.

Claims (34)

A composite dielectric material containing a dielectric ceramic and an organic polymer material,
The dielectric ceramic has a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.10 ≦ x ≦ 0.45) and has a temperature change coefficient of relative permittivity. A composite dielectric material comprising an oxide in which is positive.   2. The composite according to claim 1, wherein the dielectric ceramic and the organic polymer material are blended in such a blend ratio that the temperature change coefficient of the relative permittivity of the entire composite dielectric material becomes a positive value. Dielectric material. The dielectric ceramic further has a composition represented by the general formula Ag (Nb _1-x Ta _x ) O ₃ (where 0.60 ≦ x ≦ 0.90) and has a temperature change coefficient of relative permittivity. The composite dielectric material according to claim 1, comprising an oxide in which is negative.   The compounding ratio of the two kinds of oxides and organic polymer materials is set so that the temperature change coefficient of the relative dielectric constant of the entire composite dielectric material becomes a predetermined value. Composite dielectric material.   The temperature change rate of the relative dielectric constant of the entire composite dielectric material is set within ± 2% in a temperature range of -30 ° C to + 85 ° C with reference to a relative dielectric constant of + 20 ° C. 3. The composite dielectric material according to 3 or 4.   6. The composite dielectric material according to claim 5, wherein the rate of temperature change is within ± 1%.   7. The composite dielectric material according to claim 1, wherein a relative dielectric constant εr in a high frequency band of 500 MHz or more is 12 or more.   8. The composite dielectric material according to claim 1, wherein a ratio of the dielectric ceramic is 20 volume% or more and less than 70 volume%.   The composite dielectric material according to claim 1, wherein the oxide is heat-treated at a temperature of 1100 ° C. or less.   10. The composite dielectric material according to claim 1, wherein a relative dielectric constant εr of the oxide in a high frequency band of 500 MHz or higher is 200 or higher.   11. The composite dielectric material according to claim 1, wherein an average particle diameter of the oxide is 0.2 μm or more and 100 μm or less.   The composite dielectric material according to claim 1, wherein the organic polymer material is a thermoplastic resin.   The composite dielectric material according to claim 1, wherein the organic polymer material is a thermosetting resin.   The composite dielectric material according to claim 13, wherein the thermosetting resin is a vinylbenzyl resin.   15. The composite dielectric material according to claim 14, wherein the vinyl benzyl resin is mainly composed of a polyvinyl benzyl ether compound.   A prepreg obtained by applying a slurry obtained by dispersing the composite dielectric material according to any one of claims 1 to 15 in a solvent to a cloth substrate and drying the slurry.   The prepreg according to claim 16, wherein the cloth substrate is a glass cloth. The prepreg according to claim 17, wherein the glass cloth has a cloth mass of 40 g / m ² or less and a thickness of 50 μm or less.   A metal foil coated product obtained by coating a slurry obtained by dispersing the composite dielectric material according to any one of claims 1 to 15 in a solvent on a metal foil and drying the slurry.   The metal foil coated product according to claim 19, wherein the metal foil is a copper foil.   A molded body comprising a slurry in which the composite dielectric material according to any one of claims 1 to 15 is dispersed in a solvent, which is dried and molded.   A composite dielectric substrate using the composite dielectric material according to claim 1.   The composite dielectric substrate according to claim 22, wherein the composite dielectric substrate is formed by heating and pressurizing the prepreg according to any one of claims 16 to 18.   The composite dielectric according to claim 22, wherein the composite dielectric is formed by heating and pressing the prepreg according to any one of claims 16 to 18 in a state of being sandwiched between metal foils, and having metal foils on both sides. substrate.   The composite dielectric substrate according to claim 24, wherein the metal foil is a copper foil.   The metal foil coated product according to claim 19 or 20 is bonded to both surfaces of a cloth substrate so that the coated surfaces are in contact with each other, and is formed by heating and pressing in this state, and has a metal foil on both surfaces. The composite dielectric substrate according to claim 22.   27. The composite dielectric substrate according to claim 26, wherein the cloth substrate is a glass cloth. 28. The composite dielectric substrate according to claim 27, wherein the glass cloth has a cloth mass of 40 g / m ² or less and a thickness of 50 μm or less.   The composite dielectric substrate according to claim 22, wherein the composite dielectric substrate is formed by heating and pressurizing the molded body according to claim 21.   23. The composite dielectric substrate according to claim 22, wherein the composite dielectric substrate is formed by heating and pressing the molded body according to claim 21 sandwiched between metal foils, and having metal foils on both sides.   The composite dielectric substrate according to claim 30, wherein the metal foil is a copper foil.   32. The composite dielectric substrate according to claim 22, wherein the composite dielectric substrate is used in a high frequency band of 500 MHz or more.   The prepreg according to any one of claims 16 to 18, the metal foil coated product according to claim 19 or 20, the molded body according to claim 21, and the composite dielectric according to any one of claims 22 to 31. A multilayer substrate having a multilayer structure including at least one selected from substrates as a multilayer element, the multilayer element including the multilayer element.   34. The multilayer substrate according to claim 33, which is used in a high frequency band of 500 MHz or more.

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