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

Abstract

Provided is a laminated ceramic electronic component having excellent contact with an internal electrode disposed inside a ceramic body while improving the conductivity of an external electrode provided on the surface of the ceramic body. The external electrode includes a conductive metal and a silicon-containing glass, the conductive metal includes silver and copper, the silver component is more than the copper component in volume ratio, and the silver and the copper are present in each state of silver particles (11), copper particles (12), and bonding particles (13) in which the silver particles (11) and the copper particles (12) are bonded. The bonding particles (13) have a flat shape, and no copper is present on the surface of the silver particles (11) and no silver is present on the surface of the copper particles (12) except for the bonding surfaces of the silver particles (11) and the copper particles (12) in the bonding particles (13). A portion of the copper contained in the external electrode diffuses into the internal electrode.

Description

Technical Field

[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 particularly relates to a structure of an external electrode provided on the surface of a ceramic body included in a multilayer ceramic electronic component, a conductive material for forming the external electrode, and a method for manufacturing a multilayer ceramic electronic component using the conductive material. Background Art

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

[0003] The metal oxide film precipitates metal through reduction heat treatment. This metal becomes a base metal film for ensuring contact with the internal electrode. The base metal film is a membranous aggregate in which many metal particles are attached to each other microscopically. Since the particle diameter of the metal particles is about 0.1 to 1 μm, the thickness of the base metal film is 0.1 to 1.0 μm on any coated surface. The material of the metal particles is, for example, Cu, Ni, W, Mo, Nb, Ta, Ti, or Zr.

[0004] To form the base metal film, for example, a solution obtained by mixing a CuO coating solution and an ITO coating solution in a ratio of 7:3 can be used. This solution is heat-treated at 480°C for 40 minutes in air to oxidize the metal compound, and then heat-treated at 450°C for 40 minutes in a reducing atmosphere to reduce a part of the metal oxide.

[0005] In the technology described in Patent Document 1, in order to prevent the plating solution from infiltrating through the base metal film, a sealing metal film having a higher density than the base metal film is formed. The material of the sealing metal film is, for example, Cu, Ni, W, Mo, Nb, Ta, Ti, or Zr. The sealing metal film is preferably thicker than the base metal film, and thus can be formed by a sputtering method, an evaporation method, a CVD method, etc. that can easily control the film thickness.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent No. 6056388 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In the technology described in Patent Document 1, it is speculated that the base metal layer contains ITO and CuO that remains partially as a result of the reduction and precipitation of Cu. Therefore, since the base metal layer has many inter-particle gaps and low density, it is considered to have poor conductivity and insufficient sealing properties against plating solutions and water vapor. The formation of a sealing metal film as a countermeasure for the sealing property not only becomes an obstacle to the thinning of the external electrode but also increases the number of processes.

[0011] In addition, for the material described in Patent Document 1 and a film with a thickness of 0.1 to 1.0 μm obtained by applying heat treatment, it is considered that the contact property with the internal electrode containing a conductive component such as Ni is insufficient.

[0012] Accordingly, an object of the present invention is to provide a multilayer ceramic electronic component capable of improving the conductivity of an external electrode provided on the surface of a ceramic body and having excellent contact property with an internal electrode disposed inside the ceramic body, and to provide a conductive material for forming the external electrode and a method for manufacturing a multilayer ceramic electronic component using the conductive material.

[0013] Technical Solution for Solving the Problem

[0014] In the present invention, in order to solve the above technical problems, the structure of the external electrode in the multilayer ceramic electronic component is improved. In addition, a conductive material for forming such an improved external electrode and a method for manufacturing a multilayer ceramic electronic component using the conductive material are provided.

[0015] The ceramic electronic component according to the present invention includes: a ceramic body having a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes.

[0016] The external electrode contains a conductive metal and a glass containing silicon. The conductive metal contains silver and copper. By volume ratio, the silver component is more than the copper component. Silver and 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 surface of the silver particles and copper particles in the joined particles, there is no copper on the surface of the silver particles, and there is no silver on the surface of the copper particles. Moreover, a part of the copper contained in the external electrode diffuses into the internal electrode.

[0017] The conductive material involved in the present invention is in a sol state and includes: a conductive metal salt that becomes a conductive metal as a conductive component through firing; a glass raw material that includes a metal salt for glass and becomes a glass containing silicon through 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, in terms of the mass after metallization of the conductive metal salt and the mass after vitrification of the glass raw material, is 0.04 or more and 1.40 or less. The conductive metal salt includes a silver salt and a copper salt, and the ratio of the volume of the metal silver after silver metallization of the silver salt to the volume of the metal copper after copper metallization of the copper salt exceeds 1.

[0018] The method for manufacturing a multilayer ceramic electronic component according to the present invention is a method for manufacturing a multilayer ceramic electronic component. The multilayer ceramic electronic component includes: a ceramic body having a plurality of laminated ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes. The method for manufacturing a multilayer ceramic electronic component is characterized by including: a step of applying the above-mentioned conductive material according to the present invention to the surface of the above-mentioned ceramic body so as to be in contact with the above-mentioned internal electrodes; a step of heating and drying the applied conductive material at a temperature of 145°C or higher; and a step of firing the conductive material next to form the external electrodes.

[0019] Advantages of the Invention

[0020] In the multilayer ceramic electronic component according to the present invention, since a part of the copper in the external electrode diffuses into the internal electrode, good contact can be obtained between the external electrode and the internal electrode. In addition, in the external electrode, silver does not diffuse into the internal electrode, and a part of the silver particles is joined to the copper particles to form flat joined particles, resulting in a state where the particles are easily in contact with each other. Therefore, good conductivity and good plating adhesion can be achieved within the external electrode.

[0021] In the conductive material according to the present invention, since silver is contained in a larger amount than copper by volume ratio, flat joined particles formed by the joining of silver particles and copper particles are easily generated during firing. Therefore, a state where the particles are easily in contact with each other can be obtained, and good conductivity can be obtained in a conductor film such as the external electrode formed of this conductive material. In addition, since the conductive material is in a sol state, as the gelation and vitrification based on heat treatment progress, the solvent and reaction by-products are removed, so volume shrinkage occurs in the thickness direction in a conductor film such as the external electrode formed of this conductive material, which is advantageous for thinning the conductor film.

[0022] According to the manufacturing method of the multilayer ceramic electronic component of the present invention, by heating and drying the above conductive material at a temperature of 145°C or higher, silver particles can be precipitated before firing, so that the silver particles can grow before the bonding of silver particles and copper particles in the firing process. This is beneficial to the growth of flat bonding particles and the formation of a thinned external electrode. Description of the Drawings

[0023] Figure 1 FIG. is a cross-sectional view schematically showing a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to an embodiment of the present invention.

[0024] Figure 2 is Figure 1 A cross-sectional view schematically showing an enlarged portion of the multilayer ceramic capacitor 1 provided with an external electrode 6.

[0025] Figure 3 FIG. is a diagram showing a STEM image of a cross-section of an external electrode of a multilayer ceramic capacitor related to an example fabricated in an experimental example.

[0026] Figure 4 is a diagram showing Figure 3 An EDX image of a cross-section of the external electrode shown.

[0027] Figure 5 is Figure 4 A diagram emphasizing the Ag region in the EDX image shown.

[0028] Figure 6 is Figure 4 A diagram emphasizing the Cu region in the EDX image shown.

[0029] Figure 7 FIG. is a diagram showing a STEM image of a cross-section of an external electrode of a multilayer ceramic capacitor related to Comparative Example 1 fabricated in an experimental example.

[0030] Figure 8 is a diagram showing Figure 7 An EDX image of a cross-section of the external electrode shown.

[0031] Figure 9 is Figure 8 A diagram emphasizing the Ag region in the EDX image shown.

[0032] Figure 10 is Figure 8 A diagram emphasizing the Cu region in the EDX image shown.

[0033] Figure 11 FIG. is a diagram showing a STEM image of a cross-section of an external electrode of a multilayer ceramic capacitor related to Comparative Example 2 fabricated in an experimental example.

[0034] Figure 12 is a view showing Figure 11 an EDX image of a cross-section of the external electrodes shown. DETAILED DESCRIPTION

[0035] Referring Figure 1 to, the structure of a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to an embodiment of the present invention will be described.

[0036] 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 disposed 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 that are alternately disposed in the stacking direction of the ceramic body 2. On the surface of the ceramic body 2, more specifically, on opposite end faces, a first external electrode 6 and a second external electrode 7 are provided, respectively. 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.

[0037] The ceramic layer 3 includes, for example, a dielectric ceramic having ABO3 (where A is at least one of Ba, Ca, and Sr, and B is at least one of Ti and Zr) as a main component. In addition, the dielectric ceramic may have the above ABO3 as a main component and contain at least one of Mn, Mg, Si, Y, Dy, and Gd as a sub-component.

[0038] The internal electrodes 4 and 5 preferably contain a conductive metal or an alloy containing a conductive metal. For example, it is preferable to contain one selected from nickel, copper, silver, and a silver / palladium alloy, and particularly preferably contain nickel as a conductive component.

[0039] The external electrodes 6 and 7 are formed by applying a conductive material described later to the end faces of the ceramic body 2 so as to be in contact with the respective end portions of the internal electrodes 4 and 5 and firing them. In Figure 2 a partial cross-sectional view of the first external electrode 6 is shown. In addition, although the second external electrode 7 is not shown in Figure 2 , it has substantially the same structure as the first external electrode 6. Therefore, only the first external electrode 6 will be described, and the description of the second external electrode 7 may be omitted. A plating film 8 is formed on the external electrodes 6 and 7 (omitted from the illustration in Figure 1 ).

[0040] The external electrodes 6 and 7 contain a conductive metal and a glass containing silicon. The conductive metal contains silver and copper, and the silver component is more than the copper component by volume ratio. The structure of the external electrodes 6 and 7 will be described with reference to a view of a cross-section of the external electrodes of a multilayer ceramic capacitor manufactured in an experimental example described later. Figure 3It is a diagram showing a STEM image of a cross-section of an external electrode. Figure 4 It is a diagram showing Figure 3 an EDX image of a cross-section of the external electrode shown. In addition, Figure 5 it is a diagram Figure 4 in which the Ag region is emphasized in the EDX image shown, Figure 6 and it is a diagram Figure 4 in which the Cu region is emphasized in the EDX image shown.

[0041] In particular, in Figure 4 the silver particles 11 appear as white granular regions, and the copper particles 12 appear as gray granular regions. In addition, in Figure 5 the regions where the silver particles 11 exist are emphasized more whitely, and in Figure 6 the regions where the copper particles 12 exist are emphasized more whitely.

[0042] Referring to Figures 3 to 6 , in the external electrode, silver and copper exist in the respective states of silver particles 11, copper particles 12, and joined particles 13 where the silver particles 11 and the copper particles 12 are joined. The joined particles 13 are flat. Outside the joined surfaces of the silver particles 11 and the copper particles 12 in the joined particles 13, there is no copper on the surface of the silver particles 11, and there is no silver on the surface of the copper particles 12.

[0043] Although not shown in Figures 3 to 6 , as schematically shown in Figure 2 , a part of the copper contained in the external electrode 6 diffuses into the internal electrode 4. In this way, a part of the copper in the external electrodes 6 and 7 diffuses into the internal electrodes 4 and 5, so that good contact can be obtained between the external electrodes 6 and 7 and the internal electrodes 4 and 5.

[0044] In addition, in the external electrodes 6 and 7, silver does not diffuse into the internal electrodes 4 and 5. As described above, a part of the silver particles 11 is joined to the copper particles 12 to form flat joined particles 13, resulting in a state where the particles are easily in contact with each other. Therefore, good conductivity and good plating adhesion can be achieved within the external electrodes 6 and 7.

[0045] The multilayer ceramic capacitor 1 is manufactured, for example, through the following process. First, a ceramic slurry containing raw material powder of ceramic having the above-described composition is prepared. Next, an appropriate sheet forming method is applied to the ceramic slurry to form a green ceramic sheet. Next, on a given green ceramic sheet among a plurality of green ceramic sheets, conductive pastes to be the internal electrodes 4 and 5 are applied by printing or the like. Next, the plurality of green ceramic sheets are stacked and then pressed to obtain an unprocessed ceramic body. Next, the unprocessed ceramic body is fired. In this firing process, the green ceramic sheet becomes the ceramic layer 3. Thereafter, a process of forming the external electrodes 6 and 7 on the end faces of the ceramic body 2 is performed, and next, a process of forming the plating films 8 on the external electrodes 6 and 7 is performed.

[0046] The conductive material for forming the external electrodes 6 and 7 contains a conductive metal salt that becomes a conductive metal as a conductive component through firing, a glass raw material containing a glass metal salt and becoming a silicon-containing glass through 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, in terms of the metallized mass of the conductive metal salt and the vitrified mass of the glass raw material, is 0.04 or more and 1.40 or less. The above-described conductive metal salt contains a silver salt and a copper salt, and the ratio of the volume of the metal silver after silver metallization of the silver salt to the volume of the metal copper after copper metallization of the copper salt exceeds 1.

[0047] Such a conductive material is initially in a sol state and is applied to the opposing end faces of the ceramic body 2. Next, after being set to a gel state through heat drying, it is fired at a temperature equal to or higher than the softening point and lower than the melting point of the above-described glass raw material, and the glass raw material is vitrified.

[0048] In the above heat drying process, a temperature of 145°C or higher is applied. Accordingly, silver particles can be precipitated before firing, and thus the silver particles can grow before the joining of the silver particles and the copper particles in the firing process. This is advantageous for the growth of flat joining particles and the formation of a thin-film external electrode.

[0049] In the heat drying process, since a temperature of 145°C or higher is applied, the solvent contained in the conductive material preferably has a boiling point of 145°C or lower. As the solvent, for example, 2-methoxyethanol can be advantageously used.

[0050] In addition, according to the above conductive material, since silver is contained more than copper by volume ratio, flat bonding particles 13 formed by the bonding of silver particles 11 and copper particles 12 are likely to be generated during firing. Therefore, a state where particles are easily in contact with each other can be obtained, and good conductivity can be achieved in the external electrodes 6 and 7 formed of this conductive material. In addition, the conductive material is initially in a sol state. As gelation and vitrification based on heat treatment progress, the solvent and reaction by-products are removed. Therefore, in the external electrodes 6 and 7 formed of this conductive material, volume shrinkage occurs in the thickness direction, which is advantageous for thinning.

[0051] The glass raw material contained in the above conductive material preferably contains nano-silica and boric acid in addition to the above metal salts for glass.

[0052] The metal salts for glass as the glass raw material include, for example, lithium nitrate and sodium nitrate.

[0053] The silver salt contained in the conductive material includes, for example, any one of silver carboxylate and silver nitrate, and the copper salt includes, for example, any one of copper carboxylate and copper nitrate.

[0054] In order to adjust the viscosity, etc., the conductive material may also contain an organic binder. As the organic binder, for example, hydroxypropyl cellulose is advantageously used.

[0055] Although the plating films 8 formed on the external electrodes 6 and 7 are not shown in detail, they are composed of, for example, a Cu plating layer, an Ni plating layer thereon, and an Sn plating layer thereon.

[0056] As described above, the present invention has been described in relation to the external electrodes of the multilayer ceramic capacitor. However, if it is a multilayer ceramic electronic component having a multilayer ceramic body with a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers, and external electrodes electrically connected to the internal electrodes are provided on the surface of the ceramic body, the present invention can also be applied to multilayer ceramic electronic components other than the multilayer ceramic capacitor.

[0057] Next, experimental examples implemented to confirm the effects of the present invention will be described.

[0058] [Examples]

[0059] [Production of Conductive Material]

[0060] A sol-state conductive material containing the following (1) to (8) was produced.

[0061] (1) Tetraethoxysilane: 2.23% by mass,

[0062] (2) Boric acid: 0.38% by mass,

[0063] (3) Lithium nitrate (melting point: 260 °C): 0.20 mass%,

[0064] (4) Sodium nitrate (melting point: 306 °C): 0.27 mass%,

[0065] (5) Silver nitrate: 7.60 mass%,

[0066] (6) Copper(II) nitrate trihydrate: 11.02 mass%,

[0067] (7) Hydroxypropyl cellulose (2.0 - 2.9 @ 20 °C / 2% aqueous solution): 11.60 mass%,

[0068] (8) 2-Methoxyethanol: 54.71 mass%.

[0069] The above (1) - (4) are glass raw materials that become glass through firing. (3) and (4) are metal salts for glass. (5) is a silver salt that becomes silver through firing. (6) is a copper salt that becomes copper through firing. (7) is an organic binder. (8) is a solvent.

[0070] In addition, the composition of the conductive material related to the example is also shown in Table 1 described later.

[0071] <Coating / Firing>

[0072] After dipping the end faces of the ceramic body of a multilayer ceramic capacitor (0.6 mm × 0.3 mm × 0.3 mm) having a Ni internal electrode into the above conductive material in a sol state, the conductive material was dried at 150 °C for 10 minutes to gel. The opposite end faces of the ceramic body were also dipped and dried in the same manner.

[0073] Next, hydrogen was introduced into N2, and firing was performed at 700 °C, which is above the softening point and below the melting point of the glass raw material, to form an external electrode.

[0074] <Structural Analysis of External Electrode>

[0075] At the center of the surfaces of the multilayer ceramic capacitor that extend in the width direction and the thickness direction, for the external electrode that becomes the specimen, structural analysis was performed using STEM (manufactured by Hitachi High-Technologies: scanning electron microscope "HD-2300A") and EDX (manufactured by EDAX: energy-dispersive X-ray spectrometer "Genesis XM4"). As a result, the Figure 3 shown STEM image, and the Figures 4 to 6 shown EDX image were obtained. In addition, Figure 5 is a diagram in which the Ag region is emphasized in the Figure 4 shown EDX image, and Figure 6 is inFigure 4 A figure emphasizing the Cu region in the EDX image shown.

[0076] In Figures 3 to 6 reference numerals "11", "12", and "13" are respectively assigned to representative particles of the silver particles 11, the copper particles 12, and the joint particles 13 where the silver particles 11 and the copper particles 12 are joined.

[0077] As Figures 3 to 6 shown, flat joint particles 13 where the silver particles 11 and the copper particles 12 are joined were confirmed. Further, it was confirmed that there is no copper on the surface of the silver particles 11 and no silver on the surface of the copper particles 12, except for the joint surfaces of the silver particles 11 and the copper particles 12 in the joint particles 13.

[0078] <Plating>

[0079] For the external electrodes, electrolytic Cu, Ni, and Sn plating was successively performed based on the following conditions to form a plating film.

[0080] (Cu plating conditions)

[0081] · Plating bath type: Pyrophosphate Cu plating bath (pH = 8.6),

[0082] · Bath temperature: 55°C,

[0083] · Current value: 10 A,

[0084] · Plating time: 90 minutes.

[0085] (Ni plating conditions)

[0086] · Plating bath type: Watts bath (pH = 4.0),

[0087] · Bath temperature: 60°C,

[0088] · Current value: 6 A,

[0089] · Plating time: 51 minutes.

[0090] (Sn plating conditions)

[0091] · Plating bath type: Neutral plating bath (pH = 6.0),

[0092] · Bath temperature: 25°C,

[0093] · Current value: 3 A,

[0094] · Plating time: 66 minutes.

[0095] <Evaluation of the bondability between the internal electrode and the external electrode>

[0096] The obtained multilayer ceramic capacitor specimens were dried at 150 °C for 1.5 hours. After standing for 24 hours, the capacitance and the tangent of the loss angle were measured.

[0097] Next, a voltage of 25 V was applied to each specimen for 5 seconds, and then the specimen was discharged by dropping it onto a stainless-steel plate (0 Ω discharge). This was repeated 5 times.

[0098] After that, they were dried at 150 °C for 1.5 hours. After standing for 24 hours, the capacitance and the tangent of the loss angle were measured. In addition, the number of specimens was set to 20.

[0099] The results are shown in Table 1 described below.

[0100] [Comparative Example 1]

[0101] [Fabrication of Conductive Material]

[0102] As shown in Table 1, a conductive material in a sol state was fabricated in the same manner as in the example, except that the ratio of silver nitrate and copper(II) nitrate trihydrate was changed.

[0103] [Coating / Firing]

[0104] The conductive material was coated, dried, and fired in the same manner as in the example.

[0105] [Structural Analysis of External Electrodes]

[0106] The structural analysis of the external electrodes was performed in the same manner as in the example.

[0107] As a result, STEM images shown in Figure 7 and EDX images shown in Figures 8 to 10 were obtained. In addition, Figure 9 is a figure in which the Ag region is emphasized in the EDX image shown in Figure 8 and Figure 10 is a figure in which the Cu region is emphasized in the EDX image shown in Figure 8 Reference numerals "11" and "12" were respectively assigned to representative particles of silver particles 11 and copper particles 12 in

[0108] As shown in Figures 7 to 10 , in Comparative Example 1, the growth of flat-shaped particles did not progress compared to the example.

[0109] As Figures 7 to 10 shows, in Comparative Example 1, the growth of flat-shaped particles did not progress compared to the example.

[0110] [Plating]

[0111] Plating was performed in the same manner as in the example.

[0112] <Evaluation of Bonding Property between Internal Electrode and External Electrode>

[0113] Similar to the case of the examples, the evaluation was conducted. The results are shown in Table 1 described later.

[0114] [Comparative Example 2]

[0115] <Production of Conductive Material>

[0116] As shown in Table 1, a conductive material in a sol state was produced in the same manner as in the examples except that silver nitrate was not included.

[0117] <Coating / Firing>

[0118] Similar to the case of the examples, the conductive material was coated, dried, and fired.

[0119] <Structural Analysis of External Electrode>

[0120] Similar to the case of the examples, the structural analysis of the external electrode was conducted.

[0121] As a result, the Figure 11 shown STEM image and Figure 12 the Figure 11 shown EDX image were obtained. In Figure 12 and

[0122] As Figure 11 and Figure 12 shown, in Comparative Example 2, the growth of flat particles did not progress compared to the examples.

[0123] <Plating>

[0124] Similar to the case of the examples, plating was conducted.

[0125] <Evaluation of Bonding Property between Internal Electrode and External Electrode>

[0126] Similar to the case of the examples, the evaluation was conducted. The results are shown in Table 1.

[0127] [Table 1]

[0128] Table 1

[0129]

[0130] In an embodiment, the coefficient of change in electrostatic capacitance before and after 0 Ω discharge, the tangent of the dielectric loss angle before and after 0 Ω discharge, and the coefficient of change in the tangent of the dielectric loss angle before and after 0 Ω discharge show smaller values compared to those of Comparative Examples 1 and 2. From this, it can be known that in the embodiment, there is good contact between the external electrode and the internal electrode, and good conductivity within the external electrode. It is speculated that this is because in the conductive material in a sol state, the metal salts that precipitate silver and copper are dissolved in advance by heat treatment, and the volume after the metallization of silver salt is larger than the volume after the metallization of copper salt. Thus, by firing, copper diffuses sufficiently into the internal electrode, while silver does not diffuse. As Figures 3 to 6 shown, a part of the silver particles 11 is joined to the copper particles 12 to form flat joined particles 13, resulting in a state where the particles are easily in contact with each other. In addition, the presence of the flat joined particles 13 enables good plating adhesion.

[0131] In contrast, in Comparative Example 1, the coefficient of change in the tangent of the dielectric loss angle before and after 0 Ω discharge and the tangent of the dielectric loss angle after 0 Ω discharge show larger values than those in the embodiment. It is speculated that this is because in the conductive material used to form the external electrode, since the volume after the metallization of silver salt is smaller than the volume after the metallization of copper salt, as Figures 7 to 10 shown, the growth of flat joined particles where silver particles and copper particles are joined does not easily progress, and the conductivity within the external electrode is insufficient.

[0132] In addition, in Comparative Example 2, the coefficient of change in the tangent of the dielectric loss angle before 0 Ω discharge and the tangent of the dielectric loss angle after 0 Ω discharge show larger values than those in the embodiment. It is speculated that this is because in the conductive material used to form the external electrode, since it does not contain silver salt, as Figure 11 and Figure 12 shown, the growth of flat particles does not occur, and the conductivity within the external electrode is insufficient.

[0133] In an embodiment of the present invention, there is the following mode.

[0134] <1>

[0135] A multilayer ceramic electronic component, comprising:

[0136] A ceramic body having a plurality of laminated ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and

[0137] An external electrode provided on the surface of the ceramic body and electrically connected to the internal electrode,

[0138] The external electrode includes a conductive metal and a glass containing silicon,

[0139] The conductive metal includes silver and copper. By 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 formed by the joining of silver particles and copper particles.

[0140] The joined particles are flat.

[0141] Except for the joining surface of the silver particles and the copper particles in the joined particles, there is no copper on the surface of the silver particles, and there is no silver on the surface of the copper particles.

[0142] A part of the copper included in the external electrode diffuses into the internal electrode.

[0143] <2>

[0144] In the multilayer ceramic electronic component described in <1>, the internal electrode includes nickel as a conductive component.

[0145] <3>

[0146] In the multilayer ceramic electronic component described in <1> or <2>, the multilayer ceramic electronic component is a multilayer ceramic capacitor.

[0147] <4>

[0148] A conductive material in a sol state includes:

[0149] A conductive metal salt that becomes a conductive metal as a conductive component through firing;

[0150] A glass raw material that includes a glass metal salt and becomes a glass containing silicon through firing; and

[0151] A solvent that dissolves or disperses the conductive metal salt and the glass raw material.

[0152] The ratio of the content of the glass raw material to the content of the conductive metal salt, in terms of the metallized mass of the conductive metal salt and the vitrified mass of the glass raw material, is 0.04 or more and 1.40 or less.

[0153] The conductive metal salt includes a silver salt and a copper salt.

[0154] The ratio of the volume of the metallized silver of the silver salt to the volume of the metallized copper of the copper salt exceeds 1.

[0155] <5>

[0156] In the conductive material described in <4>, the solvent has a boiling point of 145 °C or lower.

[0157] <6>

[0158] In the conductive material described in <5>, the solvent contains 2-methoxyethanol.

[0159] <7>

[0160] In the conductive material described in any one of <4> to <6>, the silver salt contains either silver carboxylate or silver nitrate, and the copper salt contains either copper carboxylate or copper nitrate.

[0161] <8>

[0162] In the conductive material described in any one of <4> to <7>, the conductive material further contains an organic binder.

[0163] <9>

[0164] In the conductive material described in <8>, the organic binder contains hydroxypropyl cellulose.

[0165] <10>

[0166] A method for manufacturing a multilayer ceramic electronic component, which is a method for manufacturing a multilayer ceramic electronic component,

[0167] The multilayer ceramic electronic component includes: a ceramic body having a plurality of laminated ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes.

[0168] Among them, the method for manufacturing the multilayer ceramic electronic component includes:

[0169] A step of applying the conductive material described in any one of <4> to <9> to the surface of the ceramic body so as to be in contact with the internal electrodes;

[0170] A step of heating and drying the applied conductive material at a temperature of 145 °C or higher; and

[0171] Next, a step of firing the conductive material to form the external electrodes.

[0172] <11>

[0173] In the method for manufacturing a multilayer ceramic electronic component described in <10>, it further includes: a step of forming a plating film on the external electrodes.

[0174] Description of Reference Numerals

[0175] 1 Multilayer ceramic capacitor

[0176] 2 Ceramic body

[0177] 3 Ceramic layer

[0178] 4, 5 Inner electrodes

[0179] 6, 7 Outer electrodes

[0180] 8 Coating film

[0181] 11 Silver particles

[0182] 12 Copper particles

[0183] 13 Bonding particles.

Claims

1. A multilayer ceramic electronic component, comprising: a ceramic body having a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes, wherein the external electrodes include a conductive metal and a glass containing silicon, the conductive metal includes silver and copper, and in terms of volume ratio, the silver component is more than the copper component, and the silver and the copper exist in the states of silver particles, copper particles, and joined particles in which the silver particles and the 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, there is no copper on the surface of the silver particles and no silver on the surface of the copper particles, a part of the copper contained in the external electrodes diffuses into the internal electrodes.

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

3. The multilayer ceramic electronic component according to claim 1 or 2, wherein the multilayer ceramic electronic component is a multilayer ceramic capacitor.

4. A conductive material in a sol state, comprising: a conductive metal salt that becomes a conductive metal as a conductive component through firing; a glass raw material containing a glass metal salt that becomes a glass containing silicon through 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, in terms of the metallized mass of the conductive metal salt and the vitrified mass of the glass raw material, is 0.04 or more and 1.40 or less, the conductive metal salt includes a silver salt and a copper salt, the ratio of the volume of the metal silver after silver metallization of the silver salt to the volume of the metal copper after copper metallization of the copper salt exceeds 1.

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 any one of claims 4 to 6, wherein the silver salt includes either silver carboxylate or silver nitrate, and the copper salt includes either copper carboxylate or copper nitrate.

8. The conductive material according to any one of claims 4 to 7, wherein the conductive material further includes an organic binder.

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

10. A method for manufacturing a multilayer ceramic electronic component, which is a method for manufacturing a multilayer ceramic electronic component, The stacked ceramic electronic component includes: a ceramic body having a plurality of stacked ceramic layers and internal electrodes disposed along the interfaces between the ceramic layers; and external electrodes provided on the surface of the ceramic body and electrically connected to the internal electrodes, wherein the method for manufacturing the multilayer ceramic electronic component includes: a step of applying the conductive material according to any one of claims 4 to 9 to the surface of the ceramic body so as to be in contact with the internal electrodes; a step of heating and drying the applied conductive material at a temperature of 145°C or higher; and subsequently, a step of firing the conductive material to form the external electrodes.

11. The manufacturing method of the multilayer ceramic electronic component according to claim 10, wherein, It further includes: A step of forming a plating film on the external electrode.

Images