Multilayer ceramic capacitor

Abstract

The present disclosure relates to a multilayer ceramic capacitor (100). The multilayer ceramic capacitor (100) according to the present disclosure comprises a laminate (110) having: an inner layer part (150) in which internal ceramic layers (130) and internal electrode layers (140) are alternately laminated; external ceramic layers (160) disposed on both sides of the inner layer part (150) in the lamination direction; and side surface ceramic parts (170) disposed on both sides of the inner layer part (150) and the external ceramic layers (160) in the width direction orthogonal to the lamination direction. In the internal ceramic layers (130), the external ceramic layers (160), and the side surface ceramic parts (170), the concentration of magnesium per 100 mol parts of the total amount of titanium and zirconium of a perovskite compound is 0.05 mol parts or less. The internal electrode layers (140) contain nickel as a main component, and the bonding ratio between the side surface ceramic parts (170) and the internal electrode layers (140) is 80% or more.

Description

Multilayer ceramic capacitor

[0001] This disclosure relates to multilayer ceramic capacitors.

[0002] Japanese Patent Publication No. 2022-27939 (Patent Document 1) discloses a multilayer ceramic capacitor in which a junction is located between a laminated portion and a side margin portion, and discloses that the magnesium concentration of the junction is higher than that of the laminated portion and the side margin portion, and that the junction is denser than that of the side margin portion.

[0003] Japanese Patent Publication No. 2022-27939

[0004] The multilayer ceramic capacitor disclosed in Japanese Patent Publication No. 2022-27939 (Patent Document 1) had low insulation resistance and dielectric breakdown voltage, and therefore lacked sufficient reliability, because an oxidized region formed by magnesium segregation was located at the junction side end of the internal electrode layer. Furthermore, the segregation of magnesium sometimes reduced mechanical strength and moisture resistance.

[0005] The purpose of this disclosure is to provide a multilayer ceramic capacitor with improved reliability and suppressed reduction in mechanical strength and moisture resistance.

[0006] A multilayer ceramic capacitor according to an embodiment of the present disclosure comprises a laminate having an inner layer in which an inner ceramic layer and an inner electrode layer are alternately laminated, an outer ceramic layer disposed on both sides in the lamination direction of the inner layer, and a side ceramic portion disposed on both sides in the width direction perpendicular to the lamination direction of the inner layer and the outer ceramic layer. The inner ceramic layer, the outer ceramic layer, and the side ceramic portion each contain the same or different perovskite-type compounds. The perovskite-type compound contains barium and at least one of titanium and zirconium. The inner ceramic layer, the outer ceramic layer, and the side ceramic portion have a magnesium concentration of 0.05 moles or less per 100 moles of the total amount of titanium and zirconium in the perovskite-type compound. The inner electrode layer mainly contains nickel. The bonding ratio between the side ceramic portion and the inner electrode layer is 80% or more.

[0007] A multilayer ceramic capacitor according to another embodiment of the present disclosure comprises a laminate having an inner layer in which an inner ceramic layer and an inner electrode layer are alternately laminated, an outer ceramic layer disposed on both sides in the lamination direction of the inner layer, and a side ceramic portion disposed on both sides in the width direction perpendicular to the lamination direction of the inner layer and the outer ceramic layer. The inner ceramic layer, the outer ceramic layer, and the side ceramic portion contain the same or different perovskite-type compounds. The perovskite-type compound contains barium and at least one of titanium and zirconium. The inner ceramic layer, the outer ceramic layer, and the side ceramic portion do not contain magnesium. The inner electrode layer contains nickel as its main component. The bonding ratio between the side ceramic portion and the inner electrode layer is 80% or more.

[0008] According to this disclosure, it is possible to provide multilayer ceramic capacitors with improved reliability and suppressed degradation of mechanical strength and moisture resistance.

[0009] This is a perspective view showing the appearance of a multilayer ceramic capacitor according to the embodiment. This is a cross-sectional view of the multilayer ceramic capacitor shown in Figure 1, taken from the direction of the arrow II-II. This is a cross-sectional view of the multilayer ceramic capacitor shown in Figure 1, taken from the direction of the arrow III-III. This is a schematic cross-sectional view illustrating the bonding ratio between the side ceramic portion and the internal electrode layer.

[0010] <First Embodiment> The multilayer ceramic capacitor of the first embodiment (hereinafter also referred to as the first multilayer ceramic capacitor) will be described with reference to Figures 1 to 3. Figure 1 is a perspective view showing the external appearance of the first multilayer ceramic capacitor. Figure 2 is a cross-sectional view of the first multilayer ceramic capacitor in Figure 1, taken from the direction of the arrow II-II. Figure 3 is a cross-sectional view of the first multilayer ceramic capacitor in Figure 1, taken from the direction of the arrow III-III.

[0011] The first multilayer ceramic capacitor 100 shown in Figures 1 to 3 comprises a laminate 110 and an external electrode 120. The laminate 110 has an inner layer portion 150 including an internal ceramic layer 130 and an internal electrode layer 140 that are alternately stacked one layer at a time along the stacking direction T, and an external ceramic layer 160 arranged on both sides of the inner layer portion 150 in the stacking direction T. The external ceramic layer 160 includes a first external ceramic layer 160A and a second external ceramic layer 160B.

[0012] The laminate 110 has side ceramic portions 170 arranged on both sides in the width direction W perpendicular to the lamination direction T. The side ceramic portions 170 include a first side ceramic portion 170A and a second side ceramic portion 170B.

[0013] The laminate 110 has a first main surface 161 and a second main surface 162 that are opposite each other in the stacking direction T, a first side surface 171 and a second side surface 172 that are opposite each other in the width direction W which is perpendicular to the stacking direction T, and a first end surface 181 and a second end surface 182 that are opposite each other in the length direction L which is perpendicular to both the stacking direction T and the width direction W. The laminate 110 can be divided into an inner layer 150, an outer ceramic layer 160, and a side ceramic portion 170. The inner ceramic layer 130, the outer ceramic layer 160, and the side ceramic portion 170 are collectively referred to as the ceramic portion.

[0014] The internal electrode layer 140 includes a first internal electrode layer 140A connected to the first external electrode 120A and a second internal electrode layer 140B connected to the second external electrode 120B. When the first internal electrode layer 140A and the second internal electrode layer 140B face each other via the internal ceramic layer 130, one capacitor is formed. The first multilayer ceramic capacitor 100 can be said to be one in which a plurality of capacitors are connected in parallel via the first external electrode 120A and the second external electrode 120B. As shown in FIG. 3, the positions of the end faces at both ends in the width direction W of the internal electrode layer 140 may be the same or substantially the same. In the cross section shown in FIG. 3, based on the positions of the end faces at both ends in the width direction W of the internal electrode layer 140, the side ceramic portion 170, the inner layer portion 150, and the external ceramic layer 160 can be distinguished. The number of stacked internal ceramic layers 130 may be, for example, 200 or more and 1000 or less. The number of stacked internal electrode layers 140 may be, for example, 200 or more and 1000 or less.

[0015] The ceramic portion is manufactured using a ceramic material. The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 contain, as a main component, a perovskite-type compound that is the same as or different from each other. The perovskite-type compound may be a perovskite-type compound represented by the formula: ABO ３ [wherein A includes barium (Ba), B includes at least one of titanium (Ti) and zirconium (Zr), and O is an oxygen atom].

[0016] Examples of the perovskite-type compound include perovskite-type compounds of the barium titanate (BaTiO ３ ) system and perovskite-type compounds of the barium zirconate (BaZrO ３ ) system. The perovskite-type compound of the BaTiO ３ system means, for example, BaTiO ３ , and at least one of Ba ２＋ and Ti ４＋ in BaTiO ３ is Ca ２＋ and Zr ４＋These are perovskite-type compounds substituted with other ions, such as BaZrO. ３ Examples of perovskite-type compounds in this system include BaZrO ３ , and BaZrO ３ Ba ２＋ and Zr ４＋ At least one of them is Ca ２＋ and Zr ４＋ These include perovskite-type compounds substituted with other ions, etc.

[0017] The content of the perovskite-type compound in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 may be, for example, 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170, respectively.

[0018] The perovskite-type compound contained in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 is ABO ３ In the case of a perovskite-type compound represented by , the ABO contained in the inner ceramic layer 130, outer ceramic layer 160, and side ceramic portion 170 ３ The molar ratio A / B of the A-site component to the B-site component of the perovskite-type compound represented by is preferably 1.004 or more and 1.010 or less. By keeping A / B within the above range, grain growth during firing can be suppressed and the generation of coarse particles can be suppressed.

[0019] In the first ceramic capacitor, the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 contain magnesium (Mg). The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 have a Mg concentration (hereinafter also referred to as Mg concentration) of 0.05 mol parts or less per 100 mol parts of the total amount of Ti and Zr in the perovskite-type compound. Mg contained in the entire ceramic portion of a multilayer ceramic capacitor tends to segregate in the internal electrode layer. Therefore, it has been found that setting the Mg concentration of the ceramic portion within the above range makes it easier to suppress the formation of Mg segregation in the internal electrode layer, and as a result, insulation resistance, dielectric breakdown voltage, and reliability tend to improve. The Mg concentration may be, for example, 0.03 mol parts or less or 0.01 mol parts or less, or greater than 0 mol parts.

[0020] The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 may further contain rare earth elements (Re). When the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 further contain rare earth elements, the perovskite-type compound has some elements in its crystal lattice that are ions of rare earth elements (Re). ３＋ It may be a perovskite-type compound substituted with .

[0021] The rare earth elements may include at least one selected from the group consisting of scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). The inner layer 150, the outer ceramic layer 160, and the side ceramic layers 170 preferably contain at least one selected from the group consisting of Dy, Y, Gd, Tb, Ho, and Er, and more preferably contain Dy.

[0022] The content of rare earth elements in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic part 170 may be 0.5 mol part or more and 3.0 mol parts or less, preferably 1.0 mol part or more and 2.0 mol parts or less, and more preferably 1.5 mol parts or more and 1.7 mol parts or less, respectively, with respect to 100 mol parts of the perovskite-type compound contained in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic part 170.

[0023] When the internal ceramic layer 130 contains Dy, the content of Dy may be 1.5 mol parts or more and 1.7 mol parts or less with respect to 100 mol parts of the perovskite-type compound contained in the internal ceramic layer 130.

[0024] When the external ceramic layer 160 and the side ceramic part 170 contain Dy, the content of Dy may be 1.5 mol parts or more and 1.7 mol parts or less, respectively, with respect to 100 mol parts of the perovskite-type compound contained in the external ceramic layer 160 and the side ceramic part 170.

[0025] The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic part 170 may further contain at least one selected from the group consisting of silicon (Si), aluminum (Al), manganese (Mn), nickel (Ni), iron (Fe), copper (Cu), and vanadium (V) as other elements. By containing these other elements, the densification of the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic part 170 can be controlled in the firing process.

[0026] The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 preferably further contain Mn, Si, and Al from the viewpoint of airtightness. When the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 further contain Mn, Si, and Al, the contents of Mn, Si, and Al in the external ceramic layer 160 and the side ceramic portion 170 can be made larger than the contents of Mn, Si, and Al in the internal ceramic layer 130, respectively. Thereby, the difference in airtightness between the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 tends to become small.

[0027] In the external ceramic layer 160 and the side ceramic portion 170, the ratio of the content of Mn to the total content of Mn, Si, and Al [Mn / (Mn + Si + Al)] can be, for example, 0.09 or more and 0.42 or less.

[0028] When the internal ceramic layer 130 further contains Mn, Si, and Al, the content of Mn can be, for example, 0.1 mole part or more and 0.2 mole part or less, the content of Si can be, for example, 1.0 mole part or more and 1.4 mole part or less, and the content of Al can be, for example, 0.06 mole part or more and 0.1 mole part or less with respect to 100 mole parts of the perovskite-type compound.

[0029] When the external ceramic layer 160 and the side ceramic portion 170 further contain Mn, Si, and Al, the content of Mn can be, for example, 0.2 mole part or more and 1.0 mole part or less, the content of Si can be, for example, 1.0 mole part or more and 2.6 mole part or less, and the content of Al can be, for example, 0.08 mole part or more and 0.27 mole part or less with respect to 100 mole parts of the perovskite-type compound.

[0030] The internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 preferably further contain Ni. If the internal ceramic layer 130 further contains Ni, the Ni content may be, for example, 1.3 moles to 1.7 moles per 100 moles of the perovskite-type compound. If the external ceramic layer 160 and the side ceramic portion 170 further contain Ni, the Ni content may be, for example, 0.4 moles to 0.6 moles per 100 moles of the perovskite-type compound.

[0031] The content of Mg, rare earth elements, and other elements in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 can be determined from the mixing ratio of the starting materials. Furthermore, the content of Mg, rare earth elements, and other elements in the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 can be quantified, for example, by X-ray fluorescence analysis (XRF), inductively coupled plasma emission spectroscopy (ICP-AES), or energy-dispersive X-ray spectroscopy (EDX). When quantifying by EDX, for example, it can be done using a scanning transmission electron microscope (STEM / EDX) at a magnification of 150,000x.

[0032] It has been discovered that when the ceramic part contains Mg, the factor that reduces the mechanical strength and moisture resistance of multilayer ceramic capacitors is the pores (gaps or holes) formed at the edges of the internal electrode layer on the side ceramic part side. It is thought that these pores are formed during the manufacturing process of multilayer ceramic capacitors due to shrinkage of the internal electrode layer during the sintering and annealing processes, or due to the elimination of elemental segregation within the internal electrode layer. When the ceramic part contains Mg, it is presumed that Mg segregates in the internal electrode layer, and during the manufacturing process of multilayer ceramic capacitors, Ni-Mg segregation is formed in the internal electrode layer by the firing process, and then the Ni-Mg segregation disappears during the subsequent annealing process, making it easier for pores to form. When pores are formed at the edges of the internal electrode layer on the side ceramic part side, the adhesion between the internal electrode layer and the side ceramic part decreases, which tends to reduce mechanical strength, and moisture tends to penetrate the internal electrode layer, reducing moisture resistance. The first multilayer ceramic capacitor has an Mg concentration of 0.05 molar parts or less, making it less prone to Ni-Mg segregation, and thus less prone to pore formation in the internal electrode layer even after annealing. As a result, pores are less likely to form at the edges of the internal electrode layer on the side ceramic portion, which helps to suppress the decrease in mechanical strength and moisture resistance.

[0033] The bonding ratio between the side ceramic portion 170 and the internal electrode layer 140 is 80% or more. The bonding ratio is determined as follows. First, as shown in Figure 4, a cross-section in the width direction W perpendicular to the stacking direction T of the multilayer ceramic capacitor is photographed using a scanning electron microscope (SEM). The SEM image is taken so that one end of the side ceramic portion side of 40 internal electrode layers 140 is included in one field of view. Note that the number of stacks is omitted in Figure 4. Next, the number of internal electrode layers 140P in which pores P are formed at the end of the internal electrode layer 140 on the side ceramic portion side is counted in the photographed image. The bonding ratio is calculated by subtracting the number of internal electrode layers in which pores were confirmed from the number of internal electrode layers observed, dividing the result by the number of internal electrode layers observed, and multiplying the result by 100. The bonding ratio is determined by observing a total of 200 internal electrode layers 140, including the internal electrode layer in the SEM image of the region containing one of the outermost internal electrode layers 140 in the stacking direction T (hereinafter also referred to as the outermost region) and the SEM image of the region containing the internal electrode layer 140 located in the center of the stacking direction T (hereinafter also referred to as the central region).

[0034] A bonding rate of 80% or more tends to improve insulation resistance, dielectric breakdown voltage, and reliability, while suppressing the decrease in mechanical strength and moisture resistance. To achieve a bonding rate of 80% or more, for example, the Mg concentration, firing conditions (e.g., firing temperature, firing time, heating rate, etc.) and annealing conditions (e.g., annealing temperature, annealing time, heating rate, etc.) can be adjusted.

[0035] When side ceramic portions are present on both sides of the inner layer (for example, when a first side ceramic portion 170A and a second side ceramic portion 170B are present), the bonding ratio is the bonding ratio between either side ceramic portion and the internal electrode layer. When side ceramic portions are present on both sides of the inner layer, the bonding ratio between either side ceramic portion and the internal electrode layer of the multilayer ceramic capacitor may be 80% or more, and preferably the bonding ratio between both side ceramic portions and the internal electrode layer is 80% or more.

[0036] The bonding ratio is preferably 90% or more from the viewpoint of insulation resistance, dielectric breakdown voltage, reliability, mechanical strength, and moisture resistance.

[0037] The absolute difference between the number of pores in the outermost region and the number of pores in the central region is preferably 10 or less from the viewpoint of insulation resistance, dielectric breakdown voltage, reliability, mechanical strength, and moisture resistance. The number of pores in the outermost region and the number of pores in the central region can be determined from the images of the outermost region and the central region described above. The number of pores refers to the number of internal electrode layers 140P in which pores P are formed at the end of the internal electrode layer 140 on the side ceramic portion side. The number of pores in the outermost region and the central region was determined by observing 40 internal electrode layers from SEM images of the region including one of the outermost internal electrode layers 140 in the stacking direction T and the region including the central internal electrode layer 140 in the stacking direction T, and counting the number of internal electrode layers 140P in which pores P are formed at the end of the internal electrode layer 140 on the side ceramic portion side.

[0038] The internal electrode layer 140 mainly contains Ni. The main component is the component that has the largest mass content among the constituent components. The internal electrode layer 140 may be an alloy containing Ni. The internal electrode layer 140 may further contain tin (Sn).

[0039] The internal electrode layer may or may not contain Mg. The internal electrode layer 140 may contain dielectric particles of the same composition as the dielectric ceramics contained in the internal ceramic layer 130 as a co-material, or it may contain dielectric particles of a different composition. The co-material may or may not contain Mg. When the internal electrode layer contains a co-material, the melting point of the internal electrode layer tends to rise, and the decrease in coverage during firing tends to be suppressed.

[0040] The internal ceramic layer 130 may have a thickness of, for example, 0.3 μm to 0.6 μm. The thickness of the external ceramic layer may be, for example, 12 μm to 45 μm. The thickness of the side ceramic portion may be, for example, 8 μm to 25 μm. When the ceramic portion has a thickness within the above range, the particle size and density tend to become uniform during the firing process, and the difference in density within the ceramic portion tends to become smaller.

[0041] The thickness of the internal electrode layer 140 in the lamination direction T may be, for example, 0.2 μm or more and 0.5 μm or less. When the thickness of the internal electrode layer 140 in the lamination direction T is within the above range, the common material tends to reach the edges in the width direction more easily during the firing process.

[0042] The laminate 110 may further have end face ceramic portions 180 arranged on both sides in the length direction L, which is perpendicular to both the lamination direction T and the width direction W. The end face ceramic portion 180 has a first end face ceramic portion 180A and a second end face ceramic portion 180B. The thickness of the end face ceramic portion 180 may be, for example, 15 μm or more and 50 μm or less. The composition of the end face ceramic portion 180 is the same as the composition description for the outer ceramic layer 160 and the side ceramic portion 170.

[0043] In this specification, the thicknesses of the internal ceramic layer 130, the internal electrode layer 140, the external ceramic layer 160, the side ceramic portion 170, and the end ceramic portion 180 are measured in a scanning electron microscope (hereinafter sometimes abbreviated as SEM) observation image of the cross-section of the laminate 110 in the stacking direction T.

[0044] The internal ceramic layer 130 may contain multiple grains. A grain is a particle surrounded by a grain boundary and is also called a crystal grain.

[0045] The particle sizes of multiple grains can be measured using a scanning electron microscope (SEM). In this specification, the particle size of a single grain refers to the diameter of a circle having an area equal to the area of ​​the grain's cross-section in an SEM observation image of a cross-section parallel to the stacking direction T and width direction W of the inner layer 150 (hereinafter also referred to as the area circle equivalent diameter). In this specification, in the particle size distribution of the area circle equivalent diameters of multiple grains measured from an SEM observation image of a cross-section parallel to the stacking direction T and width direction W of the inner layer 150, the particle size that accumulates to 50% based on area is defined as D50, and the particle size that accumulates to 99% based on area is defined as D99. The SEM observation image of the above cross-section of the inner layer 150 may be, for example, an SEM observation image at 40,000x magnification. The cumulative particle size distribution of multiple grains is determined from the particle sizes of 200 or more grains. Note that a single SEM image does not need to contain more than 200 grains; it is sufficient if the total number of grains contained in multiple SEM images is 200 or more.

[0046] The inner layer 150 is a cross-section of the laminate 110, and in a cross-section parallel to the lamination direction T and the width direction W, it has a central region 150B, a region near the outer ceramic layer 150A, and a region near the side ceramic portion 150C. The central region 150B, the region near the outer ceramic layer 150A, and the region near the side ceramic portion 150C will be described with reference to Figure 3. The central region 150B is a region located near the center in the lamination direction T and the width direction W in a cross-section parallel to the lamination direction T and the width direction W. The central region 150B may be, for example, a region within a 3.0 μm × 3.0 μm square centered on the intersection of a center line that bisects the inner layer 150 in the lamination direction T and a center line that bisects the inner layer 150 in the width direction W. The region 150A near the outer ceramic layer is the region located in the center of the width direction W of the inner ceramic layer 130 closest to the outer ceramic layer 160 and the inner ceramic layer 130 second closest to the outer ceramic layer 160. The center of the width direction W may be, for example, a region of 1.5 μm on both sides (total width 3.0 μm) from the center line that divides the inner layer 150 in the width direction W. The region 150C near the side ceramic part is the region 3.0 μm inward from the width direction end of the inner electrode layer 140 (i.e., the boundary between the inner layer 150 and the side ceramic part 170), and is located in the center of the stacking direction T. The center of the stacking direction T may be, for example, a region of 1.5 μm on both sides (total thickness 3.0 μm) from the center line that divides the inner layer 150 in the stacking direction T. In Figure 3, only the region 150A near the outer ceramic layer on the first main surface 161 side is shown, but a region 150A near the outer ceramic layer also exists on the second main surface 162 side. The grain size of the grains contained in the region 150A near the outer ceramic layer may be measured from either of the two regions 150A near the outer ceramic layer. Also, in Figure 3, only the region 150C near the side ceramic portion on the second side surface 172 side is shown, but a region 150C near the side ceramic portion also exists on the first side surface 171 side. The grain size of the grains contained in the region 150C near the side ceramic portion may be measured from either of the two regions 150C near the side ceramic portion.

[0047] In the inner layer 150, the sintering behavior during the firing process differs between the central region 150B, the region near the outer ceramic layer 150A, and the region near the side ceramic portion 150C. As a result, the grain size of the grains contained in each region may differ. Specifically, the grain size of the grains contained in the region near the outer ceramic layer 150A or the region near the side ceramic portion 150C tends to be larger than that of the grains contained in the central region 150B.

[0048] The grain D50 in the central region 150B, the region near the outer ceramic layer 150A, and the region near the side ceramic portion 150C is 80 nm to 140 nm, preferably 90 nm to 135 nm, and more preferably 100 nm to 130 nm.

[0049] The D99 / D50 values ​​of the grains in the central region 150B, the region near the outer ceramic layer 150A, and the region near the side ceramic portion 150C are each 1.4 or more and 2.2 or less, preferably 2.1 or less, and more preferably 2.0 or less.

[0050] The grain size is determined by the starting material (e.g., BaTiO) used to fabricate the internal ceramic layer 130. ３ The above range can be achieved by selecting the particle size and composition of the powder, adjusting the content of rare earth elements and other elements, and adjusting the firing temperature and heating rate in the firing process of the multilayer ceramic capacitor manufacturing method described later.

[0051] The external electrodes 120 are provided on the surface of the laminate 110. The external electrodes 120 are arranged on both sides in the longitudinal direction L perpendicular to the stacking direction T of the laminate 110 and are connected to the internal electrode layer 140. In the first multilayer ceramic capacitor 100, the external electrodes 120 include a first external electrode 120A and a second external electrode 120B.

[0052] The first external electrode 120A is formed on the first end face 181 of the laminate 110 so as to be electrically connected to the first internal electrode layer 140A. The first external electrode 120A extends from the first end face 181 to the first main surface 161 and the second main surface 162, and to the first side surface 171 and the second side surface 172. The second external electrode 120B is formed on the second end face 182 of the laminate 110 so as to be electrically connected to the second internal electrode layer 140B. The second external electrode 120B extends from the second end face 182 to the first main surface 161 and the second main surface 162, and to the first side surface 171 and the second side surface 172.

[0053] The first external electrode 120A and the second external electrode 120B each have, for example, a base electrode layer and a plating layer disposed on the base electrode layer. The base electrode layer includes, for example, at least one selected from a sintered body layer, a conductive resin layer, and a metal thin film layer.

[0054] The sintered body layer is formed by baking a paste containing glass powder and metal powder, and includes a glass portion and a metal portion. The glass constituting the glass portion is B ２ O ３ -SiO ２ - Examples include BaO-based glass. The metal constituting the metal part may be at least one selected from Ni, Cu, and Ag, or an alloy containing such metal. Multiple sintered layers may be formed with different components. Furthermore, the sintered layers may be fired simultaneously with the laminate in the manufacturing method described later, or they may be baked on after the laminate has been fired.

[0055] The conductive resin layer comprises conductive particles, such as metal nanoparticles, and a resin portion. The metal constituting the metal nanoparticles may be at least one selected from Ni, Cu, and Ag, or an alloy containing these metals. The resin constituting the resin portion may be an epoxy-based thermosetting resin. The conductive resin layer may be formed in multiple layers of different components.

[0056] The metal thin film layer is a layer with a thickness of 1 μm or less, formed by a thin film formation method such as sputtering or vapor deposition, in which metal nanoparticles are deposited. Examples of metals constituting the metal thin film layer include at least one selected from Ni, Cu, Ag, and Au, or alloys containing these metals. Multiple metal thin film layers may be formed with different components.

[0057] Examples of metals constituting the plating layer include at least one selected from Ni, Cu, Ag, Au, and tin (Sn), or alloys containing such metals. The plating layer may be formed in multiple layers with different components.

[0058] The first external electrode 120A and the second external electrode 120B may each be a plating layer directly provided on the laminate 110 and directly connected to the corresponding internal electrode layer 140 described above.

[0059] The first multilayer ceramic capacitor 100 is manufactured, for example, as follows. First, slurries for the internal ceramic layer, the external ceramic layer, and the side ceramic portion are prepared to produce the green sheets for the internal ceramic layer, the external ceramic layer, and the side ceramic portion, respectively. Each element can be mixed in an oxide or carbonate state to achieve the composition of the internal ceramic layer 130, the external ceramic layer 160, and the side ceramic portion 170 as described above.

[0060] The outer ceramic layer and the side ceramic portion can be formulated to have higher amounts of Mn, Si, and Al compared to the inner ceramic layer from the viewpoint of density. In the outer ceramic layer 160 and the side ceramic portion 170, the content of Si, Mn, and Al can be increased in that order (Si > Mn > Al). The composition values ​​of each slurry can be adjusted according to the chip size of the first multilayer ceramic capacitor 100. The composition of each slurry can be adjusted so that it does not contain Mg, or it can be adjusted to contain Mg.

[0061] The slurry is formed into a sheet on a carrier film using a die coater, gravure coater, or microgravure coater, thereby forming a green sheet for the internal ceramic layer, a green sheet for the external ceramic layer, and a green sheet for the side ceramic portion.

[0062] Next, a conductive paste mainly composed of Ni is screen printed onto a green sheet for the internal ceramic layer to form a conductive paste film (conductor pattern) that will serve as the internal electrode. The green sheets for the internal ceramic layer, on which the conductive paste film is formed, are stacked so that the ends of the conductive paste film are drawn in alternating directions to create a laminate for the inner layer. A co-material can be included in the conductive paste. The co-material may or may not contain Mg.

[0063] Next, green sheets for the outer ceramic layer are stacked above and below the laminate for the inner layer, sandwiching it between them. Then, the laminate for the inner layer, on which the green sheets for the outer ceramic layer are stacked, is pressed in the stacking direction by a hydrostatic press or a rigid press, and after being compressed, it is cut along cutting lines parallel to the length and width directions to obtain a predetermined product size. The cross-sections in the thickness direction on both sides of the width direction formed by this cutting become the end faces at both ends of the internal electrode layer in the width direction W. Green sheets for the side ceramic parts are attached to the sides where the internal electrode layer is exposed, located on both sides of the width direction. In this way, an unfired laminate that will become the laminate 110 of the first multilayer ceramic capacitor 100 is formed.

[0064] The unfired laminate is degreased and then N ２ In an atmosphere, the laminate is heat-treated at a predetermined temperature, and the binder is burned off. After that, the unfired laminate is N ２ -H ２ -H ２ The material is heated to the firing temperature in a reducing atmosphere consisting of oxygen gas, for example, at a heating rate of 15°C / min or more, and then fired. The firing temperature may be, for example, 1100°C to 1300°C.

[0065] Next, an annealing treatment is performed. The annealing treatment is preferable to the firing treatment as it has a lower maximum temperature and is performed in a weakly reducing atmosphere. The green sheets and conductive paste film for the internal ceramic layer, external ceramic layer, and side ceramic portion are as follows: the green sheet for the internal ceramic layer becomes the internal ceramic layer 130, the green sheet for the external ceramic layer becomes the external ceramic layer 160, the green sheet for the side ceramic portion becomes the side ceramic portion 170, and the conductive paste film becomes the internal electrode layer 140.

[0066] Next, after a base electrode layer is formed on the surface of the laminate 110, a plating layer is formed by electroplating so as to cover the base electrode layer.

[0067] The first multilayer ceramic capacitor 100 is manufactured through the above-described series of processes.

[0068] The dimensions of the first multilayer ceramic capacitor 100 are not particularly limited, but for example, the length L dimension may be 0.18 mm or more and 1.3 mm or less, the width W dimension may be 0.08 mm or more and 0.8 mm or less, and the stacking direction T dimension may be 0.08 mm or more and 0.8 mm or less.

[0069] The first multilayer ceramic capacitor 100 can be a two-terminal capacitor.

[0070] <Second Embodiment> The second embodiment of the multilayer ceramic capacitor (hereinafter also referred to as the second multilayer ceramic capacitor) will be described mainly in terms of its differences from the first multilayer ceramic capacitor. The second multilayer ceramic capacitor does not contain Mg in its internal ceramic layer, external ceramic layer, and side ceramic portion. Because the internal ceramic layer, external ceramic layer, and side ceramic portion do not contain Mg, segregation of Mg concentration in the internal electrode layer is more easily suppressed, and reliability tends to be improved.

[0071] In the second multilayer ceramic capacitor, segregation of Mg concentration in the internal electrode layer is more easily suppressed, which in turn suppresses the formation of pores at the edges of the internal electrode layer on the side ceramic portion, making it easier to increase the bonding ratio. As a result, the second multilayer ceramic capacitor tends to exhibit less reduction in mechanical strength and moisture resistance.

[0072] To ensure that the internal ceramic layer, external ceramic layer, and side ceramic portion do not contain Mg, for example, methods can be used to prepare the slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion without containing Mg, and a method can be used to prepare the paste for the internal electrode layer without using a co-material containing Mg.

[0073] [Reliability Evaluation] Fifty multilayer ceramic capacitors were prepared, and their reliability was evaluated by high-temperature load testing at an ambient temperature of 125°C, a voltage of 16–32 V / μm, and a test duration of 10 hours. Capacitors that short-circuited after the test were determined to be faulty. In Table 1, ○ indicates that one or fewer capacitors failed, and × indicates that more than one capacitor failed.

[0074] [Evaluation of Humidity Resistance] Fifty multilayer ceramic capacitors were prepared, and their hydrogen ingress suppression ability was evaluated by a humidity resistance test conducted at an ambient temperature of 85°C, relative humidity of 85% RH, a voltage of 13-25 V / μm, and a test duration of 1000 hours. Failure was determined when the insulation resistance fell to 1 / 10 or less of the initial value. In Table 1, ◎ indicates 0 failures, ○ indicates 1 failure, △ indicates 2-4 failures, and × indicates 5 or more failures.

[0075] [Evaluation of Bonding Ratio] A cross-section of the multilayer ceramic capacitor in the width direction perpendicular to the stacking direction was imaged using a scanning electron microscope (SEM) so that one end of the side ceramic portion of 40 internal electrode layers was included in a single field of view. In the captured images, the number of internal electrode layers in which pores were formed at the end of the side ceramic portion was counted. The total number of internal electrode layers observed in the SEM images, including the image of the region containing the outermost internal electrode layer in the stacking direction and the image of the region containing the internal electrode layer located in the center of the stacking direction, was 200. The bonding ratio was calculated by subtracting the number of internal electrode layers in which pores were confirmed from the number of observed internal electrode layers (200), dividing this value by the number of observed internal electrode layers, and multiplying the result by 100. Furthermore, the difference between the number of pores in the outermost region and the number of pores in the central region was calculated.

[0076] <Example 1> A multilayer ceramic capacitor was fabricated according to the manufacturing method described above. BaTiO was used as the perovskite compound. ３ Powder was used. In addition, the slurry for the internal ceramic layer was BaTiO ３ BaTiO2 is prepared in oxide or carbonate form, with the following concentrations per 100 moles: Dy: 1.5-1.7 mol, Mn: 0.1-0.2 mol, Ni: 1.3-1.7 mol, Si: 1.0-1.4 mol, Al: 0.06-0.1 mol. ３ It was prepared by mixing with powder. The slurry for the outer ceramic layer and the slurry for the side ceramic part were BaTiO ３ BaTiO2 is prepared in oxide or carbonate form, with the following concentrations per 100 moles: Dy: 1.5-1.7 mol, Mn: 0.2-1.0 mol, Si: 1.3-2.5 mol, Al: 0.1-0.27 mol, Ni: 0.4-0.6 mol. ３ The slurry was prepared by mixing with powder. The slurry for the outer ceramic layer and the slurry for the side ceramic parts were formulated to have higher amounts of Mn, Si, and Al compared to the slurry for the inner ceramic layer. In addition, both the outer ceramic layer slurry and the slurry for the side ceramic parts were formulated so that the content of Si, Mn, and Al increased in that order (Si > Mn > Al).

[0077] The slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion were all made without Mg. A co-material containing Mg was added to the internal electrode paste for forming the internal electrode, which is mainly composed of Ni. The resulting multilayer ceramic capacitor had dimensions of 0.6 mm in the L direction, and dimensions of 0.3 mm in both the width (W) and thickness (T) directions. The thickness of the external ceramic layer was 18 μm, the internal ceramic layer was 0.5 μm, the side ceramic portion was 15 μm, and the internal electrode layer was 0.37 μm. Table 1 shows the BaTiO in the slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion. ３ The content of Mn, Si, Al, and Ni per 100 moles (moles) is shown. Furthermore, after removing the external electrodes of the fabricated multilayer ceramic capacitor, the internal ceramic layer (which was not separated from the Ni internal electrodes because separation was difficult), the external ceramic layer, and the side ceramic portion were extracted from the laminate (ceramic body) by polishing, dissolved with acid, and subjected to ICP emission spectroscopy analysis. Table 1 shows the BaTiO in the internal ceramic layer, external ceramic layer, and side ceramic portion. ３ The Mg content (in moles) is shown relative to 100 moles of the total amount of Ti and Zr in the material. Table 2 shows the evaluation results for bonding efficiency, the absolute value of the difference between the number of pores in the outermost region and the number of pores in the central region, reliability, and moisture resistance.

[0078] <Examples 2-10> In the same manner as in Example 1, the dimension in the L direction was 1.0 mm, and the dimensions in the width direction W and the thickness direction T were both 0.5 mm. The thickness of the outer ceramic layer was 32 μm, the thickness of the inner ceramic layer was 0.51 μm, the thickness of the side ceramic portion was 17 μm, and the thickness of the inner electrode layer was 0.45 μm. In the inner ceramic layer, the D50 of the grains near the outer ceramic layer was 126.0 nm, the D99 was 249.6 nm, and the D99 / D50 was 1.98; the D50 of the grains in the central region was 115.3 nm, the D99 was 216.3 nm, and the D99 / D50 was 1.88; and the D50 of the grains near the side ceramic portion was 126.6 nm, the D99 was 278.8 nm, and the D99 / D50 was 2.20. Table 1 shows the BaTiO in the slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion. ３ The content of Mn, Si, Al, and Ni per 100 moles (in moles) is shown. The Mg concentration is shown in Table 1, and the results are shown in Table 2.

[0079] <Comparative Example 1> In the same manner as in Example 1, the dimension in the L direction was 1.0 mm, and the dimensions in the width direction W and the thickness direction T were both 0.5 mm. The thickness of the outer ceramic layer was 32 μm, the thickness of the inner ceramic layer was 0.51 μm, the thickness of the side ceramic portion was 17 μm, and the thickness of the inner electrode layer was 0.45 μm. In the inner ceramic layer, the D50 of the grains near the outer ceramic layer was 118.0 nm, the D99 was 258.9 nm, and the D99 / D50 was 2.19; the D50 of the grains in the central region was 114.2 nm, the D99 was 203.3 nm, and the D99 / D50 was 1.78; and the D50 of the grains near the side ceramic portion was 128.4 nm, the D99 was 269.5 nm, and the D99 / D50 was 2.10. Table 1 shows the BaTiO in the slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion. ３ The content of Mn, Si, Al, and Ni per 100 moles (in moles) is shown. The Mg concentration is shown in Table 1, and the results are shown in Table 2.

[0080] <Comparative Example 2> In the same manner as in Example 1, the dimension in the L direction was 1.0 mm, and the dimensions in the width direction W and the thickness direction T were both 0.5 mm. The thickness of the outer ceramic layer was 32 μm, the thickness of the inner ceramic layer was 0.51 μm, the thickness of the side ceramic portion was 17 μm, and the thickness of the inner electrode layer was 0.45 μm. In the inner ceramic layer, the D50 of the grains near the outer ceramic layer was 128.4 nm, the D99 was 251.2 nm, and the D99 / D50 was 1.96; the D50 of the grains in the central region was 114.1 nm, the D99 was 210.0 nm, and the D99 / D50 was 1.84; and the D50 of the grains near the side ceramic portion was 118.2 nm, the D99 was 255.9 nm, and the D99 / D50 was 2.16. Table 1 shows the BaTiO in the slurry for the internal ceramic layer, the slurry for the external ceramic layer, and the slurry for the side ceramic portion. ３ The content of Mn, Si, Al, and Ni per 100 moles (in moles) is shown. The Mg concentration is shown in Table 1, and the results are shown in Table 2.

[0081]

[0082]

[0083] As shown in Table 1, the Mg concentration was 0.05 molar parts or less in the internal ceramic layer, external ceramic layer, and side ceramic portion of the multilayer ceramic capacitors fabricated in Examples 1 to 10.

[0084] As shown in Table 2, by increasing the Mn, Si, and Al content of the outer ceramic layer and side ceramic portion compared to the inner ceramic layer, and by setting an appropriate heating rate during the firing process, it was possible to suppress the difference in density between the inner ceramic layer and the outer ceramic layer and side ceramic portion.

[0085] As shown in Table 2, the multilayer ceramic capacitors of this disclosure can exhibit improved reliability and moisture resistance. This disclosure demonstrates that it is possible to provide multilayer ceramic capacitors with improved reliability and suppressed degradation of mechanical strength and moisture resistance.

[0086] In the description of the embodiments described above, the combinable configurations may be combined with each other.

[0087] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended.

[0088] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0089] [Clause 1] A multilayer ceramic capacitor comprising: an inner layer in which an inner ceramic layer and an inner electrode layer are alternately stacked; an outer ceramic layer disposed on both sides in the stacking direction of the inner layer; and a side ceramic portion disposed on both sides in the width direction perpendicular to the stacking direction of the inner layer and the outer ceramic layer, wherein the inner ceramic layer, the outer ceramic layer and the side ceramic portion each contain the same or different perovskite-type compounds, the perovskite-type compound each contains barium and at least one of titanium and zirconium, the inner ceramic layer, the outer ceramic layer and the side ceramic portion each have a magnesium concentration of 0.05 moles or less per 100 moles of the total amount of titanium and zirconium in the perovskite-type compound, the inner electrode layer mainly contains nickel, and the bonding rate between the side ceramic portion and the inner electrode layer is 80% or more. [Clause 2] The multilayer ceramic capacitor according to Clause 1, wherein the inner electrode layer contains magnesium. [Clause 3] The multilayer ceramic capacitor according to Clause 1 or 2, wherein the internal ceramic layer, the external ceramic layer, and the side ceramic portion further contain dysprosium. [Clause 4] The multilayer ceramic capacitor according to any one of Clauses 1 to 3, wherein the internal ceramic layer, the external ceramic layer, and the side ceramic portion further contain manganese, silicon, and aluminum. [Clause 5] The multilayer ceramic capacitor according to Clause 4, wherein the manganese content, silicon content, and aluminum content in the external ceramic layer and the side ceramic portion are each greater than the manganese content, silicon content, and aluminum content in the internal ceramic layer. [Clause 6] The multilayer ceramic capacitor according to Clause 4 or 5, wherein the ratio of the manganese content to the total manganese, silicon, and aluminum content in the external ceramic layer and the side ceramic portion is 0.09 or more and 0.42 or less. [Clause 7] The multilayer ceramic capacitor according to any one of Clauses 1 to 6, wherein the bonding rate between the side ceramic portion and the internal electrode layer is 90% or more.[Clause 8] The multilayer ceramic capacitor according to any one of Clauses 1 to 7, wherein the absolute difference between the number of pores in a region including one of the outermost internal electrode layers in the stacking direction and the number of pores in a region including the internal electrode layer located at the center of the stacking direction is 10 or less. [Clause 9] The multilayer ceramic capacitor according to any one of Clauses 1 to 8, wherein the thickness of the internal ceramic layer is 0.3 μm or more and 0.6 μm or less. [Clause 10] The multilayer ceramic capacitor according to any one of Clauses 1 to 9, wherein the internal ceramic layer contains a plurality of grains, and when the particle size that accounts for 50% of the area-based cumulative particle size distribution of the plurality of grains is defined as D50, D50 is 80 nm or more and 140 nm or less. [Clause 11] The multilayer ceramic capacitor according to Clause 10, wherein in the particle size distribution of the area circle equivalent diameter of the plurality of grains, when the particle size that accounts for 50% of the cumulative area is defined as D50 and the particle size that accounts for 99% of the cumulative area is defined as D99, D99 / D50 is 1.4 or more and 2.2 or less. [Clause 12] A multilayer ceramic capacitor comprising: an inner layer portion in which an inner ceramic layer and an inner electrode layer are alternately stacked; an outer ceramic layer disposed on both sides in the stacking direction of the inner layer portion; and a side ceramic portion disposed on both sides in the width direction perpendicular to the stacking direction of the inner layer portion and the outer ceramic layer, wherein the inner ceramic layer, the outer ceramic layer and the side ceramic portion each contain the same or different perovskite-type compounds, the perovskite-type compound each contains barium and at least one of titanium and zirconium, the inner ceramic layer, the outer ceramic layer and the side ceramic portion do not contain magnesium, the inner electrode layer mainly contains nickel, and the bonding rate between the side ceramic portion and the inner electrode layer is 80% or more.

[0090] 100 First multilayer ceramic capacitor, 110 Laminate, 120 External electrode, 120A First external electrode, 120B Second external electrode, 125 Ambient temperature, 130 Internal ceramic layer, 130 nm or more, 140 Internal electrode layer, 140A First internal electrode layer, 140B Second internal electrode layer, 140P Internal electrode layer, 150 Inner layer, 160 External ceramic layer, 160A First external ceramic layer, 160B Second external ceramic layer, 161 First main surface, 162 Second main surface, 170 Side ceramic part, 170A First side ceramic part, 170B Second side ceramic part, 171 First side, 172 Second side, 180 End face ceramic part, 180A First end face ceramic part, 180B Second end face ceramic part, 181 First end face, 182 Second end face.

Claims

1. A multilayer ceramic capacitor comprising: an inner layer portion in which an inner ceramic layer and an inner electrode layer are alternately stacked; an outer ceramic layer disposed on both sides of the stacking direction of the inner layer portion; and a side ceramic portion disposed on both sides of the width direction perpendicular to the stacking direction of the inner layer portion and the outer ceramic layer, wherein the inner ceramic layer, the outer ceramic layer and the side ceramic portion each contain the same or different perovskite-type compounds, the perovskite-type compound each contains barium and at least one of titanium and zirconium, the inner ceramic layer, the outer ceramic layer and the side ceramic portion each have a magnesium concentration of 0.05 moles or less per 100 moles of the total amount of titanium and zirconium in the perovskite-type compound, the inner electrode layer mainly contains nickel, and the bonding rate between the side ceramic portion and the inner electrode layer is 80% or more.

2. The multilayer ceramic capacitor according to claim 1, wherein the internal electrode layer contains magnesium.

3. The multilayer ceramic capacitor according to claim 1 or 2, wherein the internal ceramic layer, the external ceramic layer, and the side ceramic portion further contain dysprosium.

4. The multilayer ceramic capacitor according to any one of claims 1 to 3, wherein the internal ceramic layer, the external ceramic layer, and the side ceramic portion further comprise manganese, silicon, and aluminum.

5. The multilayer ceramic capacitor according to claim 4, wherein the manganese content, silicon content, and aluminum content in the outer ceramic layer and the side ceramic portion are each greater than the manganese content, silicon content, and aluminum content in the inner ceramic layer.

6. The multilayer ceramic capacitor according to claim 4 or 5, wherein the ratio of the manganese content to the total content of manganese, silicon, and aluminum in the outer ceramic layer and the side ceramic portion is 0.09 or more and 0.42 or less.

7. The multilayer ceramic capacitor according to any one of claims 1 to 6, wherein the bonding rate between the side ceramic portion and the internal electrode layer is 90% or more.

8. The multilayer ceramic capacitor according to any one of claims 1 to 7, wherein the absolute difference between the number of pores in a region including one of the outermost internal electrode layers in the stacking direction and the number of pores in a region including the internal electrode layer located at the center of the stacking direction is 10 or less.

9. The multilayer ceramic capacitor according to any one of claims 1 to 8, wherein the thickness of the internal ceramic layer is 0.3 μm or more and 0.6 μm or less.

10. The multilayer ceramic capacitor according to any one of claims 1 to 9, wherein the internal ceramic layer contains a plurality of grains, and when the particle size distribution of the plurality of grains in terms of area circle equivalent diameter is defined as D50, D50 is 80 nm or more and 140 nm or less.

11. In the particle size distribution of the area circle equivalent diameter of the plurality of grains, when the particle size that accounts for 50% of the cumulative area is defined as D50 and the particle size that accounts for 99% of the cumulative area is defined as D99, the ratio of D99 / D50 is 1.4 or more and 2.2 or less, as described in claim 10.

12. A multilayer ceramic capacitor comprising: an inner layer portion in which an inner ceramic layer and an inner electrode layer are alternately stacked; an outer ceramic layer disposed on both sides in the stacking direction of the inner layer portion; and a side ceramic portion disposed on both sides in the width direction perpendicular to the stacking direction of the inner layer portion and the outer ceramic layer, wherein the inner ceramic layer, the outer ceramic layer and the side ceramic portion each contain the same or different perovskite-type compounds, the perovskite-type compounds each contain barium and at least one of titanium and zirconium, the inner ceramic layer, the outer ceramic layer and the side ceramic portion do not contain magnesium, the inner electrode layer mainly contains nickel, and the bonding rate between the side ceramic portion and the inner electrode layer is 80% or more.

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