Electronic component with external electrode including sintered layer and conductive resin layer on the sintered layer

An element body of a rectangular parallelepiped shape includes a first principal surface arranged to constitute a mounting surface, a second principal surface opposing the first principal surface in a first direction, a pair of side surfaces opposing each other in a second direction, and a pair of end surfaces opposing each other in a third direction. An external electrode is disposed on the element body. The external electrode includes a conductive resin layer. The conductive resin layer continuously covers one part of the first principal surface, one part of the end surface, and one part of each of the pair of side surfaces. A length of the conductive resin layer in the first direction is smaller than a length of the conductive resin layer in the third direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic component.

2. Description of Related Art

Known electronic components include an element body of a rectangular parallelepiped shape and a plurality of external electrodes (see, for example, Japanese Unexamined Patent Publication No. H8-107038). The element body includes a first principal surface arranged to constitute a mounting surface, a second principal surface opposing the first principal surface in a first direction, a pair of side surfaces opposing each other in a second direction, and a pair of end surfaces opposing each other in a third direction. The plurality of external electrodes is disposed at both end portions of the element body in the third direction. The external electrode includes a conductive resin layer.

SUMMARY OF THE INVENTION

An object of one aspect of the present invention is to provide an electronic component that suppresses occurrence of a crack in an element body and further improves moisture resistance reliability.

An electronic component according to one aspect includes an element body of a rectangular parallelepiped shape and a plurality of external electrodes. The element body includes a first principal surface arranged to constitute a mounting surface, a second principal surface opposing the first principal surface in a first direction, a pair of side surfaces opposing each other in a second direction, and a pair of end surfaces opposing each other in a third direction. The plurality of external electrodes is disposed at both end portions of the element body in the third direction. The external electrode includes a conductive resin layer. The conductive resin layer continuously covers one part of the first principal surface, one part of the end surface, and one part of each of the pair of side surfaces. A first length of the conductive resin layer in the first direction is smaller than a second length of the conductive resin layer in the third direction.

In a case in which the electronic component is solder-mounted on an electronic device, external force applied onto the electronic component from the electronic device may act as stress on the element body. The electronic device includes, for example, a circuit board or an electronic component. The external force acts on the element body from a solder fillet formed at the solder-mounting, through the external electrode. In this case, a crack may occur in the element body. The external force tends to act on a region defined by one part of the first principal surface, one part of the end surface, and one part of the pair of side surfaces, in the element body.

In the one aspect, the conductive resin layer continuously covers the one part of the first principal surface, the one part of the end surface, and the one part of each of the pair of side surfaces. Therefore, the external force applied onto the electronic component from the electronic device tends not to act on the element body. Consequently, the one aspect suppresses occurrence of a crack in the element body.

A region between the element body and the conductive resin layer may include a path through which moisture infiltrates. In a case in which moisture infiltrates from the region between the element body and the conductive resin layer, durability of the electronic component decreases. The one aspect includes few paths through which moisture infiltrates, as compared with an electronic component in which the conductive resin layer covers the entire end surface, one part of each of the principal surfaces, and one part of each of the pair of side surfaces. Therefore, the one aspect improves moisture resistance reliability.

In the one aspect, the first length of the conductive resin layer in the first direction is smaller than the second length of the conductive resin layer in the third direction. Therefore, the one aspect includes further few paths through which moisture infiltrates, as compared with an electronic component in which the first length is equal to or larger than the second length. Therefore, the one aspect further improves the moisture resistance reliability.

In the one aspect, the external electrode may include a sintered metal layer disposed on the end portion of the element body to be positioned between the element body and the conductive resin layer. The conductive resin layer may be disposed on the sintered metal layer and on the one part of the first principal surface, and may include a portion positioned on the first principal surface. The portion positioned on the first principal surface may include a maximum thickness position. A third length from the maximum thickness position to an end edge of the conductive resin layer, in the third direction may be larger than a fourth length from the maximum thickness position to an end edge of the sintered metal layer, in the third direction. The stress acting on the element body tends to concentrate on the end edge of the sintered metal layer. In a configuration in which the third length is larger than the fourth length, volume of the portion positioned on the first principal surface is large, as compared with an electronic component in which the third length is equal to or smaller than the fourth length. Therefore, this configuration reduces the stress concentrating on the end edge of the sintered metal layer. Consequently, this configuration further suppresses the occurrence of a crack in the element body.

In the one aspect, a thickness of the portion positioned on the first principal surface may gradually decrease from the maximum thickness position to the end edge of the conductive resin layer.

In a case in which the external force acts on the end edge of the conductive resin layer, the conductive resin layer may peel off from the element body with the end edge as a starting point. In a configuration in which the thickness of the portion positioned on the first principal surface gradually decreases from the maximum thickness position to the end edge of the conductive resin layer, the external force tends not to act on the end edge of the conductive resin layer, as compared with an electronic component in which a thickness of the conductive resin layer is constant. Therefore, in this configuration, the conductive resin layer tends not to peel off from the element body.

In the one aspect, a fifth length from the end edge of the sintered metal layer to the end edge of the conductive resin layer, in the third direction may be larger than the first length of the conductive resin layer, in the first direction. In this configuration, the volume of the portion positioned on the first principal surface is large, as compared with an electronic component in which the fifth length is equal to or smaller than the first length. Therefore, this configuration reduces the stress concentrating on the end edge of the sintered metal layer. Consequently, this configuration further suppresses the occurrence of a crack in the element body.

In the one aspect, the conductive resin layer may include a portion positioned on the first principal surface and a portion positioned on the end surface. An area of the portion positioned on the first principal surface may be larger than an area of the portion positioned on the end surface. This configuration reduces the stress concentrating on the end edge of the sintered metal layer, as compared with an electronic component in which the area of the portion positioned on the first principal surface is equal to or smaller than the area of the portion positioned on the end surface. Therefore, this configuration further suppresses the occurrence of a crack in the element body.

In the one aspect, the conductive resin layer may include a portion positioned on the first principal surface and a portion positioned on the end surface. A maximum thickness of the portion positioned on the first principal surface may be larger than a maximum thickness of the portion positioned on the end surface. This configuration reduces the stress concentrating on the end edge of the sintered metal layer, as compared with an electronic component in which the maximum thickness of the portion positioned on the first principal surface is equal to or smaller than the maximum thickness of the portion positioned on the end surface. Therefore, this configuration further suppresses the occurrence of a crack in the element body.

The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same elements or elements having the same functions are denoted with the same reference numerals and overlapped explanation is omitted.

A configuration of a multilayer capacitor C1according to an embodiment will be described with reference toFIGS. 1 to 9.FIG. 1is a perspective view of the multilayer capacitor according to the embodiment.FIG. 2is a side view of the multilayer capacitor according to the embodiment.FIGS. 3 to 5are views illustrating a cross-sectional configuration of the multilayer capacitor according to the embodiment.FIG. 6is a plan view illustrating an element body, a first electrode layer, and a second electrode layer.FIG. 7is a side view illustrating the element body, the first electrode layer, and the second electrode layer.FIG. 8is an end view illustrating the element body, the first electrode layer, and the second electrode layer.FIG. 9is a view illustrating a cross-sectional configuration of the first electrode layer and the second electrode layer. In the present embodiment, an electronic component is, for example, the multilayer capacitor C1.

As illustrated inFIG. 1, the multilayer capacitor C1includes an element body3of a rectangular parallelepiped shape and a plurality of external electrodes5. In the present embodiment, the multilayer capacitor C1includes a pair of external electrodes5. The pair of external electrodes5is disposed on an outer surface of the element body3. The pair of external electrodes5is separated from each other. The rectangular parallelepiped shape includes a rectangular parallelepiped shape in which corners and ridges are chamfered, and a rectangular parallelepiped shape in which the corners and ridges are rounded.

The element body3includes a pair of principal surfaces3aand3bopposing each other, a pair of side surfaces3copposing each other, and a pair of end surfaces3eopposing each other. The pair of principal surfaces3aand3band the pair of side surfaces3chave a rectangular shape. The direction in which the pair of principal surfaces3aand3bopposes each other is a first direction D1. The direction in which the pair of side surfaces3copposes each other is a second direction D2. The direction in which the pair of end surfaces3eopposes each other is a third direction D3. The multilayer capacitor C1is solder-mounted on an electronic device. The electronic device includes, for example, a circuit board or an electronic component. The principal surface3aof the multilayer capacitor C1opposes the electronic device. The principal surface3ais arranged to constitute a mounting surface. The principal surface3ais the mounting surface.

The first direction D1is a direction orthogonal to the respective principal surfaces3aand3band is orthogonal to the second direction D2. The third direction D3is a direction parallel to the respective principal surfaces3aand3band the respective side surfaces3c,and is orthogonal to the first direction D1and the second direction D2. The second direction D2is a direction orthogonal to the respective side surfaces3c.The third direction D3is a direction orthogonal to the respective end surfaces3e.In the present embodiment, a length of the element body3in the third direction D3is larger than a length of the element body3in the first direction D1, and larger than a length of the element body3in the second direction D2. The third direction D3is a longitudinal direction of the element body3.

The pair of side surfaces3cextends in the first direction D1to couple the pair of principal surfaces3aand3b.The pair of side surfaces3calso extends in the third direction D3. The pair of end surfaces3eextends in the first direction D1to couple the pair of principal surfaces3aand3b.The pair of end surfaces3eextends in the second direction D2.

The element body3includes a pair of ridge portions3g,a pair of ridge portions3h,four ridge portions3i,a pair of ridge portions3j, and a pair of ridge portions3k.The ridge portion3gis positioned between the end surface3eand the principal surface3a.The ridge portion3his positioned between the end surface3eand the principal surface3b.The ridge portion3iis positioned between the end surface3eand the side surface3c.The ridge portion3jis positioned between the principal surface3aand the side surface3c.The ridge portion3kis positioned between the principal surface3band the side surface3c. In the present embodiment, each of the ridge portions3g,3h,3i,3j,and3kis rounded to curve. The element body3is subject to what is called a round chamfering process. Each of the ridge portions3g,3h,3i,3j, and3kincludes a curved surface having a predetermined radius of curvature. In the present embodiment, the radii of curvature of the ridge portions3g,3h,3i,3j,and3k(curved surfaces) are approximately equivalent to each other. The radii of curvature of the ridge portions3g,3h,3i,3j,and3k(curved surfaces) may be different from each other.

The end surface3eand the principal surface3aare indirectly adjacent to each other with the ridge portion3gbetween the end surface3eand the principal surface3a.The end surface3eand the principal surface3bare indirectly adjacent to each other with the ridge portion3hbetween the end surface3eand the principal surface3b.The end surface3eand the side surface3care indirectly adjacent to each other with the ridge portion3ibetween the end surface3eand the side surface3c.The principal surface3aand the side surface3care indirectly adjacent to each other with the ridge portion3jbetween the principal surface3aand the side surface3c.The principal surface3band the side surface3care indirectly adjacent to each other with the ridge portion3kbetween the principal surface3band the side surface3c.

The element body3is configured by laminating a plurality of dielectric layers in the second direction D2. The element body3includes the plurality of laminated dielectric layers. In the element body3, a lamination direction of the plurality of dielectric layers coincides with the second direction D2. Each dielectric layer includes, for example, a sintered body of a ceramic green sheet containing a dielectric material. The dielectric material includes, for example, a dielectric ceramic of BaTiO3base, Ba(Ti,Zr)O3base, or (Ba,Ca)TiO3base. In an actual element body3, each of the dielectric layers is integrated to such an extent that a boundary between the dielectric layers cannot be visually recognized. In the element body3, the lamination direction of the plurality of dielectric layers may coincide with the first direction D1.

As illustrated inFIGS. 3 to 5, the multilayer capacitor C1includes a plurality of internal electrodes7and a plurality of internal electrodes9. Each of the internal electrodes7and9is an internal conductor disposed in the element body3. Each of the internal electrodes7and9is made of a conductive material that is commonly used as an internal conductor of a multilayer electronic component. The conductive material includes, for example, a base metal. The conductive material includes, for example, Ni or Cu. Each of the internal electrodes7and9is configured as a sintered body of conductive paste containing the conductive material described above. In the present embodiment, the internal electrodes7and9are made of Ni.

The internal electrodes7and the internal electrodes9are disposed in different positions (layers) in the second direction D2. The internal electrodes7and the internal electrodes9are alternately disposed in the element body3to oppose each other in the second direction D2with an interval therebetween. Polarities of the internal electrodes7and the internal electrodes9are different from each other. In a case in which the lamination direction of the plurality of dielectric layers is the first direction D1, the internal electrodes7and the internal electrodes9are disposed in different positions (layers) in the first direction D1. Each of the internal electrodes7and9includes one end exposed to a corresponding end surface3eof the pair of end surfaces3e. The plurality of internal electrodes7and the plurality of internal electrodes9are alternately disposed in the second direction D2. The internal electrodes7and9are positioned in a plane approximately orthogonal to the principal surfaces3aand3b.The internal electrodes7and the internal electrodes9oppose each other in the second direction D2. The direction (second direction D2) in which the internal electrodes7and the internal electrodes9oppose each other is orthogonal to the direction (first direction D1) orthogonal to the principal surfaces3aand3b.

As illustrated inFIG. 2, the external electrodes5are disposed at both end portions of the element body3in the third direction D3. Each of the external electrodes5is disposed on the corresponding end surface3eside of the element body3. As illustrated inFIGS. 3 to 5, the external electrode5includes a plurality of electrode portions5a,5b,5c,and5e.The electrode portion5ais disposed on the principal surface3aand the ridge portion3g.The electrode portion5bis disposed on the ridge portion3h.The electrode portion5cis disposed on each side surface3cand each ridge portion3i.The electrode portion5eis disposed on the corresponding end surface3e.The external electrode5also includes electrode portions disposed on the ridge portion3j.

The external electrode5is formed on the four surfaces, that is, the principal surface3a,the end surface3e,and the pair of side surfaces3c,as well as on the ridge portions3g,3h,3i,and3j.The electrode portions5a,5b,5c,and5eadjacent each other are coupled and are electrically connected to each other. In the present embodiment, the external electrode5is not intentionally formed on the principal surface3b.Each electrode portion5ecovers all one ends of the corresponding internal electrodes7or9. The electrode portion5eis directly connected to the corresponding internal electrodes7or9. The external electrode5is electrically connected to the corresponding internal electrodes7or9.

As illustrated inFIGS. 3 to 5, the external electrode5includes a first electrode layer E1, a second electrode layer E2, a third electrode layer E3, and a fourth electrode layer E4. The fourth electrode layer E4is arranged to constitute the outermost layer of the external electrode5. Each of the electrode portions5a,5c,and5eincludes the first electrode layer E1, the second electrode layer E2, the third electrode layer E3, and the fourth electrode layer E4. The electrode portion5bincludes the first electrode layer E1, the third electrode layer E3, and the fourth electrode layer E4.

The first electrode layer E1included in the electrode portion5ais disposed on the ridge portion3g,and is not disposed on the principal surface3a.The first electrode layer E1included in the electrode portion5ais in contact with the entire ridge portion3g.The principal surface3ais not covered with the first electrode layer E1, and is exposed from the first electrode layer E1. The second electrode layer E2included in the electrode portion5ais disposed on the first electrode layer E1and on the principal surface3a.The first electrode layer E1included in the electrode portion5ais entirely covered with the second electrode layer E2. The second electrode layer E2included in the electrode portion5ais in contact with one part of the principal surface3aand the entire first electrode layer E1. The one part of the principal surface3ais, for example, the partial region near the end surface3e,in the principal surface3a.That is, the one part of the principal surface3ais close to the end surface3e.The electrode portion5ais four-layered on the ridge portion3g,and is three-layered on the principal surface3a.

In a case in which an element is described as being disposed on another element, the element may be directly disposed on the other element or be indirectly disposed on the other element. In a case in which an element is indirectly disposed on another element, an intervening element is present between the element and the other element. In a case in which an element is directly disposed on another element, no intervening element is present between the element and the other element.

In a case in which an element is described as covering another element, the element may directly cover the other element or indirectly cover the other element. In a case in which an element indirectly covers another element, an intervening element is present between the element and the other element. In a case in which an element directly covers another element, no intervening element is present between the element and the other element.

The second electrode layer E2included in the electrode portion5ais formed to cover the entire ridge portion3gand the one part of the principal surface3a.The one part of the principal surface3ais, for example, the partial region near the end surface3e,in the principal surface3a.That is, the one part of the principal surface3ais close to the end surface3e.The second electrode layer E2included in the electrode portion5ais formed on the first electrode layer E1and element body3in such a manner that the first electrode layer E1is positioned between the second electrode layer E2and the ridge portion3g.The second electrode layer E2included in the electrode portion5aindirectly covers the entire ridge portion3g.The second electrode layer E2included in the electrode portion5adirectly covers an entire portion of the first electrode layer E1formed on the ridge portion3g. The second electrode layer E2included in the electrode portion5adirectly covers the one part of the principal surface3a.

The first electrode layer E1included in the electrode portion5bis disposed on the ridge portion3h,and is not disposed on the principal surface3b.The first electrode layer E1included in the electrode portion5bis in contact with the entire ridge portion3h.The principal surface3bis not covered with the first electrode layer E1, and is exposed from the first electrode layer E1. The electrode portion5bdoes not include the second electrode layer E2. The principal surface3bis not covered with the second electrode layer E2, and is exposed from the second electrode layer E2. The second electrode layer E2is not formed on the principal surface3b.The electrode portion5bis three-layered.

The first electrode layer E1included in the electrode portion5cis disposed on the ridge portion3i,and is not disposed on the side surface3c.The first electrode layer E1included in the electrode portion5cis in contact with the entire ridge portion3i.The side surface3cis not covered with the first electrode layer E1, and is exposed from the first electrode layer E1. The second electrode layer E2included in the electrode portion5cis disposed on the first electrode layer E1and on the side surface3c.The second electrode layer E2included in the electrode portion5ccovers one part of the first electrode layer E1. The second electrode layer E2included in the electrode portion5cis in contact with one part of the side surface3cand the one part of the first electrode layer E1. The second electrode layer E2included in the electrode portion5cincludes a portion positioned on the side surface3c.

In a case in which an element is described as being positioned on another element, the element may be directly positioned on the other element or be indirectly positioned on the other element. In a case in which an element is indirectly positioned on another element, an intervening element is present between the element and the other element. In a case in which an element is directly positioned on another element, no intervening element is present between the element and the other element.

The second electrode layer E2included in the electrode portion5cis formed to cover one part of the ridge portion3iand one part of the side surface3c.The one part of the ridge portion3iis, for example, a partial region near the principal surface3a,in the ridge portion3i. That is, the one part of the ridge portion3iis close to the principal surface3a.The one part of the side surface3cis, for example, a corner region near the principal surface3aand end surface3e,in the side surface3c.That is, the one part of the side surface3cis close to the principal surface3aand end surface3e.The second electrode layer E2included in the electrode portion5cis formed on the first electrode layer E1and element body3in such a manner that the first electrode layer E1is positioned between the second electrode layer E2and the one part of the ridge portion3i.The second electrode layer E2included in the electrode portion5cindirectly covers the one part of the ridge portion3i.The second electrode layer E2included in the electrode portion5cdirectly covers one part of the portion of the first electrode layer E1formed on the ridge portion3i.The second electrode layer E2included in the electrode portion5cdirectly covers the one part of the side surface3c.

The electrode portion5cincludes a plurality of regions5c1and5c2. In the present embodiment, the electrode portion5cincludes only two regions5c1and5c2. The region5c2is positioned closer to the principal surface3athan the region5c1. The region5c1includes the first electrode layer E1, the third electrode layer E3, and the fourth electrode layer E4. The region5c1does not include the second electrode layer E2. The region5c1is three-layered. The region5c2includes the first electrode layer E1, the second electrode layer E2, the third electrode layer E3, and the fourth electrode layer E4. The regions5c2is four-layered on the ridge portion3i,and is three-layered on the side surface3c.The region5c1is the region where the first electrode layer E1is exposed from the second electrode layer E2. The region5c2is the region where the first electrode layer E1is covered with the second electrode layer E2.

The first electrode layer E1included in the electrode portion5eis disposed on the end surface3e.The end surface3eis entirely covered with the first electrode layer E1. The first electrode layer E1included in the electrode portion5eis in contact with the entire end surface3e.The second electrode layer E2included in the electrode portion5eis disposed on the first electrode layer E1. In the electrode portion5e,the first electrode layer E1is partially covered with the second electrode layer E2. In the electrode portion5e,the second electrode layer E2is in contact with one part of the first electrode layer E1. The second electrode layer E2included in the electrode portion5eis formed to cover one part of the end surface3e.The one part of the end surface3eis, for example, a partial region near the principal surface3a,in the end surface3e.That is, the one part of the end surface3eis close to the principal surface3a.The second electrode layer E2included in the electrode portion5eis formed on the first electrode layer E1in such a manner that the first electrode layer E1is positioned between the second electrode layer E2and the one part of the end surface3e.The second electrode layer E2included in the electrode portion5eindirectly covers the one part of the end surface3e.The second electrode layer E2included in the electrode portion5edirectly covers one part of the first electrode layer E1formed on the end surface3e.The first electrode layer E1included in the electrode portion5eis formed on the end surface3eto be coupled to the one ends of the corresponding internal electrodes7or9.

The electrode portion5eincludes a plurality of regions5e1and5e2. In the present embodiment, the electrode portion5eincludes only two regions5e1and5e2. The region5e2is positioned closer to the principal surface3athan the region5e1. The region5e1includes the first electrode layer E1, the third electrode layer E3, and the fourth electrode layer E4. The region5e1does not include the second electrode layer E2. The region5e1is three-layered. The region5e2includes the first electrode layer E1, the second electrode layer E21, the third electrode layer E3, and the fourth electrode layer E4. The regions5e2is four-layered. The region5e1is the region where the first electrode layer E1is exposed from the second electrode layer E2. The region5e2is the region where the first electrode layer E1is covered with the second electrode layer E2.

The first electrode layer E1is formed by sintering conductive paste applied onto the surface of the element body3. The first electrode layer E1is formed to cover the end surface3eand the ridge portions3g,3h,and3i.The first electrode layer E1is formed by sintering a metal component (metal powder) contained in the conductive paste. The first electrode layer E1includes a sintered metal layer. The first electrode layer E1includes a sintered metal layer formed on the element body3. The first electrode layer E1is not intentionally formed on the pair of principal surfaces3aand3band the pair of side surfaces3c.The first electrode layer E1may be unintentionally formed on the principal surfaces3aand3band the side surfaces3cdue to a production error, for example. In the present embodiment, the first electrode layer E1is a sintered metal layer made of Cu. The first electrode layer E1may be a sintered metal layer made of Ni. The first electrode layer E1contains a base metal. The conductive paste contains, for example, powder made of Cu or Ni, a glass component, an organic binder, and an organic solvent.

The second electrode layer E2is formed by curing conductive resin paste applied onto the first electrode layer E1, the principal surface3a,and the pair of side surfaces3c.The second electrode layer E2includes a conductive resin layer. The second electrode layer E2is formed over the first electrode layer E1and the element body3. In the present embodiment, the second electrode layer E2covers a partial region of the first electrode layer E1. The partial region of the first electrode layer E1is, for example, the regions corresponding to the electrode portion5a,the region5c2of the electrode portion5c,and the region5e2of the electrode portion5e,in the first electrode layer E1. The second electrode layer E2directly covers a partial region of the ridge portion3j.The partial region of the ridge portion3jis, for example, the partial region near the end surface3e,in the ridge portion3j.That is, the partial region of the ridge portion3jis close to the end surface3e.The second electrode layer E2is in contact with the partial region of the ridge portion3j.The first electrode layer E1serves as an underlying metal layer for forming the second electrode layer E2. The second electrode layer E2is a conductive resin layer formed on the first electrode layer E1.

The conductive resin paste contains, for example, a resin, a conductive material, and an organic solvent. The resin is, for example, a thermosetting resin. The conductive material includes, for example, metal powder. The metal powder includes, for example, Ag powder or Cu powder. The thermosetting resin includes, for example, a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

The third electrode layer E3is formed on the second electrode layer E2and the first electrode layer E1by plating method. The third electrode layer E3includes a plating layer. The third electrode layer E3is formed on a portion of the first electrode layer E1exposed from the second electrode layer E2. In the present embodiment, the third electrode layer E3is formed on the first electrode layer E1and the second electrode layer E2by Ni plating. The third electrode layer E3is a Ni plating layer. The third electrode layer E3may be an Sn plating layer, a Cu plating layer, or an Au plating layer. The third electrode layer E3contains Ni, Sn, Cu, or Au.

The fourth electrode layer E4is formed on the third electrode layer E3by plating method. The fourth electrode layer E4includes a plating layer. In the present embodiment, the fourth electrode layer E4is formed on the third electrode layer E3by Sn plating. The fourth electrode layer E4is an Sn plating layer. The fourth electrode layer E4may be a Cu plating layer or an Au plating layer. The fourth electrode layer E4contains Sn, Cu, or Au. The third electrode layer E3and the fourth electrode layer E4constitute a plating layer formed on the second electrode layer E2. In the present embodiment, the plating layer formed on the second electrode layer E2is two-layered.

The first electrode layer E1included in the electrode portion5a, the first electrode layer E1included in the electrode portion5b,the first electrode layer E1included in the electrode portion5c,and the first electrode layer E1included in the electrode portion5eare integrally formed. The second electrode layer E2included in the electrode portion5a,the second electrode layer E2included in the electrode portion5c,and the second electrode layer E2included in the electrode portion5eare integrally formed. The third electrode layer E3included in the electrode portion5a,the third electrode layer E3included in the electrode portion5b,the third electrode layer E3included in the electrode portion5c,and the third electrode layer E3included in the electrode portion5eare integrally formed. The fourth electrode layer E4included in the electrode portion5a,the fourth electrode layer E4included in the electrode portion5b,the fourth electrode layer E4included in the electrode portion5c,and the fourth electrode layer E4included in the electrode portion5eare integrally formed.

The first electrode layer E1(first electrode layer E1included in the electrode portion5e) is formed on the end surface3eto be connected to the corresponding internal electrodes7and9. The first electrode layer E1covers the entire end surface3e,the entire ridge portion3g,the entire ridge portion3h,and the entire ridge portion3i. The second electrode layer E2(second electrode layers E2included in the electrode portions5a,5c,and5e) continuously covers one part of the principal surface3a,one part of the end surface3e,and one part of each of the pair of side surfaces3c.The second electrode layer E2(second electrode layers E2included in the electrode portions5a,5c, and5e) covers the entire ridge portion3g,one part of the ridge portion3i,and one part of the ridge portion3j.The second electrode layer E2includes a plurality of portions each corresponding to the one part of the principal surface3a,the one part of the end surface3e,the one part of each of the pair of side surfaces3c,the entire ridge portion3g,the one part of the ridge portion3i,and the one part of the ridge portion3j. The first electrode layer E1(first electrode layer E1included in the electrode portion5e) is directly connected to the corresponding internal electrodes7and9.

The first electrode layer E1(first electrode layers E1included in the electrode portions5a,5b,5c,and5e) includes a region covered with the second electrode layer E2(second electrode layers E2included in the electrode portions5a,5c,and5e), and a region not covered with the second electrode layer E2(second electrode layers E2included in the electrode portions5a,5c,and5e). The region not covered with the second electrode layer E2is a region exposed from the second electrode layer E2. The third electrode layer E3and the fourth electrode layer E4cover the region not covered with the second electrode layer E2in the first electrode layer E1, and the second electrode layer E2.

As illustrated inFIG. 6, when viewed from the first direction D1, the first electrode layer E1(first electrode layer E1included in the electrode portion5a) is entirely covered with the second electrode layer E2. When viewed from the first direction D1, the first electrode layer E1(first electrode layer E1included in the electrode portion5a) is not exposed from the second electrode layer E2.

As illustrated inFIG. 7, when viewed from the second direction D2, a first end region near the principal surface3aof the first electrode layer E1is covered with the second electrode layer E2. The first end region of the first electrode layer E1includes the first electrode layer E1included in the region5c2. The first end region of the first electrode layer E1is close to the principal surface3a.When viewed from the second direction D2, an end edge E2e, of the second electrode layer E2crosses an end edge E1ecof the first electrode layer E1. When viewed from the second direction D2, a second end region near the principal surface3bof the first electrode layer E1is exposed from the second electrode layer E2. The second end region of the first electrode layer E1includes the first electrode layer E1included in the region5c1. The second end region of the first electrode layer E1is close to the principal surface3b.The second electrode layer E2positioned on the side surface3copposes the internal electrode7or9having polarity different from that of the second electrode layer E2, in the second direction D2.

As illustrated inFIG. 8, when viewed from the third direction D3, a third end region near the principal surface3aof the first electrode layer E1is covered with the second electrode layer E2. The third end region of the first electrode layer E1includes the first electrode layer E1included in the region5e2. The third end region of the first electrode layer E1is close to the principal surface3a.When viewed from the third direction D3, the end edge E2e1of the second electrode layer E2is positioned on the first electrode layer E1. When viewed from the third direction D3, a fourth end region near the principal surface3bof the first electrode layer E1is exposed from the second electrode layer E2. The fourth end region of the first electrode layer E1includes the first electrode layer E1included in the region5e1. The fourth end region of the first electrode layer E1is close to the principal surface3b.When viewed from the third direction D3, an area of the second electrode layer E2positioned on the end surface3eand ridge portion3gis smaller than an area of the first electrode layer E1positioned on the end surface3eand ridge portion3g.

As illustrated inFIG. 8, one end of each of the internal electrodes7and9includes a first region overlapping with the second electrode layer E2and a second region not overlapping with the second electrode layer E2, when viewed from the third direction D3. The first region is positioned closer to the principal surface3ain the first direction D1than the second region. The first electrode layer E1included in the region5e2is connected to the first region. The first electrode layer E1included in the region5e1is connected to the second region.

In the present embodiment, the second electrode layer E2continuously covers only the one part of the principal surface3a,only the one part of the end surface3e,and only the one part of each of the pair of side surfaces3c.The second electrode layer E2covers the entire ridge portion3g,only the one part of the ridge portion3i,and only the one part of the ridge portion3j.The portion of the first electrode layer E1covering the ridge portion3iis partially exposed from the second electrode layer E2. For example, the first electrode layer E1included in the region5c1is exposed from the second electrode layer E2. The first electrode layer E1is formed on the end surface3eto be connected to the first region of the corresponding internal electrode7or9. In the present embodiment, the first electrode layer E1is formed on the end surface3eto be also connected to the second region of the corresponding internal electrode7or9.

As illustrated inFIG. 2, a width of the region5c2in the third direction D3decreases with an increase in distance from the principal surface3a.The width of the region5c2in the third direction D3decreases with an increase in distance from the electrode portion5a.A width of the region5c2in the first direction D1decreases with an increase in distance from the end surface3e.The width of the region5c2in the first direction D1decreases with an increase in distance from the electrode portion5e.In the present embodiment, when viewed from the second direction D2, an end edge of the region5c2has an approximately arc shape. When viewed from the second direction D2, the region5c2has an approximately fan shape. As illustrated inFIG. 7, in the present embodiment, a width of the second electrode layer E2when viewed from the second direction D2decreases with an increase in distance from the principal surface3a.When viewed from the second direction D2, a length of the second electrode layer E2in the first direction D1decreases with an increase in distance in the third direction D3from the end surface3e.When viewed from the second direction D2, a length of the portion of the second electrode layer E2positioned on the side surface3cin the first direction D1decreases with an increase in distance in the third direction D3from an end of the element body3. As illustrated inFIG. 7, when viewed from the second direction D2, the end edge E2ecof the second electrode layer E2has an approximately arc shape.

As illustrated inFIG. 9, a length L1of the second electrode layer E2in the first direction D1is smaller than a length L2of the second electrode layer E2in the third direction D3. The length L1is, for example, defined as follows. The length L1is the maximum interval in the first direction D1between a reference plane PL1and the end edge E2e1of the second electrode layer E2that is included in the electrode portion5e(region5e2). The reference plane PL1abuts with a surface of the second electrode layer E2included in the electrode portion5a,and is parallel with the principal surface3a.The length L1is, for example, 200 to 1,200 μm. In the present embodiment, the length L1is 500 μm. The length L1may be the average value of the interval in the first direction D1between reference plane PL1and the end edge E2e1. The length L2is, for example, defined as follows. The length L2is the maximum interval in the third direction D3between a reference plane PL2and the end edge E2e2of the second electrode layer E2included in the electrode portion5a.The reference plane PL2abuts with a surface of the second electrode layer E2that is included in the electrode portion5e(region5e2), and is parallel with the end surface3e.The reference plane PL2is orthogonal to the reference plane PL1. The length L2is, for example, 400 to 1,500 μm. In the present embodiment, the length L2is 800 μm. The length L2may be the average value of the interval in the third direction D3between reference plane PL2and the end edge E2e2.

As illustrated inFIG. 9, the second electrode layer E2included in the electrode portion5ahas a maximum thickness position E2max. The maximum thickness position E2maxhas a largest thickness in the second electrode layer E2included in the electrode portion5a.In the third direction D3, the end edge E1eof the first electrode layer E1is positioned closer to the end surface3ethan the maximum thickness position E2max. The second electrode layer E2included in the electrode portion5aincludes a first portion positioned on the principal surface3a,and a second portion positioned on the ridge portion3g(the first electrode layer E1). In the present embodiment, the maximum thickness position E2maxis present in the first portion of the second electrode layer E2. In the first portion, the thickness of the second electrode layer E2included in the electrode portion5ais a thickness in the direction orthogonal to the principal surface3a.In the second portion, the thickness of the second electrode layer E2included in the electrode portion5ais a thickness in a normal direction of the ridge portion3g(curved surface).

The thickness in the first portion of the second electrode layer E2gradually decreases from the maximum thickness position E2maxto the second portion. The thickness in the first portion of the second electrode layer E2gradually decreases from the maximum thickness position E2maxto the end edge E2e2of the second electrode layer E2. The surface of the second electrode layer E2curves as the result of changes in the thickness in the second electrode layer E2of the electrode portion5a.As illustrated inFIG. 5, the thickness of the first portion of the second electrode layer E2is larger at the center in the second direction D2than at the end in the second direction D2, when viewed from the third direction D3. In the present embodiment, the thickness of the first portion of the second electrode layer E2is largest at the center in the second direction D2, and gradually decreases to the end in the second direction D2.

A thickness of the maximum thickness position E2max, that is, a maximum thickness of the second electrode layer E2included in the electrode portion5ais equal to or larger than 30 μm. In the present embodiment, the maximum thickness of the second electrode layer E2included in the electrode portion5ais 100 μm. The maximum thickness of the second electrode layer E2included in the electrode portion5ais larger than a maximum thickness of the second electrode layer E2included in the electrode portion5e(region5e2). The thickness of the second electrode layer E2included in the region5e2is a thickness in the third direction D3(direction orthogonal to the end surface3e). The second electrode layer E2included in the region5e2includes a portion positioned on the end surface3e.The maximum thickness of the second electrode layer E2included in the electrode region5e2is equal to or larger than 15 μm. In the present embodiment, the maximum thickness of the second electrode layer E2included in the electrode region5e2is 50 μm. The maximum thickness of the second electrode layer E2included in the electrode portion5ais larger than a maximum thickness of the second electrode layer E2included in the electrode portion5c(region5c2). The thickness of the second electrode layer E2included in the region5c2is a thickness in the second direction D2(direction orthogonal to the side surface3c). The second electrode layer E2included in the region5c2includes a portion positioned on the side surface3c.The maximum thickness of the second electrode layer E2included in the region5c2is equal to or larger than 5 μm. In the present embodiment, the maximum thickness of the second electrode layer E2included in the region5c2is 15 μm.

As illustrated inFIG. 9, a length L3from the maximum thickness position E2maxto the end edge E2e2of the second electrode layer E2, in the third direction D3is larger than a length L4from the maximum thickness position E2maxto the end edge E1eof the first electrode layer E1, in the third direction D3. The length L3is, for example, 200 to 800 μm. In the present embodiment, the length L3is 350 μm. The length L4is, for example, 100 to 400 μm. In the present embodiment, the length L4is 150 μm.

An area of the first portion included in the second electrode layer E2is larger than an area of the second electrode layer E2that is included in the electrode portion5e(region5e2). As described above, the first portion included in the second electrode layer E2is the portion positioned on the principal surface3a,in the second electrode layer E2included in the electrode portion5a.The second electrode layer E2included in the electrode portion5e(region5e2) is a portion positioned on the end surface3e,in the second electrode layer E2. The area of the first portion included in the second electrode layer E2is 500000 to 3750000 μm2. In the present embodiment, the area of the first portion included in the second electrode layer E2is 2000000 μm2. The area of the second electrode layer E2included in the electrode portion5e(region5e2) is 250000 to 3000000 μm2. In the present embodiment, the area of the second electrode layer E2included in the electrode portion5e(region5e2) is 1250000 μm2.

In a case in which the multilayer capacitor C1is solder-mounted on the electronic device, external force applied onto the multilayer capacitor C1from the electronic device may act as stress on the element body3. In this case, a crack may occur in the element body3. The external force acts on the element body3from a solder fillet formed at the solder-mounting, through the external electrode5. The external force tends to act on a region defined by the one part of the principal surface3a,the one part of the end surface3e,and the one part of the pair of side surfaces3c,in the element body3. In the multilayer capacitor C1, the second electrode layer E2(second electrode layer E2included in the electrode portions5a,5c,and5e) continuously covers the one part of the principal surface3a,the one part of the end surface3e,and the one part of each of the pair of side surfaces3c.Therefore, the external force applied onto the multilayer capacitor C1from the electronic device tends not to act on the element body3. Consequently, the multilayer capacitor C1suppresses occurrence of a crack in the element body3.

A region between the element body3and the second electrode layer E2may include a path through which moisture infiltrates. In a case in which moisture infiltrates from the region between the element body3and the second electrode layer E2, durability of the multilayer capacitor C1decreases. The multilayer capacitor C1includes few paths through which moisture infiltrates, as compared with an electronic component in which the second electrode layer E2covers the entire end surface3e,one part of each of the principal surfaces3aand3b,and one part of each of the pair of side surfaces3c.Therefore, the multilayer capacitor C1improves moisture resistance reliability. In the multilayer capacitor C1, the length L1of the second electrode layer E2in the first direction D1is smaller than the length L2of the second electrode layer E2in the third direction D3. Therefore, the multilayer capacitor C1includes further few paths through which moisture infiltrates, as compared with an electronic component in which the length L1is equal to or larger than the length L2. Therefore, the multilayer capacitor C1further improves the moisture resistance reliability.

The length L3, in the third direction D3, from the maximum thickness position E2maxto the end edge E2e2of the second electrode layer E2is larger than the length L4, in the third direction D3, from the maximum thickness position E2maxto the end edge E1eof the first electrode layer E1. The stress acting on the element body3tends to concentrate on the end edge E1eof the first electrode layer E1. In a configuration in which the length L3is larger than the length L4, volume of the portion positioned on the principal surface3ain the second electrode layer E2is large, as compared with an electronic component in which the length L3is equal to or smaller than the length L4. Therefore, the multilayer capacitor C1reduces the stress concentrating on the end edge E1eof the first electrode layer E1. Consequently, the multilayer capacitor C1further suppresses the occurrence of a crack in the element body3.

In a case in which the external force acts on the end edge E2e2of the second electrode layer E2, the second electrode layer E2may peel off from the element body3(principal surface3a) with the end edge E2e2as a starting point. In the multilayer capacitor C1, the thickness of the second electrode layer E2included in the electrode portion5agradually decreases from the maximum thickness position E2maxto the end edge E2e2of the second electrode layer E2. Therefore, in the multilayer capacitor C1, the external force tends not to act on the end edge E2e2of the second electrode layer E2, as compared with an electronic component in which a thickness of the second electrode layer E2is constant. Consequently, in the multilayer capacitor C1, the second electrode layer E2tends not to peel off from the element body3(principal surface3a).

In the multilayer capacitor C1, the length L5, in the third direction D3, from the end edge E1eof the first electrode layer E1to the end edge E2e2of the second electrode layer E2is larger than the length L1of the second electrode layer E2in the first direction D1. In the multilayer capacitor C1, the volume of the portion positioned on the principal surface3ain the second electrode layer E2is large, as compared with an electronic component in which the length L5is equal to or smaller than the length L1. Therefore, the multilayer capacitor C1reduces the stress concentrating on the end edge E1eof the first electrode layer E1. Consequently, the multilayer capacitor C1further suppresses the occurrence of a crack in the element body3.

In the multilayer capacitor C1, the area of the first portion included in the second electrode layer E2is larger than the area of the second electrode layer E2included in the electrode portion5e.The multilayer capacitor C1reduces the stress concentrating on the end edge E1eof the first electrode layer E1, as compared with an electronic component in which the area of the first portion included in the second electrode layer E2is equal to or smaller than the area of the second electrode layer E2included in the electrode portion5e.Therefore, the multilayer capacitor C1further suppresses the occurrence of a crack in the element body3. In an electronic component in which the area of the first portion included in the second electrode layer E2is larger than the area of the second electrode layer E2included in the electrode portion5e,bonding strength between the second electrode layer E2and the element body3is large, as compared with an electronic component in which the area of the first portion included in the second electrode layer E2is equal to or smaller than the area of the second electrode layer E2included in the electrode portion5e.Therefore, in the multilayer capacitor C1, the second electrode layer E2tends not to further peel off from the principal surface3a.

In the multilayer capacitor C1, the maximum thickness of the second electrode layer E2included in the electrode portion5ais larger than the maximum thickness of the second electrode layer E2included in the region5e2. The multilayer capacitor C1reduces the stress concentrating on the end edge E1eof the first electrode layer E1, as compared with an electronic component in which the maximum thickness of the second electrode layer E2included in the electrode portion5ais equal to or smaller than the maximum thickness of the second electrode layer E2included in the region5e2. Therefore, the multilayer capacitor C1further suppresses the occurrence of a crack in the element body3.

Next, a mounted structure of the multilayer capacitor C1will be described with reference toFIG. 10.FIG. 10is a view illustrating a mounted structure of a multilayer capacitor according to the embodiment.

As illustrated inFIG. 10, an electronic component device ECD1includes the multilayer capacitor C1and an electronic device ED. The electronic device ED includes, for example, a circuit board or an electronic component. The multilayer capacitor C1is solder-mounted on the electronic device ED. The electronic device ED includes a principal surface EDa and a plurality of pad electrodes PE1and PE2. In the present embodiment, the electronic device ED includes two pad electrodes PE1and PE2. Each of the pad electrodes PE1and PE2is disposed on the principal surface EDa. The two pad electrodes PE1and PE2are separated from each other. The multilayer capacitor C1is disposed on the electronic device ED in such a manner that the principal surface3aand the principal surface EDa oppose each other. As described above, the principal surface3ais arranged to constitute a mounting surface.

When the multilayer capacitor C1is solder-mounted, molten solder wets to the external electrodes5(fourth electrode layer E4). Solder fillets SF are formed on the external electrodes5by solidification of the wet solder. The external electrodes5and the pad electrodes PE1and PE2corresponding to each other are coupled via the solder fillets SF.

The solder fillet SF is formed on the regions5e1and5e2included in the electrode portion5e.In addition to the region5e2, the region5e1that does not include the second electrode layer E2is also coupled to the corresponding pad electrode PE1or PE2via the solder fillet SF. When viewed from the third direction D3, the solder fillet SF overlaps the region5e1included in the electrode portion5e.When viewed from the third direction D3, the solder fillet SF overlaps the first electrode layer E1included in the region5e1. Although illustration is omitted, the solder fillets SF are also formed on the regions5c1and5c2included in the electrode portion5c.A height of the solder fillet SF in the first direction D1is larger than a height of the second electrode layer E2in the first direction D1. The solder fillet SF extends in the first direction D1to be closer to the principal surface3bthan the end edge E2e1of the second electrode layer E2.

As described above, the electronic component device ECD1suppresses occurrence of a crack in the element body3, and improves moisture resistance reliability. In the electronic component device ECD1, when viewed from the third direction D3, the solder fillet SF overlaps the region5e1included in the electrode portion5e.Therefore, even in a case in which the external electrode5includes the second electrode layer E2, the electronic component device ECD1suppresses an increase in equivalent series resistance (ESR).

Although the embodiments and modifications of the present invention have been described above, the present invention is not necessarily limited to the embodiments and modifications, and the embodiment can be variously changed without departing from the scope of the invention.

The first electrode layer E1may be formed on the principal surface3ato extend over the ridge portion3gentirely or partially from the end surface3e.The first electrode layer E1may be formed on the principal surface3bto extend beyond the ridge portion3hentirely or partially from the end surface3e.In a case in which the first electrode layer E1is formed on the principal surface3b,an electrode portion disposed on the principal surface3bmay be four-layered. The first electrode layer E1may be formed on the side surface3cto extend beyond the ridge portion3ientirely or partially from the end surface3e. In a case in which the first electrode layer E1is formed on the side surface3c,an electrode portion disposed on the side surface3cmay be four-layered.

The number of internal electrodes7and9included in the multilayer capacitor C1is not limited to the number of the internal electrodes7and9illustrated. In the multilayer capacitor C1, the number of the internal electrodes connected to one external electrode5(first electrode layer E1) may be one.

In the multilayer capacitor C1, the length L1of the second electrode layer E2in the first direction D1may be equal to or larger than the length L5, in the third direction D3, from the end edge E1eof the first electrode layer E1to the end edge E2e2of the second electrode layer E2. As described above, the configuration in which the length L5is larger than the length L1reduces the stress concentrating on the end edge E1eof the first electrode layer E1, and thus further suppresses the occurrence of a crack in the element body3.

The electronic component of the present embodiment is the multilayer capacitor C1. Applicable electronic component is not limited to the multilayer capacitor. Examples of the applicable electronic components include, but not limited to, multilayer electronic components such as a multilayer inductor, a multilayer varistor, a multilayer piezoelectric actuator, a multilayer thermistor, or a multilayer composite component, and electronic components other than the multilayer electronic components.