Multilayer ceramic capacitor

Abstract

This invention provides a multilayer ceramic capacitor with excellent reliability. The multilayer (10) has: a first internal electrode (30A), one end of which is exposed on a third surface (F3); a second internal electrode (30B), one end of which is exposed on a fourth surface (F4); and a dielectric layer (20) containing at least one element of Ca and Sr. In a cross-section in the second direction (W) parallel to the stacking direction (T) and the second direction (W) and located on the third surface (F3) side of the second internal electrode (30B), the total content of Ca and Sr in a region (R15) within 5 μm of the end of the first internal electrode on the fifth surface side in the second direction is greater than the total content of Ca and Sr in a region (R2C) within 5 μm of the center of the first internal electrode in the second direction.

Description

Technical Field

[0001] This invention relates to multilayer ceramic capacitors. Background Technology

[0002] Conventionally, in multilayer ceramic capacitors, the internal electrodes are designed such that the width of the lead-out portion is narrower than the width of the counter portion (a racket shape). It is known that the racket-shaped internal electrodes can extend the path of moisture intrusion from the outside to the internal electrodes, thus improving the moisture resistance of the multilayer ceramic capacitor (e.g., Patent Document 1).

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-94820

[0006] In multilayer ceramic capacitors with racket-shaped internal electrodes, the ends of the internal electrodes are sometimes orthogonal to each other when viewed in the stacking direction. In this case, a decrease in reliability due to electric field concentration may occur near the location where the ends of the internal electrodes are orthogonal when viewed in the stacking direction. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The objective of this invention is to provide a multilayer ceramic capacitor with excellent reliability.

[0009] Methods for solving problems

[0010] To address the aforementioned issues, the multilayer ceramic capacitor of the present invention comprises: a multilayer body having a first and a second surface opposite to each other in a stacking direction, a third and a fourth surface opposite to each other in a first direction orthogonal to the stacking direction, and a fifth and a sixth surface opposite to each other in a second direction orthogonal to the stacking direction and the first direction; a first external electrode disposed on the third surface; and a second external electrode disposed on the fourth surface; the multilayer body further comprising: a first internal electrode, one end of which is exposed on the third surface; and a second internal electrode, one end of which is exposed on the third surface. The fourth surface is exposed; and a dielectric layer containing at least one of Ca and Sr, wherein in a cross-section parallel to the stacking direction and the second direction, and the end of the second internal electrode in the second direction is located closer to the fifth surface than the first internal electrode, the total content of Ca and Sr in the region within 5 μm of the end of the first internal electrode on the fifth surface is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode in the second direction.

[0011] Invention Effects

[0012] It can provide a multilayer ceramic capacitor with excellent reliability. Attached Figure Description

[0013] Figure 1 This is a schematic perspective view of the multilayer ceramic capacitor involved in the embodiment.

[0014] Figure 2 yes Figure 1 Sectional view II-II.

[0015] Figure 3 yes Figure 1 Sectional view III-III.

[0016] Figure 4 yes Figure 1 Sectional view IV-IV.

[0017] Figure 5 yes Figure 1 VV sectional view.

[0018] Figure 6 Is with Figure 4 The corresponding diagram shows the overlap of the internal electrodes.

[0019] Figure 7 yes Figure 1 as well as Figure 6 Sectional view of VIII-VIII.

[0020] Figure 8 yes Figure 1 as well as Figure 6 Sectional view VII-VII.

[0021] Figure 9 yes Figure 1 as well as Figure 6 IX-IX sectional view.

[0022] Figure 10 Is with Figure 6 The corresponding figure is a modified example showing the overlap of the internal electrodes.

[0023] Explanation of reference numerals in the attached figures

[0024] 1: Multilayer ceramic capacitor;

[0025] 10: Layered bodies;

[0026] 20: Dielectric layer;

[0027] 30A: First internal electrode;

[0028] 30B: Second internal electrode;

[0029] 40A: First external electrode;

[0030] 40B: Second external electrode;

[0031] F1: Page 1;

[0032] F2: Page 2;

[0033] F3: Page 3;

[0034] F4: Page 4;

[0035] F5: Page 5;

[0036] F6: Page 6;

[0037] R15: The region within 5 μm of the end of the fifth surface of the first internal electrode;

[0038] R1C2: The region within 5 μm of the center of the first internal electrode in the second direction;

[0039] R1A5: Area A;

[0040] R1A5a: The region inside the second direction when region A is bisected in the second direction;

[0041] R1A5b: The region outside the second direction when region A is bisected in the second direction;

[0042] R13: The region within 5 μm of the end of the third surface of the first internal electrode;

[0043] R1C1: The region within 5 μm of the center of the first internal electrode;

[0044] R1B: Region B;

[0045] R1Ba: The inner region in the first direction when region B is bisected in the first direction;

[0046] R1Bb: The region outside the first direction when region B is bisected in the first direction. Detailed Implementation

[0047] The following is for reference Figures 1-9 The multilayer ceramic capacitor 1 according to an embodiment of the present invention will be described. Although details will be described later, the multilayer ceramic capacitor 1 is a multilayer ceramic capacitor having internal electrodes in the shape of a racket (see reference 1). Figures 4-6 ).

[0048] (Laminated ceramic capacitor 1)

[0049] like Figures 1-3 As shown, the multilayer ceramic capacitor 1 includes a generally rectangular parallelepiped-shaped multilayer 10 and a pair of external electrodes 40 disposed at both ends of the multilayer 10. Furthermore, the multilayer 10 includes an effective portion 11, which includes multiple sets of dielectric layers 20 and internal electrodes 30.

[0050] In the following description, the direction perpendicular to the mounting surface is designated as the stacking direction T, indicating the orientation of the multilayer ceramic capacitor 1. Furthermore, in this embodiment, the direction in which the internal electrode 30 and the dielectric layer 20 are stacked is designated as the stacking direction T.

[0051] Furthermore, the direction in which the pair of external electrodes 40 are disposed is designated as the first direction L. The direction intersecting both the first direction L and the stacking direction T is designated as the second direction W. The direction in the first direction L that separates from the center of the stacked ceramic capacitor 1 in the first direction L is designated as the "outer side in the first direction L", and the direction in the first direction L that approaches the center of the stacked ceramic capacitor 1 in the first direction L is designated as the "inner side in the first direction L". In addition, in the embodiment, the first direction L, the second direction W, and the stacking direction T are orthogonal to each other. In this case, the direction in which the internal electrode 30 and the dielectric layer 20 are stacked may also be designated as the direction horizontal to the mounting surface, and the stacking direction T may be designated as the direction perpendicular to the direction in which the internal electrode 30 and the dielectric layer 20 are stacked.

[0052] The cross section parallel to the stacking direction T and the first direction L of the multilayer ceramic capacitor 1 is designated as the "LT cross section". Figure 2 The cross-section is designated as the LT cross-section passing through the center of the second direction W of the laminated ceramic capacitor 1. The cross-section parallel to the lamination direction T and the second direction W of the laminated ceramic capacitor 1 is designated as the "WT cross-section". Figure 3 The cross-section is designated as the WT cross-section passing through the central portion of the first direction L of the multilayer ceramic capacitor 1. The cross-section parallel to the first direction L and the second direction W of the multilayer ceramic capacitor 1 is designated as the "LW cross-section". Figure 4 The cross-section becomes the LW cross-section that exposes the first internal electrode 30A. Figure 5 The cross-section becomes the LW cross-section that exposes the second internal electrode 30B.

[0053] The dimension of the multilayer ceramic capacitor 1 in the first direction L is, for example, 0.2 mm or more and 5.6 mm or less, preferably 1.6 mm or more and 3.2 mm or less. The dimension of the multilayer ceramic capacitor 1 in the second direction W is, for example, 0.1 mm or more and 5.0 mm or less, preferably 0.8 mm or more and 2.5 mm or less. The dimension of the multilayer ceramic capacitor 1 in the stacking direction T is, for example, 0.1 mm or more and 2.5 mm or less, preferably 0.8 mm or more and 2.5 mm or less. The external dimensions of the multilayer ceramic capacitor 1 can be measured using a micrometer.

[0054] The structure of the multilayer ceramic capacitor 1 is, for example, substantially symmetrical in the second direction W. Therefore, the description will focus on one side of the multilayer ceramic capacitor 1 in the second direction W, and the description of the other side of the multilayer ceramic capacitor 1 in the second direction W will sometimes be omitted.

[0055] (Laminated body 10)

[0056] The laminate 10 has a first surface F1 and a second surface F2 opposite to each other in the lamination direction T, a third surface F3 and a fourth surface F4 opposite to each other in the first direction L, and a fifth surface F5 and a sixth surface F6 opposite to each other in the second direction W.

[0057] The portion where the three outer surfaces of the laminate 10 intersect is designated as a "corner". The portion where the two outer surfaces of the laminate 10 intersect is designated as an "edge". Preferably, the corners and edges of the laminate 10 have rounded corners.

[0058] The laminate 10 has an effective part 11 and an ineffective part 12.

[0059] (Valid part)

[0060] The effective part 11 is the region in which the dielectric layer 20 and the internal electrode 30 are stacked.

[0061] (Dielectric layer)

[0062] The dielectric layer 20 preferably contains perovskite-type compounds such as BaTiO3, CaTiO3, SrTiO3, or CaZrO3 as the main component. The dielectric layer 20 may also contain Mg, Mn, Si, etc., as additives.

[0063] The dielectric layer 20 contains dielectric particles. The dielectric particles, for example, contain core-shell particles. A core-shell particle is a particle having a structure (core-shell structure) in which at least a portion of the byproducts are dissolved in a high concentration on the surface (shell) of the particle, and the byproducts are dissolved in a low concentration or are not dissolved in the core.

[0064] (Internal electrodes)

[0065] The internal electrode 30 has a plurality of first internal electrodes 30A and a plurality of second internal electrodes 30B.

[0066] The first internal electrode 30A and the second internal electrode 30B are arranged alternately, for example. The first internal electrode 30A and the second internal electrode 30B are positioned opposite each other in the stacking direction T, sandwiching a dielectric layer 20. The first internal electrode 30A is exposed onto the third surface F3. The first internal electrode 30A is electrically connected to the first external electrode 40A. The second internal electrode 30B is exposed onto the fourth surface F4. The second internal electrode 30B is electrically connected to the second external electrode 40B. Charge accumulates between the opposing portions of adjacent first internal electrodes 30A and second internal electrodes 30B in the stacking direction T, thereby functioning as a capacitor.

[0067] In addition, the first internal electrode 30A and the second internal electrode 30B are sometimes collectively referred to as "internal electrode 30". The internal electrode closest to the first surface F1 among the multiple internal electrodes 30 can be either the first internal electrode 30A or the second internal electrode 30B.

[0068] The internal electrode 30 may use Ni as the main component, for example. However, it is not limited to this; the internal electrode 30 may also be formed of metallic materials such as Cu, Ag, Pd, Ag-Pd alloys, and Au. In addition, the internal electrode 30 may also contain BT particles (including Ba and Ti particles) as a common material.

[0069] The thickness of the internal electrode 30 is preferably 0.3 μm or more. The diameter of the Ni particles contained in the internal electrode 30 in the direction orthogonal to the stacking direction T is preferably 300 nm or more and 5000 nm or less.

[0070] Regarding the crystallite diameter, for example, if the diameter is long in a direction orthogonal to the thickness in the stacking direction T (e.g., the first direction L), it can be calculated from the crystallite diameter in the first direction L.

[0071] like Figure 4 As shown, the first internal electrode 30A has a first-1 region 31A and a first-2 region 32A. The first-2 region 32A is shorter in the second direction W than the first-1 region 31A and is located on the third surface F3 side closer to the first-1 region 31A. The shape of the first internal electrode 30A is that of a racket.

[0072] The entirety of region 31A 1-1 separates from the outer surface of the laminate 10. The shape of region 31A 1-1 when viewed in the lamination direction T is, for example, approximately rectangular.

[0073] The dimension in the second direction W of region 1-2 32A gradually decreases from the fourth face F4 side toward the third face F3 side, and then becomes fixed. However, it is not limited to this. The dimension in the second direction W of region 1-2 32A may also be fixed across the entire region 1-2 32A, or it may decrease across the entire region 1-2 32A from the fourth face F4 side toward the third face F3 side.

[0074] The average dimension in the second direction W of the portion of the first-second region 32A exposed on the third surface F3 is shorter than the average dimension in the second direction W of the first-first region 31A. Preferably, it is 50% or more and 90% or less relative to the average dimension in the second direction W of the first-first region 31A. The average dimension in the second direction W of the portion of the first-second region 32A exposed on the third surface F3 is set as the average value in the second direction W of the first internal electrode 30A exposed on the same surface. The average dimension in the second direction W of the first-first region 31A is set as the average value in the second direction W of the first internal electrode 30A located at 1 / 2 position in the first direction L of the laminate 10, on the same plane parallel to the lamination direction T and the second direction W.

[0075] The Sn concentration in region 1-2 32A is preferably higher than that in region 1-1 31A. Furthermore, a Sn layer is preferably disposed in region 1-2 32A. Regarding the Sn concentration in region 1-2 32A, it is defined as the average peak intensity at three points in TEM-EDX at a position halfway along the first direction L of region 1-2 32A, parallel to the lamination direction T and the second direction W. Similarly, regarding the Sn concentration in region 1-1 31A, it is defined as the average peak intensity at three points in TEM-EDX at a position halfway along the first direction L of the laminate 10, parallel to the lamination direction T and the second direction W.

[0076] It can be assumed that when the end of the first-second region 32A in the second direction W and the second internal electrode 30B are orthogonal, electric field concentration is likely to occur at the intersection of the end of the first-second region 32A in the second direction W and the second internal electrode 30B, due to the overlap of the internal electrodes 30 with different potentials. However, with this structure, reliability can be improved at the location where electric field concentration is likely to occur.

[0077] Furthermore, not limited to this, a Sn layer may also be disposed in region 1-1 31A. In this case, the thickness of the Sn layer disposed in region 1-2 32A is preferably thicker than the thickness of the Sn layer disposed in region 1-1 31A. If more Sn is included in the internal electrode 30 in order to increase the thickness of the Sn layer disposed in region 1-1 31A, the melting point of the internal electrode 30 will decrease. In the firing process described later, the coverage of the internal electrode 30 may decrease due to over-sintering of the internal electrode 30, and the electrostatic capacitance of the multilayer ceramic capacitor 1 may decrease excessively. By making the thickness of the Sn layer disposed in region 1-1 31A thinner than the thickness of the Sn layer disposed in region 1-2 32A, the influence caused by the Sn layer can be reduced in region 1-1 31A, which is the main region for forming electrostatic capacitance.

[0078] The coverage of region 32A in the first-second region is preferably lower than that of region 31A in the first-first region. The coverage of region 32A in the first-second region is preferably 80% or more. This helps to suppress interlayer delamination. Regarding the coverage, for example, in a plane parallel to the first direction L and the second direction W, in the field of view where the entire first internal electrode 30A is mapped by SEM, it is calculated by dividing the area where the first internal electrode 30A actually exists by the area surrounded by the outline of the first internal electrode 30A.

[0079] Preferably, a Mg region is disposed at the end of the first-second region 32A in the second direction W. Specifically, it is preferable that the Mg region extends from the first-second region 32A in the second direction W.

[0080] The thickness (dimension in the stacking direction T) of the Mg region disposed in the portion near the first-1 region 31A at the end of the first-2 region 32A in the second direction W is preferably thicker than the thickness of the Mg region disposed in the portion near the third surface F3 at the end of the first-2 region 32A in the second direction W.

[0081] The area of ​​the Mg region disposed in the portion of the first-1 region 31A in the second direction W of the first-2 region 32A is preferably larger than the area of ​​the Mg region disposed in the portion of the first-2 region 32A in the second direction W in the portion of the first-2 region 32A near the third surface F3. Specifically, when the first-2 region 32A is divided into 5 equal parts in the first direction L, the Mg regions disposed on the first internal electrode 30A parallel to each cross-section are measured using SEM or the like in the cross-section passing through the end of the first-2 region 32A in the second direction W located at the center of the first direction L, and in the cross-section passing through the end of the first-2 region 32A in the second direction W located next to the region closest to the third surface F3, and the average value is set for each.

[0082] The thickness of the Mg region disposed at the end in the second direction W of the first-2 region 32A is preferably thicker than the thickness of the Mg region disposed at the end in the second direction W of the first-1 region 31A.

[0083] The total number of Mg regions disposed at the end in the second direction W of the first-2 region 32A is preferably greater than the total number of Mg regions disposed at the end in the second direction W of the first-1 region 31A.

[0084] Therefore, when the end of the first-second region 32A in the second direction W is orthogonal to the second internal electrode 30B, the reliability can be improved in the part where electric field concentration is likely to occur.

[0085] The thickness of the Mg region located at the end of the first-second region 32A in the second direction W is set as the average value observed by SEM images of each Mg region at a position halfway along the first direction L of the first-second region 32A, parallel to the stacking direction T and the second direction W. Furthermore, the thickness of the Mg region located at the end of the first-second region 31A in the second direction W is set as the average value observed by SEM images of each Mg region at a position halfway along the first direction L of the laminate 10, parallel to the stacking direction T and the second direction W.

[0086] More specifically, if the multilayer ceramic capacitor 1 is polished in the first direction L, the end of the first-second region 32A in the second direction W will first be exposed in the WT cross-section. In the WT cross-section at this time, the number of Mg regions at the end of the first-second region 32A in the second direction W, relative to the number of the first internal electrode 30A, the thickness of each Mg region in the stacking direction T, the thickness of each Mg region in the second direction W, and the area can be observed.

[0087] If further grinding is performed, in the WT cross-section exposing the first-1 region 31A, the number of Mg regions at the end of the first-1 region 31A in the second direction W, relative to the number of sheets of the first internal electrode 30A, the thickness of each Mg region in the stacking direction T, the thickness of each Mg region in the second direction W, and the area can be observed.

[0088] Furthermore, the thickness in the stacking direction T of the Mg regions within a certain range is set as the average of the values ​​obtained by measuring the maximum dimensions of the Mg regions in the stacking direction T for each Mg region existing within that range. Additionally, the thickness in the second direction W of the Mg regions within a certain range is set as the average of the values ​​obtained by measuring the maximum dimensions of the Mg regions in the second direction W for each Mg region existing within that range.

[0089] The total content of Mg and Mn in the region between region 32A (1-2) and face F5 (5) is preferably greater than the total content of Mg and Mn in the region between region 31A (1-1) and face F5 (5).

[0090] It can be assumed that the sintering of the dielectric layer 20 is prone to incompleteness in the region between the first-second region 32A and the fifth surface F5, and the density of the dielectric layer 20 is prone to decrease. However, according to this structure, the sintering properties of the dielectric layer 20 can be improved in the region between the first-second region 32A and the fifth surface F5, and the density of the dielectric layer 20 can be improved.

[0091] The particle size D50 of the dielectric in the region located within 5 μm of the end of the first-second region 32A in the second direction W is preferably smaller than the particle size D50 of the dielectric in the central region when the region between the first-second region 32A and the second internal electrode 30B opposite in the stacking direction T is divided into 5 equal parts in the second direction W. Regarding the particle size D50, to ensure clear boundaries (grain boundaries) between particles, heat treatment was performed at 1000 °C, and each region was observed using SEM at 20,000x magnification. One hundred particles were randomly extracted from the obtained SEM images, the area of ​​the inner portion of the grain boundary of each particle was calculated, the equivalent circle diameter was calculated, and the particle size D50 was calculated based on these measurements.

[0092] Therefore, when the end of the first-second region 32A in the second direction W and the second internal electrode 30B are approximately orthogonal, the reliability can be improved in the part where electric field concentration is likely to occur.

[0093] For example, in the WT section, when the region sandwiched between the first-2 region 32A and the second-1 region 31B is divided into three equal parts in the second direction W, it is preferable that at least one of the following conditions is met: the particle size D50 of the dielectric particles in the central region of the three regions is larger than the particle size D50 of the dielectric particles in the region located on the fifth face F5 side of the three regions, or larger than the particle size D50 of the dielectric particles in the region located on the sixth face F6 side of the three regions.

[0094] For example, in the LT section, when the region sandwiched between the first-2 region 32A and the second-1 region 31B is divided into three equal parts in the first direction L, it is preferable that at least one of the following conditions is met: the particle size D50 of the dielectric particles in the central region of the three regions is larger than the particle size D50 of the dielectric particles in the region on the third face F3 side of the three regions; or the particle size D50 of the dielectric particles in the region on the fourth face F4 side of the three regions is larger than the particle size D50 of the dielectric particles in the region on the third face F3 side of the three regions.

[0095] Therefore, when the end of the first-second region 32A in the second direction W is approximately orthogonal to the second internal electrode 30B, it is possible to suppress capacitance drop in most of the capacitor formation and improve reliability in areas where electric field concentration is likely to occur.

[0096] like Figure 5 As shown, the second internal electrode 30B has a second-1 region 31B and a second-2 region 32B. The second-2 region 32B is shorter in size in the second direction W than the second-1 region 31B, and is located on the fourth surface F4 side closer to the second surface than the second-1 region 31B.

[0097] The entirety of region 2-1 31B separates from the outer surface of the laminate 10. The shape of region 2-1 31B when viewed in the lamination direction T is, for example, approximately rectangular. Region 2-1 31B and region 1-1 31A are sandwiched between the dielectric layer 20 and are opposite each other in the lamination direction T.

[0098] The dimension of region 32B in the second direction W gradually decreases from the third face F3 side toward the fourth face F4 side, and then becomes fixed. However, it is not limited to this. The dimension of region 32B in the second direction W may also be fixed across the entire region of region 32B, or it may decrease across the entire region of region 32B from the third face F3 side toward the fourth face F4 side.

[0099] The average dimension in the second direction W of the portion of region 2-2 32B exposed on the fourth surface F4 is shorter than the average dimension in the second direction W of region 2-1 31B. Preferably, the difference is 50% or more and 90% or less relative to the average dimension in the second direction W of region 2-1 31B. The average dimension in the second direction W of the portion of region 2-2 32B exposed on the fourth surface F4 is set as the average value in the second direction W of the second internal electrode 30B exposed on the same surface. The average dimension in the second direction W of region 2-1 31B is set as the average value in the second direction W of the second internal electrode 30B located at 1 / 2 position in the first direction L of the laminate 10, on the same plane parallel to the lamination direction T and the second direction W.

[0100] Furthermore, the structure of the second internal electrode 30B generally corresponds, for example, to the structure in which the first internal electrode 30A is reversed in the first direction L. The structure of the 2-1 region 31B generally corresponds, for example, to the structure in which the first-1 region 31A is reversed in the first direction L, and the structure of the 2-2 region 32B generally corresponds, for example, to the structure in which the first-2 region 32A is reversed in the first direction L. However, the structure of the second internal electrode 30B may not necessarily correspond to the structure in which the first internal electrode 30A is reversed in the first direction L.

[0101] The Sn concentration in region 2-2 32B is preferably higher than that in region 2-1 31B. Furthermore, a Sn layer is preferably disposed in region 2-2 32B. Regarding the Sn concentration in region 2-2 32B, it is defined as the average peak intensity at three points in TEM-EDX at a position halfway along the first direction L of region 2-2 32B, parallel to the lamination direction T and the second direction W. Similarly, regarding the Sn concentration in region 2-1 31B, it is defined as the average peak intensity at three points in TEM-EDX at a position halfway along the first direction L of the laminate 10, parallel to the lamination direction T and the second direction W.

[0102] It can be assumed that when the end of the second direction W of the 2-2 region 32B is orthogonal to the first internal electrode 30A, electric field concentration is likely to occur at the intersection of the end of the second direction W of the 2-2 region 32B and the first internal electrode 30A due to the overlap of internal electrodes 30 with different potentials. However, with this structure, reliability can be improved at the location where electric field concentration is likely to occur.

[0103] Furthermore, not limited to this, a Sn layer may also be disposed in region 2-1 31B. In this case, the thickness of the Sn layer disposed in region 2-2 32B is preferably thicker than the thickness of the Sn layer disposed in region 2-1 31B. If more Sn is included in the internal electrode 30 in order to increase the thickness of the Sn layer disposed in region 2-1 31B, the melting point of the internal electrode 30 will decrease. In the firing process described later, the coverage of the internal electrode 30 may decrease due to over-sintering of the internal electrode 30, and the electrostatic capacitance of the multilayer ceramic capacitor 1 may decrease excessively. By making the thickness of the Sn layer disposed in region 2-1 31B thinner than the thickness of the Sn layer disposed in region 2-2 32B, the influence caused by the Sn layer can be reduced in region 2-1 31B, which is the main region for forming electrostatic capacitance.

[0104] The coverage of region 32B in region 2-2 is preferably lower than that of region 31B in region 2-1. The coverage of region 32B in region 2-2 is preferably 80% or more. This helps to suppress interlayer delamination. Regarding the coverage, for example, in a plane parallel to the first direction L and the second direction W, in the field of view in the SEM image where the entire second internal electrode 30B is projected, it is calculated by dividing the area where the second internal electrode 30B actually exists by the area enclosed by the outline of the second internal electrode 30B.

[0105] Preferably, a Mg region is disposed at the end of the second direction W of the second-2 region 32B. Specifically, it is preferable that the Mg region extends from the second-2 region 32B in the second direction W. The Mg region can be observed by SEM or the like.

[0106] The thickness (dimension in the stacking direction T) of the Mg region disposed in the portion of the second-direction W at the end of the second-2 region 32B near the second-1 region 31B is preferably thicker than the thickness of the Mg region disposed in the portion of the second-direction W at the end of the second-2 region 32B near the fourth surface F4.

[0107] The area of ​​the Mg region disposed in the portion of the second-1 region 31B at the end of the second-2 region 32B in the second direction W is preferably larger than the area of ​​the Mg region disposed in the portion of the second-2 region 32B at the end of the second-2 region 32B in the second direction W, which is disposed near the fourth surface F4. Specifically, when the second-2 region 32B is divided into 5 equal parts in the first direction L, the Mg regions disposed on the second internal electrode 30B parallel to each cross-section are measured using SEM or the like in the cross-section passing through the end of the second-2 region 32B in the second direction W, which is located at the center of the second-2 region 32B in the first direction L, and in the cross-section passing through the end of the second-2 region 32B in the second direction W, which is located on the side near the third surface F3, following the region located closest to the fourth surface F4. The average value of each is then recorded.

[0108] The thickness of the Mg region disposed at the end in the second direction W of the 2-2 region 32B is preferably thicker than the thickness of the Mg region disposed at the end in the second direction W of the 2-1 region 31B.

[0109] The total number of Mg regions disposed at the end in the second direction W of the 2-2 region 32B is preferably greater than the total number of Mg regions disposed at the end in the second direction W of the 2-1 region 31B.

[0110] Therefore, when the end of the second direction W of the second region 32B is orthogonal to the first internal electrode 30A, the reliability can be improved in the part where electric field concentration is likely to occur.

[0111] The thickness of the Mg region located at the end of the second direction W of region 2-2 32B is set as the average value observed by SEM images of each Mg region at a position halfway along the first direction L of region 2-2 32B, parallel to the stacking direction T and the second direction W. Furthermore, the thickness of the Mg region located at the end of the second direction W of region 2-1 31B is set as the average value observed by SEM images of each Mg region at a position halfway along the first direction L of the laminate 10, parallel to the stacking direction T and the second direction W.

[0112] More specifically, if the multilayer ceramic capacitor 1 is polished in the first direction L, the end of the second region 32B in the second direction W will first be exposed in the WT cross-section. In the WT cross-section at this time, the number of Mg regions at the end of the second region 32B in the second direction W relative to the number of the second internal electrode 30B, the thickness of each Mg region in the stacking direction T, the thickness of each Mg region in the second direction W, and the area can be observed.

[0113] If further grinding is performed, in the WT cross-section exposing the 2-1 region 31B, the number of Mg regions at the end of the 2-1 region 31B in the second direction W, relative to the number of sheets of the second internal electrode 30B, the thickness of each Mg region in the stacking direction T, the thickness of each Mg region in the second direction W, and the area can be observed.

[0114] Furthermore, the thickness in the stacking direction T of the Mg regions within a certain range is set as the average of the values ​​obtained by measuring the maximum dimensions of the Mg regions in the stacking direction T for each Mg region existing within that range. Additionally, the thickness in the second direction W of the Mg regions within a certain range is set as the average of the values ​​obtained by measuring the maximum dimensions of the Mg regions in the second direction W for each Mg region existing within that range.

[0115] The total content of Mg and Mn in the region between region 32B (2-2) and face F5 (5) is preferably greater than the total content of Mg and Mn in the region between region 31B (2-1) and face F5 (5).

[0116] It can be assumed that the sintering of the dielectric layer 20 is prone to incompleteness in the region between region 32B (2-2) and surface F5 (5), and the density of the dielectric layer 20 is prone to decrease. However, according to this structure, the sintering properties of the dielectric layer 20 can be improved in the region between region 32B (2-2) and surface F5 (5), and the density of the dielectric layer 20 can be improved.

[0117] The particle size D50 of the dielectric material located within 5 μm of the end of region 32B in the second direction W is preferably smaller than the particle size D50 of the dielectric material in the central region when region 31B in the second direction W is divided into 5 equal parts. Regarding particle size D50, to ensure clear boundaries (grain boundaries) between particles, heat treatment was performed at 1000 °C, and each region was observed using SEM at 20,000x magnification. One hundred particles were randomly extracted from the obtained SEM images, the area of ​​the inner portion of the grain boundary of each particle was calculated, the equivalent circle diameter was calculated, and the particle size D50 was calculated based on these measurements.

[0118] Therefore, when the end of the second direction W of the second region 32B is approximately orthogonal to the first internal electrode 30A, the reliability can be improved in the part where electric field concentration is likely to occur.

[0119] For example, in the WT section, when the region sandwiched between the 2-2 region 32B and the 1-1 region 31A is divided into three equal parts in the second direction W, it is preferable that at least one of the following conditions is met: the particle size D50 of the dielectric particles in the central region of the three regions is larger than the particle size D50 of the dielectric particles in the region located on the 5th face F5 side of the three regions, or larger than the particle size D50 of the dielectric particles in the region located on the 6th face F6 side of the three regions.

[0120] For example, in the LT section, when the region sandwiched between the 2-2 region 32B and the 1-1 region 31A is divided into three equal parts in the first direction L, it is preferable that at least one of the following conditions is met: the particle size D50 of the dielectric particles in the central region of the three regions is larger than the particle size D50 of the dielectric particles in the region on the fourth face F4 side of the three regions; or the particle size D50 of the dielectric particles in the region on the third face F3 side of the three regions is larger than the particle size D50 of the dielectric particles in the region on the fourth face F4 side of the three regions.

[0121] Therefore, when the end of the second direction W in the second region 32B is approximately orthogonal to the first internal electrode 30A, it is possible to suppress capacitance drop in most of the capacitor formation and improve reliability in areas where electric field concentration is likely to occur.

[0122] (Invalid part)

[0123] The invalid portion 12 is the region where the internal electrode 30 is not disposed. The invalid portion 12 has an outer layer portion 13 that clamps the effective portion 11 from the stacking direction T and a lateral spacer portion 14 that clamps the effective portion 11 from the second direction W.

[0124] (Outer layer)

[0125] The outer layer 13 is disposed on the first surface F1 side and the second surface F2 side of the effective part 11. The material of the outer layer 13 may be the same as or different from the material of the dielectric layer 20 of the effective part 11. The additives added to the outer layer 13 may also be different from the additives added to the dielectric layer 20 of the effective part 11.

[0126] (Side gap)

[0127] The lateral spacers 14 are respectively disposed on the fifth surface F5 side and the sixth surface F6 side of the effective portion 11 in the laminate 10. The material of the lateral spacers 14 may be the same as or different from the material of the dielectric layer 20 of the effective portion 11. The additives added to the lateral spacers 14 may also be different from the additives added to the dielectric layer 20 of the effective portion 11.

[0128] (External electrode)

[0129] The external electrode 40 has a first external electrode 40A and a second external electrode 40B. The first external electrode 40A is disposed on the third surface F3 and extends from the third surface F3 to the first surface F1, the second surface F2, the fifth surface F5, and the sixth surface F6. The second external electrode 40B is disposed on the fourth surface F4 and extends from the fourth surface F4 to the first surface F1, the second surface F2, the fifth surface F5, and the sixth surface F6. Where there is no need to distinguish between the first external electrode 40A and the second external electrode 40B in the description, they will be uniformly referred to as "external electrode 40".

[0130] The external electrodes 40 (40A, 40B) have, for example, a base electrode 41 (41A, 41B) disposed on the outer surface of the laminate 10 and a plating layer 43 (43A, 43B) disposed on the base electrode 41 (41A, 41B).

[0131] The base electrode 41 is, for example, a sintered layer comprising a conductive metal and a glass composition. The conductive metal is, for example, Cu.

[0132] The plating layers 43 (43A, 43B) preferably include a lower plating layer 44 (44A, 44B) disposed on the base electrode 41 (41A, 41B) and an upper plating layer 45 (45A, 45B) disposed on the lower plating layer 44 (44A, 44B). In this embodiment, the lower plating layer 44 is a Ni plating layer 44, and the upper plating layer 45 is a Sn plating layer 45.

[0133] The Ni plating layer 44 prevents the base electrode 41 from being corroded by solder when mounting ceramic electronic components. The Sn plating layer 45 improves the wettability of solder when mounting the multilayer ceramic capacitor 1, thus facilitating mounting.

[0134] Furthermore, the structure of the external electrode 40 is not limited to the structure described above.

[0135] For example, the conductive metal contained in the base electrode 41 is not limited to Cu, but can also be Ni, Ag, Pd, Au, Ag-Pd alloy, etc. The base electrode 41 can also contain ceramic powder as a common material. The external electrode 40 can also have a base electrode 41 containing Ni and the common material, for example. For example, in an external electrode 40 having a base electrode 41 containing Cu and glass, a Ni plating layer 44, and a Sn plating layer 45, a base electrode 41 containing Ni and the common material can be provided instead of a base electrode 41 containing Cu and glass, or a base electrode 41 containing Ni and the common material can be provided in addition to a base electrode 41 containing Cu and glass.

[0136] The external electrode 40 may also have a resin layer comprising conductive particles and a thermosetting resin. The resin layer is formed by applying a conductive paste comprising conductive particles and a thermosetting resin to the base electrode 41 or the laminate 10 and then subjecting it to further heat treatment.

[0137] The external electrode 40 may, for example, include a base electrode 41 comprising Cu and glass, a resin layer formed on the base electrode 41, a Ni plating layer 44 formed on the resin layer, and a Sn plating layer 45 formed on the Ni plating layer 44. Alternatively, the resin layer may be formed directly on the laminate 10, or it may replace the base electrode 41. Multiple resin layers may also exist.

[0138] The substrate electrode 41 can also be formed by a thin film formation method such as sputtering or vapor deposition, and a thin film layer of metal particles less than 1 μm is deposited.

[0139] The external electrode 40 may also be a plated electrode formed solely by a plating layer without a base electrode 41. In this case, the plating layer is formed directly on the surface of the laminate 10 and is directly electrically connected to the internal electrode 30. With this configuration of the external electrode 40, the plating layer may also be formed after a catalyst is disposed on the surface of the laminate 10 as a pretreatment for plating.

[0140] The plating layer serving as the plating electrode preferably comprises a lower plating layer 44 formed on the surface of the laminate 10 and an upper plating layer 45 formed on the surface of the lower plating layer 44. The lower plating layer 44 is preferably formed using Ni, which has solder resist properties. However, when Ni is used to form the internal electrode 30, the lower plating layer 44 is preferably formed using Cu, which has good bonding with Ni. The upper plating layer 45 is preferably formed using Sn or Au, which have good solder wettability. Furthermore, the upper plating layer 45 can be formed as needed.

[0141] The structure of the external electrode 40 is not limited to the structure described above and can be modified appropriately. The external electrode 40 may also be a combination of two or more of the above structures.

[0142] Here, as Figure 6 As shown, the end of the second internal electrode 30B on the third surface F3 side intersects the end of the first-second region 32A in the second direction W when viewed in the stacking direction T. The end of the second internal electrode 30B on the third surface F3 side intersects, for example, a portion of the first-second region 32A in the second direction W with a substantially fixed dimension in the stacking direction T.

[0143] (Structure surrounding the first internal electrode)

[0144] (Structure at the fifth side of the WT section)

[0145] like Figure 7 As shown, in a cross-section passing through the first internal electrode 30A and the second internal electrode 30B and parallel to the stacking direction T and the second direction W, the end of the second internal electrode 30B on the fifth surface F5 side is located closer to the fifth surface F5 side than the first internal electrode 30A.

[0146] Additionally, a cross-section that is parallel to the stacking direction T and the second direction W, and on one side of the first internal electrode 30A in the second direction W, is located closer to the other side in the second direction W than on one side of the second internal electrode 30B in the second direction W, is sometimes referred to as the "cross-section WT". A cross-section that is parallel to the stacking direction T and the second direction W, and on the side of the fifth surface F5 of the second internal electrode 30B, is located closer to the fifth surface F5 of the first internal electrode 30A, is sometimes referred to as the "first cross-section WT". Figure 7 This becomes the WT section of the first intersection. Figure 7 The entire stacked ceramic capacitor 1 along the stacking direction T is shown.

[0147] Furthermore, in the portion of the end of the first-second region 32A in the second direction W that overlaps with the second internal electrode 30B in the stacking direction T, the area that becomes the intersection WT section through the WT section of the first-second region 32A can also be a part of the portion of the end of the first-second region 32A in the second direction W that overlaps with the second internal electrode 30B in the stacking direction T. The same applies to the second-second region 32B.

[0148] In the cross section WT of the intersection, the total content of Ca and Sr in the region within 5 μm of the end of the first internal electrode 30A in the second direction W is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode 30A in the second direction W. At this time, Ca and Sr may also exist as BCT particles, BST particles, and BCST particles dissolved in BT particles.

[0149] For example, in the first cross section WT, the total content of Ca and Sr in region R15, which is within 5 μm of the end of the fifth surface F5 side of the first internal electrode 30A, is greater than the total content of Ca and Sr in region R1C2, which is within 5 μm of the center of the second direction W of the first internal electrode 30A. The total content of Ca and Sr is set as the concentration of Ca and Sr present in each region during elemental analysis using TEM.

[0150] In the first cross section WT, the region in the area sandwiched by the adjacent second internal electrode 30B that is closer to the fifth surface F5 than the first internal electrode 30A sandwiched by the adjacent second internal electrode 30B is designated as "A region R1A5".

[0151] The Ca content in region R1A5a on the sixth face F6 side when region A R1A5 is bisected in the second direction W can be greater than the Ca content in region R1A5b on the fifth face F5 side when region A R1A5 is bisected in the second direction W.

[0152] (Structure at the 6th side of the WT section)

[0153] In the first cross section WT, the end of the second internal electrode 30B on the sixth surface F6 side can also be located closer to the sixth surface F6 side than the first internal electrode 30A.

[0154] In the first cross section WT, the total content of Ca and Sr in region R16, which is within 5 μm of the end of the sixth surface F6 of the first internal electrode 30A, is greater than the total content of Ca and Sr in region R1C2, which is within 5 μm of the center of the second direction W of the first internal electrode 30A.

[0155] In the first cross section WT, the region sandwiched by the adjacent second internal electrode 30B that is closer to the sixth surface F6 than the first internal electrode 30A sandwiched by the adjacent second internal electrode 30B is designated as "region A R1A6". The Ca content in region R1A6a on the fifth surface F5 side when region A R1A6 is bisected in the second direction W can also be greater than the Ca content in region R1A6b on the sixth surface F6 side when region A R1A6 is bisected in the second direction W.

[0156] (Structure in LT section)

[0157] like Figure 8 As shown, in a cross-section passing through the first internal electrode 30A and the second internal electrode 30B and parallel to the stacking direction T and the first direction L, the end of the second internal electrode 30B on the third surface F3 side is located closer to the third surface F3 side than the first internal electrode 30A.

[0158] In addition, the section that is parallel to the stacking direction T and the first direction L and whose end of the second internal electrode 30B is located on the third surface F3 side is sometimes referred to as the "intersection LT section". Figure 8 This becomes the LT section of the intersection. Figure 8 The image shows the entire stacked ceramic capacitor 1 along the stacking direction T.

[0159] Furthermore, in the portion of the end of the first-second region 32A in the second direction W that overlaps with the second internal electrode 30B in the stacking direction T, the area that becomes the intersection section LT through the LT section of the first-second region 32A can also be a part of the portion of the end of the first-second region 32A in the second direction W that overlaps with the second internal electrode 30B in the stacking direction T. The same applies to the second-second region 32B.

[0160] In the LT section of the intersection, the total content of Ca and Sr in region R13, which is within 5 μm of the end of the third surface F3 side of the first internal electrode 30A, is greater than the total content of Ca and Sr in region R1C1, which is within 5 μm of the center of the first internal electrode 30A.

[0161] In the LT section of the intersection, the region in the area sandwiched by the adjacent second internal electrode 30B that is closer to the third surface F3 than the first internal electrode 30A sandwiched by the adjacent second internal electrode 30B is designated as "region B R1B".

[0162] The combined content of Ca and Sr in region B, R1B, is greater than the combined content of Ca and Sr in region R1C1, which is within 5 μm of the center of the first internal electrode 30A.

[0163] When region B R1B is bisected along the first direction L, the total content of Ca and Sr in the inner region R1Ba along the first direction L can be greater than the total content of Ca and Sr in the outer region R1Bb along the first direction L when region B R1B is bisected along the first direction L.

[0164] (Structure around the second internal electrode)

[0165] (Structure at the fifth side of the WT section)

[0166] like Figure 9 As shown, in a cross-section passing through the first internal electrode 30A and the second internal electrode 30B and parallel to the stacking direction T and the second direction W, the end of the first internal electrode 30A on the fifth surface F5 side is located closer to the fifth surface F5 side than the end of the second internal electrode 30B on the fifth surface F5 side.

[0167] In addition, the section that is parallel to the stacking direction T and the second direction W and where the end of the first internal electrode 30A on the fifth surface F5 side is located closer to the fifth surface F5 side than the second internal electrode 30B is sometimes referred to as the "second intersection WT section". Figure 9 This becomes the WT section of the second intersection. Figure 9 The entire stacked ceramic capacitor 1 along the stacking direction T is shown.

[0168] In the second cross section WT, the total content of Ca and Sr in region R25, which is within 5 μm of the end of the fifth surface F5 side of the second internal electrode 30B, is greater than the total content of Ca and Sr in region R2C, which is within 5 μm of the center of the second direction W of the second internal electrode 30B.

[0169] In the second cross section WT, the region in the area sandwiched by the adjacent first internal electrode 30A that is closer to the fifth surface F5 than the second internal electrode 30B sandwiched by the adjacent first internal electrode 30A is designated as "A region R2A5".

[0170] When region A R2A5 is bisected along the second direction W, the Ca content in the inner region R2A5a along the second direction W can be greater than the Ca content in the outer region R2A5b along the second direction W when region A R2A5 is bisected along the second direction W.

[0171] (Structure at the 6th side of the WT section)

[0172] In the second cross section WT, the end of the first internal electrode 30A on the sixth surface F6 side may also be located closer to the sixth surface F6 side than the end of the second internal electrode 30B on the sixth surface F6 side.

[0173] In the second cross section WT, the total content of Ca and Sr in region R26, which is within 5 μm of the end of the sixth surface F6 side of the second internal electrode 30B, is greater than the total content of Ca and Sr in region R2C, which is within 5 μm of the center of the second direction W of the second internal electrode 30B.

[0174] In the second intersection WT section, the region sandwiched by the adjacent first internal electrode 30A that is closer to the sixth surface F6 than the second internal electrode 30B sandwiched by the adjacent first internal electrode 30A is designated as "region A R2A6". When region A R2A6 is bisected in the second direction W, the Ca content in the inner region R2A6a in the second direction W can also be greater than the Ca content in the outer region R2A6b in the second direction W when region A R2A6 is bisected in the second direction W.

[0175] (Structure in LT section)

[0176] like Figure 8 As shown, in a cross section (cross section LT) in which the end of the second internal electrode 30B on the third surface F3 side is located closer to the third surface F3 side than the end of the first internal electrode 30A on the third surface F3 side, the end of the first internal electrode 30A on the third surface F3 side is located closer to the fourth surface F4 side than the end of the second internal electrode 30B on the third surface F3 side.

[0177] In the LT section of the intersection, the total content of Ca and Sr in region R13, which is within 5 μm of the end of the third surface F3 side of the first internal electrode 30A, is greater than the total content of Ca and Sr in region R1C1, which is within 5 μm of the center of the first internal electrode 30A.

[0178] In the LT section of the intersection, the region in the area sandwiched by the adjacent first internal electrode 30A that is closer to the fourth surface F4 than the second internal electrode 30B sandwiched by the adjacent first internal electrode 30A is designated as "region B R2B".

[0179] The combined Ca and Sr content in region R2B is greater than the combined Ca and Sr content in region R2C1, which is within 5 μm of the center of the second internal electrode 30B.

[0180] When region B is bisected along the first direction L, the total content of Ca and Sr in the outer region R2Bb along the first direction L can be greater than the total content of Ca and Sr in the inner region R2Ba along the first direction L when region B is bisected along the first direction L.

[0181] (Manufacturing method of multilayer ceramic capacitor 1)

[0182] Next, the manufacturing method of the multilayer ceramic capacitor 1 according to the embodiment will be described.

[0183] (Dielectric wafer preparation process)

[0184] Prepare a ceramic slurry containing ceramic raw materials, binders, solvents, etc., where the ceramic raw materials include dielectric ceramic materials. Additives such as rare earth elements and sintering aids are added to the ceramic slurry. Next, the ceramic slurry is molded into sheets to become dielectric sheets. Dielectric sheets for the inner layer and outer layer are prepared as dielectric sheets. The composition of the inner layer and outer layer dielectric sheets can also be different.

[0185] (Internal electrode pattern formation process)

[0186] The pattern of the internal electrode 30 (sometimes simply referred to as the "internal electrode pattern") is printed on the dielectric sheet using conductive paste. Regarding the internal electrode pattern, the portion that becomes region 1-1 31A and the portion that becomes region 1-2 32A are printed, respectively, so that they are in the desired shapes. The internal electrode pattern is formed, for example, by screen printing, gravure printing, letterpress printing, etc.

[0187] (Preparation process for step-absorbing paste)

[0188] A step-absorbing paste is disposed on a dielectric sheet. The step-absorbing paste is disposed on the region of the dielectric sheet that is aligned with the first-2 region 32A in the first direction L. Additionally, the step-absorbing paste is also disposed, for example, on the region of the dielectric sheet that is aligned with the second-2 region 32B in the first direction L. Hereinafter, as an example, the case where the step-absorbing paste is disposed around the periphery of the first internal electrode 30A will be described. Furthermore, in Figure 4 In the diagram, the region on the dielectric sheet that is aligned with the first-second region 32A in the first direction L is shown as "region R31". Figure 5 In the diagram, the region on the dielectric sheet that is aligned with region 32B in the first direction L is shown as “region R32”.

[0189] By making the concentration of a specific element in the step absorbent paste higher than the concentration of that element in the dielectric sheet used in the inner layer, the element concentration can be locally adjusted in the laminate 10. Furthermore, the element in the step absorbent paste diffuses into the inner electrode pattern and the dielectric sheet. Therefore, the element concentration in the portion of the inner electrode pattern close to the step absorbent paste can be made higher than the element concentration in the portion of the inner electrode pattern far from the step absorbent paste.

[0190] For example, by making the Ca concentration in the step absorbent paste higher than the Ca concentration in the dielectric sheet used in the inner layer, the Ca concentration in the portion of the internal electrode pattern close to the step absorbent paste (e.g., the end on the third surface F3 side of the first internal electrode 30A in the cross section LT) can be higher than the Ca concentration in the portion of the internal electrode pattern far from the step absorbent paste (e.g., the central portion in the first direction L of the first internal electrode 30A in the cross section LT). The same applies in the case of Sr. Furthermore, not limited to this, the concentration can be increased by changing the proportions of BCT particles, BST particles, BSCT particles, and BT particles in which Ca and Sr are pre-dissolved in BT particles.

[0191] Regarding the step-absorbing paste, although it still depends on the width in the second direction W of the internal electrode, it is preferably configured to be at least -30 μm and less than 100 μm away from the edge of the internal electrode pattern. "-" indicates separation from the internal electrode, and "+" indicates overlap with the internal electrode. In this case, when the shape of the internal electrode pattern becomes a racket shape, a step-absorbing paste with a partially increased proportion of BCT particles, BST particles, and BSCT particles is applied to the tilted area, and then a rectangular printing mask and printing plate are used to overlap the step-absorbing paste. Furthermore, not limited to this, the step-absorbing paste can also be configured to contain a greater amount of CaCO3 in addition to BCT particles, BST particles, and BSCT particles, and then a rectangular printing mask and printing plate can be used to overlap the step-absorbing paste.

[0192] Alternatively, the step-absorbing paste may contain an ingredient that readily repels the internal electrode paste as a binder. In this case, excessive overlap between the internal electrode paste and the step-absorbing paste can be suppressed. Consequently, internal defects that may occur during pressing due to a partial increase in the thickness of the laminate can be prevented.

[0193] Alternatively, a hydrophobic film can be formed in the portion of the internal electrode pattern that becomes region 32A (1-2) after the internal electrode paste has been printed. In this case, when the step-absorbing paste climbs onto the internal electrode pattern, it can flow to the outside of the internal electrode pattern. At this time, F (fluorine), Si, etc., can be included in region 32A, or F and Si can be included in the dielectric layer near region 32A.

[0194] In the step absorbent paste, sintering aids such as Mg, Mn, Al, and V are included as other additives. The amount of sintering aids included in the step absorbent paste is preferably greater than the amount of sintering aids included in the inner dielectric layer paste. In this case, the sinterability near the area where the step absorbent paste is applied can be improved, resulting in increased density and thus suppressing the decrease in moisture resistance.

[0195] Rare earth elements can also be included in the step absorber paste. Examples of rare earth elements include Dy, Tb, Ho, and Gd. If the amount of rare earth elements in the step absorber paste is too small compared to the amount in the dielectric layer paste, the rare earth elements in the inner dielectric layer paste may diffuse excessively into the area where the step absorber paste is disposed, potentially causing abnormal particle growth at the internal electrode tip. In this case, reliability may decrease. Furthermore, if the amount of rare earth elements in the step absorber paste is too large compared to the amount in the dielectric layer paste, the sinterability and density near the area where the step absorber paste is disposed may decrease. Therefore, for example, the amount of Dy in the step absorber paste is preferably set to 110% or more and 400% or less relative to the amount of Dy in the ceramic slurry that forms the dielectric layer.

[0196] Furthermore, it is preferable to include Si in the step absorber paste. The amount of Si contained in the step absorber paste is preferably adjusted appropriately in accordance with the desired sinterability of the dielectric layer paste, the type and amount of rare earth elements contained in the step absorber paste. By increasing the amount of Si contained in the step absorber paste, the density near the area where the step absorber paste is disposed can be improved. The amount of Si contained in the step absorber paste is preferably set to 110% or more and 200% or less relative to the amount of Si contained in the dielectric layer paste. In addition, Li and Na may also be included in the step absorber paste. In this case, the amount of Li contained in the step absorber paste can be set to be more than the amount of Li contained in the dielectric layer paste, and the amount of Na contained in the step absorber paste can be set to be more than the amount of Na contained in the dielectric layer paste.

[0197] The amount of Sn contained in the step absorption paste is preferably greater than that contained in the dielectric layer paste. The amount of Sn contained in the step absorption paste is preferably 0.1 mol% or more and 3.0 mol% or less. This allows for the easy formation of a Sn layer within the first and second regions 32A while suppressing the decrease in the melting point of the internal electrode.

[0198] In addition, there is no particular restriction on the order of performing the internal electrode patterning process and the step absorption paste preparation process.

[0199] (Layering process)

[0200] The inner layer dielectric sheets are stacked. The inner layer dielectric sheets are stacked such that the internal electrode patterns are staggered by half a pitch between adjacent sheets in the first direction L. Next, outer layer dielectric sheets are stacked on both sides of the stacked inner layer dielectric sheets in the stacking direction T. The outer layer dielectric sheets are thermo-pressed onto the dielectric sheets. Thus, a master block is obtained. In addition, each outer layer 13 can be composed of multiple dielectric sheets or a single dielectric sheet.

[0201] (Pressing process)

[0202] The parent block is pressed along the stacking direction T by means of isostatic pressing and other methods.

[0203] At this point, if the internal electrode pattern becomes the same as the internal electrode pattern of a racket structure, then a portion without an internal electrode pattern may easily form near the region 32A (region 1-2) within the internal electrode pattern. When the master block is pressed, this portion without an internal electrode pattern may experience significant deformation.

[0204] However, by applying a step-absorbing paste to the portion near the first-second region 32A where no internal electrode exists, the step caused by the presence or absence of the first internal electrode 30A is reduced. Thus, the generation of localized deformation is suppressed in the master block with the internal electrode pattern of the racket structure.

[0205] Furthermore, the composition of the step-absorbing paste can be independently adjusted from the composition of the dielectric sheet used in the inner layer. Therefore, the composition of the dielectric layer 20 disposed near the first-second region 32A can be different from the composition of the dielectric layer 20 disposed at other locations. Furthermore, since elements in the dielectric layer 20 move into the first-second region 32A, the elements contained in the first-second region 32A can be different from the elements contained in the first-first region 31A. In addition, the composition of the dielectric material present near the first-second region 32A can be different.

[0206] (Main block cutting process)

[0207] The parent block is divided along a cutting line corresponding to the dimensions of the laminate. For example, the parent block is cut using a cutting device with a cutting blade. For example, the parent block is cut along a first direction L in the lamination direction T, and also along a second direction W in the lamination direction T. This yields multiple cuboid blocks (called "laminated pieces"). Furthermore, for example, it is preferable to round the corners and edges of the laminated pieces by tumbling.

[0208] (Side spacer formation process)

[0209] Prepare the ceramic slurry for the side spacers. The composition of the ceramic slurry for the side spacers can be the same as or different from that of the ceramic slurry for the inner layer. Additives that are different from those added to the ceramic slurry for the inner layer can also be added to the ceramic slurry for the side spacers. For example, the ceramic slurry for the side spacers may contain Ca.

[0210] A ceramic slurry for side spacers is applied to a resin film and allowed to dry. This creates a dielectric sheet for the side spacers. The dielectric sheet for the side spacers is then adhered to the surface of the laminated sheet that exposes the internal electrode 30. This forms a layer of side spacers 14 on the laminated sheet. Each side spacer 14 can be composed of multiple dielectric sheets or a single dielectric sheet. The side spacer formation process is not necessarily required; for example, it can be reduced by arranging the internal electrode pattern with open intervals in the second direction W. Even in this case, the step absorption paste is applied to the portion near the first-second region 32A where no internal electrode exists.

[0211] (Laminated body firing process)

[0212] The laminated sheets are heated in a nitrogen atmosphere for a given time at a given firing temperature. This yields laminate 10.

[0213] (Substrate electrode formation process)

[0214] Base electrodes 41 are formed on the third surface F3 and the fourth surface F4, respectively. A conductive paste containing glass and metal components is prepared as the conductive paste serving as the base electrodes 41. The conductive paste serving as the base electrodes 41 is applied to the third surface F3 and the fourth surface F4, respectively. For example, the conductive paste applied to the third surface F3 is applied to cover the entire third surface F3, a portion of the first surface F1, a portion of the second surface F2, a portion of the fifth surface F5, and a portion of the sixth surface F6. Similarly, the conductive paste applied to the fourth surface F4 is applied to cover the entire fourth surface F4, a portion of the first surface F1, a portion of the second surface F2, a portion of the fifth surface F5, and a portion of the sixth surface F6.

[0215] (Substrate electrode sintering process)

[0216] The laminate 10, to which the base electrode 41 is formed, is heated in a nitrogen atmosphere at a given firing temperature for a given time. Thus, the base electrode 41 is fired onto the laminate 10. Alternatively, the laminate firing process can be performed simultaneously with the base electrode firing process.

[0217] (Platinum coating process)

[0218] A plating layer 43 is formed on the base electrode 41. A lower plating layer 44 is formed on the base electrode 41. Next, an upper plating layer 45 is formed on the lower plating layer 44. The lower plating layer 44 is formed, for example, by plating Ni. The upper plating layer 45 is formed, for example, by plating Sn. The lower plating layer 44 and the upper plating layer 45 are formed sequentially, for example, by electrolytic plating. Thus, the external electrode 40 is formed.

[0219] Based on the above, we can obtain Figure 1 The stacked ceramic capacitor 1 shown.

[0220] <Effects of the Implementation Method>

[0221] The multilayer ceramic capacitor 1 according to the above embodiment can achieve the following effects.

[0222] According to the above embodiment, the laminate 10 has a first internal electrode 30A with one end exposed on the third surface F3, a second internal electrode 30B with one end exposed on the fourth surface F4, and a dielectric layer 20 containing at least one of Ca and Sr. In a cross-section located in the second direction W parallel to the lamination direction T and the second direction W, and at the end of the second internal electrode 30B on the fifth surface F5 side, the total content of Ca and Sr in the region R15 within a distance of 5 μm from the end of the first internal electrode 30A on the second direction W on the fifth surface F5 side is greater than the total content of Ca and Sr in the region R1C2 within a distance of 5 μm from the center of the first internal electrode 30A on the second direction W.

[0223] If the shape of the first internal electrode 30A is set to the shape of a racket, then the WT cross section at a certain position in the first direction L of the multilayer ceramic capacitor 1 becomes the first intersection WT cross section. In this case, the end of the first internal electrode 30A (first-second region 32A) and the end of the second internal electrode 30B intersect, and it can be considered that electric field concentration is likely to occur at this intersection. However, according to this structure, the end of the first internal electrode 30A in the second direction W in the intersection WT cross section becomes the part of the end of the first internal electrode 30A that intersects with the end of the second internal electrode 30B. By increasing the total content of Ca and Sr in the region within 5 μm of the end of the first internal electrode 30A in the second direction W, it is possible to suppress the degradation of insulation caused by the movement of oxygen holes in the part where reliability is prone to decline.

[0224] Therefore, it is possible to provide multilayer ceramic capacitors with excellent reliability.

[0225] Furthermore, by forming the first internal electrode 30A in the shape of a racket, the path for moisture from the outside of the laminate 10 to reach the first internal electrode 30A can be extended. This improves the moisture resistance reliability of the laminated ceramic capacitor 1.

[0226] According to the above embodiment, in the first intersection WT section, when the region sandwiched by the adjacent second internal electrode 30B is designated as region A (e.g., region A R1A5), the region on the other side of the second direction W (e.g., the sixth surface F6 side) of region A R1A5 when region A R1A5 is bisected in the second direction W has a higher Ca content than the region on the other side of the second direction W when region A R1A5 is bisected in the second direction W (e.g., the fifth surface F5 side).

[0227] By increasing the content of dielectric particles that become BCT, BST, and BSCT near the second direction W in region 1-2 32A, it is possible to suppress the degradation of insulation caused by the movement of oxygen holes.

[0228] According to the above embodiment, in a cross-section where the end of the second internal electrode 30B on the third surface F3 side is located closer to the third surface F3 side than the end of the first internal electrode 30A on the third surface F3 side, which is parallel to the stacking direction T and the first direction L, the total content of Ca and Sr in the region within 5 μm of the end of the first internal electrode 30A on the third surface F3 side is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode 30A.

[0229] If the shape of the first internal electrode 30A is set to the shape of a racket, then the LT cross section at a certain position in the second direction W of the multilayer ceramic capacitor 1 becomes the intersection LT cross section. In this case, the end of the first internal electrode 30A (first-second region 32A) and the end of the second internal electrode 30B intersect, and it can be considered that electric field concentration is likely to occur at this intersection. However, according to this structure, by increasing the total content of Ca and Sr in the region within 5 μm of the end of the first internal electrode 30A on one side in the first direction L, it is possible to suppress the degradation of insulation caused by the movement of oxygen holes near the intersection of the end of the first internal electrode 30A and the end of the second internal electrode 30B.

[0230] Therefore, it is possible to provide multilayer ceramic capacitors with excellent reliability.

[0231] According to the above embodiment, when the region sandwiched by the adjacent second internal electrode 30B, and the region closer to the third surface F3 than the first internal electrode 30A sandwiched by the adjacent second internal electrode 30B is designated as region B R1B, the total content of Ca and Sr in region B R1B is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode 30A.

[0232] Generally speaking, compared with BaTiO3, Ba 1-x Ca x TiO3, Ba 1-x Sr x TiO3 has a low lattice constant, making it easy to trap oxygen vacancies. Furthermore, because of its low lattice constant, its dielectric constant tends to be low. Therefore, by adopting the above structure, the dielectric constant of most of the components forming the electrostatic capacitance is relatively high. By locally increasing Ca and Sr in the areas where reliability is prone to decline, reliability can be improved while maintaining a high overall electrostatic capacitance.

[0233] According to the above implementation, when region B R1B is bisected in the first direction L, the total content of Ca and Sr in the inner region R1Ba in the first direction L can also be greater than the total content of Ca and Sr in the outer region R1Bb in the first direction L when region B R1B is bisected in the first direction L.

[0234] By increasing the content of dielectric particles that become BCT, BST, and BSCT near the second direction W in region 1-2 32A, it is possible to suppress the degradation of insulation caused by the movement of oxygen holes.

[0235] Furthermore, the same effect can be obtained by using a structure corresponding to the structure that achieves the above-mentioned effect, and a structure corresponding to the structure that achieves the above-mentioned effect and relating to the second internal electrode 30B.

[0236] This invention is not limited to the structures described in the above embodiments, and can be applied by appropriate modifications without changing the spirit of the invention. Furthermore, combining two or more structures for each preferred structure described in the above embodiments also constitutes the present invention.

[0237] For example, in the above embodiment, when viewed in the stacking direction T, the end of the fourth surface F4 side of the first internal electrode 30A intersects the portion of the second direction W dimension fixed in the second-2 region 32B, and the end of the third surface F3 side of the second internal electrode 30B intersects the portion of the first-2 region 32A with a fixed second direction W dimension, but it is not limited to these. Figure 10 As shown, when viewed in the stacking direction T, the end of the first internal electrode 30A on the fourth surface F4 side may also intersect with the portion of the second direction W in the second-2 region 32B where the dimension gradually decreases from the third surface F3 side toward the fourth surface F4 side, and the end of the second internal electrode 30B on the third surface F3 side may also intersect with the portion of the second direction W in the first-2 region 32A where the dimension gradually decreases from the fourth surface F4 side toward the third surface F3 side.

Claims

1. A multilayer ceramic capacitor, comprising: The laminate has a first and a second surface opposite to each other in the lamination direction, a third and a fourth surface opposite to each other in the first direction orthogonal to the lamination direction, and a fifth and a sixth surface opposite to each other in the second direction orthogonal to the lamination direction and the first direction; A first external electrode is disposed on the third surface; and The second external electrode is disposed on the fourth surface. The laminate has: a first internal electrode, one end of which is exposed on the third surface; a second internal electrode, one end of which is exposed on the fourth surface; and a dielectric layer comprising at least one element selected from Ca and Sr. In a cross-section parallel to both the stacking direction and the second direction, and in which the end of the second internal electrode in the second direction is located closer to the fifth surface than the first internal electrode, The total content of Ca and Sr in the region within 5 μm of the end of the fifth surface of the first internal electrode is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode in the second direction.

2. The multilayer ceramic capacitor according to claim 1, wherein, When region A is defined as the area within the region sandwiched by the adjacent second internal electrode that is closer to the fifth surface than the first internal electrode sandwiched by the adjacent second internal electrode, When region A is divided into two equal parts in the second direction, the Ca content in the inner region in the second direction is greater than the Ca content in the outer region in the second direction.

3. A multilayer ceramic capacitor, comprising: The laminate has a first and a second surface opposite to each other in the lamination direction, a third and a fourth surface opposite to each other in the first direction orthogonal to the lamination direction, and a fifth and a sixth surface opposite to each other in the second direction orthogonal to the lamination direction and the first direction; A first external electrode is disposed on the third surface; and The second external electrode is disposed on the fourth surface. The laminate has: a first internal electrode, one end of which is exposed on the third surface; a second internal electrode, one end of which is exposed on the fourth surface; and a dielectric layer comprising at least one element selected from Ca and Sr. In a cross-section where the end of the second internal electrode is located on the third surface side, which is parallel to the stacking direction and the first direction and is closer to the third surface side than the end of the first internal electrode on the third surface side, The total content of Ca and Sr in the region within 5 μm of the end of the third surface of the first internal electrode is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode in the first direction.

4. The multilayer ceramic capacitor according to claim 3, wherein, When region B is defined as the area within the region sandwiched by the adjacent second internal electrode that is closer to the third surface than the first internal electrode sandwiched by the adjacent second internal electrode, The total content of Ca and Sr in region B is greater than the total content of Ca and Sr in the region within 5 μm of the center of the first internal electrode.

5. The multilayer ceramic capacitor according to claim 4, wherein, When region B is divided into two equal parts in the first direction, the total content of Ca and Sr in the outer region in the first direction is greater than the total content of Ca and Sr in the inner region in the first direction when region B is divided into two equal parts in the first direction.

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