JP7231319B2 - Conductive paste composition, method for producing conductive film using same, and multilayer capacitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a conductive paste composition, a method for producing a conductive film using the same, and a multilayer capacitor.

A multilayer capacitor is an electronic component that has a structure in which dielectric layers and electrode layers that serve as internal electrodes are alternately laminated, and that is connected to the outside through external electrodes (terminal electrodes) that are electrically connected to the electrode layers. . Such dielectric layers are known to include, for example, ceramics, mica, tantalum dioxide, aluminum oxide, and the like.

Silver has traditionally been used for electrode layers. For example, a conductive silver paste containing silver alone as a conductive metal is placed between dielectric layers and fired to form electrode layers serving as internal electrodes. However, silver is a very expensive metal, and electromigration of silver easily causes short circuits between internal electrodes.

As a countermeasure against electromigration, it is known to add a noble metal such as palladium, gold or platinum, which is less likely to cause electromigration than silver, alone or a mixture of a plurality of such noble metals to a conductive silver paste. However, since these noble metals are expensive, there is a problem that the manufacturing cost of electronic parts increases.

In Japanese Patent Application Laid-Open No. 2011-151089 (Patent Document 1), in consideration of the above manufacturing cost, a conductive paste composition is prepared by adding a base metal, particularly a base metal, to a conductive silver paste, among metal materials that are said to be resistant to electromigration. A technique related to a laminated ceramic electronic component using the above is disclosed.

JP 2011-151089 A

However, in the multilayer ceramic electronic component disclosed in Patent Document 1, in an example using an internal electrode containing aluminum particles, which is a base metal, the amount of aluminum in the internal electrode is large, so the sintering of the internal electrode is insufficient. As a result, it may become difficult to obtain the desired conductivity.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a conductive paste composition capable of obtaining a conductive film such as an electrode and a wiring having good conductivity and electromigration resistance. An object of the present invention is to provide a method for producing a conductive film using the conductive film and a multilayer capacitor.

In order to solve the above problems, the present inventors focused on the physical properties of flaky aluminum particles, such as the particle size, aspect ratio and oxygen content, and conducted extensive research. As a result, the present inventors have found that the above object can be achieved by forming a conductive film using a conductive paste composition containing flaky aluminum particles having specific physical properties. Based on this finding, the conductive paste composition, the method for producing a conductive film using the same, and the multilayer capacitor according to the present invention have the following configurations.

That is, the present invention is a conductive paste composition containing a first conductive powder and a second conductive powder, wherein the first conductive powder is silver particles, and the second conductive powder is a flake The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg / m ² or less.

The mass ratio of the silver particles to the flaky aluminum particles is preferably 85 to 99.5% by mass of the silver particles and 0.5 to 15% by mass of the flaky aluminum particles.

The flaky aluminum particles are desirably coated with an organic compound film.
The organic compound film preferably contains at least one selected from the group consisting of fatty acids, aliphatic amines, aliphatic alcohols, aliphatic esters and resins.

The conductive paste composition preferably further contains an organic vehicle and a glass frit.

The conductive paste composition contains 0.5 to 14 parts by mass of the flaky aluminum particles, 42 to 50 parts by mass of the organic vehicle, and 0.7 to 0.9 parts by mass per 100 parts by mass of the silver particles. and the above glass frit.

The glass frit is metal oxide glass containing at least one component selected _{from the} group consisting of _SiO2 , _B2O3 , ZnO, BaO, CaO, _LiO2 , MgO _{, Bi2O3} and _Al2O3 . is desirable.

The present invention relates to a method for producing a conductive film using the conductive paste composition, wherein the conductive paste composition is subjected to a dry film resist method, a coater method, a screen printing method, an offset printing method, a doctor blade method, A first step of patterning into a predetermined shape using any one of a spray coating method, an inkjet method and a photolithography method, and after the first step, the patterned conductive paste composition is subjected to a temperature of 500 to 900 ° C. and a second step of firing.

The present invention provides a multilayer capacitor containing a first conductive powder and a second conductive powder, wherein the first conductive powder is silver particles and the second conductive powder is flaky aluminum particles. The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less. .

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a conductive paste composition capable of obtaining a conductive film having good conductivity and electromigration resistance, a method for producing a conductive film using the same, and a multilayer capacitor. .

A conductive paste composition, a method for producing a conductive film using the same, and a multilayer capacitor according to the present invention will be described in detail below.

Here, in this specification, the notation of the format "X to Y" means the upper and lower limits of the range (that is, X to Y or less), and no unit is described in X, and only Y is described in units. , the units of X and Y are the same.

[Conductive paste composition]
A conductive paste composition according to the present invention includes a first conductive powder and a second conductive powder. The first conductive powder is silver particles. The second conductive powder is flaky aluminum particles. The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less.

Since the conductive paste composition according to the present invention contains the first conductive powder and the second conductive powder, it is possible to obtain a conductive film having good conductivity and electromigration resistance. . In particular, by including the flaky aluminum particles having the above-described structure as the second conductive powder, the thickness of the aluminum oxide film can be reduced as described later, so that the metal particles in the conductive film obtained by firing can be densified, and the effect of improving the conductivity of the conductive film can be obtained.

<First conductive powder>
The first conductive powder in the present invention is silver particles (purity: 98-99.999% by mass). The shape of the silver particles should not be particularly limited. For example, the silver particles are spherical or approximately spherical particles dispersed in the conductive paste composition. In some cases, the spherical or approximately spherical shape of the silver particles is crushed for some reason, and dispersed as a flat discoid shape, a substantially cylindrical shape, or the like. Therefore, when referring to "silver particles", the shape should not be limited. Furthermore, the particle size of the silver particles is expressed as volume average particle size D50, and is preferably 0.1 to 5 μm. Accordingly, when a conductive film is formed using the conductive paste composition according to the present invention, the conductive film can have good conductivity. A more preferable volume average particle diameter D50 of the silver particles is 0.15 to 5 μm.

The average particle size of the first conductive powder, that is, the volume-average particle size D50 of the silver particles can be measured by, for example, a particle size distribution measuring device (for example, product name: "Microtrac MT3300II", Nikkiso Co., Ltd.) that uses a laser diffraction scattering method as a measurement principle. (manufactured by the company) can be used for measurement. The laser diffraction scattering method is a measurement method in which the particle size of an object to be measured that exhibits the same pattern of diffracted and scattered light as a sphere with a diameter of 1 μm is regarded as 1 μm regardless of its shape. Here, D50 means that the volume occupied by particles having a particle diameter equal to or smaller than that represented by D50 accounts for 50% of the total volume. The measurement was performed at the time when the sample was put into the circulator at the time of sample loading, and when the concentration reached the proper concentration and [Ready] was displayed.

A conventionally known method can be used as a method for producing silver particles. For example, an alkali or a complexing agent is added to a silver salt-containing aqueous solution to form a silver oxide-containing slurry or a silver complex salt-containing aqueous solution, and then a reducing agent is added to reduce and deposit silver particles.

<Second conductive powder>
The second conductive powder in the present invention is flaky aluminum particles. The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less.

In the present specification, the “flake-like” of the flaky aluminum particles is derived from the shape of the particles defined as an average aspect ratio of 4 or more and 100 or less. The average aspect ratio is calculated from the ratio of the volume average particle diameter D50 of the flaky aluminum particles to the average thickness (volume average particle diameter D50 [μm]/average thickness [μm]). The volume average particle diameter D50 of the flaky aluminum particles is measured by a particle size distribution measuring device (for example, trade name: “Microtrac MT3300II”, Nikkiso Co., Ltd.) that uses the laser diffraction scattering method, which is the same measuring method as the silver particles described above. (manufactured) can be used for measurement. The measurement was performed at the time when the sample was put into the circulator at the time of sample loading, and when the concentration reached the proper concentration and [Ready] was displayed.

Further, the average thickness of the flaky aluminum particles can be obtained by a calculation method of substituting the value of the water surface diffusion area of the flaky aluminum particles measured by the method described in JIS K 5906 or the like into a specific formula. can. A more specific calculation method is as follows.

That is, first, using a glass rod, flaky aluminum particles are sufficiently dispersed in acetone and allowed to stand. After that, it is filtered, dried and its mass (g) is measured. Furthermore, the flaky aluminum particles whose mass is measured are added to the stearic mineral spirit solution and dispersed using a glass rod, the stearic mineral spirit solution is further added, heated, and then filtered. Next, the flaky aluminum particles are placed on a watch glass, the whole watch glass is submerged in the liquid surface of a water-filled trough, and an aluminum film is formed on the liquid surface using a barrier so as not to wrinkle. The coverage area A (cm ² ) of the aluminum film uniformly floating on the liquid surface is calculated by measuring the distance between the barriers to the millimeter range. Then, WCA (water surface diffusion area) is calculated by substituting these into the following formula (1). Then, the average thickness of the flaky aluminum particles can be calculated by substituting the WCA value into the following formula (2).

WCA (cm ² /g) = A (cm ² )/w (g) (1)
Average thickness (μm)=10 ⁴ /{2.5 (g/cm ³ )×WCA} (2).

The surface of the flaky aluminum particles may be coated with an organic compound film as described later. Even in that case, the presence or absence of the organic compound film does not affect the volume average particle diameter D50 of the flaky aluminum particles. Note that the average thickness of the flaky aluminum particles is always calculated without the organic compound film being coated because the organic compound film is removed with acetone.

The volume average particle diameter D50 of the flaky aluminum particles is 1 μm or more and 20 μm or less, preferably 1.5 μm or more and 15 μm or less. When the volume average particle diameter D50 of the flaky aluminum particles is less than 1 μm, the specific surface area of the particles increases, and as a result, the proportion of the aluminum oxide film in the conductive paste composition (that is, the amount of oxygen contained) increases. The contact resistance increases, and good conductivity cannot be obtained. When the volume average particle diameter D50 of the flaky aluminum particles exceeds 20 μm, the arrangement of the silver particles and the flaky aluminum particles in the conductive paste composition deteriorates, making it impossible to maintain good contact between the particles. good conductivity cannot be obtained.

The average aspect ratio of the flaky aluminum particles is 4 or more and 100 or less, preferably 8.5 or more and 60 or less. If the average aspect ratio is less than 4, it can be said that the flaky particles are insufficient, and the contact between the particles is insufficient, making it difficult to obtain the desired densification and the effect of improving conductivity. becomes. Furthermore, the thickness of the aluminum oxide film becomes thicker, making it difficult to dissolve sufficiently during firing, resulting in a decrease in conductivity of the conductive film obtained by firing. On the other hand, if the average aspect ratio exceeds 100, it can be said that the particles are excessively exfoliated, resulting in poor filling properties when made into a paste, making it impossible to obtain the desired conductivity. The method for calculating the average aspect ratio is as described above.

The ratio of oxygen content to unit surface area of the flaky aluminum particles is 15 mg/m ² or less, preferably 10 mg/m ² or less. The lower limit is 0 mg/m ² as an ideal value. When the ratio of the amount of oxygen contained to the unit surface area of the flaky aluminum particles exceeds 15 mg/m ² , the thickness of the aluminum oxide film becomes so thick that it becomes difficult to dissolve it sufficiently during firing. The conductivity of the conductive film is lowered. The contained oxygen is usually present on the surface of the exfoliated aluminum particles as an oxide film. The oxygen content increases as the proportion of the oxide film increases or as the thickness of the oxide film increases.

A method for calculating the ratio of the oxygen content to the unit surface area of the flaky aluminum particles is as follows. That is, first, the oxygen content in the flaky aluminum particles is measured by the inert gas fusion infrared absorption method. Further, the specific surface area of the flaky aluminum particles is measured by the nitrogen adsorption BET method, and the ratio between this and the oxygen content (oxygen content [mg/g]/specific surface area [m ² /g]) is calculated. Specifically, the oxygen content in the flaky aluminum particles can be measured using an oxygen/nitrogen analyzer (trade name: "EMGA-920", manufactured by HORIBA, Ltd.). The specific surface area of the flaky aluminum particles can be measured using a specific surface area/pore size distribution measuring device (trade name: "QUADRASORB SI", manufactured by Quantachrome Instruments Japan LLC). The ratio of the oxygen content to the unit surface area of the flaky aluminum particles is also the average value of the large number of flaky aluminum particles contained in the conductive paste composition.

The flaky aluminum particles can be produced by a conventionally known method. For example, it can be produced by crushing an aluminum thin film formed on the surface of a plastic film by vapor deposition after peeling it from the surface of the plastic film. Further, for example, aluminum particles obtained by a conventionally known atomization method can be pulverized using a ball mill in the presence of an organic solvent.

In general, a releasing agent such as a resin or a grinding aid such as a higher fatty acid adheres to the surface of the aluminum thin film obtained by the vapor deposition process and the surface of the flaky aluminum particles obtained by pulverizing with a ball mill. ing. In the present invention, flaky aluminum particles with such a release agent or grinding aid attached to the surface may be used, and the release agent or grinding aid is removed from the surface of the flaky aluminum particles. You can use things. The desired effects of the present invention can be achieved using any flaky aluminum particles.

When flaky aluminum particles are obtained by grinding using a ball mill, grinding aids such as fatty acids such as oleic acid and stearic acid, aliphatic amines, aliphatic amides, aliphatic alcohols, and fatty acid esters are attached. Sometimes. These have the effect of suppressing unnecessary oxidation of the surface of the flaky aluminum particles and improving the conductivity of the conductive film formed using the conductive paste composition according to the present invention.

That is, in the conductive paste composition according to the present invention, the flaky aluminum particles are preferably coated with an organic compound film. This organic compound film contains the release agent or the pulverization aid. The organic compound film that coats the surface of the flaky aluminum particles achieves better conductivity by suppressing the oxidation of aluminum in the step of baking the conductive paste composition to form a conductive film. contribute. The organic compound film may cover the entire surface of the flaky aluminum particles or may cover a portion of the flaky aluminum particles, either of which is within the scope of the present invention. The content of the organic compound film is preferably 0.05 to 2 parts by mass per 100 parts by mass of the flaky aluminum particles.

The organic compound film preferably contains at least one selected from the group consisting of fatty acids, aliphatic amines, aliphatic alcohols, aliphatic esters and resins. Specifically, fatty acids such as oleic acid, stearic acid, and lauric acid; aliphatic amines such as stearylamine and laurylamine; aliphatic alcohols such as stearyl alcohol and oleyl alcohol; , stearamide, butyl stearate, oleyl acid phosphate, 2-ethylhexyl acid phosphate, and the like. Examples of resins include acrylic resins, urethane resins, epoxy resins, polyester resins, and cellulose resins.

<Mass ratio of silver particles and flaky aluminum particles>
Here, the mass ratio of the silver particles to the flaky aluminum particles is preferably 85 to 99.5% by mass of the silver particles and 0.5 to 15% by mass of the flaky aluminum particles. Further, the conductive paste composition more preferably contains 0.5 to 14 parts by mass of flaky aluminum particles per 100 parts by mass of silver particles. More preferably, the weight ratio of the silver particles to the flaky aluminum particles is 90 to 99% by weight of the silver particles and 1 to 10% by weight of the flaky aluminum particles. Further, it is more preferable that 5 to 12 parts by mass of flaky aluminum particles are contained per 100 parts by mass of silver particles. If the content of the flaky aluminum particles is within the above range, the electromigration resistance is dramatically improved while maintaining good conductivity compared to the case where the conductive paste composition is composed of silver particles alone. be able to. When the flaky aluminum particles are coated with an organic compound film, the mass of the flaky aluminum particles means the mass including the coated organic compound film.

The mass ratio of the silver particles and the flaky aluminum particles in the conductive paste composition can be determined by weighing during preparation of the conductive paste composition.

<Organic vehicle and glass frit>
The conductive paste composition according to the present invention preferably further contains an organic vehicle and glass frit. As a result, it is possible to achieve a conductive paste composition which is excellent in coatability and printability on a substrate, and in which the adhesiveness between the conductive film obtained by firing and the substrate is improved.

(organic vehicle)
The organic vehicle can be composed by dissolving a conventionally known resin as a binder in a conventionally known organic solvent. The component of the binder resin contained in the organic vehicle should not be particularly limited. Examples of binder resins that can be used include ethyl cellulose resins, alkyd resins, polyester resins, and acrylic resins. In particular, since the conductive paste composition according to the present invention is fired after being applied to a substrate, it is preferably a binder resin that can be completely burned or decomposed depending on the firing temperature. Furthermore, as organic solvents, for example, butyl carbitol, isopropyl alcohol, toluene, glycol ether solvents, terpineol solvents and the like can be used.

The content of the organic vehicle in the conductive paste composition according to the present invention is preferably 42 to 50 parts by mass per 100 parts by mass of silver particles. When the content of the organic vehicle is within the above range, excellent applicability and printability to various substrates can be obtained. If the content of the organic vehicle is less than 42 parts by mass per 100 parts by mass of the silver particles, the viscosity of the paste becomes too high, which may make it impossible to draw wiring during patterning and prevent the flow of current. If the content of the organic vehicle exceeds 50 parts by mass per 100 parts by mass of the silver particles, the viscosity of the paste becomes too low, and adjacent wirings may come into contact with each other during patterning, resulting in an abnormal current. A more preferable content of the organic vehicle is 45 to 48 parts by weight per 100 parts by weight of silver particles.

The content of the binder resin in the organic vehicle is preferably 0.5% by mass or more and 40% by mass or less from the viewpoint of obtaining a paste with an appropriate viscosity, but should not be particularly limited.

(glass frit)
The conductive paste composition according to the present invention can contain glass frit. A conventionally known glass frit can be used for this glass frit. For example, the glass frit _is metal oxide glass containing at least one component selected from _the group consisting of _SiO2 , _B2O3 , ZnO, BaO, CaO, _LiO2 , MgO _{, Bi2O3} and _Al2O3 . is preferably Furthermore, since the glass frit is fired after the conductive paste composition according to the present invention is applied to the substrate, it is more preferable that the softening point of the glass frit is equal to or lower than the firing temperature. Examples of such glass frit include B ₂ O ₃ --SiO ₂ --ZnO system, B ₂ O ₃ --SiO ₂ --Bi ₂ O ₃ system, and B ₂ O ₃ --SiO ₂ --MgO system. . However, the composition of the glass frit contained in the conductive paste composition according to the present invention and the content of each component should not be particularly limited.

The content of glass frit in the conductive paste composition according to the present invention is preferably 0.7 to 0.9 parts by mass per 100 parts by mass of silver particles. The glass frit has the effect of improving the adhesion between the conductive film obtained by firing the conductive paste composition and the substrate. If the glass frit content is less than 0.7 parts by mass per 100 parts by mass of silver particles, the effect of improving the adhesion between the conductive film and the substrate may be insufficient. If the content of the glass frit exceeds 0.9 parts by mass per 100 parts by mass of the silver particles, segregation of the glass occurs, and the segregation of the glass may reduce the conductivity of the conductive film. A more preferable glass frit content is 0.75 to 0.8 parts by mass per 100 parts by mass of silver particles.

The volume average particle diameter D50 of the glass frit is preferably about 1 to 4 μm. However, it should not be particularly limited as long as it does not adversely affect the effects of the present invention. The volume average particle size D50 of the glass frit can be calculated by the same measuring method as for silver particles and flaky aluminum particles. The measurement was performed at the time when the sample was put into the circulator at the time of sample loading, and when the concentration reached the proper concentration and [Ready] was displayed.

From the above, when both the organic vehicle and the glass frit are contained in the conductive paste composition, the conductive paste composition according to the present invention contains 0.5 to 14 parts by mass of flaky aluminum particles per 100 parts by mass of silver particles. , 42 to 50 parts by mass of an organic vehicle, and 0.7 to 0.9 parts by mass of glass frit. With such a configuration, it is possible to provide a conductive paste composition which is excellent in conductivity and electromigration resistance, and which is capable of obtaining a conductive film having excellent adhesion to a substrate.

The mass (parts by mass) of the flaky aluminum particles, the organic vehicle and the glass frit per 100 parts by mass of the silver particles in the conductive paste composition can be determined by weighing during preparation of the conductive paste composition.

<Other additives>
The conductive paste composition according to the present invention can contain various additives as long as they do not interfere with the effects of the present invention. For example, conventionally known viscosity modifiers, surface modifiers, anti-settling agents, anti-foaming agents and the like can be contained. These can be prepared as additives contained in the conductive paste composition by mixing them with other components by stirring or kneading. These additives can be contained in the conductive paste composition in a total amount of 0 to 10% by mass.

<Method for producing conductive paste composition>
The conductive paste composition according to the present invention can be produced by, for example, a method of stirring and mixing each component using a known stirrer, a method of kneading each component with a kneader such as a roll mill, or the like. However, the method for producing the conductive paste composition should not be limited to the above method.

[Method for producing conductive film]
The method for producing a conductive film using the conductive paste composition according to the present invention includes applying the conductive paste composition to a dry film resist method, a coater method, a screen printing method, an offset printing method, a doctor blade method, or a spray coating method. A first step of patterning into a predetermined shape using either a method, an inkjet method, or a photolithography method, and after this first step, a second step of baking the patterned conductive paste composition at a temperature of 500 to 900 ° C. 2 steps.

<First step>
In the first step, the conductive paste composition is formed into a predetermined shape using any one of dry film resist method, coater method, screen printing method, offset printing method, doctor blade method, spray coating method, inkjet method and photolithography method. patterning process. That is, it is a step of forming a pattern in a predetermined shape on a substrate by coating or printing the conductive paste composition according to the present invention on the substrate using any of the methods described above.

The substrate on which the conductive paste composition is applied or printed should not be particularly limited in material, shape, and the like. However, it is preferable that the material of the substrate can withstand the baking temperature in the second step described later. Furthermore, the shape of the substrate may be a smooth planar shape, or a non-planar shape with steps or unevenness. Specific examples of the substrate material include ceramics, glass, and minerals. Examples of ceramics include metal oxides such as alumina, zirconia, and titania; examples of glasses include quartz glass, borosilicate glass, and soda glass; examples of minerals include silicate minerals such as mica. can be exemplified.

The method of applying or printing the conductive paste composition on the substrate should not be particularly limited. For example, as described above, the dry film resist method, coater method, screen printing method, offset printing method, doctor blade method, spray coating method, inkjet method, photolithography method, and the like can be employed. The number of times of application or printing may be one or more times, and in the case of application, it is also possible to apply multiple layers. The thickness of the conductive paste composition film (patterned conductive paste composition) formed on the substrate by coating or printing depends on the coating or printing method and the solid content concentration in the conductive paste composition. Although it varies, the thickness is such that the thickness of the conductive film after firing is 2 to 30 μm.

The conductive paste composition film can be subjected to drying treatment and degreasing treatment as necessary. The drying or degreasing treatment conditions at this time should not be particularly limited. Normally, the drying temperature is set at 50°C to 150°C, and the degreasing temperature is set at 250°C to 450°C. The atmosphere for the drying treatment and degreasing treatment is generally air, but should not be particularly limited.

<Second step>
The second step is a step of baking the patterned conductive paste composition at a temperature of 500 to 900° C. after the first step. Thereby, a conductive film can be formed. The firing temperature is preferably 500°C to 900°C, more preferably 550°C to 650°C. By setting such a firing temperature, defective firing due to low temperature and poor firing due to formation of an oxide film due to high temperature can be prevented. If the firing temperature is less than 500° C., the conductive film obtained after firing may be peeled off. If the baking temperature exceeds 900° C., film formation itself may become impossible.

The firing atmosphere may be air, non-oxidizing atmosphere, reducing atmosphere or vacuum, and should not be particularly limited. Even if the conductive paste composition film is fired in any firing atmosphere, a conductive film exhibiting good conductivity and good adhesion to the substrate can be obtained. A more preferable firing atmosphere is a non-oxidizing atmosphere, a reducing atmosphere or a vacuum. The non-oxidizing atmosphere is an atmosphere containing any gas such as argon, helium, nitrogen, etc., or a mixed gas atmosphere containing a plurality of these gases. particles) can be suppressed. Furthermore, a reducing atmosphere may be formed by mixing a reducing gas such as hydrogen gas with a gas such as argon, helium, or nitrogen.

The average thickness of the conductive film obtained by firing is preferably 2 to 30 μm, more preferably 3 to 15 μm. If the average thickness of the conductive film is less than 2 μm, it is too thin to cause conduction failure. The average thickness of the conductive film can be confirmed, for example, by measuring with a Digimatic standard outside micrometer device (trade name: "IP65 COOLANT PROOF Micrometer", manufactured by Mitutoyo Corporation). The average thickness of the conductive film is preferably calculated by measuring the thickness of the conductive film at three or more points on the substrate and calculating the average value.

[Multilayer Capacitor]
A multilayer capacitor according to the present invention includes the first conductive powder and the second conductive powder described above. That is, the first conductive powder is silver particles and the second conductive powder is flaky aluminum particles. The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less. The multilayer capacitor preferably includes a conductive film produced by the above-described method for producing a conductive film using the above-described conductive paste composition according to the present invention.

Since the multilayer capacitor according to the present invention includes a conductive film composed of the conductive paste composition according to the present invention, it has good conductivity and electromigration resistance, and also has excellent adhesion to the substrate. It can be provided as a multilayer capacitor including internal electrodes as electrode layers. That is, the multilayer capacitor according to the present invention is an electronic component having a structure in which dielectric layers and electrode layers serving as internal electrodes are alternately laminated, and the electrode layers are coated with the conductive paste composition according to the present invention. It is preferable to employ a configuration in which a conductive film having a structure is applied.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these.

[Preparation and Evaluation of Conductive Paste Composition and Conductive Film]
First, in this example, the flaky aluminum particles as the second conductive powder contained in the conductive paste composition were prepared by the following method or commercially available products manufactured by Toyo Aluminum Co., Ltd. were used.

That is, aluminum particles are obtained by an atomizing method, which is a conventionally known method, and the aluminum particles are pulverized by a ball mill in the presence of an organic solvent using oleic acid as a pulverizing aid to obtain a desired average thickness and volume. Flaky aluminum particles having an average particle size D50 were obtained. Therefore, the surfaces of the flaky aluminum particles contained in the conductive paste compositions of Examples 1 to 11 and Comparative Examples 1 to 6, which will be described later, are coated with oleic acid as an organic compound film.

In Comparative Examples 7 and 8, which will be described later, aluminum particles were obtained by an atomizing method, which is a conventionally known method, and the aluminum particles were ball-milled in the presence of an organic solvent without using a grinding aid such as oleic acid. It was pulverized to obtain flaky aluminum particles. Therefore, the flaky aluminum particles contained in the conductive paste compositions of Comparative Examples 7 and 8 did not have an organic compound film on their surfaces.

Furthermore, silver particles (purity: 99.5% by mass) prepared by a conventionally known method were used as the first conductive powder contained in the conductive paste composition.

In this example, the volume average particle diameter D50 of the silver particles, the average thickness and volume average particle diameter D50 of the flaky aluminum particles, the ratio of the oxygen content to the unit surface area of the flaky aluminum particles, and the average aspect ratio of the flaky aluminum particles , and the viscosities of the conductive paste compositions of Examples and Comparative Examples were measured by the following measuring method. Furthermore, the specific resistance value and migration resistance of the conductive films obtained by firing the conductive paste compositions of each example and comparative example were measured or evaluated according to the following methods.

<Average thickness>
The average thickness of the flaky aluminum particles was calculated using the method as described above. That is, by measuring the mass w (g) of the flaky aluminum particles and the covering area A (cm ² ) of the flaky aluminum particles and substituting them into the above formula (1), the WCA (water diffusion area) is calculated. Then, by substituting the WCA value into the above formula (2), the average thickness of the flaky aluminum particles was calculated.

<Volume average particle size D50>
The volume average particle diameter D50 of the silver particles and the flaky aluminum particles is measured using a particle size distribution measuring device (trade name: "Microtrac MT3300II" manufactured by Nikkiso Co., Ltd.) that uses the laser diffraction scattering method as the measurement principle as described above. was measured using

<Oxygen content per unit surface area>
The oxygen content ratio [mg/m ² ] to the unit surface area of the flaky aluminum particles was measured by the following method. First, the oxygen content in the flaky aluminum particles was measured using an oxygen/nitrogen analyzer (trade name: "EMGA-920", manufactured by HORIBA, Ltd.) by an inert gas fusion infrared absorption method. Furthermore, the specific surface area of the flaky aluminum particles was measured by the nitrogen adsorption BET method using a specific surface area/pore size distribution measuring device (trade name: "QUADRASORB SI", manufactured by Quantachrome Instruments Japan LLC). From these measured values, the ratio of the oxygen content to the unit surface area of the flaky aluminum particles (oxygen content [mg/g]/specific surface area [m ² /g]) was calculated.

<Average aspect ratio>
The average aspect ratio of the flaky aluminum particles was calculated from the ratio of the volume average particle diameter D50 measured as described above to the average thickness (volume average particle diameter D50 [μm]/average thickness [μm]).

<Viscosity>
The viscosity of the conductive paste composition of each example and comparative example was measured using an E-type digital viscometer (trade name: "HBDV-I+CP", manufactured by BROOKFIELD ENGINEERING LABORATORIES) under the conditions of 2 rpm and 25°C according to JIS Z 8803. : 2011 (liquid viscosity measurement method).

<Resistivity>
The specific resistance value of the conductive film obtained from the conductive paste composition of each example and comparative example was measured by a 4-probe type surface resistance measuring instrument (trade name: "Loresta GP", manufactured by Mitsubishi Chemical Analytic Tech Co., Ltd.). It was confirmed by measuring using Five arbitrary points on each conductive film were measured, and the average value was taken as the specific resistance value. Specifically, the dimensions of the conductive film, the average thickness of the conductive film, and the coordinates of the measurement points are input to the four-probe surface resistance measuring instrument, and the values obtained by automatic calculation are It was taken as the specific resistance value of the film. The smaller the specific resistance value, the better the conductivity. The dimension of the conductive film refers to the dimension of the maximum length and the maximum width of the pattern of the predetermined shape possessed by the conductive film.

<Average thickness of conductive film>
The average thickness of the conductive film was confirmed by measuring with a Digimatic standard outside micrometer device (trade name: "IP65 COOLANT PROOF Micrometer", manufactured by Mitutoyo Corporation). The thickness of three points on the conductive film was measured with the above device, and the average value was taken as the average thickness of the conductive film.

<Migration resistance>
The migration resistance of the conductive film obtained from the conductive paste composition of each example and comparative example was evaluated as follows. Specifically, a pattern of a predetermined shape (specifically, a comb tooth pattern (electrode width: 300 μm, distance between electrodes: 300 μm) was formed on a substrate described later using the conductive paste compositions of each example and comparative example. After that, using an insulation deterioration evaluation tester (trade name: "HiP-1000", manufactured by IMV Co., Ltd.), the maximum time is 1000 hours under the conditions of 100 V, 85 ° C., and 85% humidity, until insulation (short). It was evaluated by measuring the "short time (Hr)", which is time.

<Example 1>
In Example 1, silver particles ( Volume average particle diameter D50: 0.2 μm, specific surface area: 1.2 m ² /g), flaky aluminum particles (volume average particle diameter D50: 5.5 μm, average aspect ratio: 27.5, trade name: “6390NS” , manufactured by Toyo Aluminum Co., Ltd.) and B ₂ O ₃ —SiO ₂ —ZnO glass frit (volume average particle diameter D50: 2.5 μm) are added, and a high-speed disperser (trade name: “Homodisper 2.5 type”, (manufactured by Primix Co., Ltd.) at 1500 rpm for 10 minutes. Furthermore, the above organic solvent was added to adjust the composition and viscosity shown in Table 1 below, thereby preparing a conductive paste composition. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 99% by mass of the silver particles and 1% by mass of the flaky aluminum particles. The obtained conductive paste composition was applied onto an alumina substrate using a screen printer (trade name: "HP-320", manufactured by Newlong Seimitsu Kogyo Co., Ltd.) so as to have an average thickness of 2 to 5 μm. A conductive paste composition film patterned into a predetermined shape was formed.

After drying this conductive paste composition film in the atmosphere at 100° C. for 10 minutes, it is further degreased in the atmosphere at 350° C. for 60 minutes with a hot air dryer (trade name: “MOV-112”, manufactured by Panasonic Corporation). did Next, a conductive film was formed by firing at 600° C. for 1 minute in an air atmosphere in a firing furnace.

<Example 2>
In Example 2, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 98% by mass of the silver particles and 2% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 3>
In Example 3, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 96% by mass of the silver particles and 4% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 4>
In Example 4, a conductive paste composition having the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 5>
In Example 5, a conductive paste composition having the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to butyl carbitol acetate. made. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed on the resulting conductive paste composition in the same manner as in Example 1, except that the substrate was changed to a mica substrate.

<Example 6>
In Example 6, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed on the resulting conductive paste composition in the same manner as in Example 1, except that the substrate was changed to a glass substrate.

<Example 7>
In Example 7, the organic solvent was changed to terpineol, and aluminum particles obtained by the atomization method, which is a conventionally known method for flaky aluminum particles, were ball milled in the presence of an organic solvent and oleic acid as a grinding aid, From the same raw material as in Example 1 except that it was changed to one prepared by pulverizing so that the volume average particle diameter D50 was 1.7 μm and the average aspect ratio was 8.5, the following table was obtained in the same manner as in Example 1. A conductive paste composition prepared to have the composition and viscosity shown in 1 was prepared. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 8>
In Example 8, the organic solvent was changed to isopropyl alcohol and toluene, and the flaky aluminum particles having a volume average particle diameter D50 of 12 μm and an average aspect ratio of 60 (product A conductive paste composition having the composition and viscosity shown in Table 1 below was prepared by the same method as in Example 1 from the same raw materials as in Example 1 except that the name was changed to "TCR2150"). In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 9>
In Example 9, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 93% by mass of the silver particles and 7% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 10>
In Example 10, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 90% by mass of the silver particles and 10% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Example 11>
In Example 11, the organic solvent was changed to terpineol, and the flaky aluminum particles were changed to flaky aluminum particles having a volume average particle diameter D50 of 20 µm and an average aspect ratio of 6. The same raw material as in Example 1. A conductive paste composition having the composition and viscosity shown in Table 1 below was prepared from the mixture in the same manner as in Example 1. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 1>
In Comparative Example 1, a conductive paste composition having the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1. However, in this conductive paste composition, the mass ratio of silver particles to flaky aluminum particles was 99.5% by mass of silver particles and 0.5% by mass of flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 2>
In Comparative Example 2, a conductive paste composition prepared to have the composition and viscosity shown in Table 1 below was prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol. However, in this conductive paste composition, the mass ratio of silver particles to flaky aluminum particles was 88% by mass of silver particles and 12% by mass of flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 3>
In Comparative Example 3, the composition and viscosity shown in Table 1 below were prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the organic solvent was changed to terpineol and the flaky aluminum particles were not added. A conductive paste composition was prepared. Therefore, in this conductive paste composition, the mass ratio of silver particles to flaky aluminum particles is 100% by mass of silver particles and 0% by mass of flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 4>
In Comparative Example 4, with respect to flaky aluminum particles, aluminum particles obtained by an atomizing method, which is a conventionally known method, were ground using a ball mill in the presence of an organic solvent and oleic acid as a grinding aid, and the volume average particle diameter D50 was reduced to 0. The composition and viscosity shown in Table 1 below were prepared from the same raw materials as in Example 1 by the same method as in Example 1, except that the powder was pulverized to have an average aspect ratio of 8. A conductive paste composition was prepared. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 5>
In Comparative Example 5, the organic solvent was changed to isopropyl alcohol and toluene, and the flaky aluminum particles were spherical atomized powder manufactured by Toyo Aluminum Co., Ltd. having a volume average particle diameter D50 of 1.7 μm and an average aspect ratio of 1 ( A conductive paste composition having the composition and viscosity shown in Table 1 below was prepared by the same method as in Example 1 from the same raw materials as in Example 1 except that the product name was changed to "TFH-A02P"). In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 6>
In Comparative Example 6, the flaky aluminum particles have a volume average particle diameter D50 of 12 µm and an average aspect ratio of 120, manufactured by Toyo Aluminum Co., Ltd., flaky aluminum particles (trade name: "6340NS"), except for changing them. Using the same raw materials as in Example 1 and the same method as in Example 1, a conductive paste composition having the composition and viscosity shown in Table 1 below was prepared. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 7>
In Comparative Example 7, the flaky aluminum particles were prepared as described above (volume average particle diameter D50: 20 μm, average aspect ratio: 50) except that the same raw materials as in Example 1 were used. A conductive paste composition having the composition and viscosity shown in Table 1 below was prepared by the method. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition.

<Comparative Example 8>
In Comparative Example 8, the flaky aluminum particles were prepared as described above (volume average particle diameter D50: 62 μm, average aspect ratio: 80) except that the same raw materials as in Example 1 were used. A conductive paste composition adjusted to the composition and viscosity shown in Table 1 below was prepared by the method. In this conductive paste composition, the mass ratio of the silver particles to the flaky aluminum particles was 95% by mass of the silver particles and 5% by mass of the flaky aluminum particles. A conductive film was formed using the same method as in Example 1 on the obtained conductive paste composition. However, in the obtained conductive film, clogging occurred during printing due to the large particle size of the flaky aluminum particles, and a film with a uniform thickness could not be formed.

<Discussion>
The conductive films obtained from the conductive paste compositions of Examples 1 to 11 and Comparative Examples 1 to 8 were measured and evaluated for specific resistance and electromigration resistance by the methods described above. The results are shown in Table 2 below. In addition, what is simply described as "D50" in Table 2 means that the volume average particle diameter is D50.

As can be seen from Table 2, the conductive films obtained from the conductive paste compositions of Examples 1-11 had good conductivity and electromigration resistance. Furthermore, the conductive paste compositions of Examples 1 to 11 and the conductive films obtained therefrom did not peel off from each substrate during firing and during evaluation of migration resistance. I found it to be excellent.

On the other hand, the conductive films obtained from the conductive paste compositions of Comparative Examples 1 to 8 did not contain the second conductive powder (flaky aluminum particles) or had a volume average particle diameter D50 of 1 μm or more and 20 μm. or less, the average aspect ratio is 4 or more and 100 or less, and the ratio of the oxygen content to the unit surface area is 15 mg/m ² or less, or the mass ratio with silver particles deviated from the range of 1 to 10% by mass, good electrical conductivity and electromigration resistance could not be obtained.

In Comparative Examples 4 to 7, since it was found that the specific resistance value was large and good conductivity could not be obtained, the measurement of "short time (Hr)" for evaluating electromigration resistance was stopped. (Indicated by hatching in Table 2).

For Comparative Example 8, since a conductive film with a uniform thickness could not be obtained, the measurement of the "short time (Hr)" for evaluating the specific resistance value and electromigration resistance was stopped (see Table 2). (indicated by hatching).

[Production and Evaluation of Multilayer Capacitor]
<Example 12>
In Example 12, a multilayer capacitor was produced as follows. That is, after obtaining a conductive film by the same method as in Example 1 using the conductive paste composition of Example 10, a multilayer capacitor containing this conductive film and using (Ba, Nb)TiO ₃ as a dielectric (3.2 mm × 2.5 mm, number of layers 10) was produced.

<Example 13>
In Example 13, a multilayer capacitor was produced as follows. That is, after obtaining a conductive film by the same method as in Example 1 using the conductive paste composition of Example 10, a multilayer capacitor (3.2 mm × 2 0.5 mm and 10 layers were fabricated.

<Example 14>
In Example 14, a multilayer capacitor was produced as follows. That is, except that the glass frit was changed to a B ₂ O ₃ —SiO ₂ —ZnO-based glass frit, a conductive paste composition was prepared from the same raw materials as in Example 10 in the same manner as in Example 10, and this conductive paste composition was prepared. A conductive film was obtained using the same method as in Example 1 for the conductive paste composition. After that, a multilayer capacitor (3.2 mm×2.5 mm, 10 layers) including this conductive film and using (Ba, Nb)TiO ₃ as a dielectric was fabricated.

<Example 15>
In Example 15, a multilayer capacitor was produced as follows. That is, the flaky aluminum particles have a volume average particle diameter D50 of 5.5 μm and an average aspect ratio of 22 (trade name: “0803M”) manufactured by Toyo Aluminum Co., Ltd. A conductive paste composition was prepared by the same method as in Example 10 from the same raw materials as in Example 10. Furthermore, a conductive film was obtained using the same method as in Example 1 for this conductive paste composition. After that, a multilayer capacitor (3.2 mm×2.5 mm, 10 layers) including this conductive film and using (Ba, Nb)TiO ₃ as a dielectric was fabricated.

<Comparative Example 9>
In Comparative Example 9, a multilayer capacitor was produced as follows. That is, after obtaining a conductive film by the same method as in Example 1 using the conductive paste composition of Comparative Example 2, a multilayer capacitor including this conductive film and using (Ba, Nb)TiO ₃ as a dielectric (3.2 mm × 2.5 mm, number of layers 10) was produced.

<Comparative Example 10>
In Comparative Example 10, a multilayer capacitor was produced as follows. That is, after obtaining a conductive film in the same manner as in Example 1 using the conductive paste composition of Comparative Example 3, a multilayer capacitor containing this conductive film and using (Ba, Nb)TiO ₃ as a dielectric (3.2 mm × 2.5 mm, number of layers 10) was produced.

<Comparative Example 11>
In Comparative Example 11, a multilayer capacitor was produced as follows. That is, after obtaining a conductive film in the same manner as in Example 1 using the conductive paste composition of Comparative Example 3, a multilayer capacitor (3.2 mm × 2 0.5 mm and 10 layers were fabricated.

The capacitance and tan δ of the multilayer capacitors of Examples 12-15 and Comparative Examples 9-11 were measured. Furthermore, in order to evaluate the migration resistance, the "short time (Hr)" was also measured by the method described above. Table 3 shows the results. An LCR meter (trade name: "4278A", manufactured by HEWLETT PACKARD) was used to measure the capacitance and tan δ. Tan δ is an index indicating the degree of electrical energy loss in the dielectric, and the larger the value (%), the greater the electrical energy loss in the dielectric.

As can be seen from Table 3, the multilayer capacitors of Examples 12-15 had good characteristics in capacitance and tan δ. The migration resistance was also good. On the other hand, the multilayer capacitor of Comparative Example 9 was inferior in the numerical value of tan δ. The multilayer capacitors of Comparative Examples 10 and 11 were inferior in migration resistance.

Although the embodiments and examples of the present invention have been described above, it is originally planned to appropriately combine the configurations of the above-described embodiments and examples.

It should be considered that the embodiments and examples disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

Claims (8)

A conductive paste composition comprising a first conductive powder and a second conductive powder,
The first conductive powder is silver particles,
The second conductive powder is flaky aluminum particles,
The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less,
the silver particles are spherical, substantially spherical, or substantially cylindrical;
A conductive paste composition in which the mass ratio of the silver particles and the flaky aluminum particles is 90 to 95.24% by mass of the silver particles and 4.76 to 10 % by mass of the flaky aluminum particles. . 2. The conductive paste composition according to claim 1, wherein said flaky aluminum particles are coated with an organic compound film. 3. The conductive paste composition according to claim 2, wherein said organic compound film contains at least one selected from the group consisting of fatty acids, aliphatic amines, aliphatic alcohols, aliphatic esters and resins. The conductive paste composition according to any one of claims 1 to 3, further comprising an organic vehicle and a glass frit. The conductive paste composition contains 5 to 14 parts by mass of the flaky aluminum particles, 42 to 50 parts by mass of the organic vehicle, and 0.7 to 0.9 parts by mass of the 5. The conductive paste composition of claim 4, comprising a glass frit. The glass frit is metal oxide glass containing at least one component selected _{from the} group consisting of _SiO2 , _B2O3 , ZnO, BaO, CaO, _LiO2 , MgO _{, Bi2O3} and _Al2O3 . The conductive paste composition according to claim 4 or 5, which is A method for producing a conductive film using the conductive paste composition according to any one of claims 1 to 6,
The conductive paste composition is patterned into a predetermined shape using any one of a dry film resist method, a coater method, a screen printing method, an offset printing method, a doctor blade method, a spray coating method, an inkjet method and a photolithography method. process and
and a second step of baking the patterned conductive paste composition at a temperature of 500 to 900° C. after the first step. A multilayer capacitor comprising a first conductive powder and a second conductive powder,
The first conductive powder is silver particles,
The second conductive powder is flaky aluminum particles,
The flaky aluminum particles have a volume average particle diameter D50 of 1 μm or more and 20 μm or less, an average aspect ratio of 4 or more and 100 or less, and a ratio of oxygen content to unit surface area of 15 mg/m ² or less,
the silver particles are spherical, substantially spherical, or substantially cylindrical;
A multilayer capacitor, wherein the mass ratio of the silver particles to the flaky aluminum particles is 90 to 95.24% by mass of the silver particles and 4.76 to 10 % by mass of the flaky aluminum particles.