Multilayer ceramic electronic components

Abstract

To provide a multilayer ceramic electronic component having high reliability.SOLUTION: A multilayer ceramic electronic component comprises a ceramic element body, and first and second external electrodes. The ceramic element body has: an electrode lamination part in which internal electrodes are laminated; and first and second cover parts opposed to each other in a first axial direction while sandwiching the electrode lamination part therebetween. Each of the first and second external electrodes has: a coating part that covers the ceramic element body from a second axial direction; and an extending part that extends in the second axial direction on the cover parts. The ceramic element body includes ceramic crystal grains and segregation particles located between crystal grains. At a cross section of an end part region of the cover parts located between the extending part and the electrode lamination part, the number of small particles that have a particle diameter of 0.5% to 10% of an average particle diameter of crystal grains, among the segregation particles, is 40% to 95% of the number of the crystal grains.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic electronic component provided with external electrodes.

Background Art

[0002] In a multilayer ceramic capacitor, the insulation resistance may decrease due to the diffusion of hydrogen into the ceramic element body, resulting in a decrease in reliability. The diffusion of hydrogen into the ceramic element body is likely to occur, for example, when hydrogen generated in a wet plating process for forming external electrodes remains occluded in the external electrodes.

[0003] On the other hand, Patent Document 1 discloses a technique for making it difficult for hydrogen in the external electrode to diffuse into the ceramic element body. In this technique, by adding a metal having an action of suppressing the absorption of hydrogen to the internal electrode, it is possible to suppress the diffusion of hydrogen in the external electrode into the ceramic element body along the path of the internal electrode.

[0004] [[ID=1⑨]] Further, Patent Document 2 discloses a technique for suppressing the intrusion of hydrogen from the external electrode into the ceramic element body. In this technique, Mo having an action of preventing the permeation of hydrogen is added to the underlayer of the external electrode. Thereby, it is possible to prevent hydrogen generated when forming a plating layer on the underlayer from intruding into the ceramic element body.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, multilayer ceramic electronic components have been incorporated into automotive electronic devices and other applications. Therefore, there is a demand for highly reliable multilayer ceramic electronic components that do not experience a decrease in insulation resistance even under harsh environments such as high temperatures.

[0007] In view of the above circumstances, the object of the present invention is to provide a multilayer ceramic electronic component with high reliability. [Means for solving the problem]

[0008] To achieve the above objective, a multilayer ceramic electronic component according to one embodiment of the present invention comprises a ceramic body and first and second external electrodes. The ceramic body comprises an electrode stacking portion including ceramic layers stacked in the first axial direction and internal electrodes disposed between the ceramic layers, and first and second cover portions facing each other in the first axial direction with the electrode stacking portion in between. The first and second external electrodes each have a covering portion that covers the ceramic body from a second axial direction perpendicular to the first axis, and an extending portion that extends along the second axial direction on at least one of the first cover portion or the second cover portion. The aforementioned ceramic material is It includes ceramic crystal grains and segregation particles located between the crystal grains. At least one of the first or second cover portion is Including the end region located between the extended portion and the electrode stacked portion, In the cross-section of the end region, the number of small particles among the segregated particles having a particle size of 0.5% to 10% of the average particle size of the crystal grains is 40% to 95% of the total number of crystal grains.

[0009] In this configuration, in the cross-section of the end region of the cover located between the external electrode and the electrode stack, the number of small particles with a particle size of 0.5% to 10% of the average particle size of the crystal grains is between 40% and 95% of the total number of crystal grains. As a result, the propagation of hydrogen released from the external electrode to the end region is inhibited by a large number of small particles, suppressing the decrease in insulation resistance due to the effects of hydrogen. Furthermore, by segregating a large number of small particles with the above particle size, the excessive addition of additives can be suppressed compared to the case where a large number of segregating particles with a large particle size are segregated, thereby suppressing defects such as over-sintering of the ceramic body. Therefore, the reliability of the multilayer ceramic electronic component can be improved.

[0010] For example, the segregated particles may contain silicon. Furthermore, the segregated particles may contain at least one of rare earth elements or alkaline earth metal elements.

[0011] Furthermore, segregated particles may be present at the triple point.

[0012] For example, the average grain size of the crystal grains in the cross-section of the end region may be 50 nm or more and 500 nm or less, and furthermore, 170 nm or more and 250 nm or less.

[0013] Furthermore, the number of segregated particles per unit area in the cross-section of the ceramic layer may be less than the number of segregated particles per unit area in the cross-section of the end region. This makes it possible to suppress the decrease in the dielectric constant of the ceramic layer due to segregated particles.

[0014] Furthermore, at least one of the first or second cover portion is The central region located between the first and second external electrodes in the second axial direction may be included. In this case, in the cross-section of the central region, the average grain size of the crystal grains in the surface portion in the first axial direction is larger than the average grain size of the crystal grains in the central portion in the first axial direction. Also, in this case, in the cross-section of the central region, the number of segregation particles per unit area in the first axial surface layer portion may be less than the number of segregation particles per unit area in the first axial central portion. Thereby, the risk of moisture intrusion from the surface layer portion of the central region not covered by the external electrode can be suppressed. Therefore, it is possible to suppress a decrease in the insulation resistance of the multilayer ceramic electronic component due to the influence of moisture, and the reliability of the multilayer ceramic electronic component can be further enhanced.

[0015] For example, the crystal grains may contain barium and titanium. Also, for example, the crystal grains may contain at least one of calcium or zirconium.

[0016] The multilayer ceramic electronic component according to another aspect of the present invention includes a ceramic body, a first external electrode, and a second external electrode. The ceramic body includes an electrode laminate portion including ceramic layers laminated in a first axial direction and internal electrodes disposed between the ceramic layers, and first and second side margin portions facing each other in a second axial direction orthogonal to the first axis with the electrode laminate portion interposed therebetween. The first and second external electrodes each have a covering portion that covers the ceramic body from a third axial direction orthogonal to the first axis and the second axis, and an extending portion that extends along the third axial direction on at least one of the first side margin portion or the second side margin portion. The ceramic body includes ceramic crystal grains and segregation particles located between the crystal grains. At least one of the first or second side margin portions includes an end region located between the extending portion and the electrode laminate portion, and in the cross-section of the end region, the number of small particles having a particle size of 0.5% or more and 10% or less of the average particle size of the crystal grains among the segregation particles is 40% or more and 95% or less of the number of crystal grains.

[0017] In this configuration, in the cross-section of the end region of the side margin portion located between the external electrode and the electrode laminate portion, the number of small particles having a particle size of 0.5% or more and 10% or less of the average grain size of the crystal grains among the segregation particles is 40% or more and 95% or less of the number of crystal grains. Also by this, the decrease in insulation resistance due to the influence of hydrogen is suppressed. In addition, excessive addition of additives can be suppressed, and problems such as over-sintering of the ceramic body can be suppressed. Therefore, the reliability of the multilayer ceramic electronic component can be enhanced.

Advantages of the Invention

[0018] As described above, according to the present invention, a multilayer ceramic electronic component having high reliability can be provided.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective view of a multilayer ceramic capacitor according to the first embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along the line A-A' of FIG. 1 of the above multilayer ceramic capacitor. [Figure 3] It is a cross-sectional view taken along the line B-B' of FIG. 1 of the above multilayer ceramic capacitor. [Figure 4] It is a diagram schematically showing the microstructure of the region R1 in FIG. 2. [Figure 5] It is a diagram schematically showing the microstructure of the ceramic body of a multilayer ceramic capacitor according to a comparative example of the present embodiment. [Figure 6] It is a further enlarged view of a part of FIG. 4. [Figure 7] It is a flowchart showing the manufacturing method of the above multilayer ceramic capacitor. [Figure 8] It is a plan view showing the manufacturing process of the above multilayer ceramic capacitor. [Figure 9] It is a perspective view showing the manufacturing process of the above multilayer ceramic capacitor.

Modes for Carrying Out the Invention

[0020] Embodiments of the present invention will be described below with reference to the drawings. The drawings show mutually orthogonal X, Y, and Z axes as appropriate. The X, Y, and Z axes define a fixed coordinate system fixed to the multilayer ceramic capacitor 10.

[0021] [Overall configuration of a multilayer ceramic capacitor] Figures 1-3 show a multilayer ceramic capacitor 10 according to one embodiment of the present invention. Figure 1 is a perspective view of the multilayer ceramic capacitor 10. Figure 2 is a cross-sectional view of the multilayer ceramic capacitor 10 along the line A-A' in Figure 1. Figure 3 is a cross-sectional view of the multilayer ceramic capacitor 10 along the line B-B' in Figure 1.

[0022] The multilayer ceramic capacitor 10 comprises a ceramic body 11, a first external electrode 14a, and a second external electrode 14b. Each external electrode 14a and 14b is also referred to as the external electrode 14.

[0023] The ceramic body 11 is constructed as a rectangular parallelepiped having a first end face E1 and a second end face E2 perpendicular to the X-axis, a first side face S1 and a second side face S2 perpendicular to the Y-axis, and a first main face M1 and a second main face M2 perpendicular to the Z-axis. Note that the term "rectangular parallelepiped" means that it is substantially rectangular in shape, and for example, the edges connecting each face of the ceramic body 11 may be rounded.

[0024] The main surfaces M1, M2, end surfaces E1, E2, and side surfaces S1, S2 of the ceramic body 11 are all configured as flat surfaces. In this embodiment, a flat surface does not have to be strictly planar as long as it is perceived as flat when viewed as a whole, and includes, for example, surfaces having minute irregularities on the surface or gently curved shapes within a predetermined range.

[0025] The multilayer ceramic capacitor 10 of this embodiment has the following dimensions, for example: The dimensions of the multilayer ceramic capacitor 10 in the X-axis direction are, for example, 0.2 mm to 3.5 mm. The dimensions of the multilayer ceramic capacitor 10 in the Y-axis direction are, for example, 0.1 mm to 2.8 mm. The dimensions of the multilayer ceramic capacitor 10 in the Z-axis direction are, for example, 0.1 mm to 2.8 mm. Note that the "dimensions" of the multilayer ceramic capacitor 10 in a certain direction refer to the maximum dimension in that direction. A multilayer ceramic capacitor 10 in which the dimensions in the Z-axis direction are larger than the dimensions in the Y-axis direction is a so-called high-back multilayer ceramic capacitor. High-back multilayer ceramic capacitors can effectively utilize the space in the height direction (Z-axis direction), so they can be mounted on a mounting board in a space-saving manner and can obtain a large capacitance.

[0026] Furthermore, in the following explanation, "inward in the X-axis direction" refers to the side approaching a virtual YZ plane that bisects the multilayer ceramic capacitor 10 in the X-axis direction, and "outward in the X-axis direction" refers to the side moving away from the above virtual YZ plane. "Inward in the Z-axis direction" refers to the side approaching a virtual XY plane that bisects the multilayer ceramic capacitor 10 in the Z-axis direction, and "outward in the Z-axis direction" refers to the side moving away from the above virtual XY plane.

[0027] The external electrodes 14a and 14b cover both ends of the ceramic body 11 in the X-axis direction. For example, the first external electrode 14a shown in Figure 1 extends from the first end face E1 of the ceramic body 11 to both main faces M1 and M2 and both side faces S1 and S2. The second external electrode 14b shown in Figure 1 extends from the second end face E2 of the ceramic body 11 to both main faces M1 and M2 and both side faces S1 and S2.

[0028] The ceramic body 11 has an electrode stacking portion 16, a first cover portion 17a, and a second cover portion 17b. The cover portions 17a and 17b face each other in the Z-axis direction with the electrode stacking portion 16 in between, and constitute the main surfaces M1 and M2 of the ceramic body 11. Each cover portion 17a and 17b is also referred to as cover portion 17.

[0029] The thickness of each cover portion 17 in the Z-axis direction can be, for example, 5 μm to 300 μm, from the viewpoint of achieving miniaturization while ensuring insulation. The thickness of each cover portion 17 in the Z-axis direction is the maximum dimension of each cover portion 17 in the Z-axis direction.

[0030] The ceramic body 11 may further have a first side margin portion 15a and a second side margin portion 15b that face each other in the Y-axis direction with the electrode stack portion 16 in between. Each side margin portion 15a, 15b is also referred to as the side margin portion 15. This ensures insulation of the Y-axis end of the electrode stack portion 16.

[0031] The electrode stacked portion 16 includes a ceramic layer 18 stacked in the Z-axis direction and internal electrodes 12 and 13 positioned between the ceramic layers 18. The first internal electrode 12 and the second internal electrode 13 are alternately arranged in the Z-axis direction via the ceramic layer 18. In this embodiment, both the ceramic layer 18 and the internal electrodes 12 and 13 are configured as sheets extending along the XY plane.

[0032] The first internal electrode 12 is led out to the first end face E1, which is covered by the first external electrode 14a. On the other hand, the second internal electrode 13 is led out to the second end face E2, which is covered by the second external electrode 14b. As a result, the first internal electrode 12 is connected only to the first external electrode 14a, and the second internal electrode 13 is connected only to the second external electrode 14b.

[0033] With this configuration, when a voltage is applied between the external electrodes 14a and 14b of the multilayer ceramic capacitor 10, a voltage is applied to multiple ceramic layers 18 between the internal electrodes 12 and 13. As a result, the multilayer ceramic capacitor 10 stores a charge corresponding to the voltage between the external electrodes 14a and 14b.

[0034] The internal electrodes 12 and 13 mainly consist of a metallic material. Typical examples of this metallic material include nickel (Ni), but other examples include copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), and alloys thereof.

[0035] The thickness of each internal electrode 12, 13 in the Z-axis direction can be, for example, 0.5 μm or more and 2.0 μm or less. The thickness of the internal electrodes 12, 13 is the average value of the thickness measured at multiple locations on the internal electrodes 12, 13. As an example, six layers are selected from the internal electrodes 12, 13 in the field of view observed by a scanning electron microscope (SEM) or transmission electron microscope (TEM), and the thickness is measured at five equally spaced locations within each layer. The average value of the obtained 30 thicknesses is then taken as the thickness of the internal electrodes 12, 13.

[0036] The thickness of each ceramic layer 18 in the Z-axis direction can be, for example, 0.4 μm to 15 μm. This makes it possible to make the thickness of each ceramic layer 18 in the Z-axis direction greater than or equal to the grain size of the dielectric ceramics described later, and to increase the capacitance. The thickness of the ceramic layer 18 is the average value of the thickness measured at multiple locations on the ceramic layer 18. As an example, six layers are selected from the ceramic layers 18 in the field of view observed by SEM or TEM, and the thickness is measured at five equally spaced locations on each layer. The average value of the obtained 30 thicknesses is then taken as the thickness of the ceramic layer 18.

[0037] The ceramic body 11 mainly contains dielectric ceramics. The dielectric ceramics contained in the ceramic body 11 have a perovskite structure represented by the general formula ABO3, for example. Examples of dielectric ceramics having a perovskite structure include materials containing barium (Ba) and titanium (Ti), such as barium titanate (BaTiO3). In addition, the dielectric ceramics having a perovskite structure may also be a material containing at least one of calcium (Ca) or zirconium (Zr).

[0038] Specifically, the dielectric ceramic may be composed of barium titanate, strontium titanate (SrTiO3), calcium titanate (CaTiO3), magnesium titanate (MgTiO3), calcium zirconate (CaZrO3), calcium zirconate titanate (Ca(Ti,Zr,Ti)O3), barium calcium zirconate titanate ((Ba,Ca)(Ti,Zr)O3), barium zirconate (BaZrO3), titanium oxide (TiO2), and others. The ceramic element 11 may contain dielectric ceramics of multiple compositions.

[0039] Furthermore, the ceramic element 11 may contain other components in addition to dielectric ceramics. For example, the ceramic body 11 may contain silicon (Si) as a minor component, from the viewpoint of improving sinterability and suppressing structural defects. Furthermore, the ceramic body 11 may contain at least one of rare earth elements or alkaline earth metal elements. Examples of rare earth elements include yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), samarium (Sm), neodymium (Nd), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), and ytterbium (Yb). Examples of alkaline earth metal elements include magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). Furthermore, the ceramic body 11 may contain vanadium (V), manganese (Mn), lithium (Li), sodium (Na), potassium (K), and other elements as minor components.

[0040] The compositions of the ceramic layer 18, the cover portion 17, and the side margin portion 15 may be the same or different. From the viewpoint of mitigating stress caused by differences in physical properties between the electrode stacked portion 16 and its surroundings, it is preferable that the cover portion 17 and / or the side margin portion 15 contain dielectric ceramics of the same composition system as the ceramic layer 18.

[0041] [External electrode configuration] In this embodiment, the first and second external electrodes 14a and 14b each have a covering portion 141 that covers the ceramic body 11 from the X-axis direction, and a first extending portion 142 that extends along the X-axis direction on the cover portion 17. In this embodiment, the first and second external electrodes 14a and 14b each have a second extending portion 143 that extends along the X-axis direction on the side margin portion 15. In this embodiment, the first extending portion 142 is also referred to as the extending portion 142.

[0042] Furthermore, in this embodiment, the external electrode 14 has multiple layers. Specifically, the external electrode 14 has a base layer 144 disposed on the ceramic body 11 and a plating layer 145 disposed on the base layer 144.

[0043] The base layer 144 may be, for example, a sintered metal film formed by baking a conductive metal paste, or it may have a laminated structure such as a sintered metal film and a sputtered film. For example, the base layer 144 may contain at least one of nickel (Ni), copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), or an alloy thereof.

[0044] The plating layer 145 comprises one or more plating films. Each plating film of the plating layer 145 may mainly consist of, for example, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), or an alloy thereof.

[0045] It is known that hydrogen generated during wet plating processes for forming the plating layer 145 is absorbed by the external electrode 14. This hydrogen can exist in various states, such as hydrogen atoms, hydrogen ions, and hydrogen isotopes.

[0046] When a voltage is applied between the external electrodes 14a and 14b, the hydrogen absorbed by the external electrodes 14a and 14b is affected by the electric field and diffuses into the ceramic element 11. This hydrogen can degrade the ceramic element 11, potentially leading to a decrease in the insulation resistance of the multilayer ceramic capacitor 10.

[0047] In this embodiment, the cover portion 17 includes a first end region (end region) 171 located between the extended portion 142 of the external electrode 14 and the electrode stacked portion 16. This end region 171 is particularly likely to become a hydrogen migration path from the extended portion 142 to the electrode stacked portion 16. Therefore, the inventors have found that by segregating a large number of small particles of a predetermined size in the end region 171 of the cover portion 17, the decrease in insulation resistance in the multilayer ceramic capacitor 10 can be suppressed. The details of the microstructure of the ceramic element 11 will be described below.

[0048] [Microstructure of ceramic material] Figure 4 is a schematic partial cross-sectional view showing the microstructure of the ceramic body 11, and is a diagram showing region R1 within the end region 171 shown in Figure 2.

[0049] The ceramic body 11, which includes the ceramic layer 18, the cover portion 17, and the side margin portion 15, is a polycrystalline material containing dielectric ceramic crystal grains 20. In Figure 4 and Figure 5 described later, the crystal grains 20 are represented as large, white particles densely arranged throughout.

[0050] The crystal grains 20 mainly consist of the dielectric ceramics described above and have a crystal structure such as a perovskite structure. For example, the crystal grains 20 may contain barium (Ba) and titanium (Ti) as elements constituting the dielectric ceramics, and may also contain barium titanate (BaTiO3). In addition, the crystal grains 20 may contain at least one of calcium (Ca) or zirconium (Zr) as elements constituting the dielectric ceramics. It is preferable that the crystal grains 20 of the ceramic layer 18, the cover portion 17, and the side margin portion 15 contain the same dielectric ceramics, but they may contain different dielectric ceramics.

[0051] In the ceramic body 11, during the firing process, the raw ceramic particles aggregate, forming a polycrystalline body in which crystal grains 20 are densely arranged. In the ceramic body 11, grain boundaries 22 are formed between the crystal grains 20, and furthermore, triple points 23 are formed in the gaps surrounded by three or more crystal grains 20. In this embodiment, the "triple point 23" is not limited to the gaps between three crystal grains 20, but also includes gaps between four or more crystal grains 20.

[0052] Furthermore, the ceramic body 11 contains segregated particles 21 located between the crystal grains 20. The segregated particles 21 are formed during the firing process of the ceramic body 11 when elements such as minor components that were not included in the crystal grains 20 segregate. In Figures 4 and 5, the segregated particles 21 are represented as black granular structures.

[0053] The segregation particles 21 have a composition corresponding to the minor components added to the ceramic body 11, and for example, they contain Si. Furthermore, the segregation particles 21 may contain at least one of the rare earth elements or alkaline earth metal elements listed above as minor components. The segregation particles 21 are, for example, oxides, but are not limited thereto. The segregation particles 21 may have a crystalline structure, or they may be amorphous.

[0054] At the triple point 23, gaps are easily formed between the crystal grains 20, making it easy for segregation to occur. For this reason, segregation particles 21 are often located at the triple point 23, in which case they are less likely to diffuse and are stable under thermal and temporal history, but they can also be located at the grain boundaries 22.

[0055] The formation of segregated particles 21 between crystal grains 20 can be confirmed, for example, by performing elemental analysis on a cross-section of the multilayer ceramic capacitor 10, such as scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), transmission electron microscopy-energy dispersive X-ray analysis (TEM-EDX), or wavelength dispersive X-ray analysis (WDX).

[0056] When a voltage is applied between the external electrodes 14a and 14b, hydrogen is thought to move through crystal defects within the crystal grains 20 in the ceramic body 11. If segregation particles 21 are placed between adjacent crystal grains 20, hydrogen has difficulty entering the segregation particles 21 and therefore moves to avoid them. By placing segregation particles 21 between the crystal grains 20 that serve as the hydrogen's movement path, the linear movement of hydrogen can be inhibited, and the time it takes for hydrogen to reach the electrode stacking section 16 can be delayed.

[0057] On the other hand, as shown in the microstructure of Figure 5 relating to a comparative example of this embodiment, if segregated material aggregates to form large segregated particles 21, the segregated particles 21 are not dispersed, and it is difficult to obtain the effect of inhibiting hydrogen progression. Furthermore, in order to form a large number of such large segregated particles 21, it becomes necessary to add an excessive amount of auxiliary components, which can lead to problems such as oversintering of the ceramic body 11.

[0058] Therefore, in this embodiment, by arranging a large number of segregated particles 21 with a low degree of aggregation and small particle size between the crystal grains 20, the progression of hydrogen can be effectively inhibited.

[0059] As segregated particles 21 with small particle size, we define small particles 21a having a particle size of 0.5% to 10% of the average particle size of the crystal grains 20. Specifically, in the cross-section of the end region 171 of the cover portion 17 in this embodiment, when the number of crystal grains 20 is set to 100%, the number of small particles 21a is 40% to 95% of the number of crystal grains 20.

[0060] In this embodiment, the cross-sections of each part of the ceramic body 11 are preferably, for example, cross-sections parallel to the Z-axis direction, and more preferably, cross-sections parallel to the X-axis direction and the Z-axis direction (cross-sections parallel to the XZ plane) as shown in Figure 2.

[0061] Segregated particles 21 smaller than 0.5% of the average particle size of the crystal grains 20 are difficult to count due to their small size, and also do not effectively suppress hydrogen diffusion. On the other hand, in order to form a large number of segregated particles 21 larger than 10% of the average particle size of the crystal grains 20, it becomes necessary to add an excessive amount of the minor component, as described above. Therefore, by forming a large number of small particles 21a in the edge region 171 that are between 0.5% and 10% of the average particle size of the crystal grains 20, it is possible to suppress the adverse effects of hydrogen while suppressing defects in the ceramic body 11 caused by the excessive addition of the minor component.

[0062] In the cross-section of the end region 171, by setting the number ratio of small particles 21a to crystal grains 20 to 40% or more, the time until deterioration of insulation resistance begins in high-temperature load tests can be sufficiently extended, as shown in the examples described later. This makes it possible to obtain a highly reliable multilayer ceramic capacitor 10 that is less prone to deterioration even under harsh environments. Furthermore, by setting the number ratio of small particles 21a to crystal grains 20 to, for example, 70% or more, the deterioration of insulation resistance can be suppressed more effectively.

[0063] Since it is practically difficult to make the number ratio of small particles 21a to crystal grains 20 greater than 95%, in this embodiment, the number ratio of small particles 21a to crystal grains 20 in the cross-section of the end region 171 is set to 95% or less.

[0064] This section describes how to calculate the ratio of the number of small particles 21a (small particle number ratio) when the number of crystal grains 20 is set to 100% in this embodiment.

[0065] First, the cross-section of the cover portion 17 is exposed by polishing the ceramic body 11. This cross-section is, for example, parallel to the XZ plane and passes through the center of the ceramic body 11 in the Y-axis direction. Next, the cross-section is magnified 10,000 to 100,000 times using a SEM or TEM to observe the end region 171 of the cover portion 17. The position of the object to be observed may be, for example, the center of the end region 171 in the Z-axis direction, as shown in region R1 in Figure 2. Alternatively, the position of the object to be observed may be between the end portion 14e (see Figure 2) of the extension portion 142 in the X-axis direction and the electrode stacked portion 16. However, the position of the object to be observed is not limited to these.

[0066] A region containing 50 or more crystal grains 20 is designated as the observation area for calculating the small particle count ratio, and is imaged. The observation area is preferably a single field of view, but may consist of multiple consecutive fields of view. Crystal grains 20 that are only partially present within the observation area are not counted.

[0067] Next, the average grain size of the crystal grains 20 is calculated using the image of the observed region. First, as shown in Figure 6, the longest dimension L11 of one crystal grain 20 is measured, and the longest width dimension L12 is measured in the direction perpendicular to the line segment defining the longest dimension L11. The average value of this longest dimension L11 and width dimension L12 is taken as the grain size of that particle. The average grain size of 50 crystal grains 20 within the observed region is calculated, and this value is taken as the average grain size of the crystal grains 20.

[0068] Next, within the observation area described above, the particle size of each segregated particle 21 present between the crystal grains 20 is calculated using the same method as for the crystal grains 20. Specifically, as shown in the enlarged view enclosed by the dashed line in Figure 6, the longest dimension L21 of a single segregated particle 21 is measured, and the longest width dimension L22 is measured in the direction perpendicular to the line segment defining the longest dimension L21. The average of this longest dimension L21 and width dimension L22 is taken as the particle size of that segregated particle 21.

[0069] Next, the number of small particles 21a that make up 0.5% to 10% of the average particle size of the crystal grains 20 is counted from all segregated particles 21 within the observation area. However, small particles 21a that are only partially present within the observation area are not counted. Finally, the ratio of the number of small particles 21a to the number of crystal grains 20 within the observation area (number of small particles / number of crystal grains × 100) is calculated.

[0070] The average grain size of the crystal grains 20 in the cross-section of the end region 171, calculated based on the method described above, is, for example, 50 nm to 500 nm, and preferably, for example, 170 nm to 250 nm. Segregated particles 21 tend to aggregate during the firing process as the crystal grains 20 grow. Therefore, by setting the average grain size of the crystal grains 20 in the cross-section of the end region 171 to, for example, 50 nm to 500 nm, aggregation of segregated particles 21 in the end region 171 can be suppressed, making it easier to adjust the number ratio of small particles 21a to 40% or more. In particular, by setting the average grain size of the crystal grains 20 in the cross-section of the end region 171 to 170 nm to 250 nm, as shown in the examples described later, the number ratio of small particles 21a can be sufficiently increased, and the decrease in insulation resistance can be suppressed more effectively.

[0071] On the other hand, if a large number of segregation particles 21 are formed in the ceramic layer 18, the dielectric constant of the ceramic layer 18 may decrease, potentially reducing the capacitance of the multilayer ceramic capacitor 10.

[0072] Therefore, in this embodiment, it is preferable that the number of segregation particles 21 per unit area in the cross-section of the ceramic layer 18 is less than the number of segregation particles 21 per unit area in the cross-section of the edge region 171. This makes it possible to improve reliability while maintaining the capacitance of the multilayer ceramic capacitor 10.

[0073] The number of segregated particles 21 in the ceramic layer 18 can also be counted in the same way as in the end region 171 described above. Specifically, a cross-section is exposed from the multilayer ceramic capacitor 10 using the method described in "Method for Calculating the Ratio of Small Particles". This cross-section may be the same cross-section used to calculate the ratio of small particles. Using an SEM or TEM, the cross-section is magnified 10,000 to 100,000 times, and an observation area containing 50 or more crystal grains 20 is imaged. The number of segregated particles 21 contained in each observation area of ​​the end region 171 and the ceramic layer 18 is counted. However, segregated particles 21 that are only partially present within the observation area are not counted. Next, the area of ​​each observation area is calculated, and the number of counted segregated particles 21 is divided by this area. This allows the number of segregated particles 21 per unit area in each of the end region 171 and the ceramic layer 18 to be calculated.

[0074] On the other hand, the cover portion 17 includes a central region 172 located between the external electrodes 14a and 14b in the X-axis direction. Since the central region 172 is not covered by the external electrodes 14, the risk of hydrogen diffusion from the external electrodes 14 is low, but the risk of moisture intrusion from outside the multilayer ceramic capacitor 10 is high. Therefore, in this embodiment, in addition to the configuration of the end region 171 described above, the central region 172 is configured as follows, which can suppress the decrease in insulation resistance due to moisture intrusion and further improve the reliability of the multilayer ceramic capacitor 10.

[0075] Specifically, in the cross-section of the central region 172, it is preferable that the average grain size of the crystal grains 20 in the Z-axis direction surface layer 172a is larger than the average grain size of the crystal grains 20 in the Z-axis direction central region 172b. Such a configuration can be achieved, for example, by forming the cover portion 17 with a plurality of ceramic sheets, and making the average grain size of the ceramic particles of the ceramic sheet at the position corresponding to the Z-axis direction surface layer 172a larger than the average grain size of the ceramic particles of the ceramic sheet at the position corresponding to the Z-axis direction central region 172b. Furthermore, the Z-axis oriented surface portion 172a of the central region 172 is defined as the region containing the main surfaces M1 and M2, obtained by dividing the central region 172 into three equal parts in the Z-axis direction. The Z-axis oriented central portion 172b of the central region 172 is defined as the central region, obtained by dividing the central region 172 into three equal parts in the Z-axis direction.

[0076] As a result, the crystal grains 20 on the Z-axis surface layer 172a of the central region 172 grow and become more densely arranged, reducing the risk of moisture entering the multilayer ceramic capacitor 10 from the outside.

[0077] Furthermore, as described above, since there is a relationship between the grain growth of the crystal grains 20 and the degree of aggregation of the segregated particles 21, it is preferable that the number of segregated particles 21 per unit area in the Z-axis surface layer 172a of the cross-section of the central region 172 is less than the number of segregated particles 21 per unit area in the Z-axis central region 172b.

[0078] The method for comparing the Z-axis surface portion 172a and the Z-axis central portion 172b of the central region 172 will be explained.

[0079] A cross-section is exposed from the multilayer ceramic capacitor 10 using the method described in "Method for Calculating the Ratio of Small Particles". This cross-section may be the same cross-section used to calculate the ratio of small particles. Subsequently, the cross-section is magnified 10,000 to 100,000 times using an SEM or TEM, and regions containing 50 or more crystal grains 20 in the Z-axis surface portion 172a and the Z-axis central portion 172b of the central region 172 are imaged as observation areas.

[0080] Then, the average grain size of the crystal grains 20 contained in the imaged observation area is calculated for both the Z-axis surface layer 172a and the Z-axis central part 172b of the central region 172. The method for calculating the average grain size of the crystal grains 20 is the method described in "Method for Calculating the Ratio of Small Particles". This makes it possible to compare the average grain sizes of the crystal grains 20 in the Z-axis surface layer 172a and the Z-axis central part 172b in the cross-section of the central region 172.

[0081] Next, the number of segregated particles 21 contained in each observation target area of ​​the Z-axis surface layer 172a and the Z-axis central part 172b of the central region 172 is counted. However, segregated particles 21 that are only partially present within the observation target area are not counted. Subsequently, the area of ​​each observation target area is calculated, and the number of counted segregated particles 21 is divided by this area. This allows the number of segregated particles 21 per unit area in each cross-section of the Z-axis surface layer 172a and the Z-axis central part 172b of the central region 172 to be calculated.

[0082] [Manufacturing method for multilayer ceramic capacitors] Figure 7 is a flowchart showing the manufacturing method of the multilayer ceramic capacitor 10. Figures 8 and 9 show the manufacturing process of the multilayer ceramic capacitor 10. The manufacturing method of the multilayer ceramic capacitor 10 will be described below in accordance with Figure 7, with appropriate reference to Figures 8 and 9.

[0083] (Step S01: Prepare the ceramic sheet) In step S01, a first ceramic sheet 101 and a second ceramic sheet 102 for forming the electrode stacked portion 16, and a cover ceramic sheet 103 for forming the cover portion 17 are prepared. The ceramic sheets 101, 102, and 103 are configured as large sheets having regions corresponding to multiple ceramic elements 11.

[0084] The ceramic sheets 101, 102, and 103 shown in Figures 8A, B, and C are constructed as unfired ceramic green sheets. First, the materials for the ceramic green sheets are mixed to obtain a slurry. This slurry contains dielectric ceramic powder, binder resin, organic solvent, and additives. The slurry, obtained by mixing these materials in a ball mill or the like, is formed into a sheet using a roll coater or doctor blade. The ceramic sheets 101, 102 and the cover ceramic sheet 103 may have the same composition or different compositions.

[0085] In this embodiment, the dielectric ceramics that form the main component of the ceramic sheets 101, 102, and 103 can be any of the materials listed above as dielectric ceramics. Furthermore, it is preferable that the additive contains silicon (Si) as listed above as a minor component. In addition, the additive may contain at least one of the rare earth elements or alkaline earth metal elements listed above as minor components.

[0086] In this embodiment, the Si content in the cover ceramic sheet 103 can be set to 0.1 to 2.5 atm%, assuming the elemental concentration at the B site of the dielectric ceramic is 100 atm%. This adjusts the sinterability of the ceramic body 11 in the firing process described later, allowing for the segregation of a large number of small Si particles 21a. Furthermore, the content of other additives can be appropriately adjusted in consideration of the sinterability of the ceramic body 11, etc.

[0087] The thickness of ceramic sheets 101 and 102 is adjusted according to the thickness of the ceramic layer 18 after firing. The thickness of ceramic sheet 103 is adjusted as appropriate according to the thickness of the cover portion 17 after firing.

[0088] As shown in Figure 8, an unfired first internal electrode pattern 112 corresponding to the first internal electrode 12 is formed on the first ceramic sheet 101, and an unfired second internal electrode pattern 113 corresponding to the second internal electrode 13 is formed on the second ceramic sheet 102. The internal electrode patterns 112 and 113 can be formed by printing a conductive paste onto the ceramic sheets 101 and 102. Note that no internal electrode pattern is formed on the cover ceramic sheet 103.

[0089] Each ceramic sheet 101, 102, and 103 shows the cut lines Lx and Ly used to separate the ceramic body 11 into individual pieces. Each internal electrode pattern 112 and 113 is configured in a rectangular shape, for example, extending across a single cut line Ly. However, the second internal electrode pattern 113 is formed offset from the first internal electrode pattern 112 by one chip in the X-axis or Y-axis direction.

[0090] (Step S02: Lamination) In step S02, as shown in Figure 9, ceramic sheets 101, 102, and 103 are stacked to create a laminated sheet 104.

[0091] In the laminated sheet 104 shown in Figure 9, ceramic sheets 101 and 102 forming the electrode laminated portion 16 are stacked alternately, and cover ceramic sheets 103 are stacked above and below them in the Z-axis direction. These ceramic sheets 101, 102, and 103 are integrated by being pressed together. Note that the number of ceramic sheets 101, 102, and 103 is not limited to the example shown in Figure 9.

[0092] (Step S03: Cutting) In step S03, the laminated sheet 104 is cut along the cut lines Lx and Ly to produce an unfired ceramic body 11.

[0093] (Step S04: Firing) In step S04, the unfired ceramic body 11 is sintered. This produces the ceramic body 11 shown in Figures 1-3. The firing can be carried out, for example, under a reducing atmosphere or a low oxygen partial pressure atmosphere.

[0094] In this embodiment, by adjusting the firing conditions, small particles 21a with a number ratio of 40% to 95% of the crystal grains 20 can be formed in the edge region 171. For example, by maintaining a lower firing temperature for a short time and then rapidly cooling it down, the number of small particles 21a can be increased. The specific firing temperature, heating rate, and cooling rate can be adjusted by the composition of the ceramic slurry used in the ceramic body 11. As an example, when using a barium zirconate calcium titanium-zirconate-based material as the dielectric ceramic, the firing temperature is set to approximately 1250-1300°C, and the oxygen partial pressure in the highest temperature range is set to 10 -11 ~10 -10The temperature should be set to approximately (atm), maintained at the firing temperature for 5 seconds to 1 minute, and then cooled. For example, the heating rate and cooling rate can be adjusted between 50 and 150°C / min.

[0095] (Step S05: External electrode formation) In step S05, external electrodes 14a and 14b are formed on the X-axis ends of the fired ceramic body 11 to create the multilayer ceramic capacitor 10 shown in Figures 1 to 3.

[0096] For example, conductive paste is applied to both ends of the ceramic body 11 in the X-axis direction and baked to form a base layer 144. The conductive paste can be applied by a dipping method, a printing method, or the like. One or more plating films can be formed on this base layer 144 to form a plating layer 145. Each plating film can be formed, for example, by an electrolytic plating method.

[0097] Through the above steps, the multilayer ceramic capacitor 10 shown in Figures 1 to 3 is manufactured. Note that the manufacturing method in this embodiment is not limited to the example described above. For example, the application of the conductive paste in step 05 may be performed before the firing process in step S04. This allows the underlayer 144 to be formed simultaneously with the firing of the ceramic body 11.

[0098] According to this embodiment, even if hydrogen generated by the formation of the plating layer 145 is absorbed by the external electrode 14, a large number of small particles 21a are segregated in the end region 171 of the cover portion 17, thereby suppressing the diffusion of hydrogen into the electrode stacked portion 16. Therefore, a decrease in the reliability of the multilayer ceramic capacitor 10 can be suppressed.

[0099] [Examples and Comparative Examples] Examples and comparative examples of the above embodiments will now be described. In Examples 1 to 8, samples of multilayer ceramic capacitors were prepared under conditions in which the ratio of small particles in the cross-section of the edge region of the cover portion was 40% to 95% of the number of crystal grains. In Comparative Examples 1 and 2, samples of multilayer ceramic capacitors were prepared under conditions in which the ratio of small particles was less than 40%. The ratio of small particles was adjusted by the composition of the cover portion, the firing temperature, and the duration of holding the firing temperature.

[0100] In Examples 1-8 and Comparative Examples 1 and 2, the size of the multilayer ceramic capacitor sample was set to 1.0 mm × 0.5 mm × 0.5 mm. The Z-axis dimension of each cover portion was set to 80 μm. Furthermore, in Examples 1-8 and Comparative Examples 1 and 2, the configuration of the multilayer ceramic capacitor sample was substantially the same except for the small particle number ratio mentioned above.

[0101] (Example 1) In Example 1, first, first and second ceramic sheets printed with conductive paste, and a cover ceramic sheet without conductive paste were prepared. The cover ceramic sheet contained a dielectric ceramic as the main component and additives. The dielectric ceramic as the main component was barium calcium zirconate titanate ((Ba,Ca)(Ti,Zr)O3, BCTZ) containing Ba, Ca, Ti, and Zr. In this dielectric ceramic, the ratio of the sum of the number of Ba and Ca atoms to the sum of the number of Ti and Zr atoms ((Ba+Ca) / (Ti+Zr)) was set to 0.997. The additives included Ca, Zr, Ho, Mg, Mn, V, and Si. As shown in Table 1, when (Ti+Zr) was set to 100 atm%, the Mg content was 1.5 atm% and the Si content was 1.0 atm%.

[0102] These ceramic sheets were laminated and compressed as shown in Figure 9 to produce a laminated sheet, and this laminated sheet was cut to produce an unfired ceramic body. Next, the unfired ceramic body was fired. In the firing process, as shown in Table 1, the firing temperature was set to 1260°C and the firing temperature was maintained for 0.1 minutes. Then, by forming a base layer and a plating layer, an external electrode as shown in Figures 1 to 3 was formed. This produced the sample of Example 1.

[0103] (Example 2) As shown in Table 1, the sample for Example 2 was prepared in the same manner as in Example 1, except that the Mg content was set to 1.0 atm% when (Ti + Zr) was set to 100 atm%.

[0104] (Example 3) As shown in Table 1, the sample for Example 3 was prepared in the same manner as in Example 1, except that the Si content of the ceramic sheet for the cover was set to 1.5 atm% when (Ti + Zr) was set to 100 atm%, and the firing temperature was set to 1250°C.

[0105] (Example 4) As shown in Table 1, the sample for Example 4 was prepared in the same manner as in Example 1, except that Mg was not added as an additive to the ceramic sheet for the cover and the firing temperature was set to 1250°C.

[0106] (Comparative Example 1) As shown in Table 1, a sample for Comparative Example 1 was prepared in the same manner as in Example 1, except that the firing temperature maintenance time was set to 12 minutes.

[0107] (Example 5) Sample for Example 5 was prepared in the same manner as in Example 1, except that the composition of the ceramic sheet for the cover and the firing temperature were changed.

[0108] In Example 5, the ceramic sheet for the cover, corresponding to the cover portion, contained barium titanate (BaTiO3, BT) containing Ba and Ti as the main dielectric ceramic component. In this dielectric ceramic, the ratio of the number of Ba atoms to the number of Ti atoms (Ba / Ti) was 0.998. The additives in the ceramic sheet for the cover contained Ho, Mg, Mn, V, and Si. As shown in Table 1, when Ti was set to 100 atm%, the Mg content was 1.5 atm% and the Si content was 1.0 atm%. In Example 5, the firing temperature was 1275°C.

[0109] (Example 6) As shown in Table 1, the sample for Example 6 was prepared in the same manner as in Example 5, except that the Mg content was set to 1.0 atm% when Ti was set to 100 atm% for the ceramic sheet additives used for the cover.

[0110] (Example 7) As shown in Table 1, the sample for Example 7 was prepared in the same manner as in Example 5, except that the additives for the ceramic sheet for the cover were set to 1.5 atm% of Si when Ti was set to 100 atm%, and the firing temperature was set to 1260°C.

[0111] (Example 8) As shown in Table 1, the sample for Example 8 was prepared in the same manner as in Example 5, except that Mg was not added as an additive to the ceramic sheet for the cover and the firing temperature was set to 1260°C.

[0112] (Comparative Example 2) As shown in Table 1, a sample for Comparative Example 1 was prepared in the same manner as in Example 5, except that the firing temperature maintenance time was set to 12 minutes.

[0113] [Table 1]

[0114] (Average grain size of crystal grains) Each sample from the examples and comparative examples was polished to expose a cross-section parallel to the XZ plane and passing through the center of the multilayer ceramic capacitor in the Y-axis direction. Subsequently, the cross-section was magnified 30,000 to 50,000 times using a scanning electron microscope (SEM), and an observation area containing 50 or more crystal grains was imaged. The observation area was positioned at the location corresponding to region R1. That is, the location of this observation area was between the X-axis end of the external electrode and the electrode stacking portion in the cover, and in the center in the Z-axis direction. Then, the average grain size of the 50 crystal grains contained in this observation area was calculated according to the "Method for Calculating the Ratio of Small Particles" described above. The results are shown in Table 1.

[0115] As shown in Table 1, in Examples 1-8 and Comparative Examples 1-2, the average grain size of the crystal grains in the cross-section of the edge region was between 50 nm and 500 nm. Of Examples 1-8, in Examples 1, 4, 6, and 8, the average grain size of the crystal grains was between 170 nm and 250 nm.

[0116] (Calculation of the ratio of small particles) Next, using the images of the observed regions of each sample, the ratio of the number of small particles to the number of crystal grains (small particle ratio) was calculated according to the "Method for Calculating the Small Particle Ratio" described above.

[0117] First, the number of crystal grains within the observed region was calculated. Next, the particle size of each segregated particle located within the same observed region was calculated based on the particle size calculation method described above. Of the segregated particles for which the particle size was calculated, the number of small particles that accounted for 0.5% to 10% of the average particle size of the crystal grains was counted. Then, the ratio of the number of small particles (number of small particles / number of crystal grains × 100) to the total number of crystal grains within the observed region (set as 100%) was calculated as the "small particle count ratio". The results are shown in Table 1.

[0118] As shown in Table 1, in Examples 1 to 8, the small particle count ratio was between 40% and 95%. In contrast, in Comparative Examples 1 and 2, the small particle count ratio was 0%.

[0119] (High-temperature load test) Next, for Examples 1-8 and Comparative Examples 1 and 2, a voltage twice the rated voltage was applied at 125°C, and the time at which the leakage current value increased by 20% or more from the start of measurement (insulation resistance (IR) degradation onset time) was measured. The results are shown in Table 1.

[0120] As shown in Table 1, in Comparative Examples 1 and 2, where the small particle count ratio was 0%, the IR degradation onset time was 1000 hours or less in both cases. In contrast, in Examples 1 to 8, where the small particle count ratio was 40% to 95%, the IR degradation onset time was 2000 hours or more in all cases. This indicates that by setting the small particle count ratio in the edge region to 40% to 95%, the onset of IR degradation can be delayed even under harsh conditions.

[0121] Furthermore, in Examples 1, 4, 6, and 8, where the average grain size of the crystal grains was between 170 nm and 250 nm, the IR degradation onset time was 3000 hours or more. This indicates that the onset of IR degradation can be further delayed by setting the average grain size of the crystal grains in the edge regions to between 170 nm and 250 nm.

[0122] [Other embodiments] Although the main embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0123] In the first embodiment, a configuration was mainly described to suppress the diffusion of hydrogen released from the external electrode 14 to the first end region 171 of the cover portion 17. On the other hand, as shown in Figure 3, the side margin portion 15 also includes a second end region 151 located between the second extension portion 143 of the external electrode 14 and the electrode stacking portion 16, and is likely to become a hydrogen migration path. Therefore, by adjusting the ratio of small particles in the cross-section of the second end region 151 of the side margin portion 15, the diffusion of hydrogen released from the external electrode 14 to the second end region 151 of the side margin portion 15 can be suppressed.

[0124] Specifically, in the cross-section of the second end region 151 of the side margin portion 15, it is preferable that the number of small particles 21a among the segregated particles 21 having a particle size of 0.5% to 10% of the average particle size of the crystal grains 20 is 40% to 95% of the total number of crystal grains 20. This suppresses the diffusion of hydrogen in the second end region 151 and prevents a decrease in insulation resistance.

[0125] In this example, the multilayer ceramic capacitor 10 may be manufactured by a method in which the side margin portion 15 is added later. That is, after the laminate of ceramic sheets corresponding to the electrode laminate portion 16 and the cover portion 17 is separated into individual pieces, unfired side margin portions 15 are formed on both sides of the laminate in the Y-axis direction. By applying such a manufacturing method, it becomes easy to adjust the composition of the side margin portion 15.

[0126] Furthermore, by setting the number ratio of small particles to 40% or more and 95% or less in the cross-sections of both the first end region 171 of the cover portion 17 and the second end region 151 of the side margin portion 15, the decrease in insulation resistance can be further suppressed.

[0127] Furthermore, the configuration of the external electrode 14 is not limited to the example described above. For example, the first extension portion 142 may be formed on only one of the first main surface M1 or the second main surface M2. Also, the external electrode 14 does not have to be formed on the side surfaces S1 and S2.

[0128] Furthermore, although a multilayer ceramic capacitor 10 was described as an example of a multilayer ceramic electronic component in the above embodiment, the present invention is applicable to all multilayer ceramic electronic components having a pair of external electrodes. Examples of such multilayer ceramic electronic components include chip varistors, chip thermistors, and multilayer inductors. [Explanation of symbols]

[0129] 10 Multilayer ceramic capacitors 11 Ceramic Body 12,13 Internal electrode 14, 14a, 14b External electrodes 15, 15a, 15b Side margin parts 16 Electrode laminated part 17, 17a, 17b Cover parts 171 End region 172 Central region 20 Crystal grains 21 Segregation particles 21a Small particles E1, E2 End faces S1, S2 Side faces M1, M2 Main faces

Claims

1. A ceramic body having an electrode stacking portion including ceramic layers stacked in the first axial direction and internal electrodes disposed between the ceramic layers, and first and second cover portions facing each other in the first axial direction with the electrode stacking portion in between, First and second external electrodes each have a covering portion that covers the ceramic body from a second axial direction perpendicular to the first axis, and an extending portion that extends along the second axial direction on at least one of the first cover portion or the second cover portion, It is equipped with, The aforementioned ceramic material is It comprises ceramic crystal grains and segregation particles located between the crystal grains, At least one of the first or second cover portion is Including the end region located between the extended portion and the electrode stacked portion, In the cross-section of the end region, the number of small particles among the segregated particles having a particle size of 0.5% to 10% of the average particle size of the crystal grains is 40% to 95% of the total number of crystal grains. Multilayer ceramic electronic components.

2. A multilayer ceramic electronic component according to claim 1, The segregated particles contain silicon. Multilayer ceramic electronic components.

3. A multilayer ceramic electronic component according to claim 2, The segregated particles further include at least one of a rare earth element or an alkaline earth metal element. Multilayer ceramic electronic components.

4. A multilayer ceramic electronic component according to any one of claims 1 to 3, The segregated particles are located at the triple point. Multilayer ceramic electronic components.

5. A multilayer ceramic electronic component according to any one of claims 1 to 4, The average grain size of the crystal grains in the cross-section of the end region is 50 nm or more and 500 nm or less. Multilayer ceramic electronic components.

6. A multilayer ceramic electronic component according to claim 5, The average grain size of the crystal grains in the cross-section of the end region is 170 nm or more and 250 nm or less. Multilayer ceramic electronic components.

7. A multilayer ceramic electronic component according to any one of claims 1 to 6, The number of segregated particles per unit area in the cross-section of the ceramic layer is less than the number of segregated particles per unit area in the cross-section of the edge region. Multilayer ceramic electronic components.

8. A multilayer ceramic electronic component according to any one of claims 1 to 7, At least one of the first or second cover portion is The central region located between the first and second external electrodes in the second axial direction includes, In the cross-section of the central region, the average grain size of the crystal grains in the surface layer in the first axial direction is greater than the average grain size of the crystal grains in the central part in the first axial direction. Multilayer ceramic electronic components.

9. A multilayer ceramic electronic component according to any one of claims 1 to 8, At least one of the first or second cover portion is The central region located between the first and second external electrodes in the second axial direction includes, In the cross-section of the central region, the number of segregated particles per unit area in the first axial surface layer is less than the number of segregated particles per unit area in the central part of the first axial region. Multilayer ceramic electronic components.

10. A multilayer ceramic electronic component according to any one of claims 1 to 9, The aforementioned crystal grains contain barium and titanium. Multilayer ceramic electronic components.

11. A multilayer ceramic electronic component according to any one of claims 1 to 10, The aforementioned crystal grains contain at least one of calcium or zirconium. Multilayer ceramic electronic components.

12. A ceramic body having an electrode stacking portion including ceramic layers stacked in a first axial direction and internal electrodes disposed between the ceramic layers, and first and second side margin portions facing each other in a second axial direction perpendicular to the first axis, with the electrode stacking portion in between, The first and second external electrodes each have a covering portion that covers the ceramic body from a third axial direction perpendicular to the first and second axes, and an extending portion that extends along the third axial direction on at least one of the first side margin portion or the second side margin portion, It is equipped with, The aforementioned ceramic material is It comprises ceramic crystal grains and segregation particles located between the crystal grains, At least one of the first or second side margin portion is Including the end region located between the extended portion and the electrode stacked portion, In the cross-section of the end region, the number of small particles among the segregated particles having a particle size of 0.5% to 10% of the average particle size of the crystal grains is 40% to 95% of the total number of crystal grains. Multilayer ceramic electronic components.

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