JP2006134869A - Dielectric composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high dielectric composition highly filled with an inorganic filler and having a low void ratio. <P>SOLUTION: This dielectric composition contains an inorganic filler and a resin. In the dielectric composition, the average particle size of the inorganic filler is 0.01-1 μm; and the surface area of the inorganic filler is 1.05-1.3 times as much as that of a perfect sphere having the same volume. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dielectric composition exhibiting characteristics suitable as a capacitor or an interlayer insulating material for a circuit material having a function as a capacitor.

  In recent years, with the demand for downsizing electronic devices, increasing the speed of signals, and increasing the capacity, the density of mounted circuit components has been increasing. However, electrical noise increases and data errors are becoming a problem. In order to suppress the generation of this electrical noise and to operate the semiconductor device stably, it is important to supply a necessary amount of current from a position close to the semiconductor device. For this purpose, it is effective to dispose a capacitor having a large capacity directly under the semiconductor device as a decoupling capacitor (decoupling capacitor).

  There is a method of arranging an external capacitor such as a chip capacitor on a printed wiring board. However, from the viewpoint of miniaturization, it is advantageous to add an inorganic filler to the inner layer of the printed wiring board to give the printed wiring board itself a capacitor function, and a composite of inorganic filler and resin is used as an interlayer insulating material. A method (see Patent Documents 1 and 2) is known.

  However, the dielectric constant of a composite obtained by mixing a conventional inorganic filler and a resin is about 10 to 40, which is low. Although the dielectric constant can be increased to some extent by increasing the inorganic filler content, if the inorganic filler content exceeds 50% by volume, the dielectric constant does not increase even if the inorganic filler content is increased. It was seen. This is considered to be due to the fact that in the high inorganic filler content region, the filling rate of the inorganic filler in the composite is less likely to increase effectively due to an increase in voids or the like. Therefore, as a method for highly filling the inorganic filler, a method of mixing two or more types of inorganic fillers (see Patent Documents 3 and 4) and a method of using the shape effect of the inorganic filler (Patent Documents 5 and 6). 7) has been proposed.

  However, in the above technique, in order to sufficiently obtain the effect of high filling, the ratio of the two types of particle sizes needs to be 5 times or more, and generally a large particle size of about 5 to 50 μm as a large particle size inorganic filler. Inorganic fillers are often used. Therefore, when the inorganic filler content is increased to improve the dielectric constant, the surface irregularities become larger, the impedance in the in-film direction becomes non-uniform, or another circuit material such as wiring is placed on the composition. However, there was a problem that workability deteriorated. In addition, in the case of the shape of the inorganic filler, when a substantially triangular shape or a substantially rectangular shape is used as a material having a large average major axis, the one having a small average major axis is filled into the gap, and the effect of improving the filling state is obtained. can get. However, in order to make the inorganic filler into a substantially triangular shape or a substantially rectangular shape, there has been a problem that variations in the shape of the inorganic filler are further increased through complicated processes such as pulverization and classification. Further, when the inorganic filler having a small particle size is 0.5 μm or less, there is a problem that the viscosity of the inorganic filler is increased during the resin kneading and it is difficult to increase the filling of the inorganic filler.

On the other hand, in order to reduce the size and thickness of the system mounted inside, development of high-density SiP (system in package) that incorporates not only memory but also LSI with a large number of terminals is being carried out at a rapid pace. However, the capacitor built in this SiP is strongly required to be thin. Furthermore, since the capacitance of the capacitor is inversely proportional to the thickness of the interlayer insulating material, it is preferable to reduce the thickness of the interlayer insulating material from the viewpoint of increasing the capacitance of the capacitor.
JP-A-5-57852 (Claims) JP-A-6-85413 (Claims) JP-A-53-88198 (Claims) JP 2001-233669 A (Claims) JP 2001-68803 A (Claims) JP 2001-233669 A (Claims) JP 2001-237507 A (Claims)

  In view of such a situation, the present invention aims to obtain a high dielectric composition having a low porosity, which is highly filled with an inorganic filler, and further, an interlayer for a large capacitance capacitor incorporated in a high-density SiP. Provided is a dielectric composition that is sufficiently thinned as an insulating material.

  That is, the present invention is a dielectric composition containing an inorganic filler and a resin, wherein the average particle size of the inorganic filler is 0.01 μm or more and 1 μm or less, and the surface area of the inorganic filler is 1.05 relative to a true sphere of the same volume. It is a dielectric composition characterized by containing the inorganic filler which is 2 times or more and 1.3 times or less.

  According to the present invention, a dielectric composition having a low porosity and a high relative dielectric constant can be easily obtained. Furthermore, a thin film having a uniform film thickness and uniform physical properties can be easily obtained. Since this is suitable for a large capacitance, it is useful for a capacitor incorporated in a high-density SiP and an interlayer insulating material for circuit board materials having a function as a capacitor.

  The dielectric composition according to the present invention includes an inorganic filler and a resin, and the inorganic filler has an average particle size of 0.01 μm to 1 μm, and the surface area of the inorganic filler is 1.05 times that of a true sphere having the same volume. It is characterized by being 1.3 times or less.

  The inorganic filler used in the present invention has a surface area of 1.05 times or more and 1.3 times or less compared to a true sphere having the same volume. Preferably they are 1.1 times or more and 1.25 times or less. (For example, the regular hexahedron is 1.25 times, and the regular tetrahedron is 1.5 times.) Since the interaction with the resin increases as the contact area increases, the surface area is less than 1.05 times. A sufficient interaction between the filler and the resin cannot be obtained. When the surface area is 1.1 times or more, re-aggregation after dispersion hardly occurs, and the dispersion stability of the paste is good. Also, the smaller the particle size, the greater the effect. In the case of an inorganic filler having a surface area larger than 1.3 times, an inorganic filler having a roughened surface, an inorganic filler having a concavo-convex portion, and an inorganic filler having no three-dimensional objectivity can be considered, but if the specific surface area becomes too large There is a tendency that voids are easily formed at the interface with the resin, the dielectric constant is lowered, and long-term reliability tends to be insufficient. On the other hand, when the surface area is 1.25 times or less, the inorganic filler-dispersed paste is less likely to agglomerate, the change in viscosity is small, and kneading, dispersion, and coating are less affected. Further, porous inorganic fillers and concave inorganic fillers are not preferable because voids are easily formed.

  Examples of the shape of the inorganic filler include a true spherical shape, a substantially spherical shape, a substantially triangular shape, a substantially rectangular shape, an elliptical spherical shape, a needle shape, a rod shape, a plate shape, and a cubic shape (dice) shape, and in particular, a hexahedral dice shape. It is preferable. In the present invention, the “hexagonal dice” is not necessarily a regular hexahedron, and is a hexahedron including a hexahedral sphere with chamfered corners and sides. However, it is preferable that each surface of the hexahedron is not a concave surface but a convex surface. A needle-like inorganic filler is not preferable because a strong force is applied when the inorganic filler is dispersed in a resin or a solvent, and the inorganic filler is crushed to impair the shape. A rod-like, plate-like, substantially rectangular, or oval-spherical inorganic filler is preferable because it does not have a three-dimensional objectivity, and when it is filled at a high density, a gap is generated between the inorganic filler and the inorganic filler, which acts as a steric hindrance Absent.

  A substantially triangular inorganic filler has a surface area approximately 1.49 times as large as a true sphere of the same volume, but if the surface area becomes too large, voids are formed at the interface with the resin when the inorganic filler is highly filled. Since it is easy to do, it is not preferable. In addition, it is difficult to obtain a substantially triangular or substantially rectangular inorganic filler having a particle size of 0.5 μm or less, and the inorganic filler having an average major axis of 5 to 50 μm is prepared by a process of pulverizing and classifying. In many cases, it is difficult to obtain a stable shape with large variations in the shape of the inorganic filler. When the inorganic filler is spherical or substantially spherical, when filled with a high density, a diamond-shaped void is formed between the inorganic filler and the inorganic filler, and no other inorganic filler can enter the void. Furthermore, the spherical or substantially spherical inorganic filler has a small surface area and a small contact area with the resin, the dispersant, and the surface treatment agent. For this reason, when the particle size of the inorganic filler is reduced, the specific surface area is reduced, the interaction with the resin through the dispersant and the surface treatment agent is not sufficiently obtained, and the inorganic filler is preferably aggregated and the resin fluidity is lowered. Absent. In particular, when an inorganic filler having a particle size of 10 nmφ or less is used, inorganic filler aggregation and resin flowability are likely to occur. As the shape of the inorganic filler, a hexahedral dice shape can be used alone, or two or more types of inorganic fillers can be mixed and used.

  In the present invention, the shape of the inorganic filler can be measured by observation with an electron microscope or an optical microscope. Further, the shape of the inorganic filler contained in the dielectric composition of the present invention is such that a transmission electron is formed with respect to an ultrathin slice obtained by forming a thin film from the dielectric composition and cutting a film cross section in the film thickness direction of the thin film. It can be measured by observation with a microscope (TEM). Since the transmittance with respect to the electron beam is different between the inorganic filler and the resin, the inorganic filler and the resin can be identified by the difference in contrast in the TEM observation image. FIG. 1 shows a cross-sectional TEM photograph of a dielectric composition thin film using an hexagonal dice-like inorganic filler.

  The magnification of the surface area of the inorganic filler with respect to the surface area of the true sphere of the same volume can be measured by the following method by measuring the specific surface area, specific gravity, and average particle size. The specific surface area of the inorganic filler can be measured by the BET method, and the specific gravity of the inorganic filler can be measured by the Archimedes method.

  In the present invention, the average particle size of the inorganic filler is measured by XMA measurement and transmission through an ultrathin section obtained by forming a dielectric composition thin film and cutting out a film cross section in the film thickness direction of the thin film. It can be measured by observation with a scanning electron microscope (TEM). Alternatively, an inorganic filler dispersed in a solvent and loosened in an aggregated state is dropped onto a TEM observation mesh, and after the solvent is evaporated, XMA measurement and transmission electron microscope (TEM) observation are performed. It can be measured. Since the transmittance with respect to the electron beam is different between the inorganic filler and the resin, the inorganic filler and the resin can be identified by the difference in contrast in the TEM observation image. When a plurality of types of inorganic fillers are used, each inorganic filler can be identified by elemental analysis based on XMA measurement and crystal structure analysis by electron diffraction image observation. The distribution of the area of the inorganic filler and resin thus obtained is obtained by image analysis, and the particle size can be calculated from the area by approximating the cross section of the inorganic filler to be circular. The particle size may be evaluated for TEM images with a magnification of 5000 times and 40000 times. The calculated particle size distribution is represented by a histogram in increments of 0.1 μm in a TEM image with a magnification of 5000 times and a histogram in 0.01 μm increments in a TEM image with a magnification of 40000 times, and the central value of the class at which the frequency becomes a maximum value. Is the average particle size. As a method for evaluating the particle size distribution, a scanning electron microscope (SEM) may be used instead of TEM in the above method.

  Other methods include dynamic light scattering, which measures the fluctuation of scattered light due to Brownian motion of inorganic fillers, and electrophoretic light scattering, which measures the Doppler effect of scattered light when inorganic fillers are electrophoresed. can do.

  In the present invention, the surface area of a true sphere having the same volume can be determined by the following method. When it is assumed that the inorganic filler is spherical, the surface area, volume, and specific surface area of the spherical inorganic filler can be calculated by the following formulas (1) to (3).

Surface area (cm ² ) S = 4πr ² (1)
Volume (cm ³ ) V = 4 / 3πr ³ (2)
Specific surface area (cm ² / g) A = S / (V · a) (3)
S: Surface area of one true sphere r: Radius of a true sphere V: Volume of one true sphere A: Specific surface area of a true sphere of radius r a: Specific gravity of an inorganic filler.

The specific surface area is the surface area per gram of the object, and is included in 1 g when it is assumed that the number of inorganic fillers contained in 1 g is a true sphere having an average particle size determined by _a dynamic light scattering method or the like. It can be considered that the number of inorganic fillers _nb is substantially equal. Therefore, by comparing the specific surface area obtained from the BET method and the specific surface area obtained by the above method when it is assumed to be a true sphere, the surface area of the inorganic filler is compared with a true sphere of the same volume. You can calculate how many times it is.

  Moreover, the volume, surface area, and average particle size of the inorganic filler when the dielectric composition is made into a thin film are observed with a transmission electron microscope (TEM) with respect to an ultrathin section obtained by cutting the film cross section in the film thickness direction of the thin film. It can also calculate by simulation (image analysis) from the cross-sectional shape of the inorganic filler. The volume, surface area, and average particle size of the inorganic filler can also be calculated from image analysis of the TEM image by observing the inorganic filler with a transmission electron microscope (TEM).

Further, as a method for extracting the inorganic filler from the thin film of the dielectric composition, the resin component can be removed from the dielectric composition by using a method such as plasma etching, temperature rise, and dissolution. The plasma etching method is a method in which plasma is generated using a reactive ion etching apparatus (RIE), and a resin component is etched by radicals or ions generated by separation of active gas. As the active gas, O ₂ (oxygen), CF ₄ (tetrafluorocarbon), or the like can be appropriately used as long as it is an active gas that does not etch the inorganic filler. The temperature raising method is a method in which only the resin component is thermally decomposed and removed by heating, but can be used when the temperature at which the resin component is thermally decomposed is a temperature at which the inorganic filler does not grow. The dissolution method is a method of removing only the resin component by dissolution, but any etching solution that dissolves only the resin component and does not react with the inorganic filler can be used as appropriate.

  The inorganic filler used in the present invention preferably has an average particle size of 0.01 μm or more and 1 μm or less. More preferably, they are 0.01 micrometer or more and 0.5 micrometer or less. When an inorganic filler having an average particle size larger than 1 μm is used, it is difficult to make a thin film and the capacitance cannot be lowered. If it is less than 0.01 μm, the inorganic filler tends to agglomerate secondary, so the dispersion stability of the paste is poor.

  In addition, an inorganic filler having an average particle size larger than 0.5 μm may be difficult to form into a hexahedral dice. For this reason, when an inorganic filler having an average particle size larger than 0.5 μm is used, the particle shape varies greatly, and it becomes difficult to obtain an interaction with the resin via the dispersant and the surface treatment agent. If it is less than 0.01 μm, the inorganic filler tends to agglomerate secondary, so the dispersion stability of the paste is poor.

  Moreover, in order to make a resin contain an inorganic filler with high filling rate, in this invention, it is preferable to mix and use what has two or more types of different average particle sizes. When an inorganic filler having a single particle size is filled, particularly when the inorganic filler is spherical or substantially spherical, a diamond-shaped void is formed between the inorganic filler and the inorganic filler when filled with a high density. Can no longer be penetrated by other inorganic fillers. However, if the inorganic filler has a size smaller than this gap, it can further penetrate into the gap, and the filling rate can be easily improved. At this time, the inorganic filler having the minimum average particle size is preferably a hexahedral dice. It can also be used by mixing with an inorganic filler having a shape other than a hexahedral dice. Of the inorganic fillers having two different average particle sizes, the average particle size of the inorganic filler having the largest average particle size is preferably 5 μm or less. More preferably, it is 2 micrometers or less, More preferably, it is 1 micrometer or less. When an inorganic filler having an average particle size of more than 5 μm is used to produce a capacitor having a film thickness of 10 μm or less, the inorganic filler tends to protrude from the film surface, so that it is difficult to obtain stable dielectric characteristics. Moreover, when the average particle size of the inorganic filler having the maximum average particle size is 2 μm or less, the inorganic filler in the inorganic filler dispersion liquid hardly settles. Further, when an inorganic filler having the maximum average particle size and having an average particle size of 1 μm or less is used, the inorganic filler is less likely to settle during long-term storage, which is advantageous in terms of storage stability.

  Moreover, in this invention, it is preferable that the average particle size of the inorganic filler which has the minimum average particle size is 0.01-0.1 micrometer. Furthermore, it is more preferable to use a 0.04-0.06 micrometer thing. Since it is necessary to take a difference ratio between the maximum average particle size and the minimum average particle size, the inorganic filler having the minimum average particle size is appropriately selected from the above range depending on the maximum average particle size. The average particle size of the inorganic filler having the smallest average particle size can increase the filling rate when the difference ratio with the average particle size of the inorganic filler having the largest average particle size is increased. Therefore, the average particle size of the inorganic filler having the smallest average particle size is preferably 0.1 μm or less, more preferably 0.1 μm or less in view of the preferred range of the average particle size of the inorganic filler having the largest average particle size. It is 06 μm or less. When the average particle size of the inorganic filler having the minimum average particle size is 0.04 μm or more, re-aggregation after dispersion hardly occurs and the dispersion stability of the paste is good. In addition, when the average particle size of the inorganic filler having the minimum average particle size is further 0.01 μm or more, these inorganic fillers are less likely to agglomerate with each other.

  The material of the inorganic filler used in the present invention is not particularly limited, and inorganic fillers such as metal oxides and nitrides can be used.

  Preferably, barium titanate, barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, barium tin titanate, magnesium niobate Barium, magnesium barium tantalate, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, lead tungstate, tungstic acid Calcium, magnesium tungstate, titanium dioxide, or the like can be used. The barium titanate system includes solid solutions based on barium titanate, in which some elements in the barium titanate crystal are replaced with other elements or other elements are infiltrated into the crystal structure. It is a generic name. Other barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, barium tin titanate, barium magnesium niobate, magnesium tantalate Barium, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, lead tungstate, calcium tungstate, magnesium tungstic acid Both lead-based and titanium dioxide-based are the same, and are generic names including solid solutions that use each as a base material.

  In particular, it is preferable to use an inorganic filler having a perovskite crystal structure or a composite perovskite crystal structure. Of these, one kind can be used alone, or two or more kinds can be used in combination, but the inorganic filler having at least two different average particle sizes has the same chemical composition. This is preferable because stable dielectric characteristics can be obtained even when a region where only one inorganic filler is localized is generated due to poor dispersion or the like. In particular, when obtaining a dielectric composition having a high dielectric constant, it is preferable to use a compound mainly composed of barium titanate from the viewpoint of compatibility with commercial convenience. However, for the purpose of improving dielectric properties and temperature stability, a small amount of a shifter, a depressor and the like may be added.

  Examples of the method for producing the inorganic filler include solid phase reaction methods, hydrothermal synthesis methods, supercritical hydrothermal synthesis methods, sol-gel methods, and oxalate methods. As a method for producing the inorganic filler having the maximum average particle size, it is preferable to use a solid phase reaction method or an oxalate method from the viewpoint of a high relative dielectric constant and quality stability. In addition, it is preferable to use a hydrothermal synthesis method, a supercritical hydrothermal synthesis method, or a sol-gel method as the method for producing the inorganic filler having the minimum average particle size because it is easy to reduce the particle size. .

  Further, in a dielectric composition having an inorganic filler and a resin, the relative dielectric constant of the dielectric composition follows a derivation formula of a relative dielectric constant in the composite, so-called logarithmic mixing rule (4) described below (ceramic material) Introduction to Science (Applied), Uchida Otsukuru Shinsha, WDKingery, translated by Komatsu Kazuzo et al., P912). The higher the content of the inorganic filler having a high dielectric constant, the higher the relative dielectric constant of the obtained dielectric composition. Conversely, the higher the content of the inorganic filler having a low dielectric constant, the lower the relative dielectric constant of the resulting dielectric composition.

ε: relative permittivity of the composite εi: relative permittivity of each component of the composite Vi: volume fraction of each component of the composite

  In order to obtain a high relative dielectric constant, it is desirable to contain these inorganic fillers in the resin with a high filling rate. For example, a mixture of two or more types having different average particle sizes may be used. When an inorganic filler having a single particle size is filled, particularly when the inorganic filler is spherical or substantially spherical, a diamond-shaped void is formed between the inorganic filler and the inorganic filler when filled with a high density. Other inorganic fillers cannot penetrate. However, if the inorganic filler has a size smaller than this gap, it can further penetrate into the gap, and the filling rate can be easily improved.

  In addition to these large inorganic fillers and small inorganic fillers, inorganic fillers of other particle sizes may be mixed, or filling by mixing inorganic fillers by appropriately selecting the particle size and blending ratio even with three or more types The effect of rate improvement is obtained.

  As a ratio of the inorganic filler and the resin contained in the dielectric composition of the present invention, the volume percentage Vf of the inorganic filler relative to the sum of the total volume of the inorganic filler and the resin satisfies 50% or more and 95% or less. preferable. More preferably, it is 70% or more and 90% or less. When the volume percentage Vf of the inorganic filler is less than 50%, a large relative dielectric constant cannot be obtained, and the thermal expansion coefficient is large. When the volume percentage Vf of the inorganic filler is 70% or more, the effect of using the inorganic filler having at least two kinds of average particle sizes becomes remarkable, and a large relative dielectric constant is obtained. On the other hand, when the volume percentage Vf of the inorganic filler is 90% or more, the adhesiveness after PCT (pressure cooker test) which is a durability promotion test tends to be lowered. Further, when the volume percentage Vf of the inorganic filler is larger than 95%, since there are few resins that serve as a binder, the strength is low, and the adhesiveness to other base materials is lowered. Furthermore, the moisture absorption rate is large, and the physical properties are easily affected by moisture and humidity.

  The dielectric composition in the present invention may be used as an interlayer insulating material, and the resin used in that case satisfies, for example, a linear expansion coefficient of 30 to 50 ppm / ° C. for polyimide and 50 ppm / ° C. or more for epoxy resin. Resins are preferred. This is very large compared to the linear expansion coefficient of 17 ppm / ° C. of a wiring metal, for example, copper, but by mixing an inorganic filler, the linear expansion coefficient of the entire dielectric composition is lowered and the linear expansion of the wiring metal is reduced. The difference from the coefficient can be reduced.

  The resin used in the present invention is for dispersing and holding the inorganic filler, and is not particularly limited, and any of thermoplastic and thermosetting resins can be selected.

  As the thermoplastic resin, for example, polyphenylene ether, polyphenylene sulfide, polyether sulfone, polyether imide, liquid crystal polymer, polystyrene, polyethylene, fluorine resin, or the like can be used.

  Thermosetting resins include, for example, epoxy resins, phenol resins, siloxane resins, polyimides, acrylic resins, cyanate resins, benzocyclobutene resins, and other resins that are generally used for insulating layers of printed wiring boards. Can be used. From the viewpoint of solder heat resistance, it is preferable to use a thermosetting resin, and in particular, an epoxy resin is preferably used from the viewpoint of thermosetting shrinkage and viscosity.

  Here, the epoxy resin is a resin having a prepolymer containing two or more epoxy groups (oxirane rings) in the molecular structure. The prepolymer preferably has a biphenyl skeleton or a dicyclopentadiene skeleton from the viewpoint of stability of dielectric properties upon moisture absorption. Moreover, you may have a hardening | curing agent and hardening agents, such as a phenol novolak resin, a bisphenol A type novolak resin, an aminotriazine compound, a naphthol compound, can be used for a hardening | curing agent. Further, it is possible to add a curing accelerator such as a metal chelate compound such as triphenylphosphine, a benzimidazole compound, or tris (2,4-pentanedionato) cobalt.

  The paste composition in the present invention is composed of an inorganic filler, a resin and a solvent (state before solidification of the dielectric composition), and is obtained by dispersing the inorganic filler in the resin. For example, the inorganic filler is added to the resin solution and mixed and dispersed, or a dispersion in which the inorganic filler is previously dispersed in an appropriate solvent is prepared, and then the dispersion is mixed with the resin solution. The Further, the method for dispersing the inorganic filler in the resin or solvent is not particularly limited. For example, methods such as ultrasonic dispersion, ball mill, roll mill, clear mix, homogenizer, and media disperser can be used. From the viewpoint of properties, it is preferable to use a ball mill or a homogenizer.

  When dispersing the inorganic filler, in order to improve dispersibility, for example, surface treatment of the inorganic filler, addition of a dispersant, addition of a surfactant, addition of a solvent, and the like may be performed. Examples of the surface treatment of the inorganic filler include rosin treatment, acid treatment, basic treatment and the like, in addition to treatment with various coupling agents such as silane, titanium, and aluminum, fatty acids, and phosphate esters. Examples of the addition of the dispersant include dispersants having an acid group such as phosphoric acid, carboxylic acid, fatty acid, and esters thereof. In particular, compounds having a phosphate ester skeleton are preferably used. . In addition, addition of nonionic, cationic, anionic surfactants, wetting agents such as polyvalent carboxylic acids, amphoteric substances, and resins having highly sterically hindered substituents can be mentioned. Moreover, the polarity of the system at the time of dispersion or after dispersion can be controlled by addition of a solvent. Moreover, the paste composition may contain a stabilizer, a dispersant, an anti-settling agent, a plasticizer, an antioxidant, and the like, if necessary. In addition, solid content means what combined the inorganic filler, resin, and other additives.

  The inorganic filler dispersion medium and the resin solvent are not particularly limited. For example, mesitylene, acetonylacetone, methylcyclohexanone, diisobutylketone, methylphenylketone, dimethylsulfoxide, γ-butyrolactone, isophorone, diethylformamide, dimethylacetamide, N-methylpyrrolidone, γ-butyrolactam, ethylene glycol acetate, 3-methoxy-3-methylbutanol and its acetate, 3-methoxybutyl acetate, 2-ethylhexyl acetate, oxalate ester, diethyl malonate, maleate ester, propylene carbonate, Butyl cellosolve, ethyl carbitol, methyl cellosolve, N, N-dimethylformamide, methyl ethyl ketone, dioxane, acetone, cyclohexanone , Cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, toluene, chlorobenzene, trichlororetylene, benzyl alcohol, methoxymethylbutanol, ethyl lactate, propylene glycol monomethyl ether, acetate thereof, and mixtures thereof.

  The adherend to which the paste composition is applied can be selected from, for example, an organic substrate, an inorganic substrate, and those in which circuit constituent materials are arranged on these substrates. Examples of organic substrates include glass-based copper-clad laminates such as glass cloth / epoxy copper-clad laminates, composite copper-clad laminates such as glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, polyethers Examples include heat-resistant / thermoplastic substrates such as ketone resin substrates and polysulfone resin substrates, polyester copper-clad film substrates, and polyimide copper-clad film substrates.

  Examples of inorganic substrates include ceramic substrates such as alumina substrates, aluminum nitride substrates, and silicon carbide substrates, and metal substrates such as aluminum base substrates and iron base substrates. Examples of circuit components include conductors containing metals such as silver, gold and copper, resistors containing inorganic oxides, low dielectrics containing glassy materials and / or resins, resins and inorganics Examples thereof include a high dielectric material containing a filler and the like, and an insulator containing a glass-based material.

  The film thickness when the dielectric composition is formed into a film shape can be arbitrarily set within a range in which the capacitance satisfies a desired value, but is preferably 0.5 μm or more and 30 μm or less. More preferably, it is not less than 2 μm and not more than 30 μm. In order to secure a large capacitance as a capacitor, it is preferable that the film thickness is thin. However, if the thickness is less than 0.5 μm, pinholes are easily generated, and electrical insulation is difficult to obtain. When the thickness is 2 μm or more, the dielectric loss tangent hardly increases after PCT (pressure cooker test) which is a durability promotion test. On the other hand, if the film thickness exceeds 30 μm, a large relative dielectric constant is required to obtain sufficient capacitor performance, and it may be difficult to improve the mounting density.

  The use of the dielectric composition of the present invention is not particularly limited. For example, the dielectric composition of the present invention is used as an interlayer insulating material for a built-in capacitor of a printed wiring board as a high dielectric constant layer, an interlayer insulating film of a multilayer board, a frequency filter, and a radio antenna It can be applied to various electronic parts and devices such as electromagnetic shields and optical wiring materials. When used as a capacitor interlayer insulating material, the method for forming the capacitor interlayer insulating material from the dielectric composition is not particularly limited. For example, as described above, after a high dielectric is formed on a substrate, it can be obtained by appropriately forming an electrode.

The capacitance per area of the capacitor interlayer insulating material produced using the dielectric composition of the present invention is preferably in the range of 5 nF / cm ² or more. More preferably, it is in the range of 10 nF / cm ² or more. When the capacitance is less than 5 nF / cm ² , when used as a decoupling capacitor, the entire system cannot be sufficiently separated from the power supply system and cannot function sufficiently as a decoupling capacitor.

  The smaller the capacitance change in temperature and the in-plane variation, the better in terms of circuit design. The temperature change is preferably as small as possible. For example, it is preferable to satisfy the X7R characteristic (capacitance temperature change rate within −15% at −55 to 125 ° C.). The in-plane variation in capacitance is preferably 5% or less (average capacitance value−5% ≦ capacitance ≦ average capacitance value + 5%) with respect to the average value.

  In order to reduce the power loss of the power source, the dielectric loss tangent of the capacitor is preferably in the range of 0.01 to 5%, and more preferably in the range of 0.01 to 1%. Here, electrical characteristics such as capacitance and dielectric loss tangent are measured values at a frequency of 20 k to 1 GHz.

  The electrostatic capacity, relative dielectric constant, and dielectric loss tangent of the dielectric composition can be measured as follows, for example, according to JIS K6911. That is, a coating film of a high dielectric composition is formed on the entire surface of an aluminum substrate having an area of 10 cm × 10 cm and a thickness of 0.3 mm. An electrode for measurement is formed by pattern-printing a conductive paste on the coating film. A portion sandwiched between the measurement electrode and the aluminum substrate is a measurement target region. The capacitance and dielectric loss tangent of the measurement target region are measured with an impedance analyzer (for example, 4294A manufactured by Agilent Technologies). The relative dielectric constant is calculated from the capacitance and the dimension of the measurement target region. From the viewpoint of reducing measurement noise, the pattern of the measurement electrode on the coating film is circular, and a ring-shaped electrode (referred to as a guard electrode) so as to surround the circular pattern at a distance of 0.5 to 1 mm from the outer periphery of the measurement electrode. Is preferable.

  Since the dimensions of the measurement target area, that is, the diameter (area) of the measurement electrode and the film thickness of the dielectric composition affect the measurement accuracy, it is necessary to select conditions that match the physical properties of the dielectric composition. In the present invention, the measurement electrode is a circular pattern having a diameter of 10 mm, the guard electrode is a ring pattern having an inner diameter of 11.5 mm, and the film thickness of the dielectric composition is in the range of 10 μm to 20 μm. The coating film of the dielectric composition was formed by appropriately heating the spin-coated paste composition, evaporating the solvent, and curing the resin. In addition, since the temperature and moisture absorption state also affect the dielectric properties, the dielectric properties can be evaluated with good reproducibility by performing measurements after leaving the high dielectric composition in a measurement temperature constant temperature and humidity atmosphere for 24 hours. it can.

  The method for measuring the porosity of the dielectric composition can be appropriately selected according to the application, such as a gas adsorption method, a mercury intrusion method, a positron annihilation method, and a small angle X-ray scattering method. From the density of the composition, the porosity is determined by the following procedures (1) to (3).

(1) Weigh the dielectric composition obtained by applying the paste composition onto the weighed shaped substrate, removing the solvent, and solidifying it.
(2) When the weight of the substrate is W1, the weight of the substrate and the dielectric composition is W2, the density of the dielectric composition is D, and the volume is V, the density of the dielectric composition D = (W2-W1) / V.
(3) Using a thermogravimetry apparatus (TGA), the dielectric composition is heated to 900 ° C. at a temperature rising rate of 10 ° C./min in the air atmosphere and held at 900 ° C. for 30 minutes to remove the binder. And the ratio of the inorganic filler and the resin contained in the dielectric composition was measured. When the volume of the inorganic filler is Wc, the specific gravity is ρc, the volume of the resin is Wp, the specific gravity is ρp, and the porosity is P, the porosity P can be obtained by the following equation.

  Porosity P (volume%) = {(V−Wc / ρc−Wp / ρp) / V} × 100.

  By forming such a dielectric composition, the mounting substrate can be reduced in thickness, thickness, and a highly reliable capacitor can be obtained with a small occupied area. Furthermore, since it is suitable for a large capacitance, it is useful as a capacitor incorporated in a high-density SiP or an interlayer insulating material for circuit board materials having a function as a capacitor.

  Furthermore, the dielectric composition of the present invention can be preferably used as an optical wiring material. Optical wiring refers to wiring in a system in which signal transmission between LSIs, modules, boards, and the like is performed not by normal electrical signals but by optical signals. When an optical wiring is formed on or in the mounting substrate, a structure in which a layer having a high refractive index is sandwiched between layers having a low refractive index is employed. It is also possible to substitute a layer having a low refractive index with a space. When used as an optical wiring material, it is important to use an inorganic filler that is sufficiently smaller than the wavelength of the light in order to reduce the scattering of light for signal transmission guided in the optical wiring. The particle size is preferably ¼ or less. Further, the refractive index, the temperature dependency of the refractive index, and the thermal expansion coefficient can be controlled from the selection of the inorganic filler material, the content, and the resin material. As a result, the range of substrate materials for forming the optical wiring layer is widened, and it is possible to use substrates made of organic materials as well as those made of conventionally used inorganic materials such as silicon and ceramics. .

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Table 1 shows the average particle size of the inorganic filler used in the present invention and the magnification of the surface area of the inorganic filler compared to the surface area of the same volume of spheres.

The specific surface area of true spheres of the same volume was determined by the following method. An inorganic filler dispersed in a solvent and loosened in a coagulated state was dropped on a TEM observation mesh, the solvent was evaporated, and observation with a transmission electron microscope (TEM) was performed. Observation with a transmission electron microscope (TEM) was performed at magnifications of 10,000 times and 20000 times. A transmission electron microscope observation photograph of the obtained inorganic filler was analyzed using image analysis software (Scion Image, manufactured by Scion Corporation), and the area of each inorganic filler image was obtained. Each inorganic filler image thus obtained was approximated as a circle, and the particle size was calculated from the area. The particle size was calculated for all inorganic fillers in the transmission electron micrograph, and the average value was taken as the average particle size. From the particle size, the following formulas (1) to (3) were used to determine the surface area, volume, and specific surface area when the inorganic filler was assumed to be a true sphere. The specific surface area is the surface area per gram of the object, and is included in 1 g when it is assumed that the number of inorganic fillers contained in 1 g is a true sphere having an average particle size determined by _a dynamic light scattering method or the like. It can be considered that the number of inorganic fillers _nb is substantially equal.

Surface area (cm ² ) S = 4πr ² (1)
Volume (cm ³ ) V = 4 / 3πr ³ (2)
Specific surface area (cm ² / g) A = S / (V · a) (3)
S: Surface area of one true sphere r: Radius of a true sphere V: Volume of one true sphere A: Specific surface area of a true sphere of radius r a: Specific gravity of an inorganic filler.

  The specific surface area obtained from the BET method (Brunauer-Emmett-Teller Method) was compared with the specific surface area obtained by the above method when it was assumed to be a true sphere. It was calculated how many times it was compared to the sphere.

Example 1
394 parts by weight of barium titanate (manufactured by Toho Titanium Co., Ltd., SB3A, average particle size: 0.3 μm), 138 parts by weight of barium titanate (manufactured by Cabot, K-Plus16: average particle size 0.06 μm), γ- A dispersion liquid A-1 was obtained by mixing and dispersing 95 parts by weight of butyrolactone and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by Big Chemie Co., Ltd.) for 2 hours under ice cooling using a homogenizer. When the barium titanate was observed with an electron microscope, the shape of the inorganic fillers of SB3A and K-Plus16 was a hexahedral dice. 16.6 parts by weight of epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC-3000), 5.8 parts by weight of phenol novolac resin (manufactured by Nippon Kayaku Co., Ltd., “Kayahard” KTG-105), curing accelerator ( Hokuko Chemical Industries, Ltd., triphenylphosphine) 0.23 parts by weight and γ-butyrolactone 12.9 parts by weight were mixed to obtain an epoxy resin solution B-1. 100 parts by weight of dispersion A-1 and 4.9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  Also, this paste composition was applied onto a 300 μm thick aluminum substrate using a die coater, dried in an oven at 80 ° C. for 15 minutes, and then cured at 175 ° C. for 4 hours to obtain a film thickness. A dielectric composition of 10 μm was obtained. An aluminum electrode having a diameter of 11 mm is formed on this dielectric composition by vapor deposition, and the dielectric characteristics at 1 MHz are measured using an impedance analyzer (Agilent 4294A and Test Fixture Agilent: 16047E (both manufactured by Agilent Technologies)). The results measured according to K 6911 are shown in Table 2. At 1 MHz, the relative dielectric constant was 135, and the porosity was 4% by volume.

Example 2
100 parts by weight of dispersion A-1 and 5.9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 125, and the porosity was 2% by volume.

Example 3
100 parts by weight of dispersion A-1 and 12.3 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 80, and the porosity was 1% by volume.

Example 4
532 parts by weight of barium titanate (manufactured by Toho Titanium Co., Ltd., SB3A, average particle size: 0.3 μm), 95 parts by weight of γ-butyrolactone, 5.3 parts by weight of dispersing agent (BYK-W9010, manufactured by BYK Chemie) Was mixed and dispersed for 2 hours under ice cooling using a homogenizer to obtain dispersion A-2. When the barium titanate was observed with an electron microscope, the shape of the inorganic filler of SB3A was a hexahedral dice. 34.7 parts by weight of epoxy resin (Nippon Kayaku Co., Ltd., NC-3000), 12.1 parts by weight of phenol novolak resin (manufactured by Nippon Kayaku Co., Ltd., “Kayahard” KTG-105), curing accelerator ( Hokuko Chemical Industries, Ltd. (triphenylphosphine) 0.47 parts by weight and γ-butyrolactone 27.0 parts by weight were mixed to obtain an epoxy resin solution B-2. 100 parts by weight of dispersion A-2 and 15.7 parts by weight of epoxy resin solution B-2 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 73, and the porosity was 1% by volume.

Example 5
100 parts by weight of dispersion A-2 and 22.7 parts by weight of epoxy resin solution B-2 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 43, and the porosity was 0% by volume.

Example 6
Epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EPPN502H) 83.4 parts by weight, phenol novolac resin (manufactured by Dainippon Ink and Chemicals, TD-2131) 51.1 parts by weight, curing accelerator (Hokuko Chemical Industries) Co., Ltd., triphenylphosphine) 1.36 parts by weight and γ-butyrolactone 86.8 parts by weight were mixed to obtain an epoxy resin solution B-3.

  100 parts by weight of dispersion A-2 and 35.3 parts by weight of epoxy resin solution B-3 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 31, and the porosity was 0% by volume.

Example 7
100 parts by weight of dispersion A-2 and 111 parts by weight of epoxy resin solution B-2 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 10, and the porosity was 0% by volume.

Example 8
100 parts by weight of dispersion A-2 and 250 parts by weight of epoxy resin solution B-2 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 8, and the porosity was 0% by volume.

Example 9
Homogenizer 532 parts by weight of barium titanate (Cabot, K-Plus 16: average particle size 0.06 μm), 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie) Was mixed and dispersed under ice-cooling for 2 hours to obtain dispersion A-3. 100 parts by weight of dispersion A-3 and 9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 62, and the porosity was 2% by volume.

Example 10
100 parts by weight of dispersion A-3 and 35.3 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 21, and the porosity was 0% by volume.

Example 11
100 parts by weight of dispersion A-3 and 111 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition. A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 8, and the porosity was 0% by volume.

Example 12
4. 532 parts by weight of barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., ST-03: average particle size 0.3 μm), 95 parts by weight of γ-butyrolactone, dispersant (BYK-W9010, manufactured by BYK Chemie) 3 parts by weight was mixed and dispersed for 2 hours under ice cooling using a homogenizer to obtain dispersion A-4. 100 parts by weight of dispersion A-4 and 9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 51, and the porosity was 2% by volume.

Example 13
A dielectric composition was prepared and evaluated in exactly the same manner as in Example 2 except that the coating conditions were adjusted so that the film thickness was 30 μm. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 125, and the porosity was 2% by volume.

Comparative Example 1
After adding a polyvinyl alcohol aqueous solution to a barium titanate filler (manufactured by Sakai Chemical Industry Co., Ltd., BT-07, average particle size: 0.7 μm), it was wet-mixed and pulverized for 12 hours using a planetary ball mill made of Zircomia. The pulverized product was dried in a dryer at 105 ° C. for 1.5 hours, and then agglomerated particles were removed using a 325 mesh sieve screen and sized. The average particle size was 0.3 μm. Moreover, when the shape of the obtained particles was confirmed with an electron microscope, a mixture of a substantially triangular shape, a substantially rectangular shape, and a substantially elliptical shape including a crushed shape was obtained. 532 parts by weight of this barium titanate filler (BT07 pulverized product, average particle size: 0.3 μm), 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie Corp.) were mixed with a homogenizer. The mixture was dispersed for 1 hour under ice-cooling to obtain a dispersion A-5. 100 parts by weight of dispersion A-5 and 15.7 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 49, and the porosity was 9% by volume.

Comparative Example 2
394 parts by weight of barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., BT-07, average particle size: 0.7 μm), 138 parts by weight of barium titanate (BT-07 ground product, average particle size: 0.3 μm), A dispersion A-6 was obtained by mixing and dispersing 95 parts by weight of γ-butyrolactone and 5.3 parts by weight of a dispersing agent (BYK-W9010, manufactured by BYK-Chemie) for 2 hours under ice cooling using a homogenizer. 100 parts by weight of dispersion A-6 and 5.9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 85, and the porosity was 10% by volume.

Comparative Example 3
394 parts by weight of barium titanate (manufactured by Kyoritsu Material Co., Ltd., BT-HP8YF, average particle size: 7 μm), barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., BT-07, average particle size: 0.7 μm) 138 Parts by weight, 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK-Chemie) are mixed and dispersed for 2 hours under ice cooling using a homogenizer to obtain dispersion A-7. It was. 100 parts by weight of dispersion A-7 and 6.1 parts by weight of epoxy resin solution B-3 were mixed using a ball mill to prepare a paste composition.

  Using the obtained paste composition, a dielectric composition was produced and evaluated in the same manner as in Example 1 except that the film thickness was 30 μm. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 78, and the porosity was 13% by volume.

Comparative Example 4
A substantially spherical barium titanate filler was formed into a spherical shape by a spray drying method and fired. When observed with an electron microscope, the filler shape of the substantially spherical BT was substantially spherical. 532 parts by weight of this substantially spherical barium titanate filler, 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie) were mixed and dispersed for 2 hours under ice cooling using a homogenizer. Dispersion A-8 was obtained. 100 parts by weight of dispersion A-8 and 5.9 parts by weight of epoxy resin solution B-1 were mixed using a ball mill to prepare a paste composition.

  Using the obtained paste composition, a dielectric composition was produced and evaluated in the same manner as in Example 1 except that the film thickness was 30 μm. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 72, and the porosity was 19% by volume.

Example 14
Barium titanate (manufactured by Toda Kogyo Co., Ltd., T-BTO-020RF, average particle size: 0.03 μm) 532 parts by weight, γ-butyrolactone 95 parts by weight, dispersing agent (BYK-W9010) 5 .3 parts by weight was mixed and dispersed for 2 hours under ice-cooling using a homogenizer to obtain dispersion A-9. When barium titanate T-BTO-020RF was observed with an electron microscope, a hexahedral dice and a substantially spherical one were observed. The particle size when the inorganic filler is assumed to be a true sphere was obtained by analyzing a photograph obtained by observation with a transmission electron microscope using image analysis software (Scion Image, manufactured by Scion Corporation). The average particle size of T-BTO-020RF was 0.03 μm obtained by calculation using image analysis software. 12.6 parts by weight of an epoxy resin (Japan Epoxy Resin Co., Ltd., Epicoat (trade name) YX8000), 7.4 parts by weight of a curing agent (manufactured by Dainippon Ink & Chemicals, Phenolite (trade name) VH4150) Then, 0.2 parts by weight of a curing accelerator (manufactured by Hokuko Chemical Co., Ltd., triphenylphosphine) and 32 parts by weight of γ-butyrolactone were mixed to obtain an epoxy resin solution B-4. 100 parts by weight of dispersion A-9 and 9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 30, and the porosity was 4% by volume.

Example 15
Barium titanate (Toda Kogyo Co., Ltd., T-BTO-030R, average particle size: 0.04 μm) 532 parts by weight, γ-butyrolactone 95 parts by weight, dispersing agent (BYK-W9010, BYK-W9010) 5 .3 parts by weight were mixed and dispersed for 2 hours under ice-cooling using a homogenizer to obtain dispersion A-10. When barium titanate T-BTO-030R was observed with an electron microscope, a hexahedral dice and a substantially spherical one were observed. The average particle size of T-BTO-030R was determined in the same manner as in Example 14. The average particle size of T-BTO-030R was 0.04 μm. 100 parts by weight of dispersion A-10 and 9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 32, and the porosity was 3% by volume.

Example 16
394 parts by weight of barium titanate (manufactured by Toho Titanium Co., Ltd., SB3A, average particle size: 0.3 μm), barium titanate (manufactured by Toda Kogyo Co., Ltd., T-BTO-020RF, average particle size: 0.03 μm) 138 parts by weight, 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie) were mixed and dispersed for 2 hours under ice-cooling using a homogenizer, and dispersion A-11 was prepared. Obtained. 100 parts by weight of dispersion A-11 and 4.9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 125, and the porosity was 4% by volume.

Example 17
394 parts by weight of barium titanate (manufactured by Toho Titanium Co., Ltd., SB3A, average particle size: 0.3 μm), barium titanate (manufactured by Toda Kogyo Co., Ltd., T-BTO-030R, average particle size: 0.04 μm) 138 parts by weight, 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie) were mixed and dispersed for 2 hours under ice-cooling using a homogenizer, and dispersion A-12 was dispersed. Obtained. 100 parts by weight of dispersion A-12 and 4.9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 2. At 1 MHz, the relative dielectric constant was 128, and the porosity was 3% by volume.

Comparative Example 5
Barium titanate (Buhler PARTEC GmbH, Nano-BaTiO ₃ -powder, average particle size: 0.02 μm) 532 parts by weight, γ-butyrolactone 95 parts by weight, dispersing agent (BYK-W9010, BYK-W9010) 5.3 A part by weight was mixed and dispersed for 2 hours under ice-cooling using a homogenizer to obtain dispersion A-13. When the barium titanate was observed with an electron microscope, the shape of the inorganic filler of Nano-BaTiO ₃ -powder was an irregular shape as crushed. The average particle size of Nano-BaTiO ₃ -powder was determined in the same manner as in Example 14. 100 parts by weight of dispersion A-13 and 9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 25, and the porosity was 7% by volume.

Comparative Example 6
394 parts by weight of barium titanate (manufactured by Sakai Chemical Industry Co., Ltd., BT-07, average particle size: 0.7 μm), barium titanate (Buhler PARTEC GmbH, Nano-BaTiO ₃ -powder, average particle size: 0.02 μm) 138 parts by weight, 95 parts by weight of γ-butyrolactone, and 5.3 parts by weight of a dispersant (BYK-W9010, manufactured by BYK-Chemie) were mixed and dispersed for 2 hours under ice-cooling using a homogenizer, and dispersion A-14 Got. 100 parts by weight of dispersion A-14 and 4.9 parts by weight of epoxy resin solution B-4 were mixed using a ball mill to prepare a paste composition.

  A dielectric composition was prepared and evaluated in the same manner as in Example 1 except that the obtained paste composition was used. The results are shown in Table 3. At 1 MHz, the relative dielectric constant was 89, and the porosity was 10% by volume.

Cross-sectional TEM photograph of dielectric composition thin film using hexahedral dice-like inorganic filler

Claims (4)

A dielectric composition comprising an inorganic filler and a resin, wherein the average particle size of the inorganic filler is 0.01 μm or more and 1 μm or less, and the surface area of the inorganic filler is 1.05 times or more and 1.3 times the true volume of the same volume. A dielectric composition comprising an inorganic filler that is twice or less. 2. The dielectric composition according to claim 1, wherein the inorganic filler has a hexahedral cube shape. The dielectric composition according to claim 1, wherein the average particle size of the inorganic filler is 0.01 µm or more and 0.5 µm or less. Inorganic fillers are barium titanate, barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, barium tin titanate, magnesium niobate Barium, magnesium barium tantalate, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, lead tungstate, tungstic acid 2. The dielectric composition according to claim 1, wherein the dielectric composition is at least one selected from calcium, lead magnesium tungstate, and titanium dioxide.