阅读说明：本技术 层叠陶瓷电子部件 (Laminated ceramic electronic component ) 是由 高桥武文 于 2021-03-23 设计创作，主要内容包括：本发明提供一种即使进行外部电极层的薄层化也能够抑制外部电极层的耐水性的下降的层叠陶瓷电子部件。层叠陶瓷电子部件(1)具备层叠体(10)和包含作为烧成层的基底电极层(415)的外部电极层(41)。层叠体具有包含陶瓷层(20)和内部导体层(31、32)的内层部(100)以及包含陶瓷层的外层部(101、102),基底电极层(415)具有与内层部邻接的内层电极部(410)和与外层部分别邻接的外层电极部(411、412)。外层电极部从层叠体的端面起依次具有高含有区域(411H、412H)和低含有区域(411L、412L),高含有区域中的金属的含有率高于低含有区域中的金属的含有率。(The invention provides a laminated ceramic electronic component which can restrain the reduction of the water resistance of an external electrode layer even if the external electrode layer is thinned. A laminated ceramic electronic component (1) is provided with a laminate (10) and an external electrode layer (41) that includes a base electrode layer (415) as a fired layer. The laminate comprises an inner layer section (100) comprising a ceramic layer (20) and inner conductor layers (31, 32), and outer layer sections (101, 102) comprising ceramic layers, and the base electrode layer (415) comprises an inner layer electrode section (410) adjacent to the inner layer section and outer layer electrode sections (411, 412) adjacent to the outer layer sections, respectively. The outer layer electrode section has high-content regions (411H, 412H) and low-content regions (411L, 412L) in this order from the end face of the laminate, and the content of metal in the high-content regions is higher than the content of metal in the low-content regions.)

1. A laminated ceramic electronic component includes:

a laminate having a plurality of ceramic layers and internal conductor layers laminated thereon, the laminate having a 1 st main surface and a 2 nd main surface facing each other in a lamination direction, a 1 st side surface and a 2 nd side surface facing each other in a width direction intersecting the lamination direction, and a 1 st end surface and a 2 nd end surface facing each other in a longitudinal direction intersecting the lamination direction and the width direction;

a 1 st external electrode layer disposed on the 1 st end surface of the laminate and connected to the internal conductor layer; and

a 2 nd external electrode layer disposed on the 2 nd end face of the laminate and connected to the internal conductor layer,

the 1 st external electrode layer includes:

a 1 st base electrode layer which is a fired layer containing a metal and glass; and

a plating layer covering the 1 st base electrode layer,

the 2 nd external electrode layer includes:

a 2 nd base electrode layer which is a fired layer containing metal and glass; and

a plating layer covering the 2 nd base electrode layer,

the laminate comprises:

an inner layer portion including a part of the plurality of ceramic layers and the internal conductor layer; and

two outer layer sections disposed so as to sandwich the inner layer section and each including a portion other than the portion of the plurality of ceramic layers,

the 1 st base electrode layer has:

a 1 st inner electrode section adjacent to the inner layer section of the laminate; and

two 1 st outer layer electrode portions adjacent to the two outer layer portions of the laminate, respectively,

the 2 nd base electrode layer has:

a 2 nd inner electrode section adjacent to the inner layer section of the laminate; and

two 2 nd outer layer electrode sections adjacent to the two outer layer sections of the laminate, respectively,

in the longitudinal direction, the maximum thickness of each of the 1 st inner electrode portion, the two 1 st outer electrode portions, the 2 nd inner electrode portion, and the two 2 nd outer electrode portions is 1 μm or more and 40 μm or less, the thickness of each of the two 1 st outer electrode portions is thinner than the thickness of the 1 st inner electrode portion, and the thickness of each of the two 2 nd outer electrode portions is thinner than the thickness of the 2 nd inner electrode portion,

the two 1 st outer layer electrode portions each have a 1 st outer layer high content region and a 1 st outer layer low content region in this order from the 1 st end face of the laminate,

the two 2 nd outer layer electrode portions each have a 2 nd outer layer high content region and a 2 nd outer layer low content region in this order from the 2 nd end face of the laminate,

the content of the metal in the 1 st outer layer high content region is higher than the content of the metal in the 1 st outer layer low content region,

the content of the metal in the 2 nd outer layer high content region is higher than the content of the metal in the 2 nd outer layer low content region.

2. The laminated ceramic electronic component according to claim 1,

the content of glass in the 1 st outer layer high content region is lower than the content of glass in the 1 st outer layer low content region,

the content of glass in the 2 nd outer layer high content region is lower than the content of glass in the 2 nd outer layer low content region.

3. The laminated ceramic electronic component according to claim 1 or 2,

a 1 st metal diffusion base part is disposed in at least a part of each of the two outer layer parts adjacent to the 1 st outer layer electrode part, and a part of the 1 st metal diffusion base part is metal-diffused into the 1 st outer layer high content region,

a 2 nd metal diffusion base is disposed in at least a part of a portion adjacent to the 2 nd outer layer electrode section in each of the two outer layer sections, and a part of the 2 nd metal diffusion base is metal-diffused into the 2 nd outer layer high content region.

4. The laminated ceramic electronic component according to claim 3,

the 1 st metal diffusion base and the 2 nd metal diffusion base each include a plurality of metal films laminated at intervals of 0.2 μm or more and 1 μm or less in the lamination direction.

5. The laminated ceramic electronic component according to claim 3 or 4,

the 1 st outer layer high content region contains the same metal component as that of the 1 st metal diffusion base, whereby the content of the metal in the 1 st outer layer high content region is higher than that in the 1 st outer layer low content region,

the 2 nd outer layer high content region contains the same metal component as that of the 2 nd metal diffusion base, whereby the content of the metal in the 2 nd outer layer high content region is higher than that in the 2 nd outer layer low content region.

6. The laminated ceramic electronic component according to claim 5,

the metal contained in each of the 1 st base electrode layer and the 2 nd base electrode layer contains Cu as a main component,

the metal in which the 1 st metal diffusion base and the 2 nd metal diffusion base are each metal-diffused is mainly composed of Ni,

the content of Ni in the 1 st outer layer high-content region is higher than the content of Ni in the 1 st outer layer low-content region,

the content of Ni in the 2 nd outer layer high content region is higher than the content of Ni in the 2 nd outer layer low content region.

7. The laminated ceramic electronic component according to any one of claims 1 to 6,

the 1 st inner layer electrode portion has a 1 st inner layer high content region and a 1 st inner layer low content region in this order from the 1 st end face of the laminate,

the 2 nd inner layer electrode section has a 2 nd inner layer high content region and a 2 nd inner layer low content region in this order from the 2 nd end face of the laminate,

the content of the metal in the 1 st inner layer high content region is higher than the content of the metal in the 1 st inner layer low content region,

the content ratio of the metal in the 2 nd inner layer high content region is higher than the content ratio of the metal in the 2 nd inner layer low content region,

the 1 st outer layer high-content area is connected with the 1 st inner layer high-content area,

the 2 nd outer layer high content area is connected with the 2 nd inner layer high content area.

8. The laminated ceramic electronic component according to any one of claims 1 to 7,

the 1 st outer layer high content region is arranged in the stacking direction from a portion in contact with a boundary between the outer layer portion and the inner layer portion on the 1 st main surface side of the two outer layer portions to a portion in contact with the 1 st main surface,

the 2 nd outer layer high content region is arranged from a portion in contact with a boundary between the outer layer portion and the inner layer portion on the 2 nd main surface side of the two outer layer portions to a portion in contact with the 2 nd main surface in the lamination direction.

9. The laminated ceramic electronic component according to claim 4,

the 1 st base electrode layer has a 1 st extension electrode portion extending from the 1 st end surface to a part of the 1 st main surface and a part of the 2 nd main surface of the laminate,

the 2 nd base electrode layer has a 2 nd extension electrode portion extending from the 2 nd end surface to a part of the 1 st main surface and a part of the 2 nd main surface of the laminate,

when the lengths of the plurality of metal films and the lengths of the 1 st and 2 nd extended electrode portions are set to the lengths in the longitudinal direction, the length of the plurality of metal films in the 1 st metal diffusion base portion is shorter than the length of the 1 st extended electrode portion, and the length of the plurality of metal films in the 2 nd metal diffusion base portion is shorter than the length of the 2 nd extended electrode portion.

10. The laminated ceramic electronic component according to claim 4,

the internal conductor layer has:

a 1 st internal conductor layer connected to the 1 st base electrode layer at the 1 st end surface of the laminate; and

a 2 nd inner conductor layer connected to the 2 nd base electrode layer at the 2 nd end face of the laminate,

the plurality of metal films in the 1 st metal diffusion base portion are arranged so as to be connected to the 1 st base electrode layer at the 1 st end face and so as not to overlap with the 2 nd inner conductor layer in the stacking direction,

the plurality of metal films in the 2 nd metal diffusion base portion are arranged so as to be connected to the 2 nd base electrode layer at the 2 nd end face and so as not to overlap with the 1 st inner conductor layer in the stacking direction.

11. The laminated ceramic electronic component according to claim 4,

the thicknesses of the plurality of metal films are equal to or less than the thickness of the internal conductor layer.

12. The laminated ceramic electronic component according to any one of claims 1 to 11,

the ceramic layer is a dielectric layer,

the internal conductor layer has:

a 1 st internal electrode layer connected to the 1 st external electrode layer; and

a 2 nd inner electrode layer connected to the 2 nd outer electrode layer,

the 1 st internal electrode layer and the 2 nd internal electrode layer face each other with a part of the dielectric layer interposed therebetween.

Technical Field

The present invention relates to a laminated ceramic electronic component.

Background

As a surface-mounted electronic component, a laminated ceramic electronic component using ceramic is known. For example, patent document 1 discloses a laminated ceramic capacitor as such a laminated ceramic electronic component. Such a multilayer ceramic capacitor includes a multilayer body in which a plurality of ceramic layers and a plurality of internal electrode layers are laminated, and external electrode layers provided at respective ends of the multilayer body and connected to the plurality of internal electrode layers. The external electrode layer has a base electrode layer and a plating layer covering the base electrode layer.

As a method for forming the underlying electrode layer, there is known a method in which an electrode material is applied to an end portion of a laminate by dipping the end portion of the laminate into a paste-like electrode material containing a metal such as Cu and glass, and then the electrode material is fired. Thereby, an underlying electrode layer as a fired layer was formed.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-76582

In view of downsizing a multilayer ceramic electronic component such as a multilayer ceramic capacitor, thinning of an external electrode layer has been studied. As a result of the accumulation of studies, experiments, and simulations by the inventors, a new finding was obtained that when the base electrode layer of the external electrode layer is made thinner, the water resistance of the laminated ceramic electronic component is lowered. This is considered to be due to the following reason.

When the base electrode layer is formed by a dipping method or the like, when the end portions of the laminate are dipped in the electrode material, the thickness of the base electrode layer at the ridge line portions of the end portions of the laminate becomes thinner than the thickness of the base electrode layer at the central portion of the end portions of the laminate due to the surface tension of the paste-like electrode material.

In addition, when the underlying electrode layer is fired, a variation in grain growth of a metal such as Cu occurs, and a portion having a low metal content may occur.

It is considered that, when the base electrode layer is made thinner, a problem arises in that moisture penetrates through a portion having a low metal content, such as a ridge portion at an end portion of the multilayer body in the base electrode layer. For example, when forming the plating layer, it is considered that the plating solution penetrates into the laminate from the thin base electrode layer having a low metal content at the ridge portion of the end portion of the laminate. Alternatively, when the base electrode layer is thin at the ridge portion at the end of the laminate, the plating layer may not be formed at the ridge portion at the end of the laminate. In this case, even after the plating layer is formed, moisture in the atmosphere may infiltrate into the laminate from the base electrode layer at the ridge portion of the end portion of the laminate where the plating layer is not formed. In the present application, moisture is a concept including a plating solution, and water resistance is a concept including resistance to the plating solution.

It is considered that, when the moisture thus infiltrated infiltrates into the internal conductor layers in the multilayer body, the electrical characteristics of the multilayer ceramic electronic component are degraded.

Disclosure of Invention

Problems to be solved by the invention

An object of the present invention is to provide a laminated ceramic electronic component including an external electrode layer including a fired layer, in which a decrease in water resistance of the external electrode layer can be suppressed even when the external electrode layer is made thinner.

Means for solving the problems

The laminated ceramic electronic component according to the present invention includes: a laminate having a plurality of ceramic layers and internal conductor layers laminated thereon, the laminate having a 1 st main surface and a 2 nd main surface facing each other in a lamination direction, a 1 st side surface and a 2 nd side surface facing each other in a width direction intersecting the lamination direction, and a 1 st end surface and a 2 nd end surface facing each other in a longitudinal direction intersecting the lamination direction and the width direction; a 1 st external electrode layer disposed on the 1 st end surface of the laminate and connected to the internal conductor layer; and a 2 nd external electrode layer disposed on the 2 nd end surface of the laminate and connected to the internal conductor layer.

The 1 st external electrode layer includes: a 1 st base electrode layer which is a fired layer containing a metal and glass; and a plating layer covering the 1 st base electrode layer, the 2 nd external electrode layer having: a 2 nd base electrode layer which is a fired layer containing metal and glass; and a plating layer covering the 2 nd base electrode layer.

The laminate comprises: an inner layer portion including a part of the plurality of ceramic layers and the internal conductor layer; and two outer layer portions arranged so as to sandwich the inner layer portion and each including a portion other than the portion of the plurality of ceramic layers, wherein the 1 st underlying electrode layer includes: a 1 st inner electrode section adjacent to the inner layer section of the laminate; and two 1 st outer layer electrode portions adjacent to the two outer layer portions of the laminate, respectively, the 2 nd base electrode layer having: a 2 nd inner electrode section adjacent to the inner layer section of the laminate; and two 2 nd outer layer electrode portions adjacent to the two outer layer portions of the laminate, respectively.

In the longitudinal direction, the maximum thickness of each of the 1 st inner electrode portion, the two 1 st outer electrode portions, the 2 nd inner electrode portion, and the two 2 nd outer electrode portions is 1 μm or more and 40 μm or less, the thickness of each of the two 1 st outer electrode portions is thinner than the thickness of the 1 st inner electrode portion, and the thickness of each of the two 2 nd outer electrode portions is thinner than the thickness of the 2 nd inner electrode portion. The two 1 st outer-layer electrode portions each have a 1 st outer-layer high-content region and a 1 st outer-layer low-content region in this order from the 1 st end face of the laminate, and the content of metal in the 1 st outer-layer high-content region is higher than the content of metal in the 1 st outer-layer low-content region. The two 2 nd outer layer electrode portions each have a 2 nd outer layer high content region and a 2 nd outer layer low content region in this order from the 2 nd end face of the laminate, and the content ratio of the metal in the 2 nd outer layer high content region is higher than the content ratio of the metal in the 2 nd outer layer low content region.

Effects of the invention

According to the present invention, in a laminated ceramic electronic component including an external electrode layer including a fired layer, even if the external electrode layer is made thinner, it is possible to suppress a decrease in water resistance of the external electrode layer.

Drawings

Fig. 1 is a perspective view showing a multilayer ceramic capacitor according to the present embodiment.

Fig. 2 is a sectional view of the laminated ceramic capacitor shown in fig. 1 taken along line II-II.

Fig. 3 is a sectional view of the laminated ceramic capacitor shown in fig. 2 taken along line III-III.

Fig. 4 is an enlarged cross-sectional view of a portion a corresponding to the cross-section of the multilayer ceramic capacitor shown in fig. 2, which is an example of actual observation, after firing of the base electrode layer of the external electrode layer and before forming the plating layer.

Fig. 5 is an enlarged cross-sectional view of a portion a of the cross-section of the multilayer ceramic capacitor shown in fig. 2, which corresponds to the portion a of the external electrode layer after firing the base electrode layer and before forming the plating layer, and is another example of actual observation.

Fig. 6 is a cross-sectional view of a multilayer ceramic capacitor according to a modification of the present embodiment, and corresponds to a line II-II in fig. 1.

Fig. 7 is a sectional view taken along line VII-VII of the laminated ceramic capacitor shown in fig. 6.

Description of the reference numerals

1: a laminated ceramic capacitor (laminated ceramic electronic component);

10: a laminate;

20: a dielectric layer (ceramic layer);

30: internal electrode layers (internal conductor layers);

31: 1 st internal electrode layer;

311: a 1 st counter electrode section;

312: 1 st leading electrode part;

32: 2 nd internal electrode layer;

321: a 2 nd counter electrode section;

322: a 2 nd lead electrode portion;

40: an external electrode;

41: 1 st external electrode;

41 TS: a 1 st extension electrode section;

42 TS: a 2 nd extension electrode section;

410: 1 st inner electrode part;

410H: 1 st inner high-content region;

410L: 1 st inner low content region;

411. 412: 1 st outer electrode part;

411H, 412H: 1 st outer high content region;

411L, 412L: 1 st outer low content region;

415: 1 st base electrode layer;

416: 1 st plating layer;

42: a 2 nd external electrode;

420: a 2 nd inner electrode part;

420H, the weight ratio of the mixture to the water: 2 nd inner high-content region;

420L: 2 nd inner low content region;

421. 422: a 2 nd outer electrode part;

421H, 422H: 2 nd outer high content region;

421L, 422L: 2 nd outer low content region;

425: the 2 nd base electrode layer;

426: 2 nd plating layer;

50: a metal diffusion base;

511. 512: 1 st metal diffusion base;

521. 522: a 2 nd metal diffusion base;

50M: a metal film;

100: an inner layer portion;

101: the 1 st outer layer part;

102: the 2 nd outer layer part;

l: a length direction;

t: a stacking direction;

w: a width direction;

LS 1: 1 st end face;

LS 2: a 2 nd end surface;

TS 1: a 1 st main surface;

TS 2: a 2 nd main surface;

WS 1: the 1 st side;

WS 2: side 2.

Detailed Description

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals.

Fig. 1 is a perspective view showing a multilayer ceramic capacitor according to the present embodiment, and fig. 2 is a sectional view taken along line II-II of the multilayer ceramic capacitor shown in fig. 1. Fig. 3 is a sectional view of the laminated ceramic capacitor shown in fig. 2 taken along line III-III. The multilayer ceramic capacitor 1 shown in fig. 1 to 3 includes a multilayer body 10 and an external electrode layer 40. A laminated ceramic capacitor is an example of the laminated ceramic electronic component of the present invention.

Fig. 1 to 3 show an XYZ rectangular coordinate system. The X direction is the longitudinal direction L of the multilayer ceramic capacitor 1 and the multilayer body 10, the Y direction is the width direction W of the multilayer ceramic capacitor 1 and the multilayer body 10, and the Z direction is the stacking direction T of the multilayer ceramic capacitor 1 and the multilayer body 10. Thus, the profile shown in fig. 2 is also referred to as LT profile.

The longitudinal direction L, the width direction W, and the stacking direction T are not necessarily orthogonal to each other, and may be orthogonal to each other.

The laminate 10 is substantially rectangular parallelepiped in shape, and has a 1 st main surface TS1 and a 2 nd main surface TS2 facing each other in the lamination direction T, a 1 st side surface WS1 and a 2 nd side surface WS2 facing each other in the width direction W, and a 1 st end surface LS1 and a 2 nd end surface LS2 facing each other in the longitudinal direction L.

The corners and ridge portions of the laminate 10 are rounded. The corner portion is a portion where three surfaces of the laminate 10 intersect, and the ridge portion is a portion where two surfaces of the laminate 10 intersect.

As shown in fig. 2, the stacked body 10 includes a plurality of dielectric layers 20, a plurality of internal electrode layers 30, and a plurality of metal diffusion bases 50 stacked in the stacking direction T. The laminate 10 includes an inner layer 100 and a 1 st outer layer 101 and a 2 nd outer layer 102 arranged to sandwich the inner layer 100 in the lamination direction T. The dielectric layers 20 are examples of the ceramic layers of the present invention, and the internal electrode layers 30 are examples of the internal conductor layers of the present invention.

The inner layer portion 100 includes a plurality of internal electrode layers 30 and a plurality of dielectric layers 20. In the inner layer portion 100, the plurality of internal electrode layers 30 are arranged to face each other with the dielectric layer 20 interposed therebetween. The inner layer 100 generates a capacitance, and functions substantially as a capacitor.

The 1 st outer layer section 101 is disposed on the 1 st main surface TS1 side of the laminate 10, and the 2 nd outer layer section 102 is disposed on the 2 nd main surface TS2 side of the laminate 10. More specifically, the 1 st outer layer section 101 is disposed between the inner electrode layer 30 closest to the 1 st main surface TS1 among the plurality of inner electrode layers 30 and the 1 st main surface TS1, and the 2 nd outer layer section 102 is disposed between the inner electrode layer 30 closest to the 2 nd main surface TS2 among the plurality of inner electrode layers 30 and the 2 nd main surface TS 2. The 1 st outer layer portion 101 and the 2 nd outer layer portion 102 do not include the internal electrode layer 30, and each include a portion of the plurality of dielectric layers 20 other than a portion for the inner layer portion 100. The 1 st outer layer portion 101 and the 2 nd outer layer portion 102 function as a protective layer of the inner layer portion 100. The 1 st outer layer portion 101 and the 2 nd outer layer portion 102 include a plurality of metal diffusion base portions 50.

As the material of the dielectric layer 20, for example, a material containing BaTiO as a main component can be used₃、CaTiO₃、SrTiO₃Or CaZrO₃And the like. As a material of the dielectric layer 20, an Mn compound, an Fe compound, a Cr compound, a Co compound, an Ni compound, or the like may be added as a subcomponent.

The thickness of the dielectric layer 20 is not particularly limited, and may be, for example, 0.2 μm or more and 1.0 μm or less, and preferably 0.3 μm or more and 0.5 μm or less. The number of dielectric layers 20 is not particularly limited, and may be, for example, 15 to 700. The number of the dielectric layers 20 is the total number of the dielectric layers in the inner layer portion and the outer layer portion.

The plurality of internal electrode layers 30 include a 1 st internal electrode layer 31 and a 2 nd internal electrode layer 32. The 1 st internal electrode layer 31 includes a counter electrode portion 311 and a lead electrode portion 312, and the 2 nd internal electrode layer 32 includes a counter electrode portion 321 and a lead electrode portion 322.

The opposite electrode portion 311 and the opposite electrode portion 321 face each other with the dielectric layer 20 interposed therebetween in the lamination direction T of the laminate 10. The shapes of the counter electrode portion 311 and the counter electrode portion 321 are not particularly limited, and may be, for example, substantially rectangular. The counter electrode portion 311 and the counter electrode portion 321 generate capacitance, and substantially function as a capacitor.

The lead electrode portion 312 extends from the opposite electrode portion 311 toward the 1 st end face LS1 of the laminate 10 and is exposed at the 1 st end face LS 1. The lead electrode portion 322 extends from the opposite electrode portion 321 toward the 2 nd end surface LS2 of the laminate 10 and is exposed at the 2 nd end surface LS 2. The shapes of the lead electrode portion 312 and the lead electrode portion 322 are not particularly limited, and may be, for example, a substantially rectangular shape or a shape of a counter electrode to which a lead electrode having a width narrower than that of the counter electrode 311 is connected, that is, a so-called racket (racket) shape.

The 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 contain metal Ni as a main component. The 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 may contain, for example, at least one selected from metals such as Cu, Ag, Pd, and Au, or alloys containing at least one of these metals such as Ag — Pd alloys as a main component, or may contain at least one selected from metals such as Cu, Ag, Pd, and Au, or alloys containing at least one of these metals such as Ag — Pd alloys as a component other than the main component. Further, the 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 may contain, as components other than the main component, particles of a dielectric having the same composition system as the ceramic contained in the dielectric layer 20. In the present specification, the metal as the main component is defined as the metal component having the highest weight%.

The thickness of the 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 is not particularly limited, and may be, for example, 0.2 μm or more and 2.0 μm or less. The number of the 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 is not particularly limited, and may be, for example, 15 or more and 700 or less.

Metal diffusion base 50 has 1 st metal diffusion bases 511 and 512 and 2 nd metal diffusion bases 521 and 522.

The 1 st metal diffusion base 511 is disposed at least partially in the vicinity of the 1 st end surface LS1 in the 1 st outer layer section 101 of the laminate 10, and the 2 nd metal diffusion base 521 is disposed at least partially in the vicinity of the 2 nd end surface LS2 in the 1 st outer layer section 101. The 1 st metal diffusion base 512 is disposed at least partially in the vicinity of the 1 st end surface LS1 in the 2 nd outer layer section 102 of the laminate 10, and the 2 nd metal diffusion base 522 is disposed at least partially in the vicinity of the 2 nd end surface LS2 in the 2 nd outer layer section 102.

The 1 st metal diffusion bases 511 and 512 and the 2 nd metal diffusion bases 521 and 522 have a plurality of metal films 50M. The shape of the metal film 50M is not particularly limited, and may be, for example, substantially rectangular as shown in fig. 3. The plurality of metal films 50M are stacked in the stacking direction T of the stack 10 with the dielectric layer 20 interposed therebetween. The interval between the plurality of metal films at 50M is not particularly limited, and may be 0.2 μ M or more and 1.0 μ M or less, and preferably 0.3 μ M or more and 0.5 μ M or less.

The thickness of the metal film 50M may be equal to the thickness of the internal electrode layer 30, or may be thinner than the thickness of the internal electrode layer 30.

The length of the metal film 50M in the 1 st metal diffusion bases 511 and 512 may be equal to the length of the 1 st extension electrode portion 41TS in the 1 st external electrode layer 41 described later, or may be shorter than the length of the 1 st extension electrode portion 41 TS. The length of the metal film 50M in the 2 nd metal diffusion base 521 and 522 may be equal to the length of the 2 nd extension electrode portion 42TS in the 2 nd external electrode layer 42 described later, or may be shorter than the length of the 2 nd extension electrode portion 42 TS. The 1 st extension electrode portion 41TS is a portion of the 1 st outer electrode layer 41 described later which extends from the 1 st end surface LS1 to a portion of the 1 st main surface TS1 and a portion of the 2 nd main surface TS2 of the laminate 10, and the 2 nd extension electrode portion 42TS is a portion of the 2 nd outer electrode layer 42 described later which extends from the 2 nd end surface LS2 to a portion of the 1 st main surface TS1 and a portion of the 2 nd main surface TS2 of the laminate 10. The length of the metal film 50M, the length of the 1 st extended electrode portion 41TS, and the length of the 2 nd extended electrode portion 42TS are the lengths in the longitudinal direction L of the laminate 10.

The plurality of metal films 50M in the 1 st metal diffusion bases 511 and 512 connected to the 1 st external electrode layer 41 may be arranged so as not to overlap with the 2 nd internal electrode layer 32 in the stacking direction T of the stacked body 10. The plurality of metal films 50M in the 2 nd metal diffusion bases 521 and 522 connected to the 2 nd external electrode layer 42 may be arranged so as not to overlap with the 1 st internal electrode layer 31 in the stacking direction T of the stacked body 10.

The metal film 50M contains metal Ni as a main component. The metal film 50M may contain, for example, at least one selected from metals such as Cu, Ag, Pd, and Au, or alloys such as Ag — Pd alloys containing at least one of these metals as a main component, or may contain at least one selected from metals such as Cu, Ag, Pd, and Au, or alloys such as Ag — Pd alloys containing at least one of these metals as a component other than the main component. Further, the metal film 50M may contain, as a component other than the main component, particles of a dielectric having the same composition system as the ceramic contained in the dielectric layer 20.

Thus, at the time of firing of the 1 st and 2 nd external electrode layers 41 and 42, the 1 st metal diffusion base 511 causes metal diffusion of metal Ni to the 1 st outer layer electrode portion 411 described later, the 1 st metal diffusion base 512 causes metal diffusion of metal Ni to the 1 st outer layer electrode portion 412 described later, the 2 nd metal diffusion base 521 causes metal diffusion of metal Ni to the 2 nd outer layer electrode portion 421, and the 2 nd metal diffusion base 522 causes metal diffusion of metal Ni to the 2 nd outer layer electrode portion 422. As a result, a 1 st outer layer high content region 411H described later is formed in the 1 st outer layer electrode portion 411, a 1 st outer layer high content region 412H described later is formed in the 1 st outer layer electrode portion 412, a 2 nd outer layer high content region 421H described later is formed in the 2 nd outer layer electrode portion 421, and a 2 nd outer layer high content region 422H described later is formed in the 2 nd outer layer electrode portion 422. Further, metal diffusion is performed on part of metal Ni in 1 st metal diffusion bases 511 and 512 and 2 nd metal diffusion bases 521 and 522.

The dimension of the laminate 10 is not particularly limited, and for example, the length L1 in the longitudinal direction L may be 0.1mm or more and 10mm or less, the width W1 in the width direction W may be 0.05mm or more and 10mm or less, and the thickness T1 in the laminate direction T may be 0.05mm or more and 10mm or less, preferably, the length L1 in the longitudinal direction L may be 0.1mm or more and 1.2mm or less, the width W1 in the width direction W may be 0.1mm or more and 0.7mm or less, the thickness T1 in the laminate direction T may be 0.1mm or more and 0.7mm or less, and more preferably, the length L1 in the longitudinal direction L may be 0.2mm or more and 0.5mm or less, the width W1 in the width direction W may be 0.1mm or more and 0.3mm or less, and the thickness T1 in the laminate direction T may be 0.1mm or more and 0.3mm or less. The thickness of the 1 st outer layer portion 101 and the 2 nd outer layer portion 102 of the laminate 10 is not particularly limited, and may be 0.2 μm or more and 40 μm or less, and preferably 0.5 μm or more and 20 μm or less.

The external electrode layers 40 include a 1 st external electrode layer 41 and a 2 nd external electrode layer 42.

The 1 st external electrode layer 41 is disposed on the 1 st end surface LS1 of the laminate 10 and connected to the 1 st internal electrode layer 31. The 1 st outer electrode layer 41 may extend from the 1 st end surface LS1 to a part of the 1 st main surface TS1 and a part of the 2 nd main surface TS 2. The 1 st external electrode layer 41 may extend from the 1 st end surface LS1 to a portion of the 1 st side surface WS1 and a portion of the 2 nd side surface WS 2. That is, the 1 st external electrode layer 41 may have the 1 st extension electrode portion 41TS extending from the 1 st end surface LS1 to a portion of the 1 st main surface TS1, a portion of the 2 nd main surface TS2, a portion of the 1 st side surface WS1, and a portion of the 2 nd side surface WS 2.

The 2 nd external electrode layer 42 is disposed on the 2 nd end surface LS2 of the laminate 10 and connected to the 2 nd internal electrode layer 32. The 2 nd outer electrode layer 42 may also extend from the 2 nd end surface LS2 to a part of the 1 st main surface TS1 and a part of the 2 nd main surface TS 2. In addition, the 2 nd external electrode layer 42 may extend from the 2 nd end surface LS2 to a portion of the 1 st side surface WS1 and a portion of the 2 nd side surface WS 2. That is, the 2 nd external electrode layer 42 may have the 2 nd extension electrode portion 42TS extending from the 2 nd end surface LS2 to a portion of the 1 st main surface TS1, a portion of the 2 nd main surface TS2, a portion of the 1 st side surface WS1, and a portion of the 2 nd side surface WS 2.

The 1 st external electrode layer 41 has a 1 st base electrode layer 415 and a 1 st plating layer 416, and the 2 nd external electrode layer 42 has a 2 nd base electrode layer 425 and a 2 nd plating layer 426.

The 1 st base electrode layer 415 and the 2 nd base electrode layer 425 are fired layers containing metal and glass. The glass may be a glass component containing at least one selected from B, Si, Ba, Mg, Al, Li, and the like. As a specific example, borosilicate glass can be used. The metal contains Cu as a main component. The metal may contain at least one selected from metals such as Ni, Ag, Pd, and Au, or alloys such as Ag — Pd alloys as a main component, or may contain at least one selected from metals such as Ni, Ag, Pd, and Au, or alloys such as Ag — Pd alloys as a component other than the main component.

The fired layer is a layer obtained by applying a conductive paste containing metal and glass to a laminate by a dipping method and firing the paste. The internal electrode layers may be fired after firing, or may be fired simultaneously with the firing of the internal electrode layers. The fired layer may be a plurality of layers.

The 1 st base electrode layer 415 has a 1 st inner electrode portion 410 adjacent to the inner layer portion 100 of the laminate 10, a 1 st outer electrode portion 411 adjacent to the 1 st outer layer portion 101 of the laminate 10, and a 1 st outer electrode portion 412 adjacent to the 2 nd outer layer portion 102 of the laminate 10.

The 2 nd base electrode layer 425 has a 2 nd inner layer electrode portion 420 adjacent to the inner layer portion 100 of the laminate 10, a 2 nd outer layer electrode portion 421 adjacent to the 1 st outer layer portion 101 of the laminate 10, and a 2 nd outer layer electrode portion 422 adjacent to the 2 nd outer layer portion 102 of the laminate 10.

In the 1 st underlying electrode layer 415 formed by the dipping method, the thickness of each of the 1 st outer electrode portions 411 and 412 is thinner than the thickness of the 1 st inner electrode portion 410. In addition, in the 2 nd base electrode layer 425 formed using the dipping method, the thickness of each of the 2 nd outer electrode portions 421 and 422 is thinner than the thickness of the 2 nd inner electrode portion 420. The thickness of the 1 st inner electrode portion 410, the thickness of the 1 st outer electrode portions 411 and 412, the thickness of the 2 nd inner electrode portion 420, and the thickness of the 2 nd outer electrode portions 421 and 422 are the thicknesses in the longitudinal direction L of the laminate 10.

In the present embodiment, the maximum thickness of each of the 1 st inner electrode portion 410 and the 2 nd inner electrode portion 420 is 1 μm or more and 40 μm or less, preferably 3 μm or more and 35 μm or less, and more preferably 5 μm or more and 25 μm or less by making the thickness thinner.

The 1 st outer layer electrode portion 411 includes a 1 st outer layer high content region 411H and a 1 st outer layer low content region 411L in this order from the 1 st end face LS1 of the laminate 10. The 1 st outer layer electrode portion 412 includes a 1 st outer layer high content region 412H and a 1 st outer layer low content region 412L in this order from the 1 st end face LS1 of the laminate 10. The 1 st inner electrode portion 410 includes a 1 st inner high content region 410H and a 1 st inner low content region 410L in this order from the 1 st end face LS1 of the laminate 10.

The 2 nd outer layer electrode portion 421 has a 2 nd outer layer high content region 421H and a 2 nd outer layer low content region 421L in this order from the 2 nd end face LS2 of the laminate 10. The 2 nd outer layer electrode portion 422 includes a 2 nd outer layer high content region 422H and a 2 nd outer layer low content region 422L in this order from the 2 nd end face LS2 of the laminate 10. The 2 nd inner electrode portion 420 has a 2 nd inner high content region 420H and a 2 nd inner low content region 420L in this order from the 2 nd end face LS2 of the laminate 10.

The 1 st outer layer high content region 411H contains the same metal component Ni as the metal component Ni contained in the metal film 50M in the 1 st metal diffusion base 511, and the 1 st outer layer low content region 411L does not contain the metal component Ni. Thus, the content of metal Ni in the 1 st outer layer high-content region 411H is higher than the content of metal Ni in the 1 st outer layer low-content region 411L. On the other hand, the content of metallic Cu in the 1 st outer layer high content region 411H is substantially the same as the content of metallic Cu in the 1 st outer layer low content region 411L. As described above, the content of the metal in the 1 st outer layer high content region 411H is higher than the content of the metal in the 1 st outer layer low content region 411L in accordance with the high content of the metal Ni. In addition, the content of glass in the 1 st outer layer high content region 411H is lower than the content of glass in the 1 st outer layer low content region 411L.

Similarly, the 1 st outer layer high content region 412H contains the same metal component Ni as the metal component Ni contained in the metal film 50M in the 1 st metal diffusion base 512, and the 1 st outer layer low content region 412L does not contain the metal component Ni. Thus, the content of metal Ni in the 1 st outer layer high content region 412H is higher than the content of metal Ni in the 1 st outer layer low content region 412L. On the other hand, the content of metallic Cu in the 1 st outer layer high content region 412H is substantially the same as the content of metallic Cu in the 1 st outer layer low content region 412L. As described above, the content of the metal in the 1 st outer layer high content region 412H is higher than the content of the metal in the 1 st outer layer low content region 412L in accordance with the high content of the metal Ni. The content of glass in the 1 st outer layer high content region 412H is lower than the content of glass in the 1 st outer layer low content region 412L.

Similarly, the 2 nd outer layer high content region 421H contains the same metal component Ni as the metal component Ni contained in the metal film 50M in the 2 nd metal diffusion base 521, and the 2 nd outer layer low content region 421L does not contain the metal component Ni. Thus, the content of metal Ni in the 2 nd outer layer high content region 421H is higher than the content of metal Ni in the 2 nd outer layer low content region 421L. On the other hand, the content of metallic Cu in the 2 nd outer layer high content region 421H is substantially the same as the content of metallic Cu in the 2 nd outer layer low content region 421L. As described above, the content of the metal in the 2 nd outer layer high content region 421H is higher than the content of the metal in the 2 nd outer layer low content region 421L in accordance with the high content of the metal Ni. In addition, the content of glass in the 2 nd outer layer high content region 421H is lower than the content of glass in the 2 nd outer layer low content region 421L.

Similarly, the 2 nd outer layer high content region 422H contains the same metal component Ni as the metal component Ni contained in the metal film 50M in the 2 nd metal diffusion base 522, and the 2 nd outer layer low content region 422L does not contain the metal component Ni. Thus, the content of metal Ni in the 2 nd outer layer high content region 422H is higher than the content of metal Ni in the 2 nd outer layer low content region 422L. On the other hand, the content of metallic Cu in the 2 nd outer layer high content region 422H is substantially the same as the content of metallic Cu in the 2 nd outer layer low content region 422L. As described above, the content of the metal in the 2 nd outer layer high content region 422H is higher than the content of the metal in the 2 nd outer layer low content region 422L in accordance with the high content of the metal Ni. The content of glass in the 2 nd outer layer high content region 422H is lower than the content of glass in the 2 nd outer layer low content region 422L.

The 1 st inner-layer high-content region 410H contains the same metal component Ni as the metal component Ni contained in the 1 st inner electrode layer 31, and the 1 st inner-layer low-content region 410L does not contain the metal component Ni. Thus, the content of metal Ni in the 1 st inner-layer high-content region 410H is higher than the content of metal Ni in the 1 st inner-layer low-content region 410L. On the other hand, the content of metallic Cu in the 1 st inner high content region 410H is substantially the same as the content of metallic Cu in the 1 st inner low content region 410L. As described above, the content of the metal in the 1 st inner high content region 410H is higher than the content of the metal in the 1 st inner low content region 410L in accordance with the high content of the metal Ni. The content of glass in the 1 st inner layer high content region 410H is lower than the content of glass in the 1 st inner layer low content region 410L.

The 2 nd inner-layer high-content region 420H contains the same metal component Ni as the metal component Ni contained in the 2 nd inner electrode layer 32, and the 2 nd inner-layer low-content region 420L does not contain the metal component Ni. Thus, the content of metal Ni in the 2 nd inner layer high content region 420H is higher than the content of metal Ni in the 2 nd inner layer low content region 420L. On the other hand, the content of metallic Cu in the 2 nd inner layer high content region 420H is substantially the same as the content of metallic Cu in the 2 nd inner layer low content region 420L. In this way, the content of the metal in the 2 nd inner layer high content region 420H is higher than the content of the metal in the 2 nd inner layer low content region 420L in accordance with the high content of the metal Ni. The content of glass in the 2 nd inner high content region 420H is lower than the content of glass in the 2 nd inner low content region 420L.

The 1 st outer high content region 411H, the 1 st inner high content region 410H, and the 1 st outer high content region 412H are connected. Similarly, the 2 nd outer layer high content region 421H, the 2 nd inner layer high content region 420H, and the 2 nd outer layer high content region 422H are connected.

The thickness of each of the 1 st outer layer high content region 411H, the 1 st inner layer high content region 410H, and the 1 st outer layer high content region 412H is not particularly limited, and may be, for example, 0.5 μm or more and 4 μm or less. Similarly, the thicknesses of the 2 nd outer layer high content region 421H, the 2 nd inner layer high content region 420H, and the 2 nd outer layer high content region 422H are not particularly limited, and may be, for example, 0.5 μm or more and 4 μm or less.

The 1 st outer-layer high-content region 411H may be present so as to be offset to a part of the 1 st outer-layer electrode portion 411 in the stacking direction T, for example, so as to be offset to the 1 st inner-layer electrode portion 410 side. In this case, the 1 st metal diffusion base 511, that is, the metal film 50M is present toward a part of the 1 st outer layer section 101 of the laminate 10 in the lamination direction T, for example, toward the inner layer section 100 side.

Similarly, the 1 st outer layer high content region 412H may be present so as to be offset to a part of the 1 st outer layer electrode portion 412 in the stacking direction T, for example, may be present so as to be offset to the 1 st inner layer electrode portion 410 side. In this case, the 1 st metal diffusion base 512, that is, the metal film 50M is present biased to a part in the lamination direction T of the 2 nd outer layer section 102 of the laminate 10, for example, biased to the inner layer section 100 side.

Similarly, the 2 nd outer layer high content region 421H may be present so as to be offset to a part of the 2 nd outer layer electrode portion 421 in the stacking direction T, for example, may be present so as to be offset to the 2 nd inner layer electrode portion 420 side. In this case, the 2 nd metal diffusion base 521, that is, the metal film 50M is present biased to a part of the 1 st outer layer section 101 of the laminate 10 in the lamination direction T, for example, biased to the inner layer section 100 side.

Similarly, the 2 nd outer layer high content region 422H may be present so as to be biased toward a part of the 2 nd outer layer electrode portion 422 in the stacking direction T, for example, toward the 2 nd inner layer electrode portion 420 side. In this case, the 2 nd metal diffusion base 522, that is, the metal film 50M is present biased to a part in the lamination direction T of the 2 nd outer layer section 102 of the laminate 10, for example, biased to the inner layer section 100 side.

Alternatively, the 1 st outer-layer high-content region 411H may be arranged over the entire 1 st outer-layer electrode portion 411 in the stacking direction T. In this case, the 1 st metal diffusion base 511, that is, the metal film 50M is disposed on the entire portion of the 1 st outer layer section 101 of the laminate 10 in the lamination direction T, for example, from a portion in contact with the boundary between the 1 st outer layer section 101 and the inner layer section 100 to a portion in contact with the 1 st main surface TS 1. In other words, the 1 st metal diffusion base 511, that is, the metal film 50M is disposed to the ridge line portion of the laminate 10.

Similarly, the 1 st outer layer high content region 412H may be disposed in the entire 1 st outer layer electrode portion 412 in the stacking direction T. In this case, the 1 st metal diffusion base 512, that is, the metal film 50M is disposed over the entire portion in the lamination direction T of the 2 nd outer layer section 102 of the laminate 10, for example, over the entire portion from the portion in contact with the boundary between the 2 nd outer layer section 102 and the inner layer section 100 to the portion in contact with the 2 nd main surface TS 2. In other words, the 1 st metal diffusion base 512, i.e., the metal film 50M is disposed to the ridge line portion of the laminate 10.

Similarly, the 2 nd outer-layer high-content region 421H may be disposed on the entire 2 nd outer-layer electrode portion 421 in the stacking direction T. In this case, the 2 nd metal diffusion base 521, that is, the metal film 50M is disposed on the entire portion of the 1 st outer layer portion 101 of the laminate 10 in the lamination direction T, for example, from a portion in contact with the boundary between the 1 st outer layer portion 101 and the inner layer portion 100 to a portion in contact with the 1 st main surface TS 1. In other words, the 2 nd metal diffusion base 521, i.e., the metal film 50M is disposed to the ridge line portion of the laminate 10.

Similarly, the 2 nd outer layer high content region 422H may be disposed on the entire 2 nd outer layer electrode portion 422 in the stacking direction T. In this case, the 2 nd metal diffusion base 522, that is, the metal film 50M is disposed over the entire portion of the laminate 10 in the lamination direction T of the 2 nd outer layer section 102, for example, from a portion in contact with the boundary between the 2 nd outer layer section 102 and the inner layer section 100 to a portion in contact with the 2 nd main surface TS 2. In other words, the 2 nd metal diffusion base 522, that is, the metal film 50M is disposed to the ridge line portion of the laminate 10.

The 1 st plating layer 416 covers at least a portion of the 1 st base electrode layer 415, and the 2 nd plating layer 426 covers at least a portion of the 2 nd base electrode layer 425. The 1 st plating layer 416 and the 2 nd plating layer 426 include at least one selected from metals such as Cu, Ni, Ag, Pd, and Au, and alloys such as Ag — Pd alloys, for example.

The 1 st plating layer 416 and the 2 nd plating layer 426 may be formed of a plurality of layers. The two-layer structure of the Ni plating layer and the Sn plating layer is preferable. The Ni plating layer can prevent the base electrode layer from being corroded by solder when the ceramic electronic component is mounted, and the Sn plating layer can improve the wettability of solder when the ceramic electronic component is mounted, thereby facilitating mounting.

The thickness of each of the 1 st plating layer 416 and the 2 nd plating layer 426 is not particularly limited, and may be 1 μm or more and 10 μm or less.

The measurement of the metal content can be confirmed by X-ray diffraction (XRD) or wavelength dispersive X-ray analysis (WDX). When the content of metal is measured by WDX, the multilayer ceramic capacitor of the measurement sample is exposed at its cross section by polishing or the like. The exposed cross section is analyzed by WDX for the portion to be measured, and the distribution state of the element to be measured is measured. From the measurement results, a mapping analysis result of the element to be measured can be obtained. The content of the glass can be determined by performing WDX mapping analysis on the elements constituting the glass in the same manner as described above.

The metal content can be measured by measuring the area of a region occupied by the metal in a region divided by a unit area in the cross section. The content of the glass can be measured by measuring the area of the region occupied by the glass in the region divided by the unit area in the cross section. The unit area is a square area. The length of one side of the square is, for example, 0.5 μm or more and 4 μm or less.

Next, a method for manufacturing the multilayer ceramic capacitor 1 will be described. First, a dielectric sheet for the dielectric layer 20, a conductive paste for the internal electrode layer 30, and a conductive paste for the metal film 50M are prepared. The dielectric sheet and the conductive paste contain a binder and a solvent. As the binder and the solvent, known materials can be used.

Next, a conductive paste is printed on the dielectric sheet, for example, in a predetermined pattern, thereby forming an internal electrode pattern on the dielectric sheet. Further, a metal film pattern is formed on the dielectric sheet by printing a conductive paste on the dielectric sheet, for example, in a predetermined pattern. As a method for forming the internal electrode pattern and the metal film pattern, screen printing, gravure printing, or the like can be used.

Next, the dielectric sheet for the 2 nd outer layer part 102 on which the metal film pattern is printed, and the dielectric sheets for the 2 nd outer layer part 102 on which the internal electrode pattern and the metal film pattern are not printed are stacked by a predetermined number. Dielectric sheets for the inner layer portion 100 on which the inner electrode patterns are printed are sequentially laminated. A predetermined number of dielectric sheets for the 1 st outer layer part 101 on which the metal film pattern is printed, and a predetermined number of dielectric sheets for the 1 st outer layer part 101 on which the internal electrode pattern and the metal film pattern are not printed are stacked. Thus, a laminated sheet was produced.

Next, the laminated sheet is pressed in the laminating direction by an isostatic pressing method or the like to produce a laminated block. Next, the laminated block is cut into a predetermined size, and the laminated chips are cut out. At this time, the corners and the ridge portions of the laminated chips are rounded by barrel polishing or the like. Next, the laminated chip is fired to produce the laminated body 10. The firing temperature depends on the materials of the dielectric and the internal electrode, but is preferably 900 ℃ to 1400 ℃.

Next, the 1 st end surface LS1 of the laminate 10 was immersed in a conductive paste as an electrode material for the base electrode layer by an immersion method, and the conductive paste for the 1 st base electrode layer 415 was applied to the 1 st end surface LS 1. Similarly, the 2 nd end surface LS2 of the laminate 10 is immersed in a conductive paste as an electrode material for the base electrode layer by an immersion method, and the conductive paste for the 2 nd base electrode layer 425 is applied to the 2 nd end surface LS 2. Then, these conductive pastes are fired to form a 1 st underlying electrode layer 415 and a 2 nd underlying electrode layer 425 as fired layers. The firing temperature is preferably 600 ℃ to 900 ℃.

Then, a 1 st plating layer 416 is formed on the surface of the 1 st base electrode layer 415 to form a 1 st external electrode layer 41, and a 2 nd plating layer 426 is formed on the surface of the 2 nd base electrode layer 425 to form a 2 nd external electrode layer 42. Through the above steps, the multilayer ceramic capacitor 1 described above can be obtained.

Here, the inventors (or the inventors) of the present application have studied thinning of the 1 st external electrode layer 41 and the 2 nd external electrode layer 42, and particularly, thinning of the 1 st base electrode layer 415 and the 2 nd base electrode layer 425, from the viewpoint of downsizing of the multilayer ceramic capacitor 1. For example, as described above, the maximum thickness of the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425 is 1 μm or more and 40 μm or less, preferably 3 μm or more and 35 μm or less, and more preferably 5 μm or more and 25 μm or less. However, the inventors (or the inventors) of the present application have found that when the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425 are made thin, the water resistance of the laminated ceramic capacitor is lowered. This is considered to be due to the following reason.

When the 1 st base electrode layer 415 and the 2 nd base electrode layer 425 are formed by the dipping method, when the 1 st end surface LS1 and the 2 nd end surface LS2 of the laminate 10 are dipped in the electrode material, the thickness of the 1 st base electrode layer 415 at the ridge line portion of the 1 st end surface LS1 of the laminate 10 becomes thinner than the thickness of the 1 st base electrode layer 415 at the center portion of the 1 st end surface LS1 of the laminate 10 due to the surface tension of the paste-like electrode material. Further, the thickness of the 1 st base electrode layer 415 at the ridge portion of the 2 nd end surface LS2 of the stacked body 10 becomes thinner than the thickness of the 1 st base electrode layer 415 at the central portion of the 2 nd end surface LS2 of the stacked body 10. In other words, as described above, in the 1 st underlying electrode layer 415, the thickness of the 1 st outer electrode portions 411 and 412 becomes thinner than the thickness of the 1 st inner electrode portion 410. In addition, in the 2 nd base electrode layer 425, the thickness of the 2 nd outer electrode portions 421 and 422 becomes thinner than the thickness of the 2 nd inner electrode portion 420.

Further, when the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425 are formed by an immersion method using a paste-like electrode material of a metal such as Cu and glass, variation in grain growth of the metal such as Cu may occur during firing, and a portion having a low metal content may occur.

Therefore, it is considered that, when the 1 st underlying electrode layer 415 is made thin, moisture enters through the portions having a low metal content in the ridge line portions of the 1 st end surface LS1 of the laminate 10 in the 1 st underlying electrode layer 415, that is, in the 1 st outer layer electrode portions 411 and 412 of the 1 st underlying electrode layer 415. Further, it is considered that when the thickness of the 2 nd base electrode layer 425 is reduced, moisture enters through the portions having a low metal content in the ridge line portions of the 2 nd end surface LS2 of the laminate 10 in the 2 nd base electrode layer 425, that is, in the 2 nd outer layer electrode portions 421 and 422 of the 2 nd base electrode layer 425.

For example, when forming the plating layer, it is considered that the plating solution enters the laminate 10 from the ridge portion of the 1 st end surface LS1 of the laminate 10, that is, the 1 st base electrode layer 415 having a low metal content in the 1 st outer electrode portion 411 and 412. Further, it is considered that the plating solution enters the laminated body 10 from the end of the 1 st extension electrode portion 41TS in the 1 st base electrode layer 415. Similarly, when forming the plating layer, it is considered that the plating solution enters the laminate 10 from the ridge portion of the 2 nd end surface LS2 of the laminate 10, that is, the 2 nd base electrode layer 425 having a low metal content in the 2 nd outer electrode layer sections 421 and 422. Further, it is considered that the plating solution enters the stacked body 10 from the end of the 2 nd extension electrode portion 42TS in the 2 nd base electrode layer 425. In the present application, moisture is a concept including a plating solution, and water resistance is a concept including resistance to the plating solution.

Alternatively, when the 1 st underlying electrode layer 415 is thin at the ridge line portion of the 1 st end surface LS1 of the laminate 10, that is, at the 1 st outer electrode portion 411 and 412, the 1 st plating layer 416 may not be formed at the ridge line portion of the 1 st end surface LS1 of the laminate 10, that is, at the 1 st outer electrode portion 411 and 412. In this case, even after the plating layers are formed, moisture in the atmosphere may infiltrate into the laminate 10 from the ridge portion of the 1 st end surface LS1 of the laminate 10 where the 1 st plating layer 416 is not formed, that is, the 1 st underlying electrode layer 415 in the 1 st outer electrode layer portions 411 and 412. Similarly, when the ridge portions of the 2 nd end surface LS2 of the laminate 10, that is, the 2 nd base electrode layer 425 in the 2 nd outer electrode layer portions 421 and 422 are thin, the 2 nd plating layer 426 may not be formed in the ridge portions of the 2 nd end surface LS2 of the laminate 10, that is, the 2 nd outer electrode layer portions 421 and 422. In this case, even after the plating layer is formed, moisture in the atmosphere may infiltrate into the laminate 10 from the ridge portions of the 2 nd end surface LS2 of the laminate 10 where the 2 nd plating layer 426 is not formed, that is, the 2 nd base electrode layer 425 in the 2 nd outer electrode layer portions 421 and 422.

It is considered that, when the moisture thus impregnated enters the inner layer portion 100 of the laminate 10, that is, the inner conductor layer, the electrical characteristics of the capacitor are degraded.

In this regard, in the present embodiment, when the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425 are fired, solid-phase interdiffusion occurs between the metal Ni of the metal film 50M in the 1 st metal diffusion base 511 and the metal Cu in the 1 st outer layer high content region 411H, whereby a Ni — Cu alloy is formed in the 1 st outer layer high content region 411H, and strong bonding can be secured between the two. Similarly, solid-phase interdiffusion occurs between the metal Ni of the metal film 50M in the 1 st metal diffusion base 512 and the metal Cu in the 1 st outer layer high content region 412H, whereby a Ni — Cu alloy is formed in the 1 st outer layer high content region 412H, and strong bonding can be secured between the two.

Similarly, solid-phase interdiffusion occurs between the metal Ni of the metal film 50M in the 2 nd metal diffusion base 521 and the metal Cu in the 2 nd outer layer high content region 421H, so that an Ni — Cu alloy is formed in the 2 nd outer layer high content region 421H, and strong bonding can be secured between the two. Similarly, solid-phase interdiffusion occurs between the metal Ni of the metal film 50M in the 2 nd metal diffusion base 522 and the metal Cu in the 2 nd outer layer high content region 422H, so that a Ni — Cu alloy is formed in the 2 nd outer layer high content region 422H, and strong bonding can be secured between the two.

Specifically, the base electrode layer contains glass frit for the purpose of improving the adhesion between the base electrode layer and the laminate, preventing the immersion of a plating solution, and the like. As the glass powder, borate glass, borosilicate glass, and aluminate glass have been widely used. As the modifying element, zinc oxide, alkaline earth metal oxide, or the like is used for the glass frit. When the base electrode layer is fired, the glass softens and flows at the base electrode layer/metal film interface. Ni of the metal film dissolves and diffuses into the glass that has become a liquid phase, and further precipitates on the external electrode layer Cu and diffuses into the inside.

For the same reason, when the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425 are fired, the metal Ni of the 1 st internal electrode layer 31 and the metal Cu of the 1 st internal layer high content region 410H are subjected to solid phase interdiffusion, so that an Ni — Cu alloy is formed in the 1 st internal layer high content region 410H, and a strong bond is secured between the two. Similarly, solid-phase interdiffusion occurs between the metal Ni of the 2 nd internal electrode layer 32 and the metal Cu of the 2 nd inner-layer high-content region 420H, so that an Ni — Cu alloy is formed in the 2 nd inner-layer high-content region 420H, and strong bonding can be secured between the two.

As a result, as shown in fig. 4 and 5, the metal content in the 1 st outer layer high content regions 411H and 412H and the 2 nd outer layer high content regions 421H and 422H increases during firing of the 1 st underlying electrode layer 415 and the 2 nd underlying electrode layer 425. In the 1 st inner layer high content region 410H and the 2 nd inner layer high content region 420H, the metal content ratio is high.

Fig. 4 is an enlarged cross-sectional view of a portion a corresponding to the cross-section of the multilayer ceramic capacitor shown in fig. 2, which is an example of actual observation, after firing of the base electrode layer of the external electrode layer and before forming the plating layer. Fig. 5 is an enlarged cross-sectional view of a portion a of the cross-section of the multilayer ceramic capacitor shown in fig. 2, which corresponds to the portion a of the external electrode layer after firing the base electrode layer and before forming the plating layer, and is another example of actual observation. In fig. 4, the 2 nd metal diffusion base 521, that is, the metal film 50M is present toward the inner layer 100 of the 1 st outer layer portion 101, and the 2 nd outer layer high content region 421H is present toward the 2 nd inner layer electrode portion 420 of the 2 nd outer layer electrode portion 421. In fig. 5, the 2 nd metal diffusion base 521, that is, the metal film 50M is disposed on the entire 1 st outer layer section 101 in the stacking direction T, and the 2 nd outer layer high content region 421H is disposed on the entire 2 nd outer layer electrode section 421 in the stacking direction T.

As described above, according to the multilayer ceramic capacitor 1 of the present embodiment, the content ratio of the metal in the 1 st outer layer high content regions 411H and 412H of the 1 st base electrode layer 415 of the 1 st external electrode layer 41 is relatively high, and the content ratio of the metal in the 2 nd outer layer high content regions 421H and 422H of the 2 nd base electrode layer 425 of the 2 nd external electrode layer 42 is relatively high. Accordingly, even if the 1 st underlying electrode layer 415 of the 1 st external electrode layer 41 is thinned, the penetration of moisture into the relatively thin 1 st outer layer electrode portions 411 and 412 can be suppressed. Even if the 2 nd base electrode layer 425 in the 2 nd external electrode layer 42 is thinned, the penetration of moisture into the relatively thin 2 nd outer layer electrode portions 421 and 422 can be suppressed. Therefore, in the multilayer ceramic capacitor 1 including the external electrode layer including the base electrode layer as a fired layer, even if the base electrode layer in the external electrode layer is thinned, it is possible to suppress a decrease in water resistance of the base electrode layer of the external electrode layer. As a result, the deterioration of the electrical characteristics of the capacitor can be suppressed.

In the multilayer ceramic capacitor 1 of the present embodiment, the content ratio of the metal in the 1 st inner layer high content region 410H of the 1 st base electrode layer 415 of the 1 st external electrode layer 41 is relatively high, and the content ratio of the metal in the 2 nd inner layer high content region 420H of the 2 nd base electrode layer 425 of the 2 nd external electrode layer 42 is relatively high. In addition, in the 1 st base electrode layer 415 in the 1 st external electrode layer 41, the 1 st outer layer high content region 411H, the 1 st inner layer high content region 410H, and the 1 st outer layer high content region 412H are connected, and in the 2 nd base electrode layer 425 in the 2 nd external electrode layer 42, the 2 nd outer layer high content region 421H, the 2 nd inner layer high content region 420H, and the 2 nd outer layer high content region 422H are connected. This can further suppress the penetration of moisture into the inner layer portion 100, i.e., the inner conductor layer, of the laminate 10.

In the multilayer ceramic capacitor 1 of the present embodiment, the 1 st outer-layer high-content regions 411H and 412H may be present so as to be offset to at least a portion on the 1 st inner electrode portion 410 side in the stacking direction T, and the 2 nd outer-layer high-content regions 421H and 422H may be present so as to be offset to at least a portion on the 2 nd inner electrode portion 420 side in the stacking direction T. This can provide an effect of suppressing the penetration of moisture into the inner layer portion 100, i.e., the inner conductor layer, of the laminate 10.

In the laminated ceramic capacitor 1 of the present embodiment, the 1 st outer-layer high-content region 411H may be disposed over the entire 1 st outer-layer electrode portion 411 in the lamination direction T, that is, over the entire portion from the portion in contact with the boundary between the 1 st outer layer portion 101 and the inner layer portion 100 to the portion in contact with the 1 st main surface TS 1. Similarly, the 1 st outer layer high content region 412H may be disposed over the entire 1 st outer layer electrode portion 412 in the stacking direction T, that is, over the entire region from the portion in contact with the boundary between the 2 nd outer layer portion 102 and the inner layer portion 100 to the portion in contact with the 2 nd main surface TS 2. Similarly, the 2 nd outer layer high content region 421H may be disposed over the entire 2 nd outer layer electrode portion 421 in the stacking direction T, that is, over the entire region from the portion in contact with the boundary between the 1 st outer layer portion 101 and the inner layer portion 100 to the portion in contact with the 1 st main surface TS 1. Similarly, the 2 nd outer layer high content region 422H may be disposed over the entire 2 nd outer layer electrode portion 422 in the stacking direction T, that is, over the entire region from the portion in contact with the boundary between the 2 nd outer layer portion 102 and the inner layer portion 100 to the portion in contact with the 2 nd main surface TS 2. This can further suppress the penetration of moisture into the inner layer portion 100 of the laminate 10, i.e., the inner conductor layer.

In the laminated ceramic capacitor 1 of the present embodiment, the interval between the plurality of metal films 50M in the lamination direction T in the 1 st metal diffusion bases 511 and 512 and the 2 nd metal diffusion bases 521 and 522 may be 0.2 μ M or more and 1.0 μ M or less, and preferably 0.3 μ M or more and 0.5 μ M or less. This makes it possible to obtain the 1 st outer layer high content region 411H continuous in the stacking direction T, the 1 st outer layer high content region 412H continuous in the stacking direction T, the 2 nd outer layer high content region 421H continuous in the stacking direction T, and the 2 nd outer layer high content region 422H continuous in the stacking direction T. This can provide an effect of suppressing the penetration of moisture into the inner layer portion 100, i.e., the inner conductor layer, of the laminate 10.

In the multilayer ceramic capacitor 1 of the present embodiment, the length of the metal film 50M may be equal to the length of the 1 st extension electrode portion 41TS in the 1 st base electrode layer 415 of the 1 st external electrode layer 41 and the length of the 2 nd extension electrode portion 42TS in the 2 nd base electrode layer 425 of the 2 nd external electrode layer 42, or may be shorter than the length of the 1 st extension electrode portion 41TS and the length of the 2 nd extension electrode portion 42 TS. The length of the metal film 50M may be as short as possible, since the metal film 50M can diffuse into the 1 st underlying electrode layer 415 of the 1 st external electrode layer 41 and the 2 nd underlying electrode layer 425 of the 2 nd external electrode layer 42 in order to form a high-content layer having a high metal content.

In the multilayer ceramic capacitor 1 of the present embodiment, the plurality of metal films 50M in the 1 st metal diffusion base 511 and 512 connected to the 1 st base electrode layer 415 of the 1 st external electrode layer 41 may be arranged so as not to overlap with the 2 nd internal electrode layer 32 in the stacking direction T of the multilayer body 10. Further, the plurality of metal films 50M in the 2 nd metal diffusion bases 521 and 522 connected to the 2 nd base electrode layer 425 of the 2 nd external electrode layer 42 may be arranged so as not to overlap with the 1 st internal electrode layer 31 in the stacking direction T of the stacked body 10. This can reduce the stray capacitance in the 1 st internal electrode layer 31 and the 2 nd internal electrode layer 32 due to the metal film 50M, and can suppress a reduction in the capacitance design of the capacitor.

In the multilayer ceramic capacitor 1 of the present embodiment, the thickness of the metal film 50M may be equal to the thickness of the internal electrode layer 30, or may be smaller than the thickness of the internal electrode layer 30. As described above, the metal film 50M may be so thin that metal diffusion into the 1 st underlying electrode layer 415 of the 1 st external electrode layer 41 and the 2 nd underlying electrode layer 425 of the 2 nd external electrode layer 42 is possible in order to form a high-content layer having a high metal content. This can suppress an increase in the material cost of the metal film 50M.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and variations can be made. For example, in the above-described embodiment, the metal diffusion base 50 having the plurality of metal films 50M stacked in the stacking direction T is exemplified. However, the feature of the present invention is not limited to this, and for example, as shown in fig. 6 and 7, the metal diffusion base 50 may be configured to have a metal film 50M extending in the stacking direction T on the end surfaces LS1 and LS 2. The shape of the metal film 50M is not particularly limited, and for example, may be substantially rectangular as shown in fig. 7.

In the above-described embodiment, the multilayer ceramic capacitor 1 in which the external electrode layers 40 are formed on the end surfaces LS1 and LS2 of the multilayer body 10 is illustrated. However, the features of the present invention are not limited to this, and the present invention can be applied to a multilayer ceramic capacitor in which external electrode layers are further formed on the side faces WS1 and WS2 of the multilayer body 10, for example. The features of the present invention are also applicable to the external electrode layers formed on the side faces WS1 and WS2 of the multilayer body 10. That is, the multilayer ceramic capacitor may further include a metal diffusion base portion for performing metal diffusion to the external electrode layers formed on the side faces WS1 and WS2 of the multilayer body 10, and the external electrode layers formed on the side faces WS1 and WS2 of the multilayer body 10 may have a high-content region with a relatively high metal content.

In the above-described embodiments, a multilayer ceramic capacitor using a dielectric ceramic is exemplified as a multilayer ceramic electronic component. However, the external electrode layer of the present invention is not limited to this, and can be applied to various laminated ceramic electronic components such as a piezoelectric component using a piezoelectric ceramic, a thermistor using a semiconductor ceramic, and an inductor using a magnetic ceramic. The piezoelectric ceramic may be a PZT-based ceramic, the semiconductor ceramic may be a spinel-based ceramic, and the magnetic ceramic may be a ferrite.