Multilayer ceramic electronic component, conductive material, and method for manufacturing multilayer ceramic electronic component

Abstract

Provided is a multilayer ceramic electronic component having improved conductivity of an external electrode provided on a surface of a ceramic element and having excellent contacting properties with an internal electrode disposed in the interior of the ceramic element.　The external electrode includes a conductive metal and silicon-containing glass. The conductive metal includes silver and copper, the silver component being larger in volume ratio than the copper component. The silver and copper are present in the states of silver particles (11), copper particles (12), and bonded particles (13) obtained by bonding the silver particles (11) and copper particles (12). The bonded particles (13) have a flat shape, and other than the surfaces of the bonded particles (13) where the silver particles (11) and copper particles (12) are bonded together, copper is not present on the surface of the silver particles (11) and silver is not present on the surface of the copper particles (12). A portion of the copper included in the external electrode is diffused to the internal electrode.

Description

Multilayer ceramic electronic component, conductive material, and method for manufacturing a multilayer ceramic electronic component

[0001] The present invention relates to a multilayer ceramic electronic component, a conductive material, and a method for manufacturing a multilayer ceramic electronic component, and more particularly to a structure of external electrodes provided on the surface of a ceramic body included in the multilayer ceramic electronic component, a conductive material for forming the external electrodes, and a method for manufacturing a multilayer ceramic electronic component using this conductive material.

[0002] As a technology of interest to this invention, for example, Japanese Patent No. 6056388 (Patent Document 1) describes a method for manufacturing a multilayer ceramic capacitor. In the technology described in Patent Document 1, a metal oxide precursor solution such as a sol-gel material or an MOD material that becomes a metal oxide by heat treatment is used to thin the external electrodes. By using the metal oxide precursor solution, the amount applied to the ceramic body can be reduced, and as a result, the external electrodes can be made thinner.

[0003] The metal oxide film is subjected to a reduction heat treatment to precipitate a metal. This metal becomes the underlying metal film that ensures contact with the internal electrodes. Microscopically, this underlying metal film is a film-like aggregate of numerous metal particles adhered to each other. The particle diameter of the metal particles is approximately 0.1 to 1 μm, and therefore the thickness of the underlying metal film is 0.1 to 1.0 μm on each coated surface. The material of the metal particles is, for example, Cu, Ni, W, Mo, Nb, Ta, Ti, or Zr.

[0004] To form the metal underlayer, for example, a solution is used in which a CuO coating solution and an ITO coating solution are mixed in a ratio of 7:3. This solution is heat-treated in air at 480°C for 40 minutes to oxidize the metal compounds, and then heat-treated in a reducing atmosphere at 450°C for 40 minutes to reduce part of the metal oxides.

[0005] In the technology described in Patent Document 1, a sealing metal film having a higher density than the underlying metal film is formed to prevent the plating solution from penetrating through the underlying metal film. The sealing metal film is made of, for example, Cu, Ni, W, Mo, Nb, Ta, Ti, or Zr. Since the sealing metal film is preferably thicker than the underlying metal film, it is formed by a method such as sputtering, vapor deposition, or CVD, which allows for easy film thickness control.

[0006] Patent No. 6056388

[0007] In the technology described in Patent Document 1, the metal base layer is presumed to contain ITO and CuO, which remains as a result of the reduction and precipitation of Cu. Therefore, the metal base layer has many gaps between particles and a low density, which is thought to result in poor conductivity and insufficient sealing against plating solutions and water vapor. The formation of a metal seal film, which is a measure to improve sealing, not only hinders the thinning of external electrodes, but also increases the number of processes.

[0008] Furthermore, it is believed that a film having a thickness of 0.1 to 1.0 μm obtained by applying the material and heat treatment described in Patent Document 1 does not have sufficient contact with the internal electrodes containing Ni or the like as a conductive component.

[0009] Therefore, an object of the present invention is to provide a multilayer ceramic electronic component in which the electrical conductivity of external electrodes provided on the surface of a ceramic body is improved and which has excellent contact with internal electrodes arranged inside the ceramic body, and to provide a conductive material for forming the external electrodes and a method for manufacturing a multilayer ceramic electronic component using this conductive material.

[0010] In order to solve the above-mentioned technical problems, the present invention provides an improved structure of external electrodes in a multilayer ceramic electronic component, a conductive material for forming such improved external electrodes, and a method for manufacturing a multilayer ceramic electronic component using this conductive material.

[0011] A ceramic electronic component according to the present invention comprises a ceramic body having a plurality of laminated ceramic layers and internal electrodes arranged along interfaces between the ceramic layers, and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes.

[0012] The external electrode contains a conductive metal and silicon-containing glass, the conductive metal containing silver and copper, with the silver component exceeding the copper component by volume, and the silver and copper are present in the form of silver particles, copper particles, and bonded particles in which silver particles and copper particles are bonded together. The bonded particles are flat, and copper is not present on the surface of the silver particles except at the bonded surfaces between the silver particles and the copper particles, and silver is not present on the surface of the copper particles. Furthermore, some of the copper contained in the external electrode is diffused into the internal electrode.

[0013] The conductive material according to the present invention includes a conductive metal salt in a sol state that becomes a conductive metal as a conductive component when fired, a glass frit containing a metal salt for glass that becomes a silicon-containing glass when fired, and a solvent for dissolving or dispersing the conductive metal salt and the glass frit. The ratio of the content of the glass frit to the content of the conductive metal salt is 0.04 or more and 1.40 or less, calculated in terms of the mass of the conductive metal salt after metallization and the mass of the glass frit after vitrification. The conductive metal salt includes a silver salt and a copper salt, and the ratio of the volume of the silver salt after metallization to the volume of the copper salt after metallization exceeds 1.

[0014] A method for manufacturing a multilayer ceramic electronic component according to the present invention is a method for manufacturing a multilayer ceramic electronic component comprising: a ceramic body having a plurality of laminated ceramic layers and internal electrodes arranged along the interfaces between the ceramic layers; and external electrodes provided on the surfaces of the ceramic body and electrically connected to the internal electrodes, the method comprising the steps of: applying the conductive material according to the present invention to the surfaces of the ceramic body so as to contact the internal electrodes; heating and drying the applied conductive material at a temperature of 145°C or higher; and then firing the conductive material to form the external electrodes.

[0015] In the multilayer ceramic electronic component according to the present invention, a portion of the copper in the external electrodes is diffused into the internal electrodes, thereby achieving good contact between the external and internal electrodes. Furthermore, in the external electrodes, the silver does not diffuse into the internal electrodes, and some of the silver particles are bonded to the copper particles, forming flat, bonded particles that facilitate contact between the particles. Therefore, good electrical conductivity and good plating adhesion can be achieved within the external electrodes.

[0016] The conductive material according to the present invention contains more silver than copper by volume, and therefore, when fired, flattened bonded particles in which silver particles and copper particles are bonded are easily formed. This facilitates particle-to-particle contact, enabling good conductivity to be achieved in a conductive film, such as an external electrode, formed using the conductive material. Furthermore, since the conductive material is in a sol state, the solvent and reaction by-products are removed as the gelation and vitrification proceeds through heat treatment. This results in volumetric shrinkage in the thickness direction in a conductive film, such as an external electrode, formed using the conductive material, which is advantageous for thinning the conductive film.

[0017] According to the method for producing a multilayer ceramic electronic component of the present invention, the conductive material is heated and dried at a temperature of 145° C. or higher, thereby precipitating silver particles before firing, and thus allowing the silver particles to grow before bonding the silver particles and copper particles together in the firing step. This is advantageous for growing flat bonding particles and forming thin-film external electrodes.

[0018] 1 is a cross-sectional view schematically showing a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to a preferred embodiment of the present invention; FIG. 2 is a cross-sectional view schematically showing an enlarged view of a portion of the multilayer ceramic capacitor 1 shown in FIG. 1 where an external electrode 6 is provided; FIG. 3 is a view showing an STEM image of a cross section of an external electrode of a multilayer ceramic capacitor according to an example produced in an experimental example; FIG. 4 is a view showing an EDX image of a cross section of the external electrode shown in FIG. 3; FIG. 5 is a view showing an Ag region highlighted in the EDX image shown in FIG. 4; FIG. 6 is a view showing a Cu region highlighted in the EDX image shown in FIG. 6; FIG. 7 is a view showing an EDX image of a cross section of an external electrode of a multilayer ceramic capacitor according to comparative example 1 produced in an experimental example; FIG. 8 is a view showing an Ag region highlighted in the EDX image shown in FIG. 8; FIG. 9 is a view showing an Cu region highlighted in the EDX image shown in FIG. 10; FIG. 11 is a view showing an STEM image of a cross section of an external electrode of a multilayer ceramic capacitor according to comparative example 2 produced in an experimental example;

[0019] Referring to FIG. 1, the structure of a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to one embodiment of the present invention will be described.

[0020] The multilayer ceramic capacitor 1 includes a ceramic body 2. The ceramic body 2 includes a plurality of stacked ceramic layers 3 and a plurality of internal electrodes 4 and 5 arranged along the interfaces between the plurality of ceramic layers 3. The internal electrodes 4 and 5 are classified into a plurality of first internal electrodes 4 and a plurality of second internal electrodes 5 arranged alternately in the stacking direction of the ceramic body 2. A first external electrode 6 and a second external electrode 7 are provided on the surface of the ceramic body 2, more specifically, on each of the opposing end faces. The first external electrode 6 is electrically connected to the first internal electrode 4, and the second external electrode 7 is electrically connected to the second internal electrode 5.

[0021] The ceramic layer 3 is made of, for example, ABO ３ (A is at least one of Ba, Ca and Sr, and B is at least one of Ti and Zr) as a main component.３ The alloy may contain at least one of Mn, Mg, Si, Y, Dy and Gd as a secondary component.

[0022] The internal electrodes 4 and 5 contain, as a conductive component, a conductive metal or an alloy containing the same, for example, one selected from nickel, copper, silver, and a silver / palladium alloy, and preferably contain nickel in particular.

[0023] The external electrodes 6 and 7 are formed by applying a conductive material, which will be described later, to the end faces of the ceramic body 2 so as to contact the ends of the internal electrodes 4 and 5, and then baking the applied material. In Fig. 2, a portion of the first external electrode 6 is shown in cross section. Note that the second external electrode 7, although not shown in Fig. 2, has substantially the same configuration as the first external electrode 6. Therefore, only the first external electrode 6 will be described, and a description of the second external electrode 7 may be omitted. A plating film 8 (not shown in Fig. 1) is formed on the external electrodes 6 and 7.

[0024] The external electrodes 6 and 7 contain a conductive metal and silicon-containing glass, and the conductive metal contains silver and copper, with the silver content exceeding the copper content by volume. The structures of the external electrodes 6 and 7 will be described with reference to drawings of cross-sectional images of external electrodes of a multilayer ceramic capacitor fabricated in an experimental example described below. Fig. 3 is a STEM image of the cross-section of the external electrode, and Fig. 4 is an EDX image of the cross-section of the external electrode shown in Fig. 3. Fig. 5 is an EDX image of Fig. 4 with the Ag region emphasized, and Fig. 6 is an EDX image of Fig. 4 with the Cu region emphasized.

[0025] In particular, in Fig. 4, the silver particles 11 appear as white granular regions, and the copper particles 12 appear as gray granular regions. In Fig. 5, the regions where the silver particles 11 exist are highlighted whiter, and in Fig. 6, the regions where the copper particles 12 exist are highlighted whiter.

[0026] 3 to 6 , in the external electrode, silver and copper are present in the form of silver particles 11, copper particles 12, and joined particles 13 in which silver particles 11 and copper particles 12 are joined together. Joined particles 13 are flat. Except for the joined surfaces of silver particles 11 and copper particles 12 in joined particles 13, no copper is present on the surfaces of silver particles 11 and no silver is present on the surfaces of copper particles 12.

[0027] 2, some of the copper contained in the external electrode 6 is diffused into the internal electrode 4. As a result, good contact can be obtained between the external electrodes 6 and 7 and the internal electrodes 4 and 5, since some of the copper in the external electrodes 6 and 7 is diffused into the internal electrodes 4 and 5.

[0028] Furthermore, in the external electrodes 6 and 7, silver does not diffuse into the internal electrodes 4 and 5, and as described above, some of the silver particles 11 are bonded to the copper particles 12 to form flat bonded particles 13, making it easy for the particles to come into contact with each other. Therefore, good electrical conductivity and good plating adhesion can be achieved within the external electrodes 6 and 7.

[0029] The multilayer ceramic capacitor 1 is manufactured, for example, through the following steps. First, a ceramic slurry containing ceramic raw material powder having the above-described composition is prepared. Next, the ceramic slurry is formed into ceramic green sheets using an appropriate sheet forming method. Next, a conductive paste to form each of the internal electrodes 4 and 5 is applied by printing or the like to predetermined ceramic green sheets among the plurality of ceramic green sheets. Next, the plurality of ceramic green sheets are stacked and then pressed together to obtain a green ceramic body. Next, the green ceramic body is fired. In this firing step, the ceramic green sheets become the ceramic layers 3. Thereafter, a step of forming external electrodes 6 and 7 on the end faces of the ceramic body 2 is performed, followed by a step of forming plating films 8 on the external electrodes 6 and 7.

[0030] The conductive material for forming the external electrodes 6 and 7 includes a conductive metal salt that becomes a conductive metal as a conductive component when fired, a glass frit that contains a metal salt for glass and becomes a silicon-containing glass when fired, and a solvent that dissolves or disperses the conductive metal salt and the glass frit. The ratio of the content of the glass frit to the content of the conductive metal salt is 0.04 to 1.40, calculated as the mass of the conductive metal salt after metallization and the mass of the glass frit after vitrification. The conductive metal salt includes a silver salt and a copper salt, and the ratio of the volume of the silver salt after metallization to the volume of the copper salt after metallization exceeds 1.

[0031] Such a conductive material is initially in a sol state and is applied to each of the opposing end faces of the ceramic body 2, and then heated and dried to form a gel. Thereafter, the gel is fired at a temperature equal to or higher than the softening point and lower than the melting point of the glass raw material, thereby vitrifying the glass raw material.

[0032] In the heat drying step, a temperature of 145°C or higher is applied. This allows silver particles to precipitate before firing, allowing the silver particles to grow before bonding the silver particles and copper particles in the firing step. This is advantageous for growing flat bonding particles and forming thin-film external electrodes.

[0033] In the heat drying step, a temperature of 145° C. or higher is applied, so the solvent contained in the conductive material preferably has a boiling point of 145° C. or lower. For example, 2-methoxyethanol is advantageously used as the solvent.

[0034] Furthermore, since the conductive material contains more silver than copper by volume, flat joined particles 13 in which silver particles 11 and copper particles 12 are joined are likely to be produced when fired. This allows the particles to easily contact each other, and good conductivity can be obtained in the external electrodes 6 and 7 formed with the conductive material. Furthermore, the conductive material is initially in a sol state, and as gelation and vitrification progress through heat treatment, the solvent and reaction by-products are removed, so that volume shrinkage occurs in the thickness direction in the external electrodes 6 and 7 formed with the conductive material, which is advantageous for thin film formation.

[0035] The glass raw materials contained in the conductive material preferably contain nanosilica and boric acid in addition to the metal salt for glass.

[0036] Metal salts for glass as glass raw materials include, for example, lithium nitrate and sodium nitrate.

[0037] The silver salt contained in the conductive material includes, for example, one of silver carboxylate and silver nitrate, and the copper salt includes, for example, one of copper carboxylate and copper nitrate.

[0038] The conductive material may contain an organic binder to adjust viscosity, etc. Hydroxypropyl cellulose, for example, is advantageously used as the organic binder.

[0039] Although not shown in detail, the plating film 8 formed on the external electrodes 6 and 7 is composed of, for example, a Cu plating layer, an Ni plating layer thereon, and an Sn plating layer thereon.

[0040] While the present invention has been described above in relation to the external electrodes of a multilayer ceramic capacitor, the present invention can also be applied to multilayer ceramic electronic components other than multilayer ceramic capacitors, as long as the multilayer ceramic electronic component includes a ceramic body having a laminated structure, the ceramic body having a plurality of laminated ceramic layers and internal electrodes arranged along the interfaces between the ceramic layers, and external electrodes electrically connected to the internal electrodes are provided on the surfaces of the ceramic body.

[0041] Next, an example of an experiment carried out to confirm the effects of the present invention will be described.

[0042] [Example] <Preparation of Conductive Material> A conductive material in a sol state was prepared containing the following (1) to (8): (1) tetraethoxysilane: 2.23 mass%, (2) boric acid: 0.38 mass%, (3) lithium nitrate (melting point: 260°C): 0.20 mass%, (4) sodium nitrate (melting point: 306°C): 0.27 mass%, (5) silver nitrate: 7.60 mass%, (6) copper (II) nitrate trihydrate: 11.02 mass%, (7) hydroxypropyl cellulose (2.0 to 2.9 @ 20°C / 2% aqueous solution): 11.60 mass%, and (8) 2-methoxyethanol: 54.71 mass%.

[0043] The above (1) to (4) are glass raw materials that become glass when fired, and (3) and (4) are metal salts for glass. (5) is a silver salt that becomes silver when fired. (6) is a copper salt that becomes copper when fired. (7) is an organic binder. (8) is a solvent.

[0044] The compositions of the conductive materials according to the examples are also shown in Table 1 below.

[0045] <Coating and Firing> An end surface of a ceramic body for a multilayer ceramic capacitor (0.6 mm × 0.3 mm × 0.3 mm) having Ni internal electrodes was immersed in the sol-like conductive material, and the conductive material was then gelled by drying for 10 minutes at 150° C. The opposite end surface of the ceramic body was similarly immersed and dried.

[0046] Next, N ２ Hydrogen gas was introduced into the glass raw material, and the glass raw material was fired at 700° C., which was above the softening point and below the melting point, to form external electrodes.

[0047] <Structural analysis of external electrodes> Structural analysis was performed on the sample external electrodes at the center of the surfaces extending in the width and thickness directions of the multilayer ceramic capacitor using STEM (Hitachi High-Tech's scanning electron microscope "HD-2300A") and EDX (EDAX's energy dispersive X-ray spectrometer "Genesis XM4"). As a result, the STEM image shown in Figure 3 and the EDX images shown in Figures 4 to 6 were obtained. Note that Figure 5 is an image in which the Ag region is emphasized in the EDX image shown in Figure 4, and Figure 6 is an image in which the Cu region is emphasized in the EDX image shown in Figure 4.

[0048] In Figures 3 to 6, representative silver particles 11, copper particles 12, and bonded particles 13 formed by bonding silver particles 11 and copper particles 12 are given the reference numerals "11," "12," and "13," respectively.

[0049] 3 to 6 , flat-shaped joined particles 13 were confirmed in which silver particles 11 and copper particles 12 were joined together. It was also confirmed that, other than the joining surfaces of silver particles 11 and copper particles 12 in joined particles 13, no copper was present on the surfaces of silver particles 11 and no silver was present on the surfaces of copper particles 12.

[0050] <Plating> Electrolytic Cu, Ni, and Sn plating were sequentially performed on the external electrodes under the following conditions to form plating films.

[0051] (Cu plating conditions) Plating bath type: Cu pyrophosphate plating bath (pH = 8.6) Bath temperature: 55°C Current value: 10 A Plating time: 90 minutes.

[0052] (Ni plating conditions) Type of plating bath: Watts bath (pH = 4.0), Bath temperature: 60°C, Current value: 6 A, Plating time: 51 minutes.

[0053] (Sn plating conditions) Type of plating bath: neutral plating bath (pH = 6.0), Bath temperature: 25°C, Current value: 3 A, Plating time: 66 minutes.

[0054] <Evaluation of Bonding Between Internal and External Electrodes> The obtained multilayer ceramic capacitor samples were dried at 150° C. for 1.5 hours and left to stand for 24 hours, after which the capacitance and dielectric loss tangent were measured.

[0055] Subsequently, a voltage of 25 V was applied to each sample for 5 seconds, and then the sample was dropped onto a stainless steel plate to discharge (0 Ω discharge). This was repeated 5 times.

[0056] Thereafter, the sample was dried at 150° C. for 1.5 hours and left to stand for 24 hours, after which the capacitance and the dielectric loss tangent were measured. The number of samples was 20.

[0057] These results are shown in Table 1 below.

[0058] Comparative Example 1 <Preparation of Conductive Material> As shown in Table 1, conductive materials in a sol state were prepared in the same manner as in the Examples, except that the ratio of silver nitrate to copper (II) nitrate trihydrate was changed.

[0059] <Coating and Firing> The conductive material was coated, dried and fired in the same manner as in the example.

[0060] <Structural Analysis of External Electrodes> As in the case of the examples, structural analysis of the external electrodes was carried out.

[0061] As a result, the STEM image shown in Fig. 7 and the EDX images shown in Fig. 8 to Fig. 10 were obtained. Fig. 9 is an image in which the Ag region in the EDX image shown in Fig. 8 is emphasized, and Fig. 10 is an image in which the Cu region in the EDX image shown in Fig. 8 is emphasized.

[0062] In Figures 7 to 10, representative silver particles 11 and copper particles 12 are denoted by reference numerals "11" and "12," respectively.

[0063] As shown in FIGS. 7 to 10, in Comparative Example 1, the growth of flat particles did not progress as much as in the Examples.

[0064] <Plating> Plating was carried out in the same manner as in the example.

[0065] <Evaluation of Bonding Between Internal and External Electrodes> Evaluation was carried out in the same manner as in the Examples, and the results are shown in Table 1 below.

[0066] Comparative Example 2 <Preparation of Conductive Material> As shown in Table 1, a conductive material in a sol state was prepared in the same manner as in the example, except that silver nitrate was not included.

[0067] <Coating and Firing> The conductive material was coated, dried and fired in the same manner as in the example.

[0068] <Structural Analysis of External Electrodes> As in the case of the examples, structural analysis of the external electrodes was carried out.

[0069] As a result, the STEM image shown in Figure 11 and the EDX image shown in Figure 12 were obtained. In Figures 11 and 12, representative copper particles 12 are each designated by the reference symbol "12".

[0070] As shown in FIGS. 11 and 12, in Comparative Example 2, the growth of flat particles did not progress as much as in the Example.

[0071] <Plating> Plating was carried out in the same manner as in the example.

[0072] <Evaluation of Bonding Between Internal and External Electrodes> Evaluation was carried out in the same manner as in the Examples. The results are shown in Table 1.

[0073]

[0074] In the Examples, the capacitance variation coefficient before and after 0 Ω discharge, the dielectric loss tangent before and after 0 Ω discharge, and the dielectric loss tangent variation coefficient before and after 0 Ω discharge were smaller than those in Comparative Examples 1 and 2. This indicates that the Examples have good contact between the external electrode and the internal electrode and good conductivity within the external electrode. This is presumably because, in the sol-state conductive material, metal salts that precipitate silver or copper upon heat treatment are dissolved, and the volume of the silver salt after conversion to metallic silver is made larger than the volume of the copper salt after conversion to metallic copper. By doing so, copper is sufficiently diffused into the internal electrode upon firing, while silver does not diffuse. As shown in FIGS. 3 to 6 , silver particles 11 are partially bonded to copper particles 12 to form flattened bonded particles 13, making the particles more likely to come into contact with each other. Furthermore, the presence of the flattened bonded particles 13 achieves good plating adhesion.

[0075] In contrast, in Comparative Example 1, the coefficients of variation of the dielectric loss tangent before and after 0 Ω discharge and the dielectric loss tangent after 0 Ω discharge were larger than those in Examples. This is presumably because, in the conductive material for forming the external electrode, the volume of the silver salt after it has been converted into metallic silver is smaller than the volume of the copper salt after it has been converted into metallic copper, and therefore, as shown in Figures 7 to 10, the growth of flat joined particles in which silver particles and copper particles are joined together is difficult, resulting in insufficient conductivity within the external electrode.

[0076] Furthermore, in Comparative Example 2, the coefficient of variation of the dielectric loss tangent before 0Ω discharge and the dielectric loss tangent after 0Ω discharge were larger than those in the Examples. This is presumably because the conductive material for forming the external electrodes did not contain silver salt, and therefore flat particles did not grow, as shown in Figures 11 and 12, and the conductivity within the external electrodes was insufficient.

[0077] The embodiments of the present invention include the following:

[0078] <1> A multilayer ceramic electronic component comprising: a ceramic body having a plurality of laminated ceramic layers and internal electrodes arranged along interfaces between the ceramic layers; and external electrodes provided on surfaces of the ceramic body and electrically connected to the internal electrodes, wherein the external electrodes include glass containing a conductive metal and silicon, the conductive metal includes silver and copper, wherein the silver component exceeds the copper component by volume, and the silver and the copper are present in the form of silver particles, copper particles, and joined particles in which silver particles and copper particles are joined together, the joined particles are flat, and copper is not present on surfaces of the silver particles and silver is not present on surfaces of the copper particles other than at joint surfaces between the silver particles and the copper particles in the joined particles, and a portion of the copper contained in the external electrodes is diffused into the internal electrodes.

[0079] <2> The multilayer ceramic electronic component according to <1>, wherein the internal electrodes contain nickel as a conductive component.

[0080] <3> The multilayer ceramic electronic component according to <1> or <2>, which is a multilayer ceramic capacitor.

[0081] <4> A conductive material in a sol state, comprising: a conductive metal salt that becomes a conductive metal as a conductive component when fired; a glass frit that contains a metal salt for glass and becomes a silicon-containing glass when fired; and a solvent that dissolves or disperses the conductive metal salt and the glass frit, wherein a ratio of the content of the glass frit to the content of the conductive metal salt is 0.04 or more and 1.40 or less, converted into a mass of the conductive metal salt after metallization and a mass of the glass frit after vitrification; the conductive metal salt comprises a silver salt and a copper salt; and a ratio of a volume of the silver salt after metallization to a volume of the copper salt after metallization exceeds 1.

[0082] <5> The conductive material according to <4>, wherein the solvent has a boiling point of 145°C or less.

[0083] <6> The conductive material according to <5>, wherein the solvent contains 2-methoxyethanol.

[0084] <7> The conductive material according to any one of <4> to <6>, wherein the silver salt includes one of a silver carboxylate and a silver nitrate, and the copper salt includes one of a copper carboxylate and a copper nitrate.

[0085] <8> The conductive material according to any one of <4> to <7>, further comprising an organic binder.

[0086] <9> The conductive material according to <8>, wherein the organic binder contains hydroxypropyl cellulose.

[0087] <10> A method for manufacturing a multilayer ceramic electronic component including a ceramic body having a plurality of laminated ceramic layers and internal electrodes arranged along interfaces between the ceramic layers, and external electrodes provided on surfaces of the ceramic body and electrically connected to the internal electrodes, the method comprising: applying the conductive material according to any one of <4> to <9> to the surface of the ceramic body so as to be in contact with the internal electrodes; heating and drying the applied conductive material at a temperature of 145°C or higher; and then firing the conductive material to form the external electrodes.

[0088] <11> The method for manufacturing a multilayer ceramic electronic component according to <10>, further comprising the step of forming a plating film on the external electrodes.

[0089] REFERENCE SIGNS LIST 1 Multilayer ceramic capacitor 2 Ceramic element 3 Ceramic layer 4, 5 Internal electrodes 6, 7 External electrodes 8 Plating film 11 Silver particles 12 Copper particles 13 Bonding particles

Claims

1. A ceramic element having a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers, external electrodes provided on the surface of the ceramic element and electrically connected to the internal electrodes, comprising: The external electrodes include a conductive metal and a glass containing silicon, The conductive metal includes silver and copper. In terms of volume ratio, the silver component is more than the copper component. The silver and the copper exist in the states of silver particles, copper particles, and joined particles in which silver particles and copper particles are joined, The joined particles are flat, Except for the joined surfaces of the silver particles and the copper particles in the joined particles, copper does not exist on the surface of the silver particles, and silver does not exist on the surface of the copper particles, A part of the copper contained in the external electrodes has diffused into the internal electrodes, A multilayer ceramic electronic component.

2. The multilayer ceramic electronic component according to claim 1, wherein the internal electrodes contain nickel as a conductive component.

3. The multilayer ceramic electronic component according to claim 1, wherein the multilayer ceramic electronic component is a multilayer ceramic capacitor.

4. A conductive metal salt that becomes a conductive metal as a conductive component by firing, a glass raw material that contains a metal salt for glass and becomes a glass containing silicon by firing, and a solvent that dissolves or disperses the conductive metal salt and the glass raw material, The ratio of the content of the glass raw material to the content of the conductive metal salt is 0.04 or more and 1.40 or less when converted to the mass after metallization of the conductive metal salt and the mass after vitrification of the glass raw material, The conductive metal salts include silver salts and copper salts, The ratio of the volume after silver metallization of the silver salt to the volume after copper metallization of the copper salt exceeds 1, A conductive material in a sol state.

5. The conductive material according to claim 4, wherein the solvent has a boiling point of 145 °C or lower.

6. The conductive material according to claim 5, wherein the solvent contains 2-methoxyethanol.

7. The conductive material according to claim 4, wherein the silver salt contains either silver carboxylate or silver nitrate, and the copper salt contains either copper carboxylate or copper nitrate.

8. The conductive material according to claim 4, further comprising an organic binder.

9. The conductive material according to claim 8, wherein the organic binder contains hydroxypropyl cellulose.

10. A ceramic body having a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers, and an external electrode provided on the surface of the ceramic body and electrically connected to the internal electrodes, and a method for manufacturing a multilayer ceramic electronic component comprising: Applying the conductive material according to any one of claims 4 to 9 to the surface of the ceramic body so as to contact the internal electrode; Heating and drying the applied conductive material at a temperature of 145°C or higher; Subsequently, firing the conductive material to form the external electrode; A method for manufacturing a multilayer ceramic electronic component, comprising:

11. The method for manufacturing a multilayer ceramic electronic component according to claim 10, further comprising a step of forming a plating film on the external electrode.