Multilayer ceramic capacitor

Abstract

To provide a multilayer ceramic capacitor with high capacity and excellent reliability.SOLUTION: In a multilayer ceramic capacitor 1, a multilayer body 2 includes internal electrodes 15, and a plurality of dummy electrodes, which do not contribute to the formation of electrostatic capacitance, that are disposed on a first main surface AA side relative to the internal electrode 15 that is disposed closest to the first main surface AA side. The dummy electrodes 5 include an external dummy electrode 5A, which is disposed closest to the first main surface AA side among the plurality of dummy electrodes, and an inner dummy electrode 5B that is disposed on the internal electrode 15 side relative to the external dummy electrode 5A. The coverage of the external dummy electrode 5A is lower than that of the internal electrode 15.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a multilayer ceramic capacitor.

Background Art

[0002] Conventionally, in multilayer ceramic capacitors, miniaturization and high capacitance have been demanded. For this reason, attempts have been made to make the dielectric layer and the internal electrode layer thinner and multilayered. In multilayer ceramic capacitors, improvement in reliability has also been demanded.

[0003] Therefore, in order to improve the mechanical strength and moisture resistance reliability of the laminate, a technique of arranging dummy electrodes in the upper and lower cover portions of the laminate is known. A plurality of dummy electrodes may be arranged side by side. In that case, the mechanical strength etc. of the laminate can be further improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the number of dummy electrodes is increased, the dummy electrodes and the outer surface of the laminate approach each other. In the vicinity of the outer surface of the laminate, it is considered that a load is likely to act on the dummy electrodes. For this reason, there is a risk that problems such as delamination are likely to occur in the dummy electrodes near the outer surface.

[0006] An object of the present invention is to provide a multilayer ceramic capacitor having high capacitance and excellent reliability.

Means for Solving the Problems

[0007] In order to solve the above problems, a multilayer ceramic capacitor of the present invention includes an inner layer portion including alternately laminated dielectric layers and internal electrodes, a pair of outer layer portions provided with the inner layer portion interposed therebetween in the lamination direction, a first main surface and a second main surface facing each other in the lamination direction, a first side surface and a second side surface facing each other in a width direction orthogonal to the lamination direction, and a first end surface and a second end surface facing each other in a length direction orthogonal to the lamination direction and the width direction, a laminate having the same, and external electrodes arranged in pairs on at least one of the side surfaces and the end surfaces, the multilayer ceramic capacitor being provided, in the lamination direction, a direction in which the central portion of the laminate in the lamination direction is viewed from each main surface is defined as the outside in the lamination direction, and a direction in which the central portion of the laminate in the lamination direction is viewed from each main surface is defined as the inside in the lamination direction, the laminate has a plurality of dummy electrodes that are electrodes that do not contribute to the formation of capacitance and are arranged outside the internal electrodes in the lamination direction, the plurality of dummy electrodes include an outer dummy electrode arranged most outside in the lamination direction among the plurality of dummy electrodes and an inner dummy electrode arranged inside the outer dummy electrode in the lamination direction, and the coverage of the outer dummy electrode is lower than the coverage of the internal electrode.

Effect of the Invention

[0008] According to the present invention, a multilayer ceramic capacitor having a high capacitance and excellent reliability can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, a multilayer ceramic capacitor 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0011] (Multilayer Ceramic Capacitor 1) As shown in FIG. 1, the multilayer ceramic capacitor 1 is a so-called two-terminal structure multilayer ceramic capacitor. The multilayer ceramic capacitor 1 includes a laminate 2 and a pair of external electrodes 3. The laminate 2 has a substantially rectangular parallelepiped shape and has six outer surfaces. The laminate 2 includes an inner layer portion 11 in which a dielectric layer 14 and an internal electrode 15 are laminated.

[0012] In this specification, in the multilayer ceramic capacitor 1, the direction in which the dielectric layer 14 and the internal electrode 15 are laminated is defined as the lamination direction T. One of the directions orthogonal to the lamination direction T is defined as the length direction L. The direction orthogonal to both the length direction L and the lamination direction T is defined as the width direction W. Among the lamination direction T, the direction from the central portion of the lamination direction T of the laminate 2 toward each main surface A is defined as the "outside in the lamination direction", and among the lamination direction T, the direction from each main surface A toward the central portion of the lamination direction T of the laminate 2 is defined as the "inside in the lamination direction".

[0013] Among the six outer surfaces of the laminate 2, a pair of outer surfaces provided on both sides in the lamination direction T are defined as the first main surface AA and the second main surface AB, a pair of outer surfaces provided on both sides in the width direction W and extending in the lamination direction T are defined as the first side surface BA and the second side surface BB, and a pair of outer surfaces provided on both sides in the length direction L and extending in the lamination direction T are defined as the first end surface CA and the second end surface CB. The first main surface AA and the second main surface AB may be collectively referred to as "each main surface A". The first side surface BA and the second side surface BB may be collectively referred to as "each side surface B". The first end surface CA and the second end surface CB may be collectively referred to as "each end surface C".

[0014] Note that the pair of external electrodes 3 are respectively provided on each end surface C. Each external electrode 3 is arranged in the length direction L.

[0015] A cross-section of the multilayer ceramic capacitor 1 parallel to the lamination direction T and the length direction L is defined as the "LT cross-section". Note that the cross-sections of FIGS. 2 and 3 are LT cross-sections passing through the central portion in the width direction W of the multilayer ceramic capacitor 1.

[0016] (Multilayer body 2) The multilayer body 2 has an inner layer portion 11 and a pair of outer layer portions 12 disposed sandwiching the inner layer portion 11 in the stacking direction T. The multilayer body 2 preferably has rounded corners and ridgeline portions. Here, the corner portion is a portion where three sides of the multilayer body intersect. The ridgeline portion is a portion where two sides of the multilayer body intersect.

[0017] (Inner layer portion 11) As shown in FIGS. 2 and 3, the inner layer portion 11 has a plurality of dielectric layers 14 and a plurality of internal electrodes 15. The dielectric layers 14 and the internal electrodes 15 are alternately stacked.

[0018] The dielectric layer 14 is formed of, for example, a dielectric ceramic mainly composed of BaTiO3. The dielectric ceramic may contain an Mn compound, an Fe compound, a Cr compound, a Co compound, a Ni compound, etc. as sub-components.

[0019] The internal electrode 15 is formed of, for example, a metal material such as Ni, Cu, Ag, Pd, an Ag - Pd alloy, Au, etc. The internal electrode 15 has a plurality of first internal electrodes 15A and a plurality of second internal electrodes 15B. The first internal electrode 15A is exposed only at the first end face CA. The second internal electrode 15B is exposed only at the second end face CB. The first internal electrodes 15A and the second internal electrodes 15B are alternately arranged.

[0020] The first internal electrode 15A has a first opposing portion 16A and two first lead - out portions 17A. The first opposing portion 16A is a portion of the first internal electrode 15A that faces the second internal electrode 15B adjacent in the stacking direction T. The first opposing portion 16A is located at the central portion between the end faces C. The first lead - out portion 17A is a portion of the first internal electrode 15A drawn from the first opposing portion 16A toward the first end face CA side. The first opposing portion 16A is exposed at the first end face CA.

[0021] The second internal electrode 15B has a second opposing portion 16B and two second lead-out portions 17B. The second opposing portion 16B is the portion of the second internal electrode 15B that faces the adjacent first internal electrode 15A (first opposing portion 16A). The second opposing portion 16B is located at the central portion between the respective end faces C. The second lead-out portion 17B is the portion of the second internal electrode 15B that is led out from the second opposing portion 16B toward the second end face CB side. The second opposing portion 16B is exposed on the second end face CB.

[0022] Note that the first internal electrode 15A and the second internal electrode 15B may be collectively referred to as the "internal electrode 15". The first opposing portion 16A and the second opposing portion 16B may be collectively referred to as the "opposing portion 16". Also, in the laminate 2, the internal electrode 15 closest to the first main surface AA side is the first internal electrode 15A, and the internal electrode 15 closest to the second main surface AB side is the second internal electrode 15B.

[0023] (Outer layer portion 12) The outer layer portion 12 is formed of the same material as the dielectric layer 14 of the inner layer portion 11. Note that no internal electrode 15 is disposed in the outer layer portion 12. Also, among the pair of outer layer portions 12, the one on the first main surface AA side is referred to as the "first outer layer portion 12A", and the one on the second main surface AB side is referred to as the "second outer layer portion 12B".

[0024] (External electrode 3) Each external electrode 3 is disposed on each end face C respectively. Each external electrode 3 covers not only the end face C but also a part of the main surface A and a part of the side surface B. Among each external electrode 3, the one disposed on the first end face CA is referred to as the "first external electrode 3A", and the one disposed on the second end face CB is referred to as the "second external electrode 3B". The first internal electrode 15A is connected to the first external electrode 3A. The second internal electrode 15B is connected to the second external electrode 3B. Each external electrode 3 includes a base electrode layer 31 formed in contact with the surface of the laminate 2, a first plating layer 32 disposed on the base electrode layer 31, and a second plating layer 33 disposed on the first plating layer 32, respectively.

[0025] The base electrode layer 31 is a baked layer containing, for example, a conductive metal such as Cu (copper) and glass. The first plating layer 32 is, for example, a Ni (nickel) plating layer. The second plating layer 33 is, for example, a Sn (tin) plating layer.

[0026] (Dummy electrode 5) Here, the laminate 2 has a dummy electrode 5. The dummy electrode 5 is an electrode that does not form a capacitance and is disposed inside the laminate 2. Hereinafter, the configuration of the dummy electrode 5 will be described.

[0027] The dummy electrode 5 is formed of a metal material such as, for example, Ni, Cu, Ag, Pd, an Ag - Pd alloy, or Au. The dummy electrode 5 can be formed of the same material as the internal electrode 15.

[0028] The dummy electrode 5 is disposed outside the internal electrode 15 in the stacking direction and is located more outside in the stacking direction. In other words, the dummy electrode 5 is disposed in the outer layer portion 12. The dummy electrode 5 is disposed in, for example, the first outer layer portion 12A and the second outer layer portion 12B, respectively.

[0029] The dummy electrode 5 is connected to, for example, the same external electrode 3 as the internal electrode 15 closest to the dummy electrode 5. As a result, the dummy electrode 5 is configured not to form a capacitance. The dummy electrode 5 has a dummy facing portion 51 that faces the facing portion 16 closest to the dummy electrode 5, and a dummy lead portion 52 that is drawn out from the dummy facing portion 51 to the side of the external electrode 3 connected to the internal electrode 15 closest to the dummy electrode 5.

[0030] More specifically, the internal electrode 15 closest to the dummy electrode 5A disposed in the first outer layer portion 12A is the first internal electrode 15A. The dummy lead portion 52 of the dummy electrode 5 disposed in the first outer layer portion 12A is drawn out toward the first end face CA side. The dummy lead portion 52 disposed in the first outer layer portion 12A is connected to, for example, the first external electrode 3A. The internal electrode 15 closest to the dummy electrode 5B disposed in the second outer layer portion 12B is the second internal electrode 15B. The dummy lead portion 52 of the dummy electrode 5 disposed in the second outer layer portion 12B is drawn out toward the second end face CB side. The dummy lead portion 52 disposed in the second outer layer portion 12B is connected to, for example, the second external electrode 3B.

[0031] A plurality of dummy electrodes 5 are disposed in each outer layer portion 12, and specifically, two dummy electrodes 5 are disposed in each outer layer portion 12. In each outer layer portion 12, the plurality of dummy electrodes 5 include an outer dummy electrode 5A disposed on the outermost side in the stacking direction among the dummy electrodes 5 and an inner dummy electrode 5B disposed on the inner side in the stacking direction than the outer dummy electrode 5A.

[0032] In each outer layer portion 12, the outer dummy electrode 5A and the inner dummy electrode 5B are stacked in the stacking direction T via the dielectric layer 14 forming the first outer layer portion 12A. By stacking a plurality of dummy electrodes 5, the moisture resistance reliability and mechanical strength of the laminate 2 can be improved.

[0033] However, since a plurality of dummy electrodes 5 are stacked, in particular, the outer dummy electrode 5A is close to the main surface A. For this reason, it is considered that an external load is likely to act on the outer dummy electrode 5A. Then, there is a concern that problems such as delamination are likely to occur in the outer dummy electrode 5A.

[0034] Therefore, the coverage of the outer dummy electrode 5A is lower than the coverage of the internal electrode 15.

[0035] According to such a configuration, by reducing the coverage of the outer dummy electrode 5A, the adhesion between the outer dummy electrode 5A and the dielectric layer 14 can be improved, so that delamination in the outer dummy electrode 5A can be suppressed. Thereby, the reliability of the multilayer ceramic capacitor 1 can be improved. Also, by increasing the coverage of the internal electrode 15, the capacitance can be improved.

[0036] Therefore, it is possible to provide a multilayer ceramic capacitor with high capacitance and excellent reliability.

[0037] The coverage of the outer dummy electrode 5A is preferably 40% or more and less than 60%, and the coverage of the internal electrode 15 is preferably 60% or more and 90% or less. In that case, the desired effect can be suitably obtained.

[0038] The coverage of the outer dummy electrode 5A is lower than the coverage of the inner dummy electrode 5B.

[0039] It is considered that the risk of delamination increases as the distance from the main surface A becomes closer. However, according to such a configuration, by reducing the coverage of the outer dummy electrode 5A, delamination in the outer dummy electrode 5A can be suitably suppressed. Also, by increasing the coverage of the inner dummy electrode 5B, for example, the intrusion of moisture through the voids formed in the inner dummy electrode 5B can be suppressed, so that the arrival of moisture at the internal electrode 15 can be more reliably suppressed. Thereby, the reliability of the multilayer ceramic capacitor 1 can be more suitably improved.

[0040] The coverage of the outer dummy electrode 5A is preferably 40% or more and less than 60%, and the coverage of the inner dummy electrode 5B is preferably 60% or more and 90% or less. In that case, the desired effect can be suitably obtained.

[0041] The coverage of the inner dummy electrode 5B is lower than the coverage of the internal electrode 15.

[0042] According to such a configuration, by reducing the coverage of the inner dummy electrode 5B, the adhesion between the inner dummy electrode 5B and the dielectric layer 14 can be improved, so that delamination in the inner dummy electrode 5B can be more preferably suppressed. By increasing the coverage of the internal electrode 15, a desired effect can be obtained without causing a decrease in capacitance.

[0043] The coverage of the outer dummy electrode 5A is preferably 40% or more and less than 70%, the coverage of the inner dummy electrode 5B is preferably 60% or more and less than 90%, and the coverage of the internal electrode 15 is preferably 80% or more. The coverage of the inner dummy electrode 5B is preferably higher than the coverage of the outer dummy electrode 5A, and the coverage of the internal electrode 15 is preferably higher than the inner dummy electrode 5B. In those cases, a desired effect can be preferably obtained.

[0044] The coverage of the dummy lead-out portion 52 is lower than the coverage of the lead-out portion 17.

[0045] In the laminate 2, delamination is particularly likely to occur in the dummy lead-out portion 52. Therefore, by reducing the coverage of the dummy lead-out portion 52, the occurrence of delamination in the dummy lead-out portion 52 can be effectively suppressed. By increasing the coverage of the lead-out portion 17, it becomes easier to increase the coverage of the entire internal electrode 15, so that the capacitance can be improved.

[0046] In the internal electrode 15, the coverage of the lead-out portion 17 is lower than the coverage of the opposing portion 16.

[0047] In the internal electrode 15, delamination is likely to occur in the lead-out portion 17. By reducing the coverage of the lead-out portion 17, the occurrence of delamination in the internal electrode 15 can be suppressed. Also, by increasing the coverage of the opposing portion 16, the capacitance can be improved.

[0048] As shown in FIG. 3, each dummy lead-out portion 52 (dummy lead-out portion 52A, dummy lead-out portion 52B) is drawn out from a dummy facing portion 51 (dummy facing portion 51A, dummy facing portion 51B), and has a first dummy inclined portion 54 (first dummy inclined portion 54A, first dummy inclined portion 54B) that inclines inward in the stacking direction as it goes from the dummy facing portion 51 side toward the side away from the dummy facing portion 51, and a second dummy inclined portion 55 (second dummy inclined portion 55A, second dummy inclined portion 55B) that extends from the first dummy inclined portion 54 toward the side away from the dummy facing portion 51, has a gentler inclination than the first dummy inclined portion 54, and inclines inward in the stacking direction as it goes from the dummy facing portion 51 side toward the side away from the dummy facing portion 51. Note that an A is appended to the end of the reference numeral of each part of the outer dummy electrode 5A, and a B is appended to the end of the reference numeral of each part of the inner dummy electrode 5B.

[0049] The coverage of the first dummy inclined portion 54 is lower than the coverage of the second dummy inclined portion 55.

[0050] The dummy lead-out portion 52 may be greatly inclined in the vicinity of the dummy facing portion 51. It is considered that delamination between layers is likely to occur in the inclined portion (first dummy inclined portion 54). Therefore, by particularly reducing the coverage in the first dummy inclined portion 54 of the dummy lead-out portion 52, delamination between layers in the dummy lead-out portion 52 can be effectively suppressed.

[0051] Further, the lead-out portion 17 of the internal electrode 15 has a first inclined portion 18 that is drawn out from the opposing portion 16 and inclines inward in the stacking direction as it goes from the opposing portion 16 side toward the side away from the opposing portion 16, and a second inclined portion 19 that extends from the first inclined portion 18 toward the side away from the opposing portion 16, has a gentler inclination than the first inclined portion 18, and inclines inward in the stacking direction as it goes from the opposing portion 16 side toward the side away from the opposing portion 16.

[0052] The dimension of the first inclined portion 18 in the inclined direction of the first inclined portion 18 is smaller than the dimension of the first dummy inclined portion 54 in the inclined direction of the first dummy inclined portion 54. Specifically, the dimension of the first inclined portion 18 in the inclined direction of the first inclined portion 18 is smaller than the dimension of the first dummy inclined portion 54B formed on the inner dummy electrode 5B in the inclined direction of the first dummy inclined portion 54B, and is smaller than the dimension of the first dummy inclined portion 54A formed on the outer dummy electrode 5A in the inclined direction of the first dummy inclined portion 54A.

[0053] The lead-out portion 17 and the dummy lead-out portion 52 may be greatly inclined in the vicinity of the opposing portion 16 and the dummy opposing portion 51. In the portions where these inclinations are large (the first inclined portion 18 and the first dummy inclined portion 54), delamination is considered to be more likely to occur compared to other portions. Also, the internal electrode 15 is considered to have a higher need to suppress delamination than the dummy electrode 5. However, according to such a configuration, by reducing the dimension of the first inclined portion 18, delamination in the internal electrode 15 can be suppressed. Note that in the dummy electrode 5, as described above, the coverage can be made lower than that of the internal electrode 15. Therefore, even when the dimension of the first dummy inclined portion 54 is relatively large, by reducing the coverage of the first dummy inclined portion 54, delamination in the dummy electrode 5 can be sufficiently suppressed.

[0054] The dimension of the first dummy inclined portion 54B formed on the inner dummy electrode 5B in the inclined direction of the first dummy inclined portion 54B is smaller than the dimension of the first dummy inclined portion 54A formed on the outer dummy electrode 5A in the inclined direction of the first dummy inclined portion 54A.

[0055] Thereby, among the plurality of dummy electrodes 5, delamination can be suppressed in the inner dummy electrode 5B closer to the internal electrode 15. Thereby, in the inner dummy electrode 5B, generation of delamination can be suppressed while ensuring sufficient coverage.

[0056] In FIG. 3, the dimension in the inclination direction of the first inclined portion 18 of the first inclined portion 18 is shown as d1, the dimension in the inclination direction of the first dummy inclined portion 54B formed on the inner dummy electrode 5B is shown as d2, and the dimension in the inclination direction of the first dummy inclined portion 54A of the first dummy inclined portion 54A formed on the outer dummy electrode 5A is shown as d3. The second dummy inclined portion 55 formed on the outer dummy electrode 5A is shown as the second dummy inclined portion 55A, and the second dummy inclined portion 55 formed on the inner dummy electrode 5B is shown as the second dummy inclined portion 55B.

[0057] (Measurement Method) Subsequently, the measurement method for each value will be described.

[0058] The coverage of the electrode is the ratio occupied by the metal portion in the electrode. The coverage of the electrode is measured, for example, as so-called line coverage.

[0059] When measuring the coverage of the electrode (line coverage), the laminate is polished to expose the LT cross-section (for example, the cross-section in FIG. 2) passing through the center in the width direction W of the multilayer ceramic capacitor 1. Next, the exposed cross-section is observed with a scanning electron microscope (SEM) or the like. For each region of the electrode, the dimension in the length direction L including the voids of the electrode (referred to as "length La") and the dimension in the length direction L of the actual electrode excluding the voids (referred to as "length Lb") are measured respectively. The coverage in each region of the electrode is calculated by the following formula (1).

[0060] Coverage (%) = (length Lb / length La) × 100 ··· (1)

[0061] When measuring the dimensions of the electrode, the laminate is polished to expose a predetermined cross-section (for example, the reference cross-section) at the center of the LT cross-section passing through the width direction W of the laminate 2. Next, the cross-section exposed by the scanning electron microscope is observed, and various dimensions are measured.

[0062] Note that the coverage and dimensions of the internal electrode 15 are the average values of the measured values of the plurality of internal electrodes 15.

[0063] (Method for manufacturing multilayer ceramic capacitor 1) Subsequently, the method for manufacturing the multilayer ceramic capacitor 1 of the embodiment will be described. The manufacturing method of the multilayer ceramic capacitor 1 of this embodiment is not limited as long as it satisfies the above-described requirements. However, a suitable manufacturing method includes the following steps. The details of each step will be described below.

[0064] (Internal electrode pattern forming step) First, a ceramic green sheet in which a ceramic slurry is formed into a sheet shape is prepared. On the ceramic green sheet, a pattern of the internal electrode 15 is printed with a conductor paste. Thereby, a ceramic green sheet (hereinafter referred to as "ceramic green sheet for inner layer part") on which the internal electrode 15 is disposed is obtained. Also, on the ceramic green sheet, a pattern of the dummy electrode 5 is printed with a conductor paste. Thereby, a ceramic green sheet (hereinafter referred to as "ceramic green sheet for dummy electrode lamination") on which the dummy electrode 5 is disposed is obtained. Note that the patterns of the internal electrode 15 and the dummy electrode 5 are formed by printing such as screen printing, gravure printing, and letterpress printing, for example.

[0065] When the printing method is screen printing, the height and low of the electrode coverage can be adjusted by adjusting the depth of the opening of the mesh used for screen printing for each electrode and region. The depth of the opening of the mesh is set deeper in the region where it is desired to increase the coverage, and set shallower in the region where it is desired to decrease the coverage. Also, when the printing method is gravure printing, the height and low of the electrode coverage can be adjusted by adjusting the area and volume of the opening of the gravure plate for each electrode and region. The adjustment of the area and volume of the opening can be adjusted using, for example, drawing by a laser.

[0066] The magnitude of the inclination of the electrode is adjusted, for example, by adjusting the thickness of the ceramic green sheet and the conductor paste, or by adjusting the pressing conditions when pressing the mother block described later with a hydrostatic press or the like.

[0067] (Lamination Process) Next, a ceramic green sheet for the inner layer is laminated. The ceramic green sheet for the inner layer is laminated so that the internal electrode patterns are shifted by a half pitch in the length direction L between adjacent sheets.

[0068] Next, a ceramic green sheet for dummy electrode lamination is placed on top of the uppermost layer of the inner layer ceramic green sheets laminated in a state of being shifted by a half pitch. The ceramic green sheet for dummy electrode lamination is arranged such that the pattern of the conductor paste on the uppermost layer of the ceramic green sheet and the pattern of the conductor paste on the ceramic green sheet for dummy electrode lamination overlap when viewed from the lamination direction T. The ceramic green sheet for dummy electrode lamination is laminated in, for example, two layers. Further, on top of that, a ceramic green sheet on which no conductor paste is printed is laminated as a ceramic green sheet for the outer layer.

[0069] Similarly, a ceramic green sheet for dummy electrode lamination is placed under the lowermost layer of the inner layer ceramic green sheets laminated in a state of being shifted by a half pitch. The ceramic green sheet for dummy electrode lamination is arranged such that the pattern of the conductor paste on the lowermost layer of the ceramic green sheet and the pattern of the conductor paste on the ceramic green sheet for dummy electrode lamination overlap when viewed from the lamination direction T. The ceramic green sheet for dummy electrode lamination is laminated in, for example, two layers. Further, under that, a ceramic green sheet on which no conductor paste is printed is laminated as a ceramic green sheet for the outer layer.

[0070] The ceramic green sheet for the outer layer is thermocompression bonded to the ceramic green sheet for the inner layer. Thereby, a mother block is obtained.

[0071] Note that the outer layer portion 12 is composed of a ceramic green sheet for laminating dummy electrodes and a ceramic green sheet on which no conductor paste is printed. Also, in each outer layer portion 12, the number of layers in which the ceramic green sheet for laminating dummy electrodes is laminated is not limited to two layers, and may be three or more layers. The number of layers in which the ceramic green sheet for the outer layer portion on which no conductor paste is printed is laminated may be one layer, or may be two or more layers.

[0072] (Mother block cutting process) Next, the mother block is divided along a cutting line corresponding to the dimensions of the laminate. The mother block is cut, for example, in the length direction L and the width direction W. Thereby, a plurality of rectangular parallelepiped blocks (referred to as "laminated chips") are obtained. Note that the laminated chips are preferably rounded at the corners and ridges, for example, by barrel polishing.

[0073] (Laminate firing process) Next, the laminated chips are heated in a nitrogen atmosphere at a predetermined firing temperature for a predetermined time. Thereby, the laminate 2 is obtained. (External electrode formation process) Next, external electrodes 3 are formed on each end face C of the laminate 2. Each external electrode 3 is formed so as to cover not only the end face C but also a part of the main face A and the side face B on the end face C side.

[0074] (External electrode baking process) Subsequently, the laminate 2 on which the external electrodes 3 are formed is heated in a nitrogen atmosphere at a predetermined firing temperature for a predetermined time. Thereby, the external electrodes 3 are baked onto the laminate 2.

[0075] As described above, the multilayer ceramic capacitor 1 shown in FIG. 1 is obtained.

[0076] (Effects according to the embodiment) According to this embodiment, the following effects can be obtained.

[0077] According to this embodiment, the coverage of the outer dummy electrode 5A is lower than the coverage of the internal electrode 15.

[0078] According to such a configuration, by reducing the coverage of the outer dummy electrode 5A, the adhesion between the outer dummy electrode 5A and the dielectric layer 14 can be improved, so that delamination in the outer dummy electrode 5A can be suppressed. Thereby, the reliability of the multilayer ceramic capacitor 1 can be improved. Also, by increasing the coverage of the internal electrode 15, the capacitance can be improved.

[0079] Therefore, a multilayer ceramic capacitor with high capacitance and excellent reliability can be provided.

[0080] According to this embodiment, the coverage of the outer dummy electrode 5A is lower than the coverage of the inner dummy electrode 5B.

[0081] It is considered that the risk of delamination increases as the distance from the main surface A becomes closer. However, according to such a configuration, by reducing the coverage of the outer dummy electrode 5A, delamination in the outer dummy electrode 5A can be suitably suppressed. Also, by increasing the coverage of the inner dummy electrode 5B, for example, the arrival of moisture to the internal electrode 15 can be more reliably suppressed. Thereby, the reliability of the multilayer ceramic capacitor 1 can be more suitably improved.

[0082] According to this embodiment, the coverage of the inner dummy electrode 5B is lower than the coverage of the internal electrode 15.

[0083] According to such a configuration, by reducing the coverage of the inner dummy electrode 5B, the adhesion between the inner dummy electrode 5B and the dielectric layer 14 can be improved, so that delamination in the inner dummy electrode 5B can be more suitably suppressed. By increasing the coverage of the internal electrode 15, a desired effect can be obtained without causing a decrease in capacitance.

[0084] According to this embodiment, the coverage of the outer dummy electrode 5A is preferably 40% or more and less than 60%, and the coverage of the internal electrode 15 is preferably 60% or more and 90% or less. In that case, the desired effect can be preferably obtained.

[0085] According to this embodiment, the coverage of the outer dummy electrode 5A is preferably 40% or more and less than 60%, and the coverage of the inner dummy electrode 5B is preferably 60% or more and 90% or less. In that case, the desired effect can be preferably obtained.

[0086] According to this embodiment, the coverage of the dummy lead-out portion 52 is lower than the coverage of the lead-out portion 17.

[0087] In the laminate 2, it is considered that delamination is particularly likely to occur at the dummy lead-out portion 52. Therefore, by reducing the coverage of the dummy lead-out portion 52, the occurrence of delamination at the dummy lead-out portion 52 can be effectively suppressed. By increasing the coverage of the lead-out portion 17, the coverage of the internal electrode 15 can be increased, so that the capacitance can be improved.

[0088] According to this embodiment, in the internal electrode 15, the coverage of the lead-out portion 17 is lower than the coverage of the opposing portion 16.

[0089] In the internal electrode 15, it is considered that delamination is likely to occur at the lead-out portion 17. By reducing the coverage of the lead-out portion 17, the occurrence of delamination in the internal electrode 15 can be suppressed. Also, by increasing the coverage of the opposing portion 16, the capacitance can be improved.

[0090] According to this embodiment, the coverage of the first dummy inclined portion 54 is lower than the coverage of the second dummy inclined portion 55.

[0091] The dummy lead-out portion 52 may be significantly inclined in the vicinity of the dummy facing portion 51. In the inclined portion (first dummy inclined portion 54), delamination is likely to occur. Therefore, in the first dummy inclined portion 54 of the dummy lead-out portion 52, by particularly reducing the coverage, delamination in the dummy lead-out portion 52 can be effectively suppressed.

[0092] According to the present embodiment, the dimension of the first inclined portion 18 in the inclined direction of the first inclined portion 18 is smaller than the dimension of the first dummy inclined portion 54 in the inclined direction of the first dummy inclined portion 54. Specifically, the dimension of the first inclined portion 18 in the inclined direction of the first inclined portion 18 is smaller than the dimension of the first dummy inclined portion 54B in the inclined direction of the first dummy inclined portion 54B formed on the inner dummy electrode 5B, and is smaller than the dimension of the first dummy inclined portion 54A in the inclined direction of the first dummy inclined portion 54A formed on the outer dummy electrode 5A.

[0093] The lead-out portion 17 and the dummy lead-out portion 52 may be significantly inclined in the vicinity of the facing portion 16 and the dummy facing portion 51. In the portions where these inclinations are large (the first inclined portion 18 and the first dummy inclined portion 54), delamination is considered to be more likely to occur compared to other portions. Also, the internal electrode 15 is considered to have a higher need to suppress delamination than the dummy electrode 5. However, according to such a configuration, by reducing the dimension of the first inclined portion 18, delamination in the internal electrode 15 can be suppressed. In the dummy electrode 5, as described above, the coverage can be made lower than that of the internal electrode 15. Therefore, even when the dimension of the first dummy inclined portion 54 is relatively large, by reducing the coverage of the first dummy inclined portion 54, delamination in the dummy electrode 5 can be sufficiently suppressed.

[0094] According to the present embodiment, the dimension of the first dummy inclined portion 54B formed on the inner dummy electrode 5B in the inclined direction of the first dummy inclined portion 54B is smaller than the dimension of the first dummy inclined portion 54A formed on the outer dummy electrode 5A in the inclined direction of the first dummy inclined portion 54A.

[0095] As a result, among the plurality of dummy electrodes 5, in the inner dummy electrode 5B closer to the inner electrode 15, the occurrence of delamination can be suppressed. Thereby, in the inner dummy electrode 5B, it is possible to suppress the occurrence of delamination while ensuring sufficient coverage.

[0096] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications and variations are possible.

[0097] In the above embodiment, the inner electrode 15 located closest to the first main surface AA side is the first inner electrode 15A, and the inner electrode 15 located closest to the second main surface AB side is the second inner electrode 15B. However, the present invention is not limited to this. For example, the inner electrode 15 located closest to the first main surface AA side may be the second inner electrode 15B, and the inner electrode 15 located closest to the second main surface AB side may be the first inner electrode 15A. In that case, the internal configuration of the laminate 2 is substantially the same as the internal configuration of the laminate 2 in the above embodiment, but inverted in the length direction L.

[0098] In the above embodiment, each dummy electrode 5 is connected to the external electrode 3 to which the inner electrode 15 closest to the dummy electrode 5 is connected. However, the present invention is not limited to this. The dummy electrode 5 may not be connected to any of the external electrodes 3.

[0099] In the above embodiment, two dummy electrodes 5 are arranged in each outer layer portion 12. Although a plurality of dummy electrodes 5 are arranged, the present invention is not limited to this. Three or more dummy electrodes 5 may be arranged in each outer layer portion 12. In that case, in each outer layer portion 12, the plurality of dummy electrodes 5 will include one outer dummy electrode 5A and two or more inner dummy electrodes 5B. And among the plurality of inner dummy electrodes 5B arranged in one outer layer portion 12, it is preferable that the inner dummy electrode 5B located more on the outer side in the stacking direction has a lower coverage than the inner dummy electrode 5B located more on the inner side in the stacking direction.

[0100] In this case, among the plurality of inner dummy electrodes 5B, those located more outward in the stacking direction are considered to have a higher risk of peeling. Thus, peeling of the inner dummy electrodes 5B that are more likely to peel can be suitably suppressed. Among the inner dummy electrodes 5B located more inward in the stacking direction, the risk of peeling is considered to be lower. By increasing the coverage of the inner dummy electrodes 5B with a lower risk of peeling, the reliability of the multilayer ceramic capacitor 1 can be improved.

[0101] In the above embodiment, the dummy electrodes 5 are respectively disposed in the outer layer portions 12 on the first main surface AA side and the outer layer portions 12 on the second main surface AB side. However, the dummy electrodes 5 may be disposed in at least any one of the outer layer portions 12.

[0102] In addition, the present invention includes the following combinations.

[0103] <1>A multilayer ceramic capacitor comprising: an inner layer portion including alternately stacked dielectric layers and internal electrodes; a pair of outer layer portions provided with the inner layer portion sandwiched therebetween in the stacking direction; a first main surface and a second main surface facing each other in the stacking direction; a first side surface and a second side surface facing each other in a width direction orthogonal to the stacking direction; a first end surface and a second end surface facing each other in a length direction orthogonal to the stacking direction and the width direction; an external electrode disposed in pairs on at least any one of the side surfaces and the end surfaces; wherein, in the stacking direction, a direction of viewing the main surfaces from the central portion of the stacking body in the stacking direction is defined as the outer side in the stacking direction, and a direction of viewing the central portion of the stacking body in the stacking direction from the main surfaces is defined as the inner side in the stacking direction. The stacking body has a plurality of dummy electrodes that are electrodes not contributing to the formation of capacitance and are disposed more outward in the stacking direction than the internal electrodes. The plurality of dummy electrodes include an outer dummy electrode disposed most outward in the stacking direction among the plurality of dummy electrodes and an inner dummy electrode disposed more inward in the stacking direction than the outer dummy electrode, and the coverage of the outer dummy electrode is lower than the coverage of the internal electrode.

[0104] <2>The coverage of the outer dummy electrode is lower than that of the inner dummy electrode, the multilayer ceramic capacitor according to <1>.

[0105] <3>The coverage of the inner dummy electrode is lower than that of the internal electrode, the multilayer ceramic capacitor according to <1> or <2>.

[0106] <4>The coverage of the outer dummy electrode is 40% or more and less than 60%, and the coverage of the internal electrode is 60% or more and 90% or less, the multilayer ceramic capacitor according to any one of <1> to <3>.

[0107] <5>The coverage of the outer dummy electrode is 40% or more and less than 60%, and the coverage of the inner dummy electrode is 60% or more and 90% or less, the multilayer ceramic capacitor according to any one of <2> to <4>.

[0108] <6>The internal electrode has a facing portion facing the internal electrode adjacent in the stacking direction, and a lead-out portion drawn from the facing portion and connected to the external electrode. Each dummy electrode has a dummy facing portion overlapping the facing portion closest to the first main surface side in the stacking direction, and a dummy lead-out portion drawn from the dummy facing portion to the external electrode side where the outermost lead-out portion in the stacking direction of the lead-out portions is connected. The coverage of the dummy lead-out portion is lower than that of the lead-out portion, the multilayer ceramic capacitor according to any one of <1> to <5>.

[0109] <7>The coverage of the lead-out portion is lower than that of the facing portion, the multilayer ceramic capacitor according to <6>.

[0110] <8>The dummy lead-out portion has a first dummy inclined portion that is drawn out from the dummy facing portion and is inclined inward in the stacking direction as it goes from the dummy facing portion side toward the side away from the dummy facing portion, and a second dummy inclined portion that extends from the first dummy inclined portion toward the side away from the dummy facing portion, has a gentler inclination than the first dummy inclined portion, and is inclined inward in the stacking direction as it goes from the dummy facing portion side toward the side away from the dummy facing portion. The coverage of the first dummy inclined portion is lower than the coverage of the second dummy inclined portion. The multilayer ceramic capacitor according to <6> or <7>.

[0111] <9>The lead-out portion has a first inclined portion that is drawn out from the facing portion and is inclined inward in the stacking direction as it goes from the facing portion side toward the side away from the facing portion, and a second inclined portion that extends from the first inclined portion toward the side away from the facing portion, has a gentler inclination than the first inclined portion, and is inclined inward in the stacking direction as it goes from the facing portion side toward the side away from the facing portion. The dimension of the first inclined portion in the inclination direction of the first inclined portion is smaller than the dimension of the first dummy inclined portion in the inclination direction of the first dummy inclined portion. The multilayer ceramic capacitor according to <8>.

[0112] <10>The dimension of the first dummy inclined portion formed on the inner dummy electrode in the inclination direction of the first dummy inclined portion is smaller than the dimension of the first dummy inclined portion formed on the outer dummy electrode in the inclination direction of the first dummy inclined portion. The multilayer ceramic capacitor according to <8> or <9>.

Explanation of Reference Numerals

[0113] 1 Multilayer ceramic capacitor 2 Stacked body 3 External electrode 5 Dummy electrode 5A Outer dummy electrode 5B Inner dummy electrode 14 Dielectric layer 15 Internal electrode 16 Facing portion 17 Lead-out portion 18 First inclined portion 19 Second inclined portion 51 Dummy facing portion 52 Dummy lead-out portion 54 First dummy inclined portion 55 Second dummy inclined portion AA First main surface AB Second main surface BA First side surface BB Second side surface CA First end surface CB Second end surface

Claims

1. An inner layer portion including dielectric layers and internal electrodes laminated alternately, a pair of outer layer portions provided with the inner layer portion interposed therebetween in the lamination direction, a first main surface and a second main surface facing each other in the lamination direction, a first side surface and a second side surface facing each other in a width direction orthogonal to the lamination direction, and a first end surface and a second end surface facing each other in a length direction orthogonal to the lamination direction and the width direction, and a laminate having; External electrodes arranged in pairs on at least one of each of the side surfaces and each of the end surfaces; A multilayer ceramic capacitor comprising: Among the lamination directions, a direction in which each main surface is viewed from a central portion of the laminate in the lamination direction is defined as an outer side in the lamination direction, and among the lamination directions, a direction in which the central portion of the laminate in the lamination direction is viewed from each main surface is defined as an inner side in the lamination direction. The laminate has a plurality of dummy electrodes that are electrodes not contributing to the formation of capacitance and are arranged on the outer side in the lamination direction than the internal electrodes. The plurality of dummy electrodes include an outer dummy electrode arranged on the outermost side in the lamination direction among the plurality of dummy electrodes, and an inner dummy electrode arranged on the inner side in the lamination direction than the outer dummy electrode. The coverage of the outer dummy electrode is lower than the coverage of the internal electrode, a multilayer ceramic capacitor.

2. The coverage of the outer dummy electrode is lower than the coverage of the inner dummy electrode, the multilayer ceramic capacitor according to claim 1.

3. The coverage of the inner dummy electrode is lower than the coverage of the internal electrode, the multilayer ceramic capacitor according to claim 2.

4. The coverage of the outer dummy electrode is 40% or more and less than 60%, and the coverage of the internal electrode is 60% or more and 90% or less, the multilayer ceramic capacitor according to any one of claims 1 to 3.

5. The coverage of the outer dummy electrode is 40% or more and less than 60%, and the coverage of the inner dummy electrode is 60% or more and 90% or less, the multilayer ceramic capacitor according to claim 2 or 3.

6. The internal electrode has a facing portion facing the internal electrode adjacent in the lamination direction, and a lead-out portion drawn from the facing portion and connected to the external electrode. Each of the dummy electrodes has a dummy opposing portion that overlaps with the opposing portion on the most first main surface side in the stacking direction, and a dummy lead portion that is drawn from the dummy opposing portion to the external electrode side to which the outermost lead portion in the stacking direction among the lead portions is connected. The coverage of the dummy lead portion is lower than the coverage of the lead portion. The multilayer ceramic capacitor according to any one of claims 1 to 3. **Claim 7** The coverage of the lead portion is lower than the coverage of the opposing portion. The multilayer ceramic capacitor according to claim 6. **Claim 8** The dummy lead portion is drawn from the dummy opposing portion and has a first dummy inclined portion that inclines inward in the stacking direction as it goes from the dummy opposing portion side toward the side away from the dummy opposing portion, and a second dummy inclined portion that extends from the first dummy inclined portion to the side away from the dummy opposing portion and inclines inward in the stacking direction with a gentler inclination than the first dummy inclined portion as it goes from the dummy opposing portion side toward the side away from the dummy opposing portion. The coverage of the first dummy inclined portion is lower than the coverage of the second dummy inclined portion. The multilayer ceramic capacitor according to claim 6. **Claim 9** The lead portion is drawn from the opposing portion and has a first inclined portion that inclines inward in the stacking direction as it goes from the opposing portion side toward the side away from the opposing portion, and a second inclined portion that extends from the first inclined portion to the side away from the opposing portion and inclines inward in the stacking direction with a gentler inclination than the first inclined portion as it goes from the opposing portion side toward the side away from the opposing portion. The dimension of the first inclined portion in the inclined direction of the first inclined portion is smaller than the dimension of the first dummy inclined portion in the inclined direction of the first dummy inclined portion. The multilayer ceramic capacitor according to claim 8. **Claim 10** The dimension of the first dummy inclined portion formed on the inner dummy electrode in the inclined direction of the first dummy inclined portion is smaller than the dimension of the first dummy inclined portion formed on the outer dummy electrode in the inclined direction of the first dummy inclined portion. The multilayer ceramic capacitor according to claim 8.

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