JP2006160934A - Paste composition and dielectric composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dielectric composition having a high dielectric constant. <P>SOLUTION: The paste composition comprises an insulating inorganic filler, a conductive nonmetallic filler, a resin and a solvent in which the content of the insulating inorganic filler is ≥40 vol.% and ≤90 vol.% based on the solid concentration of the paste composition and the content of the conductive nonmetallic filler is ≥0.1 vol.% and ≤15 vol.%. The dielectric composition comprises an insulating inorganic filler, a conductive nonmetallic filler and a resin in which the content of the insulating inorganic filler is ≥40 vol.% and ≤90 vol.% and the content of the conductive nonmetallic filler is ≥0.1 vol.% and ≤15 vol.%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paste composition and a dielectric composition that can be used for manufacturing electronic components, circuit members, component-embedded substrates and modules, and various power sources.

  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 increased, and the number of required semiconductor elements and passive components has increased. From such a background, in order to efficiently mount components, a passive component built-in type high-density mounting substrate has been demanded. In particular, a large-capacity capacitor for reducing signal noise and stably operating a semiconductor device is desired.

  As a technology for a high-density mounting substrate, there are one using a ceramic wiring substrate such as LTCC (Low temperature cofired ceramics) and one using a resin substrate in which a resin is laminated with copper foil or plated copper.

  As an interlayer insulation material for component built-in boards and module capacitors manufactured using resin materials, build-up epoxy resins, polyimide resins, phenol resins, cyanate resins, phenol resins, polyphenylene ether resins, and laminates are used. There are those made of a build-up epoxy resin, polyimide resin, phenol resin, cyanate resin, phenol resin, or polyphenylene ether resin reinforced with fibers such as glass to be formed or paper. In addition, those obtained by dispersing an inorganic filler such as silica in these resins are also used. In addition, a resin film such as aramid may be used.

On the other hand, when a capacitor requires a large capacity, a material having a large dielectric constant is required between the electrodes. In such a case, there is a technique in which a high dielectric constant inorganic filler is dispersed in a resin, and a liquid or paste-like material is applied and cured (see Patent Documents 1 to 3). In order to obtain a large capacity, a material in which a metal filler is dispersed in a resin or a material in which carbon black is dispersed has been proposed (see Patent Document 4 and Non-Patent Document 1).
JP-A-5-57852 (Claims) Japanese Patent No. 2738590 (Claims) JP 2004-172531 A (Claims) JP-A-10-190241 (Claims) Electronic Components & Technology Conference (ECTC) vol1, pp.536-541,2004.

  In the conventional method of dispersing the inorganic filler in the resin, the capacitance when the capacitor is formed is not sufficient, and a material having a higher relative dielectric constant is desired. In addition, the conventional method of dispersing a metal filler or carbon black in a resin can obtain a high dielectric constant, but it is difficult to ensure insulation by introducing a conductive filler. There is also a method of covering the metal filler with an insulating material in order to ensure insulation, but in this case, it is difficult to improve the dielectric constant, and there is a problem of achieving both high dielectric constant characteristics and insulation.

  In view of such circumstances, the present invention provides a paste composition and a dielectric composition that ensure insulation and enable formation of a high-density and large-capacity capacitor.

  That is, the present invention is a paste composition containing an insulating inorganic filler, a conductive non-metallic filler, a resin, and a solvent, wherein the content of the insulating inorganic filler is 40% by volume of the solid content concentration of the paste composition. The paste composition is characterized in that it is 90% by volume or less and the content of the conductive nonmetallic filler is 0.1% by volume or more and 15% by volume or less.

  Another aspect of the present invention is a dielectric composition containing an insulating inorganic filler, a conductive non-metallic filler, and a resin, wherein the content of the insulating inorganic filler is 40% by volume or more and 90% by volume or less. The dielectric composition is characterized in that the content of the conductive non-metallic filler is 0.1 volume% or more and 15 volume% or less.

  According to the present invention, insulation is reduced by filling a resin with an insulating inorganic filler having an appropriate average particle size in a high amount and using a conductive filler having a smaller average particle size and better dispersibility than the insulating inorganic filler. And a composition having a high dielectric constant can be formed.

  The paste composition of the present invention is a composite in which an insulating inorganic filler and a conductive filler are mixed in a resin. Moreover, a dielectric composition can be obtained by removing the solvent and solidifying the paste composition according to the present invention.

  FIG. 1 shows an example of a capacitor formed using the dielectric composition according to the present invention. The dielectric composition of the present invention is sandwiched between two external electrodes, and a specific amount of insulating inorganic filler and a specific amount of conductive filler (conductive nonmetallic filler or metal filler) are contained in the resin of the dielectric composition. Is distributed. As shown in FIG. 1, the principle of increasing the dielectric constant by containing the conductive filler is that the conductive fillers dispersed in the resin are close to each other, and an infinite number of conductive filler network structures are formed. That is, since the surface area of the two electrodes of the capacitor can be substantially increased and the distance between the electrodes can be reduced, the capacitance of the capacitor can be increased.

In the present invention, the dielectric constant of the obtained dielectric composition is defined as follows. When the dielectric constant of the composition is ε, the external electrode area of the capacitor is S, and the distance between the external electrodes is d, the capacitance C is expressed by C = ε · S / d (FIG. 2A). In the present invention, as shown in FIG. 2B, the capacitor area S and the inter-electrode distance d are made constant, and the capacitance C _p is obtained. The capacitance C _p is because it is _{C p = ε p · S /} d, when viewed as the dielectric constant of the dielectric composition of the present invention becomes epsilon _p, epsilon _p is from the electrostatic capacitance C _p Can be calculated. Further, it can be considered equivalent to a change in the relative dielectric constant ε _p / ε ₀ (ε ₀ : vacuum dielectric constant) of the interlayer insulating film between the external electrodes. This relative dielectric constant is defined as an equivalent relative dielectric constant, which is the relative dielectric constant of the dielectric composition obtained by the present invention.

  The present invention contains a specific amount of an insulating inorganic filler and a specific amount of a conductive filler, and forms a network structure as described above while ensuring insulation, resulting in a high dielectric constant. The contents of the insulating inorganic filler and the conductive filler will be described below.

  The content of the insulating inorganic filler used in the present invention is such that the ratio contained in the dielectric composition is 40% by volume or more and 90% by volume or less, more preferably 60% by volume or more. FIG. 3 shows the effect of the insulating inorganic filler according to the present invention when the content of the conductive filler is constant. By increasing the filling rate of the insulating inorganic filler as 40% by volume or more as a whole, the network structure is formed with a small content of the conductive filler (FIG. 3A), so that the insulating effect can be increased. it can. In this case, dispersibility can be improved even when a metal filler is used, and the dielectric constant can be increased with a small content. If it is less than 40% by volume, a large amount of conductive filler is required to form a network structure, and the insulating property is lowered (FIG. 3B). If it is 60% by volume or more, a large relative dielectric constant can be obtained even when the average particle size of the insulating inorganic filler is small. Further, if the filling rate of the insulating inorganic filler is larger than 90% by volume, the filling rate of the resin becomes less than 10% by volume and the adhesiveness is lowered, so that it is difficult to form a thin film.

  If the conductive filler is excessively filled, the two electrodes of the capacitor are electrically connected to each other, so that the insulating property is reduced and the dielectric constant is also reduced. Therefore, the content of the conductive non-metallic filler or the metal filler is preferably 0.1% by volume or more and 15% by volume or less in the dielectric composition. More preferably, it is 10 volume% or less. If it is less than 0.1% by volume, a network structure is not formed and the dielectric constant cannot be increased. When the filling rate of the insulating inorganic filler is large, if the content of the conductive filler exceeds 10% by volume, the insulating property is lowered. Moreover, when it exceeds 15 volume%, even when the filling rate of an insulating inorganic filler is small, insulation will fall large.

  The average particle diameter of the insulating inorganic filler used in the present invention is preferably 0.1 μm or more and 4 μm or less. More preferably, it is 0.3 μm or more and 2 μm or less. When the average particle diameter is larger than 4 μm, it is difficult to form a thin film uniformly. When the average particle diameter is smaller than 0.1 μm, it is desirable to contain a lot of conductive fillers for forming a network structure ( FIG. 3 (c)), it is difficult to obtain the effect of combining the insulation and high dielectric constant of the present invention. When the insulating inorganic filler is dispersed at 2 μm or less, the filler hardly settles, and when the insulating inorganic filler is 0.3 μm or more, the dispersed filler hardly aggregates.

  Moreover, the insulating inorganic filler which has 2 or more types of different average particle diameters can be used in order to improve the filling rate of an insulating inorganic filler. In this case, if an insulating inorganic filler having an average particle diameter of 0.1 μm or more and 4 μm or less is contained in the dielectric composition by 40% by volume or more, an insulating inorganic filler having an average particle diameter of less than 0.1 μm is included. It is possible to increase the dielectric constant and improve the insulation.

  The average particle diameter of the conductive filler is 1 μm or less, more preferably 0.3 μm or less, and it is necessary to make it smaller than the average particle diameter of the insulating inorganic filler. Further, when the average particle diameter of the conductive filler is A and the average particle diameter of the insulating inorganic filler is B, the value of A / B is preferably smaller than 1. More preferably, it is 0.5 or less. If the average particle diameter of the conductive filler exceeds 1 μm or the A / B value is 1 or more, leakage current flows between the electrodes when a capacitor is formed because insulation cannot be maintained to obtain a high dielectric constant. End up. When the average particle diameter of the conductive filler is 0.3 μm or less and the value of A / B is 0.5 or less, the network structure is formed with a small volume ratio of the conductive filler in the gaps between the insulating inorganic fillers. Therefore, it is possible to obtain a large relative dielectric constant while suppressing a decrease in insulation.

  In the present invention, the average particle size of the insulating inorganic filler and conductive filler contained in the paste composition and the dielectric composition is measured by forming a dielectric composition thin film in the film thickness direction of the thin film. It can be measured by performing XMA measurement and transmission electron microscope (TEM) observation on an ultrathin section obtained by cutting out the membrane cross section. Insulating inorganic fillers, conductive fillers, and resins have different transmittances with respect to electron beams, and therefore can be identified by differences in contrast in TEM observation images. Identification of each filler when a plurality of types of fillers are used is possible by performing elemental analysis based on XMA measurement and crystal structure analysis by electron diffraction image observation. The distribution of the area of the filler and the resin thus obtained is obtained by image analysis, and the particle diameter can be calculated from the area by approximating the filler cross-section to a circle. The particle diameter 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 the dynamic light scattering method, which measures the fluctuation of the scattered light due to the Brownian motion of the filler, and the electrophoretic light scattering method, which measures the Doppler effect of the scattered light when the filler is electrophoresed. Can be measured. Examples of laser diffraction and scattering type particle size distribution measuring apparatuses include LA-920 manufactured by Horiba, Ltd., SALD-1100 manufactured by Shimadzu Corporation, and MICROTRAC-UPA150 manufactured by Nikkiso Co., Ltd.

The insulating inorganic filler can be used as long as it has a volume resistance of 10 ⁸ Ωcm or more when pressed into a powder or as a sintered body. If the volume resistance is less than 10 ⁸ Ωcm, it is difficult to ensure insulation. Metal oxides have a large volume resistance and are excellent in chemical stability. Further, it is preferable that the dielectric properties have a large relative dielectric constant. Such metal oxides include barium titanate, barium zirconate titanate, strontium titanate, calcium titanate, and bismuth titanate. Magnesium titanate, barium neodymium titanate, barium tin titanate, barium magnesium niobate, barium magnesium tantalate, lead titanate, lead zirconate, lead zirconate titanate, lead niobate , Lead magnesium niobate, lead nickel niobate, lead tungstate, calcium tungstate, lead magnesium tungstate, titanium dioxide, and the like. 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 a 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 mixed and used. From the viewpoint of dielectric properties, the insulating inorganic filler having different average particle diameters has the same chemical composition. preferable. 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, etc. may be added.

  Examples of the method for producing the insulating inorganic filler include a solid phase reaction method, a hydrothermal synthesis method, a supercritical hydrothermal synthesis method, a sol-gel method, and an oxalate method. As a method for producing an insulating inorganic filler having a large average particle diameter of 0.1 μm or more, it is preferable to use a solid phase reaction method or an oxalate method from the viewpoint of high relative dielectric constant and quality stability. In addition, the method for producing an insulating inorganic filler having a small average particle diameter of less than 0.1 μm can be any of hydrothermal synthesis, supercritical hydrothermal synthesis, and sol-gel process because it is easy to reduce the particle diameter. It is preferable to use these.

As the conductive filler, any conductive filler can be used, and examples thereof include conductive nonmetallic fillers and metallic fillers. The conductive non-metallic filler has a resistivity of 10 ⁵ Ω / cm or less other than metal, and includes carbon black and oxide conductive filler. Carbon black includes channel black, furnace black, thermal black, acetylene black, lamp black, ketjen black, bone black, etc., depending on the raw materials and manufacturing method, and can be used as a conductive filler. Fullerenes and carbon nanotubes may be used as similar ones. The oxide conductor fillers include ITO (Indium Tin Oxide), ZnO, SnO ₂ , AZO (Aluminium-doped Zinc Oxide), GZO (Gallium-doped Zinc Oxide), and IZO (Indium-doped Zinc Oxide). InSbO ₄ , ZnMgO, CuInO ₂ , MgInO ₄ , CdO, ZnSO ₃ and the like. As the metal filler, any chemically stable material such as Cu, Ag, Al, Au, Ni, Pd, or Pt can be used. These conductive non-metallic fillers and metallic fillers are subjected to various surface treatments such as oxidation treatment, adhesion treatment, graphitization treatment, activation treatment, graft treatment, and chemical treatment for the purpose of improving dispersibility and conductivity. May be. In the present invention, carbon black that is particularly excellent in dispersibility and excellent in cost and mechanical properties can be preferably used.

  Examples of the shape of the insulating inorganic filler and the conductive filler include, but are not particularly limited to, a spherical shape, a substantially spherical shape, an elliptical spherical shape, a needle shape, a plate shape, a scale shape, and a rod shape. Among these, one kind can be used alone, or two or more kinds can be mixed and used.

  As the resin used in the present invention, both 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 containing two or more epoxy groups (oxirane rings) in the molecular structure. The epoxy resin preferably has a biphenyl skeleton or a dicyclopentadiene skeleton from the viewpoint of dielectric properties. 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. A photosensitive agent may be imparted to the resin by adding a photosensitive agent.

  The solvent used in the present invention is not particularly limited, but it is preferable that at least one of the solvents to be used has a boiling point of 160 ° C. or higher. When the boiling point of the solvent is 160 ° C. or higher, the generation of voids is suppressed and the dielectric constant of the dielectric composition can be increased. When the boiling point is lower than 160 ° C., the volatilization rate of the solvent is high, so that densification due to mass transfer during heat treatment cannot catch up, voids increase, and the dielectric constant of the dielectric composition may decrease. In addition, the solvent used in the present invention preferably has a boiling point of 300 ° C. or lower, more preferably 280 ° C. or lower. When the boiling point is higher than 280 ° C., the treatment for removing the solvent becomes high temperature, the resin is decomposed by the high temperature, and the dielectric property is deteriorated. On the other hand, when the temperature exceeds 300 ° C., the decomposition of the resin becomes more severe and the mechanical strength decreases. The solvent used in the paste composition of the present invention may be only one solvent having a boiling point of 160 ° C. or higher, but may contain other solvents as long as it contains a solvent having a boiling point of 160 ° C. or higher.

  Solvents having a boiling point of 160 ° C or higher are mesitylene, acetonylacetone, methylcyclohexanone, diisobutylketone, methylphenylketone, dimethylsulfoxide, γ-butyrolactone, isophorone, diethylformamide, dimethylacetamide, N-methylpyrrolidone, γ-butyrolactam, ethylene glycol Examples include 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 and the like.

In the present invention, a solvent containing an ester structure is preferably used, more preferably a solvent containing a lactone structure. The most preferred solvent is γ-butyrolactone (hereinafter referred to as γ-BL). The boiling point as used in the field of this invention is a boiling point under the pressure of 1 atmosphere, ie, 1.013 * 10 < ⁵ > N / m < ² >. The boiling point can be measured using a known technique and is not particularly limited. For example, the boiling point can be measured using a Swietoslawski boiling point meter.

  As other solvents used in the present invention, those capable of dissolving the resin can be appropriately selected. Solvents include, for example, methyl cellosolve, N, N-dimethylformamide, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, toluene, chlorobenzene, trichloroethylene, benzyl alcohol, methoxymethylbutanol, ethyl lactate , Propylene glycol monomethyl ether and its acetate, and organic solvent mixtures containing one or more of these are preferably used.

  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 dielectric 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 glass 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 = (W ₂ −W ₁ ) / 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 filler and the resin contained in the dielectric composition is measured. When the filler volume is W _c , the specific gravity is ρ _c , the resin volume is W _p , the specific gravity is ρ _p , and the porosity is P, the porosity P can be obtained by the following equation. Porosity P (% by volume) = {(V−W _c / ρ _c −W _p / ρ _p ) / V} × 100.

  The paste composition of the present invention can be obtained by dispersing an insulating inorganic filler and a conductive filler in a resin. For example, it is prepared by a method in which each filler is added to a resin solution and mixed and dispersed, or a dispersion in which a filler is dispersed in a suitable solvent in advance and a letdown method in which the dispersion and the resin solution are mixed. . Further, the method for dispersing the filler in the resin or solvent is not particularly limited, and for example, methods such as ultrasonic dispersion, ball mill, roll mill, clear mix, homogenizer, media disperser, etc. can be used. In this respect, it is preferable to use a ball mill or a homogenizer.

  When dispersing each filler, in order to improve dispersibility, for example, surface treatment of the 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 filler include treatment with various coupling agents such as silane, titanium, and aluminum, fatty acid, phosphate ester, rosin treatment, acid treatment, and basic treatment. 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.

  The dielectric composition of the present invention can be obtained by preparing a paste in which an insulating inorganic filler and a conductive filler are mixed in a resin and a solvent, and applying, removing the solvent, and solidifying the paste. The application of the paste is not particularly limited as long as it is a method capable of forming a thin film such as an ink jet or a dispenser, in addition to a method using a spin coater, a screen printer, a blade coater, a die coater, or the like. Examples of the solidification method include solidification by heat, light, and the like. However, since the dielectric composition of the present invention is not a sintered body, it is not necessary to completely decompose and remove the resin, and it is preferable to heat at a temperature within the heat-resistant temperature range of the electronic component, for example, 500 ° C. or less. .

  When a capacitor is formed using the dielectric composition of the present invention, any material that is generally used for circuit formation can be used without particular limitation as the material used for the external electrode. Examples of suitable materials include copper, aluminum, gold, silver, and stainless steel. A particularly preferred metal is copper or an alloy containing copper.

  The substrate used for the mounting substrate can be selected from, for example, an organic substrate, an inorganic substrate, and a substrate in which circuit constituent materials are arranged. 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 form of the dielectric composition of the present invention is not particularly limited, and can be selected according to applications such as a film shape, a rod shape, a spherical shape, etc., but a film shape is particularly preferable. The membrane here includes a film, a sheet, a plate, a pellet and the like. Of course, it is also possible to perform pattern formation according to applications such as via hole formation for conduction, adjustment of impedance, capacitance or internal stress, or provision of a heat dissipation function.

  Moreover, the film thickness of the dielectric composition in the case of forming a capacitor can be arbitrarily set within a range in which the capacitance satisfies a desired value, but is preferably 1 μm or more and 30 μm or less. More preferably, it is 2 μm or more. In order to secure a large capacitance as a capacitor, it is preferable that the film thickness is thin. However, if the thickness is smaller than 1 μm, pinholes are likely to occur. Insulation is difficult to obtain. On the other hand, if the film thickness exceeds 30 μm, a large relative permittivity and area are required to obtain sufficient capacitor performance, and it becomes difficult to improve the mounting density. The volume resistance of the dielectric composition is preferably greater than 10 kΩcm, and more preferably greater than 10 MΩcm. If it is 10 MΩcm or less, a current flows through the capacitor even when a DC voltage is applied, resulting in an increase in power consumption. In the case of 10 kΩcm or less, in addition to the increase in power consumption, the heat generation also increases, and it cannot function as an insulating material.

  The conductor layer connected to the external electrode of the capacitor can be formed by a method such as sputtering, vacuum deposition, electroless plating, electrolytic plating, or hot pressing of copper foil. These electrodes may be subjected to a surface treatment such as CZ treatment, blackening treatment, or buffing.

  The use of the paste composition and dielectric composition of the present invention is not particularly limited, but it is used for RF modules, filter circuits, amplifiers, radio antennas, electromagnetic shields, various power supplies, etc., and also applied to high frequency electronic components. Can do.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
As an insulating inorganic filler, 323 parts by weight of a barium titanate filler having an average particle size of 0.5 μm, 36 parts by weight of γ-BL, and 3.2 parts by weight of a dispersant (BYK-W9010, manufactured by BYK Chemie) were used. The mixture was dispersed for 1 hour under ice cooling to obtain a dispersion. The boiling point of γ-BL is 204 ° C. 12.8 parts by weight of an epoxy resin (Nippon Kayaku Co., Ltd., EPPN502H), 7.8 parts by weight of a phenol novolac resin (manufactured by Dainippon Ink Industries, Ltd., TD-2131), a curing accelerator (Hokuko Chemical Co., Ltd.) ), Triphenylphosphine) 0.2 parts by weight and γ-BL 21 parts by weight were mixed to obtain an epoxy resin solution. As a dispersion, an epoxy resin solution, and a conductive filler, carbon black (hereinafter referred to as CB) dispersed in γ-BL (hereinafter CB) (Degussa, LampBlack101) was mixed using a ball mill to prepare a paste. .

  This paste is applied to the entire surface of a 6 cm square aluminum substrate using a spin coater, dried in an oven at 80 ° C. for 15 minutes, and then cured at 175 ° C. for 4 hours to form a dielectric composition having a thickness of 10 μm. I got a thing. The content of the insulating inorganic filler in this dielectric composition is 68% by volume, and the conductive filler is 7.5% by volume.

Next, as a top external electrode, a circular 1 cm ² aluminum electrode was formed on the substrate by vapor deposition to obtain a capacitor structure having the aluminum substrate as the bottom external electrode. When the dielectric characteristics of this capacitor were measured using an impedance analyzer 4294A and a sample holder 16047E (both manufactured by Agilent Technologies), the equivalent relative dielectric constant calculated from the capacitance at a measurement frequency of 1 kHz was 238. The value of equivalent dielectric constant is an average value of capacitors formed at four locations. Moreover, when the resistance between the two electrodes of the capacitor was measured using a tester (CDM-03D manufactured by Custom Co., Ltd.) and an insulation test was performed, the volume resistance was a value larger than 10 kΩcm. Therefore, this sample was set in a test fixture (Keithley, Model 8009), and the volume resistance was measured with an insulation resistance meter (Keithley, Model 6517A). As a result, it was 352 kΩcm.

  Table 1 shows the measured values of equivalent dielectric constant and volume resistance. Table 1 also shows the ratio A / B of the average particle diameter A of the conductive filler and the average particle diameter of the insulating inorganic filler B.

Example 2
A capacitor was produced in the same manner as in Example 1 except that the content of the barium titanate filler was 50% by volume as the insulating inorganic filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 152. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Comparative Example 1
A capacitor was produced in the same manner as in Example 1 except that the content of the barium titanate filler was 30% by volume as the insulating inorganic filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent dielectric constant was a small value of 47. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Comparative Example 2
A capacitor was produced in the same manner as in Comparative Example 1 except that the content of the conductive filler was 15% by volume. At this time, the equivalent dielectric constant was 210, but when the insulation test was performed using a tester, the volume resistance was 52 Ωcm. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Example 3 to Example 7
A capacitor was produced in the same manner as in Example 1 except that the insulating inorganic filler used was a barium titanate filler having an average particle size of 0.2, 0.7, 1, 2, 3 μm. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm, and the measurement results of the volume resistance in the insulation resistance meter were 13 MΩcm, 320 kΩcm, 73 kΩcm, 35 kΩcm, and 12 kΩcm, respectively. It was. The equivalent relative dielectric constants were 105, 337, 550, 315, and 240, respectively. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Example 8
As the insulating inorganic filler, a capacitor was prepared in the same manner as in Example 1 except that two types of barium titanate fillers having an average particle diameter of 0.5 μm and 0.06 μm were used and the content was 75% by volume. Produced. The volume ratio of the contents having an average particle diameter of 0.5 μm and 0.06 μm is 74:26. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm, and the measurement result of the volume resistance with an insulation resistance meter was 122 kΩcm. The equivalent relative dielectric constant was a large value of 349. Table 1 shows the measured values of equivalent dielectric constant and volume resistance. The value of A / B is calculated by setting the average particle diameter of the insulating inorganic filler to 0.5 μm.

Comparative Example 3
A capacitor was fabricated in the same manner as in Example 1 except that the insulating filler used was a barium titanate filler having an average particle size of 0.06 μm. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 91. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Comparative Example 4
A capacitor was produced in the same manner as in Example 1 except that the insulating inorganic filler used was a barium titanate filler having an average particle diameter of 5 μm. At this time, when an insulation test was performed using a tester, the volume resistance was 3 kΩcm. The equivalent relative dielectric constant was 161. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Example 9
A capacitor was produced in the same manner as in Example 1 except that a strontium titanate filler having an average particle size of 0.5 μm was used as the insulating inorganic filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 118. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Example 10
A capacitor was produced in the same manner as in Example 8 except that a strontium titanate filler having an average particle diameter of 0.5 μm was used as the insulating inorganic filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 159. Table 1 shows the measured values of equivalent dielectric constant and volume resistance. The value of A / B is calculated by setting the average particle diameter of the insulating inorganic filler to 0.5 μm.

Example 11
A capacitor was produced in the same manner as in Example 1 except that titanium dioxide having an average particle diameter of 0.5 μm was used as the insulating inorganic filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 103. Table 1 shows the measured values of equivalent dielectric constant and volume resistance.

Example 12
A capacitor was produced in the same manner as in Example 1 except that ITO (Indium Tin Oxide) having an average particle diameter of 0.1 μm was used as the conductive filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 133. Table 2 shows the value of the equivalent dielectric constant and the measurement result of the volume resistance.

Example 13
A capacitor was produced in the same manner as in Example 1 except that Ag having an average particle diameter of 0.1 μm was used as the conductive filler. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 149. Table 2 shows the values of the equivalent dielectric constant and the volume resistivity.

Comparative Example 5
A capacitor was produced in the same manner as in Example 1 except that Ag having an average particle diameter of 1.4 μm was used as the conductive filler. At this time, when an insulation test was performed using a tester, the volume resistance was 3 kΩcm. The equivalent relative dielectric constant was 97. Table 2 shows the value of the equivalent dielectric constant and the measurement result of the volume resistance.

Example 14
A capacitor was produced in the same manner as in Example 1 except that a CB graft polymer having an average particle size of 0.022 μm (manufactured by Nippon Shokubai Co., Ltd., FXGIK101) was used as the conductive filler. However, the solvent in which the CB graft polymer is dispersed is N-methyl 2-pyrrolidone (NMP) and has a boiling point of 202 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm, and the measurement result of the volume resistance with an insulation resistance meter was 131 kΩcm. The equivalent relative dielectric constant was 2548. Table 2 shows the value of the equivalent dielectric constant and the measurement result of the volume resistance.

Comparative Example 6
A capacitor was fabricated in the same manner as in Example 1 except that the film thickness of the dielectric composition of the capacitor was 0.4 μm. At this time, two out of the four generated pinholes, and the dielectric properties and volume resistance could not be measured.

Example 15
A capacitor was produced in the same manner as in Example 1 except that the film thickness of the dielectric composition of the capacitor was 1.5 μm. At this time, was subjected to insulation test using a tester, the volume resistance was met 7Keiomegacm. The equivalent relative dielectric constant was 218. Table 2 shows the values of the equivalent dielectric constant and the volume resistivity.

Examples 16-18
A capacitor was fabricated in the same manner as in Example 1 except that the film thickness of the dielectric composition of the capacitor was 2, 30, and 40 μm. At this time, when an insulation test was performed using a tester, the volume resistance of each showed a value larger than 10 kΩcm. The equivalent dielectric constants were 227, 230, and 231 respectively. Table 2 shows the value of the equivalent dielectric constant and the measurement result of the volume resistance.

Comparative Example 7
A capacitor was produced in the same manner as in Example 1 except that the conductive filler was not used and the content of the barium titanate filler as the insulating inorganic filler was changed to 75.5% by volume. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 82. Table 2 shows the value of the equivalent dielectric constant and the measurement result of the volume resistance.

Examples 19-21
The same CB graft polymer as in Example 15 was used as the conductive filler, the content of the conductive filler was 1, 2, 3% by volume, and the corresponding content of the insulating inorganic filler was 81.5, 80.5, A capacitor was produced in the same manner as in Example 8 except that the content was 79.5% by volume. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent dielectric constants were 150, 243, and 510, respectively. Table 3 shows the measured values of equivalent dielectric constant and volume resistance. The value of A / B is calculated with the average particle diameter of the insulating inorganic filler being 0.5 μm.

Comparative Example 8
A capacitor was fabricated in the same manner as in Example 1 except that the same CB graft polymer as in Example 15 was used as the conductive filler, the content was 3% by volume, and no insulating inorganic filler was used. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 25. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Comparative Example 9
A capacitor was fabricated in the same manner as in Example 1 except that the content was 20% by volume using CB graft polymer as the conductive filler and no insulating inorganic filler was used. At this time, when an insulation test was performed using a tester, the volume resistance was 35 Ωcm. The equivalent relative dielectric constant was 1054. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Examples 22 and 23
A capacitor was produced in the same manner as in Example 8 except that the content of the conductive filler was 5 to 7% by volume and the content of the insulating inorganic filler was 77.5 and 75.5% by volume. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm, and the measurement results of the volume resistance in the insulation resistance meter were 120 MΩcm and 26 MΩcm, respectively. The equivalent relative dielectric constants were 208 and 243, respectively. Table 3 shows the measured values of equivalent dielectric constant and volume resistance. The value of A / B is calculated by setting the average particle diameter of the insulating inorganic filler to 0.5 μm.

Example 24
A capacitor was produced in the same manner as in Example 8 except that the content of the conductive filler was 12% by volume and the content of the insulating inorganic filler was 70.5% by volume. At this time, when an insulation test was performed using a tester, the volume resistance was 830 Ωcm. The equivalent relative dielectric constant was 423. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Comparative Example 10
A capacitor was produced in the same manner as in Example 1 except that the content of the conductive filler was 16% by volume and the content of the insulating inorganic filler was 66.5% by volume. At this time, when an insulation test was performed using a tester, the volume resistance was 46 Ωcm. The equivalent relative dielectric constant was 420. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Example 25
A capacitor was produced in the same manner as in Example 1 except that ethyl carbitol was used in place of γ-BL as a solvent for dispersing the insulating inorganic filler and conductive filler. The boiling point is 202 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 228. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Example 26
A capacitor was produced in the same manner as in Example 1 except that 4-methylcyclohexanone was used instead of γ-BL as a solvent for dispersing the insulating inorganic filler and the conductive filler. The boiling point is 169 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 211. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Example 27
A capacitor was produced in the same manner as in Example 1 except that dimethylacetamide was used in place of γ-BL as a solvent for dispersing the insulating inorganic filler and conductive filler. The boiling point is 165 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was 216. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Example 28
A capacitor was produced in the same manner as in Example 1 except that morpholine was used instead of γ-BL as a solvent for dispersing the insulating inorganic filler and the conductive filler. The boiling point is 128 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. The equivalent relative dielectric constant was as small as 128. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

Example 29
A capacitor was produced in the same manner as in Example 1 except that propylene glycol monomethyl acetate was used in place of γ-BL as a solvent for dispersing the insulating inorganic filler and conductive filler. The boiling point is 146 ° C. At this time, when an insulation test was performed using a tester, the volume resistance showed a value larger than 10 kΩcm. Further, the equivalent relative dielectric constant was a small value of 139. Table 3 shows the measured values of equivalent dielectric constant and volume resistance.

An example of a capacitor structure illustrating the present invention Explanatory drawing of equivalent dielectric constant in the present invention The figure which shows the effect of the insulating inorganic filler by this invention

Explanation of symbols

1, 2 External electrode 3 Resin 4 Insulating inorganic filler 5 Conductive filler 6 Dielectric composition 7 of the present invention Network structure of conductive filler

Claims (11)

A paste composition containing an insulating inorganic filler, a conductive nonmetallic filler, a resin, and a solvent, wherein the content of the insulating inorganic filler is 40% by volume or more and 90% by volume or less of the solid content concentration of the paste composition, A paste composition, wherein the content of the conductive non-metallic filler is 0.1 volume% or more and 15 volume% or less. A paste composition containing an insulating inorganic filler, a metal filler, a resin, and a solvent, wherein the average particle size of the metal filler is smaller than the average particle size of the insulating inorganic filler, and the average particle size of the insulating inorganic filler is It is 0.1 μm or more and 4 μm or less, the content of the insulating inorganic filler is 40% by volume or more and 90% by volume or less of the solid content concentration of the paste composition, and the content of the metal filler is 0.1% by volume or more and 15% by volume or less. A paste composition characterized by the above. The paste composition according to claim 1, wherein the conductive non-metallic filler is at least one selected from carbon black and conductive oxide. The paste composition according to claim 1 or 2, wherein the insulating inorganic filler is a metal oxide. The paste composition according to claim 4, wherein the insulating inorganic filler is barium titanate. A dielectric composition containing an insulating inorganic filler, a conductive nonmetallic filler, and a resin, wherein the content of the insulating inorganic filler is 40% by volume or more and 90% by volume or less, and the content of the conductive nonmetallic filler is 0 1 to 15% by volume of a dielectric composition, A dielectric composition comprising an insulating inorganic filler, a metal filler, and a resin, wherein the average particle size of the metal filler is smaller than the average particle size of the insulating inorganic filler, and the average particle size of the insulating inorganic filler is It is 0.1 μm or more and 4 μm or less, the content of the insulating inorganic filler is 40% by volume or more and 90% by volume or less, and the content of the metal filler is 0.1% by volume or more and 15% by volume or less. Dielectric composition. 7. The dielectric composition according to claim 6, wherein the conductive non-metallic filler is at least one selected from carbon black or conductive oxide. The dielectric composition according to claim 6 or 7, wherein the insulating inorganic filler is a metal oxide. 10. The dielectric composition according to claim 9, wherein the insulating inorganic filler is barium titanate. A capacitor having the dielectric composition according to any one of claims 6 to 10 between two electrodes, wherein the dielectric composition has a thickness of 1 µm to 30 µm.

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