Multilayer coil components

Abstract

To provide a multilayer coil component that is capable of suppressing the peeling of an external terminal.SOLUTION: A multilayer coil component 1F includes an element body 2 having a plurality of stacked insulator layers, a coil disposed in the element body 2, and a pair of external terminals 3 electrically connected to the coil. The element body 2 has a rectangular parallelepiped shape, and has a pair of principal surfaces 2a, 2b facing each other in a first direction D1, a pair of end surfaces 2c facing each other in a second direction D2, and a pair of side surfaces 2e facing each other in a third direction D3. The external terminals 3 in the pair are spaced from each other in the second direction D2, and embedded in the element body 2 while being spaced from the pair of end surfaces 2c and the pair of side surfaces 2e, each external terminal having an exposed surface exposing from the principal surface 2a and an inner surface 3s disposed in the element body 2. A connection surface 3t of the inner surface 3s has a recess 37 or a protrusion 38.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates to a laminated coil component. [Background technology]

[0002] Patent Document 1 describes a laminated coil component including an element body, a coil, and a pair of external electrodes. In this laminated coil component, the external electrodes are embedded in the element body so as to be exposed from the bottom surface of the element body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-113299 Summary of the Invention [Problem to be solved by the invention]

[0004] In the electronic component described above, the external electrodes may peel off from the element body.

[0005] One embodiment of the present disclosure provides a multilayer coil component capable of suppressing peeling of an external terminal. [Means for solving the problem]

[0006] A laminated coil component according to one embodiment of the present disclosure comprises an element body having a plurality of stacked insulator layers, a coil disposed within the element body, and a pair of external terminals electrically connected to the coil, wherein the element body has a rectangular parallelepiped shape and has a pair of main surfaces facing each other in a first direction, a pair of end faces facing each other in a second direction intersecting the first direction, and a pair of side surfaces facing each other in a third direction intersecting the first and second directions, and the pair of external terminals are spaced apart from each other in the second direction and are embedded in the element body at a distance from the pair of end faces and the pair of side surfaces, and each have an exposed surface exposed from one of the main surfaces and an inner surface disposed within the element body, and the inner surfaces have a concave or convex portion.

[0007] In this laminated coil component, the external terminals have inner surfaces disposed within the element body, and the inner surfaces are provided with recesses or protrusions. This increases the contact area between the element body and the external terminals, improving the adhesion of the external terminals to the element body. As a result, peeling of the external terminals can be suppressed.

[0008] The inner surface has an opposing surface facing the exposed surface and a connecting surface connecting the exposed surface and the opposing surface, and the connecting surface may have a recess or a protrusion. In this case, the recess or the protrusion is likely to catch on stress in the first direction, which makes it easy to suppress peeling of the external terminal.

[0009] The connecting surface may include a pair of first connecting surfaces facing each other in the second direction, and each of the pair of first connecting surfaces may have a recess or a protrusion. In this case, peeling of the external terminal can be suppressed more effectively than when only one of the first connecting surfaces has a recess or a protrusion.

[0010] The connecting surface may include a pair of second connecting surfaces facing each other in the third direction, and each of the pair of second connecting surfaces may have a recess or a protrusion. In this case, peeling of the external terminal can be more reliably suppressed than when only one of the second connecting surfaces has a recess or a protrusion.

[0011] When viewed from the first direction, the connection surface may have a recess adjacent to the corner of the main surface, in which case the area of ​​the element body at the corner of the main surface is increased, thereby making it possible to suppress damage to the corner of the main surface.

[0012] The connecting surface may have a recess or a protrusion extending in a direction intersecting the first direction, in which case the recess or the protrusion functions as an anchor and catches on the element body, thereby further suppressing peeling of the external terminal.

[0013] The inner surface has an opposing surface facing the exposed surface, and the opposing surface may have a recess or a protrusion. In this case, the recess or the protrusion is likely to catch on stress in the second or third direction, which makes it easier to prevent the external terminal from peeling off.

[0014] The opposing surface may have an annular recess or protrusion when viewed from the first direction. In this case, the recess or protrusion is unlikely to be formed unevenly in the second direction and the third direction relative to the opposing surface, and therefore distortion due to shrinkage during sintering is unlikely to occur.

[0015] Each of the pair of external terminals may have a plurality of stacked electrode layers. In this case, the electrode layers are stacked together with the insulating layers, thereby forming the external terminals together with the element body.

[0016] The plurality of electrode layers may be stacked so that electrode layers having different shapes are adjacent to each other when viewed from the stacking direction, which makes it easy to form recesses or protrusions on the inner surface. [Effects of the Invention]

[0017] According to one aspect of the present invention, there is provided a laminated coil component capable of suppressing peeling of external terminals. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of a laminated coil component according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the laminated coil component of FIG. [Figure 3] FIG. 3 is a bottom view of the laminated coil component of FIG. [Figure 4] FIG. 4 is a side view of the external terminal shown in FIG. [Figure 5] FIG. 5 is a bottom view of the laminated coil component according to the first modified example of the first embodiment. [Figure 6] FIG. 6 is a bottom view of a laminated coil component according to a second modified example of the first embodiment. [Figure 7]FIG. 7 is a bottom view of a laminated coil component according to a third modified example of the first embodiment. [Figure 8] FIG. 8 is a bottom view of a laminated coil component according to a fourth modified example of the first embodiment. [Figure 9] FIG. 9 is a perspective view of the laminated coil component according to the second embodiment. [Figure 10] Fig. 10(a) is a top view of the external terminal shown in Fig. 9. Fig. 10(b) is a cross-sectional view of the external terminal shown in Fig. 9. [Figure 11] 11(a) and 11(b) are a top view and a cross-sectional view of an external terminal according to a first modified example of the second embodiment, respectively. [Figure 12] Fig. 12(a) is a top view of an external terminal according to a second modified example of the second embodiment, Fig. 12(b) is a top view of an external terminal according to a third modified example of the second embodiment, and Fig. 12(c) is a top view of an external terminal according to a fourth modified example of the second embodiment. [Figure 13] FIG. 13 is a cross-sectional view of an external terminal according to a fifth modified example of the second embodiment. [Figure 14] FIG. 14 is a perspective view of the laminated coil component in accordance with the third embodiment. [Figure 15] FIG. 15 is a cross-sectional view of the external terminal shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0020] [First embodiment] As shown in Fig. 1 to Fig. 4, the laminated coil component 1 according to the first embodiment includes a rectangular parallelepiped element body 2, a pair of external terminals 3, a coil 10, and connecting conductors 26 and 27. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and ridges, and a rectangular parallelepiped shape with rounded corners and ridges. The laminated coil component 1 is, for example, a laminated high-frequency inductor. In Fig. 1, the external terminals 3 within the element body 2 are indicated by solid lines.

[0021] The element body 2 has main surfaces 2a and 2b facing each other, a pair of end surfaces 2c facing each other, and a pair of side surfaces 2e facing each other. Hereinafter, the direction in which the main surfaces 2a and 2b face each other will be referred to as a first direction D1, the direction in which the pair of end surfaces 2c face each other will be referred to as a second direction D2, and the direction in which the pair of side surfaces 2e face each other will be referred to as a third direction D3. The first direction D1, the second direction D2, and the third direction D3 intersect with each other (here, perpendicularly). In this embodiment, the first direction D1 is the height direction of the element body 2. The second direction D2 is the length direction of the element body 2. The third direction D3 is the width direction of the element body 2.

[0022] The main surfaces 2a, 2b, the pair of end surfaces 2c, and the pair of side surfaces 2e all have a rectangular shape. The long side direction of the main surfaces 2a, 2b coincides with the second direction D2. The short side direction of the main surfaces 2a, 2b coincides with the third direction D3. The main surface 2a is adjacent to each of the end surfaces 2c and each of the side surfaces 2e. The main surface 2b is adjacent to each of the end surfaces 2c and each of the side surfaces 2e. Each of the end surfaces 2c is adjacent to each of the side surfaces 2e.

[0023] The principal surfaces 2a, 2b extend in the second direction D2 to connect the pair of end surfaces 2c. The principal surfaces 2a, 2b also extend in the third direction D3 to connect the pair of side surfaces 2e. The pair of end surfaces 2c extend in the first direction D1 to connect the principal surfaces 2a, 2b. The pair of end surfaces 2c also extend in the third direction D3 to connect the pair of side surfaces 2e. The pair of side surfaces 2e extend in the first direction D1 to connect the principal surfaces 2a, 2b. The pair of side surfaces 2e also extend in the second direction D2 to connect the pair of end surfaces 2c. The laminated coil component 1 is mounted to an electronic device (e.g., a circuit board or an electronic component) by, for example, soldering. In the laminated coil component 1, the principal surface 2a constitutes a mounting surface that faces the electronic device.

[0024] As shown in FIG. 2, the element body 2 is configured by stacking multiple insulator layers 6 in a third direction D3. The element body 2 has multiple insulator layers 6 stacked in a first direction D1. In the element body 2, the stacking direction in which the multiple insulator layers 6 are stacked coincides with the third direction D3. In an actual element body 2, the multiple insulator layers 6 are integrated to the extent that the boundaries between each insulator layer 6 are not visible.

[0025] Each insulator layer 6 is formed of a dielectric material containing a glass component. That is, the element body 2 contains a dielectric material containing a glass component as a compound of elements that constitute the element body 2. The glass component is, for example, borosilicate glass. The dielectric material is, for example, a dielectric ceramic such as a BaTiO3-based, Ba(Ti,Zr)O3-based, or (Ba,Ca)TiO3-based material. Each insulator layer 6 is formed of a sintered ceramic green sheet containing a glass ceramic material.

[0026] A pair of external terminals 3 shown in FIGS. 1 to 4 are electrically connected to the ends of the coil 10, respectively. The pair of external terminals 3 are embedded in the element body 2 so as to be exposed from the main surface 2a. The pair of external terminals 3 are not exposed from the main surface 2b, the pair of end faces 2c, or the pair of side faces 2e. The pair of external terminals 3 are spaced apart from each other in the second direction D2. The pair of external terminals 3 are spaced apart from the pair of end faces 2c and the pair of side faces 2e, respectively, when viewed from a direction (first direction D1) perpendicular to the main surface 2a. One external terminal 3 is provided on one end face 2c side of the element body 2. The other external terminal 3 is provided on the other end face 2c side of the element body 2. The pair of external terminals 3 have the same shape.

[0027] The pair of external terminals 3 can also be said to be arranged in a pair of recesses provided in the main surface 2a. Each recess is a space recessed from the main surface 2a into the inside of the element body 2. Each recess has a shape corresponding to the shape of the corresponding external terminal 3. Each external terminal 3 is in contact with the entire inner surface of the corresponding recess without any gaps.

[0028] Each external terminal 3 has a substantially rectangular plate shape with the first direction D1 as its thickness direction. Each external terminal 3 has an exposed surface 3a exposed from the main surface 2a and an inner surface 3s disposed within the element body 2. The exposed surface 3a faces the outside of the element body 2 and is exposed from the main surface 2a. The exposed surface 3a is located in substantially the same plane as the main surface 2a, but may be located outside the element body 2 relative to the main surface 2a, or may be located inside the element body 2 relative to the main surface 2a.

[0029] The inner surface 3s is disposed opposite the element body 2 and is not exposed from the main surface 2a. The inner surface 3s is in contact with the element body 2 without any gaps. The inner surface 3s has an opposing surface 3b and a connecting surface 3t. The opposing surface 3b is opposed to the exposed surface 3a in the thickness direction (first direction D1). The opposing surface 3b faces the inside of the element body 2 and is opposed to the main surface 2b. When viewed from the first direction D1, the exposed surface 3a and the opposing surface 3b have, for example, a rectangular shape. The long side directions of the exposed surface 3a and the opposing surface 3b coincide with the third direction D3. The short side directions of the exposed surface 3a and the opposing surface 3b coincide with the second direction D2.

[0030] The connecting surface 3t connects the exposed surface 3a and the opposing surface 3b. The connecting surface 3t includes a pair of first connecting surfaces 3c and a pair of second connecting surfaces 3e. The pair of first connecting surfaces 3c and the pair of second connecting surfaces 3e connect the exposed surface 3a and the opposing surface 3b, respectively. The first connecting surfaces 3c and the second connecting surfaces 3e are arranged adjacent to each other.

[0031] The pair of first connecting surfaces 3c face each other in the second direction D2. The pair of first connecting surfaces 3c face in opposite directions in the second direction D2. One first connecting surface 3c faces the outside of the element body 2, and the other first connecting surface 3c faces the inside of the element body 2. The pair of external terminals 3 are arranged so that the other first connecting surfaces 3c face each other. One first connecting surface 3c faces the corresponding end surface 2c. The corresponding end surface 2c is the closer end surface 2c of the pair of end surfaces 2c. The pair of second connecting surfaces 3e face each other in the third direction D3. The pair of second connecting surfaces 3e face in opposite directions in the third direction D3. Each second connecting surface 3e faces the corresponding side surface 2e. The corresponding side surface 2e is the closer side surface 2e of the pair of side surfaces 2e.

[0032] The external terminal 3 is configured by stacking a plurality of electrode layers 11, 12 in the third direction D3. The external terminal 3 has a plurality of electrode layers 11, 12 stacked in the third direction D3. The plurality of electrode layers 11, 12 are arranged alternately. The electrode layers 11, 12 have different shapes when viewed from the stacking direction (third direction D3). In this embodiment, the electrode layers 11, 12 have similar shapes when viewed from the stacking direction. The plurality of electrode layers 11, 12 are stacked such that the electrode layers 11, 12 having similar shapes when viewed from the stacking direction are adjacent to each other.

[0033] The electrode layers 11 and 12 are arranged so that the positions of the side surfaces constituting the exposed surface 3a in the first direction D1 coincide with each other. This forms a planar exposed surface 3a. When viewed from the stacking direction, the electrode layer 11 is larger than the electrode layer 12. The electrode layers 11 and 12 are arranged so that the centers in the second direction D2 coincide with each other. This means that the opposing surface 3b and the pair of first connecting surfaces 3c have a plurality of recesses 31 and a plurality of protrusions 32.

[0034] The plurality of recesses 31 and the plurality of protrusions 32 are arranged alternately in the third direction D3. The opposing surface 3b and the pair of first connecting surfaces 3c have an uneven shape. The plurality of recesses 31 have the same shape and the same depth. The plurality of protrusions 32 have the same shape and the same height. The uneven shapes of the pair of first connecting surfaces 3c are the same as each other. No recesses or protrusions are provided on each second connecting surface 3e.

[0035] The recesses 31 are grooves that are provided continuously across the entire opposing surface 3b and the pair of first connecting surfaces 3c. The recesses 31 provided on the opposing surface 3b and the recesses 31 provided on each of the first connecting surfaces 3c are connected to each other. The recesses 31 have a rectangular cross section. The protrusions 32 are ridges that are provided continuously across the entire opposing surface 3b and the pair of first connecting surfaces 3c. The protrusions 32 are ridges that have a rectangular cross section. The protrusions 32 provided on the opposing surface 3b and the protrusions 32 provided on each of the first connecting surfaces 3c are connected to each other. The protrusions 32 have a rectangular cross section.

[0036] The recesses 31 and the protrusions 32 are provided over the entire first connecting surface 3c in the first direction D1 and reach the exposed surface 3a. As a result, a pair of long sides of the exposed surface 3a have the same uneven shape. A pair of ends of the exposed surface 3a in the second direction D2 have the same uneven shape.

[0037] The connecting surface 3t has recesses 31 provided adjacent to the corners A of the main surface 2a when viewed from the first direction D1. The corners A of the main surface 2a are located between the adjacent end faces 2c and side faces 2e. In this embodiment, two adjacent recesses 31 are provided for only two corners A located on one side of the second connecting surface 3e, but adjacent recesses 31 may be provided for all four corners A.

[0038] The multiple electrode layers 11, 12 are integrated to the extent that the boundaries between the electrode layers 11, 12 are not visible. In this embodiment, the number of electrode layers 11, 12 is "3". Each electrode layer 11, 12 is provided in a defect portion formed in the corresponding insulator layer 6. The defect portion forms a recess. The electrode layers 11, 12 contain a conductive material. The conductive material contains, for example, Ag or Pd. The electrode layers 11, 12 are formed as a sintered body of a conductive paste containing conductive material powder. The conductive material powder contains, for example, Ag powder or Pd powder.

[0039] The electrode layers 11, 12 may further contain a glass component. That is, the electrode layers 11, 12 may be configured as a sintered body of a conductive paste containing a metal component made of conductive material powder and a glass component. The glass component is a compound of elements that constitute the element body 2 and is the same component as the glass component contained in the element body 2. The content of the glass component may be set appropriately. Each of the electrode layers 11, 12 extends along the second direction D2.

[0040] The coil 10 and the connecting conductors 26, 27 are disposed within the element body 2 and are not exposed from the element body 2. The coil 10 has a coil axis along the third direction D3. A pair of ends of the coil 10 are electrically connected to a pair of external terminals 3 (see FIG. 2). One end is electrically connected to one external terminal 3 by a connecting conductor 26. The other end is electrically connected to the other external terminal 3 by a connecting conductor 27.

[0041] The coil 10 has a first coil conductor 22, a second coil conductor 23, a third coil conductor 24, and a fourth coil conductor 25. The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, and the fourth coil conductor 25 are arranged along a first direction D1 in the following order: the first coil conductor 22, the second coil conductor 23, the third coil conductor 24, and the fourth coil conductor 25. The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, and the fourth coil conductor 25 each have a shape in which a portion of the loop is interrupted, and each has one end and the other end.

[0042] The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, and the fourth coil conductor 25 are formed to have a predetermined width (length in the direction intersecting the first direction D1) and height (length in the first direction). The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, and the fourth coil conductor 25 are formed to have the same width and height as one another.

[0043] The first coil conductor 22 is located in the same layer as the pair of electrode layers 11. The first coil conductor 22 is connected to the other electrode layer 11, which is located in the same layer, via a connection conductor 26. The connection conductor 26 is located in the same layer as the pair of electrode layers 11 and the first coil conductor 22. The connection conductor 26 connects the first coil conductor 22 to the other electrode layer 11. One end of the first coil conductor 22 is connected to the connection conductor 26. The one end of the first coil conductor 22 constitutes the other end of the coil 10. In this embodiment, the first coil conductor 22, the connection conductor 26, and the other electrode layer 11 are integrally formed.

[0044] The second coil conductor 23 is located in the same layer as the pair of electrode layers 12. The second coil conductor 23 is spaced apart from the pair of electrode layers 12 located in the same layer. The other end of the first coil conductor 22 and one end of the second coil conductor 23 are adjacent to each other in the first direction D1 and are in direct contact with each other. When viewed from the first direction D1, the other end of the first coil conductor 22 and one end of the second coil conductor 23 overlap each other.

[0045] The third coil conductor 24 is located in the same layer as the pair of electrode layers 11. The third coil conductor 24 is spaced apart from the pair of electrode layers 11 located in the same layer. The other end of the second coil conductor 23 and one end of the third coil conductor 24 are adjacent to each other in the first direction D1 and are in direct contact with each other. When viewed from the first direction D1, the other end of the second coil conductor 23 and one end of the third coil conductor 24 overlap each other.

[0046] The fourth coil conductor 25 is located in the same layer as the pair of electrode layers 12. The fourth coil conductor 25 is connected to one of the electrode layers 12, which is located in the same layer, via a connection conductor 27. The connection conductor 27 is located in the same layer as the pair of electrode layers 12 and the fourth coil conductor 25. The connection conductor 27 connects the fourth coil conductor 25 to one of the electrode layers 12. The other end of the fourth coil conductor 25 is connected to the connection conductor 27. The other end of the fourth coil conductor 25 constitutes one end of the coil 10. In this embodiment, the fourth coil conductor 25, the connection conductor 27, and one of the electrode layers 12 are integrally formed.

[0047] The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 contain a conductive material. The conductive material contains, for example, Ag or Pd. The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 are configured as a sintered body of a conductive paste containing conductive material powder. The conductive material powder contains, for example, Ag powder or Pd powder.

[0048] In this embodiment, the first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 contain the same conductive material as the external terminals 3. The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 may contain a conductive material different from that of the external terminals 3.

[0049] The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 are provided in the defects formed in the corresponding insulator layers 6. The first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26 and 27 are formed by firing a conductive paste located in the defects formed in the green sheet.

[0050] The defects formed in the green sheet are formed, for example, by the following process. First, a green sheet is formed by applying an element paste containing the constituent materials of the insulator layer 6 and a photosensitive material onto a substrate. The substrate is, for example, a PET film. The photosensitive material contained in the element paste may be either negative or positive, and any known material can be used. Next, a mask corresponding to the defects is used to expose and develop the green sheet by photolithography, thereby forming defects in the green sheet on the substrate. The green sheet with the defects formed therein is the element pattern.

[0051] The electrode layers 11, 12, the first coil conductor 22, the second coil conductor 23, the third coil conductor 24, the fourth coil conductor 25, and the connecting conductors 26, 27 are formed, for example, by the following process.

[0052] First, a conductive paste containing a photosensitive material is applied to a substrate to form a conductive material layer. The photosensitive material contained in the conductive paste may be either negative or positive, and any known photosensitive material can be used. Next, a mask corresponding to the defect is used, and the conductive material layer is exposed and developed by photolithography to form a conductive pattern on the substrate that corresponds to the shape of the defect.

[0053] The laminated coil component 1 can be obtained, for example, by the following process following the process described above. A conductive pattern is combined with a missing portion of an element pattern to prepare a sheet in which the element pattern and the conductive pattern are in the same layer. A predetermined number of prepared sheets are stacked to obtain a laminate, which is then heat-treated, and multiple green chips are obtained from the laminate. In this process, the green laminate is cut into chips, for example, using a cutting machine. This results in multiple green chips of a predetermined size. Next, the green chips are fired. This firing results in the laminated coil component 1. A plating layer may be formed on the surface of each external terminal 3. The plating layer is formed, for example, by electroplating or electroless plating. The plating layer contains, for example, Ni, Sn, or Au.

[0054] Since the laminated coil component 1 is formed using such a photolithography method, the external terminals 3 can be formed in any shape. In the above-described manufacturing method, sheets on which an element pattern and a conductor pattern are formed on the same layer are prepared, and then a predetermined number of the prepared sheets are stacked to form a laminate. However, the laminate may be formed by other methods. For example, the laminate may be formed by sequentially forming an element pattern and a conductor pattern on a single substrate for stacking by a photolithography method. That is, regardless of the manufacturing method, the element 2 only needs to have multiple insulator layers 6 having a laminated structure. Regardless of the manufacturing method, the external terminals 3 only need to have multiple electrode layers 11, 12 having a laminated structure.

[0055] As described above, in the laminated coil component 1, the external terminals 3 have inner surfaces 3s disposed within the element body 2, and the inner surfaces 3s have recesses 31 and protrusions 32. This increases the contact area between the element body 2 and the external terminals 3, improving the adhesion of the external terminals 3 to the element body 2. As a result, peeling of the external terminals 3 can be suppressed.

[0056] The recesses 31 and protrusions 32 are provided on both the opposing surface 3b and the connecting surface 3t of the inner surface 3s. This further increases the contact area between the element body 2 and the external terminals 3 compared to when only one of the opposing surface 3b and the connecting surface 3t has the recesses 31 and protrusions 32. This further reduces peeling of the external terminals 3.

[0057] The recessed portion 31 and the protruding portion 32 are provided on each of the pair of first connecting surfaces 3c of the connecting surface 3t. This further increases the contact area between the element body 2 and the external terminal 3 compared to when only one of the pair of first connecting surfaces 3c has the recessed portion 31 and the protruding portion 32. This further reduces peeling of the external terminal 3.

[0058] Stress tends to concentrate at the corner A. Therefore, if the external terminal 3 is disposed close to the corner A, the corner A may be damaged. In the laminated coil component 1, the connection surface 3t has a recess 31 adjacent to the corner A of the main surface 2a when viewed from the first direction D1. This increases the area of ​​the element body 2 at the corner A, making it possible to suppress damage to the corner A. In other words, the recess 31 can keep the external terminal 3 away from the corner A, thereby suppressing damage to the corner A (corner of the element body 2).

[0059] Each of the pair of external terminals 3 has a plurality of stacked electrode layers 11, 12. Therefore, by stacking the electrode layers 11, 12 together with the insulator layer 6, the external terminal 3 can be formed together with the element body 2. The electrode layers 11, 12 have different shapes when viewed from the stacking direction (third direction D3), and therefore, by alternately stacking the electrode layers 11, 12, an inner surface 3s having recesses 31 and protrusions 32 can be easily formed.

[0060] The pair of external terminals 3 are exposed only on the main surface 2a, which reduces the mounting area. For example, if the external terminals 3 are exposed on the main surface 2a and the end surface 2c, solder is also formed on the end surface 2c, which increases the mounting area.

[0061] Here, an example has been described in which the coil 10 has a coil axis along the third direction D3 and includes a first coil conductor 22, a second coil conductor 23, a third coil conductor 24, and a fourth coil conductor 25. However, the coil axis of the coil 10 does not have to be along the third direction D3. The coil axis of the coil 10 may be along, for example, the first direction D1 or the second direction D2. Furthermore, the number of coil conductors constituting the coil 10 is not limited to "4."

[0062] 5 is a bottom view of a laminated coil component 1A according to a first modified example of the first embodiment. As shown in FIG. 5, in the laminated coil component 1A, the plurality of electrode layers 11 are stacked at fixed positions in the second direction D2, whereas the plurality of electrode layers 12 are stacked while varying their positions in the second direction D2. The centers of the electrode layers 11 and 12 in the second direction D2 do not necessarily coincide. This results in a complex uneven shape on the inner surface 3s and on each long side of the exposed surface 3a in the laminated coil component 1A.

[0063] In the laminated coil component 1A as well, the inner surface 3s has the recessed portions 31 and the protruding portions 32, which can prevent peeling of the external terminals 3. In the laminated coil component 1A, the pair of exposed surfaces 3a have the same shape, but the shapes of the pair of exposed surfaces 3a can also be made different by making the positions of the corresponding electrode layers 11 different from each other. In this case, the pair of external terminals 3 can be easily identified by appearance alone. In the laminated coil component 1A, instead of the plurality of electrode layers 12, a plurality of electrode layers 11 may be stacked while varying their positions in the second direction D2.

[0064] 6 is a bottom view of a laminated coil component 1B according to a second modified example of the first embodiment. As shown in FIG. 6, in the laminated coil component 1B, when viewed from the first direction D1, each connecting surface 3t has two recesses 31 adjacent to a corner A of the main surface 2a. Each of the four corners A of the main surface 2a is adjacent to a corresponding recess 31. The recesses 31 are provided across the entire connecting surface 3t in the first direction D1. The recesses 31 are provided across one first connecting surface 3c and each second connecting surface 3e. The recesses 31 are provided at corners formed by one first connecting surface 3c and each second connecting surface 3e in the external terminal 3.

[0065] When viewed from the first direction D1, the inner surface of the recess 31 is composed of a plane parallel to the end face 2c and a plane parallel to the side face 2e. The external terminal 3 has a plurality of stacked electrode layers, but the shape and stacking direction of each electrode layer are not limited. The opposing surface 3b may or may not have a recess 31 or a protrusion 32.

[0066] Fig. 7 is a bottom view of a laminated coil component 1C according to a third modified example of the first embodiment. As shown in Fig. 7, in the laminated coil component 1C, as with the laminated coil component 1B shown in Fig. 6, when viewed from the first direction D1, each connection surface 3t has two recesses 31 adjacent to the corners A of the main surfaces 2a. The laminated coil component 1C differs from the laminated coil component 1B in that the inner surfaces of the recesses 31 are formed by curved surfaces.

[0067] When viewed from the first direction D1, the recess 31 has a portion recessed inward of the external terminal 3 relative to a straight line connecting the end of the first connecting surface 3c and the end of the second connecting surface 3e. When viewed from the first direction D1, a chamfered shape consisting of a straight line is not included in the recess 31. The external terminal 3 has multiple stacked electrode layers, but the shape and stacking direction of each electrode layer are not limited. The opposing surface 3b may or may not have a recess 31 or a protrusion 32.

[0068] In the laminated coil components 1B and 1C as well, at least the connection surface 3t has the recess 31, which can prevent peeling of the external terminal 3. In addition, the recess 31 is provided adjacent to the corner A, which prevents damage to the corner A.

[0069] FIG. 8 is a bottom view of a laminated coil component 1D according to a fourth modified example of the first embodiment. The laminated coil component 1D shown in FIG. 8 differs from the laminated coil component 1 in that the element body 2 has a plurality of insulator layers stacked in the second direction D2, and the external terminal 3 has a plurality of electrode layers 13, 14 stacked in the second direction D2. The electrode layers 13, 14 have, for example, different shapes (here, similar shapes) when viewed from the stacking direction (second direction D2). The number of electrode layers 13 is "3," and the number of electrode layers 14 is "2." When viewed from the stacking direction, the electrode layers 13 are larger than the electrode layers 14. The shapes of the coil 10 and the connecting conductors 26, 27 are appropriately set so that the coil 10 is connected to a pair of external terminals 3.

[0070] In the laminated coil component 1D, the opposing surface 3b (see FIG. 1) and the pair of second connecting surfaces 3e have a plurality of recesses 31 and a plurality of protrusions 32. The recesses 31 and the protrusions 32 are alternately arranged in the second direction D2. The pair of short sides of the exposed surface 3a have the same uneven shape. In the laminated coil component 1D, the opposing surface 3b and the pair of second connecting surfaces 3e each have the recesses 31 and the protrusions 32, so that peeling of the external terminals 3 can be suppressed. Compared to when only one of the pair of second connecting surfaces 3e has the recesses 31 and the protrusions 32, the contact area between the element body 2 and the external terminals 3 is further increased. Therefore, peeling of the external terminals 3 can be further suppressed.

[0071] In the laminated coil component 1D, the centers of the electrode layers 13 and 14 in the third direction D3 are aligned when viewed from the second direction D2, but they do not have to be aligned. In the external terminal 3, the electrode layer 13 is disposed at the end on the corresponding end face 2c side, but the electrode layer 14 may also be disposed therein. In this case, the recess 31 can be disposed in the connection surface 3t so as to be adjacent to the corner A of the main surface 2a.

[0072] In the laminated coil components 1, 1A, and 1D, the external terminals 3 may be composed of only a plurality of electrode layers having the same shape when viewed from the stacking direction. Even in this case, if the plurality of electrode layers are stacked while being shifted in directions perpendicular to both the stacking direction and the first direction D1, the recesses 31 and the protrusions 32 can be formed on the connecting surfaces 3t. That is, in the laminated coil components 1 and 1A, if the plurality of electrode layers are stacked while changing their positions in the second direction D2, the recesses 31 and the protrusions 32 can be formed on the first connecting surfaces 3c. In the laminated coil component 1D, if the plurality of electrode layers are stacked while changing their positions in the third direction D3, the recesses 31 and the protrusions 32 can be formed on the second connecting surfaces 3e.

[0073] In the laminated coil components 1 and 1A, the external terminals 3 have electrode layers 11 and 12 with different shapes, but may have three or more types of electrode layers with different shapes.In the laminated coil component 1D, the external terminals 3 have electrode layers 13 and 14 with different shapes, but may have three or more types of electrode layers with different shapes.

[0074] [Second embodiment] 9, 10(a), and 10(b), a laminated coil component 1E according to the second embodiment differs from the laminated coil component 1 in that the opposing surfaces 3b of the external terminals 3 have recesses 33 and protrusions 34, and the connecting surfaces 3t have no recesses or protrusions, but in other respects is the same as the laminated coil component 1. In the laminated coil component 1E, the opposing surfaces 3b have an uneven shape, and the connecting surfaces 3t do not have an uneven shape.

[0075] In the laminated coil component 1E, the opposing surface 3b has a ring-shaped or frame-shaped protrusion 34 when viewed from the first direction D1. The protrusion 34 is a ridge having a rectangular ring-shaped or rectangular frame-shaped configuration and protruding in the first direction D1. In the present embodiment, the protrusion 34 is continuous without interruption along the entire circumference of the connecting surface 3t, but may be discontinuous as long as it has a ring-shaped or frame-shaped configuration as a whole. The recess 33 is provided inside the protrusion 34. When viewed from the first direction D1, the recess 33 has a rectangular shape. The recess 33 has a rectangular cross section.

[0076] The external terminal 3 has a plurality of stacked electrode layers, but the shape and stacking direction of each electrode layer are not limited. The external terminal 3 is formed, for example, by stacking a plurality of electrode layers in the third direction D3. In this case, electrode layers whose shape as viewed in the thickness direction matches the cross-sectional shape shown in Figure 10(b) are stacked at all ends in the stacking direction, and electrode layers without recesses or protrusions are stacked at all ends in the stacking direction.

[0077] In the laminated coil component 1E, the opposing surface 3b also has recesses 33 and protrusions 34. Therefore, the recesses 33 and protrusions 34 are easily caught by stress in the second direction D2 or the third direction D3. This effectively prevents the external terminals 3 from peeling. Furthermore, the increased contact area between the external terminals 3 and the element body 2 also prevents peeling due to stress in the first direction D1. The protrusions 34 have an annular shape when viewed from the first direction D1. They are symmetrically arranged with respect to a line parallel to the second direction D2 and passing through the center of the opposing surface 3b, and are also symmetrically arranged with respect to a line parallel to the third direction D3 and passing through the center of the opposing surface 3b. Because the protrusions 34 have an annular shape, they are less likely to be formed unevenly with respect to the opposing surface 3b in the second direction D2 and the third direction D3. This reduces distortion due to shrinkage during sintering. Since the connecting surface 3t does not have recesses or protrusions, the external terminals 3 can be reduced in size in the second direction D2 and the third direction D3.

[0078] As shown in FIGS. 11(a) and 11(b), the opposing surface 3b of the external terminal 3 may further have a protrusion 35. The protrusion 35 is spaced apart from the protrusion 34 and is provided in the center of the bottom surface of the recess 33. Therefore, the recess 33 is a rectangular annular groove when viewed from the first direction D1. In this embodiment, the recess 33 is continuous without interruption along the entire circumference of the connecting surface 3t when viewed from the first direction D1, but it may be discontinuous as long as it is annular as a whole. Like the protrusion 34, the recess 33 also has an annular shape, so distortion due to shrinkage during sintering is unlikely to occur.

[0079] In the laminated coil component 1E, the protrusions 34 have an annular shape when viewed from the first direction D1, but the shape is not limited thereto. For example, a plurality of dot-shaped protrusions 34 may be provided on the opposing surface 3b. Furthermore, when viewed from the first direction D1, the protrusions 34 may have a cross shape as shown in Fig. 12(a), an H shape as shown in Fig. 12(b), or a rectangular shape with protrusions on each side as shown in Fig. 12(c).

[0080] 13, the facing surface 3b of the external terminal 3 may have a protrusion 36 with a wide tip (length in the second direction D2) and a T-shaped cross section. For example, a plurality of protrusions 36 may be provided on the facing surface 3b in a dot pattern. The wide tip of the protrusion 36 functions as an anchor and catches on the element body 2. The shape of the protrusion 36 particularly suppresses movement of the external terminal 3 in the first direction D1. This further suppresses peeling of the external terminal 3 from the element body 2.

[0081] [Third embodiment] 14 and 15, a laminated coil component 1F according to the third embodiment differs from the laminated coil component 1 in that the connection surfaces 3t of the external terminals 3 have recesses 37 and protrusions 38, while the opposing surfaces 3b have no recesses or protrusions, but in other respects is the same as the laminated coil component 1. In the laminated coil component 1F, the connection surfaces 3t have an uneven shape, while the opposing surfaces 3b do not have an uneven shape.

[0082] In the laminated coil component 1F, a recess 37 and a pair of protrusions 38 are provided on the connecting surface 3t. The recess 37 and the pair of protrusions 38 extend in a direction intersecting the first direction D1. The recess 37 and the pair of protrusions 38 extend in the third direction D3 on the first connecting surface 3c and in the second direction D2 on the second connecting surface 3e. The recess 37 and the pair of protrusions 38 are provided substantially parallel to the exposed surface 3a. The recess 37 is a notched groove provided in the approximate center of the connecting surface 3t in the first direction D1. The pair of protrusions 38 are ridges provided on both sides of the recess 37 in the first direction D1. The recess 37 and the pair of protrusions 38 are provided continuously around the entire circumference of the connecting surface 3t. The recess 37 and the pair of protrusions 38 may be provided only in a partial section rather than around the entire circumference of the connecting surface 3t. For example, the recess 37 may be provided only on the first connecting surface 3c.

[0083] In the laminated coil component 1F, the recesses 37 and the protrusions 38 are also provided on the connection surfaces 3t, thereby preventing peeling of the external terminals 3. The recesses 37 and the protrusions 38 are provided on each of the pair of first connection surfaces 3c and the pair of second connection surfaces 3e, respectively, thereby preventing peeling of the external terminals 3 reliably. The recesses 37 and the protrusions 38 extend along the exposed surface 3a in a direction intersecting the first direction D1. Therefore, the recesses 37 and the protrusions 38 function as anchors and are hooked onto the element body 2. In particular, movement of the external terminals 3 in the first direction D1 is prevented. This further prevents peeling of the external terminals 3.

[0084] The above describes the embodiments and modifications of the present invention, but the present invention is not necessarily limited to the above-described embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention.

[0085] The respective embodiments and the respective modified examples may be combined as appropriate. For example, the second connecting surface 3e of the laminated coil component 1 may be provided with a recess 37 and a pair of protrusions 38 similar to those of the laminated coil component 1F. The connecting surface 3t of the laminated coil component 1E may be provided with a recess 37 and a pair of protrusions 38 similar to those of the laminated coil component 1F. Of the pair of external terminals 3, one external terminal 3 may be provided with a recess or a protrusion on the opposing surface 3b, and the other external terminal 3 may be provided with a recess or a protrusion on the connecting surface 3t. It is sufficient that the recess or the protrusion is provided on the inner surface 3s of at least one of the pair of external terminals 3. [Explanation of symbols]

[0086] 1, 1A, 1B, 1C, 1D, 1E, 1F... multilayer coil component, 2... element body, 2a, 2b... main surface, 2c... end surface, 2e... side surface, 3... external terminal, 3a... exposed surface, 3b... opposing surface, 3c... first connecting surface, 3e... second connecting surface, 3s... inner surface, 3t... connecting surface, 6... insulator layer, 10... coil, 11, 12, 13, 14... electrode layer, 31, 33, 37... recess, 32, 34, 35, 36, 38... protruding portion, A... corner portion.

Claims

1. an element body having a plurality of stacked insulator layers; a coil disposed within the element body; a pair of external terminals electrically connected to the coil; the element body has a rectangular parallelepiped shape and includes a pair of main surfaces facing each other in a first direction, a pair of end surfaces facing each other in a second direction intersecting the first direction, and a pair of side surfaces facing each other in a third direction intersecting the first direction and the second direction, The pair of external terminals are the first and second electrodes are embedded in the element body and spaced apart from each other in the second direction and spaced apart from the pair of end faces and the pair of side faces, each having an exposed surface exposed from one of the main surfaces and an inner surface disposed within the element body, the inner surface has an opposing surface facing the exposed surface and a connecting surface connecting the exposed surface and the opposing surface, The connection surface has a recess or a protrusion, The opposing surface does not have any recesses or protrusions. Multilayer coil components.

2. the connecting surface includes a pair of first connecting surfaces facing each other in the second direction, The pair of first connecting surfaces each have a concave portion or a convex portion. The laminated coil component according to claim 1 .

3. the connecting surface includes a pair of second connecting surfaces facing each other in the third direction, The pair of second connecting surfaces each have a concave portion or a convex portion. The laminated coil component according to claim 1 or 2.

4. When viewed from the first direction, the connection surface has a recess adjacent to a corner of the main surface. The laminated coil component according to any one of claims 1 to 3.

5. The connection surface has a recess or a protrusion extending along a direction intersecting the first direction. The laminated coil component according to any one of claims 1 to 4.

6. Each of the pair of external terminals has a plurality of stacked electrode layers. The laminated coil component according to any one of claims 1 to 5.

7. The plurality of electrode layers are stacked such that electrode layers having different shapes are adjacent to each other when viewed from a stacking direction of the plurality of electrode layers. The laminated coil component according to claim 6 .

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